Aims

Cutibacterium acnes (C. acnes; previously known as Propionibacterium acnes or P. acnes) periprosthetic hip and knee infections are under-reported. While culture contamination with C. acnes occurs, true infections are important to recognize and treat. We sought to describe the demographics and treatment outcomes of patients with C. acnes periprosthetic joint infections (PJIs) of the hip and knee.

The number of shoulder arthroplasty procedures performed in the United States continues to rise. Currently, the number of procedures performed per year ranges from 55,000–80,000 and is expected to increase more than 300% in the coming years. Periprosthetic joint infection (PJI) is one of the most serious complications associated with arthroplasty surgery, leading to poor outcomes, increased cost, and technically difficult revision surgery. The incidence of infection following primary shoulder arthroplasty has been reported between 0.7% and 4%, representing 2.9–4.6% of all complications. Prosthetic shoulder joint infections are unlike prosthetic joint infections of the hip and knee. Shoulder PJIs are primarily indolent in nature and difficult to diagnose using traditional methods that have been shown to be accurate for periprosthetic infections of the hip and knee. The majority of infected revision shoulder arthroplasties are associated with growth of Propionibacterium acnes (P. Acnes). This slow-growing, anaerobic organism requires longer than normal incubation times for culture (7–21 days), and typically demonstrates a subtle, non-specific clinical presentation that can make the presence of infection difficult to identify. In the reported literature, P. Acnes accounts for about 70% of cases with positive cultures associated with revision for treatment of a painful shoulder arthroplasty and due to the bacteria's slow growing nature and virulence profile, the rate of infection following shoulder arthroplasty may often be underestimated. A more recent and promising tool for evaluation of periprosthetic infection has been analysis of synovial fluid. Synovial fluid biomarkers have been identified as part of the innate response to pathogens, and include pro-inflammatory cytokines and anti-microbial peptides, and marker levels have shown promise for improved diagnostic efficacy in hip and knee PJI. Currently, no highly predictive clinical test for diagnosis of PJI in the shoulder exists, however, several of these synovial biomarkers have recently been analyzed for their diagnostic capacity in the setting of periprosthetic shoulder infection. Synovial fluid cytokine analysis shows the potential to improve diagnosis of infection in revision shoulder arthroplasty. This information can help to guide decision-making in the management of PJI of the shoulder, including the decision to perform a single- vs. two-stage revision surgery, and the need for post-operative antibiotics following an unexpected positive culture result after revision surgery. However, there are still challenges to broader use of these synovial biomarkers. Synovial α-defensin (Synovsure, CD Diagnostic) is the only marker currently available as a commercial test, and no point-of-care test is currently available for any of the biomarkers to allow for intraoperative decision-making. While a preoperative synovial aspirate is possible to send for α-defensin analysis currently, with results back in approximately 24 hours, dry fluid aspirations are frequent in the shoulder because of the predominance of indolent pathogens and may limit utility of the test. In summary, indolent infection associated with P. acnes is a common cause for the painful total shoulder arthroplasty. Pre-operative diagnosis of infection is difficult as a result of the poor diagnostic accuracy of traditional methods of testing. Synovial biomarker testing may ultimately improve our ability to more accurately diagnosis and treat prosthetic shoulder joint infections

Little information is available regarding the demographic characteristics and outcomes of patients with periprosthetic joint infection (PJI) resulting from anaerobic organisms, especially in the knee joint. We performed a retrospective cohort analysis of all cases of knee PJI that were treated at our institution during the period from 2005 through 2012. Anaerobes were involved in 11 (13%) of 86 first-time episodes of knee PJI, and peptostreptococcus was the most commonly isolated pathogen (10 [91%] of the 11 episodes). The average age of patients was 70 years (range, 62 to 79) and women were more than men (7 vs. 4) to develop anaerobic PJI. Of the 11 episodes of anaerobic PJI, 8 (73%) were treated with 2-stage revision arthroplasty for chronic latent infection, and 3 (27%) with parenteral antibiotics for positive intraoperative culture. Those treating with 2-stage revision arthroplasty had average 21 months prosthetic age (range, 2 to 41), and 10 weeks interim period between stages (range, 7 to 14). The overall successful rate for treating anaerobic knee PJI was 90%, and 88% for chronic latent infection. naerobic PJI represents a substantial proportion of all occurrences of knee PJI. Treating with resection of the prosthesis and subsequent reimplantation is associated with a favorable outcome for chronic latent infection

