COMPARATIVE-STUDY OF CALLUS PERFORMANCE ACHIEVED BY RIGID AND SLIDINGPLATE OSTEOSYNTHESIS BASED UPON DYNAMIC-MECHANICAL ANALYSIS

Operative management of long bone fractures is considered to be the tr eatment of choice all over the world. This could be achieved either by intramedullary nailing or plating. The former allows delivery of stre sses into the fracture site, but it requires a well-equipped operating theatre and an experienced surgeon who is, unfortunately, continuousl y exposed to radiation. On the other hand, plates could easily be appl ied in every orthopaedic clinic, but the existing ones are rigid and p rotect the fracture site from stresses to which it is ordinarily expos ed. Recently, various experimental attempts have been made to provide plates which allow partial loading on the fracture site and enhance ca llus formation (secondary fracture healing). Bearing that in mind, a t wo-part sliding plate (SP) has been developed at the Orthopaedic Clini c of Patras University, which allows intermittent loading into the fra cture site. Both the conventional AO rigid plate and SP were applied t o osteotomized sheep radii. The dynamic properties of the callus were estimated with its two dynamic mechanical characteristics (dynamic mod ulus of elasticity and the relative loss factor), whereas its static p roperties (strength) were evaluated by measuring the ultimate bending strength. A superiority of callus produced by the sliding plate was ob served concerning all the parameters under consideration.