Force-displacement behaviour of biological tissue during distraction osteogenesis

Limb lengthening and bone transport treatments are used frequently, and com plications during treatment are common. Knowledge of the origin of tensile forces which resist distraction and the force-displacement response of biol ogical tissues during extension would assist in reducing complication rates . Two tibial diaphyseal lenthenings carried out using an Ilizarov fixator w ere monitored by a displacement transducer to determine extension of the le ngthening tissue (the regenerate bone), and by force transducers to determi ne tensile forces in the tissues that resist extension. The position of the force vector within a cross-section of the limb at the regenerate (provide d by CT) was used to determine the origin of these forces. The muscle group s and adjacent fascia resisting extension were the gastrocnemius in one sub ject and the anterior and peroneal compartments in the other. In response t o distraction, these tissues had relatively high stiffness ( > 200 N/mm), l ess "immediate" displacement ( < 35% of long term non-recoverable displacem ent) and inconsistent force relaxation properties (0-90%). In contrast, whe n the force vector was located in the vicinity of the regenerate, tissue ex hibited lower stiffness ( < 50 N/mm) and more immediate displacement ( > 65 % of long term nonrecoverable displacement), but also exhibited inconsisten t force relaxation (0-67%). (C) 1999 IPEM. Published by Elsevier Science Lt d. All rights reserved.