Orthopedic Surgical Management of Complicated Congenital Popliteal Pterygium Syndrome: A Case Report.

Introduction: Popliteal pterygium syndrome (PPS) is a rare autosomal-dominant condition that causes fixed flexion deformity of the knee. The popliteal webbing and shortening of the surrounding soft tissue could limit the functionality of the affected limb unless it is surgically corrected. We reported a case of PPS in a pediatric patient encountered in our hospital.

Case: A 10-month-old boy came with a congenital abnormally flexed left knee with bilateral undescended testis and syndactyly of the left foot. The left popliteal pterygium extending from the buttock to the calcaneus was observed, with an associated fixed flexion contracture of the knee and equine position of the ankle. Normal vascular anatomy was seen in the angiographic CT scan; therefore, multiple Z-plasty and fibrotic band excision were performed. The sciatic trunk was exposed on the popliteal level, and the fascicular segment was excised from the distal stump and sutured to the proximal stump under the microscope to extend the sciatic nerve for approximately 7 cm. No postoperative complications were reported. Multiple tendons and soft tissue reconstruction were performed when the patient was 2-year-old to correct the adductus and equine deformity of the left foot.

Discussion: Surgical correction for popliteal pterygium demands staged techniques to deal with the shortened structure. In our case, multiple Z-plasty were performed, and the fibrotic band was excised until its base with meticulous consideration of the underlying neurovascular bundle. Fascicular shifting technique for sciatic nerve lengthening can be considered in unilateral popliteal pterygium with difficulty extending the knee due to shortened sciatic nerve. The unfavorable outcome of nerve conduction disturbance resulting from the procedure may be multifactorial. Still, the existing foot deformity, including a certain degree of pes equinovarus could be treated by multiple soft tissue reconstructions and adequate rehabilitation to achieve the desired outcome.

Conclusion: Multiple soft tissue procedures resulted in acceptable functional outcomes. However, the nerve grafting procedure is still a challenging task. Further study is required to explore the technique in optimizing the nerve grafting procedure for popliteal pterygium.