Femoral Neck Fractures: Why This Part of the Hip Is So Hard to Treat

A slip on an icy driveway. A trip over the edge of a rug. For many older adults, a simple fall is all it takes to break a hip, and one of the most common places for that break is the femoral neck, the narrow section of bone just below the ball of the hip joint.

Femoral neck fractures can be harder to heal than many other broken bones because the area has a limited blood supply and little room for error. The good news is that surgeons have effective options, either repairing the bone or replacing the hip, and most people can return to walking after treatment.

The thigh bone, or femur, is the longest, strongest, and heaviest bone in the body. It can absorb forces several times a person's body weight.

Near its top, though, the femur has a weak point: the femoral neck. This short, angled stretch of bone connects the main shaft of the femur to the femoral head, the rounded ball that fits into the hip socket. The femoral neck works like a support beam, allowing the leg to rotate and move through a wide range of motion. Every step, jump, or quick pivot puts stress on this narrow section of bone.

“When you look at human anatomy, the design of the femoral neck is brilliant for mobility, but it doesn’t leave much room for error,” explains Daniel Wiznia, MD, a Yale Medicine orthopedic surgeon specializing in hip and knee reconstruction and co-director of the Yale Avascular Necrosis and Osteonecrosis Program. “It bears the brunt of each step we take, which means when something goes wrong here, our priority is finding a solution that safely gives patients their mobility and quality of life back.”

In older adults, most femoral neck fractures happen after a simple fall. As people age, bone density often decreases, especially in people with osteoporosis, a condition that makes bones thinner and weaker. Weaker bone means the femoral neck can break from an everyday accident.

In younger people, femoral neck fractures are less common and usually result from high-energy injuries, such as a car accident or a serious fall.

A hip fracture is a medical emergency. Call 911 or go to an emergency room if, after a fall or injury, someone has:

• Severe pain in the hip or groin
• Inability to stand or put weight on the leg
• A leg that looks shorter than the other or turns outward

Prompt treatment matters. Surgery is usually done within a day or two of the injury.

Two features of the femoral neck make these fractures especially challenging: its blood supply and how the bone heals.

Many large bones get blood from the surrounding muscles and tissues. The femoral head, however, depends almost entirely on tiny blood vessels that run along the outside of the narrow femoral neck.

When the femoral neck breaks, those blood vessels can be stretched, pinched, or torn. If blood flow to the femoral head is cut off, the bone tissue begins to die and is unable to heal the tissue.

When blood flow to the top of the femoral head gets cut off, orthopedic surgeons face two major challenges: bone tissue death and failed bone healing.

Most bones are covered by a tough outer layer called the periosteum. When a bone breaks, this layer helps form a temporary bridge of new tissue that holds the pieces steady while new bone grows.

However, the femoral neck sits inside the hip joint capsule, where it’s surrounded by joint fluid and has little of this healing layer. As a result, the bone must heal from the inside, which is slower and requires the broken pieces to stay still and pressed tightly together.

If the pieces shift, the fracture may not heal. This is called a nonunion. A nonunion can cause ongoing pain, an unstable hip, and difficulty walking, and it often requires more surgery.

When deciding on treatment, orthopedic surgeons consider your age, overall health, activity level, and how far the broken pieces have moved out of place.

For younger, active patients, the main goal is usually to save the natural hip joint. Surgeons line up the broken pieces and hold them in place with metal screws or pins. Even when some blood flow remains, these fractures are challenging to heal. Bone tissue death, known as avascular necrosis, happens when starving bone cells begin to die from lack of blood supply.

Over time, the dead bone affected by avascular necrosis loses its structural strength. Without treatment, the femoral head can collapse, leading to painful joint arthritis. If untreated, the ball portion of the hip joint will collapse. At that point, hip replacement surgery is often the only option.

“Avascular necrosis can sound overwhelming to a patient,” says Dr. Wiznia, who is also an associate professor of orthopaedics and rehabilitation at Yale School of Medicine. “What we try to reassure them is that catching it early gives us options. My goal is always to meet patients where they are, whether that means preserving their natural bone whenever possible or helping them navigate a joint replacement so they can get back to living without pain.”

Because these patients are at risk for avascular necrosis, they’re typically monitored for several years after surgery.

For older adults, especially when the broken pieces have shifted out of place, repairing the bone is less likely to succeed. The bone may be too weak to hold screws, and the blood supply is more likely to be damaged. In these cases, surgeons usually recommend replacing the joint instead. Options include a partial hip replacement, which replaces only the ball and femoral neck, or a total hip replacement, which replaces both the ball and the hip socket.

The choice between the two often depends on a patient’s activity level and overall health.

“There is no one-size-fits-all answer here, and that’s a good thing,” Dr. Wiznia says. “When I sit down with a patient, we aren’t just looking at an X-ray. We're looking at their lifestyle, their goals, and what will give them the smoothest recovery. For a younger patient, we fight hard to save their natural bone. For an older individual, replacing the joint likely offers the fastest, most reliable path back to walking comfortably.”

“Every surgical choice is made in partnership with the patient,” Dr. Wiznia adds. “With medical advancements, modern implants, robotic assistance for precision, and 3D surgical planning, we can tailor a treatment to each person’s unique anatomy better than ever before. My job is to make sure they feel supported and confident every step of the way.”

Most patients begin moving and working with a physical therapist soon after surgery to rebuild strength and walking ability. Recovery time varies depending on the type of surgery and a person’s overall health.

Patients whose bone was repaired will have follow-up visits and X-rays to make sure the fracture is healing and to watch for signs of avascular necrosis. Contact your doctor if you develop new or worsening pain in the hip or groin after treatment.

Not every fracture can be prevented, but you can lower your risk by:

• Asking your doctor whether you should be screened for osteoporosis
• Following any treatment your doctor recommends for low bone density
• Staying active with exercises that build strength and balance
• Reducing fall risks at home, such as loose rugs, poor lighting, and clutter