Proximal humerus fractures forms 4% to 5% of all fractures and represent the most common humerus fracture (45%), it’s more common in older individuals due to osteoporosis.
- Female > male (2:1).
- Mostly are nondisplaced (85%).
The most common mechanism of Proximal humerus fractures is a fall onto an outstretched upper extremity from a standing height, typically in an older woman (fragility fracture). Younger patients typically sustain a proximal humeral fracture following high-energy
trauma, such as a motor vehicle accident.
The shoulder has the greatest range of motion of any joint in the body, secondary to the shallow glenoid fossa that is only 25% the size of the humeral head. The major contributor to stability is not bone but the soft tissue envelope composed of muscle, capsule, and ligaments.
The proximal humerus is retroverted 35 to 40 degrees relative to the epicondylar axis.
The shoulder has four osseous segments (Neer):
- Humeral head
- Lesser tuberosity
- Greater tuberosity
- Humeral shaft
- The major blood supply is from the anterior and posterior humeral circumflex arteries.
- The arcuate artery is a continuation of the ascending branch of the anterior humeral circumflex. It enters the bicipital groove and supplies most of the humeral head. Small contributions to the humeral head blood supply arise from the posterior humeral circumflex, reaching the humeral head via tendo-osseous anastomoses through the rotator cuff.
- The axillary nerve courses just anteroinferior to the glenohumeral joint, traversing the quadrangular space. It is at particular risk for traction injury owing to its relative rigid fixation at the posterior cord and deltoid as well as its proximity to the inferior capsule where it is susceptible to injury during anterior dislocation and anterior fracturedislocation.
Fractures of the anatomic neck are uncommon, but they tend to have a poorer prognosis because of the precarious vascular supply to the humeral head.
Deforming muscular forces on the proximal humerus:
- The supraspinatus and external rotators: which displace the greater tuberosity superior and posterior.
- The subscapularis: which displaces the lesser tuberosity medially.
- The pectoralis major: which displaces the humeral shaft medially.
- The deltoid: which abducts the proximal fragment .
- Patients with Proximal humerus fractures typically present with the arm held closely to the chest by the contralateral hand, with shoulder pain, swelling, tenderness, painful range of motion, and variable crepitus.
- Ecchymosis about the proximal humerus may not be apparent immediately after injury. Chest wall and flank ecchymosis may be present and should be differentiated from thoracic injury.
- A careful neurovascular examination is essential, with particular attention to axillary nerve function. This may be assessed by the presence of sensation on the lateral aspect of the proximal arm overlying the deltoid.
- Motor testing is usually not possible at this stage secondary to pain.
Radiographic Evaluation of Proximal Humerus Fracture
Recommended Views in order to evaluate Proximal humerus fractures include:
- Anteroposterior AP View
- Lateral Y View.
- Axillary view.
- The axillary is the best view for evaluation of glenoid articular fractures and reduction of the glenohumeral articulation, but it may be difficult to obtain because of pain. This view does not accurately predict fracture angulation in the trauma setting.
- Velpeau axillary: If a standard axillary cannot be obtained because of pain or fear of fracture displacement, the patient may be left in the sling and leaned obliquely backward 45 degrees over the cassette. The beam is directed caudally, orthogonal to the cassette, resulting in an axillary view with magnification.
- Computed tomography is helpful in evaluating articular involvement, degree of fracture displacement, impression fractures, and glenoid rim fractures. It is also helpful when an axillary view is not obtainable.
- Magnetic resonance imaging is generally not indicated for proximal humerus fractures management, but it may be used to assess rotator cuff integrity.
Proximal Humerus Fracture Classification
Neer define 4 parts for proximal humeral:
- Articular surface
- Greater tuberosity
- Lesser tuberosity
- Humerus Shaft
He define the part as displacement of > 1 cm or angulation of > 45 degrees.
- One-part: nondisplaced or minimally displaced fracture (often of the humeral neck)
- Two-part: displacement of tuberosity of more than 1 cm; or surgical neck with head/shaft angled or displaced.
- Three-part: displacement of the greater or lesser tuberosities and articular surface
- Four-part: displacement of shaft, articular surface, and both tuberosities. “Head splitting” is a variant, with split through the articular surface (usually requires replacement for treatment).
Proximal Humerus Fracture treatment is based on the Neer classification and displacement of the parts:
Minimally displaced fractures (one-part fracture):
- Sling immobilization or swathe for comfort Early shoulder motion at 7 to 10 days consisting of pendulum exercises and passive range of motion.
