Rigid equinovarus deformity corrected with a multiplanar external fixator.

Abstract

Over the years, I have found treating patients with rigid equinovarus deformities to be quite a challenge.” “ R igid equinovarus deformities are uncommon, yet when they present, they can be challenging for the foot and ankle surgeon to treat. Often, these deformities occur because of the lack of posttraumatic immobilization or orthosis following head trauma, cerebral vascular accident, or neurologic injury. Patients involved in highlevel traumas can have life-threatening injuries, and initially, a neurologic condition affecting the lower extremities may be unknown. If they are fortunate to survive, patients with lower extremity deformities will have difficulty ambulating, which may be necessary for their continued longevity. Over time, the deformities can progress to a fixed position, making it difficult for nonsurgical options such as physical therapy, dynamic splinting, and serial casting to be successful. Custom bracing for rigid equinovarus deformities can be challenging and has a high rate of skin ulceration over the lateral ankle due to increased contact pressure. Surgical options for patients with fixed equinovarus deformity include Achilles tendon lengthening, medial ankle tendon release or lengthening, posterior capsule release, tendon transfer, osteotomy, and fusion. Redfern and Thordarson recently reported the results of Achilles lengthening and posterior tibial tenotomy with immediate weight bearing in patients with fixed equinovarus deformity. Nine of 10 patients had significant improvement in deformity and ambulatory status. However, rapid restoration of a neutral ankle position surgically can increase skin and neurologic complications. I have encountered wound complications and neurologic insult as a result of rapid correction to a plantigrade foot in patients with rigid equinovarus. These complications caused me to rethink how I approach this patient population. The goal of surgery is to achieve a plantigrade foot, improve ambulatory status, balance the foot and ankle, and allow weight bearing with the fixator once the ankle has become more neutral. The multiplanar external fixator allows the surgeon to correct the deformity in a controlled manner, helping to prevent skin and neurologic complications. The key preoperative decision-making elements include short-term goals, longterm goals, and assessing the need to add tendon transfers to balance the foot. The major long-term goal is for the patient to ambulate on the affected extremity. Patients who have no chance of neurologic recovery (ie, sciatic nerve injury following knee dislocation) and no muscle function may not be candidates for tendon transfer after correction of the deformity. They will benefit by having an extremity that is braceable. Patients who have some neurologic recovery and would be amendable to a tendon transfer if their deformity had not been rigid will benefit by correcting the deformity and doing the tendon transfer as a staged procedure. I believe there is merit in correcting the deformity gradually and then staging a tendon transfer, such as a bridle procedure, to help provide balance to the foot and ankle. I have treated several patients who have had previous neurologic injury to their