Bone Spurs in the Hip and Knee: What Do They Really Mean?

Many patients become alarmed when they hear the term “bone spur.” They picture a sharp piece of bone growing where it doesn't belong and assume it's the main cause of their pain. In reality, bone spurs are usually not the primary problem — they're often a sign that the joint has been under abnormal stress for many years. Understanding why they form explains what's really happening inside the hip or knee.

Why do bone spurs form?

Bone is living tissue that constantly responds to stress. A principle known as Wolff's Law says bone adapts to the loads placed on it — when it experiences increased stress, it gets stronger and lays down extra bone to help support the forces across the joint. Bone spurs (also called osteophytes) are part of that adaptive response.

Bone spurs in the hip

When bone spurs develop around the hip, they often signal that the ball and socket are no longer moving smoothly. As cartilage wears away and arthritis develops, the body responds by creating extra bone around the edges of the joint — around the femoral head (ball), the femoral neck, and the acetabulum (socket). Generally, the larger the spur formation, the more likely significant arthritis is present.

In some patients, spurs form because of abnormal hip mechanics such as femoroacetabular impingement (FAI), where the ball and socket repeatedly rub against one another. Over time this can create a vicious cycle: abnormal contact leads to more bone formation, which leads to even more abnormal contact.

Bone spurs in the knee

Bone spurs in the knee commonly develop as arthritis progresses. The knee depends on healthy cartilage to cushion the femur and tibia; as that cartilage wears away, forces across the joint become increasingly concentrated, and the body forms spurs around the edges. They're commonly seen with:

We also frequently see spurs when the knee begins to subluxate — gradually shifting out of its normal position over many years. As the knee becomes less stable and its mechanics worsen, the body compensates by building extra bone around the joint margins. Long-standing malalignment is its own topic — see knee osteotomy for how alignment problems drive single-compartment wear.

Are bone spurs causing my pain?

Sometimes — but usually not directly. Most of the pain associated with arthritis comes from the underlying joint damage rather