Acetabular dysplasia: a paradigm of arthroscopic examination of chondral injuries.

The current authors show the value of arthroscopy in diagnosing labral and acetabular cartilage injury and examining the relationship between those injuries and acetabular dysplasia. Between 1989 and 2000, 170 hips in 163 patients with mild acetabular dysplasia or moderate dysplasia with joint preservation had arthroscopic evaluation. Surgical findings were classified by location and by severity of the chondral lesions of the femoral head, acetabulum, and labrum. Of the 170 hips with dysplasia, 122 had labral tears (72%) at the free-margin articular surface and 113 had anterior tears (66%). One hundred hips (59%) had anterior acetabular chondral lesions. Among the 113 patients who had anterior labral tears, 78 hips (69%) had anterior acetabular chondral defects, and 44 hips (39%) had anterior femoral head chondral lesions. Mild uncovering of the anterior femoral head subjects the labrum to increased load and potential susceptibility to tearing most frequently anteriorly. Labral tears may contribute to or can occur in association with articular cartilage lesions of the contiguous femoral head or acetabulum. The mechanism of injury is most likely hyperextension or torque of the hip or both. The findings in the current study support the concept that labral disruption frequently is a predecessor in the continuum of degenerative joint disease.