What is the recommended treatment for a comminuted lateral humeral head fracture with superior displacement of the lateral fragment?

Treatment of Comminuted Lateral Humeral Head Fracture with Superior Displacement

For a comminuted lateral humeral head fracture with superior displacement of the lateral fragment, hemiarthroplasty is the recommended treatment, particularly in elderly patients, as this fracture pattern represents a complex, displaced injury with high risk of avascular necrosis and poor outcomes with internal fixation. 1

Treatment Algorithm Based on Patient Age and Fracture Characteristics

Elderly Patients (>65-70 years)

Primary hemiarthroplasty is strongly recommended for comminuted humeral head fractures with significant displacement. The evidence consistently demonstrates that:

• Hemiarthroplasty achieves superior outcomes (mean Constant score 74 points) compared to conservative treatment (54 points) or open reduction internal fixation (52 points) in four-part and severely comminuted fractures 2
• The comminuted nature with superior displacement indicates high risk of humeral head osteonecrosis, making prosthetic replacement the preferred option 1, 2
• Patient satisfaction is high, with 19 of 21 patients (90%) satisfied with prosthetic outcomes and willing to undergo the same procedure again 3

Younger, Active Patients (<50-60 years)

The treatment becomes more nuanced:

• Attempt open reduction and internal fixation (ORIF) with locking plate osteosynthesis if the humeral head fragment has adequate bone stock and vascular supply appears preserved
• However, be aware that ORIF is associated with considerable complications in comminuted fractures 4
• Consider reverse shoulder arthroplasty if there is pre-existing rotator cuff dysfunction or if ORIF fails 4, 5

Critical Decision Points

When to Choose Hemiarthroplasty Over ORIF:

1. Four-part fracture pattern or severe comminution
2. Osteoporotic bone quality where internal fixation will likely fail 6
3. Superior displacement >1cm suggesting vascular compromise
4. Patient age >70 years with lower functional demands 3, 7
5. Fracture-dislocation pattern 8

Surgical Technique Considerations:

• Use a Neer II modular shoulder prosthesis or equivalent modern system 3
• Anatomic reconstruction of the tuberosities is critical - the outcome of hemiarthroplasty is closely related to tuberosity healing 4
• Ensure proper prosthetic height and version to optimize deltoid function
• Early functional physiotherapy is essential after prosthetic replacement 6

Common Pitfalls to Avoid

1. Attempting ORIF in osteoporotic bone with severe comminution - this leads to fixation failure, reoperation, and worse outcomes than primary arthroplasty 2

2. Underestimating the risk of avascular necrosis - comminuted fractures with displacement have compromised vascular supply; the humeral head blood supply enters through the rotator cuff attachments, which are disrupted in these injuries

3. Delaying surgery excessively - while not an absolute emergency, prolonged delay makes reduction more difficult and increases soft tissue contracture

4. Poor tuberosity fixation during arthroplasty - this is the most common cause of poor functional outcomes after hemiarthroplasty; use heavy non-absorbable sutures through bone tunnels

Alternative: Reverse Shoulder Arthroplasty

Reverse shoulder arthroplasty may provide superior outcomes in geriatric patients, especially those with:

• Pre-existing rotator cuff dysfunction 4
• Failed primary hemiarthroplasty 5
• Inability to achieve adequate tuberosity healing

Reverse arthroplasty compensates for rotator cuff deficiency by relying on deltoid function and provides more predictable functional outcomes in elderly patients 5.

Expected Outcomes

With appropriate treatment selection:

• Hemiarthroplasty: Mean Constant score 48-74 points at 16 months, with 90% patient satisfaction 3, 2
• ORIF in three-part fractures: Mean Constant scores 83-91 points when successful 2
• Conservative treatment: Generally poor outcomes (mean 54 points) and should be avoided in displaced, comminuted fractures 2

The key is matching the treatment to the fracture pattern, bone quality, and patient physiologic age rather than chronologic age alone.