Fracture, Metacarpal Neck: I-V

Ovid: 5-Minute Sports Medicine Consult, The

Fracture, Metacarpal Neck: I-V
Quynh Hoang
Chris Koutures
  • The metacarpal neck (distal metaphysis) is the aspect of the metacarpal shaft immediately underneath the metacarpal head.
  • The weakest point of the metacarpal is located at the distal metaphysis, so metacarpal fractures frequently involve the neck (1)[C].
  • The mechanism of injury is usually an axial load on the metacarpal phalangeal (MCP) joint while in a flexed position, such as when throwing a punch.
  • Fractures about the metacarpal neck must be scrutinized for malrotation and angulation.
  • As 2nd and 3rd metacarpals are necessary for handgrip power, much less angulation is tolerated in these injuries.
  • Synonym(s): Boxer's fracture; 5th metacarpal neck fracture
  • 5th metacarpal neck fractures (boxer's fractures) are the most common hand fracture, accounting for 20% of all hand fractures (1)[C],(2)[B].
  • Fractures of the 1st metacarpal neck are uncommon.
Risk Factors
Out-of-control tempers: Boxer's fractures usually are due to striking an opponent or a wall with a clenched fist.
  • Due to the action of the interosseus muscles, the distal fracture fragment (metacarpal head) displaces volarly, resulting in an apex dorsal angulation.
  • The index and long fingers cannot tolerate angulation deformities given their relatively fixed articulations with the distal carpal bones.
  • The ring and small fingers, however, have limited flexion and extension, so angular deformities are better tolerated and they heal with minimal loss of function.
  • Axial load or direct trauma, often to clenched fist or dorsum of the hand
  • Immediate pain and swelling noted
Physical Exam
  • Swelling and tenderness on the dorsum of the hand, often accompanied by metacarpophalangeal (MCP) joint depression
  • Extreme angulation may lead to pseudoclawing, ie, hyperextension of the MCP joint along with proximal interphalangeal (PIP) joint flexion as the patient attempts to extend the finger.
  • Tenderness and swelling about the dorsal aspect of the distal metacarpals. Examine skin closely for teeth marks or other injuries.
  • Evaluate the digits for malrotation, which occurs more in 4th and 5th metacarpal neck fractures. Have the patient bring all the fingernails into the palm and compare with the noninjured hand. All the nails should point toward the base of the 1st metacarpal. If the injured finger is out of this alignment, strongly suspect significant fracture malrotation.
Diagnostic Tests & Interpretation
  • Anteroposterior, oblique, and true lateral views of the hand usually are sufficient.
  • Normally, the metacarpal neck is situated with a baseline of 15 degrees of volar angulation. Ensure adequate visualization on the lateral view to evaluate the degree of fracture angulation.
  • A conservative rule for limits of acceptable angulation of the 2nd through 5th digits is 10–30. Thus, the 2nd digit can only tolerate 10 degrees of angulation (in addition to the baseline 15 degrees); the 5th metacarpal can accept 30 degrees above the baseline. Many other experts will tolerate a greater degree of angulation of the 5th metacarpal; this decision often is influenced by the particular activity or sport of the patient.
  • Degrees of acceptable angulation vary in current literature. For the index or long finger, some authors report that angulations of >15 degrees above baseline are not tolerated due to the lack of carpal metacarpal motion (1)[C]. Others report that for the ring finger up to 30 degrees of excessive angulation (above baseline) at the metacarpal neck is acceptable, and for the small finger, up to 40 degrees of excessive angulation (above baseline) at the 5th metacarpal neck is acceptable (3)[C],(2)[B].
Differential Diagnosis
  • Metacarpal head fracture
  • Metacarpal shaft fracture
  • Open fracture
  • MCP joint dislocation
  • MCP joint sprain
Ongoing Care
  • Fractures should remain splinted for a minimum of 3–4 wks.
  • Clinical healing is defined as no tenderness with palpation of the fracture site.
  • Once the splints are removed, begin range of motion work with emphasis on handgrip and manipulation strength. Key to prevent stiffness of the MCP joint.
Follow-Up Recommendations
  • For 2nd and 3rd metacarpal neck fractures, follow-up radiographs should be obtained in 5–7 days to monitor fracture alignment.
  • For 4th and 5th metacarpal neck fractures, follow-up radiographs should be taken at 7–10 days.
  • Perform follow-up visits at 2-wk intervals to monitor for malalignment, rotational deformity, angulation, and progress of healing.
Patient Monitoring
  • Return to sports participation recommended when there is pain-free range of motion and when strength approaches that of the contralateral hand.
  • In general, conservative guideline for return to contact sports with splint/orthotic protection is after 2–4 wks of immobilization. Some experts may allow immediate return to play with a protective cast or splint.
  • Use of orthotic protection during contact sports should continue for 8–10 wks after the initial injury.
Patient Education
  • Patients should be warned that despite reduction and splinting, loss of knuckle prominence may result.
  • After splint removal, educate patient on range of motion exercises to prevent MCP joint stiffness.
  • 815.04 Closed fracture of neck of metacarpal bone(s)
  • 815.14 Open fracture of neck of metacarpal bone(s)

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