Recurrent Heterotopic Ossification and Varus Deformity of the Knee Following Retrograde Intramedullary Nailing of Fractured Femur

Background: Retrograde femoral nailing is an indicated procedure for femoral shaft fractures. Heterotopic ossification, tibial deformity, and fibular collateral ligament laxity are rare and not well understood complications of retrograde femoral nailing. Case Information: This case documents a 16-year-old female who suffered polytraumatic injuries following a high-speed motor vehicle accident. Following repair of left ipsilateral femoral neck and shaft fracture with sliding hip screw and retrograde femoral intramedullary nailing patient developed left knee stiffness, loss of motion, and pain. Following arthroscopy patient was found to have heterotopic ossification and arthrofibrosis. Nine months later patient was taken for third orthopedic procedure after development of left knee varus due to tibial deformity, fibular collateral ligament laxity, and recurrent heterotopic ossification. Conclusion: This case illustrates patient with recurrent development of heterotopic ossification, development of knee varus treated with high tibial open angle osteotomy, and advancement of the proximal attachment of the fibular collateral ligament with the use of intramedullary nailing locking screw hole remnants.