Fractures of the carpal bones constitute approximately 6% of all fractures, but they are probably underdiagnosed. Scaphoid fractures are the most common fractures of carpal bones, accounting for more than 60% of all carpal injuries. The complex anatomy of the wrist often makes diagnosis and treatment difficult. Overlooking a fracture or dislocation of a carpal bone can result in major complications and prolonged morbidity, so the clinician must maintain a high index of suspicion in the evaluation of wrist injuries.
See Appendix for stepwise instructions for short-arm and long-arm casts and splints used in the treatment of carpal fractures.
Go to Expert Consult for the electronic version of a patient instruction sheet named “Broken Hand or Wrist,” which covers the steps of care from pain relief to rehabilitation exercises. This can be copied to hand out to patients to assist them during the treatment period.
Scaphoid Fractures (Adult)
Anatomic Considerations
The scaphoid lies at the radial aspect of the wrist and links the distal and proximal carpal rows ( Fig. 5-1 ). The scaphoid is tethered to the proximal carpal row by strong volar ligaments: the radioscaphoid, scapholunate, and scaphocapitate. The scaphoid has a central indentation at its waist, which is crossed by the palmar radiocarpal ligament. The scaphoid serves as the principal bony block to excessive extension at the wrist and is therefore susceptible to fracture.
The blood supply to the scaphoid arises distally from branches of the radial artery ( Fig. 5-2 ). The distal tuberosity of the scaphoid receives its blood supply from the anterior interosseous artery, and the proximal pole is completely dependent on the distal blood supply. Because of the vascular anatomy, fractures in the middle and proximal portion of the scaphoid are prone to nonunion at the fracture site and an increased incidence of avascular necrosis (AVN) of the proximal fracture fragment.
Mechanism of Injury
Scaphoid fractures are caused by two common types of injury: a longitudinally directed axial load, which usually results in a stable nondisplaced fracture, and a fall on the extended wrist, which places a tensile force at the volar scaphoid and a compressive force at the dorsal scaphoid.
Clinical Presentation
The patient reports the typical cause of injury, either an axial load to the wrist or a fall onto the extended wrist, and wrist pain. During physical examination, swelling is usually not present except in cases of fracture-dislocation. Wrist range of motion (ROM) is only slightly reduced, but pain is reproduced at the extremes of flexion and extension. Scaphoid compression tenderness, elicited by holding the patient’s thumb and applying pressure along the axis of its metacarpal, is an accurate indicator of a scaphoid fracture. Point tenderness can be elicited at one of three common fracture locations: in the anatomic snuffbox (waist fracture); in the anatomic snuffbox with the wrist in ulnar deviation (distal tuberosity fracture); or just distal to Lister’s tubercle, a small longitudinal bony prominence on the dorsal distal radius in alignment with the third metacarpal (proximal pole of the scaphoid). The tendons of the anatomic snuffbox are best demonstrated when the thumb is extended and the wrist is in a neutral position ( Fig. 5-3 ).
Scaphoid fractures are often accompanied by unrecognized associated injuries. The same mechanism of injury may cause fractures of the distal radius, lunate, or radial head. Also, patients with scaphoid fractures may report symptoms suggesting injury to the median nerve, such as paresthesias of the palmar aspect of the thumb and second and third fingers.
Imaging
Familiarity with the normal radiographic anatomy of the carpal bones assists the primary care provider in recognizing scaphoid fractures. The normal posteroanterior (PA) view of the wrist is shown in Fig. 5-4 . Because of the similarity of their names, the positions of the trapezium and trapezoid are difficult to remember. Recalling that the trapezium articulates with the thumb may help in identifying these carpal bones. The three lines of Gilula should be found ( Fig. 5-5 ). Disruption of one of these lines should alert the primary care provider to a fracture or carpal dislocation. On the lateral view of the wrist, the distal radius, lunate, and capitate line up along a longitudinal axis. The scapholunate angle is usually about 45 degrees, although a range of 40 to 60 degrees is considered normal ( Fig. 5-6 ). Angles of more than 60 degrees indicate carpal instability and fracture displacement ( Fig. 5-7 ).
