Review of SK ESF Mechanics
by IMEX Veterinary
The most powerful way to simplify the ESF method lies in mechanical frame improvements that are not dependent on full-pins or complex frame geometries. In this respect, the SK ESF System is designed to be dramatically different from the KE and new KE-like systems that utilize traditional 1/8” and 3/16” connecting rods.
Mechanical testing of KE frames reveals the connecting rod as the “weak link” of simple fixator frames. In retrospect, the choice of KE rods utilized was and still is poorly matched to veterinary pin diameters and patient demands; dictating that veterinary surgeons utilize complex ESF frames. By eliminating the weak link of simple frames, the SK ESF System provides a simple but powerful alternative to complex frame geometry.
FIGURE 1 | Mechanical testing of Type I-a frames demonstrates that the traditional external rod is the weak link. Bending of the rod is not usually permanent, but results in premature pin loosening and poor limb function. Complex frames can hide weak rods. Strong rods are mandatory to achieve simple but strong frames. (See “Bending Stiffness Comparison of External Rods” chart shown below, which contains previously collected data.)
FIGURE 2 | Bending Stiffness Comparison of External Rods
Simple frames, the ability of clamps to effectively grip a wide range of different pin diameters, and the need for minimal instrumentation make the SK ESF System the most economical ESF choice. Reduced use of full-pins minimizes pin tracts and related morbidity while simplifying staged disassembly and post-operative care. Most importantly, use of half-pins instead of full-pins encourages and facilitates optimal pin centering and use of safe pin corridors.