The influence of soft tissue trauma on bone regeneration after acute limb shortening.

Reconstructing posttraumatic tibial defects is often challenging. Some authors recommend acute limb shortening. We determined whether soft tissue trauma affects the formation of regenerated bone after acute shortening and monofocal lengthening. Twenty-two rabbits were divided into two equal groups. In the test group, 90 minutes of ischemia and 30 minutes of tibialis anterior muscle contusion at 100 kPa induced substantially elevated pressure as an onset of compartment syndrome. The untreated hind limb acted as the paired control. An external fixator was applied and the limb was shortened 10 mm through bone resection. After a latency period, distraction was performed for 10 days until the natural length was restored. New bone formation was evaluated mechanically, radiographically, and histomorphometrically. Osseous consolidation occurred in all animals. Normalized mechanical values of the newly reconstructed tibia indicated torsional strength was lower in the trauma group than in controls (46% +/- 18.5% versus 64% +/- 16.7%). Average normalized callus diameters were smaller in the trauma group than in controls (1.27 +/- 0.14 versus 1.6 +/- 0.16), as were callus volumes (37% +/- 5.9% versus 44% +/- 10.3%). Although soft tissue trauma affected the formation of regenerated bone, our results suggest reconstruction of tibial defects using a monofocal technique is consistent, even in the presence of blunt trauma and elevated compartment pressure.