LIGAMENT PRESERVING TOTAL HIP ARTHROPLASTY PREVENTS DIFFERENT LEG LENGTH AND FEMORAL OFFSET

OBJECTIVES: The leg length (LL) and femoral offset (FO) discrepancy following total hip arthroplasty (THA) are important factors for postoperative outcomes and restoring native hip biomechanics is essential for THA. Hip capsular ligament contributes to joint stability; however, there are few studies about the influence of ligament preservation on LLD and FO following THA. METHODS: We conducted a retrospective study involving 60 patients who underwent primary THA using a short stem through the anterolateral approach between June 2016 and August 2018. From August 2017, we preserved the vertical band of iliofemoral ligament and the pubofemoral ligament in THA, and the compared pre- and postoperative radiographic LLD and FO difference between the ligament preservation (n = 30) and ligament excision (n = 30) groups. RESULTS: Postoperative LLD was significantly smaller in the ligament preservation than in the ligament excision group. The ratio of excessive LLD and FO difference was lower in the ligament preservation group than the ligament excision one. CONCLUSION: The preservation of the hip capsular ligament suppressed the increased LLD and FO difference. Level of Evidence II; Prognostic Study - Investigation of the Effect of a Patient Characteristic on the Outcome of a Disease .