Hartley Taylor

9th Oxford Bone Infection Conference (OBIC)

8 December 2020
Virtual Event

Selected Abstracts and Posters

 

Abstracts

Free Papers 1
The twin terror: fungal and tuberculous co-infection of the spine in a non-immunocompromised patient

Selected Abstract

The twin terror: fungal and tuberculous co-infection of the spine in a non-immunocompromised patient

Ahmad Arieff Atan1, Irda Yuhanis Ahmad Zaidi2, Mohammad Azmy Hamron3, Mustaqim Afifi3, Naveen Vijayasingham3 

1Department of Orthopaedic and Traumatology, Hospital Tuanku Jaafar Seremban, Negeri Sembilan, Malaysia. 2Department of Pathology, Hospital Tuanku Jaafar Seremban, Negeri Sembilan, Malaysia. 3Department of Orthopaedic, Hospital Tawau, Sabah, Malaysia

Simultaneous infection of both fungal and tuberculous organisms is a very remote occurrence, especially in a non-immunocompromised patient. A previously-healthy 66 years old male presented with severe backpain and weakness of lower limbs for 2 weeks. Examination revealed localised tenderness at thoracolumbar region, with both lower limbs exhibited grade 3 muscle power. Laboratory investigations showed normal white cell count and erythrocyte sedimentation rate. Thoracolumbar radiograph revealed collapse of T11 with endplates erosion. Magnetic resonance imaging confirmed the findings, and found abscess within T10/T11 intervertebral disc space, extending to the paraspinal region. He underwent debridement, posterior decompression and stabilisation of thoracolumbar spine. Intraoperative culture yielded growth of Candida albicans. Surprisingly, Mycobacterium tuberculosis was also isolated from bone and tissue culture. Polymerase-chain reaction (PCR) test for tuberculosis returned positive. Combination of antituberculosis (anti-TB) regime and oral antifungal medication was started. He gradually recovered, currently ambulating with walking frame. Despite its rarity, fungal and tuberculous co-infection of the spine should be managed the way it is treated when occurred individually – by prioritising medical therapy and combining with surgery whenever it is indicated.  Early diagnosis and commencement of treatment have shown to correlate with good outcomes.

Abstract without diagnosis

A previously-healthy 66 years old male presented with severe backpain and weakness of lower limbs for 2 weeks. Examination revealed localised tenderness at thoracolumbar region, with both lower limbs exhibited grade 3 muscle power. Laboratory investigations showed normal white cell count and erythrocyte sedimentation rate. Thoracolumbar radiograph revealed collapse of T11 with endplates erosion. Magnetic resonance imaging confirmed the findings, and found abscess within T10/T11 intervertebral disc space, extending to the paraspinal region. He underwent debridement, posterior decompression and stabilisation of thoracolumbar spine. Intraoperative culture yielded growth of two different non-pyogenic organisms.  Polymerase-chain reaction (PCR) test for one of the organism returned positive. Oral medications targeting both organism was started in combination. He gradually recovered, currently ambulating with walking frame. Despite its rarity, non-pyogenic co-infection of the spine should be managed the way it is treated when occurred individually – by prioritising medical therapy and combining with surgery whenever it is indicated.  Early diagnosis and commencement of treatment have shown to correlate with good outcomes.

Free Papers 1
A rare form of osteomyelitis(?) located the proximal lower leg

Selected Abstract

A rare form of osteomyelitis(?) located the proximal lower leg

Jan Hendrik Rolfing1,2, Klaus Kjær Petersen3

1Department of Orthopedic Surgery, Aarhus University Hospital, Aarhus, Denmark. 2. 3Department of orthopedic Surgery, Aarhus University Hospital, Aarhus, Denmark

A thirty year old healthy woman with no known diseases or injuries. She has just moved to our area. For about seven years she has been bothered by swelling and light pain in the left lower leg. Radiographs was taken showing slcerotic changes in the proximal tibia and fibula and destruction of the proximal tibiofibular joint.

At “elsewhere hospital” biopsies were taken previously. All cultures and PCR were negative. Histiology showed “chronic inflammation, no malignity”.  Fungal osteomyelits were suspected on the basis of the radiological examinations. Blood titre of Aspergillus was very high and decreased after starting antifungal treatment – and increased again after discontinuation. So we believe it is a fungal osteomyelitis.

The patient is doing fine: can look after a full time standing and walking job and has just given birth to her second child.

What to do?!

Abstract without diagnosis

A thirty year old healthy woman with no known diseases or injuries. She has just moved to our area. For about seven years she has been bothered by swelling and light pain in the left lower leg. Radiographs was taken showing slcerotic changes in the proximal tibia and fibula and destruction of the proximal tibiofibular joint.

At “elsewhere hospital” biopsies were taken previously. All cultures and PCR were negative. Histiology showed “chronic inflammation, no malignity”.

What is the diagnosis and what to do?!

Free Papers 1
Cysticercosis of the foot –Case report of a rare pseudo-tumour

Selected Abstract

Cysticercosis of the foot –Case report of a rare pseudo-tumour

Sachindra Nayak Kapadi1, Prathap Parvataneni2, Sanjeev Musuvathy Ravi1

1Wrightington Wigan and Leigh NHS, Wigan. 2KIMS hospital, Hyderabad, India

Introduction: Cysticercosis in humans is due to Taenia Solium parasite infection. They most commonly affect the central nervous system and less commonly the eye and striated muscles.  We would like to present one such case which we came across in clinical practice and posed a serious diagnostic dilemma.

Case report: A 22 year old Indian female presented to our teaching hospital in southern India with complains of an atraumatic swelling and pain in her left foot for a week. She had no constitutional symptoms. On local examination there was diffuse swelling and redness on both dorsal and plantar surface of the foot with no local rise of temperature. Palpation revealed a 2 x 2 cm deep swelling with undefined margins.

Investigations: Besides an ESR of 75 mm/hr, all her other blood investigations were normal. At this juncture the differential diagnosis was that of a soft tissue tumour and it was decided to go ahead with a MRI scan. MRI foot showed small cystic scolex shaped lesion measuring 8 millimeter in the plantar aspect deep to flexor tendons at the level of 2nd metatarsal with a hypo tense focus and associated collection which confirmed a striated muscle Cysticerocosis.

Treatment – The patient was treated conservatively with a combination of albendazole, analgesics and a single intramuscular steroid injection. She made a dramatic recovery in one and half months’ time.

Conclusion: Cysticerocosis can affect the muscles of the foot and mimic a tumour. It can however be treated conservatively with good clinical outcome.

Abstract without diagnosis

Case report: A 22 year old Indian female presented to our teaching hospital in southern India with complains of an atraumatic swelling and pain in her left foot for a week. She had no constitutional symptoms. On local examination there was diffuse swelling and redness on both dorsal and plantar surface of the foot with no local rise of temperature. Palpation revealed a 2 x 2 cm deep swelling with undefined margins. The swelling was subcutaneous and was clinically not affecting the small joint of the foot.

Investigations: Besides an ESR of 75 mm/hr all her other blood investigations were normal.  X ray of the foot was normal as well. At this juncture the differential diagnosis was that of a soft tissue tumour and it was decided to go ahead with a MRI scan. MRI foot showed small cystic scolex shaped lesion measuring 8 millimeter in the plantar aspect deep to flexor tendons at the level of 2nd metatarsal with a hypo tense focus and associated collection

Treatment: The patient was treated conservatively with a combination of albendazole, analgesics and a single intramuscular steroid injection. She made a dramatic recovery in one and half months’ time.

Free Papers 1
Locally invasive Aspergillus infection of the iliac bone: a unique case

Selected Abstract

Locally invasive Aspergillus infection of the iliac bone: a unique case

Abi Manesh, Boopalan PRJVC, Abel Livingston

Christian Medical College, Vellore, India

 

Introduction: A 46 years old radiology technician from South India presented with complaints of right hip pain since four months. He described the pain as a constant ache, with no radiation, and exacerbated particularly by movements. The hip pain had also been limiting with work and activities of daily living and he was limping for the last 2 months. On examination he had a pain free full range of movement in his right hip.  He did not have sacroiliac joint tenderness as well. He has history of receiving multiple injections in the right gluteal area. He has diabetes mellitus for seven years and is on insulin therapy.  

 Investigations: His bloods showed mildly elevated inflammatory markers with a negative rheumatological screen. X-Ray revealed osteolyelitic changes in the right iliac bone. The MRI revealed an altered marrow signal intensity involving the right iliac wing in the form of T1 intermediate and T2 and STIR heterogeneous hyperintensity suggestive of osteomyelitis with collections around the iliac crest and surrounding muscles. He underwent debridement and biopsy of the right iliac bone under general anesthesia. The biopsy showed chronic granulomatous inflammation with septate fungal hyphae. The fungal cultures grew aspergillus flavus sensitive to amphotericin and voriconazole.

Treatment: He was commenced on voriconazole. He had full symptom resolution on therapy and his MRI 6 months later showed near complete resolution of the previous changes.

Conclusion: Aspergillus, a ubiquitous fungus may rarely present with locally invasive bone infections especially in patients with uncontrolled diabetes mellitus.

Abstract without diagnosis

Introduction: A 46 years old radiology technician from South India presented with complaints of right hip pain since four months. He described the pain as a constant ache, with no radiation, and exacerbated particularly by movements. The hip pain had also been limiting with work and activities of daily living and he was limping for the last 2 months. On examination he had a pain free full range of movement in his right hip.  He did not have sacroiliac joint tenderness as well. He has history of receiving multiple injections in the right gluteal area. He has diabetes mellitus for seven years and is on insulin therapy. 

 Investigations: His bloods showed mildly elevated inflammatory markers with a negative rheumatological screen. X-Ray revealed osteolyelitic changes in the right iliac bone. The MRI revealed an altered marrow signal intensity involving the right iliac wing in the form of T1 intermediate and T2 and STIR heterogeneous hyperintensity suggestive of osteomyelitis with collections around the iliac crest and surrounding muscles. He underwent debridement and biopsy of the right iliac bone under general anesthesia. The biopsy showed chronic granulomatous inflammation with septate fungal hyphae. What is the likely diagnosis?

Free Papers 1
Retained topical negative pressure dressing foam masquerading as sacral osteomyelitis

Selected Abstract

Retained topical negative pressure dressing foam masquerading as sacral osteomyelitis

Johann Jeevaratnam, Alex Ramsden

Oxford University Hospitals NHS Foundation Trust, Oxford

We present the case of a 63-year-old diabetic gentleman, who was referred to the Oxford Bone Infection Unit due to concern regarding a non-healing sacral wound and suspected underlying osteomyelitis.  The wound resulted following a prolonged period of immobility while on critical care following coronary heart bypass surgery in November 2017.

Magnetic resonance imaging at the referring hospital raised concern with regard to sacral osteomyelitis, which they managed locally with intravenous antibiotics and topical negative pressure (TNP) dressings.

Despite removal of retained TNP sponge by the Practice Nurse in March 2019, the wound failed to heal. Further MRI suggested possible osteomyelitis in the coccyx and sacrum.  The patient underwent wound excision, bone sampling and local muscle flap closure in Oxford, in October 2019, approximately two years after the inciting incident.

Peri-operative findings were that of extensive chronic inflammatory tissue around what appeared to be retained TNP sponge, lying 10 cm cranial to the sinus opening.  Both sacrum & coccyx were healthy. Histopathology ultimately confirmed these suspicions, identifying a mesh-like foreign body.

The patient went on to achieve primary healing with no further wound concerns.

Abstract without diagnosis

We present the case of a 63-year-old diabetic gentleman, who was referred to the Oxford Bone Infection Unit due to concern regarding a non-healing sacral wound and suspected underlying osteomyelitis.  The wound resulted following a prolonged period of immobility while on critical care following coronary heart bypass surgery in November 2017.

Magnetic resonance imaging at the referring hospital raised concern with regard to sacral osteomyelitis, which they managed locally with intravenous antibiotics and topical negative pressure (TNP) dressings.

