Humerus Fracture Symptoms: What to Look For & How to Heal

Introduction & Epidemiology

Humerus fractures represent a significant portion of upper extremity trauma, encompassing breaks in the proximal, diaphyseal, and distal regions of the humerus. These injuries present a diverse spectrum, ranging from low-energy falls in osteoporotic elderly individuals to high-energy trauma in younger populations. Understanding the epidemiology and general characteristics of these fractures is paramount for appropriate management.

Proximal humerus fractures (PHF) constitute approximately 5% of all fractures and are the third most common fracture in the elderly, predominantly affecting women over 60 years of age with a direct correlation to decreasing bone mineral density and osteoporosis. Their incidence is projected to increase with an aging global population. While most are displaced, only a minority require surgical intervention.

Diaphyseal humerus fractures account for 1-3% of all fractures. The incidence exhibits a bimodal distribution: high-energy trauma (e.g., motor vehicle accidents, direct blows) in younger, active individuals, and low-energy falls in older, osteoporotic patients. Associated radial nerve palsy is a critical concern, occurring in up to 18% of cases, primarily with spiral or transverse fractures.

Distal humerus fractures are less common, comprising 2-7% of all fractures in adults and approximately 30% of elbow fractures. Similar to diaphyseal fractures, they show a bimodal distribution, affecting younger males via high-energy trauma and older osteoporotic females via low-energy falls. Intra-articular involvement is common, demanding meticulous anatomical reduction and stable fixation to preserve elbow function.

Management decisions for humerus fractures are complex, influenced by fracture morphology, patient age, bone quality, functional demands, associated injuries (neurovascular, soft tissue), and surgeon expertise. While many can be managed non-operatively, a significant subset necessitates surgical intervention to optimize outcomes and prevent complications such as nonunion, malunion, or loss of function.

Surgical Anatomy & Biomechanics

A thorough understanding of the surgical anatomy and biomechanical forces acting on the humerus is fundamental for effective operative planning and execution.

Proximal Humerus

The proximal humerus is a complex region comprising the humeral head, anatomical neck, surgical neck, greater tuberosity, and lesser tuberosity.
* Humeral Head: Articulates with the glenoid, providing mobility. The articular surface is retroverted approximately 30 degrees and angled approximately 130-145 degrees relative to the humeral shaft.
* Tuberosities: The greater tuberosity serves as the insertion site for the supraspinatus, infraspinatus, and teres minor, while the lesser tuberosity anchors the subscapularis. These rotator cuff muscles exert significant deforming forces on fracture fragments.
* Vascularity: The humeral head receives its primary blood supply from the anterior and posterior circumflex humeral arteries, which form the arcuate artery (ascending branch of the anterior circumflex humeral artery) and posteromedial ascending arteries. The critical "watershed area" lies between the insertion of the joint capsule and the rotator cuff. Compromise of this blood supply, particularly with multifragmentary fractures (e.g., 4-part valgus-impacted fractures), significantly increases the risk of avascular necrosis (AVN).
* Nerves at Risk: The axillary nerve courses approximately 5-7 cm distal to the acromion, wrapping around the surgical neck of the humerus. It innervates the deltoid and teres minor, providing sensation over the lateral shoulder. Care must be taken to protect this nerve during deltopectoral and deltoid-splitting approaches.

Humeral Diaphysis

The humeral shaft extends from the surgical neck to the supracondylar ridges.
* Spiral Groove: Located on the posterior aspect of the midshaft, it provides passage for the radial nerve and profunda brachii artery.
* Muscle Attachments: The pectoralis major, deltoid, and latissimus dorsi insert proximally, while the triceps, biceps, and brachialis attach more distally. These muscles exert diverse deforming forces depending on fracture location. For example, fractures proximal to the pectoralis major insertion may result in abduction and external rotation of the proximal fragment due to rotator cuff pull, while fractures distal to the deltoid insertion may cause proximal fragment abduction and distal fragment medial displacement.
* Nerves at Risk: The radial nerve is the most commonly injured nerve in diaphyseal humerus fractures, particularly in the middle and distal thirds due to its intimate association with the spiral groove. It innervates the triceps, anconeus, brachioradialis, supinator, and wrist/finger extensors, providing sensation over the dorsum of the hand.

