Screw Fixation of the Posterior Malleolus Fragment in Ankle Fracture: Cadaveric and Clinical Studies

Abstract

Category: Ankle, Trauma Introduction/Purpose: Previously, a posterior malleolus fragment (PMF) covering 25–30% of the articular surface was a known indication for surgical fixation for ankle fractures. This study aimed to compare the outcomes of screw fixation for PMF comprising <25% of the articular surface and to evaluate the results of cadaver experiments. Methods: The clinical study enrolled ankle fracture patients with PMFs who planned to undergo surgery between March 2014 and February 2017. Among them, 62 with type 1 PMF comprising <25% of the articular surface were included: 32 patients underwent cannulated screw fixation for PMF after fixation for lateral and/or medial malleolar fracture (A group), whereas the other 30 patients underwent internal fixation for lateral and/or medial malleolar fracture but no screw fixation (B group). Clinical outcomes were determined at the 3-, 6-, 12-, and 18-month visits. Additionally, cadaver studies were conducted to evaluate cannulated screw fixation or no fixation in cases of PMFs comprising <25% of the articular surface and >1 mm displacement. Ankle joint stability was measured under external torque on the ankle in the neutral position. The level of significance was set at P < .05. Results: Clinical outcomes at 6 and 12 months after surgery were significantly higher in group A than in group B. However, there was no significant intergroup difference in clinical outcomes at 18 months of follow-up. In the cadaver study, PMF screw fixations were significantly more stable under external rotation force. Conclusion: Screw fixation was significantly useful during early recovery and in short-term clinical outcomes owing to stabilization of ankle fractures with PMF involving <25% of the articular surface.

Trimalleolar fracture: The endless posterior malleolus fracture debate, to repair or not to repair?

“…Another recent prospective comparative study argued that the fragment size has negligible effects on the outcome. 33 The authors evaluated the outcomes of 62 patients sustaining ankle fractures with PMF involving <25% of articular surface. All patients underwent ORIF of lateral and/or medial malleoli fixation, of them, 32 patients underwent PMF fixation as well, while the remainder did not have their PMF repaired.…”