Despite removal of retained TNP sponge by the Practice Nurse in March 2019, the wound failed to heal. Further MRI suggested possible osteomyelitis in the coccyx and sacrum.  The patient underwent wound excision, bone sampling and local muscle flap closure in Oxford, in October 2019, approximately two years after the inciting incident.

The patient went on to achieve primary healing with no further wound concerns.

Free Papers 1
Two organisms working together: A case of dual pathology

Selected Abstract

Two organisms working together: A case of dual pathology

Janine Carter

Leeds Teaching Hospitals, Leeds

A 40 year old fit stay-at-home dad first presented with right upper lobe pneumonia at the end of 2017. Despite standard pneumonia investigations and treatment he subsequently developed a subcutaneous collection to the posterior back, which was drained. He was given multiple courses of antibiotics for skin and soft tissue infection but continued to complain of discharge and pain. The respiratory team requested interval imaging to assess the right upper lobe changes, which incidentally picked up T2-T7 osteomyelitis and a paravertebral abscess. CT-guided biopsy grew Aggregatibacter actinomycetemcomitans. Gram staining of the tissue revealed Gram positive filamentous organisms suspicious for Actinomyces. These two pathogens are well known to co-exist. On questioning, the patient recalled dental issues culminating in a tooth extraction which was thought to be the source. We postulated a haematogenous route of dissemination; happily TTE was normal with no features of endocarditis.

The patient was managed with IV ceftriaxone via OPAT, followed by a long course of PO doxycycline 200mg OD to treat Actinomycosis.

 

Abstract without diagnosis

A 40 year old fit stay-at-home dad first presented with right upper lobe pneumonia at the end of 2017. Despite standard pneumonia investigations and treatment he subsequently developed a subcutaneous collection to the posterior back, which was drained. He was given multiple courses of antibiotics for skin and soft tissue infection but continued to complain of discharge and pain. The respiratory team requested interval imaging to assess the right upper lobe changes, which incidentally picked up T2-T7 osteomyelitis and a paravertebral abscess. CT-guided biopsy grew a Gram negative coccobacillus. Gram staining of the tissue revealed Gram positive filamentous organisms. These two pathogens are well known to co-exist. On questioning, the patient recalled dental issues culminating in a tooth extraction which was thought to be the source. We postulated a haematogenous route of dissemination; happily TTE was normal with no features of endocarditis.

The patient was managed with IV ceftriaxone via OPAT, followed by a long course of PO doxycycline 200mg OD.

Free Papers 1
Double-barrel non-vascularised free fibular graft for treatment of non-union following distraction osteogenesis after resection of chronic osteomyelitis of the femur

Selected Abstract

Double-barrel non-vascularised free fibular graft for treatment of non-union following distraction osteogenesis after resection of chronic osteomyelitis of the femur

 Ahmad Arieff Atan1, Sughilan Sundara Murthi2, Khong Wee Lee2, Idris Abu Bakar2, Mustaqim Afifi2

1Department of Orthopaedic, Hospital Tuanku Ja’afar, Seremban, Negeri Sembilan, Malaysia. 2Department of Orthopaedic, Hospital Tawau, Tawau, Sabah, Malaysia

A huge gap following resection of infected bone usually necessitates a longer duration of bony transport for distraction osteogenesis. Non-union at docking site is a common complication, and normally requires bone grafting with favourable osteogenetic capability, such as a vascularised bone graft. A 20 years old male was diagnosed with chronic osteomyelitis of left femur, after presented with swelling and pus discharge from the left thigh. Initial radiograph revealed irregular, thickened cortical surfaces with multiple lytic area. Further evaluation using MRI and CT scan revealed presence of multiple sequestrum and involucrum, with a communicating intramuscular sinus extending to the anteromedial subcutaneous area. He underwent resection of the infected bone, application of limb reconstruction system (LRS) monorail and cement spacer insertion. The resected part measured about 29.5cm. After 2 weeks, the cement spacer was removed and corticotomy for bone transport was done. The culture grew Staphylococcus aureus, and he completed antibiotics regime for 6 weeks. Subsequently, the infection was eradicated and bony transport was successful to regenerate new bone at the resected part. Total bone transport duration was about 10 months. However, as anticipated, it was complicated with fibrous non-union at the docking site. He underwent bone grafting using double-barrel non-vascularised free fibular graft, while the LRS was removed and replaced with a long reverse distal femoral locking plate. After 10 weeks, the bone achieved union and he was able to walk without support. Double-barrel non-vascularised fibular graft is a viable option for management of non-union after long-duration bone transport.

Abstract without Diagnosis

A 20 years old male presented with swelling and pus discharge from the left thigh. Initial radiograph revealed irregular, thickened cortical surfaces with multiple lytic area. Further evaluation using MRI and CT scan revealed presence of multiple sequestrum and involucrum, with a communicating intramuscular sinus extending to the anteromedial subcutaneous area. He underwent bone resection, application of limb reconstruction system (LRS) monorail and cement spacer insertion. The resected part measured about 29.5cm. After 2 weeks, the cement spacer was removed and corticotomy for bone transport was done. He completed antibiotics regime for 6 weeks. Subsequently, the infection was eradicated and bony transport was successful to regenerate new bone at the resected part. Total bone transport duration was about 10 months. Due to the anticipated complication, he underwent bone grafting using double-barrel non-vascularised free fibular graft, while the LRS was removed and replaced with a long reverse distal femoral locking plate. After 10 weeks, the bone achieved union and he was able to walk without support

Free papers 2a
Does local implantation of gentamicin impair renal function in patients undergoing surgery for chronic osteomyelitis and fracture-related infection?

Selected Abstract

Does local implantation of gentamicin impair renal function in patients undergoing surgery for chronic osteomyelitis and fracture-related infection?

Catherine Birnie, Robert Hyder-Wilson, Jamie Ferguson, Martin McNally

Bone Infection Unit, Oxford

Abstract

Introduction: Chronic osteomyelitis is often treated with local antibiotic carrier implantation following dead bone excision. Whilst gentamicin has been used locally, concerns have existed of induced renal dysfunction due to systemic toxicity.

Method: 163 patients had single-stage chronic osteomyelitis excision and void filling with Cerament G™, containing gentamicin. 

Mean carrier volume was 10.9mls (range 1-30mls) and mean gentamicin dosing was 190.75mg (maximum 525mg). Seven patients had pre-existing renal disease.

Serum creatinine levels were collected pre-operatively and during the first seven days post-operatively. Glomerular filtration rate (GFR) was calculated using the CKD-epi creatinine equation. Renal function was described using the Chronic Kidney Disease (CKD) Staging. 

Results: 155 cases had a pre- and post-operative GFR. Pre-operative CKD staging demonstrated 118 Class I, 30 Class II, 3 Class IIIa, 3 Class IIIb, and 1 Class V.  Mean pre-operative GFR (99.7ml/min/1.73m2, SD 21.0) was no different to post-operative GFR (103.2ml/min/1.73m2, SD 21.3), p= 0.0861.  No patient had clinical signs of new acute renal dysfunction post-operatively. 

Four cases had  >10% decline in GFR below normal, with only one case dropping a CKD stage, from I (normal) to II (mildly decreased). 

Only 1/7 case with pre-existing renal disease had a GFR drop >10% (from 11ml/min/1.73m2 to 8ml/min/1.73m2).

70/155 (45.2%) had a temporary GFR drop post-operatively, with the biggest drop occurring a mean 3.06 days following surgery (SD 2.1). 

Conclusion: Renal function is not significantly affected by local implantation of gentamicin up to 525mg. The presence of pre-existing renal disease is not a contraindication to local gentamicin therapy.

Free papers 2a
Review of the current management of bone and joint infections within the Outpatient Parenteral Antimicrobial Therapy (OPAT) service of a large tertiary hospital in Dublin, Ireland.

Selected Abstract

Review of the current management of bone and joint infections within the Outpatient Parenteral Antimicrobial Therapy (OPAT) service of a large tertiary hospital in Dublin, Ireland.

Eileen Sweeney1, Aimee Mc Greal-Bellone1, Muhammad Muneeb Umar2, Con O’Donovan1, Colm Bergin1,3, Concepta Merry1, Brian O’Connell4, Susan Clarke1

1Department of Genito Urinary Medicine and Infectious Diseases, St. James Hospital, Dublin, Ireland. 2School of Medicine, Trinity College, Dublin, Ireland. 3. 4Department of Microbiology, St. James Hospital, Dublin, Ireland

Purpose: Bone and joint infections (BJI) require prolonged antimicrobial therapy. Although traditionally given intravenously (IV), the optimal route and duration of antimicrobial treatment are now under consideration. The aim of this review was to ascertain the current management of BJI referred to Outpatient Parenteral Antimicrobial Therapy (OPAT) in St. James Hospital (SJH), Dublin. 

Method: A retrospective review was conducted on patients referred to the OPAT programme between October 2018 – October 2019. Variables including demographics, co–morbidities, surgical intervention and antimicrobial history were collected from patient records.

Results: 81 patients were included in the study. 73 % were male, mean age of 54.7 years. The predominant site affected was the foot (23/81, 28%), 65% of whom had underlying diabetes. There was a surgical intervention in 47 of 81 (58%) patients. Targeted therapy was prescribed in 56 of 81(69%) of patients. Methicillin susceptible Staphylococcus aureus (MSSA) alone or in combination was the most commonly recovered organism (27/81, 33%). Over half of MSSA isolates were susceptible to oral antimicrobials with excellent bioavailability. At least six weeks of IV antimicrobials was prescribed in 63 of 81 (78%) patients. Ceftriaxone was most frequently prescribed IV antimicrobial 35/81(43%). Subsequent oral consolidation was prescribed in 41% of patients.

Conclusion: Most patients managed by OPAT in SJH for BJI received six weeks of IV antimicrobials in keeping with current guidelines. Over half of MSSA associated infections could have been considered for oral antimicrobials in accordance with recent clinical trials which would have a significant impact on OPAT resource utilisation.

Free papers 2a
The impact of the gentamicin-eluting injectable synthetic bone substitute, CERAMENT G, in the treatment of toe amputation for chronic bone infection at a minimum one year follow-up.

Selected Abstract

The impact of the gentamicin-eluting injectable synthetic bone substitute, CERAMENT G, in the treatment of toe amputation for chronic bone infection at a minimum one year follow-up.

Michael Field, Jamie Banks, Joshua Luck, Nicholas Ward, Alexander Wee

Frimley Park Hospital, Camberley

Purpose: To assess the impact of the gentamicin-eluting injectable synthetic bone substitute, CERAMENT G, in the treatment of toe amputation for chronic bone infection at a minimum one year follow-up.

Methods: We retrospectively reviewed all cases of toe amputation in our institution where CERAMENT G was used. We also identified a cohort of patients who underwent toe amputation for chronic bone infection where no local antibiotic eluting agent was used. Re-operation rate and evidence of local complications, including symptomatic heterotrophic ossification, were assessed in both groups.

Results: Patients undergoing toe amputation for chronic bone infection with the use of CERAMENT G demonstrated a lower re-operation rate at minimum one year follow-up with no additional adverse outcomes noted.

Conclusions: CERAMENT G demonstrates potential benefits in toe amputation for chronic bone infection at minimum one-year follow up.

Free papers 2a
Comparison of the presentation and outcomes of bacterial and tuberculous large joint infection

Selected Abstract

Comparison of the presentation and outcomes of bacterial and tuberculous large joint infection

Dr Jack Goodall, Dr Jessica Barrett, Dr Ben Patterson, Dr Matthew Colquhoun, Dr Sarah Williamson, Dr Ana Clayton-Smith, Dr Tumena Corrah

Northwick Park Hospital, London

 

Introduction: Large joint infections can lead to significant long-term morbidity, however, data regarding outcomes are limited.

