title: Preoperative gluteus medius muscle atrophy as a predictor of walking ability after total hip arthroplasty.
abstract: OBJECTIVE
  To elucidate the relation between certain preoperative physical parameters and walking with a limp after total hip arthroplasty (THA) and determine whether it is possible to predict the walking ability of patients 6 months after THA.
  
  
  METHODS
  The subjects of this study comprised 74 female patients who had undergone unilateral THA. Before surgery, the hip abductor and knee extensor strengths were measured, the cross-sectional areas (CSAs) of the gluteus medius and rectus abdominis muscles were measured, and the Timed Up and Go test was conducted. The patients were then divided into two groups according to gait observation results 6 months postoperatively: walking without a limp (n=37) and walking with a limp (n=37).
  
  
  RESULTS
  The discriminating criteria between the two groups were age (61 years), CSA of the gluteus medius muscle (2000 mm2), and CSA of the rectus abdominis muscle (340 mm2). In the multiple logistic regression analysis, the gluteus medius muscle was the only significant predictor of limping after THA (β=1.64, R2=0.19, p<0.01).
  
  
  CONCLUSIONS
  The results of the present study suggest that preoperative atrophy of the gluteus medius is an useful indicator for predicting walking with a limp 6 months postoperatively.
authors.affiliation: Rehabilitation Unit, Kyoto University Hospital.
authors.forename: Manabu
authors.initials: M
authors.lastname: Nankaku
authors.affiliation: Human Health Sciences, Graduate School of Medicine, Kyoto University.
authors.forename: Tadao
authors.initials: T
authors.lastname: Tsuboyama
authors.affiliation: Human Health Sciences, Graduate School of Medicine, Kyoto University.
authors.forename: Tomoki
authors.initials: T
authors.lastname: Aoyama
authors.affiliation: Department of Orthopedic Surgery, Faculty of Medicine, Kyoto University.
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Kuroda
authors.affiliation: Rehabilitation Unit, Kyoto University Hospital.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Ikeguchi
authors.affiliation: Department of Orthopedic Surgery, Faculty of Medicine, Kyoto University.
authors.forename: Shuichi
authors.initials: S
authors.lastname: Matsuda
keywords: Gluteus medius muscle; Predictors; Total hip arthroplasty