Radiological variables associated with progression of femoroacetabular impingement of the hip: A systematic review

Abstract Objectives Femoroacetabular impingement is gaining increased recognition as a cause of hip dysfunction. Of great concern is its potential association with labral tears and osteoarthritis. This systematic review examines the evidence regarding radiographic variables associated with the progression of femoroacetabular impingement. Design Systematic review. Methods Articles were selected following a comprehensive search of PubMed, CINAHL, SportDiscus, Embase, and Medline databases from database inception through October 2012. Inclusion criteria involved (1) estimates of the association between prognostic variables and progression of femoroacetabular impingement, (2) prospective or retrospective design, (3) patients diagnosed with femoroacetabular impingement based on established criteria, (4) the outcome of interest was radiologic and/or clinical progression of femoroacetabular impingement, and (5) access to the full text. Two independent reviewers assessed the methodological quality of each study and the association between prognostic variables and femoroacetabular impingement progression. Results Thirteen articles met the inclusion criteria; nine were considered to be of high quality. Moderate evidence of progression of femoroacetabular impingement to labral pathology was associated with increased alpha angle. Moderate evidence for their lack of association with progression of FAI was associated with alpha angle with respect to development of osteoarthritis, acetabular index, center edge angle, coxa profunda, coxa vara, and pistol grip deformity. Conclusions There is moderate evidence that increased alpha angle at baseline is associated with progression of femoroacetabular impingement to labral tear. Moderate evidence suggests a lack of association between other radiographic variables and progression of femoroacetabular impingement.