Methods: We reviewed the presentation and outcomes of large joint tuberculosis infections (LJTI) and bacterial infections (LJBI) as a service evaluation. LJTI were identified via the London Tuberculosis Register (01/01/2010-01/01/2019) and LJBI via positive joint fluid samples (01/01/13-01/01/19).  Data were collected from the medical records and via telephone follow-up. Prosthetic and superficial infections were excluded.

Results: We evaluated 44 patients with LJTI and 64 patients with LJBI. The organism in LBJI were: 42.2% Staphylococcus aureus (with 11% of these being methicillin resistant); 12.5% Streptococcus pyogenes; 9.4% Escherichia coli and 6.3% Pseudomonas aeruginosa.  Other gram positives were found in 25% and other gram negative in 4.7%.

Joint fluid

TB n= 30

Bacterial n = 58

acellular

6

1

+

15

7

++

3

16

+++

3

34

Granulomata

3

0

 

Table: comparison of joint fluid aspirates

 

LJTI

LJBI

P value

n

Median (IQR)

n

Median (IQR)

WCC

43

6.9 (6.1-8.1)

60

11.7 (8.2-14.8)

<.001

Neutrophils

43

4.5 (4.0-5.7)

60

8.5 (6.5-11.4)

<.001

Lymphocytes

43

1.5 (1.1-1.8)

60

1.3 (0.8-1.7)

.121

CRP

40

24.5 (7.3-37)

61

180 (92.3-251)

<.001

ESR

30

45 (15.3-63.3)

30

56 (36.5-104.8)

<.001

Table 1: comparisons by Mann Whitney U

Following antimicrobial therapy (excluding loss to follow-up)

LJTI: (n=36)

  • 8% asymptomatic at last follow-up
  • 9% symptomatic, not requiring surgery
  • 3% underwent surgical intervention (one bone graft, one arthroplasty, one arthroscopy)
  • No deaths

LJBI: (n=43)

  • 2% asymptomatic at last follow-up
  • 6% symptomatic, not requiring surgery
  • 3% underwent surgical intervention (two arthroplasties, two arthroscopies)
  • 14% mortality

The mortality was significantly greater in the LJBI group (p=0.029 by Fisher’s exact test).

Conclusions: LJBI was associated with higher serum inflammatory marker and higher mortality rates compared with LJTI.  Post-treatment morbidity was common in both groups.

Free papers 2a
Bone and joint infections due to methicillin susceptible staphylococcus aureus bactereamia – a one year retrospective study at tertairy hospital, UHCW.

Selected Abstract

Bone and joint infections due to methicillin susceptible staphylococcus aureus bactereamia – a one year retrospective study at tertairy hospital, UHCW.

Rinku Chaurasia, Anand Deshmukh, Peter Munthali

University Hospital Coventry and Warwickshire NHS Trust, Coventry

Background: Staphylococcus aureus is recognised an important pathogen of bone and joint infections. The pattern of acute infections caused by these virulent pathogen has changed over the time.    

Aim: The study was undertaken to present the clinical characteristics, risk factors, and outcomes of patients with osteoarticular infections, associated   with Staphylococcus aureus infections. 

Method: A total of 121 patients with MSSA septicaemia between January 2019 to December 2019 were included. Demographic and clinical characteristic reviewed from the Patient information system.

Results: The primary source of infection was musculoskeletal in 31 patients (25.6%). Among these 49.1% native septic arthritis, 19.5% prosthetic joint infection ,16.2% long bone Osteomyelitis, 13% vertebral Osteomyelitis and9.6% others. The overall rate of infection was higher in males than in females with the incidence recorded highest amongst person > 65 years. several groups were identified as being at significantly higher risk for developing metastatic infections .out of 31 Patients, six had other deep seated focus such as Infective Endocarditis. Two patients (6%) with MSSA   Septicaemia died from other cause of sepsis.

Conclusion: Staphylococcus aureus bacteraemia are particularly problematic because of the high incidence of associated complicated infections. Therefore, it is important to treat vigorously at early stages to prevent furthermore complications.

Free papers 2b
Prevalence of staphylococcus aureus colonization in patients for total joint arthroplasty in South Africa

Selected Abstract

Prevalence of staphylococcus aureus colonization in patients for total joint arthroplasty in South Africa

Jurek Pietrzak, Zia Maharaj, Lipalo Mokete

Introduction: Periprosthetic joint infections (PJIs) are a major source of morbidity and mortality for patients undergoing Total Joint Arthroplasty (TJA).  Staphylococcus aureus (S aureus) colonization is an independent, modifiable risk factor for PJI. Post-operative infections are reported to be ten times greater in S aureus-carriers compared to non-carriers in developed countries however similar data is lacking for the developing world. This study aims to determine the prevalence of S aureus colonization in patients awaiting TJA in South Africa. 

Methods: We prospectively assessed 119 patients awaiting Total Knee Arthroplasty (TKA) and Total Hip Arthroplasty (THA) between May and October 2016. We screened three separate anatomical sites on each patient for S aureus. Patients with positive cultures were treated with intranasal mupirocin ointment and chlorhexidine body wash. Data was correlated with positive results and potential risk factors were evaluated. 

Results: The overall prevalence of Methicillin Sensitive S aureus (MSSA) was 31.9% (n = 38). There were no patients colonized with Methicillin Resistant S aureus (MRSA). Eradication was successful in 94.74% (n=36) after five days treatment. The overall complication rate was 7.6% (n=9). The 30-day readmission rate in the MSSA-colonized group was 7.9% (n=3) as opposed to 7.4% (n=6) in the non-colonized cohort. No cases were revised at a mean follow-up of 2.26 years.

Conclusions: The prevalence of S aureus in TJA patients in South Africa is equivalent to reported data from developed countries. A larger cohort of patients is recommended to determine risk factors and post-operative septic sequelae in this population group.

Free papers 2b
Necrotizing Fasciitis – an experience in a UK District General Hospital

Selected Abstract

Necrotizing Fasciitis – an experience in a UK District General Hospital

Kawaljit Dhaliwal1, Rajesh Bawale2, Srinivaso Samsani1

1Medway Maritime Hospital, Gillingham, United Kingdom. 2Medway maritime Hospital, Gillingham                                           

Background: Necrotizing fasciitis (NF) is life/limb threatening condition that results in gross morbidity and mortality if not treated in its early stages. However, on onset, it is difficult to differentiate from other superficial skin conditions such as cellulitis, bruising secondary to the trauma. In this case series we aim to review the clinical presentation of Necrotising fascitis orthopaedic cases, the role of early diagnosis to assess the PPV of the LRNEC score in cases proven to need urgent surgical intervention.

Methods: The data was collected prospectively and retrospectively from computerised and file records of 16 consecutive patients who have been admitted in our hospital. When clinical assessment and surgical exploration were equivocal, the final diagnosis of NF in our study was made based on confirmatory histopathologic analysis. LRNEC score was calculated at presentation. 

Results: The results collected for each of the 16 patients were age, gender, pre- disposing factors, presenting signs and symptoms, location of infection, laboratory findings, microbiological cultures, the type of therapy used, treatment outcome and number of days in the hospital. Patient age ranged from 30 to 77 years (average age 54.6). In our case series, we noted streptococcal is the commonest pathogen found in 9 cases, staphylococcus was seen in 4 cases, 2 cases had serretia marcescens and mixed anaerobes noted in 1 case.  PPV for LRNEC was 96%. 

Conclusion:   We strongly recommend high clinical suspicion, prompt investigations and resuscitation with appropriate antimicrobial therapy followed by expedited surgical debridement to reduce the morbidity and mortality.                          

Abstract without diagnosis

 Background: This is a life/limb threatening condition that results in gross morbidity and mortality if not treated in its early stages. However, on onset, it is difficult to differentiate from other superficial skin conditions such as cellulitis, bruising secondary to the trauma. In this case series we aim to review the clinical presentation of this condition in orthopaedic cases, the role of early diagnosis to assess the PPV of the LRNEC score in cases proven to need urgent surgical intervention.

Methods: The data was collected prospectively and retrospectively from computerised and file records of 16 consecutive patients who have been admitted to our hospital. When clinical assessment and surgical exploration were equivocal, the final diagnosis in our study was made based on confirmatory histopathologic analysis. LRNEC score was calculated at presentation.

Results: The results collected for each of the 16 patients were age, gender, pre- disposing factors, presenting signs and symptoms, location of infection, laboratory findings, microbiological cultures, the type of therapy used, treatment outcome and number of days in the hospital. Patient age ranged from 30 to 77 years (average age 54.6). In our case series, we noted streptococcal is the commonest pathogen found in 9 cases, staphylococcus was seen in 4 cases, 2 cases had serretia marcescens and mixed anaerobes noted in 1 case.  PPV for LRNEC was 96%.

Conclusion:   We strongly recommend high clinical suspicion, prompt investigations and resuscitation with appropriate antimicrobial therapy followed by expedited surgical debridement to reduce the morbidity and mortality 

Free papers 2b
Debridement, Antibiotics and Implant retention (DAIR) following total hip and knee replacements: a DGH experience

Selected Abstract

Debridement, Antibiotics and Implant retention (DAIR) following total hip and knee replacements: a DGH experience

Fady Awad, Salim Punjabi, Kodali Prasad, Chanaka Silva, Stephen Sarasin, Peter Lewis

Prince Charles Hospital, Merthyr Tydfil

Introduction: The gold standard management for a prosthetic joint infection (PJI) is a two stage revision procedure. However, if a PJI is diagnosed promptly a debridement, antibiotics and implant retention (DAIR) procedure can be performed. We report the results of our experience with the DAIR procedure in a District General Hospital.

Methods: This is a single centre retrospective review of a prospectively updated database. All patients who underwent a DAIR procedure following a total hip or knee replacement from August 2012 to July 2019 were included in the study with no exclusions. 

Results: Four total knee replacements, fifteen total hip replacements, two revision total hip replacements and three hemiarthroplasties were included in the study. Average duration from onset of symptoms to the DAIR procedure was 10 days. All patients had exchange of modular components during the DAIR procedure. Staphylococcos aureus (23%) and staphylococcus epidermidis (23%) were the most common causative organisms and the most common antibiotic regimens included intravenous teicoplanin (54%) and flucloxacillin (16%). Average follow up in clinic was 48 months. 80% of patients had a stable post-operative recovery with no recurrence of infection. One patient required a revision total hip replacement for aseptic loosening; one patient required a knee arthrodesis and three patients died.

Conclusion: This mid term study with mean follow up of 48 months from a DGH setting presents the outcome of 24 DAIR procedures. Positive cultures were identified in 22 cases, infection was successfully eradicated in 19 patients and 2 patients required revision surgery. 

Free papers 2b
Management of Fracture Related Infections (FRIs) at a Local DGH against British Orthopaedic Association Standards for Trauma (BOAST) guidelines.

Selected Abstract

Management of Fracture Related Infections (FRIs) at a Local DGH against British Orthopaedic Association Standards for Trauma (BOAST) guidelines.

Ibrahim Jaly, Muyed Mohamed, Francis Ezegbe, David Selvan

Southport & Ormskirk Hospital NHS Trust, Southport

 

Introduction: Poor management of fracture related infections can have a significant impact on patient outcomes and on the associated morbidity and mortality. This in turn has an associated adverse impact for NHS Trusts in relation to length of stay & cost of treatment.We aim to assess our practice in identifying & managing fracture related infections(FRIs) as compared to the new BOAST guidelines. 

Method: This was a retrospective study. We identified patients presenting to Southport District General Hospital with a post-operative infection following fracture fixation between September 2018 – September 2019. Clinical notes, pathology and imaging results were reviewed.

Results: 16 patients were identified after developing a FRI.The cohort included 7 hip fractures, 3 olecranon fractures, 2 clavicle, 2 ankle, 1 forearm and 1 foot fracture. Identification/work-up: Only 40% of septic patients had a medical review. 82% of septic patients had blood cultures. 94% of all cases had plain radiographs taken and 12% had their wound photographed. 

