Humeral Shaft Fracture Fixation (Plating vs Nailing)

Operative versus Conservative — The Central Decision

The default for an isolated, closed humeral shaft fracture with acceptable alignment is non-operative treatment in a functional (Sarmiento) brace. The humerus is a non-weight-bearing bone surrounded by generous soft tissue, and the shoulder and elbow compensate for residual deformity, so union rates with bracing are high (commonly quoted around 90% in classic series) with good functional outcomes.

Acceptable Alignment (limits in a brace)

• Up to about 20 degrees anterior angulation
• Up to about 30 degrees varus/valgus angulation
• Up to about 3 cm shortening
• Rotational malalignment is also generally well tolerated

Deformity within these limits is cosmetically and functionally acceptable; it is failure to maintain these limits — not minor in-range angulation — that triggers operative conversion.

Functional Bracing Protocol (Sarmiento)

• Initial management in a coaptation (U-slab) splint or hanging cast for 1-2 weeks to settle pain and swelling
• Transition to a prefabricated functional brace once acute swelling subsides
• The brace works by soft-tissue compression (hydraulic effect) maintaining alignment while gravity provides traction; early shoulder pendulum and elbow motion are encouraged
• Weekly radiographs initially to confirm alignment stays within acceptable limits
• Brace continued until clinical and radiographic union (typically 8-12 weeks)

Operative Indications

Patient/injury factors that mandate or favour surgery:

• Open fracture (debridement plus stabilisation)
• Vascular injury requiring repair — stabilise the bone to protect the vascular reconstruction
• Polytrauma — fixation permits early mobilisation, frees the limb for weight-bearing through aids, and aids nursing
• Floating elbow (ipsilateral humeral and forearm fracture)
• Bilateral humeral shaft fractures (bracing both is impractical)
• Pathological or impending pathological fracture
• Segmental fracture
• Failure to maintain acceptable reduction in a brace (loss of position beyond the limits above)
• Inability to tolerate or comply with bracing (e.g. large body habitus, significant breast/soft-tissue interposition, cognitive or social factors)
• Selected radial nerve palsies — open injury, after penetrating trauma, or a palsy that develops after closed reduction/manipulation (explore)

Radial Nerve Palsy — Decision Logic

• Primary palsy in a closed fracture: observe. About 90% are neuropraxia/axonotmesis that recover spontaneously by 3-4 months. Baseline examination, splint the wrist/fingers to prevent contracture, and obtain EMG/NCS at around 6 weeks and 3 months to track recovery.
• Secondary palsy (after reduction/manipulation): explore — the nerve may be entrapped in the fracture or have been injured by the manoeuvre.
• Open fracture or penetrating trauma with palsy: explore the nerve at the time of debridement/fixation.

Key Evidence

Surgical Anatomy of the Humeral Shaft

Radial Nerve — the Key Structure

• The radial nerve is a continuation of the posterior cord of the brachial plexus
• It enters the posterior compartment, descending in the spiral (radial) groove on the posterior humerus with the profunda brachii artery, between the lateral and medial heads of triceps
• It crosses from medial to lateral at roughly the middle/distal third junction
• It then pierces the lateral intermuscular septum about 10 cm proximal to the lateral epicondyle, entering the anterior compartment between brachialis and brachioradialis
• In the distal arm it lies anterior to the lateral epicondyle before dividing into superficial (sensory) and deep (posterior interosseous) branches
• Surgical relevance: directly against bone in the groove (posterior approach risk); tented over the lateral septum distally (Holstein-Lewis risk)

Other Structures

• Brachial artery and median/ulnar nerves: lie medially in the neurovascular bundle — at risk with a medial approach (rarely used) and in penetrating trauma
• Musculocutaneous nerve: supplies biceps/brachialis, lies in the anterior compartment — protected by working lateral to brachialis
• Axillary nerve: more proximal, wraps the surgical neck — relevant to proximal extension and antegrade nail entry
• Deltoid insertion: at the deltoid tuberosity (mid-shaft, lateral) — a landmark splitting proximal and distal halves

