Reducing damage to the periosteal capillary network caused by internal fixation plating: An experimental study

Abstract Background The importance of the periosteum in fracture healing is well-known. Preserving periosteal vascularisation is essential during internal plate fixation of fractures. Methods This was an experimental randomised, controlled animal study on nine sheep. Standard dynamic compression plate (DCP) and four different newly designed reefed plates, with different plate-bone contact surface areas and different reef directions, were fixated on to the tibia or radius. After two weeks the plates were removed and the underlying periosteum was analysed. Blood vessels were marked by immunohistochemical staining (CD31 and CD34), microphotographs were taken and blood vessels counted to calculate blood vessel density. Results Median blood vessel density beneath the standard plate was significantly lower than in the intact periosteum (18.0 vs 27.7 mm 3 /cm 3 ). Blood vessel density in the periosteum beneath plates with reefs was significantly increased compared with the intact periosteum, and was highest beneath the plate with the lowest bone-plate contact area and crosswise reefs (51.5 mm 3 /cm 3 ), followed by plates with transverse, oblique and longitudinal reefs, respectively. The direction of the reefs did not have much influence on the periosteal capillary network. Lower contact surface area seems to be the main factor that increases blood vessel density beneath the plates. Conclusions The results show that plates with lower contact surface area stimulate angiogenesis in the underlying periosteum, which results in much higher blood vessel density compared with standard DCP. A randomised clinical trial is needed to prove the clinical relevance of these findings.