Managment: 82% had i.v antibiotics without delay.100% of patients with a FRI were discussed at a bone & joint infection MDT. 88% required at least 1 return to theatre.There were 3 mortalities.

Conclusions: This study demonstrates that fracture related infections are a serious complication of surgical fixation; with a high return to theatre rate (88%) and resulting in 3 fatalities in our unit. Following this audit we have implemented a management flow chart for use in A&E to improve our practice. This includes expert advice from Tissue Viability and Microbiology teams regarding wound management and Antibiotic choice. 

Free papers 2b
The role of a labelled white cell scan in diagnosing periprosthetic joint infections following knee arthroplasty: a retrospective analysis from a high volume tertiary revision unit

Selected Abstract

The role of a labelled white cell scan in diagnosing periprosthetic joint infections following knee arthroplasty: a retrospective analysis from a high volume tertiary revision unit

Samuel Trowbridge, Anita Ofori, Jack Kingdon, Mohit Bansal, Raghbir Khakha, Adil Ajuied, James Bliss, Peter Earnshaw, Diane Back, Carolyn Hemsley, Philip Pastides

Guy’s and St Thomas’ NHS Foundation Trust, London

Purpose: The role of a labelled white cell scans to help diagnose a peri-prosthetic joint infection (PJI) in the painful knee arthroplasty remains unclear. The International Consensus Meeting (ICM) criteria represent an accepted method of defining the presence of a PJI. This retrospective study assesses the diagnostic accuracy of labelled white cell scans when compared to the ICM criteria.

Methods: All patients over a 72-month period in a high-volume tertiary knee revision unit, in whom a labelled white cell scan was performed, were retrospectively analysed. The interpretation of these scans was compared to the ICM criteria for a diagnosis of a PJI.

Results: Ninety-one scans were performed in total. Of these, 18 (19.8%) were subsequently diagnosed and treated for a PJI. Only 3 of the 91 scans (3.2%) were interpreted as diagnostic of a PJI; however all 3 patients were from the group of 18 who were treated for a PJI. Fifteen of the 91 scans (16.5%) were interpreted as inconclusive, whilst 73 scans (80.2%) were interpreted as showing no signs of a PJI. Our results shows that as an adjunct to diagnosing a PJI, a labelled white cell scan has a sensitivity of 16.7%, a specificity of 100%, a positive predictive value of 100% and a negative predictive value of 85.4%.

Conclusion: Labelled white cell scans have a limited role in diagnosing a PJI; this should still be made according to the ICM criteria. These scans may not represent a cost-effective modality and interpretation should be treated with caution.

Free papers 2b
A service evaluation into the outcomes of periprosthetic joint infections in total hip replacements and total knee replacements

Selected Abstract

A service evaluation into the outcomes of periprosthetic joint infections in total hip replacements and total knee replacements

Ismail Saddaoui1, Aaron Yeung1, Edward Gardner2, Kordo Saeed2

1University of Southampton, Southampton. 2University Hospital Southampton, Southampton

Background: Total Hip Replacement (THR) and Total Knee Replacement (TKR) are staple procedures for end-stage arthritis and/or trauma in the young and elderly. One serious complication of these procedures is Peri-prosthetic Joint Infection (PJI) which is both equally difficult to diagnose and treat. Treatments vary from antibiotic administration to revision surgery (Debridement Antibiotics and Implant Retention [DAIR], One-stage or Two-stage) or a combination of both.

 

Aims: To evaluate and examine the microbiological and surgical treatment options and outcomes for treating PJIs at the University Hospital Southampton (UHS) compared to existing literature.

 

Methods: Patients with PJI infections of THR or TKR were identified from an infection database, referred to microbiology from the Trauma and Orthopaedics department. A total of 124 patient were identified with only 112 patients satisfying the inclusion criteria. A qualitative measure was also enlisted through the Oxford Score (Knee and Hip) used as a secondary outcome measure.

 

Results: 112 patients were included in the study with the mean age being 73 years old at patients’ latest operation. Of these, 38 had infected THR while 74 had infected TKR. 61% of THR were cured after initial treatment procedure while only 47% of TKR were cured. There was no significant different in treatment outcome of giving one intervention, be it surgical or pharmacological (i.e. antibiotics), over multiple. Three patients had an amputation after failed multiple revisions. Out of all the treatment modalities two-stage revision showed the most promising cure of infection with a success-rate of 77% (n=58)

Best Free Papers
The use of primary implants for revision of the infected total knee replacement: good short- to mid- term results with significant cost saving

Selected Abstract

The use of primary implants for revision of the infected total knee replacement: good short- to mid- term results with significant cost saving

Ashley Brown, Simon Lewthwaite, Robin Banerjee, Niall Graham, Richard Spencer Jones, Christopher Evans

The Robert Jones and Agnes Hunt Orthopaedic Hospital, Oswestry

 

Purpose: We report on the outcomes of revision of infected total knee replacements (TKR) using primary implants.

Methods: We performed a retrospective observational study of patients who underwent revision TKR for infection using primary implants. 20 patients underwent revision of both femoral and tibial components using the Medial Rotating Knee (MRK) prosthesis (MatOrtho, Surrey, UK). Oxford Knee Scores (OKS) were obtained pre- and post-operatively. Survivorship was assessed using Kaplan-Meier survival curves. Cost analysis was performed and compared to the total cost of the most commonly used revision construct at our institution in “like-for-like” revision cases.

Results: 20 patients underwent revision TKR for infection; 17 of these cases satisfied the 2018 ICM criteria for prosthetic joint infection, with the remaining 3 being treated as infection despite not satisfying the criteria. 18 knees (90%) underwent a 2 stage procedure whereas 2 knees (10%) underwent single stage revision. 3 patients died in the follow up period at a mean of 1.7 years post-op. Median OKS improved from 11.5 to 32.5 (IQR 21.5 – 39.3) at a mean of 5.0 years post-op (p<0.05). 5 year survivorship was 100%.

The use of primary implants resulted in an average implant costs saving of 52% per case.

Conclusions: The use of primary, stemmed implants, such as the MRK, can be safely used in the management of infected TKR. This small case series has demonstrated significant improvement in patient reported outcomes and excellent survivorship.

Best Free Papers
Inferior accuracy of serum inflammatory markers in diagnosing fracture related infections

Selected Abstract

Inferior accuracy of serum inflammatory markers in diagnosing fracture related infections

Irene Katharina Sigmund1,2, Mario Morgenstern3, Maria Dudareva2, Nicholas Athanasou2, Martin McNally2

1Medical University of Vienna, Vienna, Austria. 2Nuffield Orthopaedic Centre, Oxford. 3University Hospital Basel, Basel, Switzerland

Objectives: In this retrospective study, the accuracy of serum inflammatory markers in the diagnosis of fracture related infections (FRI) defined by the FRI Consensus Definition was analysed. 

Methods: Serum CRP, leukocyte count (WBC), and differential were measured preoperatively in 106 patients having surgery for suspected FRI. The cut-offs of >5 mg/L for CRP, >10×10^9 cells/L for WBC, >70% for the percentage of neutrophils (%N), and >3 for the neutrophils to lymphocytes ratio (NLR) were regarded as positive for infection. Accuracy was determined using ROC and a simple decision tree constructed.

Results: 46 patients (43%) had a confirmed FRI. Sensitivity, specificity, and AUC of serum CRP were 67% (52 –80%), 61% (47 – 74%), and 0.64 (0.54 –0.74); of serum WBC count 17% (9-31%), 95% (86 -99%), and 0.57 (0.50 – 0.62); of %N 13% (6 – 26%), 87% (76 -93%), and 0.50 (0.43 – 0.56); and of NLR 28% (17 – 43%), 80% (68 -88%), and 0.54 (0.46 – 0.63). CRP showed a better performance in comparison to WBC (p=0.006), %N (p<0.0001), and NLR (p=0.001).  A simple decision tree approach using neutrophils (<3.165×10^9/L) and CRP (<2.45 mg/L) may allow exclusion of infection.

Conclusion: All serum inflammatory parameters showed insufficient accuracy. Although CRP had a better accuracy compared to the other markers, performance was only moderate. Hence, these parameters should only be suggestive tests in diagnosing FRI. The simple decision tree using CRP and neutrophils may allow detection of a proportion of uninfected cases.

Best Free Papers
Superiority of combined antibiotic therapy spacers – a microbiological analysis at the second stage of revision

Selected Abstract

Superiority of combined antibiotic therapy spacers – a microbiological analysis at the second stage of revision

André Dias Carvalho, Ana Ribau, Tiago Amorim Barbosa, Miguel Abreu, Daniel Esteves Soares, Ricardo Sousa

Centro Hospitalar e Universitário do Porto, Porto, Portugal

Antibiotic loaded spacers are often used during two-stage exchange for periprosthetic joint infections (PJI). 

Our goal is to compare the efficacy of different antibiotic(s) in spacers concerning the rate of positive cultures at the second stage.

We evaluated two-stage exchange procedures at our hospital for infected arthroplasty between 2012-2018. Microbiological findings were registered as the spacer and antibiotic(s), time between stages, duration of systemic antibiotic, and if the surgeries were performed by dedicated septic surgeon. 

58cases (22THA&36TKA) with an overall rate of positive cultures during reimplantation of18.9%(11/58). Univariable analysis suggested combined antibiotic(s) in the spacer, shorter interval between stages and dedicated septic surgeon to be significant predictors. The rate of positive cultures was significantly higher among monotherapy spacers compared to spacers with combined therapy (vancomycin+gentamicin with/without carbapenem)-40.0%(6/15)vs.11.6%(5/43) respectively(p=0.016). Multivariate analysis showed combined therapy was the only independent risk factor (p=0.049,OR:2.5).There weren’t significant differences comparing vancomycin/gentamicin(2/19)vs vancomycin/meropenem/gentamicin spacers(3/21). The necessity for subsequent surgery was significantly higher-63.6%(7/11) in cases with positive cultures compared to 4.3%(2/47) for those with negative cultures(p<0.001).Microorganisms present during the reimplantation were mostly staphylococci(9/11-the same as the first stage) and resistant to the antibiotic(s) used in the spacer(7/9 cases).

Positive cultures during second stage reimplantation have been shown to increase the risk of subsequent failure as was the case in our series. The combination of antibiotic in spacers are advantageous compared to monotherapy.

Best Free Papers
No joint destruction in patients with prolonged septic arthritis induced by a communicating intraosseous abscess.

Selected Abstract

No joint destruction in patients with prolonged septic arthritis induced by a communicating intraosseous abscess.

Anna Bertoli Borgognoni, Martin Gottliebsen, Klaus Kjær Petersen

Department of Orthopaedic Surgery, Aarhus University Hospital, Aarhus, Denmark

Background: Septic arthritis demands prompt intervention due to risk of cartilage destruction when treatment is delayed. 

Aim of study: We present seven cases of septic arthritis in combination with a communicating intraosseous abscess. Our goal was to assess the impact on the affected joints.

Materials and Methods: Seven male patients with median age 4 (range; 1-22) years, were identified in a period from 2010 to 2018. Data from journals, radiology, blood samples and cultures were retrospectively collected.

Results: All patients presented with a history of minor pain from affected joints as well as subfebrilia and discomfort. Median treatment delay was 2 months (range; 1 day-12 months). 

None of the patients were septic at admission, and median CRP was 30 (2-102 mg/L).

Knee joint was involved in 5 cases and further 2 cases affecting elbow- and subtalar joints respectively.

Radiographs and MRI showed juxta-articular intraosseous abscess communication into the joint with effusion, synovitis and revealed no evidence of joint destruction.

3 patients were treated with arthroscopic synovectomy and debridement of the abscess, 3 were treated with just debridement and washout of the joint, one with open synovectomy. 

Biopsies were taken from abscesses and synovia: Staph. aureus was responsible for 3 cases, Salmonella for one, and the remaining 3 cases had negative cultures. 

All patients received antibiotics for 6 weeks.

