Abstract
Objectives:
The role of femoral version (FV[MOU1] ) in the pre-arthritic hip pain remains increasingly recognized, including in femoroacetabular impingement (FAI). Increased femoral version or decreased femoral version may play a role in hip biomechanics contributing to hip instability or impingement, respectively. The purpose of this study was to compare the outcomes of hip arthroscopy for FAI across different femoral version groups in a multicenter prospective cohort study.
Methods:
A prospective multicenter cohort study of 677 FAI patients undergoing primary hip arthroscopy was performed. The current study included 603 patients with low-dose CT performed preoperatively for measurement of femoral version from the larger cohort. Inclusion criteria were patients aged 14-45 years with idiopathic FAI. Exclusion criteria were previous ipsilateral hip procedures, associated disorders, or Tönnis 2 or greater osteoarthritis. Femoral version was measured on low-dose computed tomography (CT) utilizing the Yoshioka oblique method and was broken into five subgroups: <5° (decreased FV), 6-15° (normal FV), 16-25° (mildly increased FV), 26-35° (moderately increased FV), 35°+ (severely increased FV). Patient-reported outcomes (PROs) were measured at a minimum one-year follow-up. The modified Harris hip score (mHHS) was assessed relative to the minimal clinically important difference (MCID) of 8 and patient acceptable symptom state (PASS) of 74. Additional PROs included the HOOS Pain and Sports/Recreation subscores and the iHOT-12 score. Composite failure was defined as a reoperation for persistent symptoms or a failure to achieve either the mHHS MCID or PASS. Independent t-test (Mann-Whitney U) and ANOVA were utilized to compare groups.
Results:
Males had statistically lower femoral version than females (14.0° vs 18.0°; p<0.001). In females, 38.0% had mildly increased FV, 17.9% had moderately increased FV, and 3.6% had severely elevated FV. This is compared to 27.6%, 9.2%, and 1.8% in males, respectively (all p<0.001). Decreased FV was present in 7.1% of males, compared to 5.9% of females. Increased or decreased femoral versions appear to have similar outcomes to normal version when evaluated by PROs or outcome states. In fact, mildly increased and moderate increased FV group demonstrated the best outcomes. Changes in HOOS pain and sports subscores were significantly higher for these groups. Severely increased FV, >35°, was only present in 2.8% of patients but did demonstrate a higher rate of composite failure (15.4%) compared to moderately increased FV (3.1%). The decreased FV group had a composite failure of 10.4% compared to normal femoral version, 16-25° (10.2%).
Conclusions:
In a patient cohort undergoing hip arthroscopy for FAI, significant differences in FV between males and females were present. Overall, in a multicenter prospective cohort study, the outcomes of hip arthroscopy for FAI did not seem to differ between increased or decreased femoral versions but were superior in mild to moderately increased FV. Future research with longer-term follow-up is still needed to definitively establish the longevity of outcomes of hip arthroscopy relative to FV.
