1. Osteoarthritis (OA)

2. Osteoarthritis
Most common form of arthritis , which shows a strong association with aging and is a major cause of pain and disability in the elderly , characterized by both degeneration of articular cartilage and simultaneous proliferation of new bone

3. Epidemiology
There is steady rise in overall prevalence from age 30 , such that by 65 years 80 % of people have some radiographic evidence of OA , though only 25 – 30 % have associated symptoms
Knee OA is more incidence than hip OA
Inheritance is a major attributable factor especially hand and generalized OA , But also for hip and generalized OA , but also for hip and knee OA

4. Epidemiology
OA is more common in female except for hip joint where both genders are equally affected
Trauma and occupation is very important factor as farming ( hip OA ) , mining (knee OA ) and professional foot ball ( knee OA )
The correlation between the presence of structural OA and pain and disability varies according to site , correlation is stronger at the hip than the knee and poor at most small joint sites

5. Etiology and pathogenesis
Primary OA ( Idiopathic )
Secondary OA
Previous trauma
Prior joint disease (JIA , RA , Gout , septic arthritis , hemophilia )
Metabolic or endocrine disease , chondrocalcinosis , hemocromatosis , acromegally

6. Etiology and pathogenesis
Neuropathic joint : tabes dorsalis
Syringomyelia
Late avascular necrosis :SLE , Sickle cell disease
Spondylo-epiphyseal dysplasia
Endemic OA

7. Pathogenesis
Cartilage changes in OA are highly characteristic
Enzymatic degeneration of aggrecan and collagen by aggrecanase , collagenase and stromelysin
Production of nests of chondrocytes ( metabolically active )
Turn over of aggrecan component is increased and eventually the concentration of aggrecan is decreased

8. Pathogenesis
The decrease of the size of the hydrophilic aggrecan molecules increases the water concentration and swelling pressure in the cartilage
Fissuring of the cartilage surface ( fibrillation )
Development of deep vertical cleft , localized chondrocyte death and decrease in cartilage thickness
These changes in OA cartilage encourage deposition of calcium pyrophosphate apatite crystals and formation of osteophyte

9. Pathogenesis
There is trabecular thickness in the subchondral bone , holes or cyst , often develop result from osteonecrosis due to increase intra osseous pressure
Despite central and marginal new bone formation with severe cartilage loss there may be attrition of bone , such attrition may ablate the trabeculae and lead to smooth , shiny surface ( eburnation )

10. Pathogenesis
Hyperplasia of the synovium with formation of osteochondral bodies which reflect chondroid metaplasia
Non specific type II fiber atrophy of the muscles overlying the joint

11. Pathological changes in OA
Remodeling of bone contour
Fibrillation and focal loss of hyaline cartilage
Marginal osteophyte
Subchondral sclerosis
Bone cysts
Secondary bursitis
Capsular thickening
Osteochondral body
Synovial hyperplasia
Secondary osteoplasia

12. Clinical features Pain and functional restriction
Causes of pain : increase pressure in subchondral bone ( cause night pain ) , trabecular microfracture , capsular distension , low grade synovitis , bursitis , and enthesopathy
The pain mainly related to movement and weight bearing , relieved by rest
Morning stiffness <15 minutes

13. Nodal generalized OA Polyarticular finger IPJ Heberden’s nodules
Bouchard’s nodules
Marked female predominance
Good functional outcome for hands
Predisposition to OA at other joints especially knees
Strong genetic predisposition
Affect middle aged women (40-50 years )
Lateral deviation of the fingers reflecting focal cartilage loss
Involvement of the first CMCJ resulting in thumb – base squaring

14. Heberden’s nodules Bouchard’s nodules

15. Knee OA
Affect patello – femoral and medial tibio – femoral compartment of the knee
Trauma is important risk factor
Mostly bilateral and symmetrical especially in women
Posterior knee pain suggest complicating popliteal cyst

16. Local examination Local examination revealed :
jerky asymmetric , antalgic gait
Varus or less commonly valgus or fixed flexion deformity
Weakness and wasting of the quadriceps
Restricted flexion / extension with coarse crepitus bony swelling around the joint line

17. Hip OA
Superior pole OA :usual pattern in man and most OA that is secondary to structural abnormality
Unilateral
Often progresses with superolateral migration of the femoral head
Has poor prognosis
Less common : central (medial ) OA.

18. Hip OA Central cartilage loss Confined to women Bilateral
May associated with nodal generalized OA
Uncommonly progresses either axial femoral migration
Better prognosis

19. Signs and symptoms
Correlation between symptoms and radiographic changes
Hip pain in the anterior groin , radiate to the buttock , anterolateral thigh , knee joint or shin
Lateral hip pain due to trochanteric bursitis
Antalgic gait
Weakness and wasting of quadriceps and gluteal muscles

20. Signs and symptoms
Pain and restrictions of internal rotation with hip flexed , which occur early
Anterior groin tenderness just lateral to the femoral pulse
Fixed flexion , external rotation deformity of the hip
Ipsilateral leg shortening

21. Investigations Normal full blood count , ESR , CRP
Synovial fluid is viscous with low turbidity and CPPD crystals may be identified in 50 % of patients
Plain radiographs shows focal narrowing of joint space , marginal osteophyte , subchondral sclerosis , cysts , osteochondral ( loose bodies ) and deformity
Tests to exclude secondary causes , as serum growth hormone , skull radiograph for acromegally , urine homogentistic acid for ochronosis

22. Patello-femoral J. OA

23. Osteophytes of knee J.

24. Osteophytes of the shoulder J.

25. OA of MCP J. – bony cyst

26. OA of MCP J.

27. Bony cyst –OA

28. Bony cyst –OA

29. OA – hip J.

30. OA – hip J.

31. OA – hip J.- bony cyst

32. Advanced OA – knee J.

33. Advanced OA – knee J.

34. MTP J OA

35. OA – cervical spine

36. OA – cervical spine

37. OA – lumbar spine

38. Advanced OA – lumbar spine