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33rd Annual Scientific Meeting proceedings


Stream:   |   Session: Resident Forum - Orthopaedic
Date/Time: 04-07-2024 (19:30 - 19:45)   |   Location: Auditorium 1
The effect of advancement rate on the mechanical properties of the cortical hinge when performing TTA-Rapid. An in-vitro study.
Yiapanis C1, Granovsky G2, Weissman S2, Ben-Amotz R*2, Milgram J*2
1Cyvets Veterinary Centre, Paphos, Cyprus, 2Veterinary Teaching Hospital, Koret School of Veterinary Medicine, Jerusalem, Israel.

Objectives:

The rate of advancement of the tibial crest when performing TTA Rapid is critical
to avoid hinge fracture, however, clear guidelines remain unavailable. The aim of this study was to determine if increased rate of advancement of the tibial crest causes failure and/or weakening of the cortical hinge during loading. In addition, changes in the bone distal to the osteotomy were characterized.

Methods:

Pairs of tibiae from large dogs were isolated with the attached patella and patellar ligament, and prepared for mechanical testing. Osteotomy of the tibial crest was
planned using radiographs acquired previously, and created using the recommended technique.
Tibia were held horizontally in a mechanical testing machine and tibial crests of the left and right legs were advanced, by applying tension to the patellar ligament, at 0.5 mm/min and 2.0 mm/min, respectively. A spacer was placed to maintain an advancement of 10.5 mm and the cortical hinge was loaded to failure by applying tension to the patellar ligament at 3.0 mm/min, with the tibia at an angle of 45°. Sections prepared distal to the osteotomy were viewed with a reflected light microscope to characterize bone damage.

Results:

Cracking of the bone propagated along the cement line in all specimens. None of the
specimens failed at the cortical hinge and no difference was found in the mechanical properties between the two groups.

Conclusions:

Our findings support the anecdotal inter-surgeon variation in rate of tibial crest advancement, and identify the cement line as the location of cracks distal to the cortical hinge.

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