MSK growth injury and repair Flashcards
what is a ligament
dense band of collagenous tissue
span joint and anchored to bone at either end
ligament structure
type 1 collagen fibres
fibroblasts within them
sensory fibres: proprioception, stretch, sensation, pain
vessels on surface
crimping to allow stretch
ligament vs tendon
ligaments less collagen and more proteoglycans and water - more compliant
collagen fibres less organised in ligaments and fibroblasts rounder
what causes ligament rupture
forces exceed strength of ligament
expected: forces far too great for it to resist
unexpected: e.g. going over ankle
healing of ruptured ligament
heamatoma - hypertrophic vascular reponse
proliferative phase - production scar tissue
remodelling - matrix becomes more ligament like
conservative management of ligament rupture
for partial tears, no instability and poor surgical candidates
soft tissue brace
walker boot
cast
operative management of ligament rupture
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)
structure tendon
longitudinal arrangement of cells (mostly tenocytes) and fibres (collagen type 1)
what injuries can occur to tendons
degeneration inflammation avulsion +/- bone fragment tear - intrasubstance, musculotendinous junction laceration/incision
degeneration of tendon
intrasubstance mucoid degeneration
may be swollen, painful tendon
may be precursor to rupture
infammation of tendon
e.g. de Q;s tenovaginisis
enthesiopathy of tendon
inflammation at insertion to bone
e.g. tennis elbow
usually muscle origin as opposed to tendon insertion
avulsion of tendon +/- bone fradment
pulling off of tendon
failure at insertion
load excessing failure strength whilst muscle contracting
e.g. mallet finger
treatment of tendon avulsion
conservative: retraction tendon
operative: reattach tendon, fixation bone fragment
intrasubstance rupture of tendon
somewhere middle tendon
common w achilles tendon
load exceeds failure strength
signs achilles tendon rupture
+ive Simmond’s squeeze test
palpable tender gap
conservative treatment of tendon ruptures
mobilise (partial rupture)
splint/cast
when are tendon ruptures treated operatively
high risk re-rupture
high activity
ends cannot be opposed
bone growth
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
cortical bone
compact
multiple concentric lamellae which contain blood vessels in centre
predominantly diaphysis bone
resists bending and torsion
less biologically active, slow growing
cancellous bone
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
why do bones fail/fracture
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
four stages of fracture reapair
inflammation
soft callus
hard callus
bone remodelling
inflammatory stage of fracture healing
heamatoma and fibrin clot
platelets, neutrophils, monocytes, macrophages
repair cells move in quickly: fibroblasts, mesenchymal + osteoprogenitor cells, angiognesis
how can inflammatory stage fracture healing be affected
NSAIDs
loss heamatoma: open fracture, surgery
extensive tissue damage: poor tissue damage
giving platelet concentrates (to replace blood clot)
soft callus phase of fracture healing
begins when pain and swelling subside
lasts until bony fragments are united by cartilage or fibrous tissue
soft and bendy
continued increase in vascularity
how can soft callus phase of fracture healing be affected
replace cartilage - demineralised bone matrix
jump straight to bone - bone graft
hard callus phase of fracture healing
conversion of cartilage to woven bone
woven bone can resist load
increasing bone rigidity
bone remodelling phase of fracture healing
conversion of woven bone to lamellar bone
medullary canal is reconstituted
what is delayed union
fracture fails to heal in time it is expected to
it can either have stopped healing or can be taking longer than normal to
causes of delayed union
high energy injury distraction - fracture ends not close together instability infection steroids immune suppression smoking warfarin NSAIDs ciprofloxacin
what alternative management options are there if delayed union
different fixation- nail, plate, adding bone graft
dynamisation - take screwsout to bring fracture ends closer together
bone grafting
non-union
failure to heal
what can cause non-union
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
