Proximal Humeral Fractures: Comprehensive Guide to Neer Classification, Anatomy & Diagnosis

Introduction & Epidemiology

Proximal humeral fractures (PHFs) represent a significant proportion of all fractures, accounting for approximately 5% of all adult fractures and a substantial burden, particularly in the geriatric population. Their incidence demonstrates a bimodal distribution, with high-energy trauma predominating in younger individuals and low-energy falls in osteoporotic elderly patients. The latter group, comprising the majority, presents unique challenges due to often comminuted fracture patterns and compromised bone quality.

The Neer classification system, introduced by Dr. Charles Neer in the 1970s, remains the most widely accepted and utilized system for categorizing PHFs. Despite its acknowledged limitations, particularly regarding inter-observer and intra-observer reliability, it serves as a foundational framework for communication, prognostication, and guiding treatment decisions among orthopedic surgeons. The classification is predicated on the anatomical relationship and displacement of four major segments, or "parts," of the proximal humerus:
1. Humeral Head (Articular Segment)
2. Greater Tuberosity
3. Lesser Tuberosity
4. Surgical Neck (Shaft Segment)

A "part" is defined as significantly displaced if it has separated from its anatomical position by greater than 1 cm or is angulated by more than 45 degrees . These displacement criteria are critical for accurate classification. Fractures failing to meet these displacement thresholds, regardless of the number of fracture lines, are considered "1-part" fractures.

The core Neer classification categorizes fractures as follows:
* 1-part fracture : Any fracture pattern where all fragments are displaced by less than 1 cm and angulated less than 45 degrees. This encompasses isolated fractures of the surgical neck, anatomic neck, greater tuberosity, or lesser tuberosity where displacement is minimal.
* 2-part fracture : One of the four major segments is displaced by greater than 1 cm or angulated by greater than 45 degrees relative to the remaining intact segment. Examples include:
* 2-part Surgical Neck : Most common type, where the humeral head-tuberosity complex is separated and displaced from the shaft.
* 2-part Anatomic Neck : Rare, involving a fracture directly through the articular cartilage attachment. High risk of avascular necrosis (AVN).
* 2-part Greater Tuberosity : Isolated fracture and displacement of the greater tuberosity, often resulting from a rotator cuff avulsion mechanism.
* 2-part Lesser Tuberosity : Isolated fracture and displacement of the lesser tuberosity, less common, typically associated with posterior dislocations or strong subscapularis contraction.
* 3-part fracture : Two of the four major segments are significantly displaced from each other and from the remaining primary segment. The most common patterns involve the surgical neck with displacement of one tuberosity.
* Surgical Neck and Greater Tuberosity : The articular segment remains attached to the lesser tuberosity, while the greater tuberosity and shaft are displaced.
* Surgical Neck and Lesser Tuberosity : The articular segment remains attached to the greater tuberosity, while the lesser tuberosity and shaft are displaced.
* 4-part fracture : All four major segments are significantly displaced from each other. This represents a complex and highly unstable fracture pattern.
* 4-part (Displaced) : All fragments are separated and significantly displaced, often leading to compromise of the humeral head's blood supply.
* 4-part Valgus-Impacted : A specific variant where the humeral head is impacted in a valgus position relative to the shaft. While technically meeting 4-part displacement criteria, the impaction often preserves the posteromedial blood supply, conferring a better prognosis for humeral head viability.
* Fracture-Dislocation : Any of the above fracture types combined with a dislocation of the humeral head from the glenoid. These can be anterior, posterior, or inferior.

The diagnostic imaging standard for PHFs includes orthogonal radiographs (true AP, scapular Y, and axillary views). However, computed tomography (CT) scans, particularly with 3D reconstructions, are often indispensable for accurately assessing comminution, articular involvement, tuberosity displacement, and guiding pre-operative planning, especially in complex 3- and 4-part fractures.

Surgical Anatomy & Biomechanics

A thorough understanding of the surgical anatomy and biomechanics of the proximal humerus is paramount for successful management of PHFs, particularly for preventing iatrogenic complications and optimizing fixation stability.

