Flatfoot Deformity Due to Isolated Spring Ligament Injury

Patients with acquired flatfoot deformity due to isolated injury of the spring ligament, with healthy posterior tibialis tendon, are rarely identified. Between December 2004 and September 2011 (6 years and 9 months), we treated 10 patients with acquired flatfoot deformity due to spring ligament injury without tibialis posterior tendon tear. One patient (10%) was lost to follow-up. The mean age of the patients was 44.33 ± 12.91 years; 4 (44.4%) were female, and 5 (55.56%) were male. Clinical presentation included mild to moderate hindfoot valgus and pain extending from the inferior part of the medial malleolus to the navicular, inferior to tibialis posterior. Forefoot abduction was not always present. Weightbearing radiographs and magnetic resonance imaging (MRI) scans were obtained in all cases. Six patients (66.66%) of the patients had a history of minor trauma. Spring ligament repair was performed in all cases, and 4 patients (44.44%) underwent adjunct procedures. After surgery, a cast was applied, and weightbearing was avoided for 6 weeks. The mean preoperative American Orthopaedic Foot and Ankle Society (AOFAS) score was 39.66 ± 18.55, and this improved to 84.88 ± 12.41 after surgery (p = .023). No statistically significant differences were found between males and females or between isolated repairs and adjunct procedures. The mean duration of follow-up was 45.33 ± 37.11 months (range 15 to 120), and no complications were identified. Isolated injuries of the spring ligament with normal posterior tibialis tendon are rarely described and may be more prevalent than generally appreciated.