O2121: Patient Age, Petrie Casting, and Patient-reported Quality of Life Measures Are Associated with Adherence to Wide-abduction Brace Treatment for Legg-calvé-perthes Disease

Background: A wide-abduction brace called the A-frame brace is commonly used to contain the deformed femoral head to improve hip abduction and femoral head remodeling in patients with Legg-Calvé-Perthes disease (LCPD). While there is evidence 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 (STU 112015-009) of LCPD patients treated with A-frame brace between ages 5 and 11. Brace wear was measured using built-in temperature sensors (Figure 1). Patient clinical history was obtained via chart review. Quality of life during brace treatment was assessed via Patient-Reported Outcomes Measurement Information System (PROMIS) surveys administered during clinic visit. Pearson correlation coefficient and multivariate 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 mean age at initiation of brace treatment was 7.1±1.5 years. Fifty-eight patients (95%) were in the fragmentation or re-ossification 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 prior to 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 (r = -0.39, p < 0.005). Adherence was negatively associated with patient-reported depressive symptoms (r = -0.30, p < 0.05), anxiety (r = -0.25, p < 0.05), and pain interference (r = -0.25, p < 0.05). Adherence was not significantly associated with gender, ADHD, patient-reported anger, or peer relationship issues.

Conclusion: A-frame brace adherence was significantly associated with age at treatment, prior Petrie casting, and patient-reported depressive symptoms, anxiety, and pain interference. These findings provide new insight into A-frame brace treatment which will lead to better patient selection and counseling to optimize adherence.