Surgical Anatomy

• Proximal Humerus Landmarks :
  • Humeral Head : Articulates with the glenoid fossa. Its blood supply is critical for viability.
  • Anatomic Neck : The groove delineating the articular cartilage from the tuberosities. Fractures here carry a high AVN risk.
  • Surgical Neck : The constricting region distal to the tuberosities, a common fracture site.
  • Greater Tuberosity (GT) : Lateral prominence, insertion site for supraspinatus, infraspinatus, and teres minor tendons (external rotators and abductor). Fractures here are typically displaced superiorly and posteriorly by rotator cuff pull.
  • Lesser Tuberosity (LT) : Medial prominence, insertion site for the subscapularis tendon (internal rotator). Fractures here are typically displaced anteriorly and medially.
  • Bicipital Groove : Separates the GT and LT, housing the long head of the biceps tendon.
• Blood Supply of the Humeral Head : This is the single most critical anatomical consideration determining the risk of AVN, especially in multi-part fractures.
  • The primary blood supply to the humeral head is derived from branches of the anterior circumflex humeral artery (ACHA) and posterior circumflex humeral artery (PCHA) .
  • The arcuate artery (ascending branch of the ACHA) , running in the bicipital groove, historically considered dominant, contributes significantly. However, recent evidence highlights the crucial role of the posteromedial ascending branch of the PCHA , which penetrates the metaphysis inferomedially.
  • The integrity of the periosteal sleeve and the soft tissue attachments to the humeral head fragment (especially the intact lesser tuberosity carrying the subscapularis and its vessels) directly influences head viability.
  • Displacement of the greater tuberosity (often avulsing the supraspinatus insertion) and the lesser tuberosity (subscapularis) significantly compromises this vascularity. The risk of AVN increases with the number of displaced fragments: highest in 4-part fractures, particularly those without valgus impaction.
• Neurological Structures at Risk :
  • Axillary Nerve : Most frequently injured nerve. It wraps around the surgical neck, passing through the quadrangular space inferior to the glenohumeral joint capsule, approximately 5-7 cm distal to the acromial edge. It innervates the deltoid and teres minor, providing sensory innervation over the lateral shoulder (regimental badge area). Vulnerable during both open and percutaneous approaches, especially with excessive retraction or screw placement.
  • Musculocutaneous Nerve : Less commonly injured, courses through the coracobrachialis.
  • Radial Nerve : Although more distal, it can be at risk in extensive distal dissection or with traction.
  • Brachial Plexus : Can be injured with high-energy trauma or severe fracture-dislocations.

Biomechanics

• Rotator Cuff Influence : The rotator cuff muscles exert significant forces on the proximal humerus, directly influencing fragment displacement and fracture stability.
  • Supraspinatus, Infraspinatus, Teres Minor : Insert on the greater tuberosity. Their combined pull typically displaces the GT fragment superiorly and posteriorly.
  • Subscapularis : Inserts on the lesser tuberosity. Its pull displaces the LT fragment anteriorly and medially.
  • Deltoid : Originates from the acromion and clavicle, inserts on the deltoid tuberosity. Its pull can cause superior displacement of the humeral shaft, especially in surgical neck fractures.
• Fracture Stability : The stability of a PHF is dictated by the fracture pattern, comminution, bone quality, and the integrity of the soft tissue sleeve.
  • Medial Calcar : The medial cortical buttress provides critical support against varus collapse, particularly important in surgical neck fractures. Loss of this support is a predictor of fixation failure.
  • Bone Quality : Osteoporotic bone significantly compromises screw purchase and overall fixation stability, increasing the risk of cut-out or pull-out.
• Deforming Forces : Understanding the deforming forces is crucial for successful reduction. For instance, in a 2-part surgical neck fracture, the deltoid pulls the shaft proximally, while the rotator cuff muscles can exert torsional forces on the head fragment. In tuberosity fractures, the specific rotator cuff muscle attached to the fragment will dictate its displacement.

Indications & Contraindications

Treatment decisions for PHFs are complex and multifactorial, integrating the Neer classification, patient demographics, activity level, bone quality, surgeon experience, and shared decision-making. The goal is to achieve a stable, well-aligned union while preserving function and minimizing complications.

