Physical Address
304 North Cardinal St.
Dorchester Center, MA 02124
Fractures of the forearm and carpal bones
Essentials
- 1
Forearm fractures are among the most common fractures seen in the emergency department (ED).
- 2
When the need for or potential success of reduction is being assessed, the external appearance of the limb is a key feature.
- 3
Median nerve function must be assessed before and after reduction of all distal radial fractures.
- 4
Splinting or functional bracing may be sufficient for stable fractures. Early movement and load bearing aid functional recovery.
- 5
General indications for orthopaedic referral include fractures that are compound, unstable, associated with intra-articular or neurovascular injury and those that have failed reduction in the ED.
- 6
Displaced, isolated fractures of the ulna or radius may be associated with a dislocation of the radius or ulna, respectively (Monteggia and Galeazzi fracture dislocations). These should be carefully sought, as they pose a high risk of long-term disability.
- 7
Significant or persistent symptoms with the absence of a visible fracture on plain x-ray may be due to an undetected fracture or significant soft tissue injury. A high index of suspicion and early review are recommended. Further investigation with bone scintigraphy, computed tomography (CT) or magnetic resonance imaging (MRI) may be indicated.
Fractures of the radial head
Clinical features
History
Radial head fractures occur frequently, usually as a result of a fall onto an outstretched hand or, less frequently, following a direct blow to the lateral side of the elbow. Radial head fractures present with pain and restricted movement at the elbow.
Examination
Usually there is swelling and tenderness over the radial head. Sometimes, with more subtle injuries, rotating the forearm while palpating the radial head may be necessary to elicit tenderness. Elbow extension and forearm rotation are usually limited. Severely comminuted fractures may involve proximal displacement of the radius, which can be associated with disruption of the interosseous membrane and subluxation of the distal radio-ulnar joint (Essex–Lopresti fracture dislocation).
Clinical investigations
Imaging
Standard anteroposterior (AP) and lateral x-rays of the elbow and, on indication, also of the wrist are required. A radio-capitellar view may be necessary if the fracture is subtle. The presence of an anterior fat pad sign alone on x-ray is associated with an underlying radial head or neck fracture in up to 50% of patients. In this case, a fracture should be assumed to be present if there is an appropriate mechanism and local signs. A follow-up x-ray or CT scan is indicated only in the presence or persistent pain, stiffness or locking.
Classification
Radial head fractures are usually classified according to the (modified) Mason classification ( Fig. 4.4.1 ). About two-thirds of fractures are Mason type I.
The Mason classification is as follows:
-
Mason type I, displaced less than 2 mm
-
Mason type II, displacement more than 2 mm
-
Mason type III, comminuted fractures of the entire radial head
-
Mason type IV, radial head fracture with associated elbow dislocation
Treatment
All non-displaced (type I) radial head fractures and those type II fractures without mechanical block may be managed with a bandage and sling. Mobilization should be started as early as possible. If there is severe pain, a posterior splint may be useful, but it should not be applied for more than 2 days. Prognosis is good, but full extension may not be possible for many months.
Displaced or complex radial head fractures (type II or III) may be treated in the acute setting with a sling or posterior splint. These patients should have early orthopaedic review (within days). The treatment of displaced or complex radial head fractures remains controversial and should be determined by an orthopaedic surgeon.
Mechanical block can be difficult to assess acutely due to pain. Intra-articular injection of bupivacaine may assist early assessment or assessment may be deferred until pain has settled. Surgical options include open reduction and internal fixation and excision of the radial head with or without implantation of a prosthesis.
Radial neck fractures with up to 20-degree tilts can be managed conservatively. Fractures with more severe tilts can be reduced using intra-articular local anaesthesia. The forearm is pronated until the most prominent part of the radial head is felt. Then traction is applied to the forearm and pressure applied to the radial head. Open reduction is indicated if closed methods fail or displacement is severe.
Proximal radial fractures may be associated with rupture of the interosseous membrane and dislocation in the distal radioulnar joint (DRUJ) (Essex–Lopresti fracture). Pain in the wrist should give an index of suspicion; moreover, on the lateral x-ray of the pronated wrist, the distal part of the ulna is usually subluxated to dorsal.
Complications
Neurovascular complications and compartment syndrome are uncommon. Most complications relate to disturbance of the relationships of the proximal radio-ulnar and radio-capitellar articular surfaces, causing limitation of movement. This is uncommon with minor fractures.
Shaft fractures
Clinical features
History
This type of injury requires great force, typically from a motor vehicle accident, a fall from a height or a direct blow. These fractures are commonly open and nearly always displaced.
Examination
The forearm is swollen and tender and may be angulated and rotated. Examination looking for an open wound, local neurovascular compromise, compartment syndrome or musculotendinous injury is required. Given the mechanism of injury, other injuries should also be sought.
You're Reading a Preview
Become a Clinical Tree membership for Full access and enjoy Unlimited articles
If you are a member. Log in here