Calcified cartilage is suggested to be involved in the pathogenesis of osteoarthritis (OA) by facilitating endochondral ossification at the bone-cartilage unit. Therefore, the objective was to quantify the volume and surface area of the calcified cartilage in the femoral head in OA patients and healthy subjects.
We used design-based stereological principles, i.e., systematic uniform random sampling and vertical uniform random sections of the entire femoral head. We investigated the articular and calcified cartilage and femoral head surface area and volume, excluding fovea capitis and marginal osteophytes, in 20 patients with OA and 15 healthy subjects.
The volume of the calcified cartilage was significantly larger for the patients with OA compared with the healthy subjects (mean difference [95% CI]) (284 [110,457] mm
Patients with OA had a larger femoral head surface area and more calcified cartilage compared to healthy subjects. The volume of the calcified cartilage correlated positively with the volume of the femoral head for patients with OA, but not for healthy subjects. This strongly supports the existing view that bone growth in OA is associated with endochondral ossification.