Non-Operative Indications

Non-operative management, typically involving a sling for comfort and early controlled rehabilitation, is the preferred approach for a significant proportion of PHFs.
* 1-part fractures : By definition, these fractures exhibit minimal displacement and angulation (less than 1 cm displacement and less than 45 degrees angulation) and are inherently stable. They are almost universally treated non-operatively.
* Minimally displaced 2-part fractures : Even if technically meeting the Neer criteria for 2-part, if displacement/angulation is borderline or deemed clinically insignificant, non-operative management may be appropriate.
* Specific fracture types :
* Impacted valgus surgical neck fractures, particularly in elderly patients, where stability is inherently greater.
* Isolated, minimally displaced greater tuberosity fractures without significant impingement risk.
* Patient factors :
* Elderly, low-demand patients with significant comorbidities where the risks of surgery outweigh the potential benefits of improved anatomical reduction.
* Non-ambulatory or neurologically impaired patients where shoulder function is not a primary concern.

Operative Indications

Surgical intervention aims to restore anatomical alignment, provide stable fixation, facilitate early motion, and minimize the risk of complications such as malunion, nonunion, or AVN. The choice of surgical technique (ORIF, IMN, hemiarthroplasty, reverse total shoulder arthroplasty) depends on the fracture pattern, patient age, bone quality, and integrity of the rotator cuff.

• Displaced 2-part surgical neck fractures :
  • Significant angulation (>45 degrees) or displacement (>1 cm) in younger, active patients.
  • Unstable patterns (e.g., highly comminuted surgical neck, reverse obliquity).
  • Open fractures.
• Displaced 2-part greater tuberosity fractures :
  • Displacement >0.5 cm to 1 cm (controversial threshold, but often treated if >0.5 cm in young patients to avoid impingement and rotator cuff dysfunction).
  • Fractures causing significant impingement with arm abduction.
• Displaced 2-part lesser tuberosity fractures :
  • Often associated with posterior dislocations. Displacement can lead to subscapularis dysfunction and internal rotation contracture.
  • Rarely isolated, but if significantly displaced and causing functional deficit, may warrant repair.
• Displaced 3-part fractures :
  • Generally considered unstable due to significant displacement of two fragments relative to the third, often warranting ORIF.
  • Especially in younger, active patients.
• Displaced 4-part fractures :
  • In younger, active patients, attempts at ORIF may be considered if the blood supply to the head is deemed salvageable (e.g., valgus-impacted 4-part).
  • In elderly patients with poor bone quality and high AVN risk, primary arthroplasty (hemiarthroplasty or reverse total shoulder arthroplasty) is often the preferred option.
• Fracture-dislocations :
  • Require prompt reduction of the dislocation followed by management of the fracture pattern.
  • Persistent instability or inability to achieve closed reduction often necessitates open reduction and internal fixation or arthroplasty.
• Open fractures : Always require surgical debridement, irrigation, and stabilization.
• Neurovascular compromise : Requires emergent surgical exploration and repair/decompression.
• Failed non-operative management : Persistent pain, increasing displacement, or nonunion.

Contraindications (Relative)

• Severe medical comorbidities : Patients unable to tolerate anesthesia and surgery.
• Active infection : Local or systemic infection.
• Extremely poor bone quality : Where stable fixation is unlikely to be achieved, potentially leading to immediate failure.
• Non-reconstructable articular surface : Extensive comminution of the humeral head, making anatomical reduction impossible (often an indication for arthroplasty rather than a contraindication to surgery per se).
• Prior existing shoulder pathology : Severe glenohumeral arthritis or irreparable rotator cuff tears may influence the choice towards arthroplasty.

Summary of Operative vs. Non-Operative Indications

Pre-Operative Planning & Patient Positioning

Meticulous pre-operative planning is crucial for optimizing outcomes and mitigating complications in PHF surgery. This involves comprehensive patient assessment, detailed imaging analysis, and a tailored surgical strategy.

