Should the humerus and arm be positioned at a 90-degree angle using a sling for a surgical neck fracture of the humerus?

Positioning for Surgical Neck Fracture of the Humerus

For a surgical neck fracture of the humerus, the arm should not be positioned at a 90-degree angle in a sling, but rather should be immobilized with the arm in a neutral position using a posterior splint or back-slab method.

Optimal Positioning Rationale

The positioning of the arm after a surgical neck fracture of the humerus is critical for proper healing and minimizing pain. Based on available evidence, the following approach is recommended:

Recommended Immobilization Method

• Use a posterior splint/back-slab immobilization rather than positioning the arm at 90 degrees in a sling
• Keep the arm in a neutral position with minimal stress on the fracture site
• The posterior splint provides better pain relief in the first 2 weeks after injury 1

Positioning Details

• Patient should be in a sitting or supine position
• The arm should be kept in a neutral position alongside the body
• Avoid flexing the elbow to 90 degrees as this can increase stress on the fracture site
• Ensure the splint adequately supports the entire humerus

Evidence-Based Considerations

The AAOS guidelines for fracture management provide relevant insights, although they primarily address pediatric supracondylar fractures. The principles of immobilization can be applied to surgical neck fractures in adults:

• Studies show better pain relief with posterior splint/back-slab immobilization compared to collar and cuff (sling) positioning 1
• Positioning the arm at 90 degrees can potentially:
  1. Increase stress on the fracture site
  2. Lead to displacement of fracture fragments
  3. Cause more pain during the healing process

Treatment Algorithm

1. Initial Assessment:

   • Confirm surgical neck fracture diagnosis via radiographs
   • Assess for displacement (if displaced, surgical consultation may be needed)
   • Evaluate neurovascular status of the limb

2. For Non-Displaced or Minimally Displaced Fractures:

   • Apply posterior splint with arm in neutral position
   • Ensure the splint extends from axilla to just above the elbow
   • Maintain the arm alongside the body, not at 90 degrees

3. Follow-up Care:

   • Re-evaluate in 1-2 weeks with repeat radiographs
   • Assess for pain control and any signs of displacement
   • Transition to functional bracing after initial healing phase (typically 2-3 weeks)

Common Pitfalls to Avoid

1. Avoid hyperflexion of the elbow (90-degree positioning) as this can cause:

   • Increased pain
   • Potential vascular compromise
   • Risk of displacement of fracture fragments

2. Avoid inadequate immobilization:

   • Ensure the splint properly supports the entire fracture site
   • The splint should be secure but not constrictive

3. Avoid prolonged immobilization:

   • Extended immobilization can lead to stiffness and reduced function
   • Transition to gentle range of motion exercises after adequate healing

The PROFHER trial demonstrated no significant difference between surgical and nonsurgical treatment for many displaced proximal humeral fractures 2, suggesting that proper nonsurgical management with appropriate positioning can yield good outcomes for many patients with surgical neck fractures.