Summary

Olecranon fractures are common injuries (10% of upper limb fractures) that disrupt the extensor mechanism of the elbow. They occur from a direct blow (falling onto the point of the elbow) or an avulsion force from the triceps muscle. The hallmark sign is the patient's inability to actively extend the elbow against gravity. Because the fracture involves the articular surface of the ulnohumeral joint, anatomical reduction is required to prevent arthritis. Management usually involves surgery: Tension Band Wiring (TBW) for simple transverse fractures (converting distraction forces into compression) or Plate Fixation for comminuted/oblique fractures. Hardware irritation is a major problem, with up to 80% of patients requiring removal of metalwork. [1,2]

Key Facts

• Mechanism: Direct blow (comminuted) or Triceps avulsion (transverse).
• The "Straight Leg Raise" of the Arm: If the patient cannot extend the elbow against gravity, the extensor mechanism is disrupted (like a patella fracture). Surgery is mandatory.
• TBW Principle: A figure-of-8 wire on the dorsal surface converts the tensile force of the Triceps into a compressive force at the fracture site during flexion.
• Hardware Pain: The olecranon is subcutaneous. Wires back out and cause bursitis. Warn patients they will likely need a second operation to remove it.

Clinical Pearls

"Check the Ulnar Nerve": The nerve runs in the cubital tunnel right next to the medial side of the olecranon. Fixation (especially plates) or the injury itself can damage it. Document sensation in the little finger before you operate.

"Monteggia Variant": If the fracture is distal to the coronoid process, it is NOT a simple olecranon fracture. It is a Monteggia fracture-dislocation or Trans-olecranon fracture-dislocation. The Radial Head will be dislocated. Always check the radial head on X-ray.

                 OLECRANON FRACTURE
                        ↓
            UNDISPLACED? EXTENSOR INTACT?
            ┌───────────┴─────────────┐
           YES                       NO
        (Mayo I)                  (Mayo II/III)
           ↓                          ↓
    NON-OPERATIVE                COMMINUTED?
  (Splint 2 weeks)            ┌───────┴───────┐
   (Early ROM)               NO              YES
                         (Transverse)     (Oblique)
                             ↓                ↓
                            TBW             PLATE
                        (Wire Fix)        (Locking)

Note: In the very elderly low-demand patient with a non-reconstructable fracture, Excision and Triceps Advancement is a salvage option.

1. Conservative (Non-Operative)

• Indication: Undisplaced (<2mm gap). Triceps mechanism intact (can extend against gravity).
• Protocol:
  • Above Elbow Splint in 45-90 degrees flexion.
  • Start motion at 1-2 weeks.
  • No heavy resistance for 6 weeks.
• Risk: Secondary displacement (Triceps pull). Weekly X-rays needed.

2. Tension Band Wiring (TBW)

• Indication: Simple transverse fracture (Mayo IIA).
• The Construct:
  • Two parallel K-wires (1.6mm) drilled down the shaft.
  • Figure-of-8 wire (18G) looped through a drill hole in the ulna and around the K-wires.
  • Biomechanics: When the elbow flexes, the figure-of-8 tightens, compressing the fracture.
• Pros: Cheap, smaller incision.
• Cons: High re-operation rate for metalware removal (painful backing out).

3. Plate Fixation (ORIF)

• Indication: Comminuted (Mayo IIB), Oblique fracture, or Fracture-Dislocation (Mayo III). TBW will fail in comminuted bone (compresses the pieces into a collapse).
• Implant: Pre-contoured Locking Olecranon Plate.
• Technique: Placed dorsally. Screws aiming into the coronoid provide the best stability ("Home Run Screw").

4. Fragment Excision & Advancement

• Indication: Elderly (>75), Osteoporotic, unreconstructable comminution ("Bag of Bones").
• Technique: Remove the bone fragments. Suture the Triceps tendon directly into the exposed ulnar stump.
• Limit: Can only excise up to 50% of the olecranon without causing instability.

TBW vs Plate (Powell et al. 2017)

• RCT: Multicentre.
• Findings: No difference in function (DASH score) or ROM.
• Complications: TBW had significantly higher rate of hardware removal and "skin complications". Plate group cost more initially but less re-operations.
• Conclusion: Plates are becoming the standard of care even for simple fractures to avoid the second operation.

Excision ("Bag of Bones") (Gartsman et al.)

• Showed excellent functional results in elderly patients with excision of up to 50% of the olecranon. Low complication rate. Early mobilisation.

What is the "Funny Bone"?

The Olecranon is the bony point of your elbow. The triceps muscle (the big one on the back of your arm) attaches to it. When it breaks, the muscle pulls the bone chunk halfway up your arm.

Why can't I straighten my arm?

Because the lever arm is broken. The muscle contracts, but it's not connected to the forearm anymore.

The Operation (Wiring)

We use two metal pins and a loop of wire to pull the bone back down. It acts like a rubber band brace. When you bend your elbow, it squeezes the broken ends together to make them heal faster.

The Metalwork Problem

Because the bone is right under the skin, you will feel the wires. They might hurt when you lean on a table. In about 8 out of 10 people, we have to do a small second surgery later to take them out once the bone is healed.

Recovery

You can move the elbow immediately (within a few days). No heavy lifting for 6 weeks.

Q1: Explain the principle of Tension Band Wiring. A: It converts a distractive force (from the Triceps) into a compressive force at the fracture site. The figure-of-8 wire on the dorsal (tension) surface absorbs the tension, causing the articular (compression) surface to compress when the joint naturally flexes. It requires an intact compressive cortex (cannot be used in comminution).

Q2: What is the "Home Run Screw" in olecranon plating? A: It is the long intermedullary screw that passes through the proximal plate, down the axis of the ulna, engaging the coronoid process. This captures the ulnohumeral articulation and adds significant stability.

Q3: How much of the olecranon can be excised without causing instability? A: Up to 50%. The anterior band of the MCL attaches to the sublime tubercle (at the base of the coronoid), so excision of the proximal olecranon does not destabilize the joint as long as the coronoid/MCL are preserved.

(End of Topic)