Extensor mechanism allograft in total knee arthroplasty
Female white 81 years old retired patient. She underwent total right knee arthroplasty in 2007. On the 4th postoperative day, when leaving the hospital after being discharged, she felt to the ground with trauma in the anterior knee that caused wound dehiscence and exposure of the prosthesis with loss of patellar component. The patient was again hospitalized and underwent aggressive surgical procedure for cleaning and collection of cultures and antibiotic therapy for six weeks to control a local infectious process, multi - sensitive Staphylococcus aureus having been detected. Intraoperatively, resection of 60% of the patella was required due to its fragmentation. The patient recovered well from the clinical point of view, and local infection.\nProgressively during the follow-up, she started to present pain and disability of knee extension due to lateral dislocation of the extensor mechanism to active quadriceps contraction due to the lack of restraint on the local soft parts after surgical debridement. Due to the lateralization of the extensor mechanism, she slowly progressed to medial instability and large valgus opening between 2007 and 2011. The patient did not present any evidence of loosening of the femoral and tibial components of the arthroplasty. The functional limitation became important, and surgical treatment was the option elected.\nIn October 2011 she underwent reconstruction of the extensor mechanism and the medial collateral ligament with homologous graft from a tissue bank using a complete extensor mechanism (quadriceps tendon - patella - patellar tendon - tibial tuberosity) and two flexor tendons to medial ligament complex. A channel in region of the anterior tibial tuberosity was performed to accommodate a "press fit" plug bone graft associated with 4.5- mm cortical screw with washer.\nIntraoperatively it was observed that the tibial and femoral components were fixed and well positioned and exchange was not performed.\nPatient developed an active knee extension at the immediate postoperative period. The post-operative procedures were also similar to those of cases 1 and 2.