When A Posterior Tibial Tendon Rupture Is Combined With A Spring Ligament Injury
The posterior tibial tendon is a frequently injured tendon in the foot and the rupture of this tendon has received increased attention in the literature since Key first described it in 1953.1 Failure of the posterior tibial tendon results in adult-acquired flatfoot deformity. The medial longitudinal arch’s mechanical integrity relies on the dynamic support of muscles, the static support of ligaments and joint capsules, and the behavior in which the tarsal bones interlock.2
The chief dynamic stabilizer of the hindfoot is the posterior tibial muscle-tendon unit. After rupture of the posterior tibial tendon, the ligaments and joint capsules appear to tear, stretch or rupture under amplified stress.2 With ensuing adult-acquired flatfoot deformity, one will note valgus alignment of the calcaneus, plantarflexion of the talus, abduction of the forefoot and pronation of the foot.2 The static structures of the arch of the foot may offer the most support, especially during stance, regardless of the posterior tibial tendon’s vital role.
The spring ligament, which physicians also refer to as the calcaneonavicular ligament, extends from the sustentaculum talus to the navicular tuberosity and supports the plantar medial aspect of the talar head. The spring ligament is made up of the superomedial and inferior calcaneonavicular ligaments. The superomedial component lies medial to the talar head and blends with the deltoid ligament, which frequently has attenuation or gross tears in patients with adult-acquired flatfoot.2,3
Authors have reported the connection between tear of the posterior tibial tendon and injury to the spring ligament. Patients with more severe abnormalities of the hindfoot may have injuries to both the tibial tendon and the spring ligament. Gazdag and Cracchiolo have promoted the idea that one should also inspect the spring ligament in patients with posterior tibial tendon pathology.2 Gazdag and Cracchiolo note if surgeons find a damaged spring ligament, they must repair it during surgery for the posterior tibial tendon insufficiency.
Yao and colleagues depicted the appearance of spring ligament insufficiency on magnetic resonance imaging (MRI) and also noted its association with posterior tibial tendon tears.4 When examining patients with a surgically verified spring ligament tear, Yao and co-workers found the superomedial portion of the spring ligament to be thickened with a heterogenous signal as it coursed along the medial aspect of the talar head.
Balen and Helms found abnormality of the spring ligament to have a high association with advanced posterior tibial tendon injury.5 On MRI, they found the spring ligament to be abnormal in 23 of 25 patients with a posterior tibial tendon injury.
A Look At The Classification System Based On Surgical Intervention
At the University Foot and Ankle Institute, we categorize spring ligament injuries into three classes and determine an appropriate treatment course accordingly.
The first category consists of a spring ligament that may have mild fraying or weakening without a gross tear and no talar head protrusion. In such cases, a surgical repair is not usually necessary and the main treatment is arch support through bracing or orthotics. At our institute, we have also used platelet rich plasma injections to augment the healing process in chronic cases of stage one spring ligament disorder.