A comparative study of different methods of tendon lengthening: an experimental study in rabbits

Three different techniques of tendon lengthening--Z-lengthening, intramuscular lengthening, and tenotomy--were studied in rabbits. The cut tendon ends were marked with radioopaque sutures. The repair process was similar with all three techniques, with healing being completed by 6 weeks. With intramuscular lengthening, the gap distance remained constant throughout the experiment, whether immobilization was used or not. Thus, immobilization is not necessary with this technique. In contrast, with tenotomy the gap distance increased significantly when immobilization was not used. However, with immobilization the distance remained constant throughout the experiment. Immobilization is necessary after tenotomy to prevent undue lengthening of the tendon.