title: Surgical treatment of femoroacetabular impingement: evaluation of the effect of the size of the resection.
abstract: BACKGROUND
  In patients with symptomatic hip impingement, surgical resection of the femoral head-neck junction may improve the range of motion and relieve pain. A risk of this procedure is fracture. We evaluated the amount of resection of the anterolateral aspect of the femoral head-neck junction that can be done safely.
  
  
  METHODS
  Cadaveric proximal femoral specimens (fifteen matched pairs) were divided into three groups: 10%, 30%, or 50% of the diameter of one femoral neck was removed, and the contralateral femoral neck was left intact to serve as the control. A compressive load was applied directly to the femoral head. Peak load, stiffness, and energy to fracture were compared among the groups.
  
  
  RESULTS
  The energy to fracture differed significantly (p = 0.0015) among the 10%, 30%, and 50% resection groups. The peak load after the 50% resection was significantly less (p = 0.0025) than that after the 10% or 30% resection. With the numbers available, there was no significant difference in peak load between the 10% and 30% resections.
  
  
  CONCLUSIONS
  Resection of up to 30% of the anterolateral quadrant of the head-neck junction did not significantly alter the load-bearing capacity of the proximal part of the femur. However, a 30% resection significantly decreased the amount of energy required to produce a fracture. Thirty percent should be considered to be the greatest feasible amount of resection because of the change in the pattern of the femoral head-neck response to axial loads that we observed.
authors.affiliation: Department of Orthopedic Surgery and Orthopedic Biomechanics Laboratory, Mayo Clinic, Rochester, Minnesota 55905, USA.
authors.forename: Rodrigo M
authors.initials: RM
authors.lastname: Mardones
authors.forename: Carlos
authors.initials: C
authors.lastname: Gonzalez
authors.forename: Qingshan
authors.initials: Q
authors.lastname: Chen
authors.forename: Mark
authors.initials: M
authors.lastname: Zobitz
authors.forename: Kenton R
authors.initials: KR
authors.lastname: Kaufman
authors.forename: Robert T
authors.initials: RT
authors.lastname: Trousdale
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001178:Arthroplasty / Q000009:adverse effects / Q000379:methods*; D002102:Cadaver; D019245:Compressive Strength / Q000502:physiology; D005260:Female; D005265:Femoral Neck Fractures / Q000209:etiology / Q000517:prevention & control*; D005270:Femur Head / Q000601:surgery*; D005272:Femur Neck / Q000503:physiopathology* / Q000601:surgery*; D006801:Humans; D007592:Joint Diseases / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016059:Range of Motion, Articular / Q000502:physiology; D016474:Weight-Bearing / Q000502:physiology