Scaphoid fracture
X-ray of a healthy hand seen on different views to show the scaphoid carpal bone

Definition

A scaphoid fracture consists of a break of one of the four proximal carpal bones of the wrist located between the radius and the thumb.

The protruding scaphoid bone is easily felt below the thumb base

Pathology

The fracture of the scaphoid is the most common carpal bone fracture reaching 70% due to its protruding anatomy. The scaphoid plays a critical role in the movement of the thumb and in limiting the degree of the movement of the wrist. Its fracture can have serious consequences for the function of the thumb and the entire hand. With a high energy impact a scaphoid fracture may be associated with fractures of other wrist bones or distal ulna and radius.

Three different types of scaphoid fractures are depicted according to the location

Classification

Scaphoid fractures may be non-displaced, when the bone fragments maintain their anatomical position, or displaced when the bone fragments have moved from their original anatomy. They also adopt names depending on the location of the break: tubercle, waist and proximal fracture. A scaphoid fracture may occur in association with a distal radius fracture.

Left: Distal radius intraarticular, displaced fracture; Middle: Older distal radius fracture with callus formation; Right: Distal radius and ulna fracture, extraarticular and displaced

No 2.

Intra-articular fracture extends to the wrist joint (or articulation)

Extra-articular fracture is located outside of the wrist joint

Open fracture when bone fragments perforate the skin

Comminuted fracture when the bone breaks into multiple fragments

Non-displaced when the anatomical alignment of the bone is maintained or displaced when the bone fragments move apart.

Melone’s classification describes the characteristics of intra-articular fractures of the radius:

i    Stable fracture

ii    Unstable "die-punch"

iii   "Spike" fracture

iv Split fracture

v   Explosion injuries

Acetabular fracture of the pelvis

Acetabular fractures

These fractures are divided into:

Anterior pillar (not weight bearing part of joint)

Posterior pillar (often associated with dislocation of the hip including the weight bearing part of joint)

Transverse

Comminuted involving both column type 

Sacral / coccygeal fractures

The sacrum is a triangular-shaped bone formed by 5 fused vertebrae, which provide a posterior wall to the pelvic ring. At each side of the sacrum, the ala structures articulate with the ilium bones forming the sacro-iliac joints. Sacral fractures are usually parallel to the spine and can involve the ala. Less frequently sacral fractures may display an “H” shape, including a transversal fracture uniting both sides of the sacrum. Three zones are described where sacral fractures can occur that are along vertical lines relative to the alignment of the foramina. Sacral fractures may result in sacral instability and require treatment via sacroplasty (injection of bone glue into the fracture). Surgery is necessary in case of associated neurological symptoms.

Fractures of the coccyx involve the tailbone, the terminal portion of the spine situated below the sacrum formed by 3 to 5 fused vertebrae. Coccyx fractures occur when falling on a seated position. They are more common in elderly women and seldom require surgical treatment.

Falling on the outstretched hand is a typical mechanism to a scaphoid fracture

Causes

The main cause of scaphoid fracture is a fall on the outstretched hand on the open palm. It also occurs in motor vehicle and sport accidents with high frequency in men between 15 and 30 years of age. Scaphoid fractures are common in older people due to their weaker balance.

The predisposition to fall in older individuals poses a risk to a scaphoid fracture

Risk factors

Prominent risk factors for a scaphoid fracture include participation in intensive sport activities in the younger population particularly in adolescents and young men, and low energy falls in the elderly. Additional risk factors include: 

Sport (Basketball, football, rugby, hockey, skiing, snowboarding)

Medical conditions (osteoporosis, menopause)

Smoking (reduces calcium absorption and predisposition to fractures)

Image showing the "snuff-box" where pain is felt following a scaphoid fracture

Symptoms

The symptoms arising from a scaphoid fracture are:

