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Definition/ Description

The scaphoid bone is the most commonly fractured carpal bone. In young children and the elderly population scaphoid fractures are rare. The scaphoid bone is stronger than the relative weak distal radius compared in these age groups.^[1][2] A delay in diagnosis of scaphoid fractures can lead to a variety of adverse outcomes that include nonunion (no consolidation) , delayed union, decreased grip strength and range of motion, and osteoarthritis of the radiocarpal joint. Timely diagnosis, appropriate immobilization, and referral when indicated can decrease the likelihood of adverse outcomes.^[3][2]

Clinically Relevant Anatomy

The scaphoid is one of the 8 carpal bones of the wrist. It’s an important boat-shaped carpal bone that articulates with the distal radius, trapezium, and capitate. During dorsiflexion and radial deviation of the wrist, the motion is limited by the scaphoid conflict on the radius. Stress on the scaphoid, due to a forceful motion, may have a fracture as result. Scapohid fractures make up 50-80% of all carpal fractures^[2].
The major blood supply comes from the radial artery (seventy to eighty percent), twenty to thirty percent of the bone receives its blood supply from volar radial artery branches, feeding the dorsal surface. The proximal portion has no direct blood supply, what is an explanation for the cause of scaphoid necrosis on the basis of the vascular anatomy and an important complication of scaphoid fractures. ^[2][4]

Epidemiology/Etiology

Scaphoid fracture occur in people of all ages (10 – 70 years), although it is most common in young adult men following a fall, athletic injury, or motor vehicle accident^[5].Young male and persons between 10 and 19 years of age are at highest risk^[6]. Scaphoid fracture is uncommon in children because a fall results in a Salter type I or II fracture of the distal radius. Similarly, in elderly patients, the distal radial metaphysis usually fails before the scaphoid can fracture^[5].

Scaphoid injuries are more common in men than in women.^[5][6]

The scaphoid has especially joint compressive forces which result in trapezial-scaphoid shear stress, and exerts control on the scaphoid by capitolunate rotation moments. Therefore, scaphoid fractures have a high incidence of nonunion (8-10%), frequent malunion, and late sequelae of carpal instability and posttraumatic arthritis^[5].

• Because no blood vessels enter the proximal pole of the scaphoid, a higher incidence of aseptic necrosis and nonunion is noted with fractures on this side of the scaphoid ^[5].
• A scaphoid fracture can be presented in two ways: as a nondisplaced, stable fracture or as a displaced, unstable fracture.
The displaced fractures frequently are associated with ligamentous tears in the wrist. So evaluation and follow-up is recommended^[5].

Research shows that 2,4% of all wrist fractures are scaphoid fractures and there is an estimated incidence of scaphoid fractures of 29 per 100.000 persons^[6][7].

Characteristics/ Clinical Presentation

The main cause of injury is a fall on the outstretched hand with an radially deviated wrist, which results in extreme dorsiflexion at the wrist and compression to the radial side of the hand. There will be a massive force of the hand on the arm through the scaphoid bone^[1][2][8]. The patient experience a deep, dull ache in the radial part of the wrist. The pain, which often is mild, is aggravated by pinching and gripping. The wrist can be lightly swollen or bruised and, possibly, fullness in the anatomic snuffbox, suggesting a wrist effusion. Scaphoid fractures are most common in males 15 to 30 years of age^[8] and are rare in young children and infants.^[1]

Differential Diagnosis

These diagnoses can be differentiated by the location of tenderness, pain with certain maneuvers, and radiographic abnormalities.^[2][9]

