Defining Successful Radiographic Physeal Arrest: A Comparison Between Ulnar Epiphysiodesis With and Without a Sliding Bone Autograft.

Background: Distal radius physeal injuries can result in growth arrest and progressive deformity in children. Ulnar epiphysiodesis may be used to prevent deformity in the skeletally immature child; however, predicting success may be challenging. The purpose of this study was to (1) develop a method to predict successful ulnar epiphysiodesis, and (2) determine the utility of adding a sliding bone autograft as an adjunct to achieving successful epiphysiodesis.

Methods: A radiographic assessment of children who underwent isolated ulnar epiphysiodesis for premature radial physeal closure at a single institution was performed, evaluating ulnar variance measurements pre-op, immediate post-op, time of physeal arrest, and final ulnar variance. Surgical technique, including ulnar epiphysiodesis with and without adjunctive sliding bone autograft, was recorded to develop two cohorts to compare the duration of successful physeal closure based on the methodology developed.

Results: Eighty-seven wrists met the criteria (age 14.1±1.3 y) with an overall radiographic success of 99% with a mean radiographic follow-up of 6.6±5.9 months. Fifty-four wrists had repeat radiographs after defined radiographic physeal closure to confirm that when >50% of the ulnar physis demonstrated bridging bone formation, there was a longitudinal cessation of growth in 100% of these patients. Forty-five children had ulnar epiphysiodesis without bone graft, and 42 had ulnar epiphysiodesis with adjunct sliding bone autograft. Time to radiographic physeal arrest in the sliding bone autograft cohort was 1.3±0.7 (0.6 to 3.7) months compared with those without a bone graft of 2.9±2.2 (0.7 to 8.3) months; P<0.001.

Conclusions: Greater than 50% of opacity across the ulnar physis reliably indicates a successful arrest following ulnar epiphysiodesis. Although the adjunct of a sliding bone autograft did not significantly change the ability to achieve an arrest, it did reduce the duration of time to achieve the arrest. The metric of 50% opacity as a marker for successful cessation of growth can be adapted to limit additional follow-up radiographs. Ulna epiphysiodesis with adjunct sliding bone autograft can be employed when faster cessation is needed.

Level of evidence: Level III-comparative study.