If a scaphoid fracture is suspected, PA, lateral, and motion views (flexion–extension, radial deviation–ulnar deviation) of the wrist are recommended. Radiographs of the scaphoid often show no abnormalities in the acute setting, and negative radiograph results do not exclude the possibility of a scaphoid fracture. Fractures can be subtle and apparent on only one view ( Fig. 5-8 ).
Fractures of the middle (waist) of the scaphoid are the most common (80%), followed by fractures of the proximal pole (15%), fractures of the distal tuberosity (4%), and fractures of distal articular surface (1%) ( Figs. 5-9 and 5-10 ). The fracture may be stable or unstable; this is important because the rate of union and treatment options vary widely between stable and unstable fractures. A stable fracture is usually caused by impaction, is nondisplaced, has an intact cartilage envelope, and demonstrates incomplete separation of the two fragments. An unstable fracture is usually caused by a fall on the extended wrist, and demonstrates stepoff or angulation of 1 mm or more. Fractures of the scaphoid may be acute or a newly noted old fracture. An acute fracture shows a single fracture line, some degree of dorsal–radial comminution, and possibly dorsal angulation. A newly noted old scaphoid nonunion may show resorption at the fracture site (i.e., separation between fragments), cystic changes, subchondral sclerosis, and displacement on both PA and lateral views ( Fig. 5-11 ).
Radiographs should be examined for signs of ligament disruption and scapholunate dissociation, which can occur after a similar mechanism of injury. A gap of more than 2 mm between the scaphoid and lunate indicates a ligament disruption and is called the “Terry Thomas or David Letterman sign,” named after celebrities who had a prominent space between their front teeth. This finding is best appreciated on a PA view of the slightly flexed fist ( Fig. 5-12 ). Scapholunate dissociations are discussed separately at the end of this chapter.
Several clinicians have advocated use of magnetic resonance imaging (MRI) or computed tomography (CT) scan early in the evaluation of patients with clinical scaphoid fracture (trauma mechanism, snuff box tenderness, swelling) to avoid under- and overtreatment. In addition to difficulty diagnosing scaphoid fractures, detecting displacement of 1 mm or more can be challenging on standard radiographs. Because missed fractures and missed displaced fractures can lead to significant morbidity, it is reasonable to consider early advanced imaging in cases of suspected scaphoid fracture, especially in an athlete or laborer who would benefit from a more timely diagnosis. A bone scan also can be used 72 hours after the injury, but the lower specificity of bone scintigraphy has led to lower use of this modality.
Indications for Orthopedic Referral
Patients with scaphoid fractures should be referred to an orthopedist if the fracture is displaced or angulated, if a nonunion develops after an adequate course of conservative therapy, or if AVN or scapholunate dissociation is suspected. Because of the higher risk of nonunion and AVN, the primary care provider should refer the patient for an orthopedic consultation or referral even for nondisplaced scaphoid fractures because surgical management is often indicated (see below).
Initial Treatment
Table 5-1 summarizes management guidelines for suspected and nondisplaced scaphoid fractures.
| initial treatment | |
| Splint type and position |
|
| Initial follow-up visit |
|
| Patient instruction |
|
| follow – up care | |
| Cast or splint type and position |
|
| Length of immobilization |
|
| Healing time |
|
| Follow-up visit interval |
|
| Repeat radiography interval |
|
| Patient instruction | Maintain finger, elbow, and shoulder ROM during immobilization |
| Indications for orthopedic consult |
|
The amount of swelling initially present after a scaphoid or suspected fracture is usually minimal. Therefore, a cast rather than a splint can usually be applied during the first visit. If the amount of swelling is moderate, a splint or bivalved cast should be used for immobilization.
Suspected Fracture with Radiographs That Show No Abnormalities
Studies support acute MRI as more cost-effective than empiric immobilization with normal radiographs. If MRI is not used for definitive diagnosis and fracture is still suspected, the patient is placed in a short-arm thumb spica cast or splint for 2 weeks. The wrist should be placed in slight extension to prevent limited ROM when the cast is removed. The thumb is slightly extended and abducted, as if the patient is holding a small glass upright. The thumb interphalangeal (IP) joint should be free (i.e., the cast should end proximal to the flexure of the thumb IP joint). The first follow-up visit should be in 2 weeks.