Diagnosis	Physical And Radiographic Findings
Arthritis of the carpometacarpal or radiocarpal joint	Local tenderness, abnormal radiographs
De Quervain’s tenosynovitis	Lateral wrist pain, tenderness over radial styloid, positive Finkelstein’s test
Distal radius fracture	Local tenderness and deformity, abnormal plain radiographs
Extensor carpi radialis strain (longus and brevis)	Local tenderness, swelling, and pain elicited with wrist flexion
First metacarpal fracture	Local tenderness and deformity, abnormal plain radiographs
Flexor carpi radialis strain	Local tenderness, swelling, and pain elicited with wrist extension
Injuries to radioulnar joint	Local tenderness
Scapholunate dissociation	Tenderness over scapholunate ligament, increased gap between scaphoid and lunate on plain films
Scaphoid fracture	Anatomic snuffbox tenderness, pain with scaphoid compression test, tenderness of scaphoid tubercle

Diagnostic Procedures

Bone scintigraphy has been advocated by many as the ideal investigation for occult scaphoid fractures. It has been shown to have 100% sensivity and 98% specificiteit for scaphoid fractures compared with only 64% for plain radiography. The clinical signs of a scaphoid fracture were swelling and tenderness in the anatomical snuff box. Research has shown that the use of MRI is effective to determinate a scaphoid fracture. Both methods found all fractures, but the MRI found some significant ligamentous and carpal instabilities. The bone scintigraphy was a cost-effective and accurate method for assessing occult scaphoid fractures compared with repeat plain radiography.^[10][11]

Outcome Measures

• PRWE, a fifteen-item questionnaire was designed to measure wrist pain and disability. The reliability was excellent (ICCs > 0.90). Validity assessment demonstrated that the instrument detected significant differences over time (p [8]
• PEM, the Patient Evaluation Measure has a simple layout with questions asked in a visual analogue form. Patients are asked to read and comprehend the question alone and not the description of each interval answer.^[5]

Examination

When examining a patient with a suspected scaphoid injury, it is important to compare the injured wrist with the uninjured wrist. The classic hallmark of anatomic snuffbox tenderness on examination is a highly sensitive (90 percent) indication of scaphoid fracture, but it is nonspecific (specificity, 40 percent)^[1] For example, a false-positive result can occur when the radial nerve sensory branch, which passes through the snuffbox, is pressed and causes pain. Other physical examination maneuvers should be performed. Tenderness of the scaphoid tubercle (i.e., the physician extends the patient’s wrist with one hand and applies pressure to the tuberosity at the proximal wrist crease with the opposite hand) provides better diagnostic information; this maneuver has a similar sensitivity (87 percent) to that of anatomic snuffbox tenderness, but it is significantly more specific (57 percent)^[1] Absence of tenderness with these two maneuvers makes a scaphoid fracture highly unlikely.

Pain with the scaphoid compression test (i.e., axially/longitudinally compressing a patient’s thumb along the line of the first metacarpal) also was shown, in a retrospective analysis^[3], to be helpful in identifying a scaphoid fracture, but in another study^[2], this technique had a poor predictive value for identifying scaphoid fractures. Another maneuver that suggests fracture of the scaphoid is pain in the snuffbox with pronation of the wrist followed by ulnar deviation (52 percent positive predictive value, 100 percent negative predictive value)^[2][2]

Medical Management

Cast immobilization is the standard treatment for treating a scaphoid fracture. With cast immobilization, chance of non-union is approximately 20%. Therefore, with displaced or unstable fractures, operative treatment is recommended.^[8] Though this improves the rate of non-union, the complication rate for ORIF is 30%.^[5]

Nonunion of a scaphoid fracture, however, can result in carpal malalignment and progressive radiocarpal arthrosis. The real effect of malunion, however, is less clearly defined. In a series of 160 scaphoid nonunions treated with internal fixation and bone grafting, of which 90% healed, failure to achieve union was related to a proximal fracture location, avascularity of the proximal pole, instability of the fracture, and delay to surgery. Importantly, residual flexion deformity of the scaphoid did not have an effect on the outcome. Therefore, malunion was not thought to be a contributing factor to a poor result. This study, however, demonstrated that the length of immobilization negatively affects the functional outcome.^[5]