Pre-Operative Planning

• Patient Assessment :
  • Thorough medical history and physical examination, including assessment of comorbidities (e.g., diabetes, osteoporosis, cardiovascular disease, coagulopathies).
  • Neurological and vascular assessment of the upper extremity, documenting any pre-existing deficits.
  • Evaluation of patient's functional demands, hand dominance, and activity level.
  • Discussion of treatment options, potential outcomes, and complications with the patient and family.
• Imaging Review :
  • Plain Radiographs : Standard true AP, scapular Y, and axillary views are essential for initial diagnosis and classification. Evaluate fracture pattern, displacement, angulation, and bone quality.
  • Computed Tomography (CT) Scan : Indispensable for complex fractures (3- and 4-part, fracture-dislocations, articular involvement, comminution, tuberosity displacement). 3D reconstructions are highly valuable for understanding spatial relationships of fragments and planning reduction. Look for impaction, head-split components, and glenoid involvement.
  • Magnetic Resonance Imaging (MRI) : Rarely needed acutely, but can be useful for assessing rotator cuff integrity or soft tissue injuries in specific cases, particularly if considering a repair in a chronic setting.
• Implant Selection : The choice of implant is dictated by fracture morphology, bone quality, patient age, and surgeon preference.
  • Plate and Screw Fixation (ORIF) : Most common for 2- and 3-part fractures, and selected 4-part fractures (especially valgus-impacted) in younger patients. Modern locking plates (e.g., PHILOS plate) offer angular stability, crucial in osteoporotic bone. Consider plate length, screw configuration (calcar screws, divergent head screws), and suture eyelets for tuberosity reattachment.
  • Intramedullary Nailing (IMN) : Less common for complex fractures, primarily used for stable 2-part surgical neck fractures, particularly in younger patients. Offers less soft tissue disruption but can be challenging with tuberosity control.
  • Arthroplasty :
    • Hemiarthroplasty (HA) : Traditionally used for displaced 3- and 4-part fractures, particularly in elderly patients with high AVN risk or extensive comminution, when rotator cuff function is expected to be good. Requires meticulous tuberosity repair for good outcomes.
    • Reverse Total Shoulder Arthroplasty (rTSA) : Increasingly favored for complex 3- and 4-part fractures in older patients (typically >70-75 years old), especially with compromised rotator cuff function or poor bone quality. Offers more predictable functional outcomes compared to HA in this demographic.
• Surgical Strategy :
  • Approach : Deltopectoral is the workhorse for most ORIF and arthroplasty cases. Anterolateral/deltoid-splitting can be used for IMN or specific indications.
  • Reduction Sequence : Develop a systematic plan for fragment reduction (e.g., tuberosities to head, then head/tuberosity complex to shaft).
  • Temporary Fixation : K-wires are invaluable for provisional stabilization.
  • Definitive Fixation : Plan screw trajectories, plate placement, and suture passages.
  • Bone Graft : Consider autograft or allograft for comminuted fractures or cases with expected nonunion (e.g., medial calcar bone loss).

Patient Positioning

• Operating Table : Radiolucent table is essential for unrestricted intraoperative fluoroscopy.
• Positioning :
  • Beach Chair Position : Most common for PHF surgery. Allows for easier access to the shoulder, gravity-assisted reduction, and good visualization.
    • Patient is semi-recumbent, with the torso elevated (typically 30-45 degrees).
    • Head is secured in a headrest, carefully avoiding excessive cervical extension.
    • The affected arm is free-draped, allowing for full range of motion.
    • The opposite arm is tucked at the side.
    • Pillows support the lumbar spine and knees.
    • Care must be taken to prevent brachial plexus stretching, ulnar nerve compression (contralateral arm), and excessive head rotation/flexion.
  • Supine Position : Less common, but preferred by some surgeons, especially if a traction table is to be used or for very large patients. Offers stability for long cases.
    • Patient supine on a radiolucent table.
    • Affected arm draped free or placed on an arm board/traction tower.
    • Consideration for a small bump under the ipsilateral scapula to protract the shoulder.
• Fluoroscopy Setup : Ensure the C-arm can obtain true AP, scapular Y, and axillary views without repositioning the patient or breaking sterility. The C-arm should be positioned on the opposite side of the surgical field to avoid obstruction.
• Sterile Prep and Drape : Standard shoulder prep (chin to iliac crest, circumferentially to mid-humerus). Four-corner draping technique with a sterile stockinette or impervious adhesive drape for the arm.

