The following is a summary of the “Changes of the subchondral bone microchannel network in early osteoarthritis,” published in the January 2023 issue of Osteoarthritis and Cartilage by Taheri, et al.

Researchers reported the discovery of a three-dimensional network of subchondral microchannels that extends from the innermost layer of cartilage to the bone marrow (i.e., cartilage-bone marrow microchannel connectors; CMMC). However, the role of CMMC in pathology is unclear. Here, we quantitatively assessed the association between CMMC microarchitecture and cartilage status and regional variations in early idiopathic osteoarthritis (OA). 

Human femoral heads from cadavers were divided into two categories: those with intact cartilage and those with early cartilage lesions. The thickness of the subchondral bone (SB), the number of CMMCs, the largest and smallest CMMCs, and the CMMC morphology were measured and compared. Each dependent variable was analysed for the role that joint region and cartilage health played. The number and shape of CMMCs varied by joint region but not cartilage health.  Contrarily, the minimum and maximum CMMC size varied depending on the joint location and cartilage health. Joints’ load-bearing region (LBR) consistently showed the lowest CMMC levels. 

Microchannel size was increased in early OA compared to non-pathological subjects, most notably in the femoral head’s non-load-bearing region (NLBR) and peripheral rim (PR). Additionally, in the early stages of OA, subchondral bone thinning was found to be a localised occurrence linked with areas of partial chondral defect. Investigator finding indicate that the microchannel network of SB is enlarged, and that SB as a whole suffers structural deterioration, in the early stages of idiopathic OA.