The nondisplaced stable nonunion without degenerative changes may be treated with bone grafting with or without hardware. Nonvascularized autogenous bone graft from the distal radius or iliac crest may be sufficient, although vascularized bone grafting should be considered in the presence of an avascular proximal pole as determined by MRI or intraoperative findings. In addition, there is the caveat that if the initial bone grafting fails future surgery is less likely to be successful. The fracture site should be freed from fibrous nonunion or interposed tissue, and hardware may or may not be placed. Hardware placement provides additional stability but requires bony removal for placement. Kirshner wires may be used, but screw fixation may provide the advantage of compression of fracture fragments.
In short, if degenerative arthritis is absent, and the carpus can be salvaged, one may consider bone grafting, either standard or vascularized, with or without internal fixation. However, if substantial degenerative arthritis is present, limited or complete wrist arthrodesis may yield a stable, painless result. Alternatively, proximal row carpectomy or anterior interosseous nerve (AIN) and posterior interosseous nerve (PIN) denervation neurectomy may be considered. Prior to surgery a trial of cast immobilization to simulate the fused wrist, or an AIN or PIN block may be helpful to clarify the possible effect of the desired procedure on the patient’s symptoms.^[6]

Fractures are usually classified by Herbert and Fisher’s system:
Internal fixation was considered desirable in all cases where control of instability would not only ensure a satisfactory outcome, but would also allow for early functional recovery of the wrist. Thus, in the treatment of acute fractures, it became essential to differentiate between those with a good prognosis, which would unite within six to eight weeks, and those that would not. A retrospective study of over 200 scaphoid fractures indicated that undisplaced or stable fractures had a good prognosis with conservative treatment if treated early. However, those fractures presenting late, as well as those showing instability at the fracture site (of which five common patterns were recognisable), had a much poorer prognosis^[7]. Similarly, fractures showing signs of delayed union after six to eight weeks in plaster, as well as those with clear signs of non- union, did not appear to do well with conservative treatment. Thus, all scaphoid fractures presenting for treatment during the period of this trial were classified according to their radiographic appearance. In order to recognise these different fracture types, it is essential that adequate radiographs are taken of both wrists. These should include postero-anterior views in full ulnar and radial deviation, as well as 45-degree obliques and true laterals with the wrist in neutral flexion.^[7]

• Type A (acute stable) fractures were treated conservatively and have not been included in this series. Acute but stable fractures such as fractures of the tubercle, incomplete or undisplaced fractures of the waist
• Type B (acute unstable) fractures were treated by primary internal fixation as soon as practicable after the injury. Acute unstable fractures such as distal oblique fractures, complete waist fractures, proximal pole fractures, and fracture dislocation
• Type C fractures (which showed signs of delayed union after six or more weeks in plaster) were treated operatively. The plaster was removed at least two weeks before operation to mobilise the wrist and recalcify the bone. Similarly, “late” fractures presenting some weeks after injury were included in this group and were treated by primary screw fixation. Fractures with evidence of delayed union.
• Type D fractures (with established non-union) must be differentiated from acute fractures, even when there is no definite history of previous injury. In this group screw fixation combined with bone grafting is indicated if the patient has significant symptoms or is at risk of developing secondary degenerative changes in the radiocarpal joint.^[7]

Physical Therapy Management

As a basic rule, in a patient with a clinically suspected scaphoid fracture but negative initial radiographs, it is reasonable to apply a short arm thumb spica and reevaluate the patient in two weeks. If a cast is not applied, the fracture can worsen over the following months. MRI or bone scintigraphy may be used initially if the patient desires an alternative approach. At the two-week visit, the patient should be free of pain, and a follow-up radiograph should be obtained.^[2]

The fractured scaphoid exhibits certain behavior that inhibits healing. Fracture fragments are inherently unstable and prone to displacement, and require motionless contact to achieve union.^[5] As mentioned before, the blood supply of the scaphoid is tenuous. For therapeutic decision making, the scaphoid is divided into three anatomic sections: proximal, medial, and distal. Fractures are further subdivided into displaced and non-displaced types.^[2]

