In vitro evaluation of a custom cutting jig and custom plate for canine tibial plateau leveling

Objective-To design and manufacture custom titanium bone plates and a custom cutting and drill guide by use of free-form fabrication methods and to compare variables and mechanical properties of 2 canine tibial plateau leveling methods with each other and with historical control values. Sample Population-10 canine tibial replicas created by rapid prototyping methods. Procedures-Application time, accuracy of correction of the tibial plateau slope (TIPS), presence and magnitude of rotational and angular deformation, and replica axial stiffness for 2 chevron wedge osteotomy (CWO) methods were assessed. One involved use of freehand CWO (FHCWO) and screw hole drilling, whereas the other used jig-guided CWO (JGCWO) and screw hole drilling. Results-Replicas used for FHCWO and JGCWO methods had similar stiffness. Although JGCWO and FHCWO did not weaken the replicas, mean axial stiffness of replicas after JGCWO was higher than after FHCWO. The JGCWO method was faster than the FHCWO method. Mean +/- SD TPS after osteotomy was lower for FHCWO (4.4 +/- 1.1 degrees) than for JGCWO (9.5 +/- 0.4 degrees), and JGCWO was more accurate (targetTPS, 8.9 degrees). Slight varus was evident after FHCWO but not after JGCWO. Mean postoperative rotation after JGCWO and FHCWO did not differ from the target value or between methods. Conclusions and Clinical Relevance-The JGCWO method was more accurate and more rapid and resulted in more stability than the FHCWO method. Use of custom drill guides could enhance the speed, accuracy, and stability of corrective osteotomies in dogs.