Metacarpal Fracture and Dislocation
For as much as we use our hands, it is surprising that they are not injured more frequently. Sports-related metacarpal fractures most commonly occur during participation in contact sports, such as football, rugby, or basketball, in which the hands are unprotected. A direct fall onto the hand (FOOSH injury) while cycling, running, or skiing may also result in a fracture.
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Related Medscape Reference topics:
Hand, Fracture and Dislocations: Metacarpal [in the Plastic Surgery section]
Metacarpal Fractures [in the Orthopedic Surgery section]
Related Medscape topics:
Resource Center Adolescent Medicine
Resource Center Exercise and Sports Medicine
Specialty Site Orthopaedics
Until the early 20th century, metacarpal fractures were treated exclusively by nonoperative means. Surgery was first suggested as an alternative treatment for certain fracture patterns in the 1920s. [1, 2]
Metacarpal and phalangeal fractures are the most common fractures of the upper extremity. They account for approximately 10% of all orthopedic fractures. [2, 3] Most occur in young adults, usually as a result of direct blunt trauma, axial loading, or throwing a punch during an altercation. The thumb and small finger are the most frequently injured.
The finger metacarpals describe a gentle arch in both the axial and coronal planes. Each bone is relatively straight along its dorsal cortex and concave along the palmar surface.
The carpometacarpal (CMC) joints consist of 5 metacarpal bases that articulate with the trapezoid, trapezium, capitate, and hamate. Articular congruity of the joint surfaces, in combination with the strong interosseous and extrinsic palmar and dorsal ligaments, provides stability to the CMC joint. The CMC joints of the index and long fingers are essentially fixed, whereas those of the ring and small fingers enjoy 20-30° of motion in flexion-extension. The thumb is extremely mobile at the CMC joint.
The opposing saddle shapes of the metacarpal base and the articulating trapezium allow for flexion, extension, abduction, and adduction. The joint capsule and ligaments permit a small degree of rotation. The most important soft-tissue support for the first CMC joint is the anterior oblique ligament, which runs from the tubercle of the trapezium to the volar beak of the metacarpal. This ligament may be ruptured in a dislocation, but it is most commonly avulsed by a fragment of bone from the ulnar corner of the metacarpal (Bennett fracture). 
The anatomic relationships described above maintain proper rotational alignment of the fingers and allow for the smooth production of power grip and the ability to clench the fist, functions that are required in many sports. The high mobility of the thumb enables both pinching (squeezing small equipment or objects between the thumb and the forefinger) and grasping of large objects.
Bennett fractures are unstable because of the deforming forces of the intrinsic and extrinsic muscles. The anterior oblique ligament stabilizes the volar-ulnar fragment, but the thenar muscles and abductor pollicis longus displace the remaining metacarpal in the proximal, dorsal, and radial directions. 
An analogous situation exists with the reverse Bennett fracture of the small-finger metacarpal. Intermetacarpal ligaments stabilize the radial fragment. The hypothenar and the flexor and extensor carpi ulnaris muscles pull the remaining metacarpal proximally and dorsally.
Lambotte A. The Classic. Contribution to conservative surgery of the injured hand. By Dr. A. Lambotte. 1928. Clin Orthop Relat Res. 1987 Jan. 214:4-6. [Medline].
Stern PJ. Fractures of the metacarpals and phalanges. Green DP, Hotchkiss RN, Pederson WC, eds. Green’s Operative Hand Surgery. 4th ed. New York, NY: Churchill Livingstone; 1999. 711-71.
Gaheer RS, Ferdinand RD. Fracture dislocation of carpometacarpal joints: a missed injury. Orthopedics. 2011 May 18. 34(5):399. [Medline].
Brownlie C, Anderson D. Bennett fracture dislocation – review and management. Aust Fam Physician. 2011 Jun. 40(6):394-6. [Medline].
Yoshida R, Shah MA, Patterson RM, Buford WL Jr, Knighten J, Viegas SF. Anatomy and pathomechanics of ring and small finger carpometacarpal joint injuries. J Hand Surg [Am]. 2003 Nov. 28(6):1035-43. [Medline].
Lane CS. Detecting occult fractures of the metacarpal head: the Brewerton view. J Hand Surg [Am]. 1977 Mar. 2(2):131-3. [Medline].
Gedda KO, Moberg E. Open reduction and osteosynthesis of the so-called Bennett’s fracture in the carpo-metacarpal joint of the thumb. Acta Orthop Scand. 1953. 22(3):249-57. [Medline].
Livesley PJ. The conservative management of Bennett’s fracture-dislocation: a 26-year follow-up. J Hand Surg [Br]. 1990 Aug. 15(3):291-4. [Medline].
Chong AK, Chew WY. An isolated ring finger metacarpal shaft fracture?–beware an associated little finger carpometacarpal joint dislocation. J Hand Surg [Br]. 2004 Dec. 29(6):629-31. [Medline].
Pomares G, Strugarek-Lecoanet C, Dap F, Dautel G. Bennett fracture: Arthroscopically assisted percutaneous screw fixation versus open surgery: Functional and radiological outcomes. Orthop Traumatol Surg Res. 2016 May. 102 (3):357-61. [Medline].
Moon SJ, Yang JW, Roh SY, Lee DC, Kim JS. Comparison between Intramedullary Nailing and Percutaneous K-Wire Fixation for Fractures in the Distal Third of the Metacarpal Bone. Arch Plast Surg. 2014 Nov. 41(6):768-72. [Medline]. [Full Text].
Burton RI, Eaton RG. Common hand injuries in the athlete. Orthop Clin North Am. 1973 Jul. 4(3):809-38. [Medline].
Burkhalter WE. Closed treatment of hand fractures. J Hand Surg [Am]. 1989 Mar. 14(2 pt 2):390-3. [Medline].
Jahss SA. Fractures of the metacarpals: a new method of reduction and immobilization. J Bone Joint Surg Am. 1938. 20:178-86. [Full Text].
David R Steinberg, MD Director of Hand Fellowship, Associate Professor, Department of Orthopedic Surgery, University of Pennsylvania Health System
Disclosure: Nothing received, but have long-term ownership of public equities from Johnson & Johnson. for: Johnson & Johnson.
Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference
Disclosure: Received salary from Medscape for employment. for: Medscape.
Craig C Young, MD Professor, Departments of Orthopedic Surgery and Community and Family Medicine, Medical Director of Sports Medicine, Medical College of Wisconsin
Craig C Young, MD is a member of the following medical societies: American Academy of Family Physicians, American College of Sports Medicine, American Medical Society for Sports Medicine, Phi Beta Kappa
Disclosure: Nothing to disclose.
Gerard A Malanga, MD Founder and Partner, New Jersey Sports Medicine, LLC and New Jersey Regenerative Institute; Director of Research, Atlantic Health; Clinical Professor, Department of Physical Medicine and Rehabilitation, University of Medicine and Dentistry of New Jersey-New Jersey Medical School; Fellow, American College of Sports Medicine
Gerard A Malanga, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Physical Medicine and Rehabilitation, American College of Sports Medicine, American Institute of Ultrasound in Medicine, International Spine Intervention Society, North American Spine Society
Disclosure: Serve(d) as a speaker or a member of a speakers bureau for: Lipogems.
Metacarpal Fracture and Dislocation
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