Distal Humerus

The distal humerus forms the elbow joint, a complex hinge joint.
* Articular Surface: Composed of the capitellum (lateral, articulates with radial head) and trochlea (medial, articulates with ulnar coronoid and olecranon). The trochlea is critical for elbow stability and motion.
* Epicondyles: The medial and lateral epicondyles serve as origins for forearm flexors/pronators and extensors/supinators, respectively.
* Fossae: The coronoid fossa anteriorly and the olecranon fossa posteriorly accommodate the coronoid process and olecranon, respectively, during elbow flexion and extension.
* Nerves at Risk: The ulnar nerve passes through the cubital tunnel posterior to the medial epicondyle. It innervates the flexor carpi ulnaris, ulnar half of flexor digitorum profundus, and most intrinsic hand muscles, providing sensation to the ulnar side of the hand. The median nerve and radial nerve are also at risk with significant displacement or open injuries.
* Vascularity: The brachial artery bifurcates into the radial and ulnar arteries just distal to the elbow joint. It is at risk, particularly with high-energy supracondylar or comminuted intra-articular fractures.
* Biomechanics: The distal humerus features two columns (medial and lateral) connected by the articular segment. This column theory is critical for stable surgical fixation. The trochlea's spool-like shape and the strong collateral ligaments provide inherent stability.

Indications & Contraindications

The decision for operative versus non-operative management of humerus fractures is multifactorial, balancing patient factors, fracture characteristics, and potential risks/benefits.

Non-Operative Indications

• Proximal Humerus:
  • Minimally displaced fractures (e.g., Neer 1-part fractures, or 2-part fractures with minimal displacement and angulation <45 degrees, less than 1 cm translation).
  • Stable impacted fractures.
  • Elderly, low-demand patients with significant comorbidities where surgical risks outweigh potential benefits, even with moderate displacement.
  • Patients with acceptable functional outcomes despite malunion.
• Diaphyseal Humerus:
  • Closed fractures with acceptable alignment (e.g., <20 degrees anterior angulation, <30 degrees varus/valgus, <20-30 degrees rotation, <3 cm shortening). Specific thresholds may vary.
  • Stable transverse, short oblique, or spiral fractures.
  • Patients with significant medical comorbidities precluding surgery.
  • Pathological fractures where non-operative management is aligned with palliative goals.
• Distal Humerus:
  • Non-displaced or minimally displaced extra-articular fractures (e.g., stable medial or lateral epicondyle fractures).
  • Elderly, very low-demand patients with severe osteoporosis and comminution where stable fixation is unlikely and function is prioritized over anatomical restoration.

Operative Indications

• Absolute Indications:
  • Open fractures (Gustilo-Anderson Type I-III).
  • Vascular injury requiring repair (often accompanied by neurological deficit).
  • Compartment syndrome.
  • Irreducible closed fractures or fracture-dislocations.
  • Progressive neurological deficit after reduction.
  • Pathological fractures for stabilization or tumor resection.
  • Polytrauma patients requiring stabilization for early mobilization.
• Relative Indications:
  • Proximal Humerus:
    • Displaced 2-part (surgical neck, anatomical neck, or tuberosity) fractures with significant angulation/translation.
    • Displaced 3-part or 4-part fractures (often considered for ORIF or arthroplasty).
    • Fracture-dislocations.
    • Failure of non-operative management (e.g., persistent pain, progressive displacement).
    • Young, active patients requiring anatomical reduction and early mobilization.
  • Diaphyseal Humerus:
    • Failure to achieve or maintain acceptable alignment with non-operative treatment.
    • Segmental fractures.
    • Floating elbow/shoulder.
    • Brachial plexus injury (to facilitate nursing care and improve functional outcomes, especially in flail arm).
    • Bilateral humerus fractures.
    • Pathological fractures (for prophylactic stabilization or following tumor excision).
    • Open fractures (after debridement).
    • Vascular injury repair necessitating stable fixation.
    • Delayed union or established nonunion.
  • Distal Humerus:
    • All displaced intra-articular fractures (e.g., C1-C3 AO/OTA types) requiring anatomical reduction and stable fixation.
    • Displaced articular segment fractures (capitellum, trochlea).
    • Displaced extra-articular fractures causing unacceptable angulation or shortening.
    • Open fractures.
    • Failure of non-operative management.

Contraindications

• Absolute Contraindications: Active infection in the surgical field (unless part of debridement), severe medical comorbidities precluding anesthesia (ASA Class IV/V where benefits do not outweigh risks), profound irreversible neurological injury (e.g., complete brachial plexus avulsion) where surgery adds no functional benefit.
• Relative Contraindications: Severe osteoporosis leading to poor hardware purchase (may lead to consideration of arthroplasty or alternative fixation), patient non-compliance, profound soft tissue damage precluding safe wound closure.

