Reconstruction of extensor mechanism after trauma and infection by transposition of the Achilles tendon: report of technique and four cases.

High-energy injuries to the knee often involve extensive soft tissue loss as well as fractures. In certain situations, the patellar tendon may be lost due to initial injury or post-injury complications such as infection. Use of the gastrocnemius flap is a popular method of covering the defect as well as controlling infection and promoting healing by increasing local vascularity. We present a method of reconstructing the patellar tendon by extending the use of the gastrocnemius flaps using its Achilles tendon and calcaneal insertion. The distal insertion of the Achilles tendon is fixed to the tibial tuberosity with a cancellous screw, and the proximal end is sutured to the quadriceps muscles. The knee is immobilized for 1 week, after which the knee is mobilized in a hinged brace. Three of the four cases had good results, one a moderate result (the initial injury was extensive, with dislocation of the knee).