Conclusions: Patients with septic arthritis due to a communicating intraosseous abscess seem to avoid joint destructions even in situations with considerable therapeutic delay.

Best Free Papers
There is a low rate of infections and subsequent 30 and 60-day admission rates in primary hip arthroscopy, revision hip arthroscopy, and cases converted to total hip arthroplasty.

Selected Abstract

There is a low rate of infections and subsequent 30 and 60-day admission rates in primary hip arthroscopy, revision hip arthroscopy, and cases converted to total hip arthroplasty.

Wesley Verhoogt1, Jurek Pietrzak1, Kathleen Nortje2, Josip Cakic2

1University of the Witwatersrand, Johannesburg, South Africa. 2Centre for Sports Medicine and Orthopedics, Fourways Life Hospital, Johannesburg, South Africa

Introduction: The incidence of hip arthroscopy (HA) has increased exponentially worldwide. Superficial infection complicates 0.3% of cases. However, complication rates may be under-estimated in the literature. The aim of this paper was to determine the incidence of infective complications in primary HA, revision HA and conversion total hip arthroplasty (cTHA).

Methods: We conducted a retrospective chart review of all patients who underwent HA by a single high-volume surgeon from 2012-2018. The incidence of all complications and readmission rates were documented. All patients had an MRI arthrogram performed within 30 days prior to HA.  All revision HA and cTHA had aspirate fluid sent for microscopy, culture and sensitivity (MC&S). All cases received pre-operative antibiotics.

Results: A total sample of 880 HA in 646 patients, 100(11.3%) of these being revision HA and 25(2.8%) cTHAs. The overall complication rate after HA was 4.3%(n=38). Primary HA, revision HA and cTHA were complicated by superficial infections in 0,2%(n=2), 0.1%(n=1) and 0% respectively. There was no growth on MC&S from specimens taken at any revision HA or cTHA. There were no infective complications in any cTHA. No deep infections were reported in any cases. All infections were treated successfully with oral antibiotics. 

Conclusion: MRI arthrogram does not predispose infective complications. Primary HA and revision HA have a low superficial infection rate. Primary HA, revision HA and cTHA do not predispose to infective complications or increased 30-or 60-day readmission rates provided prophylactic antibiotics are prescribed and appropriate precautions are followed.

Best Free Papers
Humanized mice exhibit increased susceptibility to Staphyloccocus aureus osteomyelitis-induced bacteraemia

Selected Abstract

Humanized mice exhibit increased susceptibility to Staphyloccocus aureus osteomyelitis-induced bacteraemia

Eric Sumrall1, Wallimann Alexandra1, Maria Hildebrand1, Stephan Zeiter1, Geoff Richards1, Edward Schwarz2, Fintan Moriarty1, Gowrishankar Muthukrishnan2

1AO Research Institute Davos, Davos, Switzerland. 2Department of Orthopaedics, Center for Musculoskeletal Research, Rochester, NY, USA

 

Osteomyelitis presents a significant barrier to the successful treatment of fracture-related repair and peri-prosthetic joint infection. Despite the breadth of current standard treatments, outcomes remain relatively poor, largely due to the unique abilities of Staphylococcus aureus to establish infection within the human host. Immune therapy towards S. aureus presents a highly desirable treatment option, but many attempts to produce an effective vaccine have failed. As the unique specificity of S. aureus as a human pathogen continues to come to light, it becomes clear that reliance on murine models may have contributed to previous failures in vaccine development. To address this, we here present a humanized mouse model of osteomyelitis. Immunodeficient non-obese diabetic (NOD)–scid IL2Rγnull (NSG) mice are engrafted with CD34+ human hematopoietic stem cells and subjected to MRSA osteomyelitis via a contaminated transtibial pin. Relative to their infected WT and immunocompromised counterparts, humanized mice present with several unique characteristics: namely the increased formation of Staphylococal abscess colonies (SACs), extensive osteolysis, and increased hematogenous dissemination of bacteria to distant organs. Strikingly, infection severity correlated inversely with human T-cell numbers, suggesting that T-cell responses may play a role in suppressing the spread of infection in this unique model. 

Best Free Papers
Prescribing practice post OVIVA: What are we doing now?

Selected Abstract

Prescribing practice post OVIVA: What are we doing now?

Ruth Corrigan1,2, Claire Scarborough1, Robert Shaw1, Esmie Warne1, Martin McNally1, Matthew Scarborough1

1Bone Infection Unit, Nuffield Orthopaedic Centre, Oxford University Hospitals, Oxford. 2Nuffield Department of Clinical Laboratory Sciences, Oxford University, Oxford

The OVIVA trial demonstrated that oral antibiotic therapy is non-inferior to intravenous antibiotic therapy when used during the first 6 weeks for complex orthopaedic infection as measured by treatment failure at one year (Li, 2019). 

The current study reports the antibiotic choices for patients with bone and joint infection who were discharged from the Bone Infection Unit in Oxford on >4 weeks of therapy in the 6 months following the publication of OVIVA.

Of 156 patients, 100 (64.1%) were male, and the average age was 61.4 years (range 49.3-75). 137 (87.8%) patients were discharged on oral antibiotics.  

Ciprofloxacin was the most commonly prescribed oral antibiotic agent (33.8% of all oral prescriptions), followed by clindamycin (14.9%) and doxycycline (11.9%). Adjunctive rifampicin was used in 28% of oral prescriptions, most often in combination with ciprofloxacin. Rifampicin use was most commonly included in Staphylococcal infections and when metal work was left in situ.

The most common explanation for use of IV antibiotics was lack of viable oral option (12/19 patients (63%)). By pathogen, Enterococcal infections were most often treated with intravenous antibiotics (31% of infections) whereas all Staphyloccoccus aureus infections were treated with oral options.

In summary, following the publication of the OVIVA trial, nearly 90% of patients with bone and joint infection discharged from the BIU, Oxford, were discharged with oral antibiotics. Rates of use of intravenous antibiotics and choice of oral agent varied by pathogen isolated. Overall, ciprofloxacin (with or without adjunctive rifampicin) was the most commonly prescribed oral agent. 

Best Free Papers
Prescribing practice post OVIVA: What are we doing now?

Selected Abstract

Prescribing practice post OVIVA: What are we doing now?

Ruth Corrigan1,2, Claire Scarborough1, Robert Shaw1, Esmie Warne1, Martin McNally1, Matthew Scarborough1

1Bone Infection Unit, Nuffield Orthopaedic Centre, Oxford University Hospitals, Oxford. 2Nuffield Department of Clinical Laboratory Sciences, Oxford University, Oxford

The OVIVA trial demonstrated that oral antibiotic therapy is non-inferior to intravenous antibiotic therapy when used during the first 6 weeks for complex orthopaedic infection as measured by treatment failure at one year (Li, 2019). 

The current study reports the antibiotic choices for patients with bone and joint infection who were discharged from the Bone Infection Unit in Oxford on >4 weeks of therapy in the 6 months following the publication of OVIVA.

Of 156 patients, 100 (64.1%) were male, and the average age was 61.4 years (range 49.3-75). 137 (87.8%) patients were discharged on oral antibiotics.  

Ciprofloxacin was the most commonly prescribed oral antibiotic agent (33.8% of all oral prescriptions), followed by clindamycin (14.9%) and doxycycline (11.9%). Adjunctive rifampicin was used in 28% of oral prescriptions, most often in combination with ciprofloxacin. Rifampicin use was most commonly included in Staphylococcal infections and when metal work was left in situ.

The most common explanation for use of IV antibiotics was lack of viable oral option (12/19 patients (63%)). By pathogen, Enterococcal infections were most often treated with intravenous antibiotics (31% of infections) whereas all Staphyloccoccus aureus infections were treated with oral options.

In summary, following the publication of the OVIVA trial, nearly 90% of patients with bone and joint infection discharged from the BIU, Oxford, were discharged with oral antibiotics. Rates of use of intravenous antibiotics and choice of oral agent varied by pathogen isolated. Overall, ciprofloxacin (with or without adjunctive rifampicin) was the most commonly prescribed oral agent. 

Posters

Reducing Implant Infection in Orthopaedics (RIIiO)

Selected Poster

Reducing Implant Infection in Orthopaedics (RIIiO)

Michelle Kümin1, Chris Jones2, Stephen Bremner2, Andrew Smith3, Mark Dunbar4, Oliver Pearce5, Jillian Hewitt-Gray6, Nicky Perry7, Christopher Mark Harper2,7, Mike Reed8, Matthew Scarborough9

1Nuffield Department of Medicine, University of Oxford, Oxford
 2Brighton and Sussex University Hospitals NHS Trust, Brighton
 3East Kent Hospitals University NHS Foundation Trust, Margate
 4Heart of England NHS Foundation Trust, Solihull
5Milton Keynes University Hospitals NHS Foundation Trust, Milton Keynes
 6Oxford University Hospitals NHS Foundation Trust, Banbury
7Brighton and Sussex Medical School, Brighton
8Northumbria Healthcare NHS Foundation Trust, North Shields
9Oxford University Hospitals NHS Foundation Trust, Oxford

Surgical site infection (SSI) is a serious complication of joint replacement surgery. Inadvertent perioperative hypothermia is a risk factor for SSI. There is some evidence that Forced Air Warming (FAW) to maintain normothermia may negate the protective effects of laminar airflow ventilation. Resistive Fabric Warming (RFW) does not interfere with laminar flow. A randomised trial to compare SSI rates following warming with FAW or RFW would require approximately 10,000 participants. We have conducted a pilot study in the first instance to confirm recruitment capacity.

In a parallel group, open label trial, adults undergoing hemiarthroplasty following hip fracture were randomised to either FAW or RFW. Hypothermia at the end of surgery was defined as <36°C. Participants were followed up at three months for deep SSIs as determined by an independent, blinded endpoint committee. Secondary endpoints included superficial SSIs and serious adverse events.

515 participants were recruited. No unexpected and related serious adverse events were reported and there was no difference in the mean temperature before anaesthesia, during surgery, at the end of surgery or upon arrival in the recovery room.   Deep SSIs were confirmed in both arms. The overall incidence of deep SSI was 1.6% which was lower than previously reported.

The pilot study demonstrated robust recruitment and data management strategies and shown that FAW and RFW were both safe to use and effective at maintaining normothermia. There was insufficient power in the pilot study to compare the number of infections. Funding for a full trial is now sought.

Resistive fabric warming as a viable alternative to forced air warming for maintaining normothermia to prevent surgical site infection

Selected Poster

Resistive fabric warming as a viable alternative to forced air warming for maintaining normothermia to prevent surgical site infection

Michelle Kümin1, Chris Jones2, Alex Woods3, Stephen Bremner2, Mike Reed4, Matthew Scarborough5, Christopher Mark Harper2,6

1Nuffield Department of Medicine, University of Oxford, Oxford
2Brighton and Sussex University Hospitals NHS Trust, Brighton
3Milton Keynes University Hospitals NHS Foundation Trust, Milton Keynes
4Northumbria Healthcare NHS Foundation Trust, North Shields
5Oxford University Hospitals NHS Foundation Trust, Oxford
6Brighton and Sussex Medical School, Brighton

Inadvertent perioperative hypothermia can have severe consequences. Active warming to maintain normothermia can help to prevent surgical site infection. However, core temperature measurement during anaesthesia is not standardised and the best warming method to use during orthopaedic surgery is debatable. The primary objective of this analysis was to compare temperatures during surgery between two types of patient warming.

Temperature readings measured using zero-flux thermometry were compared in participants recruited to a randomised pilot study comparing post-operative infection rates using Forced Air Warming (FAW) or Resistive Fabric Warming (RFW). Temperatures were taken after induction of anaesthesia and at 5-minute intervals during surgery. The groups were compared using regression models with fixed effects for trial group and covariates related to temperature.

