Orthopaedics Mushkies Flashcards
What is the composition of bone?
Cells and Matrix
What cells are bone composed of?
Osteoblasts
Osteoclasts
Osteocytes
OPCs
What kind of matrices are bone composed of?
- Organic (40%) = Osteoid
2. Inorganic (60%)
What is organic bone matrix mainly composed of?
Collagen Type I
What is the main function of organic bone matrix?
Resists tension, twisting and bending
What is inorganic bone matrix mainly composed of?
Calcium hydroxyapatite
What is the main function of inorganic bone matrix?
Resists compressive forces
How can you classify the types of bone?
Woven bone and Lamellar Bone
What is woven bone?
Disorganised bone that forms the embryonic skeleton and fracture callus
What is lamellar bone?
Mature bone that can be of two types
What are the 2 types of lamellar bone?
- Cortical/compact = dense outer layer
2. Cancellous/trabecular = porous central layer
What are the two ways in which bone is formed?
- Intramembranous ossification
2. Endochondral ossification
What is intramembranous ossification?
Direst ossification of mesenchymal bone models formed during embryonic development e.g. skull bones, mandible and clavicle
What is endochondral ossification?
- Mesenchyme –> cartilage –> bone
2. Most bones ossify this way
What are the 3 phases of fractuer healing?
- Reactive phase
- Reparative phase
- Remodelling phase
What is the reactive phase of fracture haling?
- Injury - 48hrs
- Bleeding into # site –> haematoma
- Inflammation –> cytokine, GF and vasoactive mediator release –> recruitment of leukocytes and fibroblasts –> granulation tissue
What is the reparative phase of fracture healing?
- 2 days - 2 weeks
- Proliferation of osteoblasts and fibroblasts –> cartilage and woven bone production –> callus formation
- Consolidation (endochondral ossification) of woven bone into lamellar bone
What is the remodelling phase of fracture healing?
- 1 week - 7 years
2. Remodelling of lamellar bone to cope with mechanical forces applied to it (Wolff’s law = form follows function)
What is Wolff’s law?
Form follows function, i.e. bone in a healthy person will adapt to the loads under which it is placed
What kind of fractures have a healing time of 3 weeks?
- Closed
- Paediatrics
- Metaphyseal
- Upper limb
What complicating factors double healing time?
ALDO
- Adult
- Lower limb
- Diaphyseal
- Open
How can you classify fractures?
- Traumatic
- Stress
- Pathological
How can you classify traumatic fractures?
- Direct = assault with metal bar
- Indirect = FOOSH –> clavicle #
- Avulsion
What causes a stress fracture?
Bone fatigue due to repetitive strain e.g. foot #in marathon runners
What is a pathological fracture?
Normal forces but diseased bone
How can you classify pathological fractures?
- Local = tumours
2. General = osteoporosis, Cushing’s, Paget’s
What are some things you must take into account when requesting radiographs for fractures?
- Radiographs must be orthogonal –> request AP and lateral films
- Need images of joint above and joint below #
How do you describe a fracture?
D PAIDSS
- Demographics = pt details, date, orientation and content of image
- Pattern
- Anatomical location
- Intra/extra-articular (dislocation/subluxation)
- Deformity
- Soft tissues
- ? Specific classification/type
What are the 7 patterns of fracture?
TOMS CAG
- Transverse
- Oblique
- Multifragmentary
- Spiral
- Crush
- Avulsion
- Greenstick
What is meant by deformity and what are the 4 types of deformity?
Distal relative to proximal: TARI
- Translation
- Angulation (tilt)
- Rotation
- Impaction (shortening)
How can you describe soft tissues in a fracture?
- Open or closed
- Neurovascular status
- Compartment syndrome
What is a Colles fracture?
Distal forearm fracture in which the radius is bent backwards, typically due to falling on an outstretched hand
What is a Smith’s fracture?
Distal forearm fracture in which the distal fracture fragment is displaced volarly, typically due to falling onto a flexed hand
What is a Galeazzi fracture?
Fracture of the mid to distal third of the radius with dislocation or subluxation of the distal Radioulnar Joint (DRUJ)
What is a Monteggia fracture?
Fracture of the proximal third of the ulna with dislocation of the proximal head of the radius
What is a Salter-Harris fracture?
A fracture that involves the epiphyseal plate or growth plate of a bone, specifically the zone of provisional calcification
In general, how stable/unstable are the Garden fractures?
In general, stage I and II are stable fractures and can be treated with internal fixation (head-preservation) and stage III and VI are unstable fractures and hence treated with arthroplasty (either hemi- or total arthroplasty)
What are the types of Salter-Harris fracture?
SALTeR 1. Slip (straight across) 2. Above/Away 3. Lower 4. Through everything 5. Rammed (crushed) Types 6 to 9 are rarer and have been added later
What are the main principles of fracture management?
4 Rs
- Resuscitation
- Reduction
- Restriction
- Rehabilitation
What are the 4 components of Resuscitation in Fracture management?
FOGC
- First principles
- Open #s require urgent attention: 6 As
- Gustillo classification of open #s
- Clostridium perfringens
What are the 6 first principles of resuscitation?
- Follow ATLS guidelines
- Trauma series in primary survey = C spine, chest, pelvis
- Fractures in secondary survey
- Assess neurovascular status and look for dislocations
- Consider reduction and splinting before imaging ut reduce pain, bleeding and risk of neurovascular injury
- X-ray once stable
What is the management of an open fracture?
