Aims. This study aimed to evaluate calprotectin in synovial fluid for diagnosing chronic prosthetic joint infection (PJI) . Methods. A total of 63 patients who were suspected of PJI were enrolled. The synovial fluid calprotectin was tested by an enzyme-linked immunosorbent assay (ELISA). Laboratory test data, such as ESR, CRP, synovial fluid white blood cells (SF-WBCs), and synovial fluid polymorphonuclear cells (SF-PMNs), were documented. Chi-squared tests were used to compare the sensitivity and specificity of calprotectin and laboratory tests. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve was calculated to determine diagnostic efficacy. Results. The median calprotectin level was 776 μg/ml (interquartile range (IQR) 536.5 to 1132) in the PJI group and 54.5 μg/ml (IQR, 38.75 to 78.25) in the aseptic failure (AF) group (p < 0.05). Using a threshold of 173 ug/ml, the sensitivity was 95.2%, with a 97.6% specificity, and the AUC was 0.993. The sensitivity of calprotectin of the antibiotic-treated PJI group was 100% versus 90.9% of the non-antibiotic-treated PJI group. Although 47.6% (ten cases) of the patients in the PJI group received antibiotics before aspiration, the diagnostic efficacy of calprotectin was not affected. The sensitivity and specificity of ESR, CRP, SF-WBCs, and SF-PMNs ranged from 76.2% to 90.5% and 64.3% to 85.7%, respectively. Conclusion. Calprotectin in synovial fluid has great diagnostic efficacy for PJI diagnosisand outperformed ESR, CRP, SF-WBCs, and SF-PMNs. Cite this article: Bone Joint Res 2020;9(8):450–456

Diagnosis of chronic prosthetic joint infection (PJI) is often challenging. Painful prosthesis is frequently due to an infection but to diagnose it is somethimes difficult. All recent guidelines stress the central role of joint punction in diagnosis of PJI if the infection is not demonstrated. However which test on synovial fluid must be carried out is not so clearly defined. Total white blood cell count and differential leukocite count are usually considered useful in diagnosis but cut offs reported by different studies are quite different. Moreover this test needs a relatively large amount of fluid and blood contamination of it largely affects the result. What's more the synovial fluid WBC count may be unreliable in the setting of a metal-on-metal bearing or corrosion reaction. Routine cultures should be maintained between 5 and 14 days, their sensitivity appears low in chronic infection even if witholding antimicrobial therapy before the collection of the fluid can increase the likelihood of recovery an organism. Synovial leukocyte esterase can be performed as a rapid office or intraoperative point of care test using urinalysis strips. It is cheap and easy to perform, but the presence of blood in the sample can affect the result and it needs centrifugation. Recently a new test has been proposed to detect alfa-defensine in synovial fluid. It shows a high sensitivity and an exellent specificity. We performed 25 joint punctions on 25 patients with suspected PJI (enrollment is going on). Synovial fluid collected was tested for: leukocite esterase, WBC count and differential, colture in blood colture bottle for anerobe and aerobes (BacT/ALERT Biomerieux, inc) and detection of alfa-defensine level (Synovasure – Zimmer). In patients who underwent surgery at least 5 samples of periprotesic tissue were collected for microbiologic analysis and the removed implant was sonicated according with the methodic. Furthermore samples for frozen section were sent and a histologic examination was made according to the Moriewitz – Kerr classification. The MSIS criteria was utilized to classify the case as infected or not

Aim. Diagnosing or excluding a chronic prosthetic joint infection (PJI) prior to revision surgery can be a clinical challenge. To enhance accuracy of diagnosis, several biomarkers were introduced in recent years, but most are either expensive or not available as a rapid test. We compared the diagnostic accuracy of leucocyte esterase (€0.20 per sample), calprotectin (€20 per sample) and alpha defensin (€200 per sample). Method. We prospectively evaluated PJI patients with chronic pain with or without prosthetic loosening between 2017 and 2018. Synovial fluid was collected prior to revision surgery. Leucocyte esterase was measured using a reagent strip (2+ considered as positive), and calprotectin and alpha defensin were measured using a lateral flow immunoassay. Intraoperative cultures (5 periprosthetic tissue samples, synovial fluid and sonication fluid) incubated for 9 days, were used as gold standard. At least two positive cultures of low-grade microorganisms with the same antibiogram were required to diagnose PJI. Results. A total of 19 patients were included (knee =11, hip =8). None of the patients were treated with antibiotics prior to revision surgery. A PJI was diagnosed in 8 patients (42.1%). The diagnostic accuracy of leucocyte esterase vs. calprotectin vs. alpha defensin was as follows; sensitivity 50.0% vs. 87.5% vs. 87.5%, specificity 81.8% vs. 90.9% vs. 100%, positive predictive value 60.0% vs. 87.5% vs. 100% and negative predictive value 75.0% vs. 90.9% vs. 91.6%, respectively. Both calprotectin and alpha defensin were false negative in one PJI caused by Cutibacterium acnes. The other two C. acnes PJIs were correctly diagnosed with both tests. Conclusions. Calprotectin is as accurate as alpha defensin in excluding a chronic PJI at 10% of the costs. Future studies with a large number of patients are necessary to analyze its diagnostic accuracy in very low-grade infections, in particularly caused by C. acnes

Aim

Pre-operative distinction between prosthetic joint infections (PJI) and non-infectious causes of joint failure is particularly challenging, especially in chronic situations. Guidelines propose different algorithms using numerous preoperative tests. We evaluated place of serology.