There was no evidence of a difference in the proportion of hypothermic patients during surgery or at the end of surgery, whether hypothermia was defined as <36.5°C or <36.0°C, and there was no evidence of a difference in time from surgery to discharge, between the RFW and FAW groups; the overall median time to discharge was 14 days in both groups. Those in the RFW group were -0.08°C (95% CI: -0.15 to -0.01) cooler than those in the FAW group and had a cumulative hypothermia score -1.87 lower than the FAW group (95% CI: -3.31 to -0.42; P=0.012). The implication of these differences is uncertain but that may not be clinically important.

This comparison has shown that FAW and RFW are similarly effective in preventing inadvertent perioperative hypothermia.

Preference for forced air warming to prevent inadvertent perioperative hypothermia

Selected Poster

Preference for forced air warming to prevent inadvertent perioperative hypothermia

Michelle Kümin1, Matthew Scarborough2

1Nuffield Department of Medicine, University of Oxford, Oxford
2Oxford University Hospitals NHS Foundation Trust, Oxford

Preventing inadvertent perioperative hypothermia (IPH) during surgery decreases rates of wound infection, cardiovascular events, perioperative pain, bleeding, duration of surgery and total duration of hospital stay. The aim of this survey was to see if there is a user preference.

Staff involved in the RIIiO trial were asked about the using Forced Air Warming (FAW) and Resistive Fabric Warming (RFW). All 16 respondents (7 nurses, 6 ODPs, 2 surgeons, 1 anaesthetist) were experienced FAW users; there was an equal number of experienced and inexperienced RFW users.

No difference was observed in how easy the two technologies are to operate, access to the surgical site or how they adapt to the patient’s body shape. FAW was marginally better than RFW for draping over the patient and considerably better for storing when not in use. Few respondents found the heat generated by FAW uncomfortable and none mentioned the noise generated.

The majority of respondents believed that FAW and RFW were equally safe to use and that RFW was more economical in the long term but that FAW was quicker at warming the patient. Almost all of the respondents were confident that cleaning was adequate in terms of infection control for both systems. Nearly half of the respondents had no overall preference; of those that did, FAW was preferred but five out of six were inexperienced RFW users.

User preference appears to be connected to level of experience. Although RFW was thought to be equally safe to use, it was not recommended.

The importance of specific timed intervention and involvement of a multi-disciplinary team when treating patients with a prosthetic joint infection

Selected Poster

The importance of specific timed intervention and involvement of a multi-disciplinary team when treating patients with a prosthetic joint infection

Claire McMahon

The Royal Orthopaedic Hospital NHS Trust, Birmingham

Introduction: In England and Wales there are approximately 187,000 total hip or knee replacement procedures performed each year. Prosthetic joint infection (PJI) remains one of the most serious complication with between 1-2% of these patients being affected. 

The authors trust carries out many revision surgeries for prosthetic joint infection each year. This poster will discuss the trust best approach to manage and support these patients.

Method: This poster will look at how the author’s trust manages patients through its Bone Infection Service (BIS). 

An MDT approach is recommended by many authors when diagnosing and treating these patients to give the best outcomes. The poster will identify current MDT roles involved in the BIS, and their contribution to MDT meetings. The role of the BIS nurse is also explored as this role is uncommon within most trusts.

Patient management is also discussed following evidence based criteria. Specifically looking at Identification of PJI, timing of intervention, BI MDT discussions, antibiotic management and discharge follow up.  

Results: The benefits to this MDT approach and specific timed intervention at the described hospital have been associated with positive patient experiences, earlier patient discharge, earlier identification of issues that require re-admission, and improved antimicrobial stewardship.

Discussion: The poster will discuss the importance of timed intervention within patient pathway and MDT involvement for patients who are undergoing treatment at named trust for a bone infection.

Man’s best friend? A septic consequence of puppy love.

Selected Poster

Man’s best friend? A septic consequence of puppy love.

Sarah Kennedy, Katharine Scott, Lauren Heath, Richard Hobson, Jennifer Child

Harrogate and District NHS Foundation Trust, Harrogate

A 66 year old man with diabetes presented with fever and a swollen, painful native left knee.  Inflammatory markers were raised (white cell count 17 x 109/L, C-reactive protein 303 mg/L). Both synovial aspirate and blood culture revealed Gram negative bacilli and he was commenced empirically on intravenous cefuroxime.  The synovial aspirate grew Pasteurella multocida. Surprisingly, the blood culture isolated Salmonella sp later identified as Salmonella enteritidis. Antibiotics were changed to intravenous amoxicillin to cover both organisms. A week later and following two washout procedures his left leg remained swollen, red and tender. MRI showed osteomyelitis of the distal femur and proximal tibia, a large collection in the quadriceps, multiple fluid collections and abscesses in the lower leg. Samples from incision and drainage of thigh and calf and a third knee washout grew Pasteurella multocida.  Amoxicillin dose was increased from 1 gram TDS to QDS. Further debridement and washout procedures were needed to control the infection. This is a case of aggressive Pasteurella bone and joint infection. It is likely that both Pasteurella and Salmonella were acquired from contact with his dog who he reported licking an open wound on his foot.  Most cases of Pasteurella bone or joint infection are due to direct inoculation or contiguous spread from skin infection.  Haematogenous spread, as we presume in this case because the site of infection is distant to the site of the animal contact, is less common.  Diabetes is a risk factor for both invasive Salmonella and Pasteurella infection.

Abstract without diagnosis

A 66 year old man with diabetes presented with fever and a swollen, painful native left knee.  Inflammatory markers were raised (white cell count 17 x 109/L, C-reactive protein 303 mg/L). Both synovial aspirate and blood culture revealed Gram negative bacilli and he was commenced empirically on intravenous cefuroxime.  The synovial aspirate grew X. Surprisingly, the blood culture isolated Salmonella sp later identified as Salmonella enteritidis. Antibiotics were changed to intravenous amoxicillin to cover both organisms. A week later and following two washout procedures his left leg remained swollen, red and tender. MRI showed osteomyelitis of the distal femur and proximal tibia, a large collection in the quadriceps, multiple fluid collections and abscesses in the lower leg. Samples from incision and drainage of thigh and calf and a third knee washout grew X.  Amoxicillin dose was increased from 1 gram TDS to QDS. Further debridement and washout procedures were needed to control the infection. This is a case of aggressive X bone and joint infection. It is likely that both X and Salmonella were acquired from contact with his dog who he reported licking an open wound on his foot.  Most cases of X bone or joint infection are due to direct inoculation or contiguous spread from skin infection.  Haematogenous spread, as we presume in this case because the site of infection is distant to the site of the animal contact, is less common.  Diabetes is a risk factor for both invasive Salmonella and X infection.

Waiting for infected hip revision surgery; exploring patient and families’ experience of waiting

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Waiting for infected hip revision surgery; exploring patient and families’ experience of waiting

Katy Crick, Swee Hwa Chin, Fiona Fitzgerald, Suzanne Bench

Royal National Orthopaedic Hopsital, London

Background: As a tertiary center for complex orthopaedic surgery, evaluating current practice is vital to enhance pathways of care. A vital element of this is to understand service users’ perspectives and experiences, yet little research to date has explored experiences of waiting in this cohort.

Objectives: To understand patients’ and families’ experiences of waiting for hip revision surgery and their perceptions of its impact on their quality of life.  

Design and Methodology: A mixed method study collected data via a survey and individual interviews from people with an infected prosthetic joint who were or who had experienced waiting for surgery between 01.05.2018 and 30.04.2019. Of the 54 participants invited to participate, 22 returned a questionnaire and six agreed to be interviewed. Quantitative data were analysed descriptively whilst qualitative data underwent thematic analysis. 

Results: Although 67% respondents reported being satisfied with their waiting time, all reported an increase in pain whilst waiting and 60% stated that waiting had a significant effect on their lives and those of their friends/family (85%). Most Respondents reported high levels of satisfaction with the support (89%) and information (83%) provided by the clinical team. Qualitative data are currently undergoing analysis 

Discussion/Conclusion: Despite Satisfaction with support and information being rated highly, waiting for surgery clearly has a great impact on patients and their families. Further understanding of this impact and how it can be mitigated is expected from the qualitative findings. 

Assessing the elution kinetics of vancomycin and tobramycin from antibiotic-loaded calcium sulfate, PMMA spacers and powdered antibiotic bolus using a reactor flow system.

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Assessing the elution kinetics of vancomycin and tobramycin from antibiotic-loaded calcium sulfate, PMMA spacers and powdered antibiotic bolus using a reactor flow system.

Craig Delury1, Devendra Dusane2, Casey Peters2, Jack Brooks2, Kelly Moore2, Phillip Laycock1, Rebecca Wilson-van Os1, Sean Aiken1, Anne Sullivan2, Jeffrey Granger2, Paul Stoodley2

1Biocomposites Ltd, Keele, United Kingdom. 2The Ohio State University, Columbus, Ohio, USA

Introduction: Antibiotic tolerant biofilms play an important role in the pathogenicity of chronic periprosthetic joint infection (PJI). Antibiotic-loaded calcium sulfate (ALCS*, Stimulan Rapid Cure) has shown promising results for eradication of these biofilms in-vitro. Antibiotic-loaded PMMA bone cement (AL-PMMA) and powdered antibiotic sprinkled in the surgical site (PAB) are additional strategies used to achieve high local concentrations of antibiotics. Here we describe an in-vitro flow reactor model, to better determine the predicted antibiotic concentration profile from these release strategies. 

Methods: A reactor flow system was used to pump solution simulating post-surgical drainage. The flow rate was adapted to align with clinical values. ALCS beads were loaded with vancomycin (VAN) at 1000mg and 240mg tobramycin (TOB) per 10cc/pack. PMMA spacers were unloaded or mixed with 2000mg VAN and TOB. PAB was performed using 1000mg of VAN directly added to the reactor. Effluent was collected, and VAN/TOB concentrations were semi-quantitatively assessed using zone of inhibition (ZOI) testing. 

Results: ZOI analysis showed an increased killing of S. aureus and P. aeruginosa and longer elution by ALCS compared with AL-PMMA and PAB. Additionally, ZOI testing showed increased killing with ALCS in combination with AL-PMMA than with AL-PMMA alone. With PAB, the VAN concentration dropped rapidly within 24-48 hours suggesting washout of the antibiotic. 

Discussion: Based on these in-vitro results, it is evident that ALCS beads loaded with VAN/TOB provide an extended release at above inhibitory concentrations for longer than a single bolus delivery and also provide an attenuated effect when used in combination with AL-PMMA.

Osteomyelitis in diabetic foot: radical approach vs conservative treatment

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Osteomyelitis in diabetic foot: radical approach vs conservative treatment

Sokol Hasho1, Eni Celo2

1Shefqet Ndroqi University Hospital, Tirana, Albania. 2Trauma University Hospital, Tirana, Albania

Aim: To evaluate the role of sequestrectomy as a better solution compared to long term conservative treatment in diabetic patients.

Method: We performed 52 consecutive sequestrectomies in 51 diabetic patients with bone involvement demonstrate by a positive probe to bone and a positive rx. For each patient the part of bone resected resulted with abnormal consistence and was collected in a sample. In our study there were 83% males and 14% females. Mean age was 68±8 years old. Mean HbA1c values 8.7±2.4%.

Results /Discussion: In our study 37 patients (72%) resulted with peripheral vascular   disease, while 15 patients (28%) had no arterial problems. In the hystological examination 48/52 patients (92%) resulted positive for osteomyelitis (presented acute inflammation, micro-abscesses, necrosis of trabecolae). In 4/52 patients (8%) resulted absence of osteomyelitis (presence of fibro productive process without infection). There were isolated a total of 54 strains. Among them 10 alert pathogens were identified (1 MRSA, 2 MRSCN, 1 Escherichia coli ESBL, 1 Klebsiella pneumoniae ESBL, 1 Pseudomonas aeruginosa ESBL, 2 VRE, 1 Acinetobacter lwofii MDR and 1 Acinetobacter calcoaceticus-baumanii complex MDR). Twenty-two patients presented complete healing of the wound with a mean healing time of 85 ± 38 days.  Antibiotic therapy was given orally for a mean duration of 21±10 days. No relapse of wounds or osteomyelitis was observed at the site of previous lesions in the follow up of 6 months. 

