The Effect of Surgical Approach on Strength and Function after Total Hip Arthroplasty.

Background: Although total hip arthroplasty (THA) has become standard procedure to manag the symptoms of end-stage osteoarthritis (OA), there are multiple surgical approaches to acceE the hip joint. To date, there is limited information on the effect of surgical approach on muscle strength and performance-based measures of functional ability after THA.

Questions/purposes: The purpose of this study was to compare the effect of posterior or anterolateral surgical approaches on strength and function after THA. We hypothesized that individuals who underwent a posterior approach would have greater strength and performance-based measures of function than individuals who underwent an anterolateral approach one year after surgery. We also hypothesized that there would be no difference in pain or self-reported outcomes at follow-up.

Methods: 63 subjects were tested two to four weeks prior to THA and then three months and 12 months after THA. Subjects were divided into a posterior approach and lateral approac groups. Patients completed functional testing, strength measures, as well as self-reported questionnaires at each time point. Repeated-measures analysis of variance (ANOVA) tests were performed to test the change between the pre-operative and one year time point. Descriptive data were reported for all three time points.

Results: There was a significant interaction effect for hip abduction strength (p=0.025) and the lateral group was significantly weaker at one year (p=0.018). No other variable demonstrated a significant interaction effect; however, all other variables with the exception of hip abductor strength (p=0.883) and pain on the non-operated side (p=0.527) demonstrated a significant main effect of time (p≤0.01) in which there was significant improvement at 1 year.

Conclusion: The lateral surgical approaches result in weaker hip abduction one year after THA; however significant and clinically meaningful improvements in functional ability were seen for most subiects. regardless of surgical approach.