Pathoanatomy and clinical outcomes following operative treatment of supination adduction type II medial malleolus fractures-a cohort study.

BACKGROUND

The purpose of the current study was to retrospectively clarify the anatomic character and evaluate the mid-term operative outcomes for vertical medial malleolar fractures (MMFs).

METHODS

A total of 53 patients with supination adduction (SAD) type II MMFs treated with open reduction and internal fixation (ORIF) between March 2009 and June 2013 were included. We reviewed the patients' preoperative X-ray and computed tomography (CT) to determine the pathoanatomic characteristics of medial malleolus fractures. Buttress plate lag screws fixation had been applied. Complications and treatment failures were recorded; the American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot score and the visual analogue scale (VAS) were used to evaluate the functional outcomes.

RESULTS

For the 53 patients, only 39.6% cases with simple vertical MMFs. The mean distal tibial articular surface (DTAS) involvement in the MMF was 16.5%±11.6% (range, 0-47%). The mean follow up time was 62.4±14.1 [44-91] months. There were 7 cases of traumatic osteoarthritis (TOA), and 3 cases of failure were reported in the screw fixation group. The mean AOFAS score was 80.6±15.8 points, and the mean VAS score was 2.1±1.7 points, with a good to excellent rate (GTE) of 81.1%. No significant difference was found in comparing the AOFAS, VAS, GTE, incision relative complication rate, infection rate, loss of reduction (LoR) rate, and TOA rate between groups (P>0.05). The participants in the buttress plate group reached a shorter mean full weight-bearing (FWB) time (P=0.04).

CONCLUSIONS

More than 60% vertical MMFs are with one or more characteristics of medial cortex comminuted fractures, or die-punch fragments, or medial joint compression. And patients with die-punch fragment, medial joint compression, LoR, large DTAS involvement and small fracture line angle (FLA) were positively correlated with the fair to poor results. Lag screw fixation should be cautiously used in vertical MMF patients with comminuted medial cortex.