title: Elevation of the femur in THA through a direct anterior approach: cadaver and clinical studies.
abstract: BACKGROUND
  The direct anterior approach in THA is an intermuscular approach that requires no muscle detachment. However, it is difficult to elevate the proximal femur for access to the femoral canal.
  
  
  OBJECTIVE
  We asked (1) which part of the capsule should be released to allow effective elevation of the proximal femur; (2) whether the release of the internal obturator tendon allows elevation; and (3) whether hip hyperextension reduces the ability to elevate the femur.
  
  
  METHODS
  We conducted a cadaver study and a clinical study. In the first study, the elevation of the proximal femur was measured in 6 hips in 3 cadavers after excision of the anterior capsule, after the release of the superior capsule or the posterior capsule, after the release of the superior and posterior capsule, and after the release of the internal obturator tendon under traction of 70 N. Each hip was positioned at 0°, 15°, and 25° hyperextension. In the second study of 39 patients, the posterior capsule was released after the superior capsule in the first 13 hips, and the superior capsule was released after the posterior capsule in the next 26 hips. The elevation achieved for each hip was measured as in the cadaver study.
  
  
  RESULTS
  In our cadaver study, hip elevation increased after superior capsule release but not after release of the internal obturator tendon. After superior capsule release, the ability to elevate the femur was not diminished by hip hyperextension. In our clinical study, elevation increased after superior capsule release.
  
  
  CONCLUSIONS
  Superior capsule release was most effective of all releases for elevating the proximal femur in the direct anterior approach.
authors.affiliation: Department of Orthopaedic Surgery, Saiseikai Nakatsu Hospital, 2-10-39, Shibata, Kita-ku, Osaka, 530-0012, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Matsuura
authors.forename: Hirotsugu
authors.initials: H
authors.lastname: Ohashi
authors.forename: Yusaku
authors.initials: Y
authors.lastname: Okamoto
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Inori
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Okajima
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D002102:Cadaver; D005260:Female; D005269:Femur / Q000601:surgery*; D006621:Hip Joint / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D007564:Japan; D017746:Joint Capsule / Q000601:surgery; D008297:Male; D016059:Range of Motion, Articular; D013710:Tendons / Q000601:surgery; D016896:Treatment Outcome
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