Conclusion: Limited removal of infected bone is associated with a high percentage of success in healing osteomyelitis with a very low relapse rate.

A comparison of enrichment culture media for the diagnosis of peri-prosthetic joint infection

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A comparison of enrichment culture media for the diagnosis of peri-prosthetic joint infection

Graham Harvey1,2, Karen Gibson1

1Department of Medical Microbiology, Shrewsbury and Telford Hospital NHS Trust, Shrewsbury. 2Robert Jones and Agnes Hunt OrthopaedicHospital, NHS Foundation Trust, Oswestry

Introduction: Various broth enrichment culture media have been advocated for the diagnosis of peri-prosthetic infections. We compared our in house method of enrichment in nutrient broth (NB) with a fastidious anerobic broth (FAB), Robertson’s cooked meat broth (RCM) and a continuous monitoring blood culture system (CMBCS) namely Becton Dickenson Bactec FX.

Methods: Revision arthroplasty samples were collected into vials of nutrient broth and disrupted with Ballotini glass beads. Samples were aliquoted into FAB, RCM and aerobic & anaerobic blood culture bottles. Broths were incubated at 35⁰C for a minimum of 5 days and sub-cultured onto blood and chocolate agar for 7 days. Blood culture samples were incubated for 5 days and sub-cultured only if they flagged positive. All isolates were identified by MALDi-ToF.

Results: 78 consecutive arthroplasty samples were included in this study. There was no growth in 53 samples and 7 were false positves.  18 samples were considered to be true positives, these comprised Staph epidermidis (10), Staph aureus (4), Enterococcus faecalis (2), Dermobacterium hominis (1), Candida albicans (1).

The sensitivity and specificity of the different media was as follows: nutrient agar 66.6% (41-87) and 91.7% (81-97); FAB 50.0% (26-74) and 96.6% (88-99); RCM 72.2% (46-90) and 98.3% (91-99); and CMBCS 88.2% (63-98) and 100% (94-100), respectively.

Conclusions: Our in house method using nutrient broth performed better than FAB and was comparable to RCM. The best results were obtained using the continuous monitoring blood culture system – this should be considered to be the method of choice.

Dig in your heels – a stubborn case of calcaneal osteomyelitis

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Dig in your heels – a stubborn case of calcaneal osteomyelitis

Robert Shaw, Danica Fernandes, Francis Collett-White, Matthew Scarborough, Bridget L Atkins, Constantinos Loizou

Bone Infection Unit, Oxford University Hospitals NHS Foundation Trust, Oxford

A 95-year-old retired engineer with type-2 diabetes presented with a two year history of worsening right heel pain. He had recently injured his Achilles tendon following a fall. On further questioning, he had joined the army in 1943 and received basic military training in Wales. During this time his feet were almost continuously wet and he had several bouts of athlete’s foot, with one episode resulting in inflammation up to his thigh. 

Examination revealed calcaneal tenderness along with tenderness over the distal Achilles tendon. There was no sinus or soft tissue inflammation. Radiographs showed a large lytic lesion (4x3cm) in the posterior aspect of the calcaneum. MRI demonstrated a simple intraosseous abscess with extensive bone marrow oedema. Histology from a fluoroscopic-guided biopsy showed a chronic inflammatory cell infiltrate, predominantly lymphocytes but with neutrophils in one area. Bacterial, fungal and mycobacterial cultures were negative. He was treated empirically with oral co-amoxiclav however developed progressive heel pain and a lateral discharging sinus.

Following MDT discussion, the patient underwent open sampling and partial calcanectomy. Bacterial, fungal and mycobacterial cultures and 16S-rDNA-PCR were negative. Intraoperative histopathology showed an inflammatory cell infiltrate with non-necrotising granulomata. 18S-rDNA-PCR detected Trichophyton interdigitale in two separate samples. After discussion with the fungal reference laboratory, he was started on oral itraconazole.

This case demonstrates the benefits of sending multiple samples for PCR in patients with culture-negative osteomyelitis. It reinforces the importance of the multidisciplinary approach, with unusual radiological and histopathological findings prompting further microbiological investigation.

Diagnosis: Trichophyton interdigitale abscess

Abstract without diagnosis

A 95-year-old retired engineer with type-2 diabetes presented with a two year history of worsening right heel pain. He had recently injured his Achilles tendon following a fall.

Examination revealed calcaneal tenderness along with tenderness and swelling over the distal Achilles tendon. There was no sinus or evidence of soft tissue inflammation. Radiographs showed a large lytic lesion (4x3cm) in the posterior aspect of the calcaneum. MRI demonstrated a simple intraosseous abscess with extensive bone marrow oedema extending to the posterior subtalar joint.

Histology from a fluoroscopic-guided biopsy showed a chronic inflammatory cell infiltrate, predominantly lymphocytes but with an accumulation of neutrophil polymorphs in one small area. Standard bacterial, fungal and mycobacterial cultures as well as 16S-rDNA-PCR were negative. He was treated empirically with six weeks of oral co-amoxiclav however towards the end of his course, he developed progressive heel pain and a lateral discharging sinus.

Following MDT discussion, the patient underwent open sampling and partial calcanectomy. Bacterial, fungal and mycobacterial cultures and 16S-rDNA-PCR were negative. Intraoperative histopathology showed an inflammatory cell infiltrate with non-necrotising granulomata including giant cells.  Mycobacterial and fungal stains were negative. He was started on oral ciprofloxacin and clindamycin before a final investigation revealed the diagnosis, necessitating a change of therapy.

Optimising antibiotic prophylaxis for hip and knee replacement; antibiotic susceptibility is not the whole story.

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Optimising antibiotic prophylaxis for hip and knee replacement; antibiotic susceptibility is not the whole story.

Ruth Shorrocks, Jason Webb, Maggie Alger, Elizabeth Darley

North Bristol NHS Trust, Bristol

Introduction: The optimal choice of antibiotic prophylaxis for Hip (THR) and knee (TKR) replacement is debated but with the recommendation that it is directed by local antibiotic resistance epidemiology.  Flucloxacillin 1g IV for 4 doses and gentamicin 5mg/kg stat is currently recommended at North Bristol NHS Trust (NBT). Cephalopsorins, used for prophylaxis in many centres, are avoided in the context of historical high rates of C difficle infection. Pathogens causing early surgical site infections (SSI) at NBT were compared to national data and their susceptibility to antibiotic prophylaxis analysed.

Methods: Cases of documented infection which were reported according to national SSI Surveillance Service criteria, for THR and TKR at NBT 2015-2018, were included.  Pathogens and susceptibility test results (EUCAST methodology) were confirmed with the microbiology IT system. National benchmarked data was used as a comparison.

Results: 44 NBT patients had early SSI in the 4 years. MSSA and Coagulase negative staphylococci were the predominant pathogens with similar proportions in THR locally and nationally but respectively caused 60% and 33% of NBT TKR infections compared to 40% and 23% nationally. There were no MRSA infections at NBT. 14% of NBT cases cultured ≥1 pathogen which was not susceptible to the prophylactic antibiotics.

Conclusions: Staphylococci remain the predominant infecting organisms.  At NBT, for 86% of infected patients organisms were reported as susceptible to prophylactic antibiotics given.  This suggests that selecting the optimal antibiotic prophylaxis may be more complex than simply applying local susceptibility results to inform antibiotic choice.

Case report: Managing a distal femoral physeal non-union secondary to neonatal osteomyelitis in an 8 year old

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Case report: Managing a distal femoral physeal non-union secondary to neonatal osteomyelitis in an 8 year old

Sanjeev Musuvathy Ravi1, Sachindra Nayak Kapadi2, Akshath Adapa3,

Bhalchandra Bhalerao3

1Wrightington Wigan and Leigh NHS Foundation trust, Wigan
2Wrightington Wigan and Leigh NHS Foundation Trust, Wigan
3Pennine Acute NHS Trust, Oldham

Treating distal femur non-union secondary to neonatal osteomyelitis can be a challenging task. It includes addressing the growth arrest at the physis by lengthening the femur along with bony union as well as achieving good range of motion at the knee joint. In this case report, our patient with right distal femoral physeal non-union had undergone acute docking of the femur and lengthening of the tibia over a knee-spanning Ilizarov ring fixator. 10 months later fixator was removed and length was achieved. Patient had stiffness of the knee in extension with further flexion of 0-20 degrees which persisted after intensive physiotherapy. Judet’s Quadriceps-plasty was performed. Post operatively, limb was immobilised in 120 degrees flexion. Post op day 5, flexion slab was removed, physiotherapy with CPM for 4 weeks was given, active knee flexion of 85 degrees was achieved. Judet’s quadriceps-plasty in cases of post limb lengthening using an Ilizarov fixator has not been well reported. We achieved reasonably good knee range of motion in our patient. This two-stage management is a good option to treat such cases.

Abstract without diagnosis

Treating distal femur non-union secondary to neonatal pathology can be a challenging task. It includes addressing the growth arrest at the physis by lengthening the femur along with bony union as well as achieving good range of motion at the knee joint. In this case report, our patient with right distal femoral physeal non-union had undergone acute docking of the femur and lengthening of the tibia over a knee-spanning Ilizarov ring fixator. 10 months later fixator was removed and length was achieved. Patient had stiffness of the knee in extension with further flexion of 0-20 degrees which persisted after intensive physiotherapy. Judet’s Quadriceps-plasty was performed. Post operatively, limb was immobilised in 120 degrees flexion. Post op day 5, flexion slab was removed, physiotherapy with CPM for 4 weeks was given, active knee flexion of 85 degrees was achieved. Judet’s quadriceps-plasty in cases of post limb lengthening using an Ilizarov fixator has not been well reported. We achieved reasonably good knee range of motion in our patient. This two-stage management is a good option to treat such cases.

A Hal’o a Case

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A Hal’o a Case

James Herdman, Joe Browning, Ruby Devi, T H Nick Wong

Buckinghamshire Healthcare NHS Trust, Aylesbury

A 68-year-old man initially presents with shortness of breath, lethargy and pancytopenia. He is subsequently diagnosed with acute monoblastic and monocytic leukaemia from a bone marrow aspirate and trephine biopsy and is given intensive chemotherapy (daunorubicin and cytarabine) with antifungal posaconazole prophylaxis. He was initiated on antibiotics to treat neutropenic sepsis, but respiratory symptoms persisted.

Chest radiograph demonstrated an opacity in the right upper lung lobe. CT imaging revealed an expanding mass in the right upper lobe with an ‘air-crescent’ sign. The patient was commenced on empirical liposomal amphotericin. Bronchio-alveolar lavage cultures were sent for 18S ribotyping and Rhizopus was detected. Ultrasound guided aspirates grew Aspergillus sp. Despite antifungal therapy, the mass continued to grow in size. A repeat CT scan demonstrated that the mass had invaded the second anterior rib causing a fracture. An additional antifungal isavuconaole was added.

The patient was transferred to a tertiary referral cardiothoracic centre where he underwent a lobectomy and rib resection. Histology confirmed a large fungal ball demonstrating fungal elements suggestive of Aspergillus species) which had invaded a 78mm section of rib as well as the right upper lobe. The patient remains on systemic antifungal therapy.

This case demonstrates that fungal infections can cause destructive osteomyelitis despite intensive medical therapy and can require complex multidisciplinary management.

Abstract without diagnosis

A 68-year-old man presents with shortness of breath and lethargy and is found to be pancytopenic. He is subsequently diagnosed with acute monoblastic and monocytic leukaemia and is given intensive chemotherapy (daunorubicin and cytarabine) with antifungal posaconazole prophylaxis. The patient became septic and was found to have a large mass in the right upper lobe of unknown aetiology.