Operative vs. Non-Operative Indications Summary

Pre-Operative Planning & Patient Positioning

Meticulous pre-operative planning is critical for optimizing surgical outcomes and minimizing complications.

Pre-Operative Planning

1. Patient Assessment: A comprehensive medical evaluation is essential to assess comorbidities, optimize existing conditions, and determine anesthetic risk. Neurovascular status of the injured extremity must be thoroughly documented pre-operatively. Skin integrity, presence of open wounds, or impending soft tissue compromise dictates urgency and approach.
2. Imaging:
   • Standard Radiographs: True AP, lateral, and axillary views (for proximal humerus), or AP and lateral views (for diaphyseal and distal humerus). Scapular Y-view can further characterize proximal humerus displacement.
   • Computed Tomography (CT) Scan: Indispensable for complex fractures, particularly intra-articular proximal (evaluating head-split, tuberosity comminution, articular congruity) and distal (delineating articular comminution, column involvement) humerus fractures. 3D reconstructions are highly valuable for understanding fracture morphology and planning reduction.
   • Magnetic Resonance Imaging (MRI): Less commonly indicated acutely, but may be useful to assess rotator cuff integrity (proximal humerus), brachial plexus injury (proximal/diaphyseal), or cartilage damage.
3. Fracture Classification: Utilize widely accepted classifications (e.g., Neer for proximal, AO/OTA for all segments) to guide treatment strategy and facilitate communication.
4. Templating: Use contralateral radiographs or known implant dimensions to template plate length, appropriate bend, and screw lengths. This aids in selecting appropriate hardware and anticipating potential challenges.
5. Hardware Selection:
   • Proximal Humerus: Locking plates (e.g., Philos, LPHP) are standard for ORIF. Reverse shoulder arthroplasty (rTSA) or hemiarthroplasty (HA) are options for unreconstructable fractures, especially in the elderly.
   • Diaphyseal Humerus: Intramedullary nails (IMN) (antegrade or retrograde) are often preferred for transverse/short oblique fractures and polytrauma. Plate osteosynthesis (locking or non-locking) is indicated for comminuted, segmental, or distal third fractures, or when IMN is contraindicated.
   • Distal Humerus: Dual plating (orthogonal or parallel) is the gold standard for displaced intra-articular fractures. Total elbow arthroplasty (TEA) may be considered in selected elderly patients with severe comminution and osteopenia.
6. Approach Planning: Pre-identify the surgical approach (deltopectoral, anterolateral, posterior, etc.), considering internervous planes, potential soft tissue issues, and access for reduction/fixation.
7. Anesthesia: General anesthesia is typical. Regional blocks (interscalene, supraclavicular for proximal/diaphyseal; axillary for distal) can provide excellent post-operative analgesia but may mask early signs of neurovascular compromise.

Patient Positioning

Optimizing patient positioning is crucial for adequate exposure, ease of reduction, and fluoroscopic access.

1. Proximal Humerus:
   • Beach Chair (Semi-sitting): Most common for deltopectoral approach. Head support, torso elevated to 30-60 degrees. Arm draped free to allow full range of motion. Permits easy fluoroscopic visualization in AP and lateral planes without repositioning the patient.
   • Supine: Alternative for some approaches. Arm should be supported on an arm table and draped free. Ensure adequate space for fluoroscopy.
2. Diaphyseal Humerus:
   • Supine: Standard for anterolateral, anterior, or deltopectoral approaches. Arm positioned on a radiolucent arm table or across the chest. Allows for easy fluoroscopy.
   • Lateral Decubitus: Preferred for posterior approach to the midshaft or distal shaft. Patient positioned with the injured arm superior, draped free over a bolster or arm board.
   • Beach Chair: Can be used for antegrade IMN insertion.
3. Distal Humerus:
   • Lateral Decubitus: Most common for posterior approaches. Patient positioned with the injured arm superior, supported on a padded arm rest (e.g., chest roll/axillary roll) or elevated arm table (e.g., cantilevered arm rest) to allow full elbow flexion/extension. Allows for easy visualization of the posterior aspect of the humerus.
   • Prone: Can also be used for posterior approaches, with the arm draped over a chest roll or supported on a specialized arm positioner.
   • Supine: Less common, typically for highly selected anterior approaches.

For all positions, ensure padding of pressure points, secure patient straps, and meticulous draping to allow sterile access and unrestricted fluoroscopic imaging.

