Evaluating Stiffness of Fibreglass and Thermoplastic Splint Materials and Inter-fragmentary Motion in a Canine Tibial Fracture Model.

Objectives:  Various materials are used to construct splints for mid-diaphyseal tibial fracture stabilization. The objective of this study was to compare construct stiffness and inter-fragmentary bone motion when fibreglass (FG) or thermoplastic (TP) splints are applied to either the lateral or cranial aspect of the tibia in a mid-diaphyseal fracture model.
Methods:  A coaptation bandage was applied to eight cadaveric canine pelvic limbs, with a custom-formed splint made of either FG or TP material applied to either the lateral or cranial aspect of the osteotomized tibia. Four-point bending tests were performed to evaluate construct stiffness and inter-fragmentary motion in both frontal and sagittal planes.
Results:  For a given material, FG or TP, construct stiffness was not affected by splint location. Construct stiffness was significantly greater with cranial FG splints than with cranial TP splints ( p  < 0.05), but this difference was not significant when comparing splints applied laterally ( p  = 0.15). Inter-fragmentary motions in the sagittal and frontal planes were similar across splint types for cranial splints, but for lateral splints there was a 64% reduction in frontal plane motion when FG was used as the splint material ( p  = 0.03).
Clinical Significance:  FG produces a stiffer construct, but the difference is not reflected in a reduction in inter-fragmentary motion. For lateral splints, FG splints are associated with reduced inter-fragmentary motion as compared with TP and may therefore have slight superiority for this application.
Competing Interests: None.
(Schattauer GmbH Stuttgart.)