- Early radiographic follow-up to detect loss of fracture reduction.
- Active range-of-motion exercises are started 6 weeks after injury.
- Resistive exercises are started anywhere from 6 to 12 weeks.
- Return to near full range of motion and function is the expected outcome by 1 year.
Anatomic neck fractures:
- Rare and difficult to treat by closed reduction. They require open reduction and internal fixation (ORIF) (younger patients) or prosthetic replacement (older individuals) and have been historically associated with a higher incidence of osteonecrosis.
Surgical neck fractures:
- Nonoperative treatment is rarely indicated except for angulated/displaced surgical neck fractures, which are stable (move as a unit) in lower demand individuals, severely debilitated patients, and those who cannot tolerate surgery.
- Closed reduction and percutaneously inserted terminally threaded pins or cannulated screws may be considered in younger individuals with good-quality bone.
Problems associated with multiple pin fixation include nerve injury (axillary), pin loosening, pin migration, and inability to move the arm.
- ORIF is the treatment of choice for most displaced surgical neck fractures of the proximal humerus and can involve placement of plate and screws or an intramedullary device. Most current proximal humerus plates use a locked screw construct for the metaphyseal component secondary to improved fixation of locked screws in osteopenic cancellous bone.
- Prosthetic replacement may be considered for patients with extreme osteopenia and involves use of hemiarthroplasty, total shoulder, or reverse shoulder prosthesis.
Greater tuberosity fractures:
- ORIF with or without rotator cuff repair is indicated for greater tuberosity fractures which are displaced >5 to 10 mm (5 mm for superior translation); otherwise, they may develop nonunion and subacromial impingement.
- A greater tuberosity fracture associated with anterior dislocation may reduce on reduction of the glenohumeral joint and be treated nonoperatively.
Lesser tuberosity fractures:
- They may be treated closed unless displaced fragment blocks internal rotation, one must rule out associated posterior dislocation.
- Usually unstable due to opposing muscle forces; as a result, closed reduction and maintenance of reduction are often difficult.
- Displaced fractures require operative treatment, except in severely debilitated patients or those who cannot tolerate surgery.
- Younger individuals should have an attempt at ORIF using plate and screws; preservation of the vascular supply is of paramount importance with minimization of soft tissue devascularization.
- Locking plate technology has expanded the indications for ORIF after three-part fracture in older individuals, secondary to improved screw fixation in osteopenic bone.
- However, one should be prepared to perform prosthetic replacement (hemiarthroplasty, total shoulder, or reverse shoulder prosthesis) in older individuals if necessary. There has been increased use of reverse shoulder prostheses as a prosthetic replacement after proximal humerus fractures in the elderly because of difficulty with tuberosity attachment and healing with conventional hemiarthroplasty.
- ORIF may be attempted in patients with good-quality bone if the humeral head is located within the glenoid fossa and there appears to be soft tissue continuity. Fixation is best achieved with locking plate and screw fixation, suture, and/or wire fixation.
- Primary prosthetic replacement of the humeral head (reverse shoulder prosthesis) is indicated in the elderly.
- Hemiarthroplasty is associated with predictable pain relief but with unpredictable results from the standpoint of function; has fallen out of favor in older individuals.
- Reverse total shoulder arthroplasty (rTSA) has demonstrated results similar to successful ORIF and better than hemiarthroplasty for fracture; has unique set of complications associated.
- Four-part valgus-impacted proximal humerus fractures represent variants that are associated with lower rate of osteonecrosis and have excellent results with ORIF.
Deltopectoral versus deltoid split:
- The deltopectoral approach is the workhorse of the shoulder and allows for an extensile approach to the proximal humerus. ORIF or arthroplasty of proximal humerus fracture is well performed through this approach.
- The deltoid split allows for easier plate placement on the greater tuberosity and requires fewer assistants to retract the deltoid muscle.
- Vascular injury: the axillary artery is the most common site (proximal to anterior circumflex artery).
- Neural injury: Brachial plexus injury, and axillary nerve injury.
- Chest injury: pneumothorax and hemothorax.
- Myositis ossificans/heterotopic ossification.
- Shoulder stiffness.
Questions & Answers for Patients:
How long does it take for a proximal humerus fracture to heal?
Proximal humerus fracture healing time depends on the type, severity of fracture and method of treatments. Usually it takes 6-8 weeks to heal, then patient should have a period of physical therapy in order to maintain shoulder joint range of motion and to strength muscles around the shoulder.