Practice Essentials
Scaphoid fractures are the most common type of wrist fracture, accounting for 10% of all hand fractures and up to 60-70% of all carpal fractures. [1] They frequently occur after a fall on an outstretched hand. Plain radiographs after the initial injury may not reveal a fracture, and a delay in the diagnosis and treatment of a scaphoid fracture can alter the prognosis for union, increasing the risk of avascular necrosis and the long-term likelihood of arthritis. With treatment of scaphoid fractures, either physical or occupational therapy is necessary for regaining strength and range of motion (ROM) in the affected wrist and hand.
Symptoms of scaphoid injury
The patient with a scaphoid fracture often presents complaining of wrist pain and may be diagnosed as having a sprain of the wrist. In sports-related injuries, it is not uncommon for a fractured scaphoid to go unnoticed. Pain and tenderness are often on the radial side of the wrist. Pain often is exacerbated with wrist motion. Edema of the injured wrist is present to some degree and may involve the hand or entire upper extremity.
Workup in scaphoid fracture
When a scaphoid fracture is suggested on physical examination, a scaphoid series (including a posteroanterior [PA] view with the wrist in ulnar deviation) should be ordered, because routine wrist anteroposterior (AP), lateral, and oblique views may not show the fracture. Based on retrospective studies and cadaveric review, the most sensitive radiographic evaluation includes four views: PA, lateral, pronated oblique (60° pronated oblique), and ulnar deviated oblique (also described as 60° supinated oblique). [2, 3]
If a diagnosis cannot be confirmed with confidence on routine films, a technetium-99m (99mTc) bone scan or a magnetic resonance imaging (MRI) scan of the wrist is recommended. [4, 5]
Management of scaphoid fracture
The wrist is always stiff after immobilization for more than a few weeks. Mobilization cannot be started until the injured tissue has healed enough to provide some degree of stability. Active wrist ROM exercises should be started as soon as the cast is removed. Pronation and supination should not be overlooked.
Mobilizing the joint is desirable before the bone and soft tissues have healed completely. Various splints are required to protect and support the wrist in its final stage of healing.
The muscles crossing the wrist must be strengthened after the wrist has healed, edema has been controlled, and motion has improved. Functional activities and progressive resistive exercises are employed. The wrist flexors and extensors are contracted actively against maximum resistance through a full arc of motion.
Indications for immediate surgical referral include the following:
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Fracture of the proximal pole
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Fracture displaced more than 1 mm
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Delayed presentation of acute fracture
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Fracture associated with scapholunate ligament rupture
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Carpal instability (lunate tilt on radiograph)
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Work considerations, when early return is desired in cases of nondisplaced fracture
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Evidence of nonunion or osteonecrosis
Displaced or unstable fractures require percutaneous pin fixation or compression screw fixation to prevent malunion. Internal fixation is accomplished with either smooth Kirschner wires or a Herbert screw. [6]
Related Medscape Drugs & Diseases topics:
Wrist Fracture Management in the ED
Wrist Fractures and Dislocations
Scapholunate Advanced Collapse (SLAC)
Related Medscape resource:
Resource Center Fracture
Pathophysiology
Anatomic considerations
The carpus contains eight small bones, which are arranged in two rows, proximal and distal. The proximal bones, from the radial to the medial side, are the scaphoid, lunate, triquetrum, and pisiform. Only the scaphoid and lunate articulate with the radius; thus, these 2 bones transmit the entire force of a fall on the hand to the forearm. The distal bones are, starting from the radial side, the trapezium, trapezoid, capitate, and hamate. In scaphoid injury, pain is often elicited in palpation of the anatomic snuffbox, which is bordered by the extensor pollicis longus tendon medially, the extensor pollicis brevis and abductor pollicis longus tendons laterally, and the styloid process of the radius proximally.
Blood supply
Anatomically, the scaphoid may be divided into proximal, middle (termed the waist), and distal thirds. The scaphoid is unique in that it is supplied by the palmar carpal branch of the radial artery from the distal to the proximal pole. Fractures of the proximal third of the scaphoid account for 15% of scaphoid fractures, those of the middle portion account for 65%, those of the distal tuberosity account for 10%, and fractures of the distal body make up the remaining 10%. [7] Diminished blood flow to the proximal pole is noted in about one third of fractures at the waist level. Since supply to the proximal pole is tenuous, disruption may result in avascular necrosis. Almost 100% of proximal pole fractures result in aseptic necrosis. Displaced scaphoid fractures have a nonunion rate of 55-90%.
