A humeral head fracture is a break at the top of the upper arm bone, right where it forms the ball of the shoulder joint. It’s one of the most common fractures in adults, particularly in women over 65 and young people involved in high-energy accidents. Most of these fractures (80% to 90%) heal well without surgery, though more complex breaks can require significant intervention.
Where the Fracture Happens
The humerus is the long bone running from your shoulder to your elbow. At the very top sits the humeral head, a smooth, rounded surface that fits into the shoulder socket like a ball in a cup. Just below the humeral head is a narrow region called the anatomical neck, which separates the head from two bony bumps called the greater and lesser tuberosities. These tuberosities serve as anchor points for the rotator cuff muscles that control shoulder movement. Below the tuberosities is another narrowing called the surgical neck, named because it’s especially prone to fractures.
When doctors refer to a “humeral head fracture” or “proximal humerus fracture,” they’re talking about a break anywhere in this top region. The fracture might run through the humeral head itself, snap through the surgical neck, or crack off one or both tuberosities. The location and number of broken pieces determine how serious the injury is and what treatment looks like.
Who Gets These Fractures
These fractures follow a pattern that doctors describe as bimodal, meaning they cluster in two distinct age groups. In people under 30, the cause is typically high-energy trauma: car accidents, sports collisions, or falls from height. In people over 65, a simple fall from standing height is often enough, because osteoporosis has weakened the bone. Women are affected roughly 1.6 times more often than men, largely due to higher rates of osteoporosis after menopause. The incidence has been climbing in recent years, rising from about 7,100 cases in 2017 to 8,450 in 2022 in one large U.S. dataset.
How Fracture Severity Is Classified
Doctors use a system that focuses on how many bone fragments have shifted significantly out of place. A fragment counts as “displaced” if it has moved more than 1 centimeter apart from its neighbor or tilted more than 45 degrees.
- One-part fracture: The bone is cracked, but no pieces have shifted out of position. This is the most common type and the easiest to treat.
- Two-part fracture: One segment has displaced. That segment could be the surgical neck, the greater tuberosity, the lesser tuberosity, or the articular surface (the smooth ball of the joint).
- Three-part fracture: One tuberosity has displaced along with a surgical neck fracture. The remaining tuberosity stays attached, which causes the humeral head to rotate abnormally.
- Four-part fracture: All four segments (both tuberosities, the articular surface, and the shaft) have displaced. The ball of the joint typically shifts sideways and loses contact with the shoulder socket entirely.
The higher the part count, the more disrupted the blood supply to the bone and the greater the risk of complications.
Symptoms and Diagnosis
The most obvious signs are immediate shoulder pain, swelling, and redness in the upper arm. Most people find it impossible to lift the affected arm and instinctively hold the elbow of the injured side with the opposite hand for support. Bruising often spreads down the arm and sometimes into the chest wall over the first few days.
Doctors check nerve and blood vessel function carefully, because the nerves running through the armpit area sit close to the fracture site and can be stretched or pinched. They’ll test sensation on the outside of the shoulder and check your ability to contract the muscle that caps the shoulder (the deltoid).
Diagnosis relies on X-rays taken from multiple angles, typically including front-to-back views with the arm rotated inward and outward, a view from below through the armpit, and a lateral view looking across the shoulder blade. When the X-rays don’t clearly show how many fragments exist or how far they’ve moved, a CT scan provides a three-dimensional picture that helps guide treatment decisions.
When Surgery Isn’t Needed
The majority of humeral head fractures are one-part fractures where the pieces haven’t significantly shifted, and these respond well to conservative treatment. A sling keeps the arm immobilized during the initial healing phase, typically for a few weeks, followed by a gradual progression of physical therapy. Nondisplaced tuberosity fractures, surgical neck fractures that still have bone-to-bone contact without gross instability, and stable impacted fractures all tend to heal satisfactorily without an operation.
Early mobilization matters. Starting gentle, guided movement as soon as the fracture is stable enough helps prevent the shoulder from stiffening up. Physical therapy usually begins with passive range of motion, where a therapist moves your arm for you, before progressing to active exercises where you move it yourself. The timeline varies, but most people see meaningful functional improvement over 3 to 6 months.
When Surgery Is Recommended
Surgery enters the picture in three main scenarios: when the humeral head is severely compromised (from a fracture-dislocation, deep impaction, or a split through the head itself), when the shaft and head are grossly unstable with no bone contact between them, or when the tuberosities have shifted far enough that they would heal in a position causing lasting impingement and poor function.
For displaced three-part and four-part fractures, the two primary surgical options are internal fixation and shoulder replacement. Internal fixation uses a metal plate and screws to hold the fragments in their anatomical position while the bone heals. The goal is to restore the original anatomy, preserve the natural joint, and maintain rotator cuff function. This approach tends to work best in younger, active patients with good bone quality.
For patients 65 and older, especially those with poor rotator cuff condition or a humeral head that can’t be reconstructed, a reverse shoulder replacement is often the better choice. This prosthetic design flips the ball-and-socket arrangement so the deltoid muscle, rather than the rotator cuff, powers arm movement. Research consistently supports this approach for older adults with complex fractures, as it provides reliable pain relief and functional recovery without depending on rotator cuff muscles that may already be worn or torn.
Possible Complications
The complication that concerns surgeons most is loss of blood supply to the humeral head, a condition called avascular necrosis. The bone dies when its blood supply is disrupted by the fracture. The risk scales directly with fracture complexity: roughly 1% for two-part fractures, up to 25% for three-part fractures, and as high as 77% for four-part fractures in some studies. In practice, surgical technique plays a huge role. One study found that when surgeons achieved near-perfect realignment (less than 2 millimeters of displacement) in high-risk four-part fractures, avascular necrosis dropped to 0%, compared to 32% when alignment was less precise.
Shoulder stiffness is another common issue, particularly when immobilization lasts too long or physical therapy starts too late. The shoulder joint is inherently prone to tightening up after injury, and regaining full range of motion requires consistent rehabilitation over months. Some degree of permanent motion loss is not unusual, especially with more complex fractures, though most people recover enough function for daily activities.
Malunion, where the bone heals in a shifted or rotated position, can cause ongoing pain and mechanical problems in the shoulder. Middle-aged patients (40 to 65) appear to have higher rates of healing complications, including nonunion, where the bone fails to heal at all. This is a somewhat counterintuitive finding, as older patients with weaker bone might seem more vulnerable, but the pattern has been confirmed across multiple studies.
What Recovery Looks Like
For non-surgical fractures, the sling phase typically lasts 2 to 4 weeks, though your doctor may adjust this based on fracture stability. Physical therapy begins with pendulum exercises and passive stretching, then progresses to active-assisted motion, active motion, and eventually strengthening. Most people notice the biggest gains in the first 3 months, with continued improvement for up to a year.
After surgery, the rehabilitation timeline depends on the procedure. Internal fixation generally allows earlier motion because the hardware stabilizes the fracture. Shoulder replacement patients follow a structured protocol that protects the repair of the tuberosities (which are sewn back onto the prosthesis) while gradually building strength and range of motion. Full recovery from either surgical approach typically takes 6 to 12 months, and some patients continue to see minor improvements beyond that window. The 80% to 90% good-outcome rate for conservative treatment sets a useful benchmark: most people with simpler fractures return to near-normal shoulder function, while complex fractures treated surgically generally achieve meaningful pain relief and enough mobility for everyday tasks, even if some overhead reaching ability is permanently reduced.