A proximal humerus fracture is a common injury to the shoulder. Especially common in elderly individuals due to osteoporosis, proximal humerus fractures are among the most common broken bones in the shoulder. In fact, in patients older than 65, proximal humerus fractures are the third most common broken bone (after hip fractures and wrist fractures).
A proximal humerus fracture occurs when the ball, of the ball-and-socket shoulder joint, is broken. The fracture is actually at the top of the arm bone (the humerus). Most proximal humerus fractures are non-displaced (not out of position), but about 15-20 percent of these fractures are displaced, and these may require more invasive treatment.
The most significant problem with proximal humerus fractures is that treatment is very limiting, and the outcomes are often fair or poor. Many patients who sustain this injury do not regain full strength or mobility of the shoulder, even with proper treatment.
What Is a Displaced Proximal Humerus Fracture?
When the bone is not in proper alignment, the fracture is called displaced. In proximal humerus fractures, the severity is often described by how many of the major parts of the proximal humerus fracture are displaced. There are four “parts” of the proximal humerus, so a displaced fracture can either be 2-part, 3-part, or 4-part (a non-displaced fracture is, by definition, 1-part). In general, the more displaced parts, the worse the prognosis.
The parts of the proximal humerus are called the tuberosities (the greater and lesser tuberosity), the humeral head (the ball of the shoulder), and the humeral shaft. The tuberosities are next to the ball and are the attachments of the important rotator cuff muscles.
For a part to be considered displaced, it either has to be separated from its normal position by more than a centimeter or rotated more than 45 degrees.
About 80 percent of proximal humerus fractures are non-displaced (not out of position), and these can almost always be treated in a sling. Typical treatment is to rest the shoulder in the sling for two to three weeks, and then begin some gentle range-of-motion exercises. As healing progresses, more aggressive shoulder strengthening exercises can resume, and full healing typically takes about three months.
In more severe injuries where the bone is displaced (out of position), it may be necessary to realign or replace the damaged bone. Determining the best treatment depends on many factors including:
- Age of the patient
- Hand dominance
- Activity level of the patient
- Degree of displacement of the fracture
The options for surgery include realigning the bone fragments and holding them in position with metal implants, or a shoulder replacement procedure is performed. If the fragments of bone can be fixed, either pins, screws, wires, large sutures, or a plate will be used to hold the bones in place. Plates and screws have become much more common as the plating technology has improved.
If there are concerns about repairing the bone, it may be decided to perform some type of shoulder replacement. If a replacement procedure is recommended, options include a standard shoulder replacement, a hemiarthroplasty, or a reverse shoulder replacement.
The specific recommendation for which type of surgery is best depends on many factors including the type of break and the specific patient. For example, reverse shoulder replacements can be excellent treatments but are reserved for elderly, less-active patients.
Unfortunately, proximal humerus fractures are often serious injuries, especially when the alignment of the bone has shifted significantly. Declines in shoulder function are not uncommon, and people who sustain these injuries often do not recover their full strength or mobility of the joint. Because of the trauma to the shoulder joint, the development of early arthritis is also a common complication of these injuries.
Some of the complications directly related to surgical treatment of proximal humerus fractures include infection, wound healing problems, nerve injury, and lack of healing of the bone. The last one of these, called a nonunion, occurs when the bone fails to unite, and the fracture comes apart again.
Metal hardware used to repair a broken bone is not meant to be a permanent solution, rather it holds the bone in place while healing takes place. If the bone does not heal completely, then the metal implants will eventually fail, and usually, repeat surgery needs to be considered.