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Dr. Marc Philippon Study on Femoroacetabular Impingement Recognized as Top Ten Most Cited Articles of 2008-2011 by Arthroscopy Journal

According to Arthroscopy, the journal for arthroscopic and related surgery, Dr. Marc Philippon’s orthopaedic research study, “Relationship Between Offset Angla Alpha and Hip Chondral Injury in Femoroacetabular Impingement”, was one of the top ten most cited articles for 2008-2011.  Dr. Marc Philippon is a Managing Partner at The SteadmanClinic in Vail, Colorado and Director of Hip Research at Steadman PhilipponResearch Institute.

The full orthopedic research study “Relationship Between Offset Angla Alpha and Hip Chondral Injury in Femoroacetabular Impingement,” along with images and references, can be found on Arthroscopy’s website along with the abstract below that details the purpose of the study, methods used, and the results that were concluded:


The purpose of this study was to examine the relationship between the size of cam lesions and the presence of cartilage damage, labral damage, or changes in range of motion in the hips with signs and symptoms of femoroacetabular impingement (FAI).


Cross-table lateral radiographs were available for 102 consecutive patients presenting with signs and symptoms of FAI. Radiographs with excessive external rotation, dysplasia, severe arthritis, avascular necrosis, or Legg-Calvé-Perthes syndrome were excluded, leaving 82 patients available for analysis.  This study included 47 men and 35 women with an average age of 25 years (12 to 55). Offset angle alpha was measured from the films with a digital goniometer. Patients subsequently underwent hip arthroscopy and thesurgical findings and hip range of motion were prospectively recorded.


Higher offset angle alpha was associated with the presence of acetabular rim chondral defects (P = .044) and full-thickness delamination of the acetabular cartilage (P = .034). Patients with detachment of the base of the labrum had a higher offset angle alpha (P = .016). Higher offset angle alpha was related to male sex (P = .001) and decreased range of motion (P < .05), but not to age.


Cam-type FAI, as measured by an increased offset angle alpha, was correlated with increased chondral damage, labral injury, and decreased range of motion.

Relationship Between Offset Angla Alpha and Hip Chondral Injury in Femoroacetabular Impingement is on Pubmed.

Dr. Philippon

  • American Academy of Orthopaedic Surgeons
  • American Orthopaedic Society for Sports Medicine
  • International Society for Hip Arthroscopy
  • Arthroscopy Association of North America