Musculoskeletal Pathophysiology - JOINTS

Question 1

What is a Joint?

Answer 1

A joint is where 2 or more bones meet

Question 2

What is the primary function of a joint?

Answer 2

To provide stability and mobility to the skeleton

Question 3

What are the 3 main joint types?

Answer 3

1. Synarthrosis
2. Amphiarthrosis
3. Diarthrosis

Question 4

Main points about Synarthrosis joints

Answer 4

• Formed when the gap bw 2 bones ossify and they become in effect, a single bone
• Immovable
• Fibrous

Question 5

Main points about Aphiarthrosis joints

Answer 5

• When 2 bones are linked by cartilage
• Slightly movable
• Cartilaginous

Question 6

Main points about Diarthrosis joints

Answer 6

• 2 bones are separated by a “joint cavity”
• aka Synovial
• Movable
• Most familiar type of joint
• Articular cartilage
• joint cavity
• Synovial fuid
• Joint capsule

Question 7

Types of Synovial Joints

Answer 7

Question 8

Movement

Answer 8

Question 9

Define dislocation

Answer 9

The displacement of a bone from its joint

Question 10

What do you do when a joint is dislocated?

Answer 10

• Joint must be restored to normal position, then joint immobilised for healing of torn ligaments and tendons

Question 11

Carpal bones

Answer 11

Question 12

What are four disorders of joints?

Answer 12

1. Osteoarthritis
2. Rheumatoid arthritis
3. (Ankylosing) Spondylitis
4. Metabolic joint disease e.g. gout

Question 13

What is Osteoarthritis?

Answer 13

Age related disorder of synovial joints

• “wear and tear” arthritis
• fingers, spine, hips, knees
• rare <40
• >85% in >70s
• overweight
• men>women <55
• can immobilise hips
• usually does not cripple

Question 14

Causes of osteoarthritis

Answer 14

• Trauma - strains, sprains, joint dislocations, fractures
• Long term mechanical stress - athletics, ballet, obesity
• Joint instability - due to damaged supporting ligaments, capsule or tendons
• Neurological disorders
• Conjenital or aquired skeletal deformities
• Hematologic or endocrine disorders - hemophilia, hyperthyroidism
• Obesity

Question 15

Pathophysiology of osteoarthritis

Answer 15

• Loss of articular cartilage
• Cartilage becomes thin → underlying bone unprotected
• Bone becomes sclerotic (dense and hard)
• Bone spurs can form and break off into synovial cavity → synovitis & joint effusion

Question 16

Clinical manifestations of osteoarthritis

Answer 16

• Pain
• Stiffness
• enlargment/sweling
• muscle wasting
• partial dislocation
• deformity
• use-related joint pain that is relieved by rest

Question 17

Diagnosis & treatment of osteoarthritis

Answer 17

Diagnosis

• Clinical assessment
• Radiological studies
• CT scan
• Arthroscopy
• MRI

Treatment

• Rest, motion exercies, crutches, weight loss, pain relief (analgesic) and anti-inflammatory medication
• Intra-articular injection of high MW viscosupplements (hyaluronic acid)
• Surgery - improve joint mvmnt, correct deformity/malignment, create new joint

Question 18

What is Rheumatoid Arthritis?

Answer 18

Systemic autoimmune disease associated with swelling and pain in multiple joints

More severe than osteorthritis

Body produces antibodies to fight infection → fails to recognise own tissues → misguided antibody “rheumatoid factor” attacks synovial membrane

Question 19

Rheumatoid arthritis: inflammatory autoimmune disease - Mechanism & what is ankylosis?

Answer 19

• Inflammatory cells accumulate in synovial fluid
• produce enzymes → degrade articular cartilage, fibrous joint capsule and surrounding tendoms
• as articular cartilage degrades → joints ossify
• joints solidly fuse & immobilized → ankylosis

Question 20

Rheumatoid arthritis: Clinical manifestation

Answer 20

• Disease tends to be symmetrical
  
  • if RHwrist, then LHwrist too
• Fever, malaise, rash, lymph node/spleen enlargment, Raynaud phenomenon (transient lack of circulation to fingers and toes)

Rheumatoid “hot spots” shown below:

