Computed tomographic assessment of plate offset in modified tibial plateau levelling osteotomy with a precontoured plate with an anatomical design for treatment of cranial cruciate ligament rupture and medial patellar luxation in small-breed dogs: An in vitro study.

AIM: To evaluate the effect of plate offset using a PCM-TPLO plate with an anatomical design for medial translation of the proximal tibial segment and frontal-plane alignment during modified TPLO in small-breed canine tibial models using CT.

METHODS

Five distinct small-breed tibial morphologies were reproduced as three-dimensional-printed bone models and assigned to three plate offset conditions (0, +2 and +4 mm; total n = 15). A jig-assisted TPLO technique was performed by a single surgeon. CT-based measurements included MED, preoperative and postoperative mMPTA, TPA and APP.

RESULTS

The MED increased with plate offset (-0.11 ± 0.43 mm, 1.45 ± 0.42 mm and 3.07 ± 0.41 mm at 0, +2 and +4 mm, respectively), showing a strong linear association with nominal offset (R2 = 0.92, P < 0.0001). The mMPTA increased with larger plate offsets, whereas APP decreased but remained above the 0.5 threshold for mechanical stability. The TPA was consistently restored to the intended postoperative target (approximately 5°) in all groups.

CONCLUSIONS

PCM-TPLO plates enabled predictable medialisation in small-breed tibial models. The CT-based analysis provided precise quantification and confirmed that translation occurred in reproducible increments despite geometric limitations. These findings support the clinical applicability of PCM-TPLO plates for combined stifle stabilisation and extensor mechanism realignment while emphasising the influence of implant geometry and tibial morphology on surgical outcomes.