Summary

Humeral shaft fractures account for 3-5% of all adult fractures. They represent a unique orthopaedic condition where conservative management (Functional Bracing) remains the Gold Standard for the majority of isolated injuries, achieving >95% union rates with excellent function. The Sarmiento Brace utilizes the hydrostatic pressure of the thigh muscles to stabilize the fracture while allowing joint motion. However, absolute indications for surgery include Open Fractures, Vascular Injury, and Polytrauma. The Radial Nerve (running in the spiral groove) is at high risk, particularly in distal 1/3 spiral fractures (Holstein-Lewis). [1,2,3]

Key Facts

• Most Common Nerve Injury: Radial Nerve (11-18%). Causes Wrist Drop.
• Acceptable Deformity: The shoulder (ball-and-socket) compensates well. We accept:
  • 20° Anterior/Posterior Angulation.
  • 30° Varus/Valgus.
  • 3cm Shortening.
• Prognosis: 90% of Radial Nerve palsies are neuropraxias and resolve spontaneously in 3-4 months.

Clinical Pearls

"The Wrist Drop Rule": ALWAYS document wrist extension before touching the patient. If they have a palsy before reduction, we observe. If they develop a palsy after reduction, the nerve may be entrapped -> SURGERY.

"Gravity is the Aligning Force": In a cast or brace, the arm MUST hang freely. If the patient rests their elbow on a chair armrest, they push the humerus up, causing Varus deformity.

"The Floating Elbow": Humerus Fracture + Forearm Fracture. This mechanical linkage is unstable ("flail"). Plating the humerus is mandatory to stabilize the limb.

                 HUMERAL SHAFT FRACTURE
                          ↓
             OPEN? VASCULAR? POLYTRAUMA?
             ┌────────────┴─────────────┐
            YES                         NO
             ↓                          ↓
         EMERGENCY               ISOLATED INJURY?
          SURGERY                       ↓
      (Debride + Fix)         ┌─────────┴──────────┐
                          ACCEPTABLE             UNACCEPTABLE
                           ALIGNMENT?             ALIGNMENT?
                   (<20° AP, <30° Varus)      (after reduction)
                              ↓                        ↓
                         CONSERVATIVE               SURGERY
                      (Sarmiento Brace)         (Plate/Nail)

1. Conservative (Sarmiento Protocol) - GOLD STANDARD

• Phase 1 (Weeks 0-2): Hanging Cast (U-Slab).
  • Weight of cast provides traction.
  • Patient must sleep semi-upright.
• Phase 2 (Weeks 2-10): Functional Brace.
  • Plastic shell.
  • Concept: Hydrostatic compression of soft tissues stabilizes the bone cylinder.
  • Motion: Early elbow/shoulder motion encouraged.
• Outcome: >95% union. Minimal functional loss.

2. Surgical Fixation (ORIF)

• Indications:
  • Open fractures.
  • Vascular injury.
  • Floating Elbow.
  • Polytrauma (needs to use arms for crutches/transfer).
  • Failure of brace (Non-union).
  • Pathological fracture.
• Technique: Compression Plating (4.5mm LCP). Minimally 6 cortices (3 screws) above and below.
• Approach: Anterolateral (Proximal) or Posterior (Distal).

3. Intramedullary Nailing

• Indication: Pathological fractures (metastasis in whole bone).
• Pros: Small incision. Load sharing.
• Cons: Rotator Cuff Pain (Antegrade nail violates the cuff). Lower union rate than plating.

The FISH Trial (Wait... FISH is Humerus Shaft?)

• Clarification: There was a trial "Surgery vs Functional Bracing" (JAMA 2020).
• Findings: No difference in DASH scores at 12 months. Surgery had higher complication rate (nerve injury, infection) but faster emotional recovery.
• Conclusion: Supports bracing as standard of care.

Sarmiento's Original Series

• Proved that rigid immobilization is unnecessary. Function (motion) promotes healing (callus).

What is the plan?

We are going to treat this with a brace. It feels counter-intuitive because the bone moves a little bit, but the humerus loves movement. It heals with a big ball of "bone glue" (callus).

Why no surgery?

Surgery involves a huge cut and risks damaging the main nerve to your hand. The brace gives the same end result without the risks.

The Nerve (If Palsy)

Your nerve is bruised. It acts like a stunned electrical cable. It usually wakes up, but it grows back very slowly (1mm a day). It might take 3 months before you can lift your wrist. We will wait.

Sleeping

You must sleep sitting up (in a recliner or with pillows) for the first 2-3 weeks. If you lie flat, gravity stops pulling the bone straight and it creates pain.

Q1: What are the absolute indications for surgery in a Humeral Shaft Fracture? A: Open fracture, Vascular injury requiring repair, Floating Elbow (ipsilateral forearm fracture), Brachial Plexus injury, Compartment Syndrome.

Q2: Describe the management of a Radial Nerve Palsy presenting AFTER manipulation? A: This is one of the few indications for early exploration. The nerve may have been entrapped in the fracture site during the reduction maneuver.

Q3: Why is IM Nailing less preferred than Plating for the Humerus? A: IM Nailing (Antegrade) violates the rotator cuff insertion, leading to permanent shoulder pain and stiffness in a significant number of patients. Plating avoids the joint entirely. Plating also has higher union rates.

(End of Topic)