Pediatric Medial Humeral Condyle Fractures: Classification, Treatment, and Outcomes.

Background: The purpose of this study was to develop and validate a classification system that describes the injury pattern of pediatric medial humeral condyle fractures and provide treatment guidelines.

Methods: Patients less than 18 years old with medial humeral condyle fractures from 2012 to 2022 were identified. A classification system was developed based on fracture pattern and putative mechanism of injury. Type 1 fractures were characterized by a valgus/avulsion type injury while type 2 fractures were characterized by a vertical shear pattern. Each type was subdivided by amount of fragment displacement: (A) nondisplaced or minimally displaced (<2 mm) versus (B) displaced (>2 mm). Three attending orthopaedic surgeons evaluated and classified each patient's fracture. Intrarater and inter-rater reliability was calculated with Kappa statistics.

Results: Twenty-seven patients (16 males) with an mean age of 10.5 years were included. There were 4 type 1A, 17 type 1B, and 6 type 2B fractures with substantial agreement in inter-rater (ĸ=0.62, CI=0.45-0.78), and intrarater (mean ĸ=0.79, range=0.70-0.93) reliability analysis. Surgical treatment was performed in 25/27 patients; 4 patients underwent closed reduction percutaneous pinning (CRPP) and 21 underwent open reduction and internal fixation (ORIF). Ten patients required advanced imaging to assist in surgical decision making. Both nonoperative patients had type 1A fractures. Nearly one-fourth of patients (6/27, 22%) had some functional loss of motion and poor outcomes based on Flynn's criteria, with a Fisher exact test revealing an increased risk of functional loss of motion in skeletally mature children ( P =0.02). Two patients had complications including 1 nonunion after initial nonoperative management (type 1B) and 1 patient (type 2B) required manipulation under anesthesia for postoperative stiffness.

Conclusion: Moderate to strong inter-rater and intrarater reliability was demonstrated with the proposed classification system. Type 1A fractures are amenable to nonoperative treatment while types 1B and 2B require surgical management. Skeletally mature patients may be at greater risk of motion loss following injury.

Level of evidence: Level IV-case series.