- Relevant Anatomy of Proximal Humerus
- Mechanism of Injury of Proximal Humerus Fractures
- Clinical Presentation of Proximal Humerus Fractures
- Imaging of Proximal Humerus Fractures
- Classification of Proximal Humerus Fractures
- Treatment of Proximal Humerus Fracture
- Complications of Proximal Humerus Fracture
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Proximal humerus fractures account for approximately 5% of all fractures. Proximal humeral fractures generally occur in older patients. This is so because older patients have osteopenic or osteoporotic bones which get damaged easily by trivial trauma. High energy trauma can produce these fractures in any person of any age.
Relevant Anatomy of Proximal Humerus
Humerus bone extends from shoulder to elbow joint and participates in formation of both joints.
Proximal humerus may be divided into four major fragments
- Humeral head
- Lesser tuberosity
- Greater tuberosity
- Shaft separated at surgical neck humerus
The main blood supply to the humeral head is from the anterior humeral circumflex artery. The arcuate artery arising from the anterior circumflex perfuses the humeral head.
Mechanism of Injury of Proximal Humerus Fractures
Most of these fractures occur due to a simple fall on the arm. Strong muscular contraction might be responsible in the setting of electric shock or seizure.
Most fractures are believed to result from indirect violence.
Muscle forces contribute to their displacement. In proximal humerus fracture, pectoralis major draws the shaft of humerus anteriorly and medially. The greater tuberosity may be pulled posteriorly by the infraspinatus and superiorly by the supraspinatus. The subscapularis tends to rotate internally a head segment where lesser tuberosity remains attached.
Clinical Presentation of Proximal Humerus Fractures
Most patients with acute proximal humerus fracture present with a painful, swollen arm. There could be bruises over the injured area or they might develop over a period.
Apart from the injured area the patient has presented with, the patient should be assessed for neck and chest injury. It goes without saying that the distal limb should be examined for any neurovascular involvement.
The most commonly injured nerve in proximal humerus fracture is the axillary nerve.
If the patient has amnesia, bilateral injuries, or a posterior fracture-dislocation, a seizure disorder or electric shock must be ruled out.
General state of the patient and the local condition of the limb would affect the treatment decision.
Complicating factors are such as severe soft tissue injury, whether open or closed and the presence of neurovascular injury.
Stability of limb can be checked by careful manipulation of the limb. In grossly unstable fractures, the humeral shaft may be easily palpated in the deltoid muscle mass, moving independently of the proximal fragment.
Imaging of Proximal Humerus Fractures
The ordered radiographs for these fractures must include an anteroposterior view of the scapula, a lateral “Y-view” of the scapula, and an axillary view.
If a good radiograph fails to detect anything CT scans are most helpful in checking for dislocations, in ruling out a glenoid fracture, and in assessing posterior retraction of the greater tuberosity.
Classification of Proximal Humerus Fractures
Most commonly used classification method of proximal humerus fracture is that of Neer’s. Fractures are classified by evaluating displacement of any of the four principal fragments (head, shaft, greater tuberosity, and lesser tuberosity).
All fractures in which no segment is displaced more than 1 cm or is rotated more than 45 degrees are considered minimally displaced and are considered together as one-part fractures, regardless of the number or location of fracture lines.
Two-Part Proximal Humerus Fracture
A single segment is displaced in a two-part fracture. This occurs most commonly with surgical neck displacement, in which the shaft is separated from the head and both attached tuberosities. It is also seen with greater tuberosity displacement.
If the head is split or has suffered an impression fracture, it is considered to have an articular loss.
Three-Part Proximal Humerus Fracture
A fracture with three-part displacement has the shaft and either the greater (most often) or lesser (rarely) tuberosity separated from the head, to which one of the tuberosities remains attached.
Three-part fractures involve a fracture of surgical neck of humerus along with a fracture of either greater tuberosity or lesser tuberosity. While surgical neck is quite displaced to miss out, a small degree of tuberosity displacement may be easily missed and may require additional radiographic views.
Open reduction and internal fixation is the preferred treatment. Failure of the treatment may lead to hemiarthroplasty i.e. replacement of the head component with a prosthesis.
Four-Part Proximal Humerus Fracture
A four-part fracture is present when the head is separated from all other segments, even if the tuberosities are together (thus, there can be three pieces, one of which comprises both tuberosities). The head is completely dislocated out of the glenoid and is devoid of any soft tissue attachment. In the “valgus-impacted” four-part fracture, the head is rotated to face upward Although the head is completely out of contact with the glenoid.
