Joints and Joint Problems Flashcards
What are the three types of joints?
Fibrous; bones connective with fibrous connective tissue (collagen fibres)
Cartilaginous; bones connected by cartilage
Synovial; joints articulating with synovial fluid
What are some fibrous joints?
- Periodontal ligament
- Cranial sutures
- Interosseus membranes (i.e. between radius and ulna)
What makes up a primary cartilaginous joint?
Only hyaline cartilage
i.e. synchondrosis (almost immovable between bones)
What makes up a secondary cartilaginous joint?
Hyaline and fibrocartilage
i.e. symphysis intervertebrqal disc
What are common features of a synovial joint?
- Synovial cavity (fluid-filled)
- Articular cartilage
- Fibrous capsule
- Synovial membrane
May also have
- articular discs
- ligaments
- bursae
What are the subtypes of synovial joints?
- plane
- condylar (ellipsoid)
- hinge
- saddle
- pivot
- ball and socket
Describe the arrangement of articular cartilage (hyaline)
Superficial/tangential layer; flattened chondrocytes that produce collagen and glycoproteins
Transitional layer; round chondrocytes that produce proteoglycans such as aggrecan
There is a change in collagen orientation from superficial to deep layers
> 75% water
What layer of articular cartilage produces collagen and glycopreoteins?
Superficial layer
Produced by the flattened chondrocytes
What layer of articular cartilage produces proteoglycans i.e. aggrecan?
Transitional layer
Produced by round chondrocytes
What are glycoproteins?
e.g. lubricin
Proteins to which oligosaccharide chains are attached
i.e. more protein than carbohydrate
What are proteoglycans?
e.g. aggrecan
Proteins that are heavily glycosylated (+ a protein core to which one or more GAGs attach)
i.e. more carb than protein
What are glycosaminoglycans (GAGs)?
e.g. hyaluronic acid
Long unbranched polysaccharides, highly polar and thus attract water
What is the general thicknesses of articular cartilage?
Average; 2-3mm
Interphalangeal joint; 1mm
Patella; 5-6mm
Describe the synovium
Synovial membrane which produces the synovial fluid
Synoviocytes produce the fluid
Rich capillary network
No epithelial lining
Direct exchange of oxygen, CO2, metabolites between blood and synovial fluid
Describe type A synoviocytes
Look like macrophages
Remove debris
Contribute to synovial fluid production
Describe type B synvoviocytes
Fibroblast like
Main producer of synovial fluid
Describe synovial fluid
Viscous fluid, hyaluronic acid and lubricin, fluid component form blood plasma
Small volumes; knee joint ).5ml)
Rapid turnover ~2hours
What are the functions fo synovial fluid?
Nutrition of cartilage (articular c, menisci/discs)
Removal of waste products
Lubrication - less friction - less wear
Describe joint lubrication
Boundary; glycoproteins i.e. lubricin bind to receptors on articular surfaces to form thin film
Hydrodynamic; surfaces kept apart by liquid pressure, viscosity changes with load and velocity of movement
Weeping; fluid that is present in cartilage squeezed out into synovial cavity to increase fluid vol
Describe the effect of ageing on joints
Viscosity of synovial fluid increases; slower joint movement and reduced lubrication
Water content of cartilage decreases; reduced shock absorption
These cause less protection of articular surfaces and increased risk of damage
Describe the pathologenesis of osteoarthritis
Trauma and mechanical imbalance
Inflammation and pain
Repair processes around the joint
How is osteoarthritis diagnosed?
45+ years
Activity related joint pain + either no morning joint stiffness or morning stiffness lasting no longer than 30mins
ATTENTION! Trauma, prolonged morning-related stiffness, rapid deterioration of symptoms, hot swollen joint
What are possible differential diagnoses in osteoarthritis?
- gout
- other inflammatory arthritis
- septic arthritis
- malignancy
What is the investigation for suspected OA?
Generally X-Ray to confirm clinical diagnosis
Describe the management of OA
Non-pharmacological
- thermotherapy
- electrotherapy
- aids and devices
- manual therapy
- NICE don’t recommend acupunture, nutraceuticals
Pharmacological
- oral; paracetamol, NSAIDs
- topicals; NSAIDs, capsaicin
- intra-articular injection; steroid
Surgery if substantial impact on QoL
How are hip fractures classified?
Intracapsular
- edge of femoral head to capsule of hip joint
Extracapsular
- trochanteric/subtrochanteric (lesser trochanter is division line)
GARDEN system is one classification method
Describe the treatment of an undisplaced intracapsular hip fracture
Internal fixation or hemiarthroplasty if unfit
Describe treatment of a displaced intracapsular hip fracture
young and fit i.e. <70yrs : reduction and internal fixation
Older and reduced mobility: Hemiarthroplasty or total hip replacement if fit
Describe treatment of an extracapsular hip fracture
dynamic hip screw
If reverse oblique, transverse or subtrochanteric : intramedullary device
