Osteoarthritis
last authored:
last reviewed:
Introduction
Osteoarthritis, a degenerative disease, is the most common form of arthritis in primary care. many people with OA have no symptoms, buit it can also very much interfere with QoL.
Nova Scotia has the highest self-report of arthritis in Canada (over 20%)
Arthritis prevalence, approximately 10-12%, is tending to go up 1% every 5 years.
Almost everyone over the age of 65 shows signs of OA on X-ray, but only 1/3 of these people are symptomatic.
Get drawing of joints affected by OA.
The Case of...
a simple case introducing clincial presentation and calling for a differential diagnosis to get students thinking.
Causes and Risk Factors
OA is by far the common form of arthritis.
Age related. Frequency is similar in males and females until age 55, then rates in females is much higher.
50% of people over 65 have X-ray evidence of OA in the knee, and virtually everyone over 75 does
Risk factors
- obesity
- trauma
- congenital deformities - leg length discrepancies, etc
- occupation
- inflammatory arthritis
- metabolic disorders
- family history - knobby knuckles can be transmitted in autosomal dominant patterns
Abnormal anatomy leads
Pathophysiology
OA is primarily a problem with articular cartilage.
Bony outgrowths (osteophytes) grow alongside the joint and under the joint.
Can get eburnation - smooth denuded bone ends
subchondral cysts
ligaments can have decreased motion and strength
Hip - hip abductors contract to stabilize hip, causing torque and pain.
Knee
medial side is mosr common, with loss of joint space causing varus.
can get hallux valgus
patellofemoral osteoarthritis can occur as a combination of increased Q angle and repetitive microtrauma
Signs and Symptoms
- history
- physical exam
History
The most common joints affected are hip and knee, though distal hands and spine are also often involved.
Pain with weight bearing improves with rest.
Morning stiffness under 30 minutes, as opposed to RA.
Physical Exam
crepitus
not very much warmth in joints
Swollen joints are hard and bony to touch.
Hands
can get Heberden's nodes in the DIPs and Bouchard's nodes in the PIP in primary generalized osteoarthritis
Feet
Spine
especially in lower lumbar region
scoliosis, with more pronounced osteophytes on the concave (compression) side
The Trendellenburg gait can occur as people throw their weight over the affected hip.
Investigations
- lab investigations
- diagnostic imaging
Lab Investigations
There are no lab tests that are useful for diagnosing OA.
Diagnostic Imaging
On X-ray, features to look for include:
- joint space narrowing
- subchondral sclerosis
- subchondral cyst formation
- osteophytes
Differential Diagnosis
Treatments
The goals of management are to releive pain, reserve joint motion and function, and prevent further injury.
Non-pharmacological
Patient education, weight loss, exercise, and assistive devices can are all useful.
A cane, two canes, or a walker will unload the hip or leg. The cane should preferentially be held in the opposite arm to increase the lever arm distance. Knee braces or food orthosis can be used to unweight the knee.
Medications
Consider co-morbid conditions and avoid medication interactions.
Analgesics, ie acetominophen (325-1000mg qid prn), are the first-line. OA is not inflammatory.
NSAIDs: ibuprophen, naproxen
- Cox-2 selective NSAIDs, ie Celebrex, recommended for long-term therapy or in situations of high risk for GI effects.
DMARDs: methotrexate, gold, plaquinenil
Topical NASIDs such as Pennaid, or capsaicin cream, such as Zostrix, can be used.
Glucosamine sulfate 1500 mg daily has been shown to improve pain scores and decrease joint space.
Injections
corticosteroids - target phospholipases, preventing arachidonic acid formation
- use caution with tendons or infections; limit to 4 injections per joint per year.
The effects of injections typically last 4-6 weeks, though can still be of benefit up to 6 months later.
artificial joint lubricants - hyaluronic acid
aspiration
Surgery
osteotomy
arthroscopy
ankle arthrodesis, fusion, arthroplasty, or replacement
hip replacement can be a very successful
Consequences and Course
Resources and References
Topic Development
authors:
reviewers:
 |