title: How accurately can the acetabular rim be trimmed in hip arthroscopy for pincer-type femoral acetabular impingement: a cadaveric investigation.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the precision of central hip arthroscopy in the assessment and treatment of pincer-type femoroacetabular impingement (FAI) avoiding the posterolateral portal, with its close proximity to the main arterial blood supply of the femoral head, the medial circumflex femoral artery.
  
  
  METHODS
  Seven human cadaveric hips underwent arthroscopic trimming of the acetabular labrum and rim along a preoperatively defined 105 degrees arc of resection for treatment of a presumed pincer-type lesion. After the arthroscopic procedure, all specimens were dissected and measured for evaluation of the location, quantity, and quality of the area undergoing resection.
  
  
  RESULTS
  The difference between the actual and planned arc of resection was 18.7 degrees +/- 4.7 degrees (range, 2 degrees to 34 degrees). This was mainly because of a lack of accuracy in the presumed posterior starting point (PSP), with a mean deviation of 19 degrees +/- 3.4 degrees (range, 10 degrees to 36 degrees). Correlation analysis showed that variance in the arc of resection was mainly dependent on the PSP (r = 0.739, P = .058).
  
  
  CONCLUSIONS
  Central hip arthroscopy is a feasible option in treating anterosuperior pincer-type FAI by use of the anterior and anterolateral portals only. This cadaveric study showed that there is a significant risk of underestimating the actual arc of resection compared with the planned arc of resection for posterosuperior pincer-type lesions because of the modest accuracy in determining the PSP of the resection.
  
  
  CONCLUSIONS
  Accurate preoperative planning and arthroscopic identification of anatomic landmarks at the acetabular side are crucial for the definition of the appropriate starting and ending points in the treatment of pincer-type FAI. Whereas anterosuperior pincer-type lesions can be addressed very precisely with our technique, the actual resection of posterosuperior lesions averaged 19 degrees less than the planned resection, which may have clinical implications.
authors.affiliation: Department of Orthopedic Surgery, Balgrist Hospital, University of Zurich, Zurich, Switzerland. m.zumstein@bbox.ch
authors.forename: Matthias
authors.initials: M
authors.lastname: Zumstein
authors.forename: Frederik
authors.initials: F
authors.lastname: Hahn
authors.forename: Atul
authors.initials: A
authors.lastname: Sukthankar
authors.forename: Patrick S
authors.initials: PS
authors.lastname: Sussmann
authors.forename: Claudio
authors.initials: C
authors.lastname: Dora
mesh_terms: D000077:Acetabulum / Q000601:surgery*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001182:Arthroscopy / Q000379:methods*; D002102:Cadaver; D003238:Connective Tissue / Q000601:surgery; D005260:Female; D005263:Femoral Artery; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects