Lecture 16: Joints and Joint tissues

Question 1

Describe the 4 phases of bone repair after a facture

Answer 1

1. Reactive phase: formation of fracture hematoma (solid swelling of clotted blood within tissues)
2. Reparative phase: fibrocartilaginous callus formation
3. Reparative phase: bony callus formation -(like endochondral ossification)
4. Bone remodelling phase- can make the healed fracture site even stronger

Question 2

Describe the time scale for the 4 phases

Answer 2

1. hematoma is immediate
2. fibrocartilaginous phase is 5 weeks later
3. bony callus formation is weeks to months
4. bone remodelling = 1 year

Question 3

How do metal plates and screws help bone fracture healing and which age group are they mostly used in

Answer 3

Metal plates and screws help to alignment fractured bone and prevent bone callus formation, however when they are removed the fracture is weaker and it takes longer to heal

Question 4

Compare fibrous, cartilaginous and synovial joints range of movement and their make up

Answer 4

Fibrous joints are bones held together by fibrous connective tissue. They have are simple and are most stable; immovable

Cartilaginous joints are bones that articulate by hyaline or fibro cartilage so there is minimal movment but still no gaps

Synovial joints are bones articulating with cartilage in a synovial cavity containing fluid covered by a joint capsule. It has a large range of movement due to space between bones but is also weakest

Question 5

What are the structural classification of joints vs the functional classification of joints

Answer 5

The structural classification is how its physically made: fibrous, cartilaginous and synovial, while the functional classification is in relation to the degree of movement permitted

Question 6

What are 3 functional classifications of joints

Answer 6

Synarthrosis : immoveable

Amphiarthrosis: slightly movable

Diarthrosis: freely moveable synovial joints

Question 7

What is eg of fibrous joint

Answer 7

Suture - in skull, interlocking using the shape of the bones or
Interosseous membrane: using woven fibres

Question 8

What is an eg of cartilagenous articulation

Answer 8

Intervertebral articulations- have a a cartilage endplate before the invertebral disc

Question 9

What is articular cartilage made of and what is its function

Answer 9

Specialised hyaline cartilage (avascular) which protects bones, provides smooth surface for joint articulation and distributes stresses across the joint

Question 10

Describe the two components of the joint capsule

Answer 10

Outer fibrous capsule made of tough layer of collagen fibres which stops over extension of the joint. It has nerves and bv

The inner synovial membrane secretes synovial fluid and lines the joint capsule right before the cartilage

Question 11

What causes rheumatoid arthritis

Answer 11

Swelling of the inflammed synovial membrane

Question 12

what is synovial fluid made of and function

Answer 12

It is an ultrafiltrate of blood plasma which acts as a source of nutrition for articular cartilage, lubrication for all articulating surfaces, heat dissipator and load distributor

Question 13

How does osteoarthritis happen

Answer 13

Through repetitive joint use or damage, the water content of cartilage increases and the protein components such as collagen starts to break down.
This irritates and inflames the cartilage causing joint pain and swelling. Advanced cases have loss of cartilage cushion causing pain and limited joint mobility.

Question 14

What are some tell tale changes of an osteoarthritic joint

Answer 14

• Bone remodelling and sclerosis (abnormal hardening)
• Osteophytes- abnormal projections of bone
• Synovial hypertrophy
• Cartilage break down (in knee alsomeniscal damage)

Question 15

What is the management and treatment of knee Osteoarthritis

Answer 15

NonSteroidAntiInflamDrugs (NSAIDS)/ pain relief
Weight management, cortisone injections in the joint
Exercise
Cartilage repair techniques like microfracture, mosaicplasty and autologous matrix induced chondrogenesis
Arthoplasty (knee replacement)

Question 16

What are therapies not recommended to treat OA

Answer 16

viscosupplementation (injections of lubricants into the joints) and Joint supplements

Question 17

What causes Gout

Answer 17

Due to high levels of uric acid in blood. Monosodium urate crystals are deposited in the joint causing an acute attack of inflammatory arthritis.

Question 18

What is the characterisation of tophaceous gout

Answer 18

Final clinical phase of gout, has tophi- collections of MSU crystals damaging joints and causing some bone erosion

Question 19

How is Gout managed

Answer 19

• Low purine diet
• avoidance of alcohol and fructose drinks
• Acute inflammatory treatment (colchicine) and long term urate lowering drugs like allopurinol

Question 20

What are menisci

Answer 20

fibrocartilage pads for the knee to stabilise the joint

Question 21

What are bursa and what can overuse of them cause

Answer 21

The are infolds of the joint cavity that can become inflammed with overuse

Question 22

Who is more likely to get gout

Answer 22

Men, and women after menopause. Maori and pasifika have high rates of early onset and severity

Question 23

What is the causes and risk factors for OA

Answer 23

no known cause but increased risk wiht age, obesity, genetics, gait cycle, occupation and injury

Question 24

In young spinal segment why is it hard to tell apart the cartilage end plates which ‘cap’ the Nucleus pulposus

Answer 24

It is still undergoing endochrondral ossification so there is cartilage still surrounding the ossification centre so its difficult to see the distinction

Question 25

What ‘fibres’ are in fibrous cartilage

Answer 25

collagen fibres - dark blue and can insert into bone

Question 26

What does blue coloured tissue indicate vs red colour in a spinal segment slide

Answer 26

The blue colour is cartilage/ nucleus pulposus whereas the red is ossification- becoming bone