Predictors of osteoarthritis following operative treatment of medial tibial plateau fractures.

PURPOSE: To determine factors influencing the development of posttraumatic osteoarthritis (OA) following medial tibial plateau fractures and to evaluate concomitant injuries associated with these fractures.

MATERIALS AND METHODS: A chart review of patients with operatively treated medial tibial plateau fractures admitted to our Level I trauma centre from 2002 to 2008 was performed. Of 63 patients, 41 participated in a clinical and radiographic examination. The mean age was 47 years (range 16-78) and the mean follow-up time was 7.6 (range 4.7-11.7) years. All patients had preoperative computed tomography (CT) scans and postoperative radiographs. At the end of follow-up, standing radiographs, mechanical axis, and CT scans were evaluated.

RESULTS: Of the 41 patients, 24 had no or mild (Kellgren-Lawrence grade 0-2) OA and 17 had severe (grade 3-4) OA. Initial articular depression measured from preoperative CT scans was a significant predictor of OA (median 1.8mm vs 4.5mm, p=0.009). Fracture line extension to the lateral plateau (p=0.68) or fracture comminution (p=0.21) had no effect on the development of posttraumatic OA, nor did articular depression at the end of follow-up (p=0.68) measured from CT scans. Mechanical axis >4° of varus and ≥2mm articular depression or step-off were associated with worse WOMAC pain scores, but did not affect other functional outcome scores. Six patients (10%) had permanent peroneal nerve dysfunction. Ten patients (16%) required LCL reconstruction and nine (14%) ACL avulsions were treated at the time of fracture stabilisation.

CONCLUSIONS: The amount of articular depression measured from preoperative CT scans seems to predict the development of posttraumatic OA, probably reflecting the severity of chondral injury at the time of fracture. Restoration of mechanical axis and articular congruence are important in achieving a good clinical outcome.