PROCEDURE 4 Proximal Humerus Fractures

Gerard March, Rod Martin, Scott J. Mandel

Hemiarthroplasty Operative Technique

Indications

PITFALLS

• Contraindications to consider with hemiarthroplasty for proximal humerus fractures include:

Active soft tissue infection

Chronic osteomyelitis

Rotator cuff muscle paralysis or massive rotator cuff tear

Severe glenoid damage either from fracture or osteoarthritis for which patient would require total shoulder replacement

Patient who is unable to participate in postoperative rehabilitation program (relative contraindication)

Prosthetic replacement of the proximal humerus for fractures is reserved for situations of poor bone stock and fracture patterns that will not allow stable internal fixation or will affect viability of the humeral head.

Indications for proximal humerus replacement include:

• Four-part humeral head fractures (associated with a high rate of avascular necrosis)

• Fracture-dislocation of the glenohumeral joint in an older, low-demand patient

• Humeral head-splitting or head-shearing fracture

• Fractures of greater than 40% of the humeral head articular surface

• Three-part humeral head fractures with poor bone quality

• Anatomic neck fractures in an older, low-demand patient

Controversies

• Note that isolated deltoid muscle paralysis is not considered a contraindication to arthroplasty for proximal humerus fractures—outcomes can be “of limited goals” but satisfactory.

• While preservation of the humeral head in 3-part fractures may be the preferred method of treatment, arthroplasty will have a more positive outcome in cases with:

Significant injury to articular segment

Blood supply injury

Severe osteoporosis or other bone quality issue

• It has been recommended that a subset of patients with “valgus impacted 4-part fractures” be treated with open reduction and internal fixation.

In these injuries, the humeral head is impacted upon the humeral shaft and, while the tuberosities are fractured, they are still in close approximation to the head and shaft.

Note that in these patients the head is not dislocated or displaced laterally and some contact with the glenoid is maintained.

If lateral displacement is found, then the medial periosteal vessels that perfuse the articular segment may be ruptured and avascular necrosis is more likely to result. Hence internal fixation would not be the treatment of choice.

This subset of 4-part fractures would not be considered true 4-part fractures under the Neer classification.

Examination/Imaging

DETAILED HISTORY AND PHYSICAL

Treatment Options

• Closed reduction with or without immobilization

• Open reduction and internal nonlocking fixation

• Open reduction and internal locking fixation

• Reverse ball-and-socket arthroplasty

• Intramedullary fixation

It is important to establish any history of seizure or head injury.

A complete neurovascular examination is performed, with a focus on the rotator cuff muscles.

• It must be remembered that the axillary nerve and artery are at a high risk for injury.

♦ Injuries to the axillary artery are to be considered limb threatening and must be dealt with as an emergency.

♦ Evaluation under emergent arteriography with possible vascular surgery consultation is necessary.

• Follow-up of any neurologic deficit should be completed with electromyographic analysis at 4–6 weeks. It should be noted, though, that neurologic evaluation should not delay definitive management of the fracture.

IMAGING STUDIES

Trauma series radiographs of the injured shoulder are obtained. These include:

• True anteroposterior view of the scapula, 30–40° oblique to the coronal plane of the body (Fig. 1)

• Trans-scapular lateral or scapular Y view

• Axillary view, taken with the arm abducted 20–30° and the x-ray tube placed in the axilla with the plate above the shoulder

Computed tomography is useful if the radiographs are not satisfactory for determining location of fracture lines, fracture displacement, or the quality of the articular surface. Figure 2 shows a three-dimensional reconstruction of the fracture shown in Figure 1.

Note the importance of imaging of the contralateral shoulder. This is helpful in determining the appropriate length, which is important for prosthesis placement.

FIGURE 1

FIGURE 2

Surgical Anatomy

The patient’s age or medical condition can affect the quality of the bone and the vascular supply to the humeral head (Fig. 3). In this setting internal fixation may become less attractive and prosthetic arthroplasty may be the preferred option.

• The arcuate artery, a continuation of the ascending branch of the anterior humeral circumflex artery, enters the humerus at the area of the intertubercular groove, and its branches supply both the greater and the lesser tuberosities.

• A smaller contribution to the blood supply of the humeral head comes from the posterior humeral circumflex arteries.

FIGURE 3

Positioning

PEARLS

• A sterile, padded Mayo stand can help with arm abduction; it lessens tension on the deltoid, making it easier to place sutures around/through the greater tuberosity posteriorly.

PITFALLS

• Full mobility of shoulder must be provided, especially in extension, to deliver the humeral shaft forward into the wound to clean the canal and insert cement.

The overall positioning goal is to have global access to the injured shoulder.

The involved shoulder should be elevated from the table and properly supported.

Commonly a table in the modified beach chair position is used that has a cutaway section at the shoulder allowing for greater access to the affected shoulder posteriorly (Fig. 4A and 4B).

The patient should be sitting at an approximate angle of 45°.

The head is secured in a neutral position.

The area is appropriately prepped and draped from the midclavicle to below the axilla. The arm is draped free, allowing for full movement throughout the procedure.

FIGURE 4

Portals/Exposures

Equipment

• Surgical table allowing for a modified beach chair position

• Positioning holder for the arm for hands-free positioning (optional)

• Padded Mayo stand

All 2-part, most 3-part, and some 4-part acute proximal humerus fractures are well treated by closed reduction as well as by open reduction and internal fixation techniques.

A long deltopectoral approach is used for a hemiarthroplasty.

INCISION

The incision starts just inferior to the clavicle (Fig. 5A and 5B).

It extends over the coracoid process, and ends laterally at the humeral shaft.

The incision may be extended to the clavicle or more distally along the humerus as needed.

FIGURE 5

DISSECTION

The cephalic vein is immediately identified in the deltopectoral muscular interval (Fig. 6A and 6B).

• Usually a fat stripe can be found on top of the vein and is a useful landmark to help locate it.

• Retraction of the cephalic vein is usually lateral.

Identification of the coracoid and its originating muscles (conjoined tendon) will define the medial limits of dissection.

• A broad retractor may be placed under the conjoined tendon and muscles in order to protect the medial neurovascular structures (Fig. 7A and 7B).

• A self-retaining retractor similar to a Charnley (Hawkins-Bell) retractor may be used.

The lateral limit of dissection is defined by placing a second broad retractor under the deltoid.

The glenohumeral joint can be easily identified by finding the long head of the biceps distally and following it proximally back to the superior aspect of the glenoid.

• Note that some surgeons prefer to routinely sacrifice the biceps during an arthroplasty procedure in order to remove it as a possible source of postoperative pain. However, this is not our preferred method.

FIGURE 6

FIGURE 7

FRACTURE EXPOSURE

Generally fracture hematoma needs to be identified and gently removed.

Large bone fragments should be retained as they may be important in ultimately determining the appropriate prosthetic height.

Identification of fracture fragments is usually dependent upon their position relative to the long head of the biceps.

The rotator interval can be breached at the area of the bicipital groove. Typically the trauma of the fracture has already separated this area.

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