Detailed Surgical Approach / Technique

This section will primarily detail the deltopectoral approach for open reduction and internal fixation (ORIF) with a locking plate, as it is the most common technique for displaced 2- and 3-part fractures, and selected 4-part fractures, aiming for humeral head salvage. Arthroplasty techniques, while critical, are beyond the scope of a "mastering Neer classification" focused on fracture patterns.

Deltopectoral Approach for ORIF with Locking Plate

The deltopectoral approach offers excellent exposure of the proximal humerus, making it suitable for complex PHFs requiring anatomical reduction and stable fixation.

1. Incision : A curvilinear incision is made from the coracoid process, extending distally along the deltopectoral groove for approximately 8-12 cm, depending on patient size and comminution.
2. Internervous Plane : The approach utilizes the internervous plane between the deltoid muscle (innervated by the axillary nerve, arising from the posterior cord) laterally and the pectoralis major muscle (innervated by the medial and lateral pectoral nerves) medially.
3. Superficial Dissection :
   • Identify the cephalic vein within the deltopectoral groove. It typically lies superficially. It is generally retracted medially with the pectoralis major, but can be ligated if necessary for improved exposure, though this risks post-operative edema.
   • Incise the clavipectoral fascia just lateral to the cephalic vein. This opens into the subdeltoid space.
4. Deep Dissection & Exposure :
   • Retract the deltoid laterally and the pectoralis major medially.
   • Carefully identify and protect the axillary nerve . This nerve courses inferolaterally, approximately 5-7 cm distal to the acromion, wrapping around the surgical neck. During retraction, ensure adequate inferior protection of the axillary nerve, especially if using a self-retaining retractor.
   • The long head of the biceps tendon is identified in its groove, serving as a key anatomical landmark for orienting the plate. It can be a deforming force in fracture patterns involving the bicipital groove.
   • Identify the rotator interval (between supraspinatus and subscapularis). This can be opened for further exposure of the humeral head and glenoid, particularly in fracture-dislocations.
   • The subscapularis tendon (inserting on the lesser tuberosity) is visualized. If necessary for adequate exposure or reduction, a partial or full tenotomy/release of the subscapularis can be performed, carefully protecting the anterior circumflex humeral vessels that often lie on its deep surface. This should be repaired meticulously at closure.
5. Reduction of Fracture Fragments : This is often the most challenging part of the procedure, requiring patience and anatomical understanding.
   • Indirect Reduction : Initial traction and external manipulation of the arm can help restore gross alignment.
   • Head Reduction : The humeral head fragment is often rotated or impacted. Gentle manipulation with blunt instruments (e.g., elevators, bone hooks) can disimpact and rotate the head. A K-wire inserted into the head can serve as a "joystick" for controlled manipulation.
   • Tuberosity Reduction :
     • Greater Tuberosity : Often displaced superiorly and posteriorly by the supraspinatus. Sutures (non-absorbable, braided) are placed through the rotator cuff insertions (supraspinatus, infraspinatus, teres minor) on the GT fragment. These sutures are then used to pull the GT inferiorly and anteriorly back to its anatomical position.
     • Lesser Tuberosity : Often displaced anteriorly and medially by the subscapularis. Sutures are placed through the subscapularis insertion for reduction.
   • Shaft-Head Realignment : Once the head and tuberosities are anatomically reduced, the shaft is brought into alignment. Traction and gentle rotation are often required.
   • Temporary Fixation : K-wires are critical for maintaining reduction. Typically, 2-3 K-wires are used to stabilize the head to the shaft and the tuberosities to the head. Ensure K-wires are not in the path of planned screw trajectories.
6. Fixation with Locking Plate :
   • Plate Selection and Contouring : Select a pre-contoured locking plate (e.g., PHILOS, Stryker VariAx). The plate should be placed laterally on the humerus, distal to the greater tuberosity, and oriented parallel to the bicipital groove. Avoid positioning the plate too proximally (risk of impingement) or too anteriorly.
   • Initial Plate Placement : Secure the plate to the humeral shaft with a single non-locking cortical screw to allow for minor adjustments. Confirm plate position and reduction under fluoroscopy (true AP, Y, and axillary views).
   • Medial Column Support : Critical for preventing varus collapse. A calcar screw, which engages the medial cortex of the humeral head, is paramount. Aim for at least one or two bicortical calcar screws if possible, or ensure strong support from divergent locking screws in the inferior portion of the head fragment. Autologous bone graft (e.g., from the greater tuberosity in a 4-part fracture) can be placed in the medial void to buttress the calcar.
   • Humeral Head Screw Placement : Insert multiple locking screws (typically 5-7) into the humeral head fragment. These screws should be divergent, aiming to capture maximum bone stock and support the articular surface. Ensure screws do not penetrate the articular surface (check fluoroscopically in multiple views, and perform direct visualization if possible).
   • Shaft Screw Placement : Insert 2-3 bicortical locking screws into the humeral shaft for distal fixation.
   • Tuberosity Reattachment : Pass the previously placed rotator cuff sutures through the suture eyelets on the plate. Tie these sutures securely to pull the tuberosities firmly against the humeral head and plate, ensuring anatomical reconstruction of the rotator cuff footprint. Additional non-absorbable sutures can be passed through bone tunnels or around the shaft for added tuberosity security.
7. Final Checks :
   • Fluoroscopy : Reconfirm anatomical reduction, plate position, and screw lengths in all planes. Check for articular penetration.
   • Stability : Assess stability of fixation by gently ranging the shoulder.
   • Soft Tissue Coverage : Ensure adequate soft tissue coverage over the plate.
   • Hemostasis : Achieve meticulous hemostasis. A drain may be considered.
8. Closure : Layered closure of the deltopectoral fascia, subcutaneous tissue, and skin.

