Distal insertion rupture of lateral ankle ligament as a predictor of weakened and delayed sports recovery after acute ligament repair: mid-term outcomes of 117 cases

BACKGROUND: For lateral ankle ligament rupture, surgical repair has been considered for patients requiring return to high-demanding sports. However, there is a lack of systematic research regarding arthroscopic treatment followed by ligament repair for severe acute ankle sprain. The purpose of this study was to analyze the mid-term outcomes of arthroscopy followed by open anatomic lateral ankle ligament repair surgery for acute lateral ankle sprain and the impact of ligament rupture site on the outcomes. METHODS: Professional or amateur athletes with clinically- and radiologically-confirmed grade III acute lateral ankle ligament injuries undergoing ankle arthroscopy followed by open anatomic ligament repair between June 2007 and May 2017 were reviewed. Intra-articular lesions and the location of rupture were first examined under arthroscopy. Simple suture repair was performed for mid- substance ligament rupture (middle group), while suture repair with anchors were used for the ruptures near the ligament attachment site on the fibular (proximal group), talar or the calcaneal side (distal group). Outcomes were evaluated at final follow-up, including visual analog scale (VAS) pain score, American Orthopaedic Foot & Ankle Society (AOFAS) score, Tegner score, time to return to sports, resumption of pre-injury sports level, sprain recurrence and range of motion (ROM). RESULTS: A total of 117 patients were included for analysis, with a mean follow-up duration of 46.4 ± 16.1 months. There were 48 (41%) cases in the proximal group, 41 (35%) cases in the middle group and 28 (24%) cases in the distal group respectively. At final follow-up, all of the VAS score, AOFAS score and the Tegner score were significantly improved from the pre-operative level (p < 0.001). 12 (10%) patients complained of sprain recurrence during follow-up. 14 (12%) patients reported mild ROM restriction and 7 (6%) patients experienced transient skin numbness. The average time to return to pre-injury sports was 4.34 ± 1.11 months. The smallest proportion (86% ± 13%) of resumption of pre-injury sports level was reported from the distal group, compared with 93% ± 12% for the proximal group and 89% ± 14% for the middle group (p = 0.037). Time to return to sports was significantly longer for the distal group, with an average of 4.59 ± 1.27 months compared to 3.99 ± 1.09 months for the proximal group and 4.58 ± 0.90 months for the middle group (p = 0.009). CONCLUSIONS: Ankle arthroscopy followed by open anatomic ligament repair is a reliable procedure for patients requiring return to high demanding sports after severe acute ankle sprains. Distal rupture near the talar or calcaneal end was associated with delayed return-to-sport and inferior performance in resuming pre-injury sports level.