Basics
Description
- Most metacarpal injuries are caused by crush injuries, a direct blow with hand vs. object, or burns.
- Most common fracture is boxers fracture of distal 5th metacarpal neck.
Diagnosis
Signs and Symptoms
- Pain or swelling at the site of injury
- Deformity at the site of injury
- Malalignment of the distal tip of the finger on flexion indicates rotational deformity.
- Lines drawn down the longitudinal axis of each digit in flexion normally should converge on the scaphoid volarly.
- Limitation of movement secondary to pain and anatomic deformity
Have a high suspicion for "fight bite. " This injury is the direct blow of a closed fist against a human tooth:
- Concern is violation of the extensor sheath, metacarpophalangeal (MCP) joint, or metacarpal head by a tooth, with subsequent infection by oral flora.
History
Not all patients are truthful as to cause of injury.
Essential Workup
Exam should pay specific attention to skin integrity and alignment of the distal phalanges in flexion and extension.
Diagnosis Tests & Interpretation
Imaging
- Hand radiographs when fracture suspected, and/or to rule out opaque foreign body
- Special radiographic views (CT) of the proximal metacarpals and the carpometacarpal joints may be necessary for patients with a suggestive physical exam and no definite fracture on a standard 3-view series.
Differential Diagnosis
Fracture of the metacarpal may be accompanied by dislocation of adjacent phalanges or carpal bones.
Treatment
Pre-Hospital
- Most do not require EMS transport solely for metacarpal injury.
- Cautions:
- Metacarpal injuries should be splinted in position of comfort.
Initial Stabilization/Therapy
- Other, more serious injuries should be treated 1st.
- Immobilize hand pending evaluation.
- Lacerations should be cleaned as soon as possible, and consideration should be given to the possibility of foreign body.
- Thermal burns are treated with early analgesia.
Ed Treatment/Procedures
- Elevation, rest, and intermittent application of ice for the 1st 24 hr are appropriate treatment for all hand injuries (RICE).
- Boxers fractures usually have some volar flexion of the distal fragment:
- Reduction should be attempted for volar angulation of 40 ° or more.
- Fractures of the 4th and 5th metacarpals that are stable and with no significant rotational component can be treated with a padded ulnar gutter splint.
- Fractures of the index and middle finger metacarpals are more difficult to stabilize:
- Radial gutter splint and early orthopedic referral
- Thumb metacarpal fractures are uniformly complicated and all should be referred early to a hand surgeon or orthopedist:
- Place in thumb spica splint.
- Dislocations should be reduced immediately and splinted; metacarpal dislocations are rare and frequently need open reduction and pinning.
- Appropriate splinting position for the MCP joint is the intrinsic plus, or "cobra " position (20 " 30 ° wrist extension):
- MCP joint as close to 90 ° of flexion as possible
- Proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints in extension
- Antibiotics for oral flora should be started early for any open injury to the metacarpals suspicious for injury against a tooth, and may require curettage of the impaction site in the operating room.
- Simple torus (buckle) fractures may be splinted and may be followed by a primary care physician.
Medication
- Check for tetanus status and vaccinate per immunization schedule.
- Silvadene cream or bacitracin ointment is appropriate for thermal burn injury.
- Analgesics may be necessary; NSAIDs or hydrocodone is usually sufficient.
- For human bites or dirty wounds, administer amoxicillin/clavulanate (Augmentin), or:
- A cephalosporin or other penicillinase-resistant antibiotic given parenterally is appropriate.
Follow-Up
Disposition
Admission Criteria
- Open fractures or dislocations require urgent surgical intervention and should be admitted.
- All thumb metacarpal fractures or dislocations should be seen by an orthopedist or hand surgeon because of the special importance of the thumb in all activities of the hand.
- Infection from a bite wound requires prompt orthopedic consultation, admission for irrigation, debridement, and IV antibiotics.
Discharge Criteria
- Patients with a stable transverse or oblique fracture in a good splint may be discharged for early orthopedic follow-up.
- Metacarpal " carpal dislocations are usually unstable enough to require surgery even if reduction is achieved, but this may be semiurgent rather than emergent.
- If a metacarpal fracture produces impaired range of motion or misalignment of the finger, the patient will require surgical repair in the 1st several days after injury.
Epiphyseal injuries mandate orthopedic referral.
Pearls and Pitfalls
With all metacarpal injuries assure proper rotational alignment.
Additional Reading
- American College of Radiology, Expert Panel on Musculoskeletal Imaging. Acute Hand and Wrist Trauma. 2001.
- Chudnofsky CR, Byers SE. Clinical Procedures in Emergency Medicine: Splinting Techniques. 5th ed. Philadelphia, PA: Saunders Elsevier; 2010.
- Harrison B, Holland P. Diagnosis and management of hand injuries in the ED. Emerg Med Pract. 2005;7(2):1 " 28.
Codes
ICD9
- 815.00 Closed fracture of metacarpal bone(s), site unspecified
- 815.04 Closed fracture of neck of metacarpal bone(s)
- 927.20 Crushing injury of hand(s)
- 815.10 Open fracture of metacarpal bone(s), site unspecified
- 815.01 Closed fracture of base of thumb [first] metacarpal
- 815.02 Closed fracture of base of other metacarpal bone(s)
- 815.03 Closed fracture of shaft of metacarpal bone(s)
- 815.09 Closed fracture of multiple sites of metacarpus
- 815.0 Closed fracture of metacarpal bones
- 815.11 Open fracture of base of thumb [first] metacarpal
- 815.12 Open fracture of base of other metacarpal bone(s)
- 815.13 Open fracture of shaft of metacarpal bone(s)
- 815.14 Open fracture of neck of metacarpal bone(s)
- 815.19 Open fracture of multiple sites of metacarpus
- 815.1 Open fracture of metacarpal bones
- 815 Fracture of metacarpal bone(s)
- 834.01 Closed dislocation of metacarpophalangeal (joint)
ICD10
- S62.309A Unsp fracture of unsp metacarpal bone, init for clos fx
- S62.368A Nondisp fx of neck of oth metacarpal bone, init for clos fx
- S67.20XA Crushing injury of unspecified hand, initial encounter
- S62.309B Unsp fracture of unsp metacarpal bone, init for opn fx
- S62.319A Disp fx of base of unsp metacarpal bone, init for clos fx
- S62.329A Disp fx of shaft of unsp metacarpal bone, init for clos fx
- S63.269A Dislocation of metacarpophalangeal joint of unspecified finger, initial encounter
SNOMED
- 427914009 Injury of metacarpal bone (disorder)
- 208393000 fracture of metacarpal bone (disorder)
- 263210007 fracture of neck of fifth metacarpal (disorder)
- 1370007 Open fracture of metacarpal bone (disorder)
- 208397004 Closed fracture finger metacarpal base (disorder)
- 263209002 Fracture of base of fifth metacarpal (disorder)
- 312844001 Dislocation of metacarpophalangeal joint (disorder)
- 55716004 Fracture of base of metacarpal bone other than first metacarpal (disorder)
- 78292000 Fracture of shaft of metacarpal bone (disorder)