Osteoarthritis and Joint replacement Flashcards
Define osteoarthritis:
Degeneration of joint cartilage and the underlying bone, most common from middle age onward. It causes pain and stiffness, especially in the hip, knee, and thumb joints.
What is the usual cause of osteoarthritis? (primary vs secondary).
Usually primary.
Secondary causes: Joint disease, haemochromatosis, obesity, or occupational.
What are the signs and symptoms of osteoarthritis?
(Often knee or hip): Pain, crepitus upon movement, with background ache at rest.
Worse with prolonged activity.
Morning stiffness - usually lasts an hour.
How is the pain in OA described?
Sharp ache or burning sensation.
- worse with prolonged activity.
How does osteoarthritis present on x-ray?
(LOSS)
Loss of joint space
Osteophytes
Subarticular sclerosis
Subchondral cysts
What is the general treatment for osteoarthritis?
Core treatment: Exercise to improve local muscle strength and aerobic fitness. Weightloss if overweight.
Analgesia: Regular paracetamol, topical NSAID’s
Intra-articular steroid injections relieve pain in severe cases.
Surgery: Joint replacement (hip or knee) is the best option in severe OA that is having a large impact on quality of life. QoL operation.
What is the difference between rheumatoid arthritis and osteoarthritis?
RA - attacks the lining of the joint (the synovial membrane).
OA - is a disease of the cartilage.
Note: you can get secondary OA in a joint affected by RA.
What is the main cartilage affected in OA?
Articular cartilage.
What cells are responsible to maintaining cartilage?
Chondrocytes
What are the risk factors of osteoarthritis?
Age
Inflammation - Can increase action of degradative enzyme thus breaking down cartilage or inhibit synthetic enzymes which are involved with cartilage formation.
Joint injury
Mechanical stress
Neurologic disorders
Medications
Pathology of OA when articular cartilage is damaged:
- Response chondrocytes.
- Immune response.
They start by making less proteoglycan and more type 2 collagen.
However they soon switch to start making type 1 collagen which doesn’t interact with the proteoglycans in the same way.
This leads to a decrease in the elasticity of the cartilage matrix causing it to break down.
Cartilage becomes softer and weaker and begins to flake off into the synovial space - called joint mice.
Lymphocytes and macrophages are recruited into the synovial membrane to remove the debris - they produce pro-inflammatory cytokines which leads to inflammation of the synovium. Called synovitis.
Fibrilations (cracks) form on the articular surface.
Eburnation from bone rubbing on bone.
Growth of osteophytes on the edge of the bone.
Osteophytes can be notably seen where?
Metacarpal joint’s
- Heberden nodes
- Bouchard nodes
Osteoarthritis presentation vs rheumatic arthritis:
What is the significance of the decrease in proteoglycan content by chondrocytes when cartilage is damaged?
Proteoglycan loss results in an inability to hold on to water content:
- Decreased resistance to compression – especially with repeated stress
Primary OA
Secondary OA
