Small Animal Orthopaedics Q&A 01

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An intraoperative photograph of the trochlear ridges of the femoral condyle which have been exposed by a medial arthrotomy and lateral dislocation of the patella.

Question	Answer		Article
What are the pathologic structures present on the trochlear ridges?	There is extensive osteophyte development along the abaxial surfaces of the trochlear ridges.		[[|Link to Article]]
Describe, on a microstructural level, how these structures develop.	Osteophytes develop in response to inflammation of the synovial tissues. Osteophytes develop primarily at the junction of the synovium and bone. When the synovium becomes inflamed, non-specific mutogenic factors are present within the fluid and the capsular tissues. Vascularity increases to the joint as a whole. Cells adjacent to bone proliferate and appear to be directed along the chondrogenic/osteogenic pathway of differentiation rather than the fibrogenic path, as occurs in the rest of the capsule. The fact that osteophytes are derived from tissue adjacent to bone or the proximity of bone matrix itself may be influencing factors. Continued presence of stimulatory factors leads to matrix deposition, mineralization and growth of osteophytes. Once established, osteophyte expansion may also proceed by surface growth. The mineralized areas develop a trabecular architecture and often retain a cartilage surface. Mature osteophytes may become incorporated into the metaphyseal trabecular structure during remodeling.		[[|Link to Article]]