Sharp pain at thumb base and wrist

Pain at the ‘snuff box’ exacerbated with grip

Swelling at the base of the thumb

Deformity of the wrist

Bruising

Stiffness/inability to move the thumb

X-ray of a fractured scaphoid. Note the fracture line indicated by the red line

Diagnosis

The examination begins with the patient’s medical history including previous wrist dislocations and injuries. As pain diminishes within a day or two from the incident, a fracture to the scaphoid can be easily overseen. Clinical examination of the wrist will determine:

Changes in the anatomy of the affected wrist against the healthy wrist

Tenderness when applying gentle pressure on the ‘snuffbox’

Pain when applying pressure on the inner side of the wrist while extending the wrist joint (specific test for scaphoid fracture)

X-rays are taken when a fracture of the scaphoid is suspected. However, this method does not always reveal the presence of a fracture. This can become visible on X-rays during the healing process of the fracture after 1-2 weeks. During this period the patient wears a splint on the wrist. Compared to X-rays, and CT scans, MRI images offer a more sensitive alternative for the detection and accurate characterisation of scaphoid fractures.

Treatment

A brace is a commonly used for conservative treatment of a scaphoid fracture

Nonoperative treatment

The management of scaphoid fractures varies in relation to the fracture site. In case of a fracture in the lower portion of the scaphoid surgery is not required and treatment with a cast or brace is sufficient. The cast is placed either below the elbow including the thumb, or beyond the elbow. Additional conservative treatments include:

Ice pads

Administration of NSAIDs

Painkillers

Physiotherapy whilst the arm is in a cast or brace

A screw was used for internal fixation of the fractured scaphoid

Surgical treatment

Surgical treatment is required in significantly displaced fractures of the scaphoid or following the diagnosis of a nonunion from an older, untreated fracture. Internal fixation is achieved in displaced fractures using special screws and wires after an incision is made either on the back or the palmar side of the wrist. The size of the incision varies depending on the level of break of the scaphoid. A bone graft may be used if the scaphoid is comminuted in several parts. Internal fixation will accelerate the healing process and allow a faster return to sports and other activities.

When a scaphoid fracture presents complications, such as bone necrosis, surgery involves the removal of the dead tissue and the replacement with a bone graft taken from the wrist or the pelvis. This procedure also includes sprouting of vessels into the grafted bone to allow optimal blood supply and healing. The recovery time after a bone graft can last for several months of cast treatment. Ultrasound and electromagnetic waves can support the bone healing process.

Complications

Complications following a fracture of the scaphoid include:

Non-union especially with delayed treatment

Non-union when blood supply to the scaphoid through the radial artery is reduced causing scaphoid avascular necrosis. This is detected with X-rays months after injury and requires surgical treatment

Wrist arthritis caused from the non-union of a scaphoid fracture resulting in chronic pain and restricted wrist movement

Infection after surgery

Flexion extension exercise of the wrist help to recover following a scaphoid fracture

Rehabilitation

Regardless of the type of treatment, a cast or splint is usually worn for 9-12 weeks or up to 6 months. Any physical activities that increase the risk of a fall should be avoided until complete fracture healing has been achieved. To prevent stiffness, it is critical to maintain finger movement and begin physical therapy soon after the fracture has healed or generally 6-8 weeks after surgery. A physical or occupational therapist assists with exercises to restore flexibility and strength of the wrist including fine movements of the hand and fingers. A guided educational program will educate the patient how to modify activities to avoid recurrent injuries to the wrist. Standard rehabilitative therapy also includes:

Hand elevation (to reduce swelling/pain)

Pain management with analgesics

Antiinflammatory treatment with NSAIDs

Ice or heat pads

Massage

Joint mobilisation

Stretches

Electrotherapy

Return to activity plan

Wearing reinforced gloves can prevent hand and wrist injuries

Prevention

The main preventative measures for a scaphoid fracture aim at reducing the risk of falls and protect the wrist if collisions occur during sport, cycling and motor biking. Common strategies are:

Postural taping

Wearing protective gear during work recreational activities

Osteoporosis treatment

Use of devices to improve elderly patient stability and avoid falls

Modification of physical activities

Exercise to improve muscle strength, flexibility and posture