Nondisplaced Fracture
Recent meta-analyses have found no significant differences in long-term function or radiologic healing between patients with nondisplaced waist fractures treated conservatively or surgically. However, more rapid return to work or sport about six weeks sooner can be achieved with surgical fixation of waist fractures. This may be especially important in persons who require earlier return to sport or occupation or those who cannot tolerate prolonged casting.
Evidence to determine the ideal cast length is limited, but if nonoperative treatment is chosen, patients with a nondisplaced fracture of the middle third or proximal third of the scaphoid may have improved healing times when treated in a long-arm thumb spica cast as opposed to a short-arm spica cast. The elbow should be flexed to 90 degrees, the forearm in neutral pronation-supination, the wrist in slight extension, and the thumb in slight extension and abduction. The cast extends from the deltoid insertion on the arm to the proximal palmar crease on the palm. See the Appendix for stepwise instruction for how to apply a long-arm spica cast. A short-arm thumb spica cast can be used for a nondisplaced fracture of the distal third of the scaphoid. Early consultation with an orthopedist should be considered for proximal fractures because of the risk of nonunion or AVN. The patient should be reevaluated within 1 to 2 weeks.
Displaced Fracture
A displaced fracture of the scaphoid should be immobilized in a long-arm thumb spica cast or splint. The patient should be referred promptly to an orthopedic surgeon.
Follow-up Care
Suspected Fracture with Radiographs That Show No Abnormalities
The patient should be reexamined with the wrist out of the cast after 7 to 10 days of immobilization. Repeat radiographs may demonstrate a fracture because immobilization has allowed demineralization of the fracture line. Patients with no tenderness in the anatomic snuffbox and radiographs that show no abnormalities at the time of the second visit can be dismissed safely. Patients whose radiographs appear normal but who have persistent point tenderness or scaphoid compression tenderness should either continue immobilization for 1 more week or have advanced imaging (CT scan, MRI or bone scan) to completely diagnose the injury. Patients with persistent tenderness and negative radiographs at 3 weeks from injury should be imaged with CT scan, MRI, or bone scan. Immobilization should continue as outlined for nondisplaced fractures if a fracture is present. Consultation with a hand specialist should be considered if the patient is still symptomatic and no fracture is seen with advanced imaging by 3 weeks after the injury.
Nondisplaced Fracture
The average duration of immobilization varies by fracture site: 4 to 6 weeks for distal tuberosity and distal third fractures, 10 to 12 weeks for middle third fractures, and 12 to 20 weeks for a proximal third fracture. If a long-arm cast is used initially, it should be continued for at least 6 weeks followed by a short-arm cast until the fracture is healed. Out-of-cast radiographs should be obtained every 2 to 3 weeks until evidence of radiographic union is present. If fracture healing is uncertain, CT scan or MRI should be used to confirm union. During each visit, patients should be encouraged to maintain active ROM of the fingers, thumb IP joint, and shoulder.
Return to Work or Sports
Because treatment of scaphoid fractures requires lengthy immobilization, wrist stiffness and forearm muscle atrophy are likely after the cast is removed. Referral to a physical therapist or occupational therapist is strongly encouraged to help the patient regain motion, strength, and function after cast immobilization. For athletes, the wrist should be protected in a rigid splint for sports activities until strength is 80% of the uninjured side and ROM is normal or near normal. The wrist should be protected for a minimum of 3 months after cast removal.
Complications
A concerning complication of scaphoid fractures is nonunion, which results from the precarious nature of the blood supply and movement at the fracture line. Incidence rates vary by fracture location and treatment but have been estimated to be approximately 10%. Nonunion may be more common in missed scaphoid fractures with a delay in treatment. In the long term, nonunion of a scaphoid fracture can lead to wrist arthritis. If a nonunion develops, the patient should be referred to an orthopedist. Often a further course of conservative therapy is attempted, but if it is unsuccessful, operative fixation, bone grafting, or both may be required.
Another serious complication is the development of AVN ( Fig. 5-11 ). AVN is caused by interruption of the blood supply to the healing scaphoid and is strongly influenced by the anatomic site of the fracture line. AVN is estimated to occur in 13% to 50% of cases with the highest incidence in proximal fractures. The incidence of AVN can be reduced by early recognition and proper immobilization of suspected scaphoid fractures, but it may occur even in cases managed appropriately. AVN results in destruction of the proximal fracture fragment, and this in turn causes significant arthritis of the wrist. Patients who demonstrate radiographic findings of AVN should be referred to an orthopedist for consideration of operative excision and bone grafting.
