title: Muscular recovery of hip flexors and extensors after two-incision total hip arthroplasty.
abstract: BACKGROUND
  The influence of two-incision total hip arthroplasty on muscular function has not been reported. We hypothesized that recovery could be different for the hip flexors and extensors because an intermuscular interval was used in the flexors but a trans-muscular approach was used for the extensors.
  
  
  METHODS
  Two-incision total hip arthroplasties were performed in 10 patients (8 men and 2 women) with a mean age of 47.2 years (range, 27 to 63 years). Muscle torques were measured prospectively in the 10 patients using a cybex dynamometer preoperatively, 6 weeks postoperatively, and at the latest follow-up.
  
  
  RESULTS
  It was found that muscle torque improved from 0.51 (preoperative) to 0.68 Ft-Lbs/Lbs 6 weeks postoperatively. (p=0.007) However, this improvement was contributed by the flexors but not the extensors. In contrast to the flexors, the torques of the extensors significantly decreased to 86%, 78%, and 63% at the angular velocity of 60 degrees/min, 90 degrees/min, and 180 degrees/min, respectively, 6 weeks postoperatively. At the most recent follow-up (average 40 +/- 2 months), differences could not be found in either the flexors or the extensors compared with the unaffected side.
  
  
  CONCLUSIONS
  The causes for the delayed recovery of hip extensor muscles could be related to surgical techniques that traverse the muscle during femoral canal preparation and stem implantation. This study suggests that the two-incision technique can be further refined in view of the muscular function.
authors.affiliation: Department of Physical Medicine and Rehabilitation, Chang Gung Memorial Hospital, Taipei, Chang Gung University College of Medicine, Taoyuan, Taiwan.
authors.forename: Shih-Wei
authors.initials: SW
authors.lastname: Chou
authors.forename: Steve W N
authors.initials: SW
authors.lastname: Ueng
authors.forename: Mel S
authors.initials: MS
authors.lastname: Lee
mesh_terms: D000328:Adult; D019644:Arthroplasty, Replacement, Hip; D005260:Female; D005271:Femur Head Necrosis / Q000503:physiopathology* / Q000601:surgery; D006615:Hip / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D015207:Osteoarthritis, Hip / Q000503:physiopathology* / Q000601:surgery; D019415:Torque