Detailed Surgical Approach / Technique

The choice of surgical approach and technique is dictated by fracture morphology, location, associated injuries, and surgeon preference, all while adhering to established orthopedic principles.

Proximal Humerus: Locking Plate Osteosynthesis (e.g., LPHP)

Approach: Deltopectoral Approach
1. Incision: A longitudinal incision is made from the tip of the coracoid process distally towards the deltoid insertion.
2. Internervous Plane: The deltopectoral groove is identified between the deltoid muscle laterally (axillary nerve innervation) and the pectoralis major medially (medial and lateral pectoral nerve innervation). The cephalic vein typically lies within this groove and is retracted laterally with the deltoid, or medially with the pectoralis major.
3. Deep Dissection: The clavipectoral fascia is incised medial to the cephalic vein. The conjoint tendon (coracobrachialis and short head of biceps) and pectoralis major are retracted medially. The deltoid is gently retracted laterally.
4. Exposure: The subdeltoid space is entered. The anterior aspect of the humeral head and shaft, and parts of the greater and lesser tuberosities, are exposed. Care is taken to identify and protect the axillary nerve entering the posterior aspect of the deltoid approximately 5-7 cm distal to the acromion.
5. Reduction:
* Gentle traction is applied to the arm, often with ligamentotaxis.
* Fragment manipulation: Joy-stick K-wires can be inserted into the humeral head or tuberosity fragments to aid reduction.
* Use of periosteal elevators or blunt instruments to disimpact fragments.
* Restoration of the anatomical neck and articular surface alignment is paramount.
* Temporary K-wires (e.g., 2.0mm) can be used to hold reduced fragments (e.g., tuberosities to head, head to shaft).
6. Plate Application (e.g., LPHP):
* A specially contoured locking plate (e.g., Proximal Humeral Locking Plate) is selected.
* The plate is positioned laterally on the humerus, typically 5-8 mm distal to the superior aspect of the greater tuberosity, ensuring it does not impinge on the acromion or rotator cuff. The shaft of the plate should be centered on the humeral shaft.
* Proximal Fixation: Multi-directional locking screws are inserted into the humeral head. Aim for subchondral bone purchase but avoid intra-articular penetration. Fluoroscopy in multiple planes (AP, Y-view, axial) is crucial to verify screw position. Calcar support screws (oblique screws directed inferomedially) are critical for providing medial column stability, especially in osteoporotic bone.
* Shaft Fixation: Locking or non-locking cortical screws are inserted into the humeral shaft, providing stable diaphyseal purchase.
* Tuberosity Fixation: If tuberosities are comminuted or detached, sutures (non-absorbable) passed through the rotator cuff insertions and secured through suture holes in the plate (or around the shaft) can enhance tuberosity reduction and stability, reducing the risk of medial screw cutout.
7. Final Assessment: Check for stable fixation, anatomical reduction, full range of motion (shoulder), and absence of screw impingement or articular penetration via fluoroscopy.

Diaphyseal Humerus: IMN vs. Plate Osteosynthesis

Intramedullary Nailing (IMN)

• Indications: Transverse, short oblique, spiral fractures of the mid-diaphysis. Often preferred in polytrauma patients or for pathological fractures.
• Approach (Antegrade Nailing - Rotator Cuff Sparing):
  1. Positioning: Beach chair or supine with arm adducted.
  2. Incision: A 3-5 cm incision made just lateral to the acromion, extending distally.
  3. Entry Portal: A deltoid split is performed. The entry portal is created superior to the greater tuberosity, approximately 1-2 cm medial to the lateral edge of the tuberosity, or through the supraspinatus tendon. Careful retraction protects the rotator cuff. Ream the entry portal.
  4. Reaming: Progressive reaming of the intramedullary canal is performed to match nail diameter. Maintain reduction during reaming.
  5. Nail Insertion: The IMN is inserted gently. Reduce the fracture before or during nail advancement.
  6. Interlocking: Proximal and distal interlocking screws are inserted under fluoroscopic guidance. Ensure adequate cortical purchase.
  7. Pearls: Protect the radial nerve during distal interlocking, especially from drill bit or screw irritation. Check for nail distraction, which can impair healing.
• Approach (Retrograde Nailing - less common, risk to olecranon fossa):
  1. Positioning: Lateral decubitus or supine with elbow flexed.
  2. Incision: Posterior incision over the olecranon.
  3. Entry Portal: Trans-olecranon or supra-olecranon (through triceps tendon) entry point created just proximal to the olecranon fossa.
  4. Technique: Similar reaming and nailing principles as antegrade.
  5. Pearls: Risk of articular damage to the olecranon fossa and potential for olecranon stress fracture or pain.

