Allogeneic Tendon Transplantation for the Treatment of Pathological Patellar Ligament Defect in Children: Technical Note and 4-Year Follow-Up.

Objective: The absence of patellar ligament will bring about a severe negative impact on daily life. Many reconstruction techniques have been described in adults. However, there is a lack of technical introduction regarding the reconstruction of the patellar ligament in children. The purpose of this study was to report a surgical technique for reconstructing the patellar ligament in children.

Method: A retrospective analysis of the clinical data on a patellar ligament (tendon sheath fibroma) patient with allogeneic tendon reconstruction. An 8-year-old child with postoperative recurrence of left patellar ligament tumor was enrolled in our study. Anterior tibialis tendon allograft was used to reconstruct the patellar ligament after complete resection of the patellar ligament for the tumor. The tunnels were constructed on the deep surface of the tibial tubercle and the root of the quadriceps tendon (to decrease the harmful impact on patella development), respectively. The allogeneic tendon was passed through the tunnels above in the shape of "8," and the two ends of the tendon were attached to the bleeding bone bed at the inferior edge of the patella with suture anchors to achieve better bone-tendon healing. During the follow-up, the knee's range of motion and imaging manifestations were recorded.

Result: Postoperative pathology suggests chondromesenchymal hamartoma, a rare benign soft tissue tumor different from the previous operation (tendon sheath fibroma). During the 4-year follow-up, the patient's active range of motion of the knee achieved 0° to 120°; and the patient could walk normally without any external help. Physical examinations (the apprehension sign and J sign) showed no ligamentous instability or patellar ligament tenderness. Imaging analysis showed that the ratio length of the patellar ligament to the patella was almost normal. The integrity, continuity, and shape of the allogeneic ligament showed excellent results in MRI. Combined with clinical and imaging findings, allogeneic tendon patellar ligament reconstruction was deemed successful.

Conclusion: Allogeneic ligament reconstruction technique can provide a treatment option by reconstructing the extensor mechanism, minimizing the impact on patellar development, and augmenting biological healing for children with the absence of the patellar ligament.