Assessing the Effectiveness of Modified Tibial Plateau Leveling Osteotomy Plates for Treating Cranial Cruciate Ligament Rupture and Medial Patellar Luxation in Small-Breed Dogs

Simple Summary In small-breed dogs, medial patellar luxation and cranial cruciate ligament rupture often occur concurrently in the adult dog, presenting through diverse mechanisms. Numerous methods have been developed to treat these conditions together. The combined osteotomy method may elevate the risk of joint instability and fractures. Therefore, a pre-contoured modified tibial plateau leveling osteotomy plate was designed to achieve the dual effect of tibial tuberosity transposition, a surgery performed in kneecap dislocation correction, alongside reducing the tibial plateau angle. In this cadaveric study, we examined the efficacy and stability of this modified plate. The findings indicate that this pre-contoured plate effectively prevents forward displacement of the tibia (shinbone) and medial (inner) dislocation of the kneecap while maintaining stability.Abstract In small-breed dogs with concurrent cranial cruciate ligament rupture (CCLR) and medial patellar luxation (MPL), correcting both disorders is are essential for restoring normal gait. However, the previously described surgical treatment, using two osteotomy technique, poses a high risk of fracture and instability. Addressing CCLR and MPL with a single osteotomy and implant was considered superior to the conventional method. Therefore, a pre-contoured modified tibial plateau leveling osteotomy (PCM-TPLO) plate facilitating medial shifting of the proximal tibia was developed. We compared postoperative alignment and strength between this novel plate group and a conventional tibial plateau leveling osteotomy (TPLO) plate group using eight small-breed dog cadavers each. Additionally, we investigated the potential of the novel plate as an alternative to tibial tuberosity transposition. Postoperative alignment and strength were assessed through radiographs and mechanical testing. Measurements including tibial plateau angle, mechanical medial proximal tibial angle, and number of screws within the joint were also analyzed. There were no significant differences in all measured parameters. For the novel plate, the medial displacement ratio of the proximal tibia was confirmed to be approximately 30%, and the result was thought to be appropriate. These findings suggest that the PCM-TPLO plate could be a promising alternative for treating concurrent CCLR and MPL in small-breed dogs.