Plate Osteosynthesis

• Indications: Long oblique, spiral, comminuted, segmental fractures, fractures with radial nerve palsy (for exploration), distal third fractures, or when IMN is contraindicated.
• Approach (Anterolateral):
  1. Incision: Longitudinal incision on the anterolateral aspect of the arm, starting distal to the deltoid insertion and extending distally as needed.
  2. Internervous Plane: Between the deltoid (proximally) and the biceps laterally, and the brachialis medially. Deep dissection often involves splitting the brachialis muscle.
  3. Radial Nerve: The radial nerve must be identified and protected. It typically crosses the humerus from medial to lateral in the spiral groove, approximately 10-14 cm proximal to the lateral epicondyle. Proximally, it lies posterior to the humerus. Distally, it pierces the lateral intermuscular septum to lie anteriorly. It is identified between the brachialis and brachioradialis muscles, medial to the lateral head of the triceps. The nerve is mobilized and retracted, usually posteriorly or laterally, using vessel loops.
  4. Reduction: Indirect reduction techniques (ligamentotaxis, plate as a reduction aid) are preferred to preserve periosteal blood supply. Direct reduction with clamps may be necessary for complex patterns.
  5. Plate Application:
     • Bridge Plating: For comminuted fractures, a locking plate is typically used as a bridge plate, spanning the comminution without directly fixing small fragments. Aim for 3-4 screws proximally and distally, ensuring adequate working length.
     • Compression Plating: For simple transverse or short oblique fractures, lag screws across the fracture followed by a neutralization plate, or dynamic compression plate (DCP) technique, can be employed.
     • Locking Plates: Provide angular stability, crucial in osteoporotic bone or comminuted fractures.
  6. Closure: Careful soft tissue closure, ensuring the radial nerve is not entrapped.

Distal Humerus: ORIF with Dual Plating

• Approach: Posterior Approach with Olecranon Osteotomy (Most common for complex intra-articular fractures)
  1. Positioning: Lateral decubitus or prone with arm supported to allow full elbow flexion.
  2. Incision: Posterior midline incision centered over the olecranon.
  3. Ulnar Nerve: Identify and mobilize the ulnar nerve from the cubital tunnel. It is typically transposed anteriorly or protected carefully during the entire procedure.
  4. Olecranon Osteotomy: A chevron or transverse osteotomy is performed across the olecranon. This provides wide, direct access to the articular surface of the distal humerus. The triceps mechanism is reflected proximally with the osteotomized olecranon.
  5. Exposure: The distal humerus articular surface and columns are fully exposed.
  6. Articular Reduction:
     • Meticulous anatomical reduction of the articular fragments (capitellum, trochlea). Temporary K-wires are crucial for holding these fragments.
     • The articular block is then reduced to the humeral shaft.
  7. Fixation: Dual Plating (Orthogonal or Parallel)
     • Orthogonal Plating: A plate is placed on the posterior aspect of the lateral column and another on the medial column (often 90 degrees to each other). Screws are interlocked between plates where possible.
     • Parallel Plating: Two plates are applied to the posterior aspect of the medial and lateral columns, maintaining a parallel configuration. This allows for longer screws and greater screw density.
     • Principles:
       • Secure fixation of the articular fragments to each other.
       • Stable fixation of the articular block to the humeral shaft.
       • Long bicortical screws are used whenever possible to maximize purchase.
       • Avoid intra-articular screw penetration (verified with fluoroscopy and direct visualization).
       • Plates should ideally span the fracture fragments and provide adequate working length.
  8. Olecranon Osteotomy Repair: The osteotomized olecranon is anatomically reduced and fixed using a tension band wiring technique (two parallel K-wires and an 18-gauge wire in a figure-of-eight fashion) or an olecranon plate.
  9. Final Assessment: Check for stable fixation, anatomical reduction, and full, pain-free range of elbow motion (if possible on table).

Complications & Management

Humerus fractures and their surgical management carry inherent risks. Proactive recognition and appropriate management of complications are vital.

