Osteoarthritis

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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.

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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

Abnormal anatomy leads

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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

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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.

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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

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Differential Diagnosis

 

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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

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

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

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Consequences and Course

 

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Resources and References

 

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Topic Development

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