Nondisplaced Fractures
Nondisplaced distal fractures heal well with strict immobilization in a well-molded short arm thumb spica. Controversy exists over whether to use a long arm or a short arm cast. One comparison, ^[9]found that nondisplaced fractures healed well regardless of the type of cast that was used. Current treatment for this type of fracture is a thumb spica, but some evidence suggests that the thumb could be omitted from the cast. A randomized prospective trial^[10], found that immobilization of the thumb did not improve outcomes for nondisplaced fractures. Screw fixation may speed recovery to pre-injury activities; referral for surgery may be indicated, depending on the needs of the patient^[11]. As the fracture line moves proximally, there is more risk of displacement and nonunion; therefore, it would be appropriate to refer these patients for orthopedic consultation. If conservative treatment is attempted, a long arm cast with thumb immobilization is appropriate.^[2][12]

Displaced Fractures
Fractures with even small amounts of displacement are prone to nonunion, and operative treatment is recommended^[1].  For the fixation, double-threaded headless screws are preferred. Wich operative technique to use depends on the fracture morphology.^[13] Splinting and referral are indicated.^[2]

Traditionally, undisplaced and stable scaphoid fractures are treated by casting in short- or long-arm casts. After the immobilization you must start with stretching exercises en strengthening exercises.^[3][2]

Stretching exercises:

• Flexion: bend your wrist forward
• Extension: bend your wrist backward
• Radial and ulnar deviation: move your wrist side to side
• Wrist stretch: press the back of the hand on your injured side with your other hand to help bend your wrist.
• Wrist extension stretch: Stand at a table with your palms down, fingers flat, and elbows straight. Lean your body weight forward.

Strengthening exercises:

• Wrist flexion and extension: Hold a weight in your hand and bend your wrist upward and downward.
• Finger flexion an extension: exercises with a powerweb™
• Forearm pronation and supination: keep your arm in an angle of 90°, Turn your palm up and hold for 5 seconds. Then slowly turn your palm down and hold for 5 seconds.^[2]

Revalidation week to week

Rehabilitation considerations immediately following injury to 1 week^[5]

For casted fractures

• Active range of motion (AROM) and passive range of motion (PROM) to the digits, except the thumb, which is immobilized
• AROM and active-assisted range of motion (AAROM) exercises to the shoulder
• Isometric exercises to the biceps, triceps, and deltoid muscles

Following open reduction internal fixation (ORIF) surgery

• Elevation of the arm to treat dependent edema
• AROM and PROM of digits, except the thumb
• AROM and AAROM exercises to the elbow and shoulder
• Isometric exercises to the biceps, triceps, and deltoid muscles
• Limitation of supination and pronation

Rehabilitation considerations in 2 weeks^[5]

The clinician may obtain bone or CT scans in the event of continued pain and tenderness over the snuffbox with negative radiographic findings.
Bone stimulators have been increasingly used for stable, non-displaced fractures and for suspected scaphoid fractures with negative radiographic findings, although both uses are still somewhat controversial.
A short-arm cast is indicated for a suspected fracture, while a long-arm cast is used for a known fracture.
The patient should continue ROM exercises for casted fractures and ORIF, as above.

Rehabilitation considerations in 4-6 weeks^[5]

For casted fractures

• Continue exercises as above.
• Limit supination and pronation.
• Change the long-arm cast to a short-arm cast (bridging callus indicates stability).

Following ORIF surgery

• Advance therapy with gentle AROM of the wrist and gentle opposition and flexion/extension exercises to the thumb.
• Continue elbow and shoulder exercises.
• Remove the short-arm cast at 6 weeks if the fracture appears to be radiographically healed.
• Use a wrist splint for protection.

