Risk Factors and Surgical Sequelae of Physeal Arrest in Pediatric Salter-Harris III and IV Medial Malleolus Fractures.

BACKGROUND

Pediatric medial malleolus fractures pose a risk for physeal bar formation and growth disturbances. This study aimed to determine the rate of physeal bar formation following Salter-Harris (SH) III or IV medial malleolus fractures and identify patient, fracture, and management factors predictive of bar formation. A secondary objective was to evaluate the rate of additional surgeries required in the event of physeal bar formation.

METHODS

A retrospective review was performed of 161 patients (age 16 y or younger) with isolated medial malleolus or bimalleolar fractures. Fifty-six skeletally immature patients (39% female) with SH III or IV medial malleolus fractures and ≥6 months of radiographic follow-up met the inclusion criteria. Demographics, injury mechanism, fracture management, and secondary surgeries were recorded. Radiographs were analyzed for fracture displacement, SH classification, coronal plane physeal involvement, anterior and lateral distal tibial angles, postreduction displacement, and physeal bar formation. Wilcoxon rank sum tests assessed statistical significance (α<0.05).

RESULTS

Thirty-five isolated medial malleolus and 21 bimalleolar ankle fractures were identified (SH III=40, SH IV=16). Initial treatment was operative in 34 patients (60.7%), with greater fracture displacement (4.9 vs. 2.4 mm) and coronal plane physeal involvement (21.5% vs. 16.4%) being significant predictors of surgical management. Physeal bars developed in 17 patients (30.4%), with a mean diagnosis time of 8.4 months. Patients with bar formation also presented with significantly greater fracture displacement (5.4 vs. 3.3 mm) and coronal plane physeal involvement (23.6% vs. 17.8%). No difference in bar formation rates was observed among other patient or fracture characteristics. Eight of 17 physeal bar patients (47%) required at least one secondary surgery, including bar resection (n=4), epiphysiodesis (n=7), and/or osteotomies (n=3).

CONCLUSIONS

Pediatric physeal medial malleolus fractures carry a high risk for bar formation. Greater fracture displacement and coronal plane physeal involvement were significant predictors of initial surgical management and bar formation. Close radiographic monitoring of these high-risk fractures for at least 1 year following injury and attentive patient counseling on the risk of secondary surgery is recommended for timely identification and intervention.

LEVEL OF EVIDENCE: Level IV-case series.