The Lateral Trans-Malleolar approach for Posterior Malleolar Fracture of the Ankle: A Clinical and Computed Tomography Evaluation

Abstract

Category: Ankle; Trauma Introduction/Purpose: Posterior malleolar fracture reduction including the articular surface of trimalleolar ankle fracture has been reported to be an important prognostic factor. The lateral trans-malleolar approach (LTA) is a surgical approach that provides direct visualization of the articular surface of the posterior malleolus. We herein report the clinical results and computed tomography (CT) findings for the articular reduction status after LTA for posterior malleolar fracture of the ankle. Methods: Sixteen patients (9 men, 7 women, mean age 52.6+-18.1 years old) who underwent the LTA for posterior malleolar fracture of the ankle and were followed for at least 1 year were evaluated retrospectively. The types of ankle malleolar fracture according to the Lauge-Hansen classification were Supination-External rotation (SER) in 13 patients and Pronation-External rotation (PER) in 3 patients. The CT classifications of posterior malleolus fracture by Haraguchi were Type 1 in 6 cases, Type 2 in 10 cases and Type 3 in 0 cases. The AOFAS score, post-surgical complications and reduction status of the posterior malleolus on CT were investigated. Results: The mean follow-up period was 15.5 months. The AOFAS score was 93.0+-5.2 points. Postoperative complications were seen in one case of superficial infection; however, delayed union, nonunion and fibular necrosis were not observed. The articular step-off in CT improved significantly after surgery (5.9+-2.9 mm preoperatively vs. 0.6+-0.8 mm postoperatively). The 2 patients who showed an articular step-off exceeding 1 mm were both Haraguchi type 2 posterior malleolar fracture. Conclusion: Several approaches for managing posterior malleolus of the ankle have been reported. However, few provide direct visualization to the articular surface. The LTA requires relatively substantial invasion, but it can facilitate surgery in the supine position and thereby reduce the articular surface directly. In our experience, the LTA provided favorable clinical results and fracture reductions. Even when utilizing the LTA, it remains difficult to confirm the fracture reduction of medial articular surface for Haraguchi type 2 medial extension fractures. Therefore, it remains important to also perform appropriate intraoperative X-ray controls.