Abstract
INTRODUCTION
Interest in tissue-preserving or minimally invasive total hip arthroplasty (THA) is increasing with focus toward decreased hospital stay, enhanced rehabilitation, and quicker recovery for patients. Two tissue-preserving techniques, the anterior and superior approaches to THA, have excellent clinical results, but little is known about their relative impact on soft tissue. The purpose of this study was to evaluate the type and extent of tissue damage after THA with each approach, focusing on abductors, short external rotators, and the hip capsule.
METHODS
Total hip arthroplasty was performed on bilateral hips of eleven fresh-frozen cadavers (22 hips). They were randomized to anterior THA performed on one side and superior THA performed on the other, in the senior authors' standard technique. Two independent examiners graded the location and extent of tissue injury by performing postsurgical dissections. Muscle bellies, tendons, and capsular attachments were graded as intact, split, damaged (insignificant, minimal, moderate, or extensive damage), or detached based on direct visual inspection of each structure. Tissue injury was analyzed with either a chi-squared (≥5 qualifying structures) or Fisher's exact test (<5 qualifying structures). P values <0.05 were significant.
RESULTS
The abductor muscles or tendons were intact or insignificantly damaged in 63.6% of anterior approach specimens compared with 84.1% of the superior specimens (p= 0.03). Specifically, the gluteus minimus tendon had moderate or extensive damage in 63.6% of anterior specimens compared with none of the superior specimens (p <0.01). Short external rotators (SERs) group, defined as both the muscle and tendon of the piriformis, conjoint, obturator externus, and quadratus, were intact or insignificantly damaged in 63.6% of anterior approach specimens compared with 80.5% of the SER group of superior specimens (p = 0.02). The femoral attachments of the anterior, posterior, and superior capsules were extensively damaged or detached in 90.9%, 81.8%, and 100% of anterior approach specimens respectively compared with 0%, 9.1% and 9.1% of superior approach specimens respectively (all p <0.01).
CONCLUSION
In a cadaveric study examining superior and anterior approaches to THA, the superior approach demonstrated significantly less soft-tissue destruction than the anterior approach, specifically to the gluteus minimus tendon, short external rotators, and the hip capsule.
