Impacts of tibial plateau levelling osteotomy on the tibial insertion of the medial collateral ligament of the canine stifle joint - A cadaveric study.

OBJECTIVE

The aim of this study was to assess the potential consequences of tibial plateau levelling osteotomy (TPLO) for the medial collateral ligament (MCL) tibial insertion (TI) with a particular focus on the effects of the TPLO planning technique and of the size of saw blade.

STUDY

DESIGN

Eighty-six stifle joints were collected from 43 canine cadavers and dissected free of soft tissue to expose the MCL. The MCL insertion sites were first identified with Chinese ink on intact stifle joints, and then marked with radio-opaque barium sulfate after removal of the MCL. Mediolateral radiographs were made of each marked stifle joint and used for TPLO digital planning. For each stifle, planning the TPLO was performed by centring the osteotomy at the intersection of the tibial plateau and the mechanical axis of the tibia in group 1, and at the top of the intercondylar tubercles in group 2. Whenever possible, two saw blade sizes were tested in each group. Measurements were taken after TPLO simulation to assess how the procedure would alter the MCL TI.

RESULTS

In group 1, the integrity of the MCL TI was affected by the TPLO planning in 87.2% of the cases with the small saw blade and in 59.3% of the cases with the large blade, and in group 2, in 94.2% of the cases with the small and 77.9% with the large saw blade. In group 1, the osteotomy line was located above the TI, completely severing the MCL in four cases versus in 11 cases in group 2, while severing occurred in 14/15 cases with the small saw blade.

CONCLUSION

During TPLO, the osteotomy line transected the MCL TI in the majority of dogs. Centring the osteotomy at the intersection of the tibial plateau and the mechanical axis of the tibia and using the largest saw size that preserves tibial tuberosity and patellar tendon insertion seems to be the best way to preserve the MCL TI as much as possible. Further research is needed to evaluate the clinical impact of MCL TI transection.