Humeral Shaft Fracture

A humeral shaft fracture involves the diaphysis between the proximal and distal metaphyseal regions.

Unlike weight bearing long bone fractures, many humeral shaft fractures heal successfully with functional bracing because substantial angulation and shortening can be tolerated without major loss of upper limb function.

The radial nerve is intimately related to the posterior humeral shaft in the spiral groove and is the major neurovascular structure at risk.

AO/OTA classification

Humeral shaft fractures are coded 12.

12A: Simple

• Spiral
• Oblique
• Transverse

12B: Wedge

• Spiral wedge
• Bending wedge
• Fragmented wedge

12C: Multifragmentary

• Complex spiral
• Segmental
• Irregular multifragmentary

Fractures are also described according to proximal, middle or distal third location.

Holstein Lewis fracture

A spiral fracture of the distal third of the humeral shaft.

The distal fragment can trap or injure the radial nerve as it pierces the lateral intermuscular septum.

It therefore has a strong anatomical association with radial nerve palsy.

Patients present with arm pain, swelling, deformity and abnormal movement.

Inspect for an open wound.

Document radial nerve function before any manipulation.

Radial nerve motor examination:

• Wrist extension
• Finger MCP extension
• Thumb extension

Radial nerve sensory examination:

• Dorsal first web space

Also document median and ulnar nerve function and distal pulses.

Primary radial nerve palsy is commonly a neurapraxia and most closed injuries recover spontaneously.

A new radial nerve palsy after reduction or fixation is more concerning for entrapment or iatrogenic injury.

Obtain AP and lateral radiographs of the entire humerus including shoulder and elbow.

CT is not routinely required for isolated shaft fractures.

Obtain vascular imaging when pulse, perfusion or examination suggests arterial injury.

Nonoperative treatment

Functional bracing remains an appropriate treatment for many closed humeral shaft fractures.

Initial treatment:

• Coaptation splint or hanging arm support during acute swelling

Then transition after approximately 7 to 14 days to:

• Functional Sarmiento brace

Allow early elbow and shoulder movement.

Commonly accepted alignment tolerances include approximately:

• Less than 20° anterior angulation
• Less than 30° varus or valgus
• Less than 3 cm shortening

The shoulder compensates for modest deformity well.

Monitor serial radiographs.

A fracture that progressively distracts or remains grossly unstable despite bracing requires operative reconsideration.

Operative indications

Strong indications include:

• Open fracture requiring debridement and stabilisation
• Vascular injury
• Floating elbow
• Bilateral humeral fractures
• Polytrauma requiring dependable mobilisation
• Segmental fracture
• Pathological fracture
• Inability to maintain acceptable alignment
• Failure of nonoperative treatment
• Symptomatic nonunion

Relative indications include:

• Severe obesity or body habitus making bracing ineffective
• Large breast tissue preventing brace control
• Long spiral fracture with persistent distraction
• Need for immediate upper limb weight bearing

Plate fixation

ORIF with plate and screws provides direct reduction and high union rates.

It is particularly useful for:

• Distal third fracture
• Radial nerve exploration
• Segmental pattern
• Fracture with vascular injury
• Nonunion

Simple fractures can receive compression fixation.

Comminuted fractures can be bridged to preserve biology.

Identify and protect the radial nerve when the surgical approach places it at risk.

Intramedullary nailing

Useful for:

• Segmental fracture
• Pathological fracture
• Severe soft tissue compromise
• Selected polytrauma

Potential disadvantages include shoulder pain and rotator cuff injury with antegrade insertion.

Radial nerve palsy

Primary radial nerve palsy accompanying a closed humeral shaft fracture is usually observed initially because spontaneous recovery is common.

Provide:

• Wrist extension splint
• Hand therapy
• Passive range of motion
• Serial neurological examination

Recovery often begins with:

• Brachioradialis
• Radial wrist extensors

then progresses to:

• Finger extension
• Thumb extension

If there is no clinical recovery, electrodiagnostic testing can be considered around 6 weeks.

If neither clinical nor electrodiagnostic recovery appears by approximately 3 months, nerve exploration and neurolysis should be considered.

Immediate or early radial nerve exploration is appropriate when:

• Open fracture
• Penetrating injury
• Associated vascular injury
• Radial nerve function is lost after manipulation or fixation
• Nerve transection is suspected
• Irreducible fracture suggests nerve interposition
• Severe neurogenic pain suggests entrapment.

Do not automatically explore every primary radial nerve palsy in a closed fracture.

Nonunion

Persistent motion, pain and lack of progressive healing require assessment for:

• Excessive fracture gap
• Instability
• Infection
• Smoking
• Metabolic abnormalities

Aseptic nonunion commonly requires compression plating with debridement of fibrous tissue and bone graft according to biology.

Postoperative management

Encourage early elbow and shoulder motion after stable fixation.

Weight bearing through the arm depends on construct stability and associated injuries.

Major complications include:

• Radial nerve palsy
• Nonunion
• Malunion
• Shoulder stiffness
• Elbow stiffness
• Infection
• Iatrogenic nerve injury
• Shoulder pain after antegrade nailing