Specific Considerations for Neer Types

• 2-part Surgical Neck : ORIF with plate and screws is common. IMN can be an option if tuberosities are intact.
• 2-part Greater Tuberosity : Often treated with suture repair (via bone tunnels or anchors), or screw fixation for larger fragments. Plate fixation may be used for comminuted GT fractures.
• 3-part Fractures : Require meticulous reduction of the tuberosities to the head, then the entire head-tuberosity complex to the shaft. Locking plates with multiple head screws and strong tuberosity sutures are essential.
• 4-part Fractures :
  • ORIF : Extremely challenging due to comminution and high AVN risk. Best reserved for younger patients, valgus-impacted patterns, or surgeons with significant experience. Meticulous soft tissue handling to preserve any remaining blood supply is paramount.
  • Arthroplasty : Hemiarthroplasty or rTSA are often preferred in elderly patients due to more predictable outcomes and lower AVN risk, particularly if rotator cuff function is compromised. This involves replacing the humeral head and meticulously repairing the tuberosities around the prosthesis.

Complications & Management

Despite advancements in surgical techniques and implants, PHFs, especially complex patterns, are associated with a notable rate of complications. Proactive recognition and appropriate management are essential.

Post-Operative Rehabilitation Protocols

Post-operative rehabilitation is as critical as the surgical procedure itself for achieving optimal functional outcomes following PHF fixation. Protocols must be individualized, considering the fracture pattern, stability of fixation, bone quality, type of surgery, patient age, and activity level. The overarching goals are to protect the repair, manage pain and swelling, restore range of motion (ROM), and progressively regain strength and function.

General Principles

• Protection : The primary concern in the early phase is to protect the surgical repair from excessive forces that could lead to fixation failure, nonunion, or loss of reduction.
• Early Motion : Within protected ranges, early passive and active-assisted motion is encouraged to prevent stiffness and promote articular cartilage health.
• Gradual Progression : Rehabilitation is typically phased, with a progressive increase in intensity and range of motion over several months.
• Pain Management : Effective pain control is vital to facilitate participation in physical therapy.