Surgical Approaches

Anterolateral Approach

• Best for: proximal and middle-third shaft fractures; extensile (can be extended distally as a Henry-type approach)
• Internervous plane proximally: between deltoid and pectoralis major; distally split brachialis (lateral half = radial nerve, medial half = musculocutaneous nerve — the dual innervation protects against complete denervation)
• Position: supine, arm on a table
• Radial nerve: must be identified distally where it crosses laterally — protect it as the brachialis is split
• Advantages: familiar, supine positioning, good for MIPO

Posterior Approach

• Best for: distal-third shaft fractures and access to the distal humerus
• Two main variants:
  • Triceps-splitting: split between/through the triceps heads — the radial nerve MUST be identified and protected in the spiral groove proximally; limited proximal extension because the nerve crosses the field
  • Paratricipital (Gerwin/triceps-sparing modification): work around the medial and lateral borders of triceps, mobilising the radial nerve, allowing more proximal extension without splitting the muscle
• Position: lateral decubitus or prone, arm over a bolster
• Radial nerve: the defining hazard — always identify it before applying a posterior plate

MIPO (Minimally Invasive Plate Osteosynthesis) — Anterolateral

• Concept: an extraperiosteal plate slid submuscularly along the anterior humerus through proximal and distal windows, preserving fracture-site biology
• Plane: anterior surface, deep to brachialis proximally; the distal window is made carefully to protect the radial nerve as it crosses laterally
• Advantages: less soft-tissue stripping, preserves periosteal blood supply, lower reported radial nerve injury when the distal window technique is respected
• Caution: still requires awareness of the radial nerve at the distal window; not ideal for very distal fractures

Compression Plating — the Reference Standard

Principles

• Open reduction and internal fixation with a compression plate (typically a 4.5 mm broad/narrow LC-DCP or locking compression plate)
• Aim for absolute stability in simple (transverse/short oblique) patterns — anatomical reduction and interfragmentary compression (lag screw plus neutralisation plate, or dynamic compression through the plate)
• Aim for relative stability (bridge plating) in comminuted/segmental patterns — restore length, alignment and rotation while preserving fracture-site biology
• Minimum fixation: aim for at least 6 cortices (3 bicortical screws) on each side of the fracture; more in osteopenic or comminuted bone

Steps (anterolateral example)

1. Position and approach: supine; anterolateral approach to the relevant shaft level
2. Expose and protect the radial nerve where it crosses (mandatory in distal-third and posterior approaches)
3. Reduce the fracture — restore length, alignment, rotation; use a lag screw across simple oblique/spiral patterns
4. Apply the plate — compression for simple patterns, bridging for comminuted; ensure adequate screw purchase each side
5. Confirm reduction, alignment, rotation and hardware position on fluoroscopy; re-check radial nerve is free and uninjured
6. Close in layers; the nerve must not be kinked over the plate edge

Advantages of Plating

• Lower nonunion and lower reoperation in pooled data versus nailing
• No shoulder violation — spares the rotator cuff
• Allows direct radial nerve exploration — the technique of choice when the nerve must be inspected (open injury, post-manipulation palsy)
• Best for distal-third fractures

Intramedullary Nailing

Principles

• Load-sharing intramedullary device; biologically favourable as it can be placed with limited fracture-site exposure
• Antegrade (proximal entry through the rotator cuff/humeral head) or retrograde (distal posterior entry just above the olecranon fossa)
• Locking screws proximally and distally control length and rotation
• Particularly suited to pathological, impending, segmental and osteopenic fractures and the polytrauma patient

Antegrade vs Retrograde Entry

• Antegrade: entry at the medial edge of the supraspinatus footprint, just off the articular margin; the chief drawback is rotator cuff / shoulder pain and impingement — meticulous cuff repair and a buried nail are essential
• Retrograde: entry through the posterior distal humerus proximal to the olecranon fossa; avoids the shoulder but risks a supracondylar fracture / distal cortex blow-out at the entry site and is unsuitable for very distal fractures

