OA and osteonecrosis Flashcards
What is osteoarthritis?
Osteoarthritis (OA) is a clinical syndrome of joint pain accompanied by varying degrees of functional limitation and reduced quality of life.
What are the most commonly affected joints in OA?
It is the most common form of arthritis and one of the leading causes of pain and disability worldwide. The most commonly affected peripheral joints are the knees, hips and small joints of the hands.
What is the pathophysiology of OA?
Osteoarthritis (OA) is the result of mechanical and biological events that destabilise the normal process of degradation and synthesis of articular cartilage chondrocytes, extracellular matrix, and subchondral bone.
It involves the entire joint, including the articular cartilage, subchondral bone, pericapsular muscles, capsule, and synovium.
The condition leads to loss of cartilage, sclerosis and eburnation of the subchondral bone, osteophytes, and subchondral cysts.
It is clinically characterised by joint pain, stiffness, and functional limitation.
What are the secondary causes of OA?
Metabolic causes such as gout, pseudogout, acromegaly, Wilson’s disease, haemoglobinopathies, collagenopathies and hemochromatosis.
Traumatic causes such as joint injury, surgeries, fractures through a joint or osteonecrosis.
Anatomical causes such as slipped femoral epiphysis, Perthe’s disease, DDH and unequal leg lengths.
Neuropathic causes such as diabetes and syphillis.
IA causes
What are the risk factors for OA?
Age >50 years. Female sex Obesity High bone density- RF for development of OA Low bone density- RF for progression of knee and hip OA. Genetic factors Knee malalignment Physically demanding occupation/sport Joint injury and laxity
When can the diagnosis of OA be made clinically?
A diagnosis of OA can be made clinically without investigations if a person:
Is aged 45 years or over; and
Has activity related joint pain; and
Has either no morning joint-related stiffness or morning stiffness that lasts no longer than 30 minutes.
How does OA present?
OA-related pain is usually associated with activities, with pain in weight-bearing joints being associated with weight-bearing activities. Pain at rest or at night is unusual, except in advanced OA.
Knee pain due to OA is usually bilateral and felt in and around the knee
Hip pain due to OA is felt in the groin and anterior or lateral thigh. Hip OA pain can also be referred to the knee and, in males, to the testicle on the affected side.
Reduced function and participation restriction.
Functional difficulties, such as a knee giving way or locking, can be present. This can reflect an internal derangement, such as a partial meniscal tear or a loose body within the joint.
Commonly involved joints are the knee, hip, hands, and lumbar and cervical spine.
Both active and passive range of joint movement is reduced in moderate to advanced OA, and this is usually associated with pain.
OA can cause local tenderness over the joint line.
What are the signs of OA?
Reduced range of joint movement.
Pain on movement of the joint or at extremes of joint movement.
Joint swelling/synovitis (warmth, effusion, synovial thickening).
Periarticular tenderness.
Crepitus.
Absence of systemic features such as fever or rash.
Bony swelling and deformity due to osteophytes - in the fingers this presents as swelling at the distal interphalangeal joints (Heberden’s nodes) or swelling at the proximal interphalangeal joints (Bouchard’s nodes).
Joint instability
Muscle weakness/wasting around the affected joint
What are the investigations for OA?
X-ray of affected joints: New bone formation (osteophytes), joint space narrowing, and subchondral sclerosis and cysts.
Serum CRP and ESR: Needed if inflammatory arthritis is a possible differential. Usually normal range.
Body weight and body mass index: should be recorded.
MRI: may be useful to distinguish other causes of joint pain.
Blood tests: are normal in OA. Consider checking baseline FBC, creatinine and LFTs before starting a patient on non-steroidal anti-inflammatory drugs (NSAIDs).
Joint aspiration: may be considered for swollen joints to exclude other causes such as septic arthritis and gout.
What are the differentials of OA?
Pseudogout Bursitis Psoriatic arthritis Septic arthritis Reactive arthritis Gout Connective tissue disease Ankylosing spondylitis
What is the management of OA?
Holistic approach and self-management:
- Assess the effect of OA on patient’s lifestyle.
- Pain assessment
- Agree a plan with the person.
- Take into account comorbidities that compound the effect of OA.
- Promote activity and exercise.
- Interventions to achieve weight loss if the patient is overweight.
An annual review should be considered for any person with one or more of the following:
- Troublesome joint pain.
- More than one joint with symptoms.
- More than one comorbidity.
- Taking regular medication for OA.
Analgesics
- Paracetamol.
- Topical NSAIDs ahead of oral NSAIDs.
- Intra-articular injections- adjunct to treatment for relief of moderate to severe pain.
Minimally invasive and non-invasive therapies
- Thermotherapy
- TENS
- Walking sticks
- Bracing/joint supports for joint pain and instability
Surgery – joint replacement (patient must be offered all non-surgical options)
- Patient who are refractory to medical management.
- Substantial impact on the quality of life.
What are the complications of OA?
Functional decline and inability to perform activities of daily living.
Spinal stenosis in cervical and lumbar OA
NSAID-related GI bleeding
Effusion of the joint
NSAID-related renal dysfunction
What is the prognosis of OA?
Osteoarthritis is not always progressive and does not inevitably lead to increasing pain and functional impairment:
- Hand involvement has a good prognosis. Interphalangeal joint involvement usually becomes asymptomatic after a few years. Osteoarthritis of the first carpometacarpal (CMC) joint has a poorer prognosis.
- Hip involvement has a poorer prognosis than hand or knee. A significant proportion of people require hip replacement within five years of diagnosis.
- Knee involvement has a variable prognosis. Symptoms may improve spontaneously, remain stable, or progressively worsen, with structural changes on X-ray, which eventually require joint surgery.
What is the prevention of OA?
Weight control
Increasing physical activity
Avoiding injury
What is osteonecrosis?
This is a disease resulting in the death of bone cells.
Exact cause is unknown.
