1. Learning Objectives Degenerative joint disease (Osteoarthritis)
Rheumatoid Arthritis
Gout
Infectious arthritis
Ganglion and Synovial Cysts
Pigmented Villonodular Tenosynovitis and Giant-Cell Tumor of Tendon Sheath

3. Most common joint disorder, part of aging
Osteoarthritis
Most common joint disorder, part of aging
Annual economic toll in the United States > $33 billion
Degeneration of articular cartilage, structural changes in underlying bone are secondary

4. Osteoarthritis
Primary osteoarthritis: usually oligoarticular, in elderly
Secondary osteoarthritis: < 5% cases, in younger patients
Previous Traumatic Injury
Developmental Deformity
Diabetes
Ochronosis
Hemochromatosis
Marked Obesity

5. Osteoarthritis Knees & hands – more commonly affected in women
Hips - more affected
in men

6. Morphology
Enlargement, proliferation, and disorganization of chondrocytes in superficial part of articular cartilage
Increase in water content of matrix, decrease in proteoglycans
Above: normal hip articular cartilage stained with brilliant red showing abundant acid mucopolysaccharide except in superficial zone.
Below: degenerative changes (diffuse hypercellularity and extensive loss of acid mucopolysaccharide from matrix, as shown by diminished red dye)

7. The normal cartilage has smooth articular surface while OA cartilage shows fibrillation, fissuring of articular surface and clustering of cells in superficial zone
Fibrillation

8. Morphology A: Fibrillation of the articular cartilage
B: Severe osteoarthritis with (1) Eburnated articular surface exposing subchondral bone, (2) Subchondral cyst and (3) Residual articular cartilage

9. Eburnation of joint surface
Bilateral osteoarthritis of femur with eburnation of anterior joint surface
Polished ivory-like appearance of head of femur v/s normal

10. Loose Bodies
Lateral radiographs of 2 knees showing the typical location of symptomatic (left) and asymptomatic (right) loose bodies in the osteoarthritic knee. Symptomatic loose bodies are anterior to the knee in the suprapatellar pouch and are mobile. Asymptomatic loose bodies are posterior to the knee and because they are trapped in a Baker’s cyst they are not mobile and do not cause mechanical symptoms of locking
Small fractures can dislodge pieces of cartilage and subchondral bone into the joint, forming loose bodies (joint mice)

11. Subchondral cysts
The fracture gaps allow synovial fluid to be forced into the subchondral regions to form fibrous walled cysts

12. Osteophyte ("spur") formation
Mushroom-shaped osteophytes (bony outgrowths) develop at the margins of the articular surface
Osteophytes in Spine
Histology of osteophyte in proximal interphalangeal joint

13. Chondrocyte function affected by Mechanical stress, Aging
Imbalance of normal chondrocyte function can lead to osteoarthritis
Chondrocyte function affected by Mechanical stress, Aging

14. Diminished collagen network and increased chondrocyte apoptosis compromises cartilage tensile strength and resilience

15. Clinical Course Affects patients beginning in their 50s and 60s
Pain: is the most common complaint, initially during activity, relieved by rest. Later at rest also
Morning stiffness: lasts less than half hour
Crepitus: crackling sensation on moving the joint

16. Heberden nodes in fingers - prominent osteophytes at the distal interphalangeal joints, are characteristically seen in women a b
Bony enlargement seen in proximal interphalangeal joints (Bouchard’s nodes - a) distal interphalangeal joints (Heberden’s nodes - b)
The x-ray of OA shows "joint space" narrowing (indicating loss of articular cartilage), marginal osteophyte formation, and subchondral bony sclerosis

17. Clinical Course
Osteophyte impinge on spinal foramina - nerve root compression (radicular pain, muscle spasms, muscle atrophy, neurologic deficits)

18. Clinical Course Can stabilize for years but is slowly progressive
No predicted way to prevent/halt progression
Although significant joint deformity can occur, unlike rheumatoid arthritis, fusion does not take place
Treatment: maintaining healthy weight and exercising regularly, anti-inflammatory drugs, Joint Replacement Surgery

19. SUMMARY Osteoarthritis - most common form of joint pathology
Primary degenerative disorder of articular cartilage with matrix breakdown exceeding synthesis, inflammation is secondary
The vast majority of cases - without apparent precipitating cause except increasing age