- Kevin deWeber, MD, FAAFP, FACSM
Kevin deWeber, MD, FAAFP, FACSM
- Family Medicine of SW Washington Residency
- PeaceHealth SW Medical Center
- Affiliate Associate Professor of Family Medicine
- Oregon Health and Science University
- Clinical Instructor of Family Medicine
- University of Washington School of Medicine
Upper extremity fractures are among the most common of the extremity injuries with carpal fractures accounting for 18 percent of hand fractures and 6 percent of all fractures . Of these, fractures to bones of the distal row are less frequent than fractures of the bones of the proximal row (ie, scaphoid, lunate, triquetrum, and pisiform). Isolated capitate fracture accounts for approximately one to two percent of carpal fractures , but may be more common than previously thought given that some fractures do not appear on plain radiographs and may heal without immobilization .
This topic reviews fractures of the capitate in adults. An overview of carpal fractures and discussions of other wrist injuries in adults are presented separately. (See "Overview of carpal fractures" and "Scaphoid fractures" and "Distal radius fractures in adults".)
The capitate is the largest carpal bone. Distally, it articulates primarily with the base of the third metacarpal and a small portion of the fourth; radially with the trapezoid; proximally with the scaphoid and lunate; and on its ulnar side with the hamate (image 1 and figure 1 and figure 2 and figure 3). The capitate resembles the scaphoid in that its blood supply at the proximal pole is provided by vessels coursing distal to proximal, increasing the risk of fracture complications from interruption of the blood supply. The anatomy of the wrist is reviewed in detail separately. (See "Anatomy and basic biomechanics of the wrist".)
HISTORY AND MECHANISM OF INJURY
A number of mechanisms can cause capitate injuries. Cadaver studies suggest that an injury sustained with the wrist in marked extension and radial deviation can cause the dorsal lip of the distal radius to contact the scaphoid, causing a fracture at its waist, and then the force is transmitted to the capitate, which fractures at its neck [2,4]. Excessive palmar flexion is another reported cause . Isolated fractures can occur from a dorsal blow or crush injury. Of note, injuries sustained from excessive palmar or dorsiflexion under a load (eg, falling onto an outstretched hand) may involve dislocations or fracture dislocations, and involve other carpal bones (eg, scaphoid). (See "Scaphoid fractures".)
Capitate fractures rarely occur in isolation; concomitant carpal fractures are common. A well-documented example is “scaphocapitate syndrome.” This injury involves a force exerted on the radial styloid that causes fractures of both the scaphoid waist and proximal capitate. Depending upon the force, this injury can extend to perilunate dislocation . (See "Evaluation of the adult with acute wrist pain", section on 'Perilunate and lunate dislocations'.)
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- PERTINENT ANATOMY
- HISTORY AND MECHANISM OF INJURY
- SYMPTOMS AND EXAMINATION FINDINGS
- RADIOGRAPHIC FINDINGS
- DIFFERENTIAL DIAGNOSIS
- INDICATIONS FOR SURGICAL REFERRAL
- INITIAL TREATMENT
- FOLLOW-UP CARE
- RECOMMENDATIONS FOR RETURN TO SPORT OR WORK
- SUMMARY AND RECOMMENDATIONS