The Effects of the Surgical Approach on the Postoperative Gait Mechanics Following Total Hip Arthroplasty

Introduction: Minimally invasive total hip arthroplasty (THA) is advertised to allow improved and faster rehabilitation due to reduced soft-tissue damage compared to THA performed with a standard transmuscular approach. The aim of this prospective Level II study was to analyze gait function after THA using 3 different approaches and 2 different types of prostheses. Patients and Methods: Ten patients underwent THA through a minimally invasive anterior (n=5) or antero-lateral (n=5) approach using conventional ceramic-onceramic prostheses. In comparison, 8 metal-on-metal resurfacing arthroplasties were implanted through a posterior approach. An instrumented three-dimensional gait analysis was performed to evaluate gait function preoperatively, 6-weeks and 6-months postoperatively after implantation. The Harris Hip Score (HHS) and the Western Ontario and McMaster Universities Arthritis Index (WOMAC) were used to evaluate the functional clinical outcome. Results: The preand postoperative gait analyses showed constantly all but one no differences between the three groups for gait parameters. Only the step length was significantly longer in case of anterior and posterior approach compared to the antero-lateral approach (p=0,025). The scoring systems (HHS, WOMAC) resulted in nearly identical preand postoperative scores with excellent functional outcome in all groups. Conclusions: The current study indicates that there are no functional differences at 6-months follow-up for THAs performed through different approaches. The only difference at gait analysis performed 6-months following hip arthroplasty showed to be longer stride length for the anterior and posterior approach in comparison to the THA group performed through an antero-lateral approach. Central Friesenbichler et al. (2015) Email: Ann Orthop Rheumatol 3(4): 1056 (2015) 2/6 discrepancy, higher range of motion, and easier revision [4]. Minimally invasive approaches to the hip are known to reduce soft tissue damages and therefore, they are supposed to provide earlier mobilization and rehabilitation of the patient in the early postoperative phase. Several studies reported functional outcome following THA using gait analysis as one of the most objective tools for postoperative data assessment [1,4-20]. Most of these studies demonstrated slower walking speed and smaller step length following THA. Further, reduced muscle strength (e.g. gluteal muscles) and reduced range of motion in the hip and knee joint, especially in case of extension in the late stance phase, are supposed to cause impairments of gait adaptation. Additionally, due to a more invasive surgical technique in case of RHA in comparison to conventional or minimally invasive THA, it is expected that the range of motion as well as the muscle strength would be more affected in the early postoperative phase. The purpose of this prospective, Level II study was to investigate preand postoperative changes in gait symmetry in patients receiving a THA through a minimally invasive anterior or anterolateral approach or RHA through a posterior approach. We hypothesized functional differences present between patients who had undergone THA with the minimally invasive approaches (anterior and antero-lateral) and patients who had undergone RHA with a posterior approach. MATERIALS AND METHODS