Phases of Rehabilitation (General Guidelines)

Phase 1: Immobilization and Passive Motion (0-6 weeks Post-Op)

• Goal : Protect healing fracture, reduce pain and inflammation, initiate passive range of motion.
• Immobilization : Arm maintained in a sling (or abduction pillow sling, depending on surgeon preference and fracture pattern) for 4-6 weeks, removing only for exercises and hygiene. Avoid active shoulder motion.
• Exercises (Daily) :
  • Pendulum Exercises : Performed several times daily, allowing gravity to gently distract the joint.
  • Passive Range of Motion (PROM) : Performed by a therapist or with the uninvolved hand.
    • Forward Flexion : Up to 90 degrees initially, progressing as tolerated.
    • External Rotation : Up to 0-30 degrees (shoulder in adduction), protecting tuberosity repair. Avoid internal rotation beyond neutral.
    • Scapular Mobilization : Gentle passive movements to maintain scapular rhythm.
  • Elbow, Wrist, Hand AROM : Maintain distal extremity mobility.
  • Pain & Edema Management : Ice, NSAIDs, elevation.
• Restrictions : No active shoulder motion, no lifting, no supporting body weight with the affected arm. Avoid active external/internal rotation against resistance, especially with tuberosity repair.

Phase 2: Active-Assistive and Early Active Motion (6-12 weeks Post-Op)

• Goal : Gradually restore active range of motion, begin gentle strengthening. Fracture healing should be evident on radiographs.
• Sling Use : Discontinue sling use as pain allows and fracture stability is confirmed.
• Exercises :
  • Active-Assistive Range of Motion (AAROM) : Progress from PROM to AAROM for forward flexion, abduction, and rotation.
  • Active Range of Motion (AROM) : Gradually initiate unassisted active motion as tolerated and guided by the therapist.
  • Gentle Isometrics : Begin with submaximal isometric contractions for rotator cuff and deltoid, with arm in protected positions.
  • Scapular Stabilization Exercises : Focus on periscapular muscle strength and control.
• Restrictions : No lifting objects heavier than a coffee cup. Avoid sudden or forceful movements. Continue to avoid activities that put direct stress on the fracture site.

Phase 3: Progressive Strengthening (12-24 weeks Post-Op)

• Goal : Achieve full active range of motion, progressively increase strength and endurance, improve proprioception.
• Exercises :
  • Progressive Resistance Exercises (PREs) :
    • Rotator Cuff Strengthening : Using resistance bands (therabands) or light weights for internal/external rotation, scapular plane elevation.
    • Deltoid Strengthening : Light weights for flexion and abduction.
    • Biceps/Triceps Strengthening : As tolerated.
  • Endurance Training : Light functional activities.
  • Neuromuscular Re-education : Proprioceptive exercises.
• Restrictions : Gradually lift heavier objects as strength improves. Avoid heavy overhead lifting until significant strength is restored.

Phase 4: Return to Activity / Advanced Strengthening (4-6+ months Post-Op)

• Goal : Return to desired work, recreational, and sport-specific activities. Achieve maximal strength and functional independence.
• Exercises :
  • Advanced Strengthening : Continue with PREs, gradually increasing resistance, incorporating plyometrics or sport-specific training.
  • Functional Training : Mimic specific activities required for work or sport.
• Return to Sport/Work : Guided by physician and therapist, based on strength, pain, and functional assessment. Full return to strenuous overhead activities or contact sports may take 6-12 months or longer, and may not always be fully achieved, particularly in complex fractures.

Special Considerations for Specific Surgical Interventions

• Tuberosity Fractures : Greater caution with external rotation and abduction in the early phases (for GT repair) and internal rotation (for LT repair) to protect the healing rotator cuff.
• Arthroplasty (Hemi or Reverse TSA) : Specific protocols exist.
  • Hemiarthroplasty : Emphasis on meticulous rotator cuff repair and protection during early rehab, similar to ORIF with tuberosity repair.
  • Reverse TSA : Often allows for earlier active elevation (deltoid driven), but with specific precautions regarding shoulder extension and adduction (to prevent dislocation) and protection of any residual rotator cuff repair.

Summary of Key Literature / Guidelines

The management of PHFs, guided by the Neer classification, has evolved significantly, with ongoing debate and research refining treatment strategies.