Advantages of Nailing

• Load-sharing and biology-preserving (less periosteal stripping)
• Good for pathological/segmental fractures and prophylactic fixation
• Smaller incisions, useful in the polytrauma setting

Why Meta-analyses Favour Plating

• Lower reoperation rate and lower shoulder complication rate with plating
• Antegrade nailing in particular is associated with shoulder pain and impingement
• Nailing is associated with higher rates of shoulder stiffness and, in some series, nonunion at the fracture/distal locking site

Key Evidence

Post-operative Protocol

Early Phase (Day 0-14)

• Sling for comfort for the first days after fixation; encourage early controlled motion as stability permits
• Wound care: standard; monitor for haematoma and infection, especially in open fractures
• Radial nerve check: document distal radial nerve function in recovery and at first review — distinguish a new (iatrogenic) deficit from a pre-existing one
• Analgesia: multimodal; regional blocks can transiently mask a nerve deficit, so document baseline before block where feasible
• Radiographs: post-operative AP and lateral to confirm reduction, alignment, rotation and hardware position

Rehabilitation

• Stable plate fixation: early active-assisted shoulder and elbow range of motion within days; progress to active motion as pain allows
• Nailing: protect the shoulder after antegrade nailing while the cuff repair heals; begin pendulum and gentle ROM, advancing per surgeon protocol
• Functional bracing (non-operative): pendulum exercises and elbow ROM early; brace maintained until union (8-12 weeks); avoid loading the brace edge
• Strengthening: introduced once union is progressing and motion restored, usually from 6-8 weeks onwards
• Return to function: light activity early; heavier loading and contact/manual work deferred until radiographic union (commonly 10-16 weeks)

Radial Nerve Palsy Rehabilitation

• Splinting: dynamic or static wrist/finger extension (cock-up) splint to prevent flexion contracture while awaiting recovery
• Therapy: maintain passive ROM of wrist and fingers; active assisted as recovery returns
• Monitoring: serial clinical exam; advancing Tinel's sign down the forearm signals regeneration; EMG/NCS at about 6 weeks and 3 months
• Recovery expectation: first sign is usually return of brachioradialis/wrist extension, then finger and thumb extension; about 90% of primary closed palsies recover by 3-4 months
• No recovery by 3-4 months / failure on EMG: proceed to exploration; if the nerve is not reconstructable, plan tendon transfers (e.g. PT to ECRB, FCR/FCU to EDC, PL to EPL)

Special Case: Pathological and Impending Fracture

Assessment

• Suspect in a fracture from low-energy trauma, with a lytic/blastic lesion, or in a known cancer/myeloma patient
• Stage and diagnose before fixing: imaging of the whole bone, staging (CT chest/abdomen/pelvis, bone scan), and biopsy if the primary is unknown — never internally fix a presumed metastasis without a tissue diagnosis if the primary is unknown (could be a primary bone sarcoma)
• Use a scoring tool (e.g. Mirels) for impending fractures to decide on prophylactic fixation

Fixation Choice

• Intramedullary nailing is often preferred for diaphyseal metastatic/impending lesions — load-sharing, protects the whole bone length, allows immediate use, and avoids extensive exposure of irradiated/tumour-bearing tissue
• Consider cement augmentation of the lesion and adjuvant radiotherapy post-operatively
• Plate plus cement or endoprosthetic reconstruction is used for extensive bone loss or peri-articular disease
• Goals are durable pain-free function for the patient's expected survival, not necessarily biological union

Special Case: Nonunion

Risk Factors

• Distal-third location, transverse pattern, distraction, inadequate immobilisation/fixation, smoking, NSAIDs, infection, open injury, and patient comorbidity
• The distal-third transverse fracture is the classic humeral nonunion

Management

• Confirm/exclude infection (inflammatory markers, consider deep sampling)
• Gold-standard treatment: revision open reduction with compression plating (correct any distraction, achieve absolute stability) plus autologous bone graft (e.g. iliac crest) for atrophic patterns
• Address mechanical and biological causes; consider exchange from a nail to a compression plate where a nail has failed to control the nonunion