Modified Tibial Plateau Levelling Osteotomy in a Cat With a Cranial Cruciate Ligament Rupture and a Concurrent Medial...

A 12-year-old, castrated male Russian Blue cat presented with chronic right pelvic limb lameness that had markedly worsened over the previous week. Orthopaedic examination revealed cranial cruciate ligament rupture with concurrent Grade 3 medial patellar luxation (MPL) in the right stifle. Pain was elicited upon patellar reduction. Radiographs showed a tibial plateau angle (TPA) of 35° and medial deviation of the tibial tuberosity. A modified tibial plateau levelling osteotomy (mTPLO) was planned for the right pelvic limb to correct both cranial tibial thrust and MPL in a single procedure. The right stifle was explored by lateral arthrotomy, and adjunctive surgical techniques, including trochlear block recession, medial release and lateral imbrication, were performed to correct the MPL. The proximal tibial segment was rotated to achieve a post-operative TPA of 5° and stabilized using an Arix-vet 1.5/2.0 mTPLO plate with a 2-mm offset. Post-operative imaging confirmed correction of the TPA and lateral translation of the tibial tuberosity. The bone apposition ratio was 0.83. At 4 months post-operatively, radiographic union was confirmed. Gait pattern and orthopaedic examination findings, including patellar stability and absence of cranial tibial thrust, were comparable to the pre-deterioration clinical state.

To our knowledge, this is the first report of mTPLO in a feline patient. Given the difficulty of post-operative exercise restriction in cats, the single-cut design and maintenance of bone apposition of the mTPLO may offer enhanced stability. No significant alteration in the mechanical medial proximal tibial angle was observed, supporting the safety of a 2-mm offset in this case.