Thickness of the substantia compacta of porcine long bones

Abstract

Mechanical load on the bone influences bone tissue and its inner tension, subsequently affecting bone formation and its histological structure. A precise understanding of this load and the development of strategies to influence it would contribute to principles of fracture management and to solving other bone pathologies of both humans and animals. The long bones of the thoracic and pelvic limb of a pig were here used as possible models to test new devices and implant materials. The purpose of this study was to investigate the thickness of compact bone of the diaphysis of porcine long bones and to establish ideal insertion points for tensometer probes, where 2.3 mm is the minimal required thickness, and to evaluate the histological structure of the compact porcine bone. A total number of 96 long bones from 12 pigs was investigated. The investigations consisted of morphometric assessment of the diaphysis of the bones by measuring thickness of the compact bone in different segments of the diaphysis and of microscopical evaluation of the compact bone. Macroscopical assessment of the bones revealed that the minimal required thickness of 2.3 mm of compact bone was found only in the middle and distal segment of the humerus, middle segment of the femur, proximally only on cranial aspect. The radius showed suitable thickness on the medial aspect of its proximal segment and on the lateral and caudal aspect of the middle segment. Tibial compact bone is suitable across the whole middle segment and on its lateral and medial aspect of the distal segment. Microscopical structure of the compact bone revealed characteristics of growing/immature bone characterised by both lamellar and osteonic bone. This study confirms the suitability of porcine radius and tibia for tensometer testing. However, one needs to take into account the different thickness of different parts of the bone planning experiments using tensometers.