CT scans demonstrated an expanding mass in the right upper lobe with an ‘air-crescent’ sign. He underwent bronchio-alveolar lavage and ultrasound guided aspirates. The patient was commenced on high dose treatment. Despite this, the mass continued to grow in size. A repeat CT scan demonstrated that the mass had invaded the second anterior rib and caused a fracture.

The patient was transferred to a tertiary referral cardiothoracic centre where he underwent a lobectomy and rib resection. Histology confirmed the diagnosis which has invaded a 78mm section of rib as well as the right upper lobe despite intensive medical therapy. The patient remains on treatment.

Aspergillus terreus: An unusual case of native vertebral osteomyelitis

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Aspergillus terreus: An unusual case of native vertebral osteomyelitis

Shadia Ahmed1, Richard Barton2, Jennifer Ratner2, Hugh McGann2

1York Hospital NHS Foundaton Trust, York, United Kingdom. 2Leeds Teaching Hospitals NHS Trust, Leeds

We present an unusual cause of native vertebral osteomyelitis in a 66 year old female patient with a history of T2DM. She presented with a 1 month history of back pain, fever and an elevated C-reactive protein (102 mg/L). Three weeks prior to admission she had returned from a two month trip to India and Pakistan. She denied any history of night sweats, cough or any TB contacts. MRI imaging revealed T8-9 vertebral osteomyelitis. Multiple blood cultures were sent and were negative. On Day 14 of her admission she underwent a CT-guided biopsy and samples were sent for bacterial and mycobacterial culture. Biopsy culture yielded no growth and a 16s PCR was negative. She was empirically treated with teicoplanin, and ciprofloxacin added later after she failed to improve.  Repeat MRI on day 20 showed disease progression. She then developed leukopenia secondary to the teicoplanin and so antibiotics were stopped on day 23. Three days later she had a mildly elevated β-D-glucan and a positive Aspergillus antibody. A second spinal biopsy was performed on day 31 and samples were sent for bacterial, mycobacterial and fungal culture. Empirical daptomycin and ciprofloxacin was commenced afterwards. Fungal cultures grew Aspergillus terreus and the patient was commenced on voriconazole.

This case highlights the benefits of performing a second spinal biopsy in cases where the initial biopsy is negative and patients fail to respond to empirical antibacterial therapy. Furthermore, a fungal aetiology should be considered irrespective of immune status, particularly in patients with diabetes.

Abstract without diagnosis

We present an unusual cause of native vertebral osteomyelitis in a 66 year old female patient with a history of T2DM. She presented with a 1 month history of back pain, fever and an elevated C-reactive protein (102 mg/L). Three weeks prior to admission she had returned from a two month trip to India and Pakistan. She denied any history of night sweats, cough or any TB contacts. MRI imaging revealed T8-9 vertebral osteomyelitis. Multiple blood cultures were sent and were negative. On Day 14 of her admission she underwent a CT-guided biopsy and samples were sent for bacterial and mycobacterial culture. Biopsy culture yielded no growth and a 16s PCR was negative. She was empirically treated with teicoplanin, and ciprofloxacin added later after she failed to improve.  Repeat MRI on day 20 showed disease progression. She then developed leukopenia secondary to the teicoplanin and so antibiotics were stopped on day 23. Three days later she had a mildly elevated β-D-glucan and a positive Aspergillus antibody. A second spinal biopsy was performed on day 31 and samples were sent for bacterial, mycobacterial and fungal culture. Empirical daptomycin and ciprofloxacin was commenced afterwards

Diagnosis was made based on the findings of the second biopsy culture.

This case highlights the benefits of performing a second spinal biopsy in cases where the initial biopsy is negative and patients fail to respond to empirical antibacterial therapy.

Tuberculous dactylitis (Spina Ventosa) of proximal phalanx in a 10-year-old girl– a case report

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Tuberculous dactylitis (Spina Ventosa) of proximal phalanx in a 10-year-old girl– a case report

Akshath Adapa1,2, Apoorv Kumar3, Sanjeev Musuvathy Ravi4, Sachindra Nayak Kapadi4

1Royal Oldham Hospital, Oldham, United Kingdom. 2. 3Manipal Hospitals, Bengaluru, India. 4Wrightington Wigan Leigh NHS foundation trust, Wrightington

Tubercular dactylitis, defined as Tubercular osteomyelitis of the short tubular bones of the hand and feet is an uncommon condition seen predominantly in children. The condition is characterised by cystic expansion of the bone due to filling up of the medullary canal with granulation tissue and pus and thinning of the overlying cortex, a condition radiologically termed as ‘spina ventosa’. We report a case of a 10-year-old girl who presented with a painful, slowly progressive swelling of two months’ duration in the index finger of right hand, without any associated history of trauma. The plain radiographs of the hand showed extensive destruction of the proximal phalanx of index finger with thinning of the overlying cortex. Magnetic Resonance Imaging (MRI) showed diffuse enlargement and focal cortical break in the proximal phalanx with thick organised fluid in the medullary canal with a small area of cortical breech. The finger was debrided and the digit stabilised by a K-wire which was removed at three weeks. Biopsy of the debrided material confirmed the clinical diagnosis of Tubercular osteomyelitis. The child was started on anti-tubercular drugs with aggressive mobilisation of the finger at three weeks. At one-year follow-up, the lesion had healed well with functional range of movements of the right index finger. 

Keywords: Tuberculosis dactylitis, spina ventosa, tuberculous granuloma.

Abstract without diagnosis

The condition is characterised by cystic expansion of the bone due to filling up of the medullary canal with granulation tissue and pus and thinning of the overlying cortex.

We report a case of a 10-year-old girl who presented with a painful, slowly progressive swelling of two months’ duration in the index finger of right hand, without any associated history of trauma. The plain radiographs of the hand showed extensive destruction of the proximal phalanx of index finger with thinning of the overlying cortex. Magnetic Resonance Imaging (MRI) showed diffuse enlargement and focal cortical break in the proximal phalanx with thick organised fluid in the medullary canal with a small area of cortical breech

An In-Vitro assessment of the bioactive profile of antifungal-loaded Calcium Sulfate beads

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An In-Vitro assessment of the bioactive profile of antifungal-loaded Calcium Sulfate beads

Mark Butcher1, Craig Delury2, Gordon Ramage1

1University of Glasgow, Glasgow, United Kingdom. 2Biocomposites, Keele

Introduction: The management of fungal osteomyelitis is challenging. The use of antibiotic loaded, fully absorbable calcium sulfate beads with antibiotics for local release has been well documented, but despite growing concerns about difficulty treating fungal infections, little data has been published.

Here we developed an in-vitro model where Calcium Sulfate (CS*) beads were mixed with amphotericin B, caspofungin, and fluconazole, to investigate their efficacy when introduced to clinically relevant fungi.

Methods: A panel of fungi were selected for preliminary Minimum Inhibitory Concentration (MIC) testingAfter establishing planktonic MICs, antifungal CS beads were introduced to fungal biofilms to assess biofilm formation and cell viability, through a combination of Crystal Violet and XTT assays. 

Inoculation of a hydrogel substrate, packed with antifungal CS beads, was used to assess diffusion through a semi-dry material, to mimic active infection in-vitro. This was assessed via colony counts, Q-PCR, light microscopy and electron microscopy.

Results: Established MICs remained consistent over 7-days, indicating controlled release of each antifungal. Amphotericin B and caspofungin reduced biomass and inhibited cell metabolism, whilst CS beads containing fluconazole displayed a fungistatic effect. SEM images confirm these findings

A similar trend followed in assessment of hydrogels, with a reduction in CFU when comparing CS beads loaded with caspofungin and amphotericin B.

Conclusion: Our results have shown that antifungal loaded CS beads produce a sustained antimicrobial effect over 7 days, which inhibits clinically relevant fungal species in-vitro.

*Stimulan Rapid Cure, Biocomposites.

Why toothpicks are bad for you?

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Why toothpicks are bad for you?

Saba Qaiser, Rajesh Sofat, Eleni Mavrogiorgou

East and North Hertfordshire NHS Trust, Stevenage

Background: Fusobacterium nucleatum is an anaerobic oral commensal and a periodontal pathogen associated with a wide spectrum of human diseases most notably in periodontal diseases, intrauterine infection, appendicitis, inflammatory bowel disease, and liver abscess. 

Bone and soft tissue infections with this organism although rare have been reported in literature.  We report an interesting case of F nucleatum infection in a previously healthy woman.

Materials/methods: We report a case of a 40 year old female, presenting to the Accident and Emergency department 2 months after treatment for left ankle cellulitis with medial malleolus pain, tenderness and fever. On initial presentation she had stepped into a used toothpick which was removed from the plantar aspect of the foot and received intravenous Teicoplanin. MRI ankle showed extensive hindfoot soft tissue inflammation with a small abscess and gas locules. She underwent aspiration of the ankle joint, incision of the posteromedial malleolus abscess and drainage with excision of the sinus tract edges. She was started on intravenous ertapenem via OPAT. 

Results: Tissue samples taken from the ankle were sent for microscopy and culture both of which were negative. Subsequently those samples were sent to the reference laboratory for 16s, Mycobacterium Tuberculosis and atypical mycobacteria PCRs.  Mycobacteria PCRs were negative but 16s PCR detected Fusobacterium nucleatum. Based on this result her treatment was changed to ceftriaxone and metronidazole and she had a full recovery after 6 weeks antibiotics.

Conclusions: This report highlights the importance of good history taking and keeping low threshold to suspect unusual bacterial infection.

Abstract without diagnosis

We report a case of a 40 year old female, presenting to the Accident and Emergency department 2 months after treatment for left ankle cellulitis with medial malleolus pain, tenderness and fever. On initial presentation she had stepped into a used toothpick which was removed from the plantar aspect of the foot and received intravenous Teicoplanin. MRI ankle showed extensive hindfoot soft tissue inflammation with a small abscess and gas locules. She underwent aspiration of the ankle joint, incision of the posteromedial malleolus abscess and drainage with excision of the sinus tract edges. She was started on intravenous ertapenem via OPAT. 16S PCR of the sample detected an unusual organism

Retrospective audit to establish the usefulness of 99M Tc SPECT-CT in the diagnosis of bone infection in a Regional Bone Infection Service/Limb reconstruction unit

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Retrospective audit to establish the usefulness of 99M Tc SPECT-CT in the diagnosis of bone infection in a Regional Bone Infection Service/Limb reconstruction unit

Dr S.Balamoody , Mr O. Uhiara,  Dr R Gadvi, Miss D Bose

Introduction:  Diagnosis of bone infection is clinically and radiologically challenging in patients who have had:

  • Previous orthopaedic trauma/polytrauma
  • Previous orthopaedic surgery
  • Metalwork of various forms.

MR imaging is not always suitable in these patients and interpretation difficult in the setting of trauma/surgical intervention.

Methods:  Total number of orthopaedic bone triple phase SPECT-CT cases from start of SPECT-CT service in 2011 to November 2014 excluding Neuro/spine and ENT cases.  Clinical and imaging data collected by an orthopaedic  SpR and Consultant Radiologist respectively who were blinded to each other’s data .  All SPECT-CT scans reviewed and scored for likelihood of infection. Those who had also undergone MRI imaging had further MR scoring for infection.  A similar clinical score was also obtained based on retrospective review of clinic letters. Operation notes, results of radiological bone biopsy, microbiology and histology results and clinical outcome were also used to form the clinical score where available. Sensitivity and specificity for SPECT-CT and MRI were obtained.

Results: 54 patients were analysed (57 SPECT-CTs), 44 of these had metalwork in situ. 19 patients had also undergone MRI. 4 patients had undergone image guided biopsy. 30 patients underwent surgery of which 20 of these had microbiology results available. Sensitivity for SPECT-CT (n=57) was 82% with specificity 94%. MRI (n=18) had a sensitivity of 44% and specificity of 50%.

Conclusion: Triple phase SPECT-CT has a very high specificity and high sensitivity for bone infection in these selected complex patients.

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