Question 21

Rheumatoid arthritis: Incidence

Answer 21

• 1-2% adults (>30yrs)
• f:m = 3:1

Question 22

Rheumatoid arthritis: Diagnosis & treatment

Answer 22

Diagnosis:

• Physical examination
• Xray of joint
• Serological tests for RF & circulating immunr complrxities
• Diagnosis criteria (requires 4+)
  
  • Morning stifness >1hour
  • Arthritis >3 joint areas
  • Arthritis of hand joints
  • Symmetric arthritis
  • Rheumatoid nodules
  • Abnormal levels of serum RF present
  • Radiographic changes

Treatment

• Rest, hot/cold packs, physical therapy
• Antineoplastic medicaton, anti-inflam drugs, immunosuppressants, disease modifying antirheumatic drugs, corticosteroids
• ↑calorie and vitamin diet
• Surgical syneovectomy (early disease)
  
  • correct deformality/mechanical resistance
• Arthroplasty/joint relplacement (late disease)

Question 23

What is Ankylosing Spondylitis?

Answer 23

The stiffening and fusion (ankylosis) of the spine and sacroiliac joints

• An inflammatory joint disease
• m:f = 3:1
• Begins late adolecence/early adulthood (peak at ~20)

Question 24

How can you clinically diagnose Ankylosing spondylitis?

Answer 24

• Low back pain/stiffness worse after prolonged rest
• Pain eases with activity
• Normal convex curve of lower back diminishes
• Concavity of the upper spine increases
• Thoratic-spine becomes rounded
• Head and neck helf forward on shoulders
• Hips are flexed
• Pleuritic chest pain
• Restricted chest movement
• Pelvic tenderness
• Tenderness in heals
• Unable to sit on hard surfaces
• Fibrotic changes in lungs
• Cardiomegaly
• Aortic incompetence
• Amyloidosid
• Achilles tendinitis
• Fatigue
• Weight loss
• Low-grade fever
• Hypochronic anemia

Question 25

Ankylosing spondylitis: Evaluation and treatment

Answer 25

Evaluation/diagnosis:

• History & physical examination
• X-ray
• MRI
• Serum analysis (HLA-B₂₇)
• Erythrocyte sedimentation
• ↑ alikaline phosphatase

Treatment:

• Physical therapy to maintain skeletal mobility
• NSAIDs
• Analgesic medication (supress pain and stiffness)
• Symptom relief

Question 26

What is Gout?

Answer 26

• A syndrome caused by an inflammatory response to uric acid production or excretion - hyperuricemia*
• Leads to increased uric acid in synovial joint

Question 27

Gout: Risk factors

Answer 27

• Age
• Genetic predisposition
• Excessive alcohol
• Obesity
• Certain drugs (e.g. thiazides)
• Lead toxicity

Question 28

Pathophysiology of Gout

Answer 28

• Most uric acid (protein metabolism) eliminated from body via kidneys
• Crystalization in synovial tissue
  
  • Lower body temperatures → ↓solubility
  • Changes in pH → ↓solubility
  • Trauma → ↑crystal pptn
• Leads to inflammatory response in the joints → tissue damage

Question 29

What is the incidence/time of onset of gout?

Answer 29

• Rare in children, premenopausal women, and men <30
• Males peak at ~40-50 yrs
• Females, later than M

Question 30

Clinical manifestations/symptoms of Gouts

Answer 30

• ↑ serum uric acid conc.
• recurrent monoarticular arthritis attacks
• urate crystal deposits around joint
• renal disease → renal stones
• trauma is aggrevating
• abrupt attacks
• primary symptom: severe pain, night, affected area hot, red, tender, swollen
• 50% initial attacks in metatarsalophalangeal joint
• 50% elbow, heel, ankle, knee, wrist

Question 31

How would you treat gout?

Answer 31

• Antiinflammatory drugs
• NSAIDs
• Xanthine oxidase inhibitors
  
  • allopurinol
  • febuxostat
• Ice may relieve pain
• Hydrocortisone injection at joint
• Antihyperuricemeid drugs
• Low protein diet

Question 32

What is Arthroplasty?

Answer 32

The replacement of diseased joint with artificial device called prosthesis

Avaliable for:

• finger
• shoulder
• elbow
• hip
• knee