Injury & healing Flashcards
What is a fracture?
A broken bone, it will heal whether or not a physician rests it in its anatomical position
What will happen to the bone during a fracture if it is not rest correctly?
The healing process will rebuild new bone but keep the bone in its deformed position
What is closed reduction?
Manipulation of broken bone, and set into natural position without surgical intervention
What is open reduction?
Requires surgery to expose the fracture and reset the bone
How are fractures classified?
Complexity
location
specific features
What are the 6 types of fracture?
Transverse Oblique spiral comminuted impacted greenstick
What is a transverse fracture?
Occurs straight across the long axis of the bone
What is an oblique fracture?
Occurs at an angle that is not perpendicular
What is a spiral fracture?
Bone segments are pulled apart as a result of twisting motion
What is a comminuted fracture?
Multiple breaks result in many small pieces between two large segments
What is classified as a simple comminuted fracture?
2 pieces
What is an impacted fracture?
One fragment is driven into the other, as a result of compression
What is a greenstick fracture?
Partial fracture in which one side of the bone is broken
What is an open fracture?
A fracture in which at least one end of the bone penetrates the skin, presenting potential risk of infection
What is a closed fracture?
A fracture in which the skin remains intact
What are displaced bone fractures?
Occurs when bony ends are not aligned
What is a stress fracture?
Repetitive application of forces on particular bone results in stress exertion on localised region -> Exceeds remodelling capacity causing bone weakening, stress fracture occurs
When does a bone experience stress?
Whenever a force is loaded upon it (Pull of a muscle or shock of a weight bearing extremity contacting the ground)
What does ADL mean?
Activities of daily living
What happens to bone when a force is removed?
The bone elastically rebounds to its original position. The force that a bone can endure and rebound back without damage is referred to as being within the elastic range
What are the weight baring bones?
Tibia, metatarsals, navicular
What is the female triad?
1) Amenorrhoea
2) Osteoporosis
3) Disordered eating
Why does osteoporosis increase risk of fractures?
Reduced bone mineral density, increasing porous structure
What are the pathological causes of fractures?
Osteoporosis Malignancy Vitamin D deficiency Osteomyelitis Osteogenesis imperfecta Paget's disease
What does vitamin D deficiency do to bone?
Osteomalacia + ricket’s
What are the 3 mechanisms of actions for fractures?
Pathological
Stress
Trauma
What is a trauma fracture?
Low energy and high energy transfer to bone
What is a stress fracture?
Abnormal stresses on normal bone
What is a pathological fracture?
Normal stresses on abnormal bone
What type of fracture is common for patients with osteoporosis?
Low energy trauma
How does osteoporosis and osteopenia occur?
Bone remodelling imbalance, bone resorption (osteoclast activity) > bone formation (osteoblast activity)
Which ligand is a mediator of osteoclast activity?
RANKL
What is the ratio for osteoporosis incidences between females: males?
4:1
When is the average age range for senile osteoporosis?
> 70
What is secondary osteoporosis typically associated with?
Hypogonadism
Glucocorticoid excess
alcoholism
What are the three most common fragility fractures?
Wrist, hip and spine
Low energy trauma
What T score is equivalent to osteoporosis?
-2.5
What T score range is diagnostic of osteopenia?
-1 –> -2.5
Why does menopause cause osteoporosis?
Oestrogen deficiency contributes towards excessive bone resorption. Osteoblasts, osteocytes, and osteoclasts express oestrogen receptors on their cell-surface membrane.
Function: Oestrogen prevents bone loss through the inhibition of osteoclastic bone resorption.
Oestrogen indirectly causes the increased production of transforming growth factor-beta that enhances osteoclast apoptosis. In the absence of oestrogen, T cells promote osteoclast recruitment ,and prolonged survival of interleukin-1, IL-6, and TNF-⍺. IL-6 contributes to the recruitment of osteoclasts.
Osteoblasts secrete IL-6 involved in osteoclast activation.
Post-menopausal women therefore exhibit an oestrogen deficiency, consequently stimulating osteoclastic activity due to a reduction in inhibitory effect, leading to osteoporosis.
What are the main examples of lytic cancers?
Breast, kidney, thyroid and lung
Which type of cancer has the ability to metastasis bone?
Lytic cancers (breast, kidney, thyroid and lung)
What are lytic cancers associated with?
Associated with reduction in size –> Referring to thinning and bone degradation
What are plastic cancers associated with?
Hyperplasia and hypertrophic mechanisms
What are the four main primary bone cancers?
Osteosarcoma
Chondrosarcoma
Ewing sarcoma
chroma
What pathology is associated with pre-epiphyseal closure vitamin D deficiency?
Rickets
What pathology is associated with post-epiphyseal closure vitamin D deficiency?