Other complications after a scaphoid fracture include paresthesias in the distribution of the median nerve and wrist instability caused by disruption of the suspensory ligaments between the scaphoid and the radius and carpals. Although most median nerve symptoms resolve spontaneously, signs of serious nerve injury may persist, including intractable pain, neurotrophic changes in the skin and bones, and atrophy of hand musculature. Patients with wrist instability initially seek treatment for wrist pain that resolves within a few weeks, but later a chronic dull aching pain develops in the dorsum of the wrist, which is worsened by repeated flexion and extension of the clasped hand.
Pediatric Scaphoid Fractures
Anatomic Considerations
The scaphoid is the most commonly fractured carpal bone among pediatric patients, just as it is with adults. However, the pattern of fractures seen is significantly different because of the immature nature of the carpal bones in children. Scaphoid fractures are uncommon in children because the physis of the distal radius usually fails first. At birth, the carpal bones are entirely cartilaginous, and ossification of the scaphoid begins at approximately 4.5 years of age in girls and 5.5 years of age in boys. The scaphoid ossifies eccentrically, starting distally and proceeding proximally. This process of progressive ossification produces different fracture patterns than are seen in adults. The incidence of scaphoid fractures increases throughout childhood and peaks at the age of 15 years. Fractures of the scaphoid are rare in children younger than 8 years old.
Mechanism of Injury
Most scaphoid fractures in children are caused by falls from standing height or during sports-related activities such as biking or skateboarding. Some are caused by involvement in motor vehicle accidents or punching injuries. Because the carpal bones of children are incompletely ossified and therefore resilient, significant forces are usually required to cause a fracture. Other injuries often accompany scaphoid fractures in children, including fractures of the lunate or the distal radius or dislocation of the proximal carpal row. As is the usual pattern for young, skeletally immature patients, immature bones fail before the surrounding ligamentous attachments.
Clinical Presentation
The patient reports a fall on the extended wrist, usually from standing height. The patient also reports wrist pain and ROM limited by pain. Tenderness and some swelling in the anatomic snuffbox may be apparent during physical examination. Tenderness of the distal pole (at the anatomic snuffbox with the wrist in ulnar deviation) may also be elicited.
Imaging
If a scaphoid fracture is suspected on the basis of history, physical examination, or both, four views of the wrist are recommended: anteroposterior (AP), lateral, oblique, and pronation-ulnar deviation. Although most pediatric scaphoid fractures are nondisplaced, many are incomplete and show disruption of a single cortex. Most pediatric scaphoid fractures involve the distal third of the bone. These include both extraarticular radial avulsion fractures unique to children and intraarticular fractures of the distal pole of the scaphoid, which can be either radial or ulnar. Middle third fractures constitute approximately one third of pediatric scaphoid fractures.
Pseudo-Terry Thomas Sign
In an injured child, the gap between the ossifying scaphoid and ossifying lunate may initially appear to be wide, leading to the incorrect diagnosis of a “Terry Thomas sign” or scapholunate dissociation. The scaphoid ossifies from distal to proximal, so the distance between the ossifying scaphoid and lunate bones appears to narrow as the child ages. Comparative views of the uninjured wrist are helpful in this situation, but carpal ossification is not perfectly symmetric.
Further Imaging
Because the carpal bones are largely cartilaginous and ossify as the patient grows, scaphoid fractures are often not seen on initial radiographs. The diagnosis may be delayed 1 to 2 weeks for many patients. MRI is often needed to confirm the diagnosis. CT or bone scan are reasonable alternatives.
Indications for Orthopedic Referral
Displaced fractures, nonunions, failed nonoperative treatment, and fractures associated with carpal injuries, and fractures of the proximal pole of scaphoid should be referred to orthopedic surgeons.