General Complications (Across all Humerus Fractures)

• Infection:
  • Incidence: Varies from <1% in closed fractures to >10% in open fractures.
  • Management: Superficial infections: oral antibiotics. Deep infections: surgical debridement, tissue sampling for culture, intravenous antibiotics based on sensitivities. Hardware retention may be attempted if stable, otherwise removal and potentially re-fixation with external fixator or new internal fixation after infection control.
• Neurovascular Injury:
  • Incidence: Ranges from 5-18% for radial nerve (diaphyseal), 2-10% for axillary nerve (proximal), 1-5% for ulnar nerve (distal). Vascular injury is less common but more critical.
  • Management:
    • Neuropraxia: Observation, serial neurological exams, EMG studies at 3-6 weeks if no improvement. Most traumatic nerve palsies resolve spontaneously (e.g., radial nerve palsy with diaphyseal fracture).
    • Laceration/Traction: Surgical exploration is indicated for open fractures with nerve deficit, nerve deficits associated with vascular injury, or lack of neurological recovery after 3-6 months. Repair involves primary neurorrhaphy or nerve grafting.
    • Vascular: Immediate surgical exploration and vascular repair (e.g., primary anastomosis, vein grafting).
• Nonunion:
  • Incidence: 2-10% for diaphyseal, 5-20% for proximal (depending on fracture type and bone quality), 5-15% for distal.
  • Management: Revision surgery with stable fixation (plate osteosynthesis is often preferred for diaphyseal nonunions after IMN), bone grafting (autograft or allograft), and optimization of biomechanical environment. Bone stimulators may be adjunctively used.
• Malunion:
  • Incidence: Variable, depends on acceptable reduction criteria and fracture location.
  • Management: Observation if asymptomatic. Symptomatic malunion causing pain, decreased range of motion, or functional limitation may require corrective osteotomy.
• Hardware Failure/Prominence:
  • Incidence: Variable depending on implant and bone quality.
  • Management: Revision surgery with stronger hardware, bone grafting for nonunion, or hardware removal if asymptomatic and fracture is healed. Prominent hardware causing pain may require removal after fracture union.
• Complex Regional Pain Syndrome (CRPS):
  • Incidence: 1-5%.
  • Management: Early recognition, multidisciplinary approach including physical therapy, pain management (nerve blocks, medications), and psychological support.

Segment-Specific Complications

Proximal Humerus Specific

• Avascular Necrosis (AVN) of the Humeral Head:
  • Incidence: 0-13% for 2-part, 10-30% for 3-part, 15-70% for 4-part fractures. Higher with anatomical neck fractures.
  • Salvage: If symptomatic, Hemiarthroplasty (HA) or Reverse Total Shoulder Arthroplasty (rTSA) are options.
• Screw Cutout/Articular Penetration:
  • Incidence: 5-15%. Associated with osteoporotic bone and medial comminution.
  • Salvage: Early recognition (radiographs, CT). If acute and symptomatic, revision of screw placement or length. If severe joint damage, consideration for arthroplasty.
• Rotator Cuff Impingement/Tears:
  • Incidence: Variable, often associated with tuberosity malunion or hardware prominence.
  • Salvage: Arthroscopic débridement, rotator cuff repair, or hardware removal.
• Shoulder Stiffness/Loss of ROM:
  • Incidence: Common, up to 50% some degree.
  • Salvage: Intensive physical therapy, manipulation under anesthesia (MUA), arthroscopic capsular release.

Diaphyseal Humerus Specific

• Radial Nerve Palsy (Non-iatrogenic):
  • Incidence: 8-18%. Most are neuropraxias and recover spontaneously within 3-6 months.
  • Salvage: Observation for 3-6 months. Lack of recovery warrants exploration at 3-6 months (or earlier if open fracture, vascular injury, or nerve entrapment suspected). Tendon transfers if irreversible.
• Iatrogenic Radial Nerve Injury:
  • Incidence: <5% with plating. Up to 1-2% with IMN distal interlocking.
  • Salvage: Immediate exploration, nerve repair if transected.
• Distraction at Fracture Site (IMN):
  • Incidence: Can lead to nonunion.
  • Salvage: Dynamization of nail (if static prior), revision plating with compression, bone grafting.

Distal Humerus Specific

• Ulnar Nerve Neuropathy:
  • Incidence: 10-25% (pre- or post-operative).
  • Salvage: Observation for neuropraxia. Surgical exploration and neurolysis/transposition if persistent or progressive symptoms.
• Elbow Stiffness/Loss of ROM:
  • Incidence: Very common (up to 50% with >30° loss of flexion/extension arc).
  • Salvage: Aggressive physical therapy, dynamic splinting, manipulation under anesthesia (MUA), arthrolysis.
• Post-traumatic Arthritis:
  • Incidence: Variable, particularly with poor articular reduction or severe comminution.
  • Salvage: Conservative management initially. If severe and symptomatic, total elbow arthroplasty or arthrodesis in select cases.
• Heterotopic Ossification (HO):
  • Incidence: Up to 20% in severe trauma, head injury, or burns.
  • Salvage: Prophylaxis with NSAIDs or radiation therapy. Surgical excision if mature HO causes functional limitation.

