MSK growth injury and repair

Question 1

what is a ligament

Answer 1

dense band of collagenous tissue

span joint and anchored to bone at either end

Question 2

ligament structure

Answer 2

type 1 collagen fibres
fibroblasts within them

sensory fibres: proprioception, stretch, sensation, pain

vessels on surface

crimping to allow stretch

Question 3

ligament vs tendon

Answer 3

ligaments less collagen and more proteoglycans and water - more compliant

collagen fibres less organised in ligaments and fibroblasts rounder

Question 4

what causes ligament rupture

Answer 4

forces exceed strength of ligament

expected: forces far too great for it to resist
unexpected: e.g. going over ankle

Question 5

healing of ruptured ligament

Answer 5

heamatoma - hypertrophic vascular reponse

proliferative phase - production scar tissue

remodelling - matrix becomes more ligament like

Question 6

conservative management of ligament rupture

Answer 6

for partial tears, no instability and poor surgical candidates

soft tissue brace
walker boot
cast

Question 7

operative management of ligament rupture

Answer 7

for unstable joints, need good joint performance (sportsmen), compulsory (multiple ligaments damaged)

direct repair
augmentation - add strenfth
replacement - when cannot be repaired (often piece tendon stripped from hamstrings)

Question 8

structure tendon

Answer 8

longitudinal arrangement of cells (mostly tenocytes) and fibres (collagen type 1)

Question 9

what injuries can occur to tendons

Answer 9

degeneration 
inflammation 
avulsion +/- bone fragment 
tear - intrasubstance, musculotendinous junction 
laceration/incision

Question 10

degeneration of tendon

Answer 10

intrasubstance mucoid degeneration

may be swollen, painful tendon

may be precursor to rupture

Question 11

infammation of tendon

Answer 11

e.g. de Q;s tenovaginisis

Question 12

enthesiopathy of tendon

Answer 12

inflammation at insertion to bone

e.g. tennis elbow

usually muscle origin as opposed to tendon insertion

Question 13

avulsion of tendon +/- bone fradment

Answer 13

pulling off of tendon
failure at insertion

load excessing failure strength whilst muscle contracting

e.g. mallet finger

Question 14

treatment of tendon avulsion

Answer 14

conservative: retraction tendon
operative: reattach tendon, fixation bone fragment

Question 15

intrasubstance rupture of tendon

Answer 15

somewhere middle tendon

common w achilles tendon

load exceeds failure strength

Question 16

signs achilles tendon rupture

Answer 16

+ive Simmond’s squeeze test

palpable tender gap

Question 17

conservative treatment of tendon ruptures

Answer 17

mobilise (partial rupture)

splint/cast

Question 18

when are tendon ruptures treated operatively

Answer 18

high risk re-rupture
high activity
ends cannot be opposed

Question 19

bone growth

Answer 19

start hyaline cartilage which develops primary ossification centre - allowing growth

then develop secondary ossification centre at each end. medullary cavity formed as bone grows and an epiphyseal plate forms at end of bone

Question 20

cortical bone

Answer 20

compact
multiple concentric lamellae which contain blood vessels in centre

predominantly diaphysis bone
resists bending and torsion

less biologically active, slow growing

Question 21

cancellous bone

Answer 21

spongey
can take load
usually between layers of cortical bone

lies at metaphysis (ends)

shock absorprion - resists/absorbs compression

site longitudinal growth and very biologically active

Question 22

why do bones fail/fracture

Answer 22

high energy transfer required to break normal bone

repetitive stress in normal bones - areas of micro-injury that eventually exceeds ability to repair making bone weaker

low energy transfer in abnormal bones (old people) - osteoporosis, osteomalacia

Question 23

four stages of fracture reapair

Answer 23

inflammation
soft callus
hard callus
bone remodelling

Question 24

inflammatory stage of fracture healing

Answer 24

heamatoma and fibrin clot

platelets, neutrophils, monocytes, macrophages

repair cells move in quickly: fibroblasts, mesenchymal + osteoprogenitor cells, angiognesis

Question 25

how can inflammatory stage fracture healing be affected

Answer 25

NSAIDs

loss heamatoma: open fracture, surgery

extensive tissue damage: poor tissue damage

giving platelet concentrates (to replace blood clot)

Question 26

soft callus phase of fracture healing

Answer 26

begins when pain and swelling subside

lasts until bony fragments are united by cartilage or fibrous tissue

soft and bendy

continued increase in vascularity

Question 27

how can soft callus phase of fracture healing be affected

Answer 27

replace cartilage - demineralised bone matrix

jump straight to bone - bone graft

Question 28

hard callus phase of fracture healing

Answer 28

conversion of cartilage to woven bone

woven bone can resist load

increasing bone rigidity

Question 29

bone remodelling phase of fracture healing

Answer 29

conversion of woven bone to lamellar bone

medullary canal is reconstituted

Question 30

what is delayed union

Answer 30

fracture fails to heal in time it is expected to

it can either have stopped healing or can be taking longer than normal to

Question 31

causes of delayed union

Answer 31

high energy injury 
distraction - fracture ends not close together
instability 
infection 
steroids
immune suppression 
smoking 
warfarin 
NSAIDs
ciprofloxacin

Question 32

what alternative management options are there if delayed union

Answer 32

different fixation- nail, plate, adding bone graft

dynamisation - take screwsout to bring fracture ends closer together

bone grafting

Question 33

non-union

Answer 33

failure to heal

Question 34

what can cause non-union

Answer 34

failure of calcification of fibrocartilage to form bone

instability: excessive osteoclasis

abdundant callus formation: never bridges and so end up with 2 separate masses of bone close together