Initial Treatment
Table 5-2 summarizes management guidelines for pediatric scaphoid fractures.
| initial treatment | |
| Splint type and position |
|
| Initial follow-up visit |
|
| Patient instruction |
|
| follow – up care | |
| Cast and splint type and position |
|
| Length of immobilization |
|
| Healing time |
|
| Follow-up visit interval |
|
| Repeat radiography interval |
|
| Patient instruction | Maintain finger, elbow, and shoulder ROM during immobilization |
| Indications for orthopedic consult |
|
In a child, an avulsion of the radial aspect of the distal scaphoid or a fracture of the distal third should be immobilized in a short-arm thumb spica cast or splint. The wrist should be immobilized in slight flexion and radial deviation. Patients with fractures at the waist of the scaphoid require immobilization in a long-arm thumb spica cast or splint. As with adults, pediatric patients with suspected scaphoid fractures and negative radiographs should be stabilized in thumb spica splint or cast and reevaluated in 2 weeks.
Follow-up Care
The patient should be seen again in 7 to 10 days. Repeat radiographs are necessary if the initial radiographs show no abnormalities. If the cast is loose or damaged, it should be replaced. If patients remain symptomatic at 2 weeks after the injury and no fracture has been seen on standard radiographs, advanced imaging should be obtained.
Children with an avulsion or distal-third fracture should remain in a short-arm thumb spica cast for 4 to 6 weeks. Patients with a nondisplaced scaphoid fracture should remain in long-arm thumb spica cast for 6 to 8 weeks. However, a fracture that has been left untreated for 10 days may require 10 weeks of cast immobilization: 3 to 6 weeks in a long-arm thumb spica cast followed by 3 to 7 weeks in a short-arm thumb spica cast.
Return to Sports
For athletes, the wrist should be protected in a rigid splint for sports activities until strength is 80% of the uninjured side and ROM is normal or near normal. The wrist should be protected for a minimum of 3 months after cast removal.
Complications
The most common complication among children and adolescents is failure to recognize the presence of a scaphoid fracture because of mild symptoms and radiographs that initially show no abnormalities. Nonunion is also a relatively common complication. Nonunion may be caused by neglect, misdiagnosis, or noncompliance with the treatment regimen. Most nonunions can be treated successfully with prolonged immobilization: 10 weeks are usually sufficient, but immobilization for up to 16 to 20 weeks may be necessary in some cases. Malunion can result if the unstable scaphoid fracture causes flexion of the scaphoid. Children are capable of significant remodeling in cases of a malunited scaphoid, and a trial of nonoperative therapy is warranted.
Triquetrum Fractures
Anatomic Considerations
The triquetrum is part of the proximal carpal row and articulates with the lunate, to which it is attached by ligaments. During radial deviation of the wrist the triquetrum may articulate with the capitate. The pisiform bone often overlies the triquetrum, with which it articulates anteriorly. In close proximity to the triquetrum is the triangular fibrocartilaginous complex (TFCC), a confluence of structures just distal to the ulna that includes ligaments and an articular disk. The TFCC forms a strong support on the ulnar side of the wrist.
Mechanism of Injury
Fractures of the triquetrum are the second most common fractures among the carpal bones. The fracture can be caused by either hyperflexion or hyperextension of the wrist. With hyperextension and ulnar deviation the hamate shears off the posteroradial aspect of the triquetrum. With hyperflexion, the dorsal radiotriquetral ligaments avulse their triquetral attachments. Avulsion or “chip” fractures are the most common form of fracture. Fractures of the body of the triquetrum may be caused by a direct blow or occur in association with a perilunate dislocation. Injuries to the TFCC are common after a fall on the extended wrist combined with forearm torsion.
Clinical Presentation
The patient seeks treatment after falling on the outstretched arm, usually with the wrist extended and with ulnar deviation. Intense point tenderness 2 cm distal to the ulnar styloid is highly suggestive of injury to the triquetrum. When examined, the wrist may show little swelling or discoloration. Resisted wrist extension usually reproduces the patient’s pain.
Imaging
Three views of the wrist are required: AP, true lateral, and oblique. A transverse fracture of the body of the triquetrum can usually be identified on a standard AP view. The AP view may not reveal a dorsal avulsion fracture because of the normal superimposition of the dorsal lip on the lunate. On the lateral view, a small fleck of avulsed bone may be seen dorsal to the proximal carpal row ( Fig. 5-13 ). This small avulsion is often the only radiographic sign of a triquetral fracture. If a triquetral fracture is suspected clinically and routine radiographs show no abnormalities, a computed tomography (CT) scan or magnetic resonance imaging (MRI) should be obtained.
