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Previous studies have shown substantial effect thermal damage can have on new bone formation following osteotomy. In this study we evaluated the extent of thermal damage which occurs in four different methods of osteotomy and the effects it can have on bone healing. We further wanted to test whether a special osteotomy plate we constructed can lead to diminished heat generation during osteotomy and enhanced bone healing. The four methods evaluated included osteotomy performed by chisel, a newly constructed osteotomy plate, Gigly and oscillating saw. Twelve adult sheep underwent osteotomy performed on both tibiae. Bone fragments were stabilized using a fixation plate. Callus size was assessed using standard radiographs. Densitometry and histological evaluation were performed at 8 weeks following osteotomy. Temperature measurements were performed both in vivo during the operation, and ex vivo on explanted tibiae. The defects healed without complications and showed typical course of secondary fracture healing with callus ingrowth into the osteotomy gap. Radiographic examination of bone healing showed a tendency towards more callus formation in bones osteotomized using Gigly and oscillating saw, but this difference lacked significance. Use of Gigly and oscillating saw elicited much higher temperatures at the bone cortex surface, which subsequently lead to slightly impaired bone healing according to histological analysis. BMD was equal among all bones. In conclusion, the time required for complete healing of the defect differed depended greatly on the instruments used. The newly constructed osteotomy plate showed best results based on histological findings of capillary and osteoblast density.

There are contradictory opinions of the role of the periosteum in the conditions of stable osteosynthesis. One group of authors (Küntscher, 1970; Zucman et al., 1968) and others believe that the periosteum, especially its cambian layer, has one of the most important roles in the healing of fractures. However, other group of authors (McEven, 1912; Antony et al., 1980) and others deny the crucial role of the periosteum in the healing of fractures. The authors of the present study performed osteosynthesis by the Müller plate in both femoral bones of 20 dogs. In the left femoral bone, the periosteum was removed 4 cm in the proximal and distal direction from the fracture site, while in the right femoral bone the periosteum remained intact. The healing of the fracture was controlled by X-ray every 15 days up to 2.5 months when the animals were subjected to euthanasia. After 2.5 months from the introduction of the fracture, the healing of the fracture line was recorded in both femoral bones. It is concluded that in the conditions of stable osteosynthesis the periosteum does not play a crucial role in the healing of bones.