Forearm fractures are very common in young active adults. These fractures generally include at least one or both of the forearm bones namely radius or ulna.
Forearm has two bones radius and ulna. They articulate at elbow and wrist with each other and other bones to form part of elbow and wrist joints. Forearm fracture involves the fracture of shaft of ulna or radius or both bones. On most of the occasions, both bone fracture together. In case of single bone fractures, the proximal or distal joint might be injured.
It is uncommon for a single bone to be injured without any associated injury to other bone or either joint.
The forearm is a complex anatomic structure and a very important part of the upper extremity.
Malunion [shortening and angulation] can cause many problems of the function of the upper limb.
Therefore, precise reduction for anatomical restoration and secure fixation is very necessary in forearm fractures.
Relevant Anatomy of Forearm Bones
The radius and ulna are two bones of the forearm and come into contact with each other only at the ends. They connect proximally at the elbow joint and distally at radioulnar joint.
Ulna bone is relatively straight bone. It articulates with the distal humerus at the elbow and runs virtually subcutaneously distally to the ulnar styloid at the wrist.
The other bone, the radius is bowed. Its articulation with capitellum of humerus angles at least 13° opposite to the bow.
Radial bow and interosseous space must be preserved for normal motion of forearm.
Mechanism of Injury of Forearm Fractures
Forearm fracture can be caused by various mechanisms. The most common is motor vehicle injury especially automobile and motorbike injuries. Most of these vehicular accidents result in some type of direct blow to the forearm.
Direct trauma by an object such as stick etc also can cause the fracture of these bones.
Gunshot wounds can cause forearm fracture. Such injuries are commonly associated with nerve or soft tissue deficits and frequently have a significant bone loss.
Another cause is pathological forearm fracture and in such cases, a previous underlying pathology is responsible for the injury. This injury can result from trivial trauma, a force which normally would not cause a break in the normal bone.
Forearm fracture can occur as a result from fall too as in fall from heights.
Clinical Presentation of Forearm Fractures
In adults, it is very rare for these fractures to be undisplaced. As radius and ulna are strong bones, an injury of sufficient force is required to break them which would cause displacement.
After forearm fracture, the patient usually presents with a history of significant trauma which results in pain, swelling, deformity, and loss of associated function of the forearm. Often the displacement is significant enough to make a clinical diagnosis. Level of the deformity or level of tenderness in case of undisplaced fractures tells about the level of the fracture.
Presence of wound is likely to make the fracture open. Therefore any wound, especially near the fracture site, should be examined for communication with fracture hematoma. A careful neurologic evaluation of the motor and sensory functions of the radial, median, and ulnar nerves should be done. Amount Distal pulses should be palpated to check for the vascular status of the forearm.
Swelling of the forearm should be assessed to rule out compartment syndrome. A simple clinical test to diagnose a compartment syndrome is a passive stretch of the fingers. If the pain in the forearm is present when the fingers are passively extended, a compartment syndrome is probably present.
If the patient is noncooperative or unconscious, compartment pressures should be measured to rule out the possibility of compartment syndrome.
A simple anteroposterior and lateral radiograph of the forearm would help to diagnose the fracture pattern and the level of forearm fracture. Wrist and elbow joints should be included in the radiographs to rule out any associated injury.
The configuration of midshaft fractures of the radius and ulna varies depending on the mechanism of injury and the degree of violence involved.
Low-energy fractures tend to be transverse or short oblique, whereas high-energy injuries are comminuted or segmented and are often associated with extensive soft tissue injuries.
A line drawn through the radial shaft, neck, and head should pass through the center of the capitellum on any radiographic view of the elbow. This simple test can determine any associated elbow injury.
In case of doubtful wrist and elbow injuries computed axial tomography can be undertaken to look for subtle injuries. It is better to involve the normal part of the opposite limb for comparison.
Treatment of Forearm Fractures
Forearm fracture can be treated with various options. These vary from cast immobilization, plate fixation, intramedullary nailing to external fixation with each of them having an appropriate indication.
The basic principle behind the treatment is an accurate anatomic reduction, rigid fixation, and early mobilization of the soft tissues.
Majority of displaced fractures of the shafts of the radius and ulna are treated by the operative method. Closed treatment of forearm fracture should be undertaken only if there is a specific contraindication to operative treatment. Nondisplaced fractures of the shafts of both the radius and the ulna are very rare in adults.
Simple cast immobilization is used in undisplaced fracture of both bones of the forearm in adults. However, this entity is very rare in adults.
Following cast application, x-rays should be done at weekly interval. It is very common for these fractures to become displaced later, therefore they should be watched. In case the displacement occurs, it should be treated as a displaced fracture.
Displaced fractures of forearm do not yield satisfactory results with closed treatment and should be operated whenever possible.
Operative treatment allows for accurate fracture reduction and secure fixation.
To achieve excellent results, anatomical reduction and stable fixation are required. Restoration of normal bone length will prevent subluxation of either the proximal or distal radioulnar joint and will reestablish length to the muscles. Restoration of rotational alignment is essential for normal pronation–supination function of the forearm.
Open reduction and internal Fixation using plate fixation is the standard treatment for closed, displaced fractures of the forearm. These fractures of both bones of the adult should be fixed as soon as feasible preferably within the first 24 to 48 hours of injury because the fractures lying in liquid hematoma are easier to reduce and fix.
But these fractures should be fixed any time irrespective of the delay for whatsoever reason.
Most of the fractures of both bones of forearm i.e. radius and ulna are treated by operative methods as nonoperative methods are not very successful especially in displaced fractures.
For closed fractures of these bones, the surgery is either fixation with plate and screws or intramedullary nailing.
Stainless steel, limited-contact, the dynamic compression plate is the treatment of choice for displaced fractures of the radius and ulna and provide very good results.
The preferred plate is the eight-hole dynamic compression plate with 3.5-mm cortical screws.
Though plate and screw combination takes care of most of the fracture configurations, there are some situations like open fractures, segmental fractures, failed plating and multiple injuries where nailing might be preferred.
The disadvantage of the plating is extensive soft tissue dissection and periosteal stripping. The advantage is the ability of the surgeon to reduce and fix fractures in anatomical position.
Fixation with intramedullary nails is a poor implant as compared to plating and should be reserved for selected indications. The anatomical reduction is of paramount importance in these fractures and that is difficult to achieve with nails.
External fixators are used in case of open injuries or massive soft tissue loss.
Open forearm fractures require emergency treatment. The treatment needs to be individualized depending upon patient profile and wound.
Complications of Forearm Fracture
The complications associated with forearm fracture can be due to injury per se, failure to get the right treatment or complication of treatment as such. Many complications are general complications associated with any fracture and few are specific to these fractures.
Here is a list of most common complications of these fractures.
- Nerve Injury
- Vascular Injury
- Compartment Syndrome
- Posttraumatic Radioulnar Synostosis
- Muscle and Tendon Entrapment and Adherence
- Soft Tissue Contracture
- Subluxation/dislocation of the distal radioulnar joint in Galeazzi fracture
- Radial head instability in Monteggia fracture dislocation
Special Forearm Injuries
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