title: Vascular safe zones in hip arthroscopy.
abstract: BACKGROUND
  Hip arthroscopy is an evolving surgical technique being performed in greater numbers because of advances in skill, improved technology, and increased demand. Identifying vascular safe zones using anatomic and intracapsular landmarks provides a valuable intraoperative guide to reduce the risk of damage to the femoral head blood supply during femoral neck osteoplasty and psoas tendon release.
  
  
  OBJECTIVE
  This series is presented to identify vascular safe zones for use in hip arthroscopy.
  
  
  METHODS
  Case series; Level of evidence, 4.
  
  
  METHODS
  The authors analyzed 76 consecutive contrast-enhanced magnetic resonance scans obtained from patients with diagnosed femoral acetabular impingement. High-resolution 3-dimensional images were reconstructed to visualize the vasculature. The medial femoral circumflex artery (MFCA) course was traced from the anterior thigh to the femoral head. Specific attention was paid to its proximity to the psoas tendon at the site of release and the retinacular vessel course in relation to the femoral neck using a clock-face orientation.
  
  
  RESULTS
  The MFCA was found inserting on the posterior superior femoral neck from the 10:30 to 12-o'clock position on the femoral neck shaft, just posterior to the lateral synovial fold, and progressed on the femoral neck via an average of 4 retinacular vessels (range, 2-6). Ninety-seven percent of vessels were posterior to the 12-o'clock position. The MFCA passes posteriorly a mean distance of 50% ± 8% between the lesser trochanter and inferior femoral head/acetabular junction, located a mean 15 ± 0.37 mm medial to the medial cortex of the femoral neck. The MFCA was within the middle third zone in 100% of the measurements.
  
  
  CONCLUSIONS
  The authors defined the following 2 safe zones: the femoral neck osteoplasty safe zone is on the anterior half of the femoral neck; the psoas tendon release safe zone is astride the middle third of the medial hip capsule (bordered by the lesser trochanter and inferior femoral head/acetabular junction).
authors.affiliation: Harvard Combined Orthopedic Surgery Residency Program, Massachusetts General Hospital, Boston, Massachusetts, USA. fmccormick@partners.org
authors.forename: Frank
authors.initials: F
authors.lastname: McCormick
authors.forename: Conor P
authors.initials: CP
authors.lastname: Kleweno
authors.forename: Young Jo
authors.initials: YJ
authors.lastname: Kim
authors.forename: Scott D
authors.initials: SD
authors.lastname: Martin
mesh_terms: D000293:Adolescent; D000328:Adult; D001182:Arthroscopy / Q000379:methods*; D001808:Blood Vessels / Q000033:anatomy & histology*; D005260:Female; D057925:Femoracetabular Impingement / Q000601:surgery; D005270:Femur Head / Q000098:blood supply; D006615:Hip / Q000033:anatomy & histology* / Q000601:surgery*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D019300:Medical Errors / Q000517:prevention & control*; D008875:Middle Aged; D055815:Young Adult