title: Effect of soft-tissue impingement on range of motion during posterior approach Total Hip Arthroplasty: an in vivo measurement study.
abstract: OBJECTIVE
  While implant impingement and bony impingement have been recognized as causes of poor outcomes in total hip arthroplasty (THA), reports of soft-tissue impingement are rare. To clarify the issue, the effect of anterior capsule resection on hip range of motion (ROM) was quantitatively measured in vivo during posterior approach THA using a CT-based hip navigation system.
  
  
  METHODS
  For 47 patients (51 hips), hip ROM was measured intraoperatively before and after resection of the anterior hip capsule, and the difference was compared.
  
  
  RESULTS
  Resection of the anterior hip capsule brought about an average 6° increase of ROM in the direction of flexion with internal rotation and did not markedly change ROM in other directions.
  
  
  CONCLUSIONS
  During THA through a posterior approach, soft-tissue impingement by the anterior hip capsule can occur. Clinically, we expect that resection of the anterior hip capsule can reduce the risk of posterior instability without increasing the risk of anterior instability.
authors.affiliation: a Center of Arthroplasty, Kyowakai Hospital , Suita-city , Osaka , Japan.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Nakamura
authors.affiliation: a Center of Arthroplasty, Kyowakai Hospital , Suita-city , Osaka , Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Maeda
authors.affiliation: a Center of Arthroplasty, Kyowakai Hospital , Suita-city , Osaka , Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Hamawaki
authors.affiliation: b Department of Orthopedic Surgery , Osaka University Medical School , Suita-city , Osaka , Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Sakai
authors.affiliation: b Department of Orthopedic Surgery , Osaka University Medical School , Suita-city , Osaka , Japan.
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Sugano
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000379:methods*; D015331:Cohort Studies; D065187:Controlled Before-After Studies; D005260:Female; D057925:Femoracetabular Impingement / Q000209:etiology / Q000517:prevention & control*; D006801:Humans; D017746:Joint Capsule / Q000601:surgery*; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D011183:Postoperative Complications / Q000209:etiology / Q000517:prevention & control*; D016059:Range of Motion, Articular / Q000502:physiology*; D014057:Tomography, X-Ray Computed
keywords: Total hip replacement; cup positioning; navigation; surgical skill evaluation