In this injury, there is a fracture of the head which results in its separation from the rest of the structures and there are fractures of lesser and greater tuberosities. Very often, the head is dislocated anteriorly, laterally, or posteriorly. The greater and lesser tuberosities are not always separated, and they may be held together by muscle attachments.
This injury is best shown by anteroposterior views. A computed tomogram clearly delineates the fracture.
Four-part fractures have not done well with nonoperative treatment and repaired fractures do better than nonoperative cases.
Historically, results of surgery of four-part fractures have not been found good but improved techniques of fixation and better patient selection have brought better results.
Avascular necrosis of the head is a significant problem in these fractures.
Displaced Fractures of Tuberosity
Fracture of greater tuberosity is commoner than lesser tuberosity.
The greater tuberosity is displaced superiorly by the supraspinatus or posteromedially by the infraspinatus and teres minor. In lesser tuberosity fractures, on the other hand, displacement tends to be medial because of the pull of the subscapularis.
7% to 15% of glenohumeral dislocations have an associated greater tuberosity fracture.
Treatment of Proximal Humerus Fracture
Treatment Decisions based on Fracture Pattern
Stable fractures and minimally displaced fractures are usually treated with non-operative means.
Proximal humerus fracture, in quite a number of cases, can be managed with nonoperative treatment. The principle of treatment by conservative methods is early protection combined with gradual mobilization.
Elderly people accept nonoperative treatment quite well. Even deformities like displacement and angulation are taken very well by these patients.
Most patients are placed in a sling for the first week to 10 days. Closed reduction of surgical neck fracture may be attempted in patients who would tolerate it. Hand, wrist, and elbow motion begins immediately. Radiographs are done after 3 or 4 weeks. If the fracture configuration has not worsened and the feel is solid, gentle assistive exercises like pulley elevation, external rotation with a stick, extension with a stick are begun along with formal physical therapy.
Gradual stretching exercises are also begun and continued till maximum range of motion is achieved.
Treatment of fractures with major displacement depends on the fracture configuration
Lesser Tuberosity Fractures
An isolated lesser tuberosity fracture is frequently associated with posterior dislocation of the shoulder and it should be looked for. Unless associated with some other major displaced fragment, closed treatment only is indicated.
Greater tuberosity fractures occur more commonly in association with anterior dislocation of the shoulder.
If loss of function of the rotator cuff and mechanical block by fracture fragment is an issue, consider surgery. Otherwise, the fracture can be managed with non-operative treatment
Surgical Neck Fractures
It is a relative indication for surgery, especially in young patients with good bone
Displaced fractures through the anatomical neck are associated with a high incidence of avascular necrosis and nonunion due to instability. Surgery should be performed if closed manipulation fails to restore the local anatomy.
The three-part fracture consists of a large displaced proximal fragment through the surgical neck, associated with an avulsion of either the lesser or greater tuberosity or both.
If the lesser tuberosity containing the subscapularis is avulsed, the proximal fragment is externally rotated. If the greater tuberosity is avulsed, the proximal fragment is internally rotated. This happens due to pull of respective attached tissues.
Open reduction and internal fixation should always be performed if delayed union and nonunion are to be prevented.
The four-segment fracture is the most difficult to treat as the treatment is commonly associated with delayed union or nonunion or/ and avascular necrosis of the humeral head. The pathognomonic feature is the small, crescentic, proximal articular fragment severed from the anatomical neck of the humerus.
The fracture is mostly treated by surgical methods.
Fracture-Dislocation of Shoulder
Two-Part Fracture Dislocation
The two-part anterior fracture-dislocation is associated with an avulsed greater tuberosity. Closed reduction with no surgical intervention except when the fragment becomes irreducible due to soft tissue interposition [long head of biceps tendon] is the treatment.
A two-part posterior fracture-dislocation is associated with an avulsed lesser tuberosity. Closed treatment is usually sufficient.
Three-Part Fracture Dislocation
In the three-part fracture dislocation, closed manipulation with general anesthesia may restore the proximal fragment to an anatomical position. If the proximal fragment cannot be reduced because of soft tissue interposition, then the open reduction is mandatory.
Four-Part Fracture Dislocation
Open reduction is usually indicated, but the avascular necrosis of the humeral head is likely.
