Scaphoid fracture of the wrist

Scaphoid fracture is the second most common wrist fracture. It is more common in young people. It is associated with sports or car accidents.

Written and verified by the doctor Mariel mendoza on November 18, 2021.

Last update: November 18, 2021

The scaphoid fracture represents between 2 to 7% of the total fractures in the world, being the second most frequent on the wrist and the first between the carpal bones. It occurs mainly in young people and is associated with sports or car accidents.

Its diagnosis is not easy and can be confused with a wrist sprain due to its clinical manifestations. Suspicion is extremely important in view of the fact that the main complications (osteoarthritis and avascular necrosis) are associated with incorrect medical action.

Scaphoid bone anatomy

The scaphoid or lunate bone is the first bone on the outer, lateral, or radial side of the first row of the wrist. The wrist is made up of the furthest part of the two bones of the forearm (radius and ulna) and 8 small bones that make up the carpus.

These eight bones form two rows at the base of the hand. The navicular is just on the external or radial side of the wrist, in contact with the radius, under the thumb. Together with the lunate bone and its articulation with the radius and ulna, they are the bones that are mainly involved with the movement of the wrist.

Its name is derived from the Greek language and means boat, describing its long and curved shape. It can be located in the anatomical space called anatomical snuff box, which is produced by the tendons of the thumb when it is extended.

It is divided into three thirds. The third closest to the radius or proximal, the middle which is called neck and the farthest third that is in contact with the other carpal bones. The blood vessels that enter the distal third are responsible for the nutrition of the bone.

Symptoms of a scaphoid fracture are similar to those of a sprained wrist.


Mechanism of scaphoid fracture

Scaphoid fractures account for 75% to 80% of all carpal fractures in general. They are more common in adolescents and young adults, between 15 and 30 years, due to the mechanism of injury.

They are usually caused by a fall on a hyperextended hand with the joint in dorsal flexion (upward flexion), causing all the weight to fall on the hand and, especially, on the thumb.

It is associated with traffic accidents and sports injuries.

Symptoms can be confused

This fracture is difficult to diagnosesince its only clinical manifestation is usually tenderness in the anatomical snuffbox. There is also swelling and pain on mobilization.

So it can go unnoticed, not be treated properly, and be mistaken for a wrist sprain. It does not cause any obvious deformity and the swelling usually improves with the use of anti-inflammatories.

Scaphoid fracture also affects the range of motion of the wrist, generating difficulty in taking or holding objects, or in moving and turning the wrist and thumb.



Diagnosis of scaphoid fracture

In case of symptoms suggestive of scaphoid fracture (tenderness in anatomical snuffbox) Wrist radiographs are requested in different views: posteroanterior, lateral and in ulnar or ulnar deviation. In some cases, oblique projection with 45-degree wrist rotation is also indicated.

However, if the fracture is not displaced, it can take up to 2 weeks for the lines of evidence to show up on an x-ray. Thus, unless imaging studies can be requested for diagnostic confirmation (magnetic resonance imaging or computed tomography), a clinical diagnosis should be chosen.

When in doubt or due to lack of resources to perform a tomography, for example, it is preferred to immobilize as if there were confirmation of the fracture. The radiographic study is then repeated at 2 weeks.

Initial treatment of scaphoid fracture is conservative

Scaphoid fracture heals slowly and it can take 10 to 12 weeks to cure. For undisplaced fractures, the wrist and thumb are immobilized with a spica cast.

Also, in some cases the use of bone stimulators is recommended. These are devices that apply low intensity pulsed electromagnetic waves to stimulate bone healing.

If there are displaced or undisplaced fractures that do not heal after 6 weeks, surgery is required. The same may consist of screw placement or vascularized bone graft. Other indications for surgery include fractures of the end closest to the radius or proximal, instability, and oblique fractures.

Recovery time depends on the severity of the fracture. Successive consultations, radiological controls are required to monitor the healing process and rehabilitation exercises.

Rehabilitation is a very important part of recovering from fractures. The case of the doll is no exception.

Complications are associated with delayed diagnosis

The complications of scaphoid fractures are varied and are associated with the delay in the use of immobilizations, due to the delayed diagnosis.

Lack of union

If the fracture fragments do not join and heal it is called lack of union. It is common in view of the poor blood supply of the scaphoid bone. Resolution is surgical only and consists of the placement of screws or a bone graft.

Avascular necrosis

In scaphoid fractures, due to its poor blood supply, and especially in displaced fractures with the generation of small fragments, there is a decrease in blood flow that can cause no nutrients to reach the cells and they die.

It is a frequent and disabling complication. It requires surgical resolution by placing a vascularized bone graft.

Arthritis

Over time, nonunion and avascular necrosis can lead to cartilage degeneration in the wrist. This is called arthritis and causes bone-to-bone friction.

The symptoms are pain, stiffness, and functional impotence that does not improve. Treatment is symptomatic, with anti-inflammatories and immobilization.

Recovery from scaphoid fracture depends on each case

Undisplaced fractures, with a timely diagnosis and located in the distal or furthest portion of the radius, They should take 10-12 weeks to heal. However, there are many associated factors that could change this perspective.

Regardless of whether the treatment is surgical or conservative, recovery is slow and requires the use of immobilizers until the injury is consolidated. In addition to the performance of rehabilitation therapy at home.

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