Orthopaedics - wrist & hand Flashcards
Distal radius fractures pathophysiology
Most commonly caused by a fall on an outstretched hand (FOOSH)
Due to osteoporosis, the risk of these fractures increases with age
Distal radius takes 80% of the axial load underneath the scaphoid and lunate fossae -> FOOSH causes a forced supination/pronation of the carpus, this in turn increased the impaction load of the distal radius
Colles’ fracture
Extra-articular fracture of the distal radius with dorsal angulation and dorsal displacement within 2cm of the articular surface
Typically occurs as a fragility fracture in osteoporotic bone
Occurs when a person falls forwards & plants their outstretched hand in front of them -> transfer of load as their body falls forces the wrist into supination
Smith’s fracture
Volar angulation of the distal fragment of an extra-articular fracture of the distal radius, with/without volar displacement
This type of fracture is caused by falling backwards & planting the outstretched hand behind the body, causing a force pronation type injury
Barton’s fracture
Intra-articular fracture of the distal radius with associated dislocation of the radio-carpal joint
Can be described as volar or dorsal
Distal radius fractures risk factors
Increasing age
Female gender
Early menopause
Smoking/alcohol excess
Prolonged steroid use
Distal radius fractures clinical features
Present following an episode of trauma, complaining of immediate pain +/- deformity & sudden swelling around the fracture site
Any neurological involvement can also result in paraesthesia/weakness
Examination – important to assess for any evidence of neurovascular compromise
- Nerve function
- Limb perfusion: CRT & pulses
Examine the joints above and below to identify occult injuries
Distal radius fracture neurological examination
Median nerve
- Motor: abduction of the thumb
- Sensory: radial surface of distal 2nd digit
- AIN: opposition of the thumb & index finger
Ulnar nerve
- Motor: adduction of the thumb
- Sensory: ulnar surface of the distal 5th digit
Radial nerve
- Motor: extension of IPJ of thumb
- Sensory: dorsal surface of 1st webspace
Distal radius fracture investigations
Plain radiographs – AP and lateral:
1) Radial height <11mm
2) Radial inclination < 22 degrees
3) Radial (volar) tilt > 11 degrees
CT/MRI – operative planning
Distal radius fracture conservative management
Suitable resuscitation and stabilisation of the patient
Closed reduction in ED, can be performed with a haematoma block or Bier’s block
Below-elbow backslab cast, then radiographs repeated after 1 week to check for displacement
Once sufficient bone healing has occurred, patients should be rehabilitated via physiotherapy
Distal radius fracture surgical management
Significantly displaced/unstable fractures
Open reduction and internal fixation with plating/K-wire fixation
Patients will be placed in a cast to ensure ongoing immobility for a few weeks
Distal radius fracture complications
Malunion – poor realignment leads to shorted radius compared to the ulnar
- Treated with corrective osteotomy of the malunion
Median nerve compression
Osteoarthritis
Scaphoid fractures pathophysiology
Scaphoid is anatomically divided into three parts – proximal pole, waist and distal pole
Dorsal branch of the radial artery enters in the distal pole & travels in a retrograde fashion towards the proximal pole
Therefore, fractures can compromise the blood supply & lead to avascular necrosis (more proximal the fracture, the higher the risk of AVN)
Scaphoid fracture clinical features
Fractured following trauma which is often high energy
Complain of sudden onset wrist pain & bruising may be present
Tenderness in the floor of the anatomical snuffbox, pain on palpating the scaphoid tubercle & pain on telescoping of the thumb
Scaphoid fracture investigations
Initial plain radiographs should be taken – scaphoid series should be requested: AP, lateral & oblique views
Not always detected by initial radiographs, if there is sufficient clinical suspicion, patient should have wrist immobilised in a thumb splint & repeat plain radiographs in 10-14 days
If repeat radiographic imaging is negative, but clinical findings are still positive, MRI scan is indicated
Scaphoid fracture management
Undisplaced fractures – strict immobilisation in a plaster with a thumb spica splint
- Undisplaced fractures of the proximal pole have a high risk of AVN -> surgical treatment may be advocated
All displaced fractures – fixed operatively
- Most common operative technique is using a percutaneous variable-pitched screw
Scaphoid fractures complications
Avascular necrosis
Non-union – the bone is failing to heal properly, most commonly due to poor blood supply
- Managed with internal fixation and bone grafts
Carpal tunnel syndrome
Compression of the median nerve within the carpal tunnel of the wrist due to a raised pressure within this compartment
Carpal tunnel syndrome risk factors
Female gender
Increasing age
Pregnancy
Obesity
Previous injury to the wrist
Associated with other conditions – diabetes mellitus, rheumatoid arthritis & hypothyroidism
Repetitive hand or wrist movements