Parafoveal chondral lesion of the femoral head in patients with femoroacetabular impingement.

Objective: To describe cases of parafoveal chondral lesion of the femoral head in patients with femoroacetabular impingement, correlating the clinical and imaging data.

Materials and methods: This was a retrospective descriptive case series of parafoveal chondral lesion of the femoral head in 21 patients who underwent computed tomography and magnetic resonance arthrography scans of the hip, having then received an imaging-based diagnosis of femoroacetabular impingement.

Results: Of the 21 patients evaluated, 15 (71%) had cam-type femoroacetabular impingement, whereas five (24%) had mixed-type impingement, and one (5%) had pincer-type impingement. Twelve patients (57%) had a low frequency of physical activity, which was significantly associated with the presence of cam-type impingement (p = 0.015). Although the extent of the lesion correlated significantly with the acetabular coverage angle (p = 0.04), it did not correlate significantly with the alpha angle or femoral head-neck offset value (p = 0.08 and p = 0.06, respectively). We also found no correlation between the extent of the lesion and the other main parameters that define the femoroacetabular impingement types.

Conclusion: This was one of the largest case series of parafoveal chondral lesion of the femoral head in patients with imaging findings of femoroacetabular impingement. The extent of such lesions does not appear to correlate with the parameters of femoroacetabular impingement, with the exception of the acetabular coverage angle.