Torsional comparative biomechanical test of modified tibial-plateau-leveling osteotomy plate and locking plate in canine synthetic tíbias

G Sembenelli,P.C Moraes,M.C.N Wittmaack,A.C Shimano,T.A.S.S Rocha,B.W Minto,L.G.G.G Dias

doi:10.1590/1678-4162-10442

G Sembenelli, P.C Moraes + Show 5 more

Open Access

https://doi.org/10.1590/1678-4162-10442

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Abstract

ABSTRACT The objective of this study was to develop a locked tibial-plateau-leveling osteotomy (TPLO) plate and to compare this implant with the conventional bone fixation method using a locked plate to determine bone stabilization against torsion forces. Maximum force, angle at peak torque, and stiffness values were determined. Ten synthetic tibias were used, divided into 2 groups. The results in Group 1 (modified TPLO plate) and Group 2 (locked plate) were assessed using analysis of variance and the means were compared using Tukey’s test at 5% probability. There were significant differences in the angle at peak torque and stiffness. The group Modified TPLO plate had higher mean values of stiffness compared with Group locked plate. Group locked plate showed a greater angle at peak torque compared with Group modified TPLO plate. All constructs failed due to tibial fractures distal to the plate. The modified TPLO plate presented higher stiffness indexes than conventional locked plate in torsion. The locked plate presented greater elasticity than modified TPLO plate having greater angle at the peak of torque.

Highlights

Comminuted fractures are biologically and biomechanically challenging
Group locked plate showed a greater angle at peak torque compared with Group modified tibial-plateau-leveling osteotomy (TPLO) plate
The distal and proximal segments of long bones are exposed to greater stress from torsion forces than the middle diaphyseal segment due to the proximity of the joint, which exerts significant force in the case of the proximal tibia (Markel et al, 1994)

Summary

Introduction

Comminuted fractures are biologically and biomechanically challenging. Non-sharing ofThe distal and proximal segments of long bones are exposed to greater stress from torsion forces than the middle diaphyseal segment due to the proximity of the joint, which exerts significant force in the case of the proximal tibia (Markel et al, 1994). We assumed that a modified TPLO plate might offer favorable biomechanical characteristics for proximal fractures with poor bone stock, because of the triangular arrangement of screws. Locked TPLO plates have more proximal holes than conventional locked plates, allowing adequate fixation of very small proximal fragments; they were not developed to reach distal portions of the tibia, making it impossible to treat comminuted diaphyseal fractures with small proximal fragments (Slocum and Slocum, 1993). The modified TPLO plate can be used in a minimally invasive procedure by allowing insertion of a larger number of screws in the proximal fragment through a small incision. If plates are carefully implanted to minimize damage to soft tissues required for repair, in particular the blood vessels that extend to the periosteum from the muscles and fascia, the bone repair process is optimized (Mckibbin, 1978)

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