Controlled Ankle Movement (CAM) Boot Provides Improved Outcomes With Lower Complications Than Short Leg Walking Cast in Low-energy Pediatric Lateral Ankle Injuries: A Prospective, Randomized Study

Background: Low-energy lateral ankle injuries (Salter-Harris 1 distal fibula, distal fibula avulsion fractures, and radiograph-negative lateral ankle injuries) are common in pediatric patients. Patient-based outcomes for the 2 treatment options, short leg walking cast (CAST) and controlled ankle motion (CAM) boot, are unknown. This study aims to determine differences between 2 treatments of low-energy lateral ankle injuries in pediatric patients.

Methods: A prospective, randomized controlled trial comparing the acute outcomes of CAST and CAM treatment for low-energy lateral ankle injuries in pediatric patients was completed. Patients were evaluated in-person at presentation and 4 weeks for ankle range of motion and Oxford foot and ankle score. A novel survey defining patient and parent satisfaction and time away from school/work was also completed. Treatment complications were documented. Patients were called at 8 weeks postinjury to determine other complications and the final time of return to sport. Mixed effects linear regression models evaluated change over time between the 2 treatment groups.

Results: After 60 patients were enrolled, 28 patients in the CAST group and 27 patients in the CAM group completed the study. Males comprised 51% (28), with 38 (69%) patients identifying as Hispanic. The patient's average age was 11.3±2.9 years and the average body mass index was 23.At the 4-week evaluation, the CAM group had improved range of motion, higher satisfaction scores (5.26 CAM vs. 4.25 CAST, P <0.05), similar pain scores (0.32 CAST vs. 0.41 CAM, P =0.75), and lower complications (0.54/patient CAST vs. 0.04/patient CAM, P <0.0001) than the CAST group. Female patients had improved inversion with CAM treatment than males ( P <0.05). Patients over age 12 in the CAST group had significantly decreased plantarflexion at week 4 ( P =0.002). Improvement in Oxford scores was similar between the CAST and CAM groups between the initial presentation and 4 weeks, except for increased improvement in CAM group Oxford scores for difficulty running and symptoms with walking/walking. At the 8-week evaluation, patients in the CAST group had a higher rate of continued symptoms than the CAM group (15.4% vs. 0%).

Conclusions: CAM boot treatment of low-energy lateral ankle injuries in pediatric patients results in improved results and lower complications than CAST treatment.

Level of evidence: Level I -randomized, controlled trial with a statistically significant difference.