What is the treatment for a displaced 5th metacarpal fracture?

Treatment of Displaced 5th Metacarpal Fracture

For displaced 5th metacarpal neck fractures (boxer's fractures), closed reduction with immobilization using either functional taping or casting is the preferred initial treatment, with surgical fixation reserved for fractures with >45° angulation, malrotation, or failed conservative management.

Initial Assessment and Treatment Thresholds

The decision between conservative and surgical management depends on specific radiographic parameters:

• Conservative treatment is appropriate when angulation is <30-45°, no malrotation is present, and shortening is <5mm 1
• Surgical intervention is indicated when displacement exceeds 45° in flexion and/or rotation is impaired 2
• Fractures with >30° displacement may warrant surgical treatment by intramedullary stabilization 1

Conservative Management Approach

Reduction Technique

For fractures requiring reduction, traction reduction is highly effective, correcting approximately 80% of initial sagittal plane angulation with minimal loss of correction (only 1° lost) during the 3-4 week casting period 3. This technique demonstrates superior efficacy and improved patient tolerance compared to other casting methods 3.

Immobilization Method

Functional taping is superior to cast immobilization for achieving faster functional recovery 4. A prospective randomized study demonstrated that functional taping results in significantly earlier return of mobility, power-grip, and strength compared to ulnar gutter plaster-cast splinting, with no difference in final outcomes at 6 months 4.

If casting is used, position the hand with:

• Full extension of fingers
• 60-90° flexion at the metacarpophalangeal joint 1
• Duration: 3-4 weeks 3

Early Mobilization

Active finger motion exercises should begin immediately following diagnosis to prevent stiffness 5. Movement of uninvolved fingers through complete range of motion is essential to prevent complications 5.

Surgical Management

When surgical intervention is necessary:

Technique Selection

Intramedullary K-wire fixation remains the reference technique over locking plates 2. A comparative study showed that K-wire fixation with 6 weeks' immobilization paradoxically provided better mobility outcomes than locking plates with immediate mobilization (98% vs 59% of healthy-side metacarpophalangeal flexion) 2.

Surgical Indications

• Closed reduction with percutaneous pinning using image intensification for most displaced fractures 6
• Open reduction with multiple K-wire pinning for comminuted fractures or when closed restoration of articular surface is unfeasible 6
• Base fractures (intra-articular or extra-articular) require reduction and pinning as they are inherently unstable 6

Common Pitfalls

Avoid over-immobilization: Excessive immobilization leads to stiffness that is difficult to treat after fracture healing and may require multiple therapy visits or additional surgical intervention 5.

Closed reduction of displaced 5th metacarpal neck fractures is often unsuccessful when attempted without proper technique 1. Use traction reduction methods rather than simple manipulation 3.

Locking plates do not justify their extra cost: Despite theoretical advantages of immediate mobilization, they result in higher complication rates (including stiffness, head necrosis, delayed consolidation) and poorer mobility outcomes compared to K-wires 2.

Follow-up Protocol

• Radiographic evaluation at approximately 3 weeks to assess healing 5, 7
• Re-evaluation at time of immobilization removal to confirm adequate healing 5, 7
• Monitor for complications including wire migration (with K-wires), neurologic lesions, or stiffness 2