Collateral ligament injury in the displaced radial head and neck fracture: correlation with fracture morphology and management strategy to the torn ulnar collateral ligament.

Background: The purpose of our study was to correlate the morphology of displaced radial head and neck (DRHN) fractures with associated ligament injuries and evaluate the outcomes of management of the torn ulnar collateral ligament (UCL).

Methods: Twenty-nine surgically treated patients presenting with a DRHN fracture were classified using the Charalambous classification by 3-dimensional computed tomography. Accordingly, the collateral ligament and overlying muscle injuries and bony contusions were investigated with magnetic resonance imaging. The valgus stress test was performed intraoperatively on 20 patients with magnetic resonance-confirmed complete UCL rupture. If there was no firm end point, the UCL was repaired (group B). The others were treated conservatively (group A). The Minnesota Elbow Performance Score and Disabilities of the Arm, Shoulder and Hand scores were used to measure patient outcome.

Results: There was a trend toward a higher incidence of complete UCL rupture in Charalambous type 3D and 4D fractures (P = .110) and complete lateral UCL rupture in Charalambous type 1D and 2D fractures (P = .126), although this was not statistically significant. Rupture of the overlying muscles was more common in group B than in group A (P < .05). Functional outcome between the 2 groups was not significantly different.

Conclusions: DRHN fracture is always a complex fracture accompanied by collateral ligament injuries. Type 3D and 4D tended to have a higher association with UCL rupture compared with type 1D and 2D, types commonly associated with lateral UCL rupture. The magnetic resonance imaging-confirmed torn UCL could be managed conservatively if there was a firm end point on valgus stress test.