Minimally Displaced Humeral Lateral Condyle Fractures: Immobilize or Operate When Stability is Unclear?

Background: Either casting or in situ fixation (to prevent displacement) are recommended for minimally displaced pediatric lateral condyle fractures of indeterminate stability with ≤2 mm lateral displacement and narrowed fracture extension to the epiphyseal articular cartilage. This study compares casting only, acute prophylactic in situ pinning, and surgery if casting fails due to displacement. Methods: In total, 738 fractures at a level 1 trauma center between 2008 and 2014 were reviewed. All fractures were assigned a Song classification and Song 2 fractures followed to union were analyzed. Worsening displacement was defined as an increase in Song stage. Patients were grouped per treatment: (1) cast only; (2) in situ pinning; or (3) closed or open reduction percutaneous pinning after displacement during attempted cast treatment. Results: In total, 139 fractures were included and 45 (32%) underwent surgery. Among 114 fractures intended for casting, only 20 (18%) displaced and needed surgery. This implies 82% of fractures prophylactically pinned in situ may have remained stable in a cast. On average, displaced fractures were noted 6.5 (2 to 13) days after presentation and required 1 extra clinic visit and week of immobilization without increased complications. Surgeons chose open reduction percutaneous pinning more often for displaced fractures. Conclusions: Our data estimate 82% of Song 2 fractures never meaningfully displace in a cast. Meaningful displacements occur in <2 weeks. Benefits of prophylactic pinning include 1 less x-ray and clinic visit in exchange for a clinically insignificant lateral cortex reduction and inherent surgical risks. Compliance, surgical scheduling, and a higher rate of open reduction after displacement should influence early treatment decisions. Level of Evidence: Level III.