Summary
With internal fixation of fractures using a plate and screws, the stability of the fixation is achieved mainly by the force generated by either lag screws or plate screws. The plate protects the bone from overload. The important mechanism in the function of plate fixation is the friction between the undersurface of the plate and the bone surface. It has become evident that plate luting, i. e. interposition of a bone cement layer between the plate and the bone, will alter the transmission of expected forces due to improved contact between the plate and the bone. The purpose of this project was to evaluate the load/strain relationships that occurred following plate luting and to understand why this procedure improved the mechanical behaviour of plate fixation in equine bone. We measured the strain patterns that occurred in unplated, plated and luted equine third metacarpal and metatarsal bones under simulated physiological conditions. Plate application resulted in reduced strain under the plate and increased strain at the opposite cortex. Following plate luting, this effect was more pronounced. Hysteresis between the loading-unloading cycle was less pronounced in the luted plates. This indicated that plate luting increased the effect of strain protection.
Plate luting was shown to reduce the strain under the plate and to increase it in the transcortex, effectively increasing the effect of strain protection.
Key words
Luting - Equine metacarpus/metatarsus - Strain gauges - Strain/load curves - Stress protection
