Fragment Incarceration as a Key Determinant of Functional Outcomes After Operative Fixation of Pediatric Medial Epicondyle Fractures: A Single-center Retrospective Cohort Study

Background: Medial epicondyle fractures account for a substantial proportion of pediatric elbow injuries, but the determinants of functional outcome after operative fixation remain incompletely defined. This study sought to describe functional and radiographic outcomes after open reduction and internal fixation (ORIF) of pediatric medial epicondyle fractures and to identify clinical, injury-related, and treatment-related parameters associated with these outcomes. Methods: We retrospectively reviewed consecutive patients 16 years or younger who underwent ORIF for isolated medial epicondyle fractures between 2018 and 2024, with ≥12 months of follow-up. Fixation was performed with either Kirschner wires (KW) or a cannulated lag screw (LS) with washer. Outcomes at final review included Mayo Elbow Performance Score (MEPS), elbow flexion–extension range of motion (ROM), and forearm rotation range (ROR). Fragment incarceration, preoperative ulnar nerve involvement, complications, and time to radiographic union were recorded. Univariate analyses and multivariable linear regression were used to identify factors associated with MEPS, ROM, and ROR. Results: Thirty-nine patients were included (KW, n = 22; LS, n = 17; mean age = 12.4 y). The mean time for radiographic union was 5.4 weeks. At final follow-up, mean MEPS was 91.9, ROM 133.9 degrees, and ROR 156.8 degrees. Fragment incarceration occurred in 11 patients (28%), and preoperative ulnar nerve involvement in 4 (10%). In multivariable analysis, fragment incarceration was independently associated with lower MEPS and reduced ROM, whereas KW fixation was associated with a small absolute difference of approximately 3 to 4 MEPS points on the 0 to 100 scale compared with LS. No variable significantly predicted ROR. Conclusions: Both K-wire and cannulated lag screw with washer fixation achieved early union and generally excellent function after pediatric medial epicondyle fractures. Within this cohort, fragment incarceration appeared more strongly related to residual functional loss than implant type, supporting individualized implant selection and suggesting that careful attention to reduction, fixation stability, and a protocol-driven early mobilization program may be particularly important when incarceration is present. Level of Evidence: Level III, retrospective cohort study.