Reconstruction of the Quadriceps Extensor Mechanism with a Calcaneal Tendon-Bone Allograft in a Dog with a Resorbed Tibial Tuberosity Fracture.

A non-reducible tibial tuberosity fracture is a rare complication of tibial tuberosity transposition performed during correcting of medial patella luxation (MPL) in dogs. This condition severely disrupts the quadriceps extensor mechanism, leading to significant pelvic limb lameness. An 11-year-old, 1.8 kg spayed female Yorkshire Terrier sustained a comminuted left tibial tuberosity fracture during surgical correction of an MPL. Six months after surgery, the dog was markedly lame and unable to extend the left stifle. Radiographs revealed patella alta and resorption of the fragmented tibial tuberosity. A composite frozen allogeneic calcaneal tendon-bone block was utilized to reconstruct the tibial tuberosity and reattach the patellar ligament. Initial postoperative radiographs confirmed restoration of a normal patellar ligament to patella length ratio (1.42). Both the allogeneic bone used for tibial tuberosity reconstruction and the tendon used to reattach the patellar ligament were successfully integrated. The dog regained satisfactory limb function without recurrence of patella luxation, as reported by the owners 29 months postoperatively. The use of a calcaneal tendon-bone allograft effectively restored the functional integrity of the quadriceps extensor mechanism, providing a viable option for addressing quadriceps insufficiency resulting from the loss of the osseous tibial insertion.