Distal radius fracture

Distal radius fractures are a very common injury of the radius that occur at the distal end, where the wrist joint lies.

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Definition

A fracture affecting the distal end of the radius and often the ulnar styloid. Because of its close proximity to the wrist joint this injury is often called a wrist fracture.

Synonyms

Wrist fracture; fractured wrist; Colles' fracture; Smith's fracture; Barton's fracture; Chauffeur's fracture (so called because the crank used to start old cars often kicked back and broke the chauffeurs' wrists with a particular pattern). Most of these names are applied to specific patterns of distal radius fracture but confusion exists because "Colles' Fracture" is used (for example by the US National Library of Medicine[1]) as a generic term for distal radius fracture.

Incidence

This is the most commonly occurring fracture in adults. Common fragility fracture in the elderly. Also a common injury in children where it may involve the growth plate. A similar fracture in children involving the growth plate is called a Salter Harris Fracture. It is less common in young adults but because it requires greater force, the injury is often very severe in this age group.

Pathogenesis and predisposing factors

The most common cause of this type of fracture is when an individual falls on an outstretched hand (acronym: FOOSH).^[1] In young adults it is the result of moderate to severe force. The risk of injury is increased in patients with osteoporosis and other metabolic bone diseases.

Clinical features

History

Patients usually present with a history of an injury and localized pain. They frequently also notice deformity of the wrist and swelling. Numbness of the hand can occur. Inability to use the hand is also common.

Examination

Deformity, tenderness and loss of wrist motion are normal features on examination of a patient with a distal radius fracture. Swelling is common. Broadening of the wrist can be perceived. Radial styloid and ulnar styloid may be at the same level. Examination should rule out a skin wound which might suggest an open fracture, loss of sensation or loss of circulation to the hand.

Injuries associated

Scaphoid fracture; wrist dislocation. Injuries to the elbow, humerus and shoulder are also common after a FOOSH (fall on out-stretched hand). Swelling and displacement can cause an acute carpal tunnel syndrome.

Diagnosis

Diagnosis may be evident clinically when the distal radius is deformed but should be confirmed by x-ray.
Differential Diagnosis includes scaphoid fracture and wrist dislocation which can also co-exist with a distal radius fracture.

Investigation

X-ray of the affected wrist is required if a fracture is suspected. CT scan is often performed to investigate the exact anatomy of the fracture, especially if surgery is considered. Investigation of a potential distal radial fracture includes assessment of the lateral articular angle, radial length, and articular surface.

Lateral articular angle

The lateral articular angle is the angle between the axis of the radius and the articular cup. This angle is measured on x-ray films. Normally, the angle is turned down toward the thumb (volar tilt) by 11°. As pressure is applied to the radius, the cup may become aligned differently. Alignment up to 0° is still considered to be functional, and does not require any intervention. However, tilt away from the thumb (dorsal tilt) beyond this point (>11° deviation) requires reduction of the fracture. When dorsal tilt beyond the acceptable threshold occurs, distal radio-ulnar joint motion is altered, and forearm rotation becomes restricted. The upper limit of an acceptable deformity after reduction of the fracture is 5° of dorsal tilt.

Radial length

Radial length is one of the important considerations in a distal radius fracture. The core question that must be answered is "is it short?" The radius length would be too short if there is greater than neutral variance, especially when compared to the opposite side of the body. If the radial length remains uncorrected, ulnar impaction syndrome may occur.

Articular surface

Any articular joint surface must be smooth for it to function properly. The surface is not smooth if there is more than 1 mm step deformity, and is associated with posttraumatic arthrosis. Irregularity may result in radiocarpal arthritis, pain, and stiffness. If the surface is very irregular, the optimal treatment is fusion.

Classification

In medicine, classifications systems are devised to describe patterns of injury which will behave in predictable ways, to distinguish between conditions which have different outcomes or which need different treatments. Most wrist fracture systems have failed to accomplish any of these goals and there is no consensus about the most useful one.

OTA system

The Trauma Association classification is widely accepted and under constant review. (More details available here.)

• (21-A) Extra-articular
  • (21-A2) Radius only
  • (21-A3) Radius and ulna
• (21-B) Articular fracture involving articular surface of only one of the two bones
  • (21-B2) Radius fractured, ulna intact
  • (21-B3) Articular of one bone, extra-articular of other
• ((21-C) Articular fracture involving articular surface of two bones
  • (21-C2) Simple of one, multifragmentary of other
  • (21-C3) Multifragmentary of both

Details on further levels of subcoding are available here (warning: PDF).

Other systems

The images from this system illustrate how varied the injury can be. Wheeless details several classification systems, but comments "the classification does not include extent or direction of initial displacement, dorsal comminution, or shortening of the distal fragment; - hence, it is less useful in evaluating the outcome of treatment". These systems include:

• Frykman
• Melone
• Universal. Universal codes include:
  • Type I: extra articular, undisplaced;
  • Type II: extra articular, displaced;
  • Type III intra articular, undisplaced;
  • Type IV: intra articular, displaced;

General features

Although there is no formal scientific classification based on them, there are three features of the fracture that relate to outcome and to each other:

• stability of the fracture
• displacement (especially of the joint surface)
• how severe the injury to the joint is

At one extreme a stable, undisplaced extra-articular fracture has an excellent prognosis. On the other an unstable, displaced intra-articular fracture is difficult to treat and has a poor prognosis.

