Aim

Periprosthetic joint infection (PJI) is nowadays the most important problem leading to failure in primary and revision total knee (TKA) and total hip arthroplasty (THA), therefore accurate diagnosis of PJI is necessary. We evaluated a commercial multiplex PCR system1 for diagnosis of PJI in joint aspiration fluids prior to surgery.

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.

Purpose of the study: Plurimicrobial infections account for 4 to37% of all infections of total hip arthroplasties (THA). According to data in the literature, they are the source of failure, contraindicating one-phase replacement procedures. The purpose of our study was to evaluate the results of our management practices in this group of patients and also to identify factors of risk associated with multimicrobial infection.

Material and methods: A prospective study included 116 patients with an infected THA from November 2002 to December 2006. Sixteen patients (13.8%), mean age 68±12.7 years had a plurimicrobial infection defined by having at last two interoperative bacteriological samples positive for two or more germs. Surgical treatment consisted in a single-phase replacement in seven cases, a two-phase replacement in seven, resection of the head and neck in one, and wash-out resection in one. Mean duration of the antibiotic therapy ws 91±6 days, including 46±14 days intravenously. Anaerobic germs were isolated more commonly in plurimicrobial infections than monomicrobial infections (50% versus 11%). Patients were assessed with prospectively collected data. Mean follow-up was 34±13 months, with none lost to follow-up. The main outcome was apparent cure rate of the initial infection at minimum two years follow-up, defined by the absence of clinical, biological and radiographic signs of infection, and absence of death attributable to infection or its treatment. If infection was suspected, a hip puncture or intraoperative samples confirmed the relapse (same germs) or reinfection (different germs).

Results: The cure rate was 100% for plurimicrobial infections and 97% for monomicrobial infections. There were however four reinfections in the monomicrobial group. In this series, the risk factor statistically associated with plurimicrobial infections was the presence of a fistula with an odds ratio of 5.4.

Discussion: A larger number of patients would probably enable identification of other risk factors associated with plurimicrobial infections.

Conclusion: The cure rate of plurimicrobial infections was higher than reported in the literature but for a small group of patients. The presence of a fistula was strongly associated with these plurimicrobial infections.

Purpose of the study: The purpose of this work was to analyse the results of infection in patients with joint prostheses implanted after septic arthritis, distinguishing evolving versus cured arthritis.

Material and methods: This was a retrospective series of 70 cases of septic arthritis (in 69 patients) including 7 patients with mycobacterial infections and 63 patients with ordinary germ infections. For the seven mycro-bacterial infections (five Mycobacterium tuberculosis and two Mycobacterium xenopi), the arthroplasty was implanted on evolving arthritis and in two on arthritis considered cured. For the 63 cases of common germs (70% staphylococcal infections), the septic arthritis was considered evolving in 36 and cured in 27. For half of the cases, the arthritis was blood-borne and localised in the knee. For cases considered evolving, the arthroplasty was generally a two-phase procedure (32/36 cases). Adapted antibiotics were associated for 93 days on average (45–180). For arthritis considered cured, the arthroplasty was implanted on average 53 months (range 6–700) after the infectious episode, generally in a one-phase procedure (22/27). Adapted antibiotics were associated for 80 days on average in seven patients because of positive intraoperative samples. One patient was lost to follow-up before two years and all others were reviewed with at least two years follow-up (mean 5 years, range 2–13 years).

Results: For the seven cases of mycobacterial arthritis, one patient was lost to follow-up, six had no signs of infection at mean 7 years follow-up. For the other cases, 89% of patients who had a prosthesis for evolving arthritis were considered as cured, 6% relapsed before 18 months and 6% presented a new infection with a different germ. For arthroplasty after assumed cured arthritis, 81% of patients were considered cured, 15% relapsed before 18 months and 4% presented a new infection with another germ.

Discussion: Arthroplasty is the treatment of choice for septic evolving septic arthritis, enabling cure in more than 80%, irrespective of the causal germ, and whether cure of the infection was apparently achieved or not.

Introduction: The goal of the study was to evaluate our treatment protocols for peri-prosthetic infection after total hip replacement.

Méthode: A prospective study carried out between February 2003 and February 2005, included 100 patients treated for peri-prosthetic infection after total hip replacement. Debridement and prosthesis retention was performed in case of duration of symptoms of less than 14 days (11 cases), otherwise a one-stage (42 cases) or a two-stages (41 cases) prosthesis removal and re-implantation were carried out. A two-stage procedure was decided in case of important bone loss or undetermined germ. If general health state did not allow a re-implantation, an isolated prosthesis removal was performed (6 cases). Post-operatively, patients received intravenous antibiotics (6 weeks), then oral antibiotics (6 weeks). The mean follow-up was 2.2 years with no lost to follow-up. The main evaluation criteria was the rate of infection eradication with 2 years minimal follow -up. In case of a suspected new infection, a hip aspiration was performed to determine whether it was a non-eradication (same germ) or a new re-infection (other germ) which was not considered as a failure.

Results: Infection eradication rate was 95% and 100% for the one-stage surgical procedure. 5 failures were recorded (2 deaths and 3 non-eradications). However, 3 patients were re-infected with different germs. The rate of non-infected patiens at the last follow-up was 92%.

Conclusion: Our protocols were validated with a high success rate of 95%. Peri-prosthetic infection of the hip is severe even if well treated with a mortality rate of 2%.

Purpose: We report results of management of infected total knee arthroplasty (TKA). Our aim was to analyse the different therapeutic options and identify factors predictive of cure.

Material and methods: This retrospective multicentric analysis included a consecutive series of 179 cases of infected TKA. Revision TKA was performed for 77 knees in two operative times, 30 in one operative time. Synovecetomy was performed for 26 knees, arthrodesis for 36 and amputation for nine. Minimum follow-up was two years. For each case, we assessed cure of infection and functional outcome. Non-parametric statistical tests were used to compare outcome.

Results: Mean follow-up was 41.2 months. There was a 17% death rate during the first two years after management of infected TKA. Cure was achieved in two-thirds of the revised cases (in one or two operative times) and in 54% of the synovectomy cases. Arthrodesis yielded cure in 50%. Staphylococci was identified in 65%. The functional outcomes of revised prostheses (two times) was less satisfactory if the anterior tibial tubercle was removed, if the extensor system was involved, or if a flap cover was necessary (p< 0.05). There was no significant difference in functional outcome for one-time and two-time operations. Cure was achieved in 95% of the synovectomies performed before 16 days. Relapse occurred in 95% of those performed after 56 days. Arthrodesis performed in patients with major bone loss failed. Among the arthrodesis failures, 50% were related to mechanical failure and the other 50% to recurrent infection.

Discussion: We discuss these results and indications for different treatments of infected total knee arthroplasty. For each therapeutic option, we analysed factors allowing hope for cure and good functional outcome.

Conclusion: The objective of treatment of an infected TKA is to achieve cure and maintain satisfactory function, often a difficult goal to reach. Major mutilating surgery can be avoided by early adapted care.