MRI features most often associated with surgically proven tears of the spring ligament complex

The authors aim to present the common MRI appearances of surgically proven spring ligament tears as minimal radiological literature exists regarding injury to this increasingly important structure.

Our retrospective review identified a treatment group comprising 13 cases of surgically proven spring ligament injury and a 96-patient comparison group. All patients underwent standard musculoskeletal MRI sequences of the foot and ankle. Images were reviewed by a registrar-grade orthopedic surgeon and a consultant musculoskeletal radiologist for abnormalities of the spring ligament complex.

MRI findings in relation to surgically proven injury of the superior-medial portion of the spring ligament included proximal thickening >5 mm in 92 % and distal thinning <2 mm in 85 % of proven injures to the spring ligament complex. Common abnormalities of the medio-plantar portion comprised ligament thickening >7 mm in 31 % and intra-substance signal heterogenicity demonstrated in 38 % of cases.

The complex orientation of the medio-plantar ligament makes its evaluation unreliable due to the difficulty obtaining diagnostic quality imaging and our inability to correlate MRI findings in this portion of the ligament with surgically proven injury. However, MRI abnormalities of the superior-medial ligament are consistent, reproducible, and correlate with surgical pathology. As our incomplete understanding of the flexible flatfoot deformity evolves, our ability to recognize injury to the spring ligament may encourage novel surgical treatments looking to incorporate its repair or reconstruction into deformity correction.