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: Dislocation of a total hip arthroplasty (THA) is a common complication, the third leading reason for revision. Anterolateral approaches produce the lowest rate of dislocation but have many drawbacks. Few studies have examined the rate of dislocation of THA implanted via an anterior approach such as described by Hueter which appears to be more anatomic and less damaging. The purpose of this study was to determine the rate of dislocation of THA implanted via this approach and to search for associated risk factors.

Material and methods: A prospective study included 1764 THA in 1374 patients, 891 females and 483 males, implanted between 1997 and 2003. Age ranged from 22 to 84 years (69±10.8). The right side was involved in 996 cases and the left in 768. Two senior surgeons performed the operations using the anterior approach described by Hueter. A cemented implant with a metal-backed polyethylene cup was used. The group of patients who presented at least one dislocation was compared with the group of patients free of dislocation. The effect of clinical, radiolgical, and prosthetic factors was studied: age, gender, body mass index, etioloy, intraoperative blood loss, head diameter, cup inclination and anteversion. Pearson’s chi-square test and Student’s t test were applied with a 5% level of significance.

Results: The rate of dislocation was 1.5% (27 patients). The rate of dislocation after discharge to home was 0.8%. All dislocations occurred early, from postoperative day 1 to 56, mean 13.8 days (SD 15.25). One patient underwent revision for reduction. Two underwent revision for recurrent instability (0.11%). Significant risk factors were male gender (p< 0.001), young age (p< 0.001), elevated body mass index (p< 0.001), osteonecrosis (p< 0.001), significant intraoperative blood loss (p< 0.001), head diameter 22.22 vs 28 (p< 0.001).

Discussion: The Hueter approach significantly reduces the risk of dislocation. This might be explained by the less invasive nature of the approach since it does not require any muscle section.

Conclusion: The risk of dislocation after implantation of a THA via the anterior Hueter approach is one of the lowest reported in the literature (0.8% after discharge to home). Subjects at risk are five years younger, overweight males operated on for osteonecrosis with significant intraoperative blood loss and a 22.22 diameter femoral head.