We report a case of chronic patellar tendon rupture in a 49 years old female patient who has been suffering from rheumatoid arthritis for over 20 years and was on a long-term therapy with corticosteroids and methotrexate. She came to our hospital complaining of her inability to extend the right knee which started suddenly a year and a half ago without any history of trauma. The reason behind the delayed presentation is that she had been managed in another hospital using different kinds of orthotics. Clinical examination showed a high riding patella along with a gap in the patellar tendon area. A magnetic resonance imaging (MRI) was done and it showed a complete rupture of the patellar tendon (Fig. 1).
After seven months from the patient's presentation to our hospital, she underwent reconstruction of the patellar tendon using a massive BTB allograft. Prophylactic antibiotics were administered prior to surgery and the patient was put under general anesthesia with an appropriate dose of muscle relaxant. While the patient was in a supine position with a tourniquet applied and a bump placed beneath the ipsilateral thigh, a midline longitudinal incision extending beyond the superior pole of the patella and distal to the tibial tuberosity was made. The soft tissue was released to bring the retracted patella distally. The large bone block of the BTB allograft was fixed to the patella with two K-wires and a tension band in a similar technique to that used in the fixation of patellar fractures. After performing a tibial osteotomy to contain the distal bone block, the allograft was anchored to the tibia, more distal than usual, using two screws. The purpose of the distal placement was to utilize the graft which had a greater than ideal length while maintaining an optimal tension of the knee extensor mechanism. After closure, two views of plain radiographs were taken (Fig. 2). Early range of motion was allowed through a flexion-extension knee orthotic. Passive full extension and 30  of flexion were permitted. Partial weight bearing and active extension began three weeks after surgery. No complications were observed in the postoperative period. However, the two screws over the tibial tuberosity were removed after one year because of their prominence and x-ray images were taken afterwards showing an adequate union (Fig. 3).
Three years after surgery, the patient had active and passive range of motion between -20 and 120  and was walking normally without any external support (Fig. 4, Fig. 5).