Comparison of Healing Process in Open Osteotomy Model and Closed Fracture Model

Objective: Comparison of the healing process in open osteotomy and closed fracture models that were used to study fracture healing.

Design: Randomized, prospective study in experimental animals, with a recovery duration of two and four weeks.

Setting: Unrestricted cage activity with weight bearing as tolerated.

Animals: Thirty-four skeletally mature, female New Zealand White rabbits.

Interventions: Closed fractures and open osteotomies of the tibial diaphysis were reduced and immobilized with four-pin, double-bar external fixators.

Main Outcome Measurements: Callus circumference was measured with a tape measure, bridging callus was assessed on biplane radiographs and evaluated histologically, and torsional stiffness and maximum torque were measured.

Results: Periosteum damage was more severe and hematoma formation was smaller in the osteotomy model, resulting in a delay in biological healing and restoration of the biomechanical properties.

Conclusions: Investigators should consider the difference between the closed fracture and open osteotomy models when selecting an animal model to investigate fracture healing.