PROSPECTIVE STUDY OF DISLOCATION AFTER TOTAL HIP ARTHROPLASTY VIA THE ANTERIOR HUETER APPROACH

Abstract

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.