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.

• OA most often occurs at the ends of the fingers, thumbs, neck, lower back, knees, and hips.

Definition : is a degenerative joint disease in which there is progressive loss of articular cartilage and accompained by new bone formation and capsular fibrosis .

Pathology of OA

• Any joint can be affected

• Articular cartilage is slowly worn away

• Bone is exposed ( subchondral bone)

• Bone at the margines of joint hypertrophies to form ( osteophytes )

• Osteophytes eroded the synovial membrane

OA OA is a disease of joints that affects all of the weight-bearing components of the joint:

•Articular cartilage•Menisci•Bone

No extra articular features & no systemic illness

OA Nodal osteoarthritis Note bony enlargement of distal and proximal interphalangeal joints (Heberden's nodes and Bouchard's nodes, respectively).

OA is mainly a noninflammatory disease of synovial joints

No joint ankylosis is observed in the course of the disease

Non nodalo less prominent & affect distal interphalengeal joints

CLASSIFICATION OF OA

• Primary OA Secondary OA

Etiology is unknown Etiology is known

Age

• Age is the strongest risk factor for OA. Although OA can start in young

adulthood,if pateint is over 45 years old, He is at higher risk.

Female gender

• In general, arthritis occurs more frequently in women than in men. Before

age 45, OA occurs more frequently in men; after age 45, OA is more

common in women. OA of the hand is particularly common among women.

Joint mal-alignment

• People with joints that move or fit together incorrectly, such as bow legs, a

dislocated hip, or double-jointedness, are more likely to develop OA in those

joints.

OA – Causes & risk factors

Hereditary gene defect

• A defect in one of the genes responsible for the cartilage component collagen can cause deterioration of cartilage.

Joint injury or previous disease overuse caused by or sports

• Traumatic injury (ex. Ligament or meniscal tears) to the knee or hip

increases the risk for developing OA in these joints. Joints that are

used repeatedly in certain jobs may be more likely to develop OA

because of injury or overuse.

Obesity

• Being overweight during midlife or the later years is among the

strongest risk factors for OA of the knee.

OA – Risk Factors

OA – Symptoms• OA usually occurs slowly -

It may be many years before the damage to the joint becomes noticeable

• Only a third of people whose X-rays show OA report pain or other symptoms:

– Pain intermittent at first but later chronic in a joint

Worst in the evening , relieved by rest – Morning Stiffness or that tends to follow

periods of inactivity, such as sleep or sitting .– Disability

signs1-Swelling o r2- tenderness in one or more joints [not necessarily occurring on both sides of the body at the

same time] -3-Crunching feeling or sound of bone rubbing on bone

(called- crepitus) when the joint is use 4-Muscle wasting

5-Joint deformities

Osteoarthritis (OA)

Osteoarthritis may result from wear and tear on the joint

•The normal cartilage lining is gradually worn away and the underlying bone is exposed.

Osteoarthritis (OA)•The repair mechanisms of tissue absorption and synthesis get out of balance and result in osteophyte formation (bone spurs) and bone cysts

A case of the, “Which came first? The chicken or the egg?”

OA – Articular Cartilage

Articular cartilage is the main tissue affected OA results in:

•Increased tissue swelling•Change in color•Cartilage fibrillation•Cartilage erosion down to subchondral bone

OA – Articular Cartilage

OA – Articular CartilageThe 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

Osteoarthritis with lateral osteophyte, loss of articular cartilage and some subchondral bony sclerosis- X-ray shows loss of joint space

OA – Overall Changes

Asymmetrical joint space narrowing from loss of articular cartilage

The medial (inside) part of the knee is most commonly affected by osteoarthritis. 

OA – Radiographic Diagnosis

OA – Radiographic Diagnosis•Asymmetrical joint space narrowing

•Periarticular sclerosis

•Osteophytes

•Sub-chrondral bone cysts

OA – Arthroscopic Diagnosis

Normal Articular Cartilage

Ostearthritic degenerated cartilage with exposed subchondral bone

Arthroscopy allows earlier diagnosis by demonstrating the more subtle cartilage changes that are not visible on x-ray

Defferential diagnosis

1-Avascular necrosis

2-Inflammatory arthropathies

(a) Osteoarthritis with marked subarticularbone collapse is sometimes mistaken for osteonecrosis. Theclue to the diagnosis is that in OA the articular ‘space’(cartilage) is progressively reduced before bone collapseoccurs, whereas in primary osteonecrosis (b) articularcartilage is preserved even while the underlying bonecrumbles

Defferential diagnosis

3-Polyarthritis of the fingers

4-Diffuse idiopathic skeletal hyperostosis (DISH)

Treatement

• GENERAL ( rest , weight loss , suitable walking stick , change occupation )

• Drug treatment ( symptomatic relief by NASIDS ,For inflammatory ecxerbations by intraarticular corticosteroid )

• Physical therapy

• Surgical (Arthrodesis , Arthroplasty )

Non-Pharmacologic Treatment of OA

Patient educationWeight loss (if overweight)

Physical therapy Range-of-motion exercises Muscle-strengthening exercisesAssistive devices for ambulationPatellar tapingAppropriate footwear Lateral-wedged insoles (for genu varum)BracingOccupational therapyJoint protection and energy conservation

OA – Arthroscopic Treatment•In addition to being the most accurate way of determining how advanced the osteoarthritis is:•Arthroscopy also allows the surgeon to debride the knee joint

•Debridement essentially consists of cleaning out the joint of all debris and loose fragments. During the debridment any loose fragments of cartilage are removed and the knee is washed with a saline solution. •The areas of the knee joint which are badly worn may be roughened with a burr to promote the growth of new cartilage - a fibrocartilage material that is similar scar tissue. •Debridement of the knee using the arthroscope is not 100% successful. If successful, it usually affords temporary relief of symptoms for somewhere between 6 months - 2 years.

•Arthroscopy also allows access for surgical treatment of articular cartilage: graft-transplantation, micro-fracture techniques, sub-chondral drilling

OA – Non-operative Treatments

•Pain medications•Physical therapy•Walking aids•Shock absorption•Re-alignment through orthotics•Limit strain to affected areas

The ultimate solution for osteoarthritis of the knee is to replace the joint surfaces with an artificial knee joint:•Usually only considered in people over the age of 60•Artificial knee joints last about 12 years in an elderly population

•Not recommended in younger patients because:•The younger the patient, the more likely the artificial joint will fail•Replacing the knee the second and third time is much harder and much less likely to succeed.•Younger patients are more active and place more stress on the artificial joint, that can lead to loosening and failure earlier•Younger patients are also more likely to outlive their artificial joint, and will almost surely require a revision at some point down the road.

•Younger patients sometimes require the surgery (simply because no other acceptable solution is available to treat their condition)

Total Knee Replacement

•The ends of the femur, tibia, and patella are shaped to accept the artificial surfaces. •The end result is that all moving surfaces of the knee are metal against plastic

Total Knee Replacement

Total Knee Replacement

Total Knee Replacement

Photographs of total knee components on model bone

Total Knee Replacement

Questions