Pelvic Inclination Angle and Hip Abductor Muscle Strength after Total Hip Arthroplasty

Abstract

[Purpose] We investigated whether pelvic inclination angle (PIA) influences hip abductor strength and gait ability after total hip arthoplasty (THA). Additionally, we assessed whether preoperative PIA is useful as a predictor of hip abductor strength and ambulation ability after THA. [Subjects] Thirty-six women patients with unilateral THA (age: 67.9 ± 10.0; body weight: 56.8 ± 9.1 kg; height: 150.2±8.3 cm; BMI: 25.1±3.6 kg/m²)participated in this study. [Methods] We measured pre- and postoperative PIA, hip abductor strength, hip pain (visual analog scale: VAS), and subjects performed the timed up and go (TUG) test, and the 10-m gait speed test. [Results] PIA showed onetime decrease in pelvic tilt at 1 week postoperatively, and thereafter generally exhibited a posterior change after THA. The patients with postoperative posterior PIA showed late recovery of abductor muscle strength and inferior TUG test results compared to patients with anterior or neutral PIA. The hip abductor strength and TUG test results of patients with preoperative posterior PIA were significantly lower than those of patients with preoperative anterior or neutral PIA. [Conclusions] PIA affected hip abductor strength and TUG test resulting, which were associated with a decrease in hip pain, and preoperative PIA may be useful for predict short-term hip abductor strength and ambulation ability after THA.