Graft fixation issues in knee ligament surgery

The popularity of soft tissue grafts, particularly the semitendinosus and gracilis, has raised several issues with regard to graft fixation in cruciate ligament reconstruction. What is the force required by activities of daily living and a progressive rehabilitation program? Does soft tissue fixation alter the biological process of graft incorporation compared with the use of a bone plug? This article reviews the mechanical properties and use of fixation devices. Interference screw fixation of a patella tendon bone plug has been clinically reliable. Relative ease of fixation, acceptable initial strength, and fixation close to joint surfaces contribute to the popularity of cruciate ligament reconstruction with patella tendon bone plug. Biodegradable interference screw fixation of a bone plug is a reasonable alternative to metal screw fixation, which has several disadvantages. Many forms of tendon fixation are placed at a distance from the joint and rely on linkage materials, resulting in graft tunnel shear forces and possible tunnel expansion. Direct interference screw fixation may alleviate these detractions, but ultimate failure at time zero, particularly tibial fixation, may not allow for a progressive rehabilitation program, which our patients currently benefit from with interference fixation of a bone plug. Diminishing individual fiber movement within the tendon graft and the elimination of linkage materials will improve future soft tissue fixation.