Nonoperative Treatment of Proximal Humerus Fractures
Proximal humerus fractures may be treated nonoperatively with an initial period of immobilization followed by an early motion. Initial immobilization may be achieved with a sling, shoulder immobilizer, or a sling with an accompanying swathe.
Gentle range-of-motion exercises are begun after 7-10 days and progress to physiotherapy is made after 3 weeks.
Indications for nonoperative treatment of proximal humerus fractures are
- <5mm of superior or 10 mm of posterior greater tuberosity displacement inactive people
- <10 mm of superior displacement in the nondominant arm of sedentary patients
- Elderly patients with less than half shaft diameter displacements and less than 45-degree angulation in dominant arm in young people.
- Lesser demands and expectation of the patient
- If the patient is unable to tolerate surgery and anesthesia
- The patient cannot participate in rehabilitation
Surgical Treatment of Proximal Humerus Fractures
Different methods of fixation of proximal humerus fracture include
- Closed reduction
- Closed reduction and percutaneous fixation
- Open reduction with internal fixation
- Humeral head replacement
Greater tuberosity fractures, 2-part
Displacement of greater tuberosity fractures usually is posterior and superior. Attempts at closed reduction are unsuccessful, except in cases with an associated anterior dislocation, in which closed reduction of the fragment may be adequate.
Open treatment is recommended for greater tuberosity fractures displaced 5 mm or more.
Lesser tuberosity fractures, 2-part
Displacement of the lesser tuberosity often is medial, and closed reduction with internal rotation often can place the tuberosity in a satisfactory position. Therefore, open treatment of these fractures may not be necessary.
Surgical neck fractures, 2-part
Closed reduction, closed reduction, and percutaneous pinning and open reduction and internal fixation with pre-contoured proximal humerus locked plates can be considered.
Anatomic head fractures, 2-part
This rare injury can occur in conjunction with humeral head dislocation. In general, it has a very guarded prognosis because of the compromised blood supply to the head segment.
Elderly patients with poor tissue quality and osteoporosis usually require arthroplasty. In younger patients, every effort should be made to retain the humeral head. The possibility of hemiarthroplasty or reverse shoulder arthroplasty in case the decision is made intraoperatively that fixation seems inadequate.
These fractures require open surgical management in a line similar to three-part proximal humerus fracture
Surgical Techniques for Fracture Proximal Humerus
Closed reduction percutaneous pinning
This technique uses closed reduction and percutaneous insertion of pins. Threaded pins are used and cartilage is not controlled. There is a risk of injury to axillary nerve biceps tendon, a musculocutaneous nerve, and cephalic vein.
Open Reduction and Internal Fixation
- Anterior deltopectoral approach
- Deltoid Muscle Splitting With or Without Acromion osteotomy
Open reduction and internal fixation is indicated in greater tuberosity and valgus-impacted 4-part fractures
The fractures can be fixed by heavy nonabsorbable sutures, screw only or locking plate.
Proximal humeral nail is used in trauma or pathologic fractures
- Total shoulder arthroplasty
- Reverse shoulder arthroplasty
Complications of Proximal Humerus Fracture
This usually results from muscle atony, blood in the joint, capsular tears, or any combination of these conditions. Treatment consists of sling support, deltoid isometrics, and observation. Instability should not be ignored.
Incorrect diagnosis, poor reduction, inadequate fixation are frequent causes of malunion. Treatment depends on the severity of the malunion. For less severity, the malunion can be left as such. Sevre malunions can be treated by release of adhesions with or without osteotomy. Trimming of prominences can also be considered.
Nonunion is rare in proximal humeral fractures. Early motion and poor bone stock are the frequent causes. It should be treated by surgical methods including humeral head replacement when necessary.
it is more common in three-part and four-part fractures. Most patients are followed and watched. Gentle stretching exercises and mild analgesics are the usual treatment in most of the patients. If collapse occurs or pain becomes unbearable, humeral head replacement is considered. In case of development of glenoid arthritis, a total shoulder replacement considered.
Due to a large envelope of soft issues infection in the shoulder has a low rate. ANtibiotics, debridement and regular wound care are basic management techniques.
As many as 45% of patients with surgical neck fractures or glenohumeral dislocations have been found to have some degree of nerve injury. The risk is more in elderly patients or when a hematoma develops.
When associated with closed fracture, the prognosis for recovery is good, and observation is indicated. Splints may be used to support weak joints, and therapy is used to maintain passive motion.
Arterial injury from displaced fractures is common.
Could occur following avascular necrosis or hardware penetrating joint.