Proximal Humerus Fractures: Neer Classification, Anatomy, Imaging and Treatment

• Proximal humerus fractures are common accounting 5% of all adult fractures
• These fractures mostly occur in elderly patients, especially patients who are osteoporotic (e.g. postmenopausal women), after low energy falls
• There is options for operative and non operative treatment for these fractures and deciding between them can be very difficult

Anatomy of proximal humerus

• Proximal humerus consist of four major parts, they include:
  • Anatomical head
  • Greater tuberosity
  • Lesser tuberosity
  • Shaft

• The anatomical head articulate with the glenoid cavity of the scapula 
• Humeral head is directed predominantly medially, and oriented superiorly by 130 degrees and anteriorly by 30 degree
• The anatomical neck of the humerus is formed by a groove around the anatomical head and it separates the head from the tuberosities
• Anatomical neck is the line of attachment of the glenohumeral joint capsule

• The greater tuberosity is at the lateral aspect of the humeral head, it is the site of the insertion of three of the rotator cuff muscles: supraspinatus, infraspinatus and teres minor
• The lesser tuberosity is placed more anteriorly and it is the site of insertion for the subscapularis muscle
• Greater and lesser tuberosities are separated by the intertubercular sulcus (bicipital groove) 
• When a tuberosity fractures and gets displaced, the attached muscles loss their function and this is equivalent to a rotator cuff tear
• The anatomical head and tuberosities make up the surgical head of the humerus
• The surgical neck of the humerus lies at the junction of the surgical head and the shaft
• Surgical neck is a common site of fractures

Nerves and vessels

• Brachial plexus and axillary artery both run together medial to the coracoid process of the scapula and medial to the conjoint tendon (coracobrachialis + short head of biceps) into the arm
• Both could be injured in proximal humerus fractures

Mechanism of injury

• Proximal humerus fractures usually caused by a fall on the outstretched arm or a fall on the shoulder in elderly patients or associated with a high energy trauma in younger patients
• Same mechanism might cause a shoulder dislocation and sometimes a fracture and a dislocation will present together

Neer classification of proximal humerus fractures

• In Neer classification, Proximal humeral fractures are classified according to the number of parts involved
• Proximal humeral parts include: anatomical head, greater tuberosity, lesser tuberosity and the shaft
• For a part to be counted, it has to be displaced
• Displaced part is defined as a part displaced by more than 1 cm of translation or more than 45 degrees of angulation; if displaced less than that then the part is not counted
• Proximal humeral fractures are classified into: 
  • One-part fractures (minimally displaced fractures)
  • Two-part fractures
  • Three-part fractures
  • Four-part fractures

Minimally displaced fractures

Two-part fractures

• These classified into
  • Surgical neck fractures (most common proximal humeral fracture type)
  • Greater tuberosity fractures
  • Lesser tuberosity fractures 
  • Anatomical neck fractures

Three-part fractures

Four-part fractures

Not included in the Classification 

• A fracture dislocation: occurs when there is a fracture at the proximal humerus with a dislocation of the humeral head out of the glenoid
• Valgus impacted fracture has intact periosteal hinge medially and despite the displacement of the anatomical head, it can be reduced by surgical leverage on the hinge

Clinical features

• Patient present holding the affected arm close to the chest supported by the other hand and they complain of moderate to severe pain
• On looking to the upper arm, there might be a little swelling but no bruising initially but after a few hours, extensive and deep bruise may develop on the arm and down to the elbow
• Skin puckering anterolaterally suggest that deltoid muscle became interposed within the fracture (slows healing)
• Patient can’t move their shoulder
• Examine for neurovascular injuries
• Look for other injuries

Imaging

• X ray imaging
  • In elderly patients fracture lines are not seen well and it mostly one fracture line extending through the surgical neck
  • In younger patient, fracture lines are seen better and fragments are more clearly separated
  • Axillary and lateral shoulder views should be obtained to exclude dislocation and look for greater tuberosity displacement

• Ct scan shows fracture lines and displacement much better and it is essential for planning surgical reconstruction of complex fractures
• With repeated x rays through the healing process, humeral head is seen to be subluxated downward and that is due to muscle atony, it usually recovers once exercise are begun

Treatment

• These fractures can be treated by many options:
  • Sling or collar and cuff immobilization (non operative)
  • Percutaneous fixation (operative)
  • Open reduction and internal fixation (operative)
  • Arthroplasty (operative)
• Closed reduction is not required, because these fractures tend to realign over time as a result of the traction exerted by the weight of the arm, if a sling or collar and cuff is used
• There is no form of cast that is beneficial for these fractures
• Patients who are treated non operatively will get a satisfactory functional recovery most of the times while patients treated operatively will not regain a satisfactory function of the shoulder (stiffness, weakness and pain)