Common Complications & Salvage Strategies

Post-Operative Rehabilitation Protocols

Post-operative rehabilitation is as critical as surgical execution for restoring function and preventing stiffness. Protocols are individualized based on fracture type, stability of fixation, bone quality, patient compliance, and associated injuries.

General Principles

• Pain Management: Adequate analgesia to facilitate early motion.
• Immobilization: Sling or brace for a prescribed period, usually to protect the repair and allow initial soft tissue healing.
• Early Motion: As soon as stability allows, controlled motion is initiated to prevent stiffness and promote cartilage health.
• Gradual Progression: Exercises progress from passive to active-assisted to active, and eventually to resisted strengthening.
• Therapist Involvement: Close collaboration with a physical/occupational therapist is crucial.
• Bone Healing: Radiographic evidence of healing guides progression, especially for weight-bearing and high-resistance activities.

Proximal Humerus (ORIF with Locking Plate)

• Phase 1: Protection (0-6 weeks)
  • Immobilization: Arm in a sling (e.g., UltraSling) continuously, removed only for exercises and hygiene.
  • Passive Range of Motion (PROM): Pendulum exercises, supine passive forward flexion (up to 90-120 degrees depending on stability), passive external rotation (0-30 degrees), internal rotation.
  • Hand/Wrist/Elbow: Active range of motion (AROM) to prevent stiffness.
  • Avoid: Active shoulder elevation, internal/external rotation, weight-bearing, lifting.
• Phase 2: Early Active Motion (6-12 weeks)
  • Sling: Gradually weaned as pain allows.
  • AROM: Progressive active and active-assisted ROM for shoulder flexion, abduction, and rotation.
  • Gentle Isometric Strengthening: Deltoid, rotator cuff (sub-maximal).
  • Scapular Stabilization: Exercises to improve scapulothoracic rhythm.
  • Avoid: Lifting heavy objects, sudden movements, excessive external rotation.
• Phase 3: Strengthening & Advanced Activities (12+ weeks)
  • Progressive Strengthening: With resistance bands, light weights. Focus on rotator cuff, deltoid, and periscapular muscles.
  • Proprioceptive Training:
  • Functional Activities: Gradual return to activities of daily living (ADLs) and light work.
  • Return to Sport: Highly individualized, typically 4-6 months, cleared by surgeon based on radiographic union and strength.

Diaphyseal Humerus (ORIF with Plate or IMN)

• Phase 1: Early Motion (0-2 weeks)
  • Immobilization: Sling for comfort, not necessarily for fracture stability unless specifically indicated.
  • AROM: Immediate active range of motion for elbow, wrist, and hand. Gentle passive shoulder ROM (pendulums, supine forward flexion) may be initiated immediately, depending on the fracture and fixation stability.
  • Avoid: Active shoulder abduction/external rotation if antegrade IMN (especially rotator cuff-splitting) was performed, or if proximal plate fixation is tenuous.
• Phase 2: Progressive Active Motion (2-6 weeks)
  • Sling: Weaned as comfort and stability allow.
  • AROM: Full active shoulder ROM, progressive elbow, wrist, hand AROM.
  • Gentle Isometric Strengthening: Start with shoulder and elbow isometrics.
• Phase 3: Strengthening & Functional Activities (6+ weeks)
  • Progressive Strengthening: With resistance bands, light weights. Focus on full upper extremity strength.
  • Functional Activities: Gradual return to ADLs, work, and sport.
  • Weight-Bearing: Restricted until radiographic evidence of union. Lifting restrictions typically maintained for 3-4 months.

Distal Humerus (ORIF with Dual Plating)

