Prevalence of Femoral and Acetabular Version Abnormalities in Patients With Symptomatic Hip Disease: A Controlled Study of 538 Hips.

BACKGROUND Variations in femoral and acetabular version are becoming increasingly recognized as contributing factors to the development of hip pain in patients with femoroacetabular impingement (FAI) and hip dysplasia. It is still unknown what the true prevalence of these rotational abnormalities is in this patient population. PURPOSE To determine (1) the prevalence of femoral version abnormalities in symptomatic hips with FAI and hip dysplasia, (2) the prevalence of combined abnormalities of femoral and acetabular version in these patients, and (3) which specific hip morphologies are associated with abnormalities of femoral version. STUDY DESIGN Cross-sectional study; Level of evidence, 3. METHODS A total of 462 symptomatic patients (538 hips) were included who had hip pain attributed to FAI or hip dysplasia and who presented to our tertiary referral center for hip preservation surgery between 2011 and 2015. We retrospectively examined femoral and acetabular version among 11 subgroups with predefined hip morphologies and compared findings with a control group. The allocation to each subgroup was based on morphologic reference values for femoral head coverage, lateral center edge angle, alpha angle, and neck-shaft angle calculated on plain radiographs. RESULTS Of the 538 hips included, 52% were found to have abnormal femoral version; severe abnormalities were found in 17%. Severely decreased femoral version (35°), in 12%. The most frequent abnormal combination was increased femoral version combined with normal acetabular version (22%). We found significantly lower mean femoral version for the cam-type FAI group (15°) and significantly higher mean femoral version for the Perthes hips (32°; ie, Legg-Calvé-Perthes disease) as compared with the control group (22°). The mean femoral version of the study group was 19°; for male patients, 15°; and for female patients, 22°. CONCLUSION Abnormalities in femoral version are highly prevalent in patients with hip pain who are eligible for hip preservation surgery, and severe abnormalities are prevalent in 1 of 6 patients (17%). Based on these results, the evaluation of young patients with hip pain should always include an assessment of femoral version and acetabular version to best decide what treatment approach should be undertaken to optimize outcomes