Musculoskeletal Pathophysiology - JOINTS Flashcards
What is a Joint?
A joint is where 2 or more bones meet
What is the primary function of a joint?
To provide stability and mobility to the skeleton
What are the 3 main joint types?
- Synarthrosis
- Amphiarthrosis
- Diarthrosis
Main points about Synarthrosis joints
- Formed when the gap bw 2 bones ossify and they become in effect, a single bone
- Immovable
- Fibrous
Main points about Aphiarthrosis joints
- When 2 bones are linked by cartilage
- Slightly movable
- Cartilaginous
Main points about Diarthrosis joints
- 2 bones are separated by a “joint cavity”
- aka Synovial
- Movable
- Most familiar type of joint
- Articular cartilage
- joint cavity
- Synovial fuid
- Joint capsule
Types of Synovial Joints
Movement
Define dislocation
The displacement of a bone from its joint
What do you do when a joint is dislocated?
- Joint must be restored to normal position, then joint immobilised for healing of torn ligaments and tendons
Carpal bones
What are four disorders of joints?
- Osteoarthritis
- Rheumatoid arthritis
- (Ankylosing) Spondylitis
- Metabolic joint disease e.g. gout
What is Osteoarthritis?
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
Causes of osteoarthritis
- 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
Pathophysiology of osteoarthritis
- 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
Clinical manifestations of osteoarthritis
- Pain
- Stiffness
- enlargment/sweling
- muscle wasting
- partial dislocation
- deformity
- use-related joint pain that is relieved by rest
Diagnosis & treatment of osteoarthritis
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
What is Rheumatoid Arthritis?
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
Rheumatoid arthritis: inflammatory autoimmune disease - Mechanism & what is ankylosis?
- 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
Rheumatoid arthritis: Clinical manifestation
- 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:
Rheumatoid arthritis: Incidence
- 1-2% adults (>30yrs)
- f:m = 3:1
Rheumatoid arthritis: Diagnosis & treatment
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)
What is Ankylosing Spondylitis?
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)
How can you clinically diagnose Ankylosing spondylitis?
- 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
Ankylosing spondylitis: Evaluation and treatment
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
What is Gout?
- A syndrome caused by an inflammatory response to uric acid production or excretion - hyperuricemia*
- Leads to increased uric acid in synovial joint
Gout: Risk factors
- Age
- Genetic predisposition
- Excessive alcohol
- Obesity
- Certain drugs (e.g. thiazides)
- Lead toxicity
Pathophysiology of Gout
- 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
What is the incidence/time of onset of gout?
- Rare in children, premenopausal women, and men <30
- Males peak at ~40-50 yrs
- Females, later than M
Clinical manifestations/symptoms of Gouts
- ↑ 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
How would you treat gout?
- Antiinflammatory drugs
- NSAIDs
- Xanthine oxidase inhibitors
- allopurinol
- febuxostat
- Ice may relieve pain
- Hydrocortisone injection at joint
- Antihyperuricemeid drugs
- Low protein diet
What is Arthroplasty?
The replacement of diseased joint with artificial device called prosthesis
Avaliable for:
- finger
- shoulder
- elbow
- hip
- knee