Exchange of infected implant using antibiotic-impregnated cement is the treatment of choice in prosthetic joint infection (PJI). We presented our experience using one or two-stage exchange with uncemented implants.

From January 2000 to June 2006 patients with a PJI that were treated with one or two-stage exchange with uncemented implants, were prospectively followed up. The treatment protocol consisted of radical excision of devitalized tissue and of maintaining a high serum antibiotic concentration during surgery followed by systemic antibiotic administration according to the microbiology results. Only patients with ≥6 months of follow-up were included. Good evolution was considered when symptoms and signs of infection disappeared and the C-Reactive Protein was normal.

Forty-two patients were included in the study, of whom 25 were male. The mean age was 70 years. The most common symptom was pain (100%) and radiological signs of prosthesis loosening were present in 36 cases (85.7%). Histology was positive in 32 patients (76.2%). Coagulase-negative staphylococci was the most common microorganism (23 cases) followed by S. aureus (5 cases). One-stage exchange was performed in 18 patients, and the long stem component was always uncemented. In one case an acute infection after the arthroplasty obligated to perform an open debridément without implant removal. After a mean follow-up of 31 months (range: 6–84) all patients had a good evolution. In 24 cases a 2-stage exchange with a joint spacer with gentamycin (Spacer-G) was performed. In all cases the definitive arthroplasty was performed using an uncemented long stem. Good evolution was documented in all but one case with persistent infection due to S. aureus after a mean follow-up of 19 months (range: 12–48).

Our results suggest that uncemented arthroplasty following a protocol based on radical debridément and systemic antibiotic therapy during and after surgery is a useful approach in PJI.

Aim

This study aims to describe our department experience with single stage revision (SSR) for chronic prosthetic-joint infection (PJI) after total hip arthroplasty (THA) between 2005 and 2014 and to analyze success rates and morbidity results of patients submitted to SSR for infected THA according to pathogen.

Aims. To explore the effect of different types of articulating antibiotic-loaded cement spacers in two-stage revision for chronic hip prosthetic joint infection (PJI). Methods. A retrospective cohort study was performed involving 36 chronic PJI patients treated with different types of articulating antibiotic-loaded cement spacers between January 2014 and December 2017. The incidence of complications and the therapeutic effects of different types of antibiotic-loaded articulating cement spacers were compared. Results. A total of 36 patients with chronic hip PJI were included. Of these, 13 patients were treated with spacers with Kirschner wires as an endoskeleton (group I), ten patients were treated with spacers with a cemented femoral prosthesis as an endoskeleton (group II), and 13 patients were treated with cemented femoral prostheses combined with polyethylene sockets as a spacer (group III). All patients were followed for 12 to 60 months, with a mean follow-up period of 26.44 months (SEM 14.09). Infection was controlled in 34 patients (94.44%), and there were no significant differences in the eradication rate among the three groups (p = 0.705), but the risk of complications related to the spacer in group III was significantly lower than that in groups I and II (p = 0.006). Conclusion. Articulating antibiotic-loaded cement spacers is effective in the treatment of chronic hip PJI, but we must pay attention to the occurrence of spacer fracture and dislocation, which can lead to poor joint function. The risk of spacer-related mechanical complications is low, and better joint function can be achieved when using cemented femoral prostheses combined with polyethylene sockets as spacers. Cite this article: Bone Joint Res 2020;9(8):484–492

Background: Chronic prosthetic joint infection is a cause of patient morbidity and can be challenging to treat. Surgeons performing revision arthroplasty of the hip and knee are confronted with a growing number of patients with extensive loss of bone stock. The use of a modular endoprosthesis is a possible method of treatment in such patients. Aim: The purpose of this study was to assess the functional outcomes and the success of a single and two stage revision procedure in eradicating chronic prosthetic joint infection using a femoral endoprosthesis. Methods: A prospective database was reviewed of 20 patients who underwent a proximal, total or distal femoral endoprosthetic replacement after chronic prosthetic infection. Radiographs performed at the time of latest follow up were evaluated for signs of loosening, osteomyelitis and implant failure. The functional status was assessed using the Short Form (SF)-36 health survey score, Toronto extremity salvage score (TESS) and the Enneking score. Results: Thirteen patients underwent a single stage revision procedure and seven had been treated with a staged revision. At the latest follow up none of the 13 patients treated with a single stage procedure had evidence of ongoing infection. Of the seven patients who had a staged revision, 3 patients had evidence of ongoing infection. The mean pre operative Enneking score for the entire group was 17.1 points and this improved to 47.5 points post operatively (p< 0.0002). The mean pre operative TESS score for the entire group was 42% and this improved to 59% post operatively (p< 0.005). There was also a statistically significant improvement in all of the components of the SF-36 score. Conclusion: We believe that the use of a modular endo-prosthesis in the treatment of chronic prosthetic joint infection is a successful and viable option in eradicating infection, preserving the limb and providing a good functional result