• Phase 1: Controlled Motion (0-2 weeks)
  • Immobilization: Posterior splint (often in 90 degrees flexion) for initial comfort and soft tissue healing, or sometimes a hinged elbow brace. Removed for exercises.
  • Early AROM/AAROM: Controlled active-assisted and active ROM of the elbow (flexion/extension, pronation/supination) started very early, often within a few days, as stability of fixation allows. Gravity-assisted movements.
  • Hand/Wrist/Shoulder: AROM to prevent stiffness.
  • Avoid: Heavy lifting, forceful active extension against gravity, stressing the repair.
• Phase 2: Progressive Motion & Light Strengthening (2-6 weeks)
  • Brace: Continued use of a hinged elbow brace, allowing gradual increase in ROM as tolerated.
  • AROM/AAROM: Progress towards full elbow flexion/extension and forearm rotation.
  • Gentle Isometric Strengthening: Forearm, biceps, triceps isometrics.
• Phase 3: Strengthening & Functional Activities (6+ weeks)
  • Progressive Strengthening: With resistance bands and light weights for all elbow and forearm musculature.
  • Functional Activities: Gradually introduce resistive activities.
  • Return to Sport/Work: Highly variable, often 4-6 months or longer, depending on the demands and fracture healing. Heterotopic ossification prophylaxis (NSAIDs or radiation) may be considered, especially in high-risk patients.

Summary of Key Literature / Guidelines

The management of humerus fractures has evolved significantly with advances in implant technology and a better understanding of fracture biology and biomechanics. Evidence-based guidelines inform current practice.

Proximal Humerus Fractures

• Non-Operative vs. Operative: The PROximal Fracture Of The Humerus (PROFHER) trial (2015) , a multicenter randomized controlled trial, found no significant difference in functional outcomes at 2 years between surgical fixation and non-operative treatment for displaced proximal humerus fractures in adults. This landmark study has shifted the paradigm towards a more conservative approach for many PHFs, particularly in older patients. However, its generalizability to all fracture types and patient populations (e.g., young, active patients, high-demand individuals, complex 4-part fracture-dislocations) remains debated.
• Surgical Options:
  • ORIF with Locking Plates: Considered the workhorse for many displaced PHFs, offering angular stability. The challenge lies in osteoporotic bone and the risk of AVN. Techniques like calcar screws and medial column support are emphasized to reduce hardware failure and improve outcomes.
  • Arthroplasty (HA or rTSA): Increasingly favored for unreconstructable 4-part fractures, particularly in elderly patients with poor bone quality. rTSA has demonstrated superior pain relief and functional outcomes (especially active elevation) compared to HA in many studies for complex PHFs in the elderly.
• AVN Risk: Factors associated with increased AVN include disruption of the medial calcar blood supply (e.g., true anatomical neck fractures), impaction of the head, and extensive devascularization of fragments in 3- and 4-part fractures.

Diaphyseal Humerus Fractures

• Non-Operative Management: A substantial portion (up to 90%) of diaphyseal humerus fractures can heal with non-operative treatment (e.g., functional brace, Sarmiento brace), achieving good functional outcomes despite some residual angulation.
• IMN vs. Plate Osteosynthesis:
  • Intramedullary Nailing: Advantages include minimal soft tissue stripping, load sharing, and potential for earlier rehabilitation. Risks include shoulder pain (with antegrade nails), elbow pain (with retrograde nails), and potential for radial nerve injury during distal interlocking. Meta-analyses suggest similar union rates but potentially higher rates of shoulder pain with antegrade IMNs compared to plating.
  • Plate Osteosynthesis: Offers direct visualization for reduction, strong fixation, and allows for radial nerve exploration if indicated. Risks include increased soft tissue dissection, infection, and reoperation rates compared to non-operative management.
  • Radial Nerve Palsy: While most traumatic radial nerve palsies resolve spontaneously, surgical exploration is typically warranted for open fractures, nerve deficits in conjunction with vascular injury, or failure of recovery after 3-6 months.

Distal Humerus Fractures

• ORIF is Gold Standard: Displaced intra-articular distal humerus fractures typically require open reduction and internal fixation (ORIF) to restore articular congruity and maintain stability for early motion.
• Dual Plating: The use of dual plates (orthogonal or parallel) provides robust biomechanical fixation, allowing early mobilization, which is crucial for elbow rehabilitation.
• TEA in Elderly: For highly comminuted, unreconstructable intra-articular fractures in elderly patients with low functional demands and poor bone quality, Total Elbow Arthroplasty (TEA) has emerged as a viable option, offering good pain relief and reliable functional outcomes, often with earlier mobilization.
• Ulnar Nerve Management: Ulnar nerve identification and transposition are frequently performed during posterior approaches to prevent iatrogenic injury and address pre-existing neuropathy.

In conclusion, the management of humerus fractures demands a comprehensive understanding of patient factors, fracture characteristics, surgical anatomy, biomechanics, and evidence-based literature. Treatment decisions are highly individualized, aiming to restore optimal function while minimizing complications and patient morbidity. Continuous advancements in surgical techniques and implant design necessitate ongoing education and adherence to best practices for orthopedic surgeons.