Objective To observe the efficacy of tendon allograft reconstruction of chronic lateral ankle instability (CLAI).Methods We retrospectively reviewed the 30 CLAI patients who had received tendon allograft reconstruction of lateral ligament between January 2013 and January 2014.They were 12 men and 18 women,aged from 23 to 45 years (average,35.3 years).Their American Orthopaedic Foot and Ankle Society (AOFAS) ankle and hindfoot score,Karlsson-Peterson score,Sefton articular stability scale,anterior talar translation and talar tilt angle were compared between preoperation and the last follow-up.Results Of this series,26 cases (26 ankles) were followed up for an average period of 20.3 months (from 15 to 27 months).Follow-up at 6 weeks after surgery showed they could complete non-weight-bearing walking and follow-up at 12 weeks observed that they achieved weight-bearing walking.X-ray films showed negative results of stress ankle varus test and anterior drawer test.At the last follow-up,all patients recovered normal life without obvious discomfort.Their AOFAS ankle and hindfoot score (87.1 ± 4.9),Karlsson-Peterson score (89.6 ± 4.5),Sefton articular stability scale (grade Ⅱ),anterior talar translation (3.5 ± 0.4 mm) and talar tilt angle (3.9 ° ± O.9°) at the last follow-up were significantly improved in comparison with the preoperative values (56.3 ± 11.0,51.1 ±7.5,grade Ⅳ,7.6 ±0.8 mm,14.3°±2.2°,respectively) (P ＜ 0.05).The follow-up showed 15 excellent,6 good and 5 poor ankles,yielding a patient satisfaction rate of 80.8％.Conclusions Anatomic reconstruction with tendon allograft is safe and effective for chronic lateral ankle instability.

Based on the method of the numerical integral,a program for capacity of L-shape column is designed,and validated.It is analyzed that M_x-M_y curves of inequiaxial L-shape column with different optimization forms of reinforcements.It is proposed stressed steel bar should be at end and corner;the constructional reinforcement at other locations.Increasing reinforcement is helpful to improve engineering axial direction forces.