Osteoarthritis Flashcards
What features would you use to describe an arthritis?
Joint affected
No of joints: mono/oligo/poly
Small or large joints/ proximal or distal
Symmetry
What is the normal function of articular cartilage?
- Reduce friction
- Distribute load
In terms of healing what are the properties of mature cartilage?
It is:
- Avascular
- Aneural
- Alymphatic
It therefore has no healing potential.
Note: immature cartilage has a stem cell population.
Where does mature cartilidge get its nutrients from?
Synovial fluid and blood from subchondral BM.
What limited healing process occurs in cartilage?
Acute damage may cause bleeding from the BM.
Blood may fill the defect and by 4 months this becomes fibrocartilage.
Note: much less structurally sound.
What symptoms do patients with OA get?
- Pain (initially activity related then permanently)
- Stiffness (morning but lasts <30m)
Later: muscle waisting, deformity, joint instability
Fluctuant symptoms waxing and waining
How can OA be categorised?
On severity of symptoms (mild/moderate/severe)
OR
Primary: Idiopathic
Secondary: caused by an underlying condition, such as a joint injury; accumulation of calcium inside the joint; other bone and joint conditions (eg, rheumatoid arthritis)
What are risk factors for developing osteoarthritis?
Age
Female
Obesity
Occupational stress on a joint
Sports stress on a joint (e.g runner on knees)
Previous trauma
Hypermobility
Family history
Weight lifting
Which joints are you most likely to suffer osteoarthritis?
Localised OA: Knee and hip
Generalised OA: Nodal (hands: MCP and CMJ thumb, DIP/PIP), Eroise OA
Can occur in any joint
In glenohumeral joint will present with pain and reduced range of movement both active and passively
A 54yo lady who has swelling in her hands in the DIP and PIP, progressive stiffness particularly in the morning and pain. What is the most likely diagnosis?
Nodal generalised OA.
A form of osteoarthritis usually seen in females, it has an autoimmune component and is characterised by nodules in the DIP (Hebden’s nodes) and PIP (Bouchard’s nodes).
On Xray what might findings might you find in a joint with osteoarthritis?
Joint space narrowing as articular cartilage wears down.
Osteophytes: bodies attempt at healing. Note only occur in OA not seen in RA or psoriatic arthritis.
Sclerosis: Bone’s response to increased weight as threes less load spreading with loss of cartilage
Cysts: A rare finding usually denoting more severe disease.
Note: Xray findings often do not correlate to severity of symptoms
What should be the medical management of osteoarthritis?
WHO pain ladder:
- Topical NSAIDS + paracetamol first line
- PO NSAIDS + capsoicin 2nd
Patient education and lifestyle modification
- weight loss
- stop wt bearing sports aka running, weight training at gym
- physiotherapy
- walking aids, splinting, insoles
Intrarticular steroid injections, does not improve progression but aids pain. (effect for <6w)
When is arthroplasty indicated?
Failure of conservative management.
Rest pain. Inability to perform ADL’s, LOF
Try to delay as long as possible as poor prognosis in young
Paediatric patients/paget’s disease/tumour.
Lastly consider factors such as:
- co-morbidities
- will quality of life improve (are they bedbound anyway)
- compliance of patients
Describe the pathophysiological changes which occur in primary OA?
Inflammation: inflammed synovium and thickened joint capscule > capsular fibrosis
Loss of cartilidge and ligament destruction
Synovial fluid: Increased water content, low viscosity, causing increased permeabiity, protein content falls and reduces overall compressive stength
Subchondral bone thickens
What is a CAM deformity?
A CAM deformity is when the femoral head is aspherical (happens in adolescence)
This causes there to be impingement with the margin of the acetabulum during flexion and internal rotation.
This will lead to the development of secondary OA and can often lead to limited internal rotation of the patients hip due to the defect.
What signs might you see in OA of the hip?
Atalgic gait.
Trendelenberg’s gait (if OA has resulted in abductor weakness)
Reduced leg length on effected side (reduced joint space)
Pain and limited ROM: internal and external rotation, adduction
What are the main types of hip prosthesis? (5)
Cemented Total Hip Replacement
Uncemented Total Hip Replacement
Hybrid (Cemented stem, uncemented acetabulum)
Reverse hybrid (Cemented acetabulum, uncemeneted stem)
Hip resurfacing (becoming less common as earlier failure rates)
What are the advantages and disadvantages of cementing?
Advantages:
- thought to be stronger than uncemented
- reduces the risk of intraoperative fracture
Disadvantages:
- longer procedure
- clinical trials don’t show a clear benefit
- can cause an initial hypotensive response therefore shouldn’t do in unstable patients
What are the risks of hip arthroplasty? (7)
Infection 0.5-1% (if occurs need joint aspirate to confirm, removal of prosthesis and long course of abx)
Neuromuscular damage (femoral or sciatic nn) rare less than 0.3% of patients.
Loosening of prosthesis
Dislocation (can be intraoperative or due to trauma)
Wear of prosthesis
Periprosthetic fracture
Persistent pain
Leg length discrepency
Describe what can be seen in the following image?
Joint space narrowing
Osteophyte
Maybe some cysts around neck
What OA features might you find on examination?
- Bony swellings
- Muscle waisting
- Joint line tenderness
- Effusion or crepitus
- Limited range of movements
- Hip: Ex+in rotation, adduction
- Deformity (e.g. knee varus)
- +ve trendelenburg test, antalgic gait (Hip)
Name some of the causes of secondary OA
- Pre-existing joint damage: (septic, gout etc), AVN, trauma
- Acromegaly, chondrocalcinosis, haemochromotosis
- Haemophilia, neuropathies
What is the surgical treatment of OA
Non arthoplastic surgery:
- Arthroplasty and wash
- Osteotomy (realign bones)
- Cheilectomy (remove spurs e.g. halux)
- Arthrodesis (fusion)
Arthroplasty:
- Hemi e.g. shoulder
- Total joint replacement e.g. knee
- Partial arthroplasty e.g. medial meniscus
What investigations would you send off for a patient presenting with potential OA
- X Ray: 2 views of the joint
- CRP/ESR/RF: rule out RA
- CT or MRI if X-ray not matching the clinical picture
