Microcomputed tomographic examination of the osseous structures of the canine carpus

Abstract

The surgical treatment of carpal joint injuries is associated with a high implant-based complication rate of up to 50 %. For this reason, the aim of the study was to create a database on the bony microarchitecture of the cancellous and cortical structures of the carpus. A total of 80 carpal joints from 20 medium-sized dogs and 20 toy breeds were examined and compared with each other using microcomputed tomography. The parameters bone volume (BV/TV), bone surface (BS/BV), trabecular thickness (Tb.Th), number of trabeculae (Tb.N), trabecular spacing (Tb.Sp), degree of anisotropy (DA) and connectivity density (Conn. D) were measured and compared. In addition, the cortical structure was classified using a three-staged scoring system. It was shown that all carpal bones have a cancellous structure, that differs clearly between the groups, without one group being mechanically superior. The evaluation implies, that the second carpal bone appears to be very stable. The formation of the cortex differs massively between the groups, with the toy breeds having only a very thin, partially interrupted bone lamella, whereas the medium-sized dogs have a normal cortex. Within the toy breed group inhomogeneous results were observed, whereby the values of the Chihuahuas deviated. This breed had significantly fewer (Tb.N) and thinner trabeculae (Tb.Th) with a greater trabecular separation (Tb.Sp), lower bone volume fraction (BV/TV) and higher bone surface (BS/BV). This indicates a decreased stability of the Chihuahua's carpal bones. The results of this study could potentially improve the development of new implants and thus reduce the complication rate.