Proximal Humerus Fracture

A proximal humerus fracture involves the humeral head, anatomical neck, surgical neck or tuberosities.

Most occur in older adults after low energy falls and are fragility fractures.

In younger patients, high energy mechanisms can produce fracture dislocations, head split injuries and major tuberosity displacement.

The principal determinants of treatment are:

• Displacement
• Number of major fragments
• Tuberosity position
• Medial calcar integrity
• Head viability
• Bone quality
• Age and physiological demand
• Associated dislocation

Neer classification

Based on four potential segments:

• Humeral head or articular segment
• Greater tuberosity
• Lesser tuberosity
• Humeral shaft

A segment counts as a separate displaced part when displaced by approximately:

• More than 1 cm

or

• More than 45° angulation

The greater tuberosity is often treated with a lower displacement threshold because even approximately 5 mm superior displacement can cause impingement and altered rotator cuff mechanics.

One part fracture

No segment meets displacement criteria, regardless of the number of fracture lines.

Most proximal humeral fractures fall into this category.

Two part fracture

One segment is displaced relative to the others.

Examples:

• Surgical neck
• Anatomical neck
• Greater tuberosity
• Lesser tuberosity

Three part fracture

Two segments are displaced, commonly:

• Surgical neck plus greater tuberosity

or

• Surgical neck plus lesser tuberosity

Four part fracture

The head, greater tuberosity, lesser tuberosity and shaft are all separated as displaced segments.

These injuries have a much higher risk of humeral head ischaemia.

Fracture dislocation

The head fragment is dislocated from the glenoid in addition to the fracture.

Head split fracture

The articular surface itself is divided.

Head viability factors

Risk of humeral head ischaemia increases with:

• Anatomical neck fracture
• Disruption of the medial soft tissue hinge
• Short metaphyseal head extension, particularly below approximately 8 mm
• Severe displacement
• Four part configuration.

Patients have shoulder pain, swelling and inability to move the arm.

Ecchymosis can extend extensively down the arm and chest over several days.

Inspect for:

• Open injury
• Skin tenting
• Shoulder contour suggesting dislocation
• Massive swelling

Assess axillary nerve function carefully:

• Sensation over the lateral deltoid region
• Deltoid contraction when clinically possible

Also assess:

• Radial pulse
• Capillary refill
• Radial, median and ulnar nerve function

A palpable pulse does not completely exclude axillary artery injury because collateral circulation around the shoulder can preserve distal perfusion.

Obtain the shoulder trauma series:

• True AP
• Scapular Y
• Axillary lateral where tolerated

CT is useful for:

• Three and four part fractures
• Head split injury
• Fracture dislocation
• Tuberosity morphology
• Surgical planning

Do not repeatedly manipulate a suspected fracture dislocation without adequate imaging and orthopaedic preparation.

Nonoperative treatment

Most minimally displaced proximal humerus fractures are treated without surgery.

Use a sling for comfort.

Prolonged immobilisation produces severe shoulder stiffness.

Stable impacted fractures typically require only approximately 2 to 3 weeks of sling support before progression of gentle range of motion. Resistance exercises generally begin later, around 6 weeks as healing progresses.

Start:

• Hand and elbow movement immediately
• Pendulum exercises when pain permits
• Passive assisted shoulder movement
• Active movement after early union

Greater tuberosity fracture

A minimally displaced fragment can be treated in a sling.

Consider fixation when displacement exceeds approximately 5 mm, especially superior or posterior displacement that will impair rotator cuff mechanics.

In very high demand overhead athletes, smaller displacement may be clinically important.

Displaced two part surgical neck fracture

Treatment depends on:

• Age
• Bone quality
• Degree of translation
• Angulation
• Medial hinge
• Functional demand

ORIF is appropriate for significantly displaced unstable fractures in physiologically suitable patients.

Fixation options include:

• Locking plate
• Intramedullary nail in selected surgical neck patterns
• Percutaneous techniques for selected simple fractures

Reduction must restore the medial calcar and avoid varus. Varus malalignment increases fixation failure.

Three part fracture

In younger patients with reconstructable fragments, ORIF is usually preferred.

The tuberosities must be anatomically restored because rotator cuff function depends on their position.

Heavy nonabsorbable sutures through:

• Supraspinatus
• Infraspinatus
• Subscapularis

can control tuberosity fragments and reduce stress on plate screws.

Four part fracture

Young patients may still undergo reconstruction when the head is viable and reconstructable.

In older patients, severe comminution, poor bone quality and high osteonecrosis risk often make arthroplasty more reliable than fixation.

Reverse shoulder arthroplasty

Increasingly used in older patients with:

• Nonreconstructible three or four part fracture
• Head split fracture
• Severe tuberosity comminution
• Poor bone quality
• Fracture dislocation not suitable for stable fixation

Its function is less dependent on perfect tuberosity healing than hemiarthroplasty, although tuberosity healing still improves rotational function.

Reverse arthroplasty is not automatically necessary for every complex fracture in an older patient. Some elderly patients obtain acceptable outcomes with nonoperative treatment, and the incremental benefit of arthroplasty can be modest in selected populations.

Hemiarthroplasty

Now has a more limited role.

Consider in younger or selected patients with an unreconstructible humeral head but:

• Intact rotator cuff
• Reconstructable tuberosities

Outcome depends heavily on anatomical tuberosity healing.

Fracture dislocation

Urgent reduction is required, but reduction should be performed carefully.

In displaced anatomical neck fracture dislocation, forceful closed manipulation risks further vascular compromise or head displacement. Open reduction may be safer.

Locking plate technical principles

Restore:

• Head shaft alignment
• Medial calcar
• Tuberosity position
• Version

Use inferomedial calcar support screws where possible.

Avoid placing the plate excessively superiorly because this causes subacromial impingement.

Confirm screw position in multiple fluoroscopic planes because intra articular screw penetration is a major complication.

Postoperative care

Stable fixation allows early protected shoulder motion.

Avoid prolonged immobilisation.

Progressive strengthening follows evidence of fracture healing.

Major complications include:

• Shoulder stiffness
• Osteonecrosis
• Varus collapse
• Screw cut through or joint penetration
• Tuberosity nonunion or malposition
• Subacromial impingement
• Rotator cuff dysfunction
• Axillary nerve injury
• Infection
• Post traumatic arthritis