Peri-prosthetic joint infection (PJI) can be both a diagnostic and therapeutic challenge in shoulder arthroplasty, due to the indolent nature of the common infecting organisms. Proprionobacterium acnes (P. acnes) is the most common pathogen cultured in revision shoulder arthroplasty. It is a slow growing, anaerobic organism – requires longer incubation period (7–21 days). Coagulase-negative Staphylococcus species (CNSS) is also a common organism responsible for PJI. Established diagnostic tests for hip and knee PJI are often negative in the shoulder despite post-operative growth of intra-operative cultures. Pre-operative synovial aspiration often low volume due to indolent pathogens and successful aspiration is often reported to be 50% or less with Dilisio et al, JBJS 2014: reporting 16.7% sensitivity, 100% specificity. Variable culture length for P. acnes culture protocols are reported from 7–28 days with most groups recommending 14 days. From our research, we demonstrated time to culture growth was significantly shorter in probable true positive culture group (median, 5 vs. 9 days, p=0.002). Frozen section analysis may help intra-operative decision-making (one- vs. two-stage reimplantation) yet the reported sensitivity and specificity in shoulder arthroplasty is far less than in hip and knee arthroplasty. Synovial fluid biomarkers have been identified as part of the innate response to pathogens include pro-inflammatory cytokines and antimicrobial peptides. In a series of prospective studies of revision shoulder arthroplasty, synovial fluid analysis reported by Frangiamore et al, JBJS 2015: IL-6, Frangiamore et al, JSES 2015: α-defensin (Synovasure. TM. ), Frangiamore et al, AAOS 2015: Broader cytokine analysis it was demonstrated that these markers are much more predictive of infection than synovial fluid cultures, frozen section or serum markers

Aims

We aimed to describe the epidemiological, biological, and bacteriological characteristics of osteoarticular infections (OAIs) caused by Kingella kingae.

Aims

Diabetes mellitus is the most common co-morbidity associated with necrotising fasciitis. This study aims to compare the clinical presentation, investigations, Laboratory Risk Indicator for Necrotising Fasciitis (LRINEC) score, microbiology and outcome of management of this condition in diabetic and non-diabetic patients.

Non-tuberculous mycobacterial (NTM) infection of the musculoskeletal tissue is a rare disease. An early and accurate diagnosis is often difficult because of the indolent clinical course and difficulty of isolating pathogens. Our goal was to determine the clinical features of musculoskeletal NTM infection and to present the treatment outcomes. A total of 29 patients (nine females, 20 males between 34 and 85 years old, mean age 61.7 years; 34 to 85) with NTM infection of the musculoskeletal system between 1998 to 2011 were identified and their treatment retrospectively analysed. Microbiological studies demonstrated NTM in 29 patients: the isolates were Mycobacterium intracellulare in six patients, M. fortuitum in three, M. abscessus in two and M. marinum in one. In the remaining patients we failed to identify the species. The involved sites were the hand/wrist in nine patients the knee in five patients, spine in four patients, foot in two patients, elbow in two patients, shoulder in one, ankle in two patients, leg in three patients and multiple in one patient. The mean interval between the appearance of symptoms and diagnosis was 20.8 months (1.5 to 180). All patients underwent surgical treatment and antimicrobial medication according to our protocol for chronic musculoskeletal infection: 20 patients had NTM-specific medication and nine had conventional antimicrobial therapy. At the final follow-up 22 patients were cured, three failed to respond to treatment and four were lost to follow-up. Identifying these diseases due the initial non-specific presentation can be difficult. Treatment consists of surgical intervention and adequate antimicrobial therapy, which can result in satisfactory outcomes.

Cite this article: Bone Joint J 2014;96-B:1561–5.

Necrotising fasciitis is a rare but severe infection of soft-tissue associated with rapid progression, systemic toxicity and high mortality. Monomicrobial necrotising fasciitis caused by Pseudomonas aeruginosa is exceptionally uncommon with only 12 cases reported in the literature. We describe a fatal case with an atypical presentation in a patient following spinal decompression for a metastasis from prostate cancer.

We report our experience using a biodegradable calcium sulphate antibiotic carrier containing tobramycin in the surgical management of patients with chronic osteomyelitis. The patients were reviewed to determine the rate of recurrent infection, the filling of bony defects, and any problems with wound healing. A total of 193 patients (195 cases) with a mean age of 46.1 years (16.1 to 82.0) underwent surgery. According to the Cierny–Mader classification of osteomyelitis there were 12 type I, 1 type II, 144 type III and 38 type IV cases. The mean follow-up was 3.7 years (1.3 to 7.1) with recurrent infection occurring in 18 cases (9.2%) at a mean of 10.3 months post-operatively (1 to 25.0). After further treatment the infection resolved in 191 cases (97.9%). Prolonged wound ooze (longer than two weeks post-operatively) occurred in 30 cases (15.4%) in which there were no recurrent infection. Radiographic assessment at final follow-up showed no filling of the defect with bone in 67 (36.6%), partial filling in 108 (59.0%) and complete filling in eight (4.4%). A fracture occurred in nine (4.6%) of the treated osteomyelitic segments at a mean of 1.9 years (0.4 to 4.9) after operation.

We conclude that Osteoset T is helpful in the management of patients with chronic osteomyelitis, but the filling of the defect in bone is variable. Prolonged wound ooze is usually self-limiting and not associated with recurrent infection.

Cite this article: Bone Joint J 2014; 96-B:829–36