what are the changes of the articular cartilage in osteoarthritis
Loss of superficial chondrocytes (necrosis)
Isogenic proliferation of chondrocytes with larger extracellular matrix regions
Duplication of tide mark
Loss of collagen scaffold and proteoglycans
what does osteoarthritis primarily effect
- primarily effects the articular cartilage
define pseudo-laxity
When a ligament no longer has to span the same distance in a joint as before; results when there is persistent inflammation of the synovium, caused by progressive erosion of the articular joint due to joint space narrowing.
Why does pseudo laxity happen in osteoarthritis
- the space between the joint capsule decreases this means that there is a smaller distance between the two joints
- therefore the collateral ligaments sublax
what are the three clinical symptoms of osteoarthritis
- pain on use
- short lived morning stiffness
- functional limitation
What are the 3 clinical signs of osteoarthritis
- crepitus
- restricted movement
- bony enlargement
What are the risk factors for developing osteoarthritis
- older age
- women
- obesity
- joint injury
- long term overuse of the joint
- genetics
- malformed joints such s knocked knees
- inactivity
What are the lifestyle treatments for osteoarthritis
- exercise - strength muscle and decrease joint pain and increase flexibility
- weight loss if overweight
- change the way you walk
what are the medication options of OA
- paracetamol and/or topical NSAID
- COX -2 inhibitors
- give intra-articular injections = corticosteroid injections
name non pharmacological treatment for OA
Exercise – core treatment
- Local muscle strengthening
- General aerobic fitness
- Weight loss
Transcutaneous electrical nerve stimulation (TENS) as an adjunct for pain relief
Aids and devices
- Orthopaedic insoles
- Walking stick
lifestyle changes
diet
Thermotherapy
- use of local heat or cold
Nutriceuticals
- increase intake of omega 3 rich foods
- Chondroitin sulphate and glucosamine supplements – no longer recommended that they should be recommended or approved
What are the surgical options for OA
Arthroscopic lavage – not used, soemtiems they do it to have a look inside
Arthroscopic lavage plus debridement – normally lavage plus now
Microfracture
Mosiacplasty (osteochondral transplant)
Chondrocyte grafts
Joint replacement
When should surgery be offered for those with OA
when they wake up during the night
- pain is now unbearable and effects there quality of life
describe an antalgic gait
Short stepping
Asymmetrical stride length
Step length on affected side is shorter
Unaffected limb brought forward more quickly than normal in swing phase
Duration of stance phase increased on normal side
What are the phases of walking
stance and swing phases
describe the stance and swing phase
Stance
- Begins with heel strike and ends when toe leaves the ground
- 60% of cycle
- 5 segments
Swing
- 40% of walking cycle
- Begins with toe off
- 3 segments
describe how walking occurs
Stance
- Intintial contact (Heel strike) - Foot inverted and dorsiflexed as heel makes contact on lateral side
- Loading response - Foot brought into full contact, ankle rocker action begins
- Midstance - Body weight brought over to the planted foot
- Terminals stance – (heel off) Heel lifted off ground (foot everted and plantar flexed). Body weight advances ahead of single-supporting foot
- Pre-swing (toe off) - Lower limb positioned to quickly swing forward beneath body, transfer of weight from one limb to other
Swing
- Initial swing - foot pushed off ground, limb accelerates forward
- Mid swing - Limb moves beneath body until tibia of leg is vertical. Foot dorsiflexed to prevent toes dragging on ground
- Terminal swing - Limb decelerates forward movement, prepares for initial contact again
1 What are three main classes of oral analgesics on the analgesic ladder? (3 marks)
simple analgesics and NSAIDs NSAIDs plus weak opiods Stronger opiods
2 What are the 4 main signs of OA that you would find on an x-ray? (2 marks)
loss of joint space subchondral sclerosis osteophytes
trabeculae fractures subchondral cysts
What biochemical changes are observed in the osteoarthritic articular cartilage? (2 marks)
Reduced proteoglycan content Change from collagen type 2 to type 1
Name the three articulations that make up the knee joint. (3 marks)
Lateral femoral and tibia condyles with corresponding meniscus
Medial femoral and tibia condyles with corresponding meniscus
Patella with the femur
• What is the name of the proteoglycan complexes that you find in articular cartilage?
aggrecan
• Explain why weight bearing joints are more likely to develop osteoarthritis?
They are under more mechanical stress so the chondrocytes are more likely to have more oxidative stress and more age related changes as a consequence so are less able to maintain the normal cartilage in these joints.
