Metacarpal shaft fractures
- Josh Bloom, MD, MPH
Josh Bloom, MD, MPH
- Clinical Instructor, Department of Family Medicine
- University of North Carolina at Chapel Hill
Metacarpal fractures are common. They account for up to 50 percent of all hand fractures [1,2]. Fractures of the metacarpal shaft are usually the result of direct or indirect trauma, but fatigue fractures can occur in athletes or as occupational injuries due to repetitive stress. The biomechanics, diagnosis, and treatment of stress fractures are presented separately. (See "Overview of stress fractures".)
This topic will review issues related to metacarpal shaft fractures. A general overview of metacarpal fractures and discussions of other common hand and wrist injuries are presented separately. (See "Overview of metacarpal fractures" and "Scaphoid fractures" and "Proximal phalanx fractures" and "Middle phalanx fractures" and "Distal phalanx fractures" and "Distal radius fractures in adults" and "Overview of carpal fractures" and "Evaluation of the adult with acute wrist pain".)
The heads of the metacarpals are bulbous and "cam" shaped, thereby permitting adduction, abduction, flexion, extension and passive rotation of the fingers. The collateral ligaments join the metacarpal to the proximal phalanx and are taut in flexion, while having some laxity in extension (figure 1 and figure 2 and figure 3). The functional importance of this configuration is that the metacarpal phalangeal (MCP) joints should be immobilized in flexion to prevent shortening of the collateral ligaments and subsequent loss of motion.
FRACTURE PATTERNS AND MECHANISM OF INJURY
Metacarpal shaft fractures occur in three basic patterns: transverse, oblique, and comminuted.
●Transverse fractures are caused by a direct blow. These fractures are typically pulled into apex dorsal angulation by the forces of the interosseous muscles (figure 4 and figure 5 and figure 6) and extrinsic flexor tendons exerted on the metacarpal shaft.
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- CLINICAL ANATOMY
- FRACTURE PATTERNS AND MECHANISM OF INJURY
- CLINICAL PRESENTATION AND EXAMINATION
- Assessment of hand alignment and function
- - Extensor apparatus
- - Angulation
- - Rotational alignment
- DIAGNOSTIC IMAGING
- DIFFERENTIAL DIAGNOSIS
- INDICATIONS FOR SURGICAL REFERRAL
- INITIAL TREATMENT
- CLOSED REDUCTION
- Performance of fracture reduction
- FOLLOW-UP CARE
- RETURN TO SPORT OR WORK
- PEDIATRIC CONSIDERATIONS
- SUMMARY AND RECOMMENDATIONS