Accuracy evaluation of a two-wire technique for osteotomy positioning in the tibial plateau levelling procedure

Objective: To evaluate a tibial plateau levelling osteotomy (TPLO) saw blade positioning technique and to retrospectively evaluate the accuracy of the osteotomy position. Method: Preoperative and postoperative radiographs of 72 cases that had a TPLO surgery using a two-wire technique were reviewed. Three measurements (A1, B1, C1) were obtained in preoperative planning using a computer template system (Orthoview Vet) which mapped the intended osteotomy position. The postoperative radiographs were analysed to determine the variability of these three measurements (A2, B2, C2) and therefore the accuracy of the osteotomy. Results: On average the least variable measurement was B2 (5%) followed by C2 (7%) and then A2 (13%). The maximum mean difference between the intended position and achieved position was 1.5 mm. Clinical significance: Despite there being a significant difference between the intended and the actual position of the osteotomy, the variation between the intended and actual tibial tuberosity width was small (5%). None of the cases suffered a tibial tuberosity fracture, which also supports the clinical value of this technique. Care must be taken to avoid inadvertent cutting of the Kirschner guide wires.