Geometric analysis evaluating the effect of tibial plateau leveling osteotomy position on postoperative tibial plateau slope^[*]

Summary

The tibial plateau leveling osteotomy procedure is designed to neutralize cranial tibial thrust by precisely reducing tibial plateau slope. Despite accurate intraoperative measurement and proximal tibial plateau segment rotation, postoperative assessment of tibial plateau slope frequently reveals a measured angle differing from the expected postoperative angle of 5.0 degrees. The effect of osteotomy placement on postoperative tibial plateau slope was evaluated by analysing its effect on the points utilized in tibial plateau slope measurement. Four osteotomy placements, encompassing the point dividing the intercondylar tubercles and an osteotomy centred on this point, were evaluated. The effect of centreing the osteotomy distal to the intercondylar tubercles was more closely evaluated. Formulae to determine the distance the intercondylar tubercles move, the angular shift of the tibial long axis after proximal tibial plateau segment rotation, and the relation of the final and intended tibial plateau slope were derived. Osteotomy placement centred on the proximal tibial long axis point results in a lack of movement or angular shift of the tibial long axis, after proximal tibial plateau segment rotation. Other osteotomy placements result in movement of the intercondylar tubercles, tibial long axis shift, and deviation from the expected postoperative tibial plateau slope. Centreing the tibial plateau leveling osteotomy on the proximal tibial long axis point is the mathematically correct position.

Keywords

Tibial - plateau - leveling - osteotomy - position

^* Presented in abstract form at the 29th Annual Conference of the Veterinary Orthopedic Society, Park City, Utah, USA

• References

• 1 Arnoczky SP, Torzilli PA, Marshall JL. Biomechanical evaluation of anterior cruciate ligament repair in the dog. An analysis of the instant centre of motion. J Am Anim Hosp Assoc 1977; 13: 533-8.
• 2 Caylor KB, Zumpano CA, Evans LM, Moore RW. Intraand interobserver measurement variability of tibial plateau slope from lateral radiographs in dogs. J Am Anim Hosp Assoc 2001; 37: 263-8.
• 3 Li G, Rudy TW, Allen C, Sakane M, Woo SL. Effect of combined axial compressive and anterior tibial loads on in situ forces in the anterior cruciate ligament: A porcine study. J Orthop Res 1998; 16: 122-7.
• 4 Morris E, Lipowitz AJ. Comparison of tibial plateau angles in dogs with and without cranial cruciate ligament injuries. J Am Vet Med Assoc 2001; 218: 363-6.
• 5 Reif U, Hulse DA, Hauptman JG. Effect of tibial plateau leveling on stability of the canine cranial cruciate-deficient stifle joint: An in vitro study. Vet Surg 2002; 31: 147-54.
• 6 Slocum B, Devine T. Cranial tibial thrust: A primary force in the canine stifle. J Am Vet Med Assoc 1983; 183: 456-9.
• 7 Slocum B, Slocum TD. Tibial plateau leveling osteotomy for repair of cranial cruciate ligament rupture in the canine. Vet Clin North Am Small Anim Pract 1993; 23: 777-95.
• 8 Warzee CC, Dejardin LM, Arnoczky SP, Perry RL. Effect of tibial plateau leveling on cranial and caudal tibial thrusts in canine cranial cruciate-deficient stifles: An in vitro experimental study. Vet Surg 2001; 30: 278-86.