Subchondral bone remodelling in osteoarthritis

Abstract

Subchondral bone remodelling is an integral part of osteoarthritis and involves the development of subchondral sclerosis seen on plain imaging, along with osteophyte formation.The development of these changes is due to persistent abnormal mechanical stresses which create a cellular and biomolecular response to microfractures in the subchondral bone and osteochondral junction.An early sign is bone marrow lesions seen on MRI scanning. Healing can occur at this stage by correcting the abnormal loads. Persistence leads to what is thought to be a delayed union or nonunion response by the bone.Microfractures of the osteochondral junction, coupled with articular cartilage fissuring and loss, allows synovial fluid to penetrate the subchondral bone along with cytokines and other molecules reacting with the bone cells to increase the pathological effects.This review gives an overview of the current thoughts on subchondral bone remodelling in osteoarthritis that is aimed at orthopaedic surgeons to help in the understanding of the pathogenesis of osteoarthritis and the role of surgical management. Cite this article: EFORT Open Rev 2019;4 DOI: 10.1302/2058-5241.4.180102.

Keywords: bone remodelling; osteoarthritis; subchondral.

Fig. 1.

Diagram showing the structure of the osteochondral junction

Fig. 2.

Proposed scheme for the development of bone marrow lesions and progression of osteoarthritis (based on data from Hügel and Guerts)

Fig. 3.

Matched Magnetic Resonance (MR) and histology images at (top row) medial and (bottom row) lateral tibial plateau. Note the area of homogeneous low signal on MR (white arrowheads) corresponds to an area of trabecular thickening on histology (black arrowheads). (reproduced from Mackay et al, with permission from Elsevier)

Fig. 4.

Diagram showing the cells involved in bone remodelling. Note the perforation of the osteochondral junction by an osteoclast taking blood vessel and sensory nerve supply into the deep layer of articular cartilage

Fig. 5.

Proposed scheme for the development of osteoarthritis in a post-traumatic model (based on data from Weber et al)

Fig. 6.

Diagram of the biomolecular interactions in osteoarthritis (original drawing, adapted from Suri and Walsh)

Fig. 7.

Diagram of the interaction of synovial inflammation and mechanical subchondral damage in osteoarthritis (original drawing, adapted from Hügel and Guerts)