Abstract
Objective Rock-back is a reported complication following tibial plateau levelling osteotomy
(TPLO), whereby tibial plateau angle (TPA) increases postoperatively. The mechanism
of rock-back is not fully understood, although a recent ex vivo investigation demonstrated that osteotomy exit cut angle (ECA) and inclination of
the plate in the sagittal plane might be risk factors. The purpose of this study was
to explore these relationships in a clinical dog population. We hypothesized that
dogs with rock-back would have a higher degree of plate inclination and downward ECA
compared with those without rock-back.
Materials and Methods Medical records and radiographs of dogs that underwent TPLO between January 2021
and January 2022 were retrospectively reviewed. TPA was recorded preoperatively, postoperatively,
and at follow-up. Plate inclination, ECA, and descriptive data were collected. Observers
measuring TPA were blinded to other variables. Rock-back was defined as a change in
TPA ≥ 2.
Results Ninety-five TPLO procedures met the inclusion criteria (n = 87 dogs). Rock-back was identified in 21% of TPLOs (n = 20/95). The mean increase in TPA in the rock-back group was 3.2 ± 2.6. Plate inclination
and ECA were not correlated with the presence of rock-back. Descriptive variables
did not have a significant correlation with rock-back.
Conclusion Plate inclination and ECA did not have a relationship with rock-back when defined
as a postoperative TPA change ≥2 degrees, in this clinical retrospective study.
Keywords
TPLO - plateau angle - TPLO complications - rock-back
