Should a sling be used with the elbow in a 90-degree flexed position for a surgical neck of humerus fracture?

Positioning the Elbow in a Sling for Surgical Neck of Humerus Fracture

For a surgical neck of humerus fracture, the elbow should be positioned in a neutral position rather than fixed at 90 degrees flexion in the sling to optimize healing and functional outcomes.

Rationale for Neutral Position Sling

The evidence supports using a neutral position sling rather than a traditional 90-degree flexed position for several key reasons:

1. Improved Clinical Outcomes

   • A randomized study demonstrated that patients treated with a custom neutral-position shoulder and elbow sling for 30 days after surgical fixation showed significantly improved pain scores (VAS) and better shoulder function (Constant-Murley scores) compared to traditional sling positioning 1.
   • The neutral position reduces stress on the fracture site while maintaining better alignment of the humeral fragments.

2. Reduced Risk of Complications

   • Neutral positioning helps prevent:
     • Internal fixation failure
     • Vascular compromise that can occur with excessive elbow flexion
     • Stiffness from prolonged immobilization in a non-anatomic position

Post-Surgical Management Algorithm

1. Initial Immobilization (0-2 weeks)

   • Use a custom neutral-position shoulder and elbow sling
   • Maintain the arm close to the body without forced 90-degree elbow flexion
   • Allow gentle finger and wrist motion to prevent edema

2. Early Rehabilitation (2-4 weeks)

   • Begin gentle pendulum exercises while maintaining sling support
   • Continue neutral position sling wear between exercises
   • Avoid above chest level activities until fracture healing is evident 2

3. Progressive Rehabilitation (4+ weeks)

   • Gradually discontinue sling use based on fracture healing
   • Begin progressive range-of-motion exercises including shoulder, elbow, wrist, and hand motion
   • The sling should be worn for comfort only and may be discarded as early as the patient's pain allows 2

Important Considerations

• Avoid Hyperflexion: Positioning the elbow at 90 degrees can create excessive tension on the fracture site and potentially compromise blood supply
• Prevent Stiffness: Early finger and hand motion is essential even during immobilization to prevent edema and stiffness 2
• Monitor Healing: Above chest level activities should be restricted in both operative and non-operative management until fracture healing is evident 2
• Avoid Aggressive Therapy: Overly aggressive physical therapy may increase the risk of fixation failure in the postoperative period 2

Clinical Pitfalls to Avoid

1. Prolonged Immobilization: Extended immobilization in any position increases the risk of shoulder stiffness and delayed rehabilitation
2. Ignoring Early Motion: Failure to initiate early finger and hand motion can lead to significant stiffness and edema
3. Improper Sling Positioning: Traditional slings that force 90-degree elbow flexion may place unnecessary stress on the fracture site
4. Overly Aggressive Rehabilitation: Starting too much motion too early can compromise healing and fixation

The evidence clearly demonstrates that a neutral position sling provides superior outcomes for surgical neck of humerus fractures compared to traditional 90-degree flexed positioning, with improved pain scores, better functional outcomes, and reduced complication rates.