Histological evaluation of intraarticular osteochondral fragments

Abstract

Summary Scientific studies, investigating the aetiology of osteochondrosis focus mainly on the articular-epiphyseal cartilage complex and the growth plate. In osteochondrosis dissecans cleft formation through the necrotic cartilage leads to the formation of intraarticular osteochondral fragments. In contrast to osteochondral fragments located at typical predilection sites, a causative allocation of fragments located at different sites may be more challenging. Only limited numbers of studies have focused on the histological appearance of osteochondral fragments. They are mainly limited to the identification of types of tissue present, but do not further investigate possible specific characteristics and differences of involved components.The aim of the present study was to histologically evaluate osteochondral fragments more in detail to identify possible characteristics which may allow a causative and topographical allocation. A total of 76 osteochondral fragments were examined by two blinded observers. Signs of bone remodeling, enchondral ossification and proteoglycan staining properties were graded semi-quantitatively. The appearance of fibrous tissue or enchondral ossification at the separation border as well as the presence of ligamentous attachments were graded qualitatively. The articular cartilage present was evaluated applying the Mankin score. Significant differences in enchondral ossification (within the fragment and at the separation border), proteoglycan staining properties, the appearance of fibrous tissue at the separation border as well as differences in bone remodeling and in the Mankin scores were detected in osteochondral fragments from different locations. It was concluded that histological evaluation of osteochondral fragments may help in their aetiological allocation and may contribute to future understanding of the disease.