This research was conducted at The Veterinary Orthopedic Research Laboratory, and the Orthopaedic BioMaterials Laboratory, The Ohio State University, Columbus, OH. Funding provided by the Veterinary Orthopedic Research Laboratory, The Ohio State University. Presented in part at the American College of Veterinary Surgeons Symposium, Washington, DC, October 2006.
Biomechanical Comparison of Two Alternative Tibial Plateau Leveling Osteotomy Plates with the Original Standard in an Axially Loaded Gap Model: An In Vitro Study
Article first published online: 30 DEC 2008
© Copyright 2009 by The American College of Veterinary Surgeons
Volume 38, Issue 1, pages 40–48, January 2009
How to Cite
KLOC, P. A., KOWALESKI, M. P., LITSKY, A. S., BROWN, N. O. and JOHNSON, K. A. (2009), Biomechanical Comparison of Two Alternative Tibial Plateau Leveling Osteotomy Plates with the Original Standard in an Axially Loaded Gap Model: An In Vitro Study. Veterinary Surgery, 38: 40–48. doi: 10.1111/j.1532-950X.2008.00464.x
Dr. Kowaleski's current address is Cummings School of Veterinary Medicine at Tufts University, North Grafton, MA.
Dr. Johnson's current address is University of Sydney, Australia.
- Issue published online: 30 DEC 2008
- Article first published online: 30 DEC 2008
- Submitted July 2007; Accepted June 2008
Objective— To compare the axial compression stiffness of osteotomized canine tibiae stabilized with Slocum, Securos, or Synthes plates after a tibial plateau leveling osteotomy (TPLO) procedure.
Study Design— In vitro, paired comparison of cadaveric tibial constructs subjected to mechanical testing under an axial load.
Sample Population— Canine tibiae (n=16 pairs) from skeletally mature male and female dogs of various breeds (18–55 kg).
Methods— Tibial pairs (n=16) were randomly assigned to 1 of 2 study cohorts (n=8 pairs/cohort): cohort 1, tibial osteotomy stabilization with a Slocum or a Securos plate, or cohort 2, tibial osteotomy stabilization with a Slocum or a Synthes plate. One tibia from each pair was stabilized with 1 of each plate design assigned to the cohort after TPLO. A 3.2 mm osteotomy gap was maintained during plate application in all constructs. Load and axial displacement were recorded while constructs were loaded to 2000 N in axial compression. Failure loads were not reported because no distinct yield point or failure point was evident within the load range for many specimens. Failure modes were recorded for each construct, and photographs of typical failures were obtained. Stiffness (N/mm) was calculated from load–displacement curves. Paired comparisons of mean stiffness were performed within study groups using a paired t-test. Significance was set at P<.05.
Results— The mean construct stiffnesses for the Slocum (383±183 N/mm) and Securos (258±64.1 N/mm) constructs were not significantly different (P=.164; power=0.566). The mean construct stiffness for the Synthes constructs (486±91.0 N/mm) was significantly greater than that of the Slocum constructs (400±117 N/mm); P=.0468. Modes of failure for the Slocum (16/16) and Securos (8/8) constructs included plastic deformation of the implant with valgus deformity combined with fibular luxation (2/16 Slocum; 1/8 Securos) or fibular fracture (2/16 Slocum; 4/8 Securos). Most Synthes constructs underwent elastic deformation (7/8). One Synthes construct fractured in the saggital plane through the tibial plateau depression at the point of load application.
Conclusions— The Slocum and Securos plate/tibia construct have similar stiffness, whereas the Synthes/tibia constructs are significantly stiffer than the Slocum/tibia constructs. Modes of fixation failure observed in this model were consistent with TPLO fixation failures observed clinically.
Clinical relevance— Construct stiffness in axial load varies with implant type. Implants that confer higher stiffness to the construct may result in greater fixation stability in tibial metaphyseal osteotomies.