Biomechanical properties of tendons during lower-leg lengthening in dogs using the Ilizarov method

Ten dogs were provided with a circular fixator. Segment resection of the fi bula and tibial osteotomy in the right lower leg was performed. 5 days afte r surgery, a lengthening of the right lower leg by 2.5 cm was performed on 6 dogs using a distraction rate of 0.5 mm, twice per day. 3 dogs with leg l engthening and 2 dogs of the control group without leg lengthening were sac rificed at the end f the distraction phase of 25 days and the remaining dog s after another 25 days. Postmortally the tendons of the tibialis anterior, extensor digitorum longus, peroneus longus and the achilles tendon were ta ken from the operated right side and the left non-operated control side and were examined biomechanically in cyclic tests. The control group without l engthening showed no changes in the biomechanical properties in the tendons of either side nor in those of the unlengthened left side of the operated dogs. In contrast the biomechanical tests revealed a marked decrease of the elastic modulus, an increase of distraction length and an increase of modu lus reduction on the lengthened side compared to the non-operated left side . (C) 1999 Elsevier Science Ltd. All rights reserved.