Lateral Joint Distraction Through Distal Fibula Lengthening Osteotomy for Lateral Compartment Ankle Osteoarthritis

CATEGORY: Ankle; Trauma INTRODUCTION/PURPOSE: Lateral compartment ankle OA, commonly due to trauma such as ankle fracture, is not very rare. However there's no definite established surgical treatment option. In this study, we suggest distal fibula lengthening osteotomy for lateral joint distraction as one of treatment surgical option. We have experienced favorable clinical outcome for 3 cases of post- traumatic lateral compartment ankle OA with joint space narrowing treated with distal fibula distraction osteotomy. We report the case series with the surgical technique and the clinical-radiological outcome. METHODS: From April 2016 to August 2021, three ankles which underwent distal fibula distraction osteotomy were included in this study. All three ankles had a history of OR/IF due to fractures in the ankle joint and were diagnosed with lateral compartment OA. We defined lateral compartment OA when clinical symptoms and radiologic findings were consistent. Clinically, the point of pain was characterized as the lateral compartment of the ankle joint, not the syndesmosis or peri fibular area. Radiologically, joint space narrowing is showed in X-ray, and CT arthrography or MRI confirmed cartilage denudation of the lateral compartment. RESULTS: 1) Clinical outcomes (Table 1) Case 1: The AOFAS score improved from 69 preoperatively to 93 postoperatively, and the Pain vas score improved from 7 to 0. According to patient's subjective expression, daily activity became 'Boxing available' from 'Hard to run'. Case 2: The AOFAS score improved from 73 preoperatively to 91 postoperatively, and the Pain vas score improved from 5 to 0. According to patient's subjective expression, daily activity became 'No pain on daily activity' from 'Hard to walk'. Case 3 is not described because there has been no progress for more than 1 year after surgery. 2) Radiologic outcomes (Table 2) Lateral joint space, talocrural angle, talar tilt angle and tibia axis-talar dome angle were all changed close to the contralateral ankle index after surgery. CONCLUSION: Painful ankle OA localized to the lateral compartment in young age is uncommon and there is no definite surgical method. Distal fibula distraction osteotomy is reasonable surgical method that does not burden patients and surgeon. In our study, distal fibula distraction osteotomy showed favorable clinical-radiological outcomes. So, we recommend this method for painful lateral compartment OA in young ages.