Orthopaedics - General Principles Flashcards
What is compartment syndrome?
A critical increase in pressure within a confined compartment
Within what time period, should compartment syndrome be treated?
Within 6 hours - surgical emergency
Describe the pathophysiology of compartment syndrome
- Critical increase in pressure within compartment due to swelling
- Venous collapse
- Venous congestion
- Further increase in pressure
- Arterial blood flow compromised
- Reduction in perfusion pressure to tissue
- Ischaemia
- Necrosis
What are the complications of compartment syndrome? (5)
- Ischaemia
- Necrosis
- Permanent disability of region
- Limb loss
- Death
What is an example of a permanent disability that can result from compartment syndrome? Describe it.
Volkmann ischaemic contracture
Permanent flexion contracture of the forearm muscles resulting in claw-like deformity of hands, wrist and fingers
What causes Volkmann ischaemic contracture as a result of compartment syndrome?
Ischaemia results in infarcted muscle that can’t regenerate and is replaced by inelastic fibrous tissue
State 4 causes of compartment syndrome
Traumatic injury -e.g. fractures
Post-surgery - e.g. iatrogenic vascular injury
DVT
Tight casts/splints
What is the most common site for compartment syndrome?
Name some other sites
Anterior tibial compartment
Lower limb - fibular, posterior deep, posterior superficial
Forearm - ventral, dorsal
What is a common sign associated with anterior tibial compartment syndrome?
Anaesthesia in the first web space due to compression of the deep fibular nerve
What are the clinical signs associated with compartment syndrome? (6) Which ones are early signs?
Pain (early) Pallor Paraesthesia (early) Perishingly cold Paralysis Pulseless
How is compartment syndrome diagnosed?
Usually by clinical signs
If in doubt, pressure in compartment can be measured using catheter or MRI
What is the supportive management for compartment syndrome? (5)
Keep limb at neutral level Opioid analgesia High flow oxygen Fluids Remove constricting dressings
What is the definitive surgical management of compartment syndrome?
Emergency open fasciotomy
How is an emergency open fasciotomy performed?
Cut fascia in compartment to relieve pressure
Wait 2 days - if healed; suture wound, if necrotic; debridement
Why do U+Es and renal function need to be monitored closely in compartment syndrome?
Risk of rhabdomyolysis
What is rhabdomyolysis?
Rapid destruction of skeletal muscle resulting in leakage of myoglobin and other enzymes which affects kidney function
What is septic arthritis?
Infection of a joint
What is the typical presentation seen in septic arthritis?
Acute onset, single, painful, swollen joint (this presentation is septic arthritis until proven otherwise)
What are the typical causative organisms in septic arthritis? (3)
Staph aureus (most common in adults) Streptococci Neisseria gonorrhoea (young, sexually active)
What are routes of infection in septic arthritis? (3)
Bacteraemia
Direct inoculation
Spread from adjacent osteomyelitis
Name two complications of septic arthritis?
Osteoarthritis
Osteomyelitis
What is osteomyelitis?
Infection of bone
What are some alternative differential diagnoses to septic arthritis (swollen, painful joint)? (3)
Gout
Pseudogout
Rheumatoid arthritis
Psoriatic arthritis
What are some risk factors for septic arthritis? (5)
Age > 80 yrs Diabetes Immunosuppression Pre-existing joint disease - e.g. RA/OA Prosthetic joints
What signs on examination are seen in septic arthritis? (4)
Redness
Warmth
Joint effusion
Pain on passive/active movement (unable to weight-bear)
What investigations can be performed in suspected septic arthritis? (3)
Routine bloods
Joint aspiration with fluid analysis
Plain radiograph
What bloods should be done in suspected septic arthritis?
FBC ESR, CRP Urate Autoantibodies e.g. RF, ANA, anti-CCP Cultures
What does analysis of joint fluid in suspected septic arthritis involve? (4)
Gram stain
Culture
Leukocyte count
Polarising microscopy
What is seen on x-ray in septic arthritis?
Normal in early stages
May show capsule/soft tissue swelling, joint space widening
What is the management for septic arthritis? (3)
A-E assessment - including sepsis 6 if necessary
Empirical IV antibiotics
Surgical wash out - irrigation and drainage
What is antibiotic prescription in septic arthritis based on? How long are they typically prescribed for?
