Proximal Humerus Fractures

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Fracture of the proximal humerus is a common injury often seen in older patients and one of the true osteoporotic fractures. PHF includes all fractures to the anatomical neck, surgical neck, greater tuberosity (GT), or lesser tuberosity, either isolated or in combination.

Clinically Relevant Anatomy

Osteology: Humerus

Classification: long bone

Features:

• Humeral head: The proximal articular surface of the upper extremity. It articulates with the glenoid fossa of the scapula.
• Greater tuberosity: Located lateral to the head at the proximal end.
• Lesser tuberosity: Located inferior to the head, on the anterior part of the humerus.
• Anatomic neck: Located between the head and the tuberosities.
• Surgical neck: Located between the tuberosities and the shaft.
• Intertubercular groove: a narrow groove between the greater tuberosity and the lesser tuberosity.
• Humeral shaft.

Function: serves as an attachment to 13 muscles which contribute to the movement of the hand and elbow, and therefore the function of the upper limb.

Muscles: The intrinsic muscles of the shoulder which connect the scapula and/or clavicle to the humerus include:

• Deltoid
• Teres major
• Supraspinatus
• Infraspinatus
• Teres minor
• Subscapularis
• Latissimus dorsi
• Pectoralis major
• Coracobrachialis
• Biceps brachii
• Triceps brachii
  

Mechanism of Injury / Pathological Process

Epidemiology

PHFs are the third most common fracture in the elderly, after proximal femur and distal radius fractures, and represent 10% of all fractures.

PHFs account for approximately 5.7% of fractures in adults, and increase in incidence with ageing and are one of the most common fractures among people aged over 65 years old.

In the US, about 370,000 ED visits due to humerus fractures, and PHFs were the most common, accounting for 50% of humerus fractures in 2008.

A study showed that overall age-standardised incidence rates for PHFs in men and women were 40.6 (95% CI 32.7, 48.5) and 73.2 (95% CI 62.2, 84.1) per 100,000 person-years, respectively, in South-Eastern Australia.

The mean age was 70 years old (16-97).

The risk of PHF increases with age and is most prevalent in osteoporotic elderly women. Apart from bone fragility, caused by osteopenia or osteoporosis, commonly reported risk factors include those related to increased risk of falls, such as low level of physical activity, impaired balance, or lower limb pain or injury.

Aetiology

The 2 most common mechanisms of PHF:

• High-level energy trauma (e.g., sports injuries and motor vehicle accidents)
• Low-energy trauma (e.g., a fall from a standing position or a direct blow to the shoulder)

Associated conditions

•Nerve injury: Common injuries are direct injuries to the brachial plexus or traction injuries to the axillary nerve. More likely in the presence of a fracture-dislocation.

•Vascular injury: Rare, but more likely in the presence of a fracture-dislocation. Higher likelihood in the elderly. Signs of distal ischaemia may be absent, but a large expanding haematoma, pulsatile external bleeding, unexplained hypotension, delayed anaemia and associated nerve trunk or plexus injury should increase the level of suspicion.

Clinical Presentation

Symptoms

Pain and swelling

Decreased motion

Classification

There are 2 main classifications used for PHF (Neer and AO/OTA classifications) and one specific to GT fractures.

The Neer Classification

The four-segment classification system describes PHFs by the number of displaced segments or parts, and additional categories for articular fracture and dislocation (Fig. 1). The GT, lesser tuberosity, articular surface, and humeral diaphysis are the potential segments involved. It is defined that the segment is displaced when there is greater than 1 cm separation or 45° angulation.

•One-Part fractures: No fragment satisfies the displacement criteria. Fractures without fragments considered displaced are defined as partial fractures, regardless of the actual number of fracture lines or their locations.

•Two-Part fractures: One segment is displaced, which is the GT, lesser tuberosity, or articular segment at the level of the anatomical neck or surgical neck.

•Three-Part fractures: One tuberosity is displaced, and surgical neck fracture is displaced. The remaining tuberosity is attached, and rotational deformation occurs.

•Four-Part fractures: All four segments (both tuberosities, articular surfaces, and shaft) satisfy the criteria for displacement. The articular segment is normally laterally displaced and out of contact with the glenoid (Figure 2). This is a serious injury and a high risk of avascular necrosis.

•Valgus-Impacted Four-Part Fractures: This pattern (Figure 2B) was added as a separate category in 2002. The head is rotated into a valgus position and pushed down between the tuberosities to accommodate the head. The articular surface remains in contact with the glenoid and is not laterally displaced.

•Fracture Dislocations and Articular Surface Injuries: Separate categories were added for dislocations, as they represent more severe injuries and are more likely to develop avascular necrosis and heterotopic ossification. Likewise, articular surface fractures fell into a separate category due to their unique management considerations. There are two types, which are head-splitting fractures and impaction fractures.

The AO/OTA Classification

The AO/OTA 2007 classification is based on the severity and articular/extraarticular and unifocal/bifocal pattern of the fracture, defining three main types (A, B, and C).

•Type A: extraarticular and unifocal

•Type B: extraarticular and bifocal

•Type C: articular

Diagnostic Procedures

Radiological assessment

•Plain x-rays: Plain radiographic imaging is the primary baseline investigation for diagnosis, classification, and management planning of PHFs. X-rays should include:

• A true anteroposterior view
• A Trans-scapular Y view
• An axillary lateral view

•Doppler ultrasound: May be used to assess the associated vascular injury and concomitant rotator cuff tears.

•Computerised tomography (CT): May be used to assess complex fracture patterns, while it also allows quantification of available bone stock and evaluation of the extent and location of fracture union.

•CT angiography: Can be used for accurate diagnosis and guiding management of co-existing arterial injury.

•Magnetic resonance arthrography: Additional imaging tool for the assessment of periarticular soft tissue.

•Angiography: Additional imaging tool for the assessment of vascular injuries.

Outcome Measures

•Constant-Murley score

•Disabilities of the Arm, Shoulder, and Hand score

•Visual Analogue Scale

•American Shoulder and Elbow Surgeons score

Management / Interventions

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Differential Diagnosis

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Resources

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