The anterior-based muscle-sparing approach to the hip: the "other" anterior approach to the hip

The purpose of this study was to evaluate safety, efficacy, and learning curves of anterior-based muscle-sparing total hip arthroplasty (ABMS-THA) in the supine position. Furthermore, early functional outcome was evaluated and compared to direct anterior approach (DAA) by measuring surface electromyography (sEMG).

PurposeThe purpose of this study was to evaluate safety, efficacy, and learning curves of anterior-based muscle-sparing total hip arthroplasty (ABMS-THA) in the supine position. Furthermore, early functional outcome was evaluated and compared to direct anterior approach (DAA) by measuring surface electromyography (sEMG).MethodsWe present a prospective cohort study of 343 hips. The safety and learning curve were assessed by recording operative time and peri-operative adverse events. For assessment of efficacy, functional and radiological outcomes were evaluated. A selected group of 32 patients have been studied by sEMG and compared to a matched group of 32 patients who received a THA using DAA approach.ResultsThere was one dislocation (0.3%); two (0.6%) patients had an intra-operative fractures of the greater trochanter; two patients (0.6%) experienced a self-limited femoral nerve palsy. Physical therapy milestones for hospital discharge were reached on an average of 1.7days. sEMG showed that ABMS and DAA have a similar muscle recruitment pattern and functional recovery after THA. One patient was revised for infection, 16 were lost, and 326 hips were available with a median follow-up of 42months (range 24-60). The mean Harris Hip Score (HSS) increased from 44.3 to 91.9. Ninety-six percent of the hips had a leg length discrepancy (LLD) <5mm. There were no radiological signs of mechanical loosening or osteolysis.ConclusionsThe ABMS approach in the supine position is clinically effective and safe; special advantages include a very low dislocation rate and a great control of LLD.