Natural history/untreated prognosis

Nonunion is rare; most of these fractures heal. However, if the fracture is unstable the deformity at the fracture site will increase and cause limitation of wrist motion and forearm rotation, pronation and supination. If the joint surface is damaged and heals with more than 1-2 mm of unevenness the wrist joint will be prone to post traumatic osteoarthritis.

Non-operative treatment

Where the fracture is undisplaced and stable, non operative treatment involves splinting the fracture, often in a cast. In displaced fractures, the fracture may be manipulated under regional or general anaesthesia and casted in a position to minimize the risk of re-displacement. The general principle is to reverse the mechanism of injury. A FOOSH will usually cause over-extension of the wrist joint, often with some radial deviation. Therefore, the preferred position for this type of injury, following reduction, is flexion and ulnar deviation.
During the period of follow-up, it is common practice to repeat x-rays at about 1 week to make sure the position is still acceptable. Follow-up is also needed to determine when the cast may be removed, when the fracture has healed and when rehabilitation is complete.
The length of time in the cast varies with different ages. Children heal more rapidly, but may ignore activity restrictions. Three weeks in a cast and 6 weeks off sports is often appropriate for them. In adults, the risk of stiffness of the joint increases the longer it is immobilised. If callus is seen on x-ray at 3 weeks, the cast may be replaced by a removable splint. However, many orthopaedic surgeons leave the patients in the cast for up to 6 weeks.
Following healing and cast removal a period of rehabilitation for recovery of strength and range of motion is necessary.

Risks of non-operative treatment

Failure of non-operative treatment is common and is the largest risk of an adverse outcome. Studies have shown [2] that the fracture often re-displaces to its original position even in a cast. Earnshaw et al[3] showed only 27% - 32% of fractures were in acceptable alignment 5 weeks after closed reduction. Long term this increases the risk of stiffness and post traumatic osteoarthritis leading to wrist pain and loss of function.
Other risks specific to cast treatment relate to the potential for compression of the swollen arm causing compartment syndrome or carpal tunnel syndrome. Reflex sympathetic dystrophy is a serious complication following injury and is thought to be more common after cast immobilisation than after surgery. The provoking factors for Regional Pain Syndromes, however, are very complex.
Stiffness is universal following a prolonged period of immobilization and swelling. In some cases it does not fully recover. Rehabilitation after cast treatment often takes longer to accomplish a return of acceptable function.

Prognosis following non-operative treatment

In children the outcome of distal radius fracture treatment in casts is usually very successful with healing and return to normal function expected. Some residual deformity is common but this often remodels as the child grows.
In the elderly, distal radius fractures heal and may result in adequate function following non-operative treatment (reduction and casting). A large proportion of these fractures occur in elderly people with limited expectations and little requirement for strenuous use of their wrists. Some of these patients tolerate severe deformities and minor loss of wrist motion very well and would not have improved their status significantly had they had exact reduction of their fracture.

On the other hand, in younger patients the injury requires greater force and is result in a worse fracture pattern involving the joint. Unless accurate reduction of the joint surface is obtained these patients are very likely to have long term symptoms.

Management

Closed management of a distal radius fracture involves first anesthetizing the affected area with a hematoma block, regional anesthesia, sedation or a general anesthetic.

Manipulation generally includes first placing the arm under traction and unlocking the fragments. The deformity is then reduced with appropriate closed manipulations (depending on the type of deformity) reduction, after which a splint or cast is placed and an X-ray is taken to ensure that the reduction was successful. The cast is usually maintained for about 6 weeks.

Closed treatment is frequently unsuccessful in maintaining a good position in adults, because there is frequently comminution of the fracture. Re-displacement and deformity can reoccur with an unacceptable ultimate result.

Contemporary surgical options have developed that really have revolutionized treatment of this common injury. Generally, techniques include Open Reduction Internal Fixation (ORIF), external fixation, percutaneous pinning, or some combination of the above. The greatest recent advances have been with operative open reduction and internal fixation ORIF. A entire market of surgical implants are available to treat this specific fracture. The two most recent and promising developments have been fragment specific fixation and fixed angle volar plating. These attempt fixation rigid enough to allow almost immediate mobility, thus ultimately less stiffness and greater function is possible. Although restoration of radiocarpal alignment is of obvious importance, one must not overlook the alignment of the distal radioulnar joint as this can be a source of a frustrating pronation contracture down the road.

Each orthopaedic surgeon will treat the fracture according to what his/her preferences are and what works best for him/her. The surgeon should be open to discussion of the rationality of the decisions that are made.

Prognosis varies depending on dozens of variables. If the anatomy (bony alignment)is not properly restored, function may remain poor even after healing. Restoration of bony alignment is not a guarantee of success, as there are significant soft tissue contributions to the healing process.

An arthroscope can be used at the time of fixation to evaluate for soft tissue injury. Structures at risk include the triangular fibrocartilage complex and the scapholunate ligament. Be ware of scapholunate injuries in radial styloid fractures where the fracture line exits distally at the scapholunate interval. TFCC injuries causing obvious DRUJ instability can be addressed at the time of fixation.

References

External resources

• Orthopaedic Trauma Association Fracture Classification Radius and Ulna
• Wheeless' Textbook of Orthopaedics Fractures of the Radius
• Wheeless' Textbook of Orthopaedics Closed Reduction of Distal Radius Fractures - Good account and list of references.
• NLM MeSH entry on Colles' Fracture
• Distal radius fractures
• [4] Patient Education Page
• [5] Broken Wrist Page, written for the Patient Education website for the American Academy of Orthopedic Surgeons