Comparison of lag screw versus buttress plate fixation of posterior malleolar fractures.

BACKGROUND: The goal of this study was to report the results of selective open reduction and internal fixation of fractures of the posterior malleolus with a posterolateral approach and to compare the results of the 2 techniques.

METHODS: We prospectively evaluated 40 patients who underwent posterior malleolar fracture fixation between 2008 and 2012. The patients were treated with a posterolateral approach. We assigned alternating patients to receive plate fixation and the next screw fixation, consecutively, based on the order in which they presented to our institution. Fixation of the posterior malleolus was made with lag screws in 20 patients and a buttress plate in 20 patients. We used American Orthopaedic Foot and Ankle Society (AOFAS) scores, range of motion (ROM) of the ankle, and radiographic evaluations as the main outcome measurements. The mean follow-up was 38.2 (range, 24-51) months.

RESULTS: Full union without any loss of reduction was obtained in 38 of the 40 patients. We detected a union with a step-off of 3 mm in 1 patient in the screw group and a step-off of 2 mm in 1 patient in the plate group. At the final follow-up, the mean AOFAS score of the patients regardless of fixation type was 94.1 (range, 85-100). The statistical results showed no significant difference between the patients regardless of the fixation type of the posterior malleolus in terms of AOFAS scores and ROM of the ankle (P > .05).

CONCLUSIONS: Good (AOFAS score of 94/100) and equivalent (within 3 points) results were obtained using the 2 techniques (screws or plate) for fixation after open reduction of posterior malleolar fragments.

LEVEL OF EVIDENCE: Level II, prospective case series.