Joint fluid culture
4-6 weeks
What are the most common metastases to bone? (6)
Breast Prostate Thyroid Renal Lung Myeloma
Give two examples of benign tumours of bone
Osteoma
Osteoblastoma
Give two examples of benign tumours of cartilage
Chondroma
Chondroblastoma
Give an example of a benign fibrous tumour
Fibroma
Name a malignant…
Bone tumour
Cartilage tumour
Fibrous tumour
Osteosarcoma
Chondrosarcoma
Fibrosarcoma
State four x-ray features of benign bone tumours
Well-defined, sclerotic border
Lack of soft tissue mass
Solid, periosteal reaction
Geographic bone destruction
State four x-ray features of malignant bone tumours
Wide zone of transition
Soft tissue mass
Interrupted periosteal reaction
Moth-eaten bone destruction
What are the 5 stages of bone fracture repair?
Haematoma formation Inflammatory reaction Bony callus formation Consolidation Bony remodelling
What happens in the haematoma formation stage of fracture repair?
A blood clot forms at the fracture site due to tissue damage and bleeding
Necrosis of few mm of bone ends
What happens in the inflammatory reaction stage of fracture repair?
Granulation tissue forms as inflammatory cells appear in the haematoma at the fracture site
What happens in the bony callus formation stage of fracture repair?
Granulation tissue —> fibrocartilaginous callus (bony trabeculae develop)
Increase in osteoblasts/osteoclasts - dead bone is absorbed by osteoclasts
Woven (spongy) bone callus formed through endochondral/intramembranous ossification
What happens in the consolidation stage of fracture repair?
How long does it last?
Woven (spongy) bone replaced by cortical (lamellar) bone until the fracture has united
Around 2 months
What happens in the bony remodelling stage of fracture repair?
How long does it last?
Newly formed bone is remodelled to resemble the normal structure
Several months
Name 5 types/classifications of fractures
Traverse
Linear
Oblique (displaced/non-displaced)
Spiral
What four factors should be considered in a displaced fracture?
STAR
Shortened
Translated
Angulated (varus/valgus)
Rotated
An open fracture is a __________ emergency
Surgical
What is an open fracture vs closed fracture?
Open = direct communication to the external environment via a wound/break in the skin near a fracture site
Closed = no direct communication to the external via a wound/break in the skin near a fracture site
What two mechanisms can an open fracture occur by?
In-to-out injury - e.g. sharp bone edges penetrate skin from beneath
Out-to-in injury - e.g. high energy, skin penetrating injury from a direct blow
State some common sites where an open fracture can occur
Tibial
Phalangeal
Forearm
Ankle
What are the complications of an open fracture?
Skin/soft tissue loss or damage
Neurovascular injury
Infection
What can be used to classify open fractures?
Gustilo-Anderson classification
What score can be used to estimate viability of an extremity after trauma?
What does the score determine?
MESS
Mangled Extremity Severity Score
Determines need for salvage vs amputation
What immediate management is specific to open fractures? (3)
Remove any gross debris and dress wound with saline-soaked gauze
IV broad spectrum antibiotic - e.g. co-amoxiclav
Check tetanus status and administer tetanus prophylaxis if required
What IV antibiotic would be appropriate in a contaminated open fracture?
Gentamicin
What tetanus prophylaxis should be given in immunised and non-immunised patients?
Immunised - toxoid
Non-immunised - human antiserum
What does reduction in the immediate management of a fracture involve?
Realignment and splinting of the limb
What is the definitive management in an open fracture?
Surgery
What does surgical management of an open fracture involve? (4)
Wound debridement and wound excision
Reduction and hold
Soft tissue coverage
Vascular compromise
What are the general principles of fracture management? (3)
What do they involve?
Reduction - improves position of the fragments
Hold - hold fragments until they unite
Rehabilitate
State two factors that promote fracture healing
Muscle activity (exercise)
Bone loading (weight bearing)
What investigation can be performed if there is no detection of a fracture on x-ray but patient is exhibiting clinical signs of a fracture?
