Magnetic Resonance Imaging Findings of the Lateral Ankle Instability after Anatomical Ligament Reconstruction Using a Semitendinosus Allograft Tendon with Biotenodesis Screws

Category: Ankle Introduction/Purpose: Surgery for lateral ankle instability is indicated in patients who have repetitive inversion ankle sprains despite conservative therapy. There have been many reconstruction procedures performed for the lateral ankle ligament instability. However, there has not been any report of postoperative MRI findings of lateral ankle instability after ligament reconstruction using a free tendon and biotenodesis screws. Therefore, this study was to analysis the MRI finding of the postoperative lateral ankle reconstruction using semitendinosus allograft tendon and the correlation with clinical outcome. Methods: The study is based on 34 ankles (33 patients) of chronic lateral ankle instability which underwent anatomical lateral ankle ligament reconstruction using a semitendinosus allograft tendon with bio-tendosis screws from July 2009 to April 2017 with at least 6 month postoperative ankle MRI checked (mean follow-up 16.5mo). In addition, clinical outcomes were evaluated using VAS pain score, American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, Karlsson-Peterson score, ankle stress views and subjective patient satisfaction. Results: Six ankles (17.6%) showed normal signal intensity(SI) while 28 ankles (82.4%) showed high SI on reconstructed allograft tendon area. High signal was shown around the biotenodesis screws. Eleven ankles showed synovitis (39.3%), partial tear of reconstructed allograft tendon 6 ankles (21.4), 5 osteolysis of the bone tunnel (17.9%), 4 screw pulled-outs (14.3%), 2 tendon complete tear (7.1%), 2 mucoid changes (7.1%), 2 cystic changes (7.1%). One ankle showed post-op MRI findings of reconstructed tendon infection (3.6%). The mean VAS pain score significantly decreased from 5.7 to 1.5. The mean AOFAS score improved from 72.0 to 89.1, while the Karlsson-Peterson score significantly improved from 54.7 to 85.7 (p<0.01) with 88% patient satisfaction. Stress talar tilt angle improved from 15.7o to 5.4 o. Conclusion: In the current study, various postoperative MRI findings were found after lateral ankle ligament reconstruction using allograft tendon and biotenodesis screws including high signal change of tendon, synovitis, tunnel osteolysis, screw pull-outs, tendon tears and etc. However, these MRI findings did not present as clinical complications and did not correlate with poor clinical outcomes.