Central Femoral Head Chondromalacia Is Associated with a Diagnosis of Hip Instability.

Purpose: To compare the locations and patterns of femoral head chondral damage in patients with instability in contrast to those with femoroacetabular impingement (FAI) without instability. Methods: All consecutive hip arthroscopies were reviewed from 2013 to 2020 from a single surgeon. Intraoperative records were reviewed on all patients identified to have femoral head chondromalacia. Data were collected to include laterality, location of femoral head chondromalacia, intraoperative diagnosis (instability and/or FAI subtype), and ease of distractibility. The location of the femoral head chondromalacia was defined on the basis of intraoperative description. Chi-squared and Fisher's exact tests were used for categorical variables, and a two-sample Results: A total of 64 patients were in the study cohort, with 32 patients identified as having non-central head chondromalacia and 32 patients identified as having central head chondromalacia. Of the patients with central head chondromalacia, 81% were diagnosed with instability. Central head chondromalacia was associated with a sensitivity of 84% (71%-97%), specificity of 82% (69%-95%), and positive predictive value of 81% (67%-95%). Conclusions: A high percentage of patients with central femoral head chondromalacia were found to have hip microinstability. These results suggest that there is a pattern of femoral head chondral damage in patients with hip microinstability. Level of Evidence: Level III, case-control study.