Osteomalacia
What are the consequences of a calcitriol deficiency?
reduced calcitriol activity Hypocalcaemic conditions (Reduced Ca2+ absorption, renal reabsorption, & hyperparathyroidism)
What is the inheritance pattern of osteogenesis imperfecta?
hereditary - autosomal dominant/recessive
Which type of collagen is reduced in osteogenesis imperfecta?
Type 1 collagen
What is the function of collagen?
Collagen is an extracellular matrix protein secreted by fibroblasts & osteoblasts, and organised into insoluble fibres, comprising the extracellular matrix surrounding cells Provides mechanical strength & rigidity to tissues and organs, especially to skeletal tissues: Bone, cartilage, tendons & ligaments.
What is the main feature of osteogenesis?
Reduced fracture of long bones
What is the aetiology of Paget’s disease?
Genetic and acquired factors
What is Paget’s disease?
Excessive bone degradation and disorganised bone remodelling -> Deformity, pain fracture, or arthritis. May transform into malignant disease
What are the four stages of Paget’s disease?
1) Osteoclastic activity (increased bone resorption)
2) Mixed osteoclastic - osteoblastic activity (imbalance) results in disorganised bone remodelling, considering the osteoid scaffold is disrupted., and diverted through osteoclastic activity –> deformities arises
3) Osteoblastic activity
4) Malignancy degeneration
What three main factors influence fracture healing?
Depends on type, severity, and distance between bone fragments
What is direct bone healing?
Bones may heal directly by constructing new bone onto the fracture site -> Bone remodelling associated with osteoclast & osteoblast activity
What is the first step of fracture healing?
Bleeding/haematoma
What is a haematoma, and the first stage of fracture healing associated with?
Prostaglandin/cytokine released; growth factors increase local blood flow –> Periosteal supply dominates
Which blood supply dominates within step 1 fracture healing?
Periosteal supply
When does step 1 fracture healing occur?
Week 1
When does step 2 fracture healing occur?
Week 2-4
What happens during step 2 fracture healing?
Granulation (connective/fibrotic) tissue deposited –> Soft callus (Type II collagen) -> cartilage; fibroblasts, woven bone (immature bone)
What forms during step 2 fracture healing?
Soft callus
Which type of collagen forms the soft callus?
Type 2 collagen
What happens during step 3 fracture healing?
Fracture is bridged with soft callus –> Hard callus formation succeeds (laying down of osteoid –> type 1 collagen) facilitated by increased osteoblast activity
When does step 3 fracture healing occur?
1-4 months
When does stage 4 fracture healing occur?
4-12 months
How is bone remodelled during stage 4 fracture healing?
Endochondral ossification
What happens during stage 4 fracture healing?
Bone is remodelled through endochondral ossification lamellar bone in its place. Callus responds to activity, external forces, and the functional demands exerted onto bone; therefore this stimulates a balance of osteoblast & osteoclast activity to remodel bone (removal of excess).
What re the four stages of fracture healing?
Haemtoma
Soft callus
hard callus
remodelling (endochondral ossification, osteoblast activity lamellar bone is integrated).
What does Wolff’s Law state?
Wolff’s Law: States that bone grows and remodels in response to the forces that are exerted onto it. Placing specific stress in specific directions stimulates osteocyte activity.
Osteocyte apoptosis during disuse.
What is primary bone healing associated with?
Intermembranous healing
Which type of bone healing, primary or secondary is associated with absolute stability?
Primary bone healing
What are the three main phases of primary bone healing?
Inflammatory phase
Reparative phase
remodelling phase
Which cells are mainly involved in primary bone healing?
Osteoblasts
Why is primary bone healing faster?
Osteoblasts move into fracture. In primary bone healing, the bone ends are in contact , osteoblasts can traverse across, and bone formation is accelerated, membrane forms. Membrane formation behaves as a conduit for osteoblasts to pass
What is the inflammatory phase of bone healing?
Broken bones result in disrupted blood vessels, thus formation of a blood clot & haematoma. Inflammatory reaction results in cytokine release, growth factors & prostaglandins.
Fracture haematoma becomes organised and infiltrated by fibrovascular tissues, forming matrix for bone formation & primary callus
What factors are released during the inflammatory phase of bone healing?
Cytokine ,prostaglandins, and growth factors
What structure forms during the inflammatory phase of primary bone healing?
Primary callus
What is the approximate duration of the inflammatory phase?
Duration: Hours - days
Where does the thick mass callus form during the reparative phase of bone healing?
Around bone ends
Which cells are recruited during the reparative phase of bone healing?
Osteoblasts are recruited to deposit type 1 collagen, derived from osteoid
When is bone healing evident on radiographs?
7-10 days
What happens during the reparative phase to the soft callus?
