Osteoarthritis. Osteoarthritis (OA). OA is the most common form of arthritis and the most common joint disease Over 10 million Americans suffer from OA of the knee alone Most of the people who have OA are older than age 45, and women are more commonly affected than men.
Nodal osteoarthritis Note bony enlargement of distal and proximal interphalangeal joints (Heberden's nodes and Bouchard's nodes, respectively).
Hereditary gene defect
Joint injury or overuse caused by physical labor or sports
Osteoarthritis may result from wear and tear on the joint
The repair mechanisms of tissue absorption and synthesis get out of balance and result in osteophyte formation (bone spurs) and bone cystsOsteoarthritis (OA) - Definition
A case of the, “Which came first? The chicken or the egg?”
A) Normal articular cartilage from 21-year old adult (3000X)
B) Osteoarthritic cartilage (3000X)
The surface changes alter the distribution of biomechanical forces further triggering active changes by the tissue
The cartilage damage causes chondrocyte cloning in an attempt to restore articular surface (Normal adult chondrocytes are fully differentiated and do not proliferate)
(A) Normal articular cartilage (B) Osteoarthritic cartilage
Unlike aging, OA is progressive and a significantly more active process
Osteoarthritis with lateral osteophyte, loss of articular cartilage and some subchondral bony sclerosis- X-ray shows loss of joint space
Asymmetrical joint space narrowing from loss of articular cartilage
The medial (inside) part of the knee is most commonly affected by osteoarthritis.
Ostearthritic degenerated cartilage with exposed subchondral bone
OA – Arthroscopic Diagnosis
Arthroscopy allows earlier diagnosis by demonstrating the more subtle cartilage changes that are not visible on x-ray
Photographs of total knee components on model bone