Crista supinatoris fractures of the proximal part of the ulna.

BACKGROUND

The crista supinatoris is the insertion site of the lateral collateral ligament complex on the proximal part of the ulna. The purpose of this study was to report the presentation, management, and outcomes of patients with crista supinatoris fractures.

METHODS

Twelve patients with fractures of the crista supinatoris were assessed clinically and radiographically and with validated outcomes at a mean of thirty-nine months after injury. Outcome measures included the Patient-Rated Elbow Evaluation (PREE), Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, American Shoulder and Elbow Surgeons elbow (ASES-e) score, and strength measured with a dynamometer.

RESULTS

No crista supinatoris fracture occurred in isolation. Other associated injuries included radial head fracture in ten patients (83%), a radial neck fracture in one patient, and a capitellar fracture in one. At the time of presentation, all crista factures were difficult to identify on standard radiographs, but oblique radiographs and/or computed tomography (CT) allowed definitive fracture identification. Four patients were managed nonoperatively, and eight patients were managed surgically, with the indication for surgery being the associated injuries, not specifically the presence of a crista fracture. At the time of surgery, posterolateral rotatory elbow instability, if present, was due to the crista fracture. At the time of follow-up, all elbows were clinically stable and had radiographic concentric reductions. Elbow flexion and extension were a mean (and standard deviation) of 136° ± 6° and 5° ± 8°, respectively. The mean PREE score was 15 ± 20, and the mean DASH was 13.5 ± 18.

CONCLUSIONS

Crista supinatoris fractures are difficult to identify on standard elbow radiographs. Fracture management is based on an assessment of elbow stability and on appropriate treatment of the associated injuries.