Soft callus transforms into hard callus
What is a soft callus?
Plastic, easily performed or bend, if the fracture is not adequately supported
What is a hard callus?
Weaker in comparison to normal bone
Better capability to withstand external forces to the stage of clinical union
What is the stage of clinical union in terms of bone healing?
Fracture is not tender to palpation or with movement
Which phase of bone healing is the longest?
Remodelling phase
What is the average duration of the remodelling phase of bone healing?
Months-years
During remodelling which law is obeyed?
Wolf’s Law
How is the external callus removed during the remodelling phase of bone healing?
The external callus is no longer required, therefore is removed through osteoclast activity, and fracture site is smoothed & sculpted
In which phase of bone healing is the epiphyses realigned and residual angulation corrected?
Remodelling
What type of healing is associated with secondary bone healing?
Endochondral healing
Which responses are involved in endochondral healing?
Involves responses in the periosteum and external soft tissue –> Relative stability
Why is secondary bone healing less effective than primary bone healing?
Osteoblasts cannot jump across the gap. Cells derived from the periosteum causes osteoblasts to form osteoid, this bone formation joins the bone - cartilage precursor. Bone formation is unregulated, thus callus formation occurs
What is the average healing time?
3-12 weeks depending on site
What is the average length of time for phalange healing?
3 weeks
What is the average length of time for metacarpal, healing?
4-6 weeks
What is the average length of time for distal radius healing?
4-6 weeks
What is the average length of time for forearm healing?
8-10 weeks
What is the average length of time for femur healing?
12 weeks
What is the average length of time for tibia healing?
10 weeks
What is reduction in terms of fracture management?
Reduction involves restoring the anatomical alignment of a fracture or dislocation of the deformed limbs
Main principle: Correct the deforming forces that results in the injury
What is the first stage of fracture management?
Reduction
How is fracture reduction performed?
Performed closed,
Why is reduced swelling an important concern during fracture management?
Reduction traction on the surrounded tissue causes reduced swelling, swollen soft tissue have high rates of wound complications
What is the main aim of reducing traction on the traversing nerves?
Reduces neuropraxia
What is the main aim of reducing pressure on blood vessels?
Restoration of affected vasculature
What are the four main stages of fracture management?
Reduction
Hold
Fixation
Rehabilitation
What is associated with hold during fracture management?
Describes fracture immobilisation, important to consider whether traction is required, whereby the muscle pull across the fracture site is strong, and the fracture is inherently unstable
What clinical devices are usually implemented to immobilise fractures?
Plaster castes
Simple splints
Why should an overlying dress be applied to the fracture site?
Enables fracture to swell
What is the main risk if an overlying dress is not applied to the fracture site?
Patient may develop compartment syndrome
What is axillary instability?
Fracture is able to rotate along its long axis
The plaster should cross both joint above and below
What is the stabilisation stage of fracture management?
Fixation
What are the two categories to fixate a fracture?
Internal (intramedullary nails, and screws)
External fixation
What does the rehabilitation phase involve during fracture management?
Refers to the requirement for majority of patients to undergo an intensive period of physiotherapy following fracture management.
Advised that patients move from non immobilised unaffected joints from the outset
What is tendinitis?
Inflammation of tendon associated from overuse (In addition to infection or rheumatic disease). Swelling, and pain results in reduced mobility of tendon & muscle.
What is tedinosis?
Chronic conditions involving deterioration of collagen within tendons. Tendinosis is caused by overuse of a tendon –> Abnormal thickening
What are the three main pathologies involved with tedinopathy?
Tendinitis
Tendinosis
Ruptured tendon
What are the three grade classifications of ligament injury?
Grade 1, II, III
What is a grade I ligament injury?
Slight incomplete tear
No notable joint instability
What is a grade II ligament injury?
Moderate/severe incomplete tear –> Some joint instability. One ligament may be completely torn
What is a grade III ligament injury?
Complete tear of 1 or more ligaments, there is an obvious indication of instability
Surgical intervention required
What is the main pathology for the inflammatory phase of bone healing?
Fibrin clots formed in ligament tears
What is the main pathology during the proliferation phase of bone healing?
Tendons & ligaments weakest, ensile strength builds
Which bone healing phase is the most painful?
Inflammatory phase
What is the main advantage of immobilisation?
Less ligament laxity (lengthening)
In terms of strength which is better, mobilisation or immobilisation of ligamentous tissue?
Mobilisation results in grater overall strength
What are the 5 main disadvantages for immobilisation of ligamentous tissue?
Less overall strength Protein degradation Production of inferior tissue Bly blast cells Bone resorption Build tissue tensile strength
What are the 2 main benefits of mobilising ligamentous tissue?
Ligament scars are wider, stronger & more elastic
Better alignment/quality of collagen
