Ridges and grooves on the bony surfaces of osteoarthritic joints

Osteoarthritis (OA) is associated with disruption of the articular cartilage and remodeling of subchondral bone. However, the macroscopic changes seen on the surface of the underlying bone have received little attention. Deep parallel ridges and grooves of the subchondral, eburnated bone have been observed in palaeopathological skeletons with OA. The same phenomenon has been seen in contemporary bones treated to remove soft tissues. Four such specimens were examined in detail and the characteristics of the ridges were documented by reflex microscopy. The depth and peak-to-peak distance of the grooves varied considerably. In each case there was matching of ridges and grooves on the two articulating surfaces of the joint, which fitted together like cog-wheels. This previously undocumented aspect of the pathology of OA may have significance to the function and outcome of an osteoarthritic joint, raises questions on the nature and control of subchrondal bone changes in OA.