Monica Shoji - Harvard Combined Orthopaedic Residency Program, Harvard Medical School, Boston, MA, USA
Magdalena Hartwich Garcen - Orthopedics and Traumatology Department, British Hospital, Montevideo, Uruguay
Alberto A. Fernandez Dell’Oca - Orthopedics and Traumatology Department, British Hospital, Montevideo, Uruguay
Jesse Jupiter - Department of Orthopaedic Surgery, Division of Hand and Upper Extremity Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA

Background: The purpose of this case series is to describe surgical decision making and clinical outcomes in posteriorly displaced radial head fractures with a major fragment (more than ۵۰% of the head) located behind the humeral condyle. We also document the outcome of open reduction and internal fixation of completely displaced radial head fractures.Methods: A retrospective review of the ICUC® (Integrated Comprehensive Unchanged Complete) database was performed between ۲۰۱۲ and ۲۰۲۰. Patients were included if preoperative radiographs demonstrated a major radial head fracture fragment located posterior to the humeral condyle and a minimum of ۲-year follow-up data was available. Results: Ten patients met inclusion criteria. Two patients had an associated elbow dislocation whereas ۸ patients did not. All patients were found to have disruption of the lateral collateral ligament complex intraoperatively. Nine radial head fractures were successfully fixed with interfragmentary screws. One multi-fragmented radial head fracture could not be successfully stabilized with interfragmentary screw fixation and was resected. The average time to final followup was ۴.۸ years (range ۲.۲-۸.۱). At final follow-up, ۶ patients demonstrated radiographic evidence of a healed radial head, ۱ patient had avascular necrosis, and ۲ had post-traumatic arthritis. None demonstrated radiographic instability. The average functional score was ۰.۶۴ (SD ۰.۸۱) and pain score was ۰.۴۵ (SD ۰.۹۳). The average elbow extension was ۸ degrees (SD ۱۱), elbow flexion was ۱۳۹ degrees (SD ۶), forearm supination was ۶۰ degrees (SD ۲۷), and forearm pronation was ۶۹ degrees (SD ۳).Conclusion: Recognition of a posteriorly displaced radial head fracture is essential, as it may be an indirect sign of elbow instability. This instability should be addressed during surgical intervention. Level of evidence: IV

Elbow, elbow dislocation, Trauma, radial head fracture