The Common Vein Copyright 2011
Definition
Fractures of the metacarpals are usually caused by direct trauma, twisting, avulsion, and stress trauma resulting in a transverse, obliqe, or spiral fracture in the head, neck, shaft, or base of the metacarpals.
Head fractures include epiphyseal fractures, collateral ligament avulsions, oblique, vertical, horizontal, comminuted, Boxer’s fractures with join extension, and fractures associated with bone loss.
Neck fractures occur from direct trauma with volar comminution and dorsal apex angulation.
Shaft fractures are described by the angulation, rotation, and displacement.
Metacarpal base fractures can occur in the fingers or thumb. The base of the second, third, and fourth fingers are generally minimally displaced. A fracture through the base of the thumb can be intraarticular or extraarticular. The partial articular fracture is known as a Bennett fracture, and the complete articular fracture is known as a Rolando fracture.
The fracture may be complicated in the acute phase by neurovascular injury, or in the subacute or chronic phases by nonunion, malunion, infection, osteonecrosis, or osteoarthritis.
The diagnosis of this injury is usually made by a combination of physical examination and x-ray imaging.
Imaging includes the use of plain x-rays, and if indicated CT-scan, or MRI.
It in the subacute and chronic phases it may be complicated by nonunion, malunion, soft tissue injury, infection osteonecrosis, and vascular injury. Osteoarthritis is a late complication
Diagnosis is by physical exam and x-ray imaging.
Imaging includes the use of x-rays, CT-scans, and occasionally MRI.
Treatment depends on the specific type of fracture and how acutely sick the patient is.
Metacarpal head fractures require an anatomic reduction and splinting in a protected position. Percutaneous pinning can be done to help hold a reduction. Plates and screws can be used if there is comminution.
Metacarpal neck fractures are closed reduced initially. Acceptable deformity is 10 degrees of angulation for the 2nd and 3rd metacarpal and 30 to 40 degrees for the 4th and 5th metacarpals. Operative fixation is required for unstable fractures by percutanous pins or plate fixation.
Metacarpal shaft fractures are reduced and splinted if nondisplaced or minimally displaced. Operative indications are for rotational deformity or dorsal angulation of 10 degrees for the 2nd and 3rd metacarpals or 40 degrees for the 4th and 5th metacarpals. Surgery can consist of percutaneous pinning or plate fixation.
Metacarpal base fractures that are intraarticular can be treated with closed reduction and percutaneous pinning or ORIF. Extraarticular fractures can be closed reduced and casted, but some unstable fractures require percutaneous pinning.
References
Davis MF, Davis PF, Ross DS. Expert Guide to Sports Medicine. ACP Series, 2005.
Elstrom J, Virkus W, Pankovich (eds), Handbook of Fractures (3rd edition), McGraw Hill, New York, NY, 2006.
Koval K, Zuckerman J (eds), Handbook of Fractures (3rd edition), Lippincott Williams & Wilkins, Philadelphia, PA, 2006.
Lieberman J (ed), AAOS Comprehensive Orthopaedic Review, American Academy of Orthopaedic Surgeons, 2008.
Moore K, Dalley A (eds), Clinically Oriented Anatomy (5th edition), Lippincott Williams & Wilkins, Philadelphia, PA, 2006.