Aim. The treatment of a chronic prosthetic joint infection (PJI) is a combination of the bacteria's identification, a «carcinological» surgery and an appropriate antibiotherapy. In case of gram positive cocci infection, rifampicin is often used. The aim of this study is to determine which factors are responsible for the development of resistance to rifampicine. Method. All patients had a total hip (THA) or knee (TKA) arthroplasty with a chronic infection. They were treated with a two-time surgery. All of them received a bi-antibiotic treatment. In case of gram positive cocci infection, and according to the susceptibility test, they received rifampicin. The 221 patients were operated from July 1997 to November 2013 in 3 university centers (one Belgian and two French) and were retrospectively analysed. The demographical, clinical and bacterial data as well as the antibiotic treatment were collected. The healing was defined as the absence of recurrence during the 2 years following surgery. Results. Among the 221 patients (from 22 to 91 years old, median age: 67), 133 (60%) had a THA infection. 22% of the peroperative samples collected during the first time surgery were sterile. 64% were mono-microbial and 14% were poly-microbial. For 69% of them, gentamycin-impregnated spacers were used and for 26% of them vancomycin and gentamycin-impregnated spacers were used. The median delay for the second time surgery was 52 days (15 to 221 days). The healing was higher for the patients treated by an antibiotic combination with rifampicin than the others (86 vs 72%; p=0.02). In the same way, the healing rate was higher in patients where the delay between the two surgeries was less than one month (91 vs 77%; p=0.09). There were more recurrence in TKA than in THA (30% vs 13%, p=0.006). 12 % of the patients showed a persistence of the germ or the emergence of a new microorganism with a comparable antibiogram. A resistance to rifampicin during the second surgery appears in 9 % of cases. Conclusions. Theses study results suggest the benefit of the use of rifampicin for the treatment of gram positive cocci prosthetic joint infections treated by a two time surgery. In all cases, intravenous antibiotic therapy was maintained until the wound was closed to decrease the emergence of resistance

Aim. Treatment of chronic prosthetic joint infection (PJI) combines exchange arthroplasty and effective antibiotic therapy. Staphylococci are the most frequent microorganism isolated in PJIs, with resistance to methicillin found in 15–50% of the cases. Data from randomized trials on treatment of methicillin-resistant staphylococci are lacking and the choice of antibiotic(s) and recommendations vary according to authors. To date, combination therapy including vancomycin is the treatment of choice. Minocycline, a cyclin antibiotic, is naturally effective against methicillin-resistant staphylococci. We use this antibiotic since many years in combination with vancomycin for the treatment of multi-drug resistant staphylococcal bone and joint infections. The aim of this study is to analyze the outcome of patients treated with combination antibiotic therapy including minocycline for the treatment of chronic methicillin-resistant staphylococcal PJI. Method. We conducted a cohort study between 2004 and 2014 in our referral center for bone and joint infections. Data were extracted from the prospective database. All the patients receiving an initial combination therapy including at least 4 weeks of minocycline, given orally, and another IV antibiotic, usually high-dose continuous IV vancomycin, for chronic MR staphylococcal PJI and who underwent one or two stage exchange arthroplasty, were included. They were followed prospectively for at least 2 years. Results. We included 42 patients: 26 patients (62%) had one-stage, 16 patients (38%) had two stage exchange arthroplasty. Median duration of IV and total antibiotic therapy was 42 [40–44] days and 84 [84–88] days, respectively. 41 patients (98%) received vancomycin as associated initial therapy. Thirty-six patients received 100mgx3 per day of minocycline. Six received >300mg per day because of low serum concentrations. Median follow-up was 48 months (IQR 27–58). Survival rate without infection was 84,5% at 2 years, 70.2% at 6 years. Four patients reported adverse events due to minocycline: one had grade 4 thrombopenia leading to minocycline withdrawal, two had grade 2 liver toxicity. One patient had grade 1 nauseas. Two patients with MR Staphylococcus epidermidis knee arthroplasty experienced relapse. Three patients with hip arthroplasty infection developed a new infection within 2 year due to MSSA, Pseudomonas aeruginosa, and plurimicrobial for the last one. Three further patients developed a new infection 3 (n=2) and 4 years later. They were all acute haematogenous infections. Conclusions. Our data support the use of minocycline combination therapy with high-dose IV vancomycin for the treatment of chronic PJI due to methicillin-resistant Staphylococci