Patient Adherence to Wide Abduction Brace Treatment for Legg-Calvé-Perthes Disease

Background: A wide abduction brace called the A-frame brace is used to contain the deformed femoral head and improve femoral head remodeling in patients with Legg-Calvé-Perthes disease (LCPD). While there is some data showing the efficacy of brace treatment, little is known about patient adherence. The purpose of this study was to measure A-frame brace adherence using temperature sensors and to identify factors that influence adherence. Methods: This is an IRB-approved retrospective study of 61 patients with LCPD treated with an A-frame brace between ages 5 and 11. Brace wear was measured using built-in temperature sensors. Pearson correlation coefficient and multiple regression were used to determine relationships between patient characteristics and brace adherence. Results: Of 61 patients, 80% were male. Mean age at LCPD onset was 5.9±1.8 years and the mean age at initiation of brace treatment was 7.1±1.5 years. Fifty-eight patients (95%) were in the fragmentation or reossification stage at the start of bracing, with 23 patients (38%) having lateral pillar B, 7 (11%) lateral pillar B/C, and 31 (51%) lateral pillar C. Forty-two (69%) patients were treated with a Petrie cast for 6 weeks before the A-frame brace. Mean adherence, defined as the ratio of measured over prescribed brace wear, was 0.69±0.32. Mean adherence improved with age (P<0.05), increasing from 0.57 in patients less than 6 to 0.84 in patients aged 8 to 11. Patients first treated with a Petrie cast had significantly better adherence than those without (0.77 vs. 0.50; P<0.005). Adherence was negatively associated with the amount of prescribed brace wear per day (P<0.005). Adherence did not change significantly between the start and end of treatment and was not significantly associated with sex or attention deficit hyperactivity disorder. Conclusions: A-frame brace adherence was significantly associated with age at treatment, prior Petrie casting, and the amount of daily prescribed brace wear. These findings provide new insight into A-frame brace treatment, which will lead to better patient selection and counseling to optimize adherence. Level of Evidence: III Therapeutic Study.