Rupture of the cranial cruciate ligament (CCL) causes cranial tibial subluxation (drawer movement) and is the most common cause of hind limb lameness and stifle osteoarthritis in dogs. The current gold standard for treatment is the tibial plateau leveling osteotomy (TPLO). The goal of the TPLO is to create a biomechanically stable stifle by ‘leveling’ the tibial plateau. This is accomplished with a radial (semicircular) proximal tibial osteotomy and proximal segment rotation, resulting in a tibial plateau angle that neutralizes cranial tibial subluxation/thrust during weight-bearing. Inaccurate osteotomies result in translation of the center of rotation, thereby under- or over-correcting the tibial plateau, resulting in either incomplete elimination of tibial thrust or increased strain on the caudal cruciate ligament. Proficiency in performing the TPLO procedure free-hand is often not present until the surgeon has performed hundreds of TPLOs. Atypical anatomy such as extremely small or large animals, prior trauma, or excessive tibial plateau angles can further complicate appropriate osteotomy positioning. Thus, there is a need for an easily applied, universal saw guide to aid in creating a precise tibial osteotomy.

Our objective is to determine if a novel, 3D-printed TPLO saw guide can consistently produce accurate tibial osteotomies regardless of surgeon experience and patient size. A secondary objective is to determine if this guide can reduce surgical time because the surgeon spends less time adjusting and readjusting saw positioning. Our hypothesis is that there will be increased osteotomy accuracy and decreased intra-operative osteotomy planning time when comparing the use of the guide to the standard of care ‘free-hand’ osteotomy.

Our specific aims are 1) to develop a universal, easily applied cutting guide for the TPLO saws, 2) validate the accuracy and utility of the guides using a randomized cadaver model, and 3) assess osteotomy accuracy in a prospective, randomized clinical trial. For Aim 1, we will use computer-aided design and 3D printing to engineer specific guides customized to accommodate various TPLO saw blade sizes. Aim 2 will be accomplished using canine cadaveric hindlimbs (n=40) randomized to TPLOs with and without the use of the 3D printed saw guide. Procedures will be performed by four surgical residents on paired pelvic limbs. Pre- and post-operative stifle radiographs will be used to determine osteotomy accuracy with and without the saw guide. If Aim 2 testing reveals promising results on cadavers, the study will continue into Aim 3 as a randomized, prospective clinical study utilizing client-owned canines for testing and determination of accuracy in vivo as well as the potential for reducing time in the operating room. The specific outcome measures will include 1) degree of eccentricity of the osteotomy, 2) the resultant under- or over-correction of the tibial plateau angle, and 3) time for planning and completion of the cis-cortex osteotomy. Our goal for this project is to invent and validate an easily useable and universal TPLO osteotomy guide that can be provided open-source to other surgeons.