Effects of Angled Dynamic Compression Holes in a Tibial Plateau Levelling Osteotomy Plate on Cranially Directed Fragment Displacement.

Abstract

OBJECTIVE: &#x2003;To compare angled dynamic compression holes in a tibial plateau levelling osteotomy (TPLO) plate to a commercially available TPLO plate in an ovine cadaveric model. STUDY DESIGN: &#x2003;Ovine tibias (40 bones) were mounted on a custom-made securement device and radiopaque markers were placed to aid radiographic measurements. A standard TPLO procedure was performed on each tibia with either a custom-made six-hole 3.5&#x2009;mm angled compression hole plate (APlate) or a six-hole 3.5&#x2009;mm standard commercial plate (SPlate). Radiographs were obtained before and after tightening of the cortical screws and evaluated by an observer blinded to the plate. Measurements of cranio-caudal displacement (CDisplacement), proximo-distal displacement (PDisplacement) in relation to the long axis of the tibia, and change in tibial plateau angle (TPA) were determined. RESULTS: &#x2003;CDisplacement was significantly greater in APlate (median 0.85&#x2009;mm, Q1-Q3: 0.575-1.325&#x2009;mm) compared to SPlate (median 0.00&#x2009;mm, Q1-Q3: -0.35-0.50&#x2009;mm, p&#x2009;<&#x2009;0.0001). There were no significant differences in the PDisplacement (median 0.55&#x2009;mm, Q1-Q3: 0.075-1.00&#x2009;mm, p&#x2009;=&#x2009;0.5066) or TPA change (median -0.50&#xb0;, Q1-Q3: -1.225-0.25&#xb0;, p&#x2009;=&#x2009;0.1846) between the two plate types. CONCLUSION: &#x2003;APlate increases cranially directed displacement of the osteotomy in a TPLO procedure without causing TPA change. The reduced interfragmentary distance across the whole osteotomy could improve osteotomy healing compared to standard commercial TPLO plates.