• Historical Context and Limitations of Neer Classification : Neer's original work provided a crucial framework, but its inherent subjectivity has been a long-standing concern. Studies consistently demonstrate moderate to poor inter-observer reliability, particularly for 3- and 4-part fractures, making consistent application challenging. This limitation underscores the need for high-quality imaging (CT scans) and surgeon experience. Newer classification systems (e.g., AO/OTA) have attempted to improve reliability but have not supplanted Neer in common clinical use for PHFs.
• Evolution of Treatment Paradigms :
  • Non-Operative Management : Remains the cornerstone for 1-part and minimally displaced fractures. Outcomes are generally good, with a high union rate. However, long-term stiffness and residual pain can occur.
  • Open Reduction Internal Fixation (ORIF) : With the advent of locking plate technology (e.g., PHILOS plate), ORIF became the dominant surgical choice for displaced 2- and 3-part fractures. Locking plates provide angular stability, improving construct stiffness, especially in osteoporotic bone, and reducing screw pull-out. Studies generally support good functional outcomes for 2- and 3-part fractures treated with ORIF in appropriate patients. However, complications like AVN (especially in 3- and 4-part), screw cut-out, and stiffness remain concerns.
  • Intramedullary Nailing (IMN) : While attractive for less soft tissue stripping, IMN has generally shown mixed results for PHFs, primarily limited to stable 2-part surgical neck fractures. Challenges include difficulty controlling rotation and tuberosity reduction, and potential for impingement from prominent hardware.
  • Arthroplasty : The role of primary arthroplasty has expanded significantly, particularly for complex 3- and 4-part fractures in the elderly.
    • Hemiarthroplasty (HA) : Traditionally indicated for comminuted 3- and 4-part fractures where the humeral head is deemed unsalvageable or at high risk of AVN. Success is highly dependent on meticulous tuberosity repair and healing, which can be inconsistent, leading to variable functional outcomes, particularly for active elevation.
    • Reverse Total Shoulder Arthroplasty (rTSA) : Has emerged as a robust option for comminuted 3- and 4-part PHFs in older patients (>70-75 years), especially those with pre-existing rotator cuff deficiency or poor bone quality where tuberosity healing is unreliable. Literature increasingly supports superior functional outcomes (especially active elevation) for rTSA compared to HA in this population, by bypassing the need for a functional rotator cuff.
• Key Clinical Trials and Evidence :
  • The PROximal humerus FRAgment (PROFIT) trial (2015) , a landmark multicenter randomized controlled trial, investigated surgical vs. non-surgical treatment for displaced PHFs in adults. It primarily focused on Neer 2-part surgical neck fractures. The study concluded that surgical intervention (ORIF) did not result in a significantly better outcome at 2 years compared to non-operative treatment, particularly in older patients. This Level I evidence prompted a re-evaluation of aggressive surgical management for certain displaced fractures, advocating for careful patient selection and shared decision-making. However, it's crucial to note PROFIT did not address 3- or 4-part fractures or fracture-dislocations.
  • Subsequent meta-analyses and systematic reviews continue to highlight the heterogeneity of PHF outcomes and the need for individualized treatment. For 3- and 4-part fractures, particularly in the elderly, arthroplasty (increasingly rTSA) is often favored over ORIF due to high AVN rates and functional limitations after ORIF.
• Current Guidelines and Trends :
  • There is no single universally accepted algorithm, but a consensus favors a patient-centered approach.
  • 1-part fractures : Non-operative treatment.
  • 2-part surgical neck fractures : Consider PROFIT trial implications, especially in older patients. ORIF for younger, active patients with significant displacement/angulation.
  • 2-part greater tuberosity fractures : ORIF if >5-10mm displacement in active individuals.
  • 3-part fractures : ORIF remains a viable option in good bone quality and younger patients. Arthroplasty is increasingly considered in older patients.
  • 4-part fractures : Primary arthroplasty (rTSA for elderly with concerns about rotator cuff/bone quality; HA for younger elderly with good cuff) is often preferred due to high AVN risk with ORIF. ORIF is reserved for specific cases (younger patients, valgus-impacted, excellent bone quality).
  • Valgus-impacted 4-part fractures : Often have a better prognosis for head viability with ORIF than other 4-part patterns, making ORIF a more attractive option.
  • Ongoing research continues to investigate biological augmentation, optimal implant designs, and patient-specific factors to further refine treatment strategies and improve outcomes for this challenging fracture population.