Musculoskeletal and Rheumatology Flashcards
What are the 2 types of bone at a macro level?
Cortical:
* Compact
* Dense, solid
* Only spaces are for cells and blood vessels
Trabecular:
* Cancellous (spongy)
* Network of bony struts (TRABECULAE)
* Looks like sponge, many holes filled with bone marrow
* Cells reside in trabeculae and blood vessels in holes
What are the different types of bone at a micro level?
Woven bone:
* Made quickly
* Disorganised
* No clear structure
Lamellar bone:
* Made slowly
* Organised
* Layered structure
What is the function of hollow long bones?
Keeps mass AWAY from the neutral axis and minimised deformation
What is the function of Trabecular bone?
Give structural support while minimising mass
What is the function of bone that has wide ends?
Spreads load over weak, low friction surface
What is the composition of bone in adults?
- 50-70% mineral:
- Hydroxyapatite - crystalline form of calcium phosphate
- 20-40% organic matrix:
- Type 1 Collagen - 90% of all protein
- Non-collagenous proteins - 10% of all protein
- 5-10% water
What do the minerals and collagen provide to bone respectively?
Minerals - Stiffness
Collagen - Elasticity
What is the function of a joint?
- Allow movement in 3 dimensions
- To bear weight
- To transfer the load evenly to the musculoskeletal system
Give some key joints and examples
- Fibrous - teeth sockets
- Cartilaginous - intervertebral discs
- Synovial - metacarpophalangeal and knee joint:
What are the main features of a synovial joint?
- Articular cartilage
- Joint capsule - the inner layer is the
synovial membrane - Joint (synovial) cavity - space filled with synovial fluid
- Synovial fluid
- Reinforcing ligaments
+Bursae and Menisci
What is the function of Synovial Fluid?
Lubrication
Shock absorption
Nutrient Distribution
What is ESR?
Erythrocyte Sedimentation
An Inflammatory marker That rises with inflammation and infection.
ESR rises and falls slowly
What is CRP?
C-Reactive Protein
Acute phase marker of inflammation and infection.
Produced by the liver in response to IL-6
Rises and falls rapidly (acute inflammation CRP rises but ESR takes longer)
Define Osteoarthritis
A non-inflammatory degenerative joint disorder characterised by joint pain and functional limitation.
Osteoarthritis is an age-related, dynamic reaction pattern of a joint in response to insult or injury (Wear and Tear)
All tissues of the joint are involved
Articular cartilage is the most affected – produced by chondrocytes
What is the pathophysiology of OA?
Imbalance in process of cartilage breakdown by wear and tear and by chondrocytes releasing cartilage breakdown Factors leading to erosion of the articular cartilage in synovial joints.
- Faulty cartilage undergoes erosion
- disordered repair
- fibrillations occur
- cartilage ulceration which exposes underlying bone to increased stress
- microfractures and cysts
exposed bone attempts repair - abnormal sclerotic subchondral bone and overgrowth at joint margins (osteophytes)
What are the main features in the pathology of OA?
Loss of cartilage through wear and tear
Disordered bone repair
What controls the development of OA?
Mediated by cytokines:
IL-1, TNFa, NO
Driven By mechanical Forces
What is the epidemiology of OA?
Most common type of arthritis
Especially in elderly and females
Most common condition affecting synovial joints
Most important condition relating to disability as a result of locomotor symptoms
8.75 million people in the UK seek treatment for OA
What are the non-modifiable risk factors for OA?
Genetics -COL2A1 has a role
Increasing Age - strongest RF
Female - Hip OA 2x more common
High bone density - protective against osteoporosis but RF for OA
What are the modifiable Risk factors for OA?
Obesity
Joint injury/damage
Exercise stress
What are the symptoms of OA?
Joint pain - exacerbated by movement and relieved by rest
Worse as the day goes on
Joint Stiffness
Crepitus
Swelling
Joint Locking - inability to straighten joints
What is the typical Presentation of OA?
Elderly Px with knee/hip pain.
Morning stiffness lasting less that 30 mins
Pain increases with use (crepitus) and during the day
Asymmetrical joint involvement.
Bony swellings DIP/PIP
What are the clinical signs of OA?
Hands:
Bouchard’s Nodes (PIPJ)
Heberden’s Nodes (DIPJ)
Thenar Muscle wasting
First CMC Joint affected most
Knees:
Crepitus
Hips:
Antalgic gait
Restricted internal rotation
All affected Joints:
Joint tenderness
What is Heberden’s and Bouchard’s Nodes?
What condition are they seen in?
Seen in OA.
Bouchard’s - Bony swelling at PIP
Heberden’s - Bony swelling at the DIP
Remember B before H and proximal before distal