MRI scan
What is the causative organism in tetanus?
Clostridium tetani
What type of organism is Clostridium tetani?
Gram positive, rod, obligate anaerobe, spore-forming
What is the route of infection in tetanus?
Enters the body through broken skin
What is the pathophysiology of Clostridium tetani infection?
Produces neurotoxins which reach the CNS through retrograde axonal transport
Toxins bind to receptors of peripheral nerves —> CNS
Prevents the release of inhibitory neurotransmitters (GABA and glycine) from interneurones and leads to uncontrolled activation of alpha motor neurones
What are the symptoms of tetanus infection?
Flu-like symptoms
Headache
Painful descending muscle stiffness and spasm
What is trismus?
Lockjaw due to tonic spasms of jaw musculature caused by tetanus infection
What is reduction in relation to fracture repair?
Why is it important?
What medication does it require? Why?
Realignment of fracture ends to original state
Greater the contact surface between fragments the more likely healing is to occur
Analgesia
Painful
Apart from improving healing, why else is reduction important? (3)
Tamponades bleeding at fracture site
Reduces traction on surround soft tissues and nerves (reducing swelling and risk of neuropraxia)
Reduces pressures on surrounding blood vessels (improving blood supply)
State 3 methods of reduction
Are they open or closed?
Manipulation (closed)
Mechanical traction (closed)
Open operation (open)
For which fractures, is manipulation used as the method of reduction?
What does it involve?
Minimally displaced fractures
Fractures in children
A threefold manoeuvre under local or general anaesthetic
For which fractures, is mechanical traction used as the method of reduction?
What does it involve?
Fractures that are difficult to reduce by manipulation due to powerful muscle pull - e.g. femoral shaft
Fracture is held into place until it starts to unite, aided by image intensification under local or general anaesthetic
When is open operation used as the method of reduction for a fracture?
When closed reduction fails
What is meant by hold in relation to fracture healing?
Prevention of displacement and some restriction of movement to alleviate pain, promote soft-tissue healing and to allow for movement of unaffected part of limb
What is important to consider before hold (in fracture repair)? (4)
Whether traction is required
Whether patient can weight bear
Whether thromboprophylaxis is required
Risk of compartment syndrome
Name 4 methods of holding in fracture repair
Simple splint and plaster cast
Functional bracing
External fixation
Internal fixation
What is a simple sprint and plaster cast as a method of fracture hold?
When is it used?
Plaster of Paris applied over the whole joint
Distal limb fractures
Most children’s fractures
What is functional bracing as a method of fracture hold?
What fractures is it used for?
Where either plaster of Paris or a lighter material is applied only over shafts of the bone with the joints free
Fractures of the femur or tibia
What is external fixation as a method of fracture hold?
For what fractures is it used?
The bone is transfixed above and below the fracture with screws or pins which are clamped to the frame
Fractures with severe soft tissue damage
Severely comminuted and unstable fractures
Fractures with neurovascular damage
Infected fractures
What is internal fixation as a method of fracture hold?
For what fractures is it used?
Bone fragments may be fixed with screws, transfixing pins or nails, a metal plate held by screws, a long intramedullary nail or combination of these methods
Fractures that cannot be reduced except by operation
Unstable fractures
Pathological fractures
Multiple fractures
What is the difference between a simple splint and plaster cast and functional bracing with regards to joint movement?
Functional bracing - joint can be moved
Simple splint and plaster cast - joint cannot be moved
Why aren’t fractures circumferential for the first 2 weeks?
Allows fracture to swell, otherwise patient becomes at risk of compartment syndrome
When should a plaster cross both the joint above and below?
If there is axial instability so the fracture can rotate along its axis - e.g. combined tibia/fibula or radius/ulna metaphyseal fractures
What are bone morphogenetic proteins (BMPs)?
A chemical mediator that stimulates chondrogenesis and bone formation
What is bone induction?
Where BMPs are extracted from bone matrix to promote fracture healing and bone-graft replacement
What is bone grafting?
Replacement of missing bone in order to repair complex bone fractures
How does smoking affect fracture healing?
Adversely affects…
Bone mineral density
Dynamics of bone and wound healing due to microvascular damage
