Lecture 3: Injury and healing Flashcards
What are the 3 mechanisms of bone fracture?
- trauma (low energy, high energy)
- stress (abnormal stresses on normal bone)
- pathological (normal stresses on abnormal bone)
What are the different types of fracture patterns?
SOFT TISSUE INTEGRITY - open or closed
BONY FRAGMENTS - greenstick, simple or comminuted
DISPLACEMENT - displaced or undisplaced
What is an open fracture?
bone has broken through skin
What is a closed fracture?
skin is not broken
What is a displaced fracture?
bone breaks into 2 or more pieces and moves out of alignment
What is a non-displaced/undisplaced fracture?
bone breaks but doesn’t move out of alignment
What is a greenstick fracture?
an incomplete fracture in which the bone is bent, occurs most often in children
What is a simple fracture?
a fracture of the bone only, without damage to the surrounding tissues or breaking of the skin.
What is a comminuted fracture?
bone breaks into several pieces
What is an example of high energy trauma?
car crash
What is an example of low energy trauma?
falling down
How can stress lead to stress fractures?
- stress exerted on bone is greater than bones capacity to remodel
- bone weakening
- stress fracture
- risk of complete fracture
3 examples of weight-baring bones?
- tibia
- metatarsals
- navicular
related to athletes, occupation, military, female athlete triad
What are the 3 components of the female athlete triad?
- disordered eating
- amenorrhea
- osteoporosis
What are some pathological disorders affecting bones?
- osteoporosis
- malignancy (cancer)
- vitamin D deficiency
- osteomyelitis
- osteogenesis imperfecta
- Paget’s disease
What is osteopenia?
a medical condition in which the protein and mineral content of bone tissue is reduced, but less severely than in osteoporosis.
What is osteoporosis?
a medical condition in which the bones become brittle and fragile from loss of tissue, typically as a result of hormonal changes, or deficiency of calcium or vitamin D.
What causes a disrupted microarchitecture in bone?
if osteoclast activity > osteoblast activity
Is osteoporosis more common in males or females?
females
Who can get postmenopausal osteoporosis?
women aged 50 - 70
Who can get senile osteoporosis?
people aged over 70
What is secondary osteoporosis and who can get it?
osteoporosis that is a result of hypogonadism, glucocorticoid excess, alcoholism etc. (due to secondary factors)
can happen to anyone at any age, 60% males
What is osteopenia and osteoporosis associated with?
fragility fractures - hip, spine, wrist (where low energy trauma can lead to fractures)
What primary malignant tumour metastasize to bone?
- prostate (blastic - fill bone with extra cells)
- breast (blastic or lytic)
- kidney (lytic - destroy bone material)
- thyroid (lytic)
- lung (lytic)
Name some primary bone cancers?
- osteosarcoma
- chondrosarcoma
- Ewing sarcoma
- chordoma
5 causes of vit D deficiency?
- malabsorption or insufficient diet
- inadequate sun exposure
- liver disease
- renal disease
- receptor defects
What does vit D deficiency cause in children?
Rickets (bowing of legs) - before physis closure
What does vit D deficiency cause in adults?
osteomalacia - after physis closure, weaker bones
What is osteogenesis imperfecta?
‘brittle bone disease’
hereditary - autosomal dominant or recessive
- decreased type 1 collagen due to –> decreased secretion, production of abnormal collagen
- results in insufficient osteoid production
- effects: bones, hearing, heart, sight
What is Paget’s disease?
- aetiology: genetic + acquired factors
- excessive bone break down and disorganised remodelling –> deformity, pain, fracture or arthritis
- may transform into malignant disease
- 4 stages: (1) osteoclastic activity, (2) mixed osteoclastic-osteoblastic activity, (3) osteoblastic activity, (4) malignant degeneration
What is Wolff’s law?
bone grows and remodels in response to forces that are placed on it
What are the stages of fracture healing?
WEEK 1: haematoma formation, release of cytokines and granulation tissue
WEEKS 2-4/1-4 MONTHS: soft callus formation (type II collagen - cartilage), converted to hard callus (type I collagen - bone)
4-12 MONTHS: callus responds to activity, external forces, functional demands and growth, excess bone is removed
What is primary bone healing?
intermembranous healing, absolute stability (involves a direct attempt by the cortex to re-establish itself after interruption without the formation of a fracture callus) might involve plate and screws
What is secondary bone healing?
- endochondral healing
- involves responses in the periosteum and external soft tissues
- relative stability
(involves the classical stages of injury, haemorrhage inflammation, primary soft callus formation, callus mineralization, and callus remodelling)
Outline fracture healing times?
3-12 weeks depending on site Signs of healing visible on x-ray from 7-10 days - phalanges: 3 weeks - metacarpals: 4-6 weeks - distal radius: 4-6 weeks - forearm: 8-10 weeks - femur: 12 weeks - tibia: 10 weeks
What are the 3 stages of fracture management?
- reduce
- hold
- rehabilitate
What is reduction in fracture management?
realignment of the bone to prevent deformities
OPEN: surgical incision made to expose fragments and put them back in proper position (can be mini or full exposure)
CLOSED: displaced or fractured bone fragments are manipulated back into proper position or alignment w/o surgically exposing them (manipulation or traction which can be skin e.g. cast/bandaging or skeletal e.g. pins in bones)
What is the hold phase of fracture management?
choosing how to hold the fracture - if it’s closed then use plaster or traction (skin or skeletal - pins in bones)
might need fixation
What is fixation in fracture management?
stabilizing the fractured bone
can be:
- external: metal outside skin (can be monoplanar or multiplanar)
- internal: metal underneath skin
Internal can be:
- intramedullary: into canal of bone (pins and nails)
- extramedullary: into surface of bone (plates/screws and pins)
What is the rehabilitate phase of fracture management?
- use (pain relief, retrain)
- move
- strengthen
- weight-bear
to reverse effects of muscular atrophy
What needs to be considered in fracture management?
- is the fracture displaced?
- is it stable? (soft tissues OK?, other illnesses?)
or - is it at a joint surface? (what does the patient think)
What is soft tissue injury?
INJURY TO:
muscle - force and motion
ligament - connect bone to bone
tendon - connect muscle to bone
What is tendinopathy?
pathologies of the tendon
- tendinosis (abnormal thickening)
- tendinitis (inflammation)
- rupture
Ligament injury classifications?
Grade I - slight incomplete tear - no notable joint instability
Grade II - moderate/severe incomplete tear - some joint instability, one ligament may be completely torn
Grade III - complete tearing of 1 or more ligaments, obvious instability, surgery usually required
What are the phases of ligament healing?
- inflammatory phase, 1-7 days, fibrin clot formed in ligament tears
- proliferation phase, 7-21 days, tendons and ligaments weakest, tensile strength builds
- remodelling, >14 days, tendons and ligaments heal with scar tissue that reduces ultimate strength causes adhesions
- maturation, weeks to years, max. strength reached within a year
What factors affect tissue healing?
- mechanical environment - movement, forces
- biological environment - blood supply, immune function (autoimmune conditions), infection, nutrition
What are the effects of immobilisation on injured ligamentous tissue?
GOOD - less ligament laxity (lengthening)
BAD:
- less overall strength of ligament repair scar
- protein degradation exceeds protein synthesis (collagen quantity)
- production of inferior tissue by blast cells
- resorption of bone at site of ligament insertion
- build tissue tensile strength (50% in 6-9 weeks)
What are the benefits of mobilisation (movement) on injured ligamentous tissue?
- ligament scars are wider, stronger and more elastic
- better alignment/quality of collagen
