To identify hip pathology patterns according to gender, alpha angle deformity and generalized ligamentous laxity (GLL) in a non-arthritic patient population following primary hip arthroscopy for femoroacetabular impingement syndrome.
Patients who underwent primary hip arthroscopy between February 2008 and February 2017 were included and separated into males and females for initial analysis. The demographics, radiographic findings, intraoperative findings, and surgical procedures were then compared. A threshold of one standard deviation above the mean alpha angle in the male group was used to create two sub-groups. For females, GLL based on a Beighton’s score ≥4 was used to divide the group.
A total of 2701 hips were included. Of those, 994 hips were in the male group and 1707 hips in the female group. Mean age was 36.6 years±13.8 and 37.1 years±15.0 for the male and female groups, respectively. The male group had a higher average alpha angle when compared to females [65.9°±11.9 vs 58.4°±10.8 (P<0.001)]. GLL was more common in females than males (P< 0.001). The male group had a higher proportion of acetabular Outerbridge grade 3 and 4 lesions compared to the female group (P<0.0001). Males in the alpha angle ≥78° sub-group reported higher rates of acetabular Outerbridge grade 4 damage than males in the <78° one (P<0.0001). Mean lateral center-edge angle was lower in the Beighton ≥4 female sub-group [23.7°±4.2 versus 31.3°±5.8 (P<0.0001)].
Two different patterns of hip pathologies were found to be related to gender. On average, male patients had higher alpha angles and increased acetabular chondral damage when compared to the females. A larger cam-type anatomy was associated with more severe acetabular chondral damage in males. In the female group, the incidence of features of hip instability such as GLL were significantly higher than in the male group.