Fall onto outstretched hand
The usual mechanism of injury is a fall onto the outstretched hand (FOOSH) that results in forceful hyperextension of the wrist and impaction of the scaphoid against the dorsal rim of the radius. This mechanism explains why snuffbox tenderness is so common, even in the absence of a scaphoid fracture. Conventional medical wisdom dictates that snuffbox tenderness should be equated with a scaphoid fracture unless radiographs prove otherwise. If initial radiographs do not show fracture, follow-up radiographs should be obtained in 7-14 days, because the fracture line may be more visible after some resorption.
Epidemiology
Frequency
United States
Scaphoid fracture has been reported in people aged 10-70 years, although it is most common in young adult men following a fall, athletic injury, or motor vehicle accident.
Using the National Trauma Data Bank, a study by Wells et al indicated that 286 scaphoid fractures per 100,000 person-years present at US trauma centers. [8]
Mortality/Morbidity
The scaphoid has no ligamentous or tendinous attachments, but joint compressive forces, trapezial-scaphoid shear stress, and capitolunate rotation moments exert control on the scaphoid. Therefore, scaphoid fractures have a high incidence of nonunion (8-10%), frequent malunion, and late sequelae of carpal instability and posttraumatic arthritis.
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A higher incidence of aseptic necrosis and nonunion is noted with fractures of the proximal pole of the scaphoid, due to the blood supply (as detailed above).
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A scaphoid fracture can present as a nondisplaced, stable fracture or as a displaced, unstable fracture. Displaced fractures frequently are associated with ligamentous tears in the wrist and require thorough evaluation and follow-up.
A study by Williams et al using the National Trauma Data Bank found a relatively high rate of concomitant scaphoid and proximal radius fractures in young males. The investigators reported that out of 11,309 patients with proximal radius fracture and an injury severity score of below 15 (with the latter providing a proxy for low-energy injury), 3% had scaphoid fractures. In men aged 18-30 years, however, the incidence of concomitant fractures was 10%. [9]
The aforementioned study by Wells and colleagues indicated that the injuries most commonly associated with scaphoid fractures, as presented at US trauma centers, include distal radius fractures, distal ulnar fractures, and nonscaphoid carpal bone fractures. [8]
Race
No known correlation exists between race and scaphoid fracture.
Sex
Scaphoid injuries are more common in men than in women.
Age
Scaphoid fracture is uncommon in children because the physis of the distal radius usually fails first, resulting in Salter type I or II fractures of the distal radius. Similarly, in elderly patients, the distal radial metaphysis usually fails before the scaphoid can fracture.
Patient Education
The patient should be informed that degenerative arthritis of the wrist is highly likely, but this condition may take years to develop, depending on the amount of chronic stress applied to the wrist.
To help prevent further morbidity, patients can be educated on the basics of wrist injury and how to properly care for their cast or splint. Common symptoms of wrist injury, including pain, swelling, bruising, stiffness, and weakness, can be discussed. In addition, patients can be counseled to monitor for warning signs and symptoms such as numbness and tingling (possible nerve injury), intractable pain (possible avascular necrosis), and redness, swelling, warmth, and tenderness (possible infection).
If the patient is using acetaminophen or nonsteroidal anti-inflammatory drugs (NSAIDs), it is important to recommend adherence to prescribed limits, given the adverse effects associated with increased dosages. Treatment can also be covered, including rest, ice, elevation or elastic bandaging, or, in some cases, surgery. Discussion of proper cast and splint care is warranted, as is determination of a general timeline for the wrist sprain or fracture to heal. Special care should be taken for patients in labor-heavy industries or those whose activities place significant stress on the wrist. If warranted, smoking cessation is encouraged, as active smoking may prolong fracture healing. Appropriate follow-up and aggressive rehabilitation should also be emphasized to the patient.
For patient education information, see the articles Broken Hand and Wrist Injury.
