Retrospective analysis of modified Karlsson surgery for chronic calcaneofibular ligament injury

Objective To retrospectively evaluate the therapeutic effect and influencing factors of the modified Karlsson operation (anchor method) in treating chronic rupture of the calcaneofibular ligament (CFL). Methods From August 2010 to May 2014, the data of 24 patients with calcaneofibular ligament rupture treated in Institute of Sports Medicine, Third Hospital of Peking University were retrospectively analyzed. All cases were repaired with modified Karlsson operation (anchor method). There were 14 males and 10 females, with an average age of (30±9) years, and the average body mass index (BMI) was (25±5) kg/m2. Visual analogue pain score (VAS), American Foot and Ankle Surgery Association score (AOFAS), Tegner knee motion score, ankle stability and mobility were followed up and analyzed. The paired t test was used to compare the normal distribution data before and after the operation. Results The average follow-up time was (41±13) months. Compared with pre-operation, VAS score decreased significantly at the last follow-up [0(0,7) vs 5(0,8), Z=4.13,P=0.000], AOFAS score increased significantly (94±10 vs 70±14, t=8.94, P<0.05), Tegner score increased significantly (4.7±1.5 vs 2.8±1.3, t=6.87, P<0.05), all improved significantly. AOFAS score was excellent in 19 cases, good in 4 cases and moderate in 1 case, the excellent and good rate was 95.8%. Among them, 20 cases (83.3%) were satisfied with the recovery effect after the operation. Postoperative sprain occurred in 5 cases (20.8%) and ankle mobility was limited in 3 cases (12.5%). Conclusions The modified Karlsson operation (anchor method) can restore the stability of the ankle joint by treating the chronic rupture of CFL. It is an effective therapy for lateral ankle instability. Key words: Calcaneofibular ligament rupture; Modified Karlsson surgery; Chronic ankle instability