Minimally displaced fractures

• Minimally displaced fractures (one-part fractures)
  • Treated non operatively with sling immobilization for 4-6 weeks
  • Patient advised to remove their cuff or sling several times a day and begin pendular exercises immediately when pain allows and progression to shoulder exercises as soon as possible to prevent stiffness
  • Elbow and hand exercises are done from the start 

Two-part fractures treatment

• Surgical neck fractures treatment
  • Treated non operatively with sling immobilization for 4-6 weeks
  • If the fracture is unstable then operative method is used:
  • Percutaneous pins
  • Plate fixation (ORIF)
  • Intramedullary nails (ORIF)
  • Exercises started as soon as possible

• Greater tuberosity fractures treatment
  • If these fractures are not displaced or displaced by less than 0.5 cm then Treated non operatively with sling immobilization for 4-6 weeks
  • If displaced more than 0.5 cm then treated operatively with isolated screw fixation or non absorbable suture or tension band wiring
  • Sometimes these fractures are associated with anterior shoulder dislocation, and they reduce when the shoulder relocates in most of the cases

• Lesser tuberosity fractures 
  • Might be associated with posterior shoulder dislocation
  • If minimal displacement then Treated non operatively with sling immobilization for 4-6 weeks
  • If large fragment or displaced then treated with open reduction internal fixation

• Anatomical neck fractures
  • These are rare
  • If patient is young then open reduction and internal fixation
  • If old patient then prosthetic replacement (hemiarthroplasty) is preferable due to high risk of avascular necrosis

Three-part fractures treatment

• These usually involve displacement of the surgical neck and greater tuberosity and sometimes surgical neck and lesser tuberosity and they are difficult to reduce by closed methods
• So they are treated operatively with percutaneous pinning or open reduction and internal fixation using various methods
• If elderly patient then arthroplasty is needed

Four-part fractures treatment

• In this type, surgical neck and both tuberosities are displaced
• If patient is young then ORIF if proximal humerus is reconstructible, if not then hemiarthroplasty, if elderly then hemiarthroplasty
• These injuries are severe with high risk of complications such as vascular injuries, brachial plexus damage, chest wall injuries and late avascular necrosis of the humeral head

Complications 

• Neurovascular injuries: patient should be assessed for signs of these injuries, axillary nerve especially is at high risk of getting injured
• infection
• Non union: especially in two-part surgical neck fractures
• Malunion: causes little disability, it lead to loss of rotation which make it harder for the patient to reach behind neck or up the back
• Rotator cuff tear
• Adhesive capsulitis: it is Stiffness of the shoulder which is also called frozen shoulder and it is a common complication, especially in elderly patients, it can be minimized by starting exercises early
• Avascular necrosis
  • Avascular necrosis of the humeral head is segmental necrosis of devascularized anatomical head, this is seen by the X-rays.
  • Spontaneous revascularization commonly occurs but sometimes it doesn’t and the head collapses (in this case hemiarthroplasty is required)
  • AVN of the humeral head occurs in up to 30% in three-part fractures and up to 50% in four-part fractures
  • Avascular necrosis occurs when the vascular supply to the humeral head gets disrupted
  • Vascular supply to the humeral head arise from the anterior and posterior circumflex humeral arteries
  • Both are branches of the axillary artery
  • The arcuate artery (branch of the anterior circumflex humeral artery) will run in the bicipital groove to supply the humeral head
  • Humeral head also supplied from the tendon insertions into the two tuberosities and the periosteum
  • In three and four-part fractures, the anterior supply is compromised, and blood supply is mainly coming from the posterior side, this increase the risk for ischemia and AVN

Ischemia and AVN 

• Humeral head ischemia predictors (Hertel criteria)
  • < 8 mm of calcar length (calcar length is inferomedial cortical extension of the anatomical head to the surgical neck)
  • Disrupted medial hinge
  • Multiple part fractures
  • Displacement > 1 cm
  • Angulation > 45 degrees
• Hertel criteria predict ischemia but not AVN

Proximal humeral fractures in children

• In infants and children, proximal humeral fractures involve the physis and classified according to Salter-Harris classification
• In infants, it is mostly a transverse fracture (Salter-Harris I), reduction doesn’t need to be perfect and those fractures have good prognosis
• In children, it is mostly Salter-Harris type 2, reduction doesn’t have to be perfect too, and even if there is malunion, these fractures still have good prognosis due to the high potential for growth and remodeling
• Pathological fractures are possible due to the proximal humerus being a common site of a bone cysts and tumors, fracture through a simple cyst usually heals spontaneously if arm was rested in a sling for 4-6 weeks 

Course Menu

This article is apart from the Shoulder and Arm Trauma Free Course, which contain 10 lectures listed down below: