Clinical and Radiographic Predictors of Acetabular Cartilage Lesions in Adolescents Undergoing Hip Arthroscopy.

ABSTRACT

BACKGROUND: Acetabular cartilage lesions are a known cause of poor outcomes after hip arthroscopy and are seen regularly among adolescents. However, studies identifying preoperative factors predictive of acetabular cartilage lesions have been limited to adult populations. PURPOSE: To assess clinical and radiographic predictors of acetabular cartilage lesions in a large cohort of adolescents undergoing hip arthroscopy. STUDY DESIGN: Cohort study (Diagnosis); Level of evidence, 3. METHODS: Patients undergoing hip arthroscopy for idiopathic femoroacetabular impingement or acetabular labral tears at a children's hospital were reviewed. Demographic predictors were analyzed by use of univariate logistic regression with generalized estimating equations. A matched case-control analysis was subsequently performed to identify radiographic predictors of acetabular cartilage lesions through use of univariate and multivariable conditional logistic regression. RESULTS: Four hundred two patients (446 hips) undergoing hip arthroscopy between 2010 and 2015 were analyzed. Median age was 16.7 years (range, 13.6-19.0) and 72% of patients were female. Ninety-five hips (21%) were found to have an acetabular cartilage lesion at the time of arthroscopic surgery. Age (odds ratio [OR], 1.7; 95% CI, 1.4-2.1), male sex (OR, 2.5; 95% CI, 1.7-5.0), and body mass index (OR, 1.07; 95% CI, 1.01-1.14) were found to be predictive of intraoperative acetabular cartilage lesions. In the matched case-control analysis, femoral alpha angle as calculated on a Dunn lateral radiograph was independently predictive of an intraoperative acetabular cartilage lesion (OR, 1.8; 95% CI, 1.2-2.6). Additionally, the presence of a crossover sign was independently associated with a decreased odds of an acetabular cartilage lesion (OR, 0.3; 95% CI, 0.1-0.7). On multivariate analysis, alpha angle (Dunn lateral) (OR, 2.0; 95% CI, 1.3-3.1) and crossover sign (OR, 0.2; 95% CI, 0.1-0.7) remained independently associated with the presence of an acetabular cartilage lesion. The presence of an acetabular labral tear was not predictive of an associated cartilage lesion (OR, 1.17; 95% CI, 0.39-3.47; P = .78). CONCLUSION: In an adolescent population undergoing hip arthroscopy, older age, male sex, and higher body mass index were predictive of acetabular cartilage lesions. From an imaging standpoint, increased alpha angle increased the likelihood of an acetabular cartilage lesion whereas the presence of a crossover sign decreased this likelihood. Predicting the presence of an acetabular cartilage lesion is important when considering a hip arthroscopy procedure to facilitate preoperative planning and to more accurately set patient expectations.