SLR - August 2013 - Angela Riznyk
Reference: Orr JD, Nunley JA. Isolated spring ligament failure as a cause of adult-acquired flatfoot deformity. Foot Ankle Int. 2013; 34(6): 818-823.
Scientific Literature Review
Reviewed by: Angela Riznyk, DPM
Residency Program: Inova Fairfax Hospital
Podiatric Relevance: Adult-acquired flatfoot is a significant pathology seen by all foot and ankle surgeons. This condition can be flexible or rigid, and it is most commonly caused by dysfunction of the posterior tibial tendon. There are other causes of this condition including isolated failure of the plantar calcaneonavicular or spring ligament. The spring ligament maintains the medial arch by acting as a fibrocartilagenous sling that supports the head of the talus. It has been reported in the literature that the spring ligament is damaged along with the posterior tibial tendon in 82-92 percent of patients with flexible pes planovalgus. Isolated rupture has been previously described in the literature in adults as well as in the pediatric population and has been treated nonoperatively as well as surgically. While isolated rupture of this ligament is rare, misdiagnosis can lead to inappropriate management.
Methods: This study was a retrospective case series of six patients, all female with a mean age of 42 years, which were managed surgically for unilateral flexible adult-acquired flatfoot from 2003 to 2010. These patients had medial foot pain for a mean of 27 months prior to seeking treatment. Patients were initially managed conservatively and five of six patients underwent MRI prior to surgery. Intraoperatively, all patients were found to have a ruptured spring ligament but a normal tibialis posterior tendon upon direct visualization. All patients underwent direct primary spring ligament repair with or without adjunctive flatfoot corrective procedures including medial calcaneal slide osteotomy, lateral column lengthening, and/or medial cuneiform plantarflexion osteotomy, at the discretion of the primary surgeon.
Results: Preoperatively, five of six patients had an MRI where a rupture of the spring ligament was suspected. Three of these patients also were suspected to have posterior tibial tendinopathy based on MRI results. Upon intraoperative inspection, all six patients had a normal tibialis posterior tendon with isolated rupture of the spring ligament. The superomedial portion of the ligament was most often damaged. One patient underwent only spring ligament repair while the other five patients underwent spring ligament repair with adjunctive flatfoot procedures. At a mean follow-up of 13 months, five patients were completely satisfied. These patients reported no pain and no need for the use of orthotics. One patient who underwent a medial cuneiform plantarflexion osteotomy and lateral column lengthening, in addition to her spring ligament repair, had residual pain and continued orthotic use at six months post-op due to delayed union of the lateral column lengthening allograft. There were no other complications and no recurrence of the deformity in all six patients.
Conclusions: While this study was a small, retrospective series, the authors presented a condition that seems to be under-reported in the literature. Most spring ligament injuries are seen with concomitant damage to the posterior tibial tendon. From this study, physicians should be aware that isolated ruptures of the spring ligament do exist and may be the cause of continued medial arch pain in the absence of posterior tibial tendon dysfunction. In patients undergoing operative management for adult-acquired flatfoot, the spring ligament should be explored and repaired, if necessary, to avoid recurrence of the condition and continued pain.