Arthroplasty: Osteoarthritis, Rheumatoid Arthritis And Avascular Necrosis. Flashcards
Define Osteoarthritis
Osteoarthritis is a disabling joint disease characterized by degeneration if the joint complex (articular cartilage, subchondral bone, and synovium). It has multiple causes.
Discuss the etiology of Osteoarthritis.
Characterized into modifiable and non-modifiable.
Modifiable:
1. Obesity
2. Overuse of joint
Non-modifiable:
1. Age(>55 years)
2. History of joint injury, trauma and/or surgery.
Discuss the epidemiology of osteoarthritis
Prevalence: most common joint disorder
Incidence: Increases with age
Sex: Females>Males
Incidence rates: Knee>Hip>Hand
Describe the pathophysiology of Osteoarthritis.
- Cartilage: Enzymatic degradation and loss.
- Synovium: Inflammation, vascular hypertrophy
- Ligaments: Tighten on concave side of deformity.
- Bone: Sclerosis, Osteophytes, and subchodral cysts
- Muscles: Atrophy from inactivity.
Define Avascular necrosis
Death or decay of tissue due to local ischemia IN ABSENCE OF INFXN
Also known as osteonecrosis or aseptic necrosis.
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Describe the pathophysiology of rheumatoid arthritis
• T cell mediated immune response
•a Genetic component (HLA-DR4 and HLA-DR1)
• Delayed inflammatory response
• The initial response on soft tissues- neovascularization and synovitis.
• intimal lining hyperplasia with mononuclear WBCs.
•Both synoviocytes will produce cytokines.
Type A, Macrophages: main source for TNF-Alpha and IL-1
Type B, Fibroblast: main source for MMP, proteases and RANKL
•B lymphocytes make RF and anti-CCP antibodies
Cytokines upregulated: TNF-Alpha, IL-1, IL-6 and IL-7.
Describe the pathophysiology of Avascular necrosis
There’s arteriolar occlusion that leads to marrow oedema, leading to sinusoidal compression, which leads to vascular stasis.
Sickle cell disease and thrombocytopenia can lead to arteriolar occlusion.
Which regions are more prone to AVN after injury?
Head of femur
Lunate
Head of humerus
Proximal pole of scaphoid.
Describe the risk factors for Avascular Necrosis
It is more prevalent in males.
Average age: 35 to 50 y/o.
Risk factors that increase clinical suspicion= PLASTIC RAGS
Pancreas
Lupus
Alcohol
Steroids
Trauma
Idiopathic
Collagen vascular disease
Radiation/RVD
Amyloidosis/ARV-Protease Inhibitors
Gaucher’s disease
Sickle Cell Disease
Describe your findings of LOOK, FEEL, MOVE on Osteoarthritis
[LOOK]
1. Larger joints may be swollen
2. Abnormalities in GAIT.
3. Deformities of the joint=Genu Varum.
[FEEL]
1. May be an effusion
2. Tender - specifically joint line, e.g. for hip, tender in groin.
[MOVE]
1. Crepitus felt with ROM
2. ROM reduced
3. Instability of joint in some directions due to attenuation of soft tissue envelopes.
Describe your LOOK, FEEL, MOVE on Rheumatoid Arthritis.
[LOOK]
1. More common in smaller joints
2. May be gross deformity, especially in advanced disease.
[FEEL]
1. Subcutaneous nodules
[MOVE]
1. Grossly deformed jointd may be sublaxed
2. Decrease in ROM
3. Instability of joints.
Describe your LOOK, FEEL, MOVE for Avascular Necrosis
[LOOK]
1. Mild non-specific swelling
2. Gait changes similar to OA if hips affected.
3. Deformity so similar to OA.
[FEEL]
1. Joint line tenderness
[MOVE]
1. Similar to OA
Investigations for OA, RA, and AVN
[SEROLOGY]
•Serology isn’t very useful for these pathologies, except in RA where RF and ACCP can be used for confirmation of disease.
• In AVN, maybe you can test for amylase increase for Pancreatisis.
• Serology may be used to exclude infection or Malignancy.
Describe the radiology findings in Osteoarthrits.
Joint space narrowing. Subchondral cysts.
Osteophytes.
Sclerosis.
Describe radiology findings for Rheumatoid Arthritis
Joint space narrowing
Periarticular erosions
Periarticular osteopaenia
🫡Soft tissue swelling may be observed.
Describe radiological findings in AVN
Cyst formation
Subchondral collapse
Head flattening and collapse-Destruction.
Describe the treatment for Osteoarthritis
[Non pharmacological]
1. Exercise
2. Weightloss
[Pharmacotherapy]
1. NSAIDS
2. Intraarticular glucocorticoid injections
[Surgical]
1. Completely partial joint replacement (Arthroplasty) using an Endoprosthesis Physical Therapy
Describe clinical features of Osteoarthritis
- Pain during or after exertion that is relieved with rest
- Morning joint stiffness lasting less than 30 minutes
- Joints are asymetrically involved.
Joint specific finding:
Heberden nodes: found on DIPs
Bouchard nodes: found on PIPs.
In contrast to Rheumatoid Arthritis, Osteoarthritis can affect the Distal Interphalangeal Joints
Briefly discuss the surgical options of treating Osteoarthritis.
- 5 provides short-term relief
- Osteotomy - the bone is cut and reshaped to shift away the weight from the damaged area, reducing joint stress.
- Arthrodesis(Joint Fusion)- for small joints, the affected joint is permanently fused, eliminating movement but reducing pain.
Describe the pathology of Avascular Necrosis
Dead bone is structurally and radiographically indistinguishable from live bone. But, lacking perfusion, it doesn’t undergo renewal, and after a limited period of repetitive stress, it collapses.
Changes develop over these 4 overlapping stages
1. Stage 1: Bone death without structural change
2. Stage 2: Repair and early structural failure.
3. Stage 3: Major structural failure
4. Stage 4: Articular destruction.
Describe the staging system for Osteonecrosis.
[Modified ARCO staging of Osteonecrosis]
Stage 0: The patient is asymptomatic, and all clinical investigations are normal.
Stage 1: X rays are normal. MRI shows osteonecrosis.
Stage 2: Xrays and MRI show early signs of osteonecrosis but no distortion of bone shape.
Stage 3: Xray shows early abnormality but femoral head is still spherical
Stage 4: Signs if flattening or collapse of femoral head
Stage 5: plus loss of joint space
Stage 6: plus marked destruction of articular surfaces.
