Fracture of radius and ulna
Forearm fractures account for most limb fractures. Wrist fractures are the most common forearm fracture. Fracture risk factors include osteoporosis (more common in women than men) and malignancy (pathological fractures).
- Forearm fractures can be classified as either proximal, middle or distal.
- They can affect one or both forearm bones.
- They are either open or closed.
- Proximal forearm fractures may involve the elbow joint
- Distal forearm fractures may involve the wrist
General assessment and initial management of forearm fractures:
Some general principles should be followed for all forearm fractures. Specific points related to the different fracture types are discussed below. Forearm fractures in children can generally be treated differently from adult fractures because of continuing bone growth in the radius and the ulna after the fracture has healed.
- Assess Airway, Breathing and Circulation and manage as necessary.
- Assess upper limb neurovascular function
- Sensory function: the median nerve supplies the thumb, index, middle and radial half of the ring finger on the palmar side of the hand and the tip of the thumb, index, middle and ring finger on dorsum of the hand; the radial nerve supplies the dorsolateral aspect of the hand and the dorsal aspect of the thumb, index, middle and lateral half of the ring fingers; the ulnar nerve supplies the dorsal and palmar aspects of the medial half of the ring finger and the whole of the little finger.
- Motor function: test anterior interosseous branch of the median nerve by asking patient to make the ‘OK’ sign; test radial nerve by asking patient to extend their fingers or wrist against resistance; test ulnar nerve by asking patient to separate their fingers against resistance.
- Vascular function: examine radial (and ulnar) pulse. Assess capillary refill.
- Examine the wrist, elbow and forearm for tenderness and range of motion.
- Perform a complete examination for other injuries.
- Immobilize the forearm and upper arm whilst waiting for Xray.
- Provide analgesia.
- Immediate fracture reduction is required if there is neurovascular compromise, severe displacement or skin tenting.
Adult both-bone forearm fractures:
- Mechanism of injury: usually significant force injury. Most commonly occur in motor vehicle accidents, also occur from direct blow, fall from a height or during sport.
- Presentation: pain and swelling at site with obvious deformity.
- Assessment: may be nerve involvement with paraesthesiae, paresis or loss of function. Do not elicit crepitus as may cause further soft tissue injury. Do not probe open fractures as may cause deeper contamination.
- Investigation: X-ray entire length of forearm, wrist and elbow, with AP and lateral views.
- Management: displaced fractures are the usual situation in adults. Operative treatment with internal fixation or intramedullary nailing will be needed in nearly all cases, so refer urgently. Closed reduction may be attempted (with sufficient sedation/analgesia ± muscle relaxants) if there is acute neurovascular compromise.
Paediatric both-bone forearm fractures:
Fractures may be of greenstick type (incomplete) or complete. A greenstick fracture can occur in one bone with a complete fracture in the other. Complete fractures may be undisplaced, minimally displaced or overriding. Fractures of the proximal third are relatively rare. Middle third fractures account for about 18% of both-bones fractures and distal third about 75%.
- Mechanism of injury: usually an indirect injury following fall on outstretched hand. Occasionally caused by direct trauma.
- Presentation: pain, swelling and deformity at fracture site.
- Investigation: X-rays of wrist, elbow and whole forearm should be taken.
- Management: unlike adults, many both-bone fractures of the forearm can be treated by closed reduction. After reduction, forearm pronation and supination should be checked and arm placed in a long-arm cast or splint. Surgical treatment is by open reduction and plating/intramedullary nails depending on degree of overriding/angulation.
Radial shaft fractures (Gallezzi fractures)
- Definition: solitary fractures of the distal one third of the radius with accompanying subluxation or dislocation of distal radioulnar joint (DRUJ). Synonym is reverse Monteggia fracture.
- Mechanism of injury: commonly caused by fall on extended, pronated wrist.
- Presentation: pain, swelling and deformity of the wrist and forearm. Tenderness and swelling at the distal radius and tenderness at DRUJ.
- Investigation: X-ray the entire length of the forearm including wrist and elbow joints, AP and lateral views usually sufficient.
- Management: in adults, requires surgical open reduction of the distal radius and DRUJ with internal fixation. In children the fracture can often be treated by closed reduction with longitudinal traction and correction of radial angulation. General anaesthesia may be required in difficult cases. If closed reduction under GA fails, K-wire insertion may be needed to lever the fracture into position. Open reduction may be needed in some cases.4
Ulna shaft fractures:
- Definition: isolated mid-shaft ulna fractures have the synonym ‘nightstick fracture’.
- Mechanism of injury: usually caused by a direct blow to the ulnar border, classically if someone receives a blow from an object whilst raising their arm in defence.5
- Presentation: point tenderness over ulna shaft and forearm swelling.
- Investigation: need to x-ray ulna from wrist to elbow.
- Management: require orthopaedic referral. Non-displaced or minimally-displaced fractures can be treated with posterior splint from mid-upper arm to dorsum of the metacarpal joints with wrist in slight extension, forearm in neutral position and elbow at 90°. After 7-10 days, when swelling has subsided, use plaster sleeve or functional brace for next 4-6 weeks. Monitor weekly for first 3 weeks for any displacement. Fractures with marked displacement or angulation should be treated with open reduction and internal fixation.
- Definition: these are fractures of the proximal third (usually) of the ulna with associated dislocation of the radial head. Classified as:
- Type I – Fracture with anterior radial head dislocation. Commonest (60%).
- Type II – Fracture of the proximal ulna with posterior or posterolateral dislocation of the radial head (15%).
- Type III – Fracture of the ulna metaphysis with lateral or anterolateral dislocation of the radial head (20%).
- Type IV – Fracture of both radius and ulna at their proximal third with anterior dislocation of radial head (5%).
- Mechanism of injury: usually caused by a fall onto outstretched, extended and pronated elbow or direct blow.
- Presentation: acute, severe pain and swelling in forearm and elbow. Damage may occur to the posterior interosseous nerve.
- Investigation: X-ray the entire length of radius and ulna, including wrist and elbow, AP and lateral views usually sufficient but may need radiocapitellar views.
- Management: in adults, immobilize joint in splint and refer for open reduction and internal fixation. Most paediatric monteggia fractures are treated closed.7
Complications of forearm fractures:
- Non-union and malunion (uncommon)
- Compromise of brachial/radial artery blood supply
- Median, ulnar or radial nerve injury
- Infection (more likely if fracture secondary to crush injury)
- Compartment syndrome (more common in both-bone forearm fractures)
- Radioulnar fusion (synostosis)
Prevention of forearm fractures
- Prevention of osteoporosis.
- Adequate treatment of existing osteoporosis.
- The use of wrist and elbow guards whilst taking part in certain sports activities such as mountain biking and skating.