Rehabilitation considerations in 8-12 weeks^[5]

For casted fractures

• Remove the short-arm cast at 10-12 weeks if the fracture appears to be radiographically and clinically healed.
• A wrist splint may be used for protection

For casted fractures and following ORIF

• Consider pulsed electrical stimulation if no evidence of union is noted by 8 weeks, and consider surgery with bone grafting if progress is not observed by 12-14 weeks
• Advance therapy with gentle AROM of the wrist and with thumb exercises
• Begin grip strengthening with the use of silicone putty at 10 weeks
• Advance as tolerated to progressive resistive exercises (PREs)

Key Research

• Scaphoid
• Scaphoid fracture
• Scaphoid fracture therapy
• Differential diagnosis scaphoid fracture
• Medical management scaphoid fracture

Resources

Clinical Bottom Line

The scaphoid bone is the most commonly fractured carpal bone. Stress on the scaphoid, due to a forceful motion, may have a fracture as result (mostly due to a fall on outstretched arm). The pain, which often is mild, is aggravated by pinching and gripping. The diagnoses can be differentiated by the location of tenderness, pain with certain maneuvers, and radiographic abnormalities. The length of immobilization affects negatively the outcomes. Internal fixation provided a satisfactory outcome for control of instability and a early functional recovery of the wrist. There are different fractures types classified by Herbert and Fisher’s system. To recognize these different fracture types, it is essential that adequate radiographs are taken of both wrists.

References

1. ↑ ^{1.01.11.21.31.41.5} Gutierrez G, Office management of scaphoid fractures. Phys Sports Med. 1996;24:60–70. Level of evidence: 5
2. ↑ ^{2.002.012.022.032.042.052.062.072.082.092.102.112.122.132.14} T. Grant Phillips et al, Diagnosis and Management of Scaphoid Fractures, Am Fam Physician. 2004 Sep 1;70(5):879-884. Level of evidence: 5
3. ↑ ^3.03.13.2 Greene WB, Essentials of musculoskeletal care. 2d ed. Rosemont, Ill.: American Academy of Orthopaedic Surgeons, 2001:252–4. Level of evidence: 5
4. ↑ Gelberman RH, Menon J., The vascularity of the scaphoid bone, The Journal of Hand Surgery Am. 1980 Sep;5(5):508-13. Level of evicence:5
5. ↑ ^{5.005.015.025.035.045.055.065.075.085.095.105.115.125.13} Scott R. Laker et all, Scaphoid injury (Epidemiology), Medspace. 2015, 6 April. Level of evicence:5
6. ↑ ^6.06.16.26.3 Van Tassel DC. Et all, Incidence estimates and demographics of scaphoid fracture in the U. S. Population, The Journal of hand surgery. 2010, august. Level of evidence: 2B
7. ↑ ^7.07.17.27.3 Duckworth, Andrew D. et all, Scaphoid fracture epidemiology, Journal of Trauma and Acute Care Surgery. 2012, February – Volume 72 – Issue 2 – p E41–E45. Level of evidence: 5
8. ↑ ^8.08.18.28.3 Mc Dermid, Patient Rating of Wrist Pain and Disability: A Reliable and Valid Measurement Tool, 1998. Levels of evidence: 2A
9. ↑ ^9.09.1 Bill Schloss Gillian Lieberman, MD, Scaphoid fractures, Harvard Medical School, Year Harvard Medical School, Year-IV. Januari 2001: pg 3. Level of evicence: 5
10. ↑ ^10.010.1 A comparison of bone scintigraphy and MRI in the early diagnosis of the occult scaphoid waist fracture, skeletal radiology, 1998, level of evidence: 3B
11. ↑ ^11.011.1 Moran C. G., Combining the Clinical Signs Improves Diagnosis of Scaphoid Fractures A prospective study with follow-up, 2004, level of evidence: 3B
12. ↑ Grewal, Ruby, Nina Suh, and Joy C. MacDermid. “Is casting for non-displaced simple scaphoid waist fracture effective? A CT based assessment of union.” The open orthopaedics journal 10 (2016): 431. (level of evidence 2B)
13. ↑ Schädel-Höpfner, M., et al. “Acute scaphoid fractures: Management under consideration of the new S3-level guideline.” Der Orthopade 45.11 (2016): 945-950. (level of evidence 5)