Similar Improvement in Gait Parameters Following Direct Anterior and Posterior Approach Total Hip Arthroplasty

Introduction: Direct anterior approach (DAA) total hip arthroplasty (THA) has been reported to be a muscle sparing approach. The purpose of this study was to compare gait patterns over time between patients undergoing THA via DAA and posterior approach (PA). Methods: 22 patients with unilateral primary hip osteoarthritis were prospectively enrolled and gait analysis was performed prior to, at 6 months and 1 year following THA via DAA and PA. All PA THA9s were performed by a single surgeon from January 2008 to February 2009; all DAA THA9s were performed by the same surgeon at the same institution from January 2010 to May 2011 with similar design of uncemented acetabular, femoral components and bearing surfaces. Reflective markers were placed on the lower extremity and motion data collected using six infrared cameras (Qtrac, Qualysis). Ground reaction forces were recorded with a multicomponent force plate (Kistler). A repeated-measures ANOVA was used to compare changes in gait parameters over time. Harris Hip Score was used to quantify pain and function. Results: There were 11 patients in both groups with similar age, sex and BMI distribution. Postoperatively, both groups demonstrated improvement in flexion/extension range of motion (ROM) (p = 0.006), peak flexion (p = 0.05) and extension moments (p = 0.004) with no differences between groups. Internal/external ROM improved significantly and was higher in DAA group as compared to PA group (p = 0.05). Gait velocity and single-leg stance time improved significantly in PA group (p = 0.001), but they were similar between groups postoperatively. Pain and function scores were also similar. Conclusions: THA performed via DAA and PA offer similar improvement in gait parameters at 6 months and 1 year follow-up with the exception of internal/external ROM. This might be indicative of altered hip mechanics related to release and repair of external rotators during PA THA.