Long-term outcomes of thigh circumference, stifle range-of-motion, and lameness after unilateral tibial plateau levelling osteotomy.

Our study evaluated thigh circumference (TC), stifle range of motion (ROM), and lameness in dogs one to five years after unilateral tibial plateau levelling osteotomy (TPLO). We hypothesised that TC, stifle ROM, and lameness would not be different to the unoperated limb (control), one to five years after surgery. Patients that were one to five years post-TPLO were reviewed and were included if they had a unilateral TPLO, and no additional clinical evidence of orthopaedic disease. Standing mid-thigh TC measurements and stifle extension and flexion angles were made in triplicate. Clinical lameness was graded blindly. Data were evaluated statistically using paired t-tests for TC and stifle flexion and extension. Significance was set at p <0.05. Twenty-nine dogs met the inclusion criteria. Mean results for the surgery limbs and control limbs were 39.5 +/- 5.5 cm and 40.1 +/- 5.6 cm for TC, 36.6 +/- 6.8 degrees and 28.6 +/- 4.3 degrees for stifle flexion, and 155.2 +/- 6.6 degrees and 159.8 +/- 4.9 degrees for stifle extension, respectively. The mean TC for the operated limb was 98.5% of the control limb. A significant difference was found between the operated and the control limbs for all measurements. Time after surgery had no apparent affect on outcome. Four of 29 dogs (14%) exhibited some lameness in the TLPO limb during evaluation (one dog was 1 to 2 years postoperative and three dogs were 2 to 3 years postoperative). These results indicate that TC and stifle ROM in the TLPO limb do not return to control-limb measurements one to five years after a TPLO surgery. The clinical significance is unknown as TC returned to 98.5% of control, and the source of lameness in the lame dogs was not identified.