6 As, with ultimate management being debridement and fixation in theatre
- Analgesia
- Assess: NV status, soft tissues, photograph
- Antisepsis: wound swab, copious irrigation, cover with betadine-soaked dressing
- Alignment: align # and splint
- Anti-tetanus (check status, booster lasts 10yrs)
- Abx = Fluclox 500mg IV/IM + benpen 600mg IV/IM
What is the Gustillo classification of open fractures?
- Wound <1cm in length
- Wound >1cm in length with minimal soft tissue damage
- Extensive soft tissue damage
What is are the complications and management of C. perfringens?
- Most dangerous complication of open fracture, leading to wound infections and gas gangrene +/- shock and renal failure
- Management = debridge, benpen + clindamycin
What are the principles of fracture reduction?
- Displaced #s should be reduced unless no effect on outcome e.g. ribs
- Aim for anatomical reduction (esp if articular surfaces involved)
- Alignment is more important than opposition
What are the methods of reduction?
- Manipulation/closed reduction
- Traction
- Open reduction (and internal fixation)
What are the features of a closed reduction?
- Under local, regional or general anaesthetics
- Traction to disimpact
- Manipulation to align
What are the features of traction reduction?
- Not typically used now
- Employed to overcome contraction of large muscles e.g. femoral #
- Skeletal traction vs. skin traction
What are the features of open reduction (and internal fixation)?
- Accurate reduction vs. risks of surgery
2. Used for #: intra-articular, open, 2 in 1 limb, bilateral identical, failed conservative Rx
What are the principles of restriction>
- Interfragmentary strain hypothesis dictates that tissues formed at the site of the # depends on the strain it experiences
- Fixation –> reduced strain –> bone formation
- Fixation –> reduced pain, increased stability + ability to function
What are the 6 methods of restriction?
- Non rigid
- Plaster
- Functional bracing
- Continuous traction
- Ex-fix
- Internal fixation
What are examples of non-rigid restrictions?
Slings and elastic supports
What are plaster restrictions?
POP, in first 24-48hrs use back-slab or split cast due to risk of compartment syndrome
What is functional bracing?
Joints free to move but bone shafts supported in cast segments
What is an example of continuous traction?
Collar and cuff
What is ex-fix?
- Fragments are held in position by pins/wires which are then connected to an external frame
- Intervention is away from field of injury
- Useful in open #s, burns, tissue loss to allow wound access and reduce infection risk
- Risk of pin-site infections
What is internal fixation?
- Use of pins, plates, screws, IM nails
- Usually perfect anatomical alignment
- Increased stability
- Aid early mobilisation
What are the principles of rehabilitation?
- Immobility –> reduced muscle and bone mass, joint stiffness
- Therefore need to maximise mobility of uninjured limbs
- Quick return to function reduces later morbidity
What are methods of rehabilitation?
- Physiotherapy = exercises to improve mobility
- OT = splints, mobility aids, home modification
- Social services = meals on wheels, home help
How can you classify the complications of fractures?
General and Specific
How can you classify the general complications of fractures?
- Tissue damage
- Anaesthesia
- Prolonged bed rest
What tissue damage can occur?
- Haemorrhage and shock
- Infection
- Muscle damage –> rhabdomyolysis
What are 3 complications of anaesthesia?
- Anaphylaxis
- Aspiration
- Damage to teeth
What are complications of prolonged bed rest?
- Infection = chest, UTI
- Pressure sores and muscle wasting
- DVT, PE
- Reduced bone mineral density
How can you classify the specific complications of fractures?
- Immediate
- Early
- Late
What are the immediate specific complications of fractures?
- Neurovascular damage
2. Visceral damage
What are the early specific complications of fractures?
- Compartment syndrome
- Infection
- Fat embolism –> ARDS
What are the late specific complications of fractures?
- Problems with union
- Avascular necrosis
- Growth disturbance
- Post-traumatic osteoarthritis
- Complex regional pain syndromes
- Myositis ossificans
What is myositis ossificans?
- A condition where bone tissue forms inside muscle or other soft tissue after an injury, usually in the large muscles of the arm or legs (elbow and quadriceps)
- Due to heterotopic ossification of muscle at sites of haematoma formation, resulting in restricted, painful movement
- Can be excised surgically
What classification is used for describing the degree of nerve injury?
Seddon Classification
What are the grades of nerve injury according to the Seddon classification system?
NAN
- Neuropraxia
- Axonotmesis
- Neurotmesis
What is Neuropraxia?
Temporary interruption of conduction without loss of axonal continuity
What is Axonotmesis?
- Disruption of nerve axon –> distal Wallerian degeneration
- Connective tissue framework of nerve preserved
- Regeneration occurs and recovery is possible
What is Neurotmesis?
Disruption of entire nerve fibre –> surgery required and recovery usually not complete
What is Wallerian degeneration?
Active process of degeneration that results when a nerve fiber is cut or crushed and the part of the axon distal to the injury (i.e. farther from the neuron’s cell body) degenerates
An anterior shoulder dislocation/humeral surgical neck leads to what kind of palsy and test/result?
- Axillary nerve palsy
2. Numb chevron and weak abduction
A humeral shaft fracture leads to what kind of palsy and test/result?
- Radial nerve palsy
2. Waiter’s tip
An elbow dislocation leads to what kind of palsy and test/result?
- Ulnar nerve palsy
2. Claw hand
A hip dislocation leads to what kind of palsy and test/result?
- Sciatic nerve palsy
2. Foot drop
A neck of fibular fracture/knee dislocation leads to what kind of palsy and test/result?
- Fibular nerve palsy
2. Foot drop