What is the treatment for a fracture of the 4th and 5th metacarpal head and neck?

Treatment of 4th and 5th Metacarpal Head and Neck Fractures

For minimally displaced or non-displaced 4th and 5th metacarpal neck fractures with angulation <30 degrees, shortening <5mm, and no rotational deformity, treat with early functional mobilization using a hand-based splint for approximately 3-4 weeks; surgical fixation is indicated when angulation exceeds 30 degrees, shortening exceeds 5mm, there is rotational malalignment, or intra-articular displacement is present. 1, 2

Initial Assessment

• Obtain 3-view radiographs (posteroanterior, lateral, and 45° semipronated oblique) to assess fracture displacement, angulation, shortening, and rotational alignment 3
• Specifically evaluate for: angulation degree, shortening distance, rotational deformity (check finger cascade with flexion), and articular involvement 1, 2
• Critical pitfall: Closed reduction of displaced 5th metacarpal neck fractures (boxer's fractures) is typically unsuccessful and should not be relied upon 1

Non-Operative Management Criteria

Treat conservatively if ALL of the following are met:

• Angulation <30 degrees 1, 2
• Shortening <5mm 1, 2
• No rotational displacement (or <10 degrees) 2
• No articular incongruency 2
• No significant soft tissue trauma 2

Non-Operative Treatment Protocol

• Use a hand-based functional splint that allows metacarpophalangeal joint, interphalangeal joint, and radiocarpal joint motion throughout treatment 4
• Average splint duration is 24 days, with most patients requiring 3-4 weeks maximum 2, 4
• If using cast immobilization (less preferred), position fingers in full extension with metacarpophalangeal joints flexed 60-90 degrees, but limit duration to prevent stiffness 1
• Early mobilization is critical - immobilization beyond 3-4 weeks is unnecessary and increases stiffness risk 2
• Patients can typically return to work immediately or within days with hand-based splinting 4

Surgical Indications

Proceed with surgical fixation when ANY of the following are present:

• Angulation >30 degrees 1, 2
• Shortening >5mm 1, 2
• Rotational malalignment >10 degrees 2
• Intra-articular displacement 2
• Open fractures 1
• Multiple metacarpal fractures 1

Surgical Options

• Available fixation methods include K-wires, screws, plates, or external minifixateur, with choice based on fracture pattern and surgeon preference 5, 2
• For displaced 5th metacarpal neck fractures with >30 degrees angulation, intramedullary stabilization is effective 1
• Select fixation constructs that can withstand early postoperative motion forces 5
• Early mobilization after surgical fixation is essential to prevent stiffness and restore function 5

Expected Outcomes

• Non-operative treatment with early mobilization achieves good to excellent results in 94-95% of cases 2
• Surgical fixation provides good to excellent results in 85% of cases 2
• Hand-based functional splinting maintains fracture reduction in 90% of patients (27/30) with no change in alignment 4

Common Pitfalls to Avoid

• Do not attempt closed reduction of significantly displaced 5th metacarpal neck fractures - success rate is only 15% 2
• Avoid prolonged immobilization - this is the primary cause of post-treatment stiffness 5, 2
• Do not immobilize beyond 3-4 weeks even for fractures requiring initial stabilization 2
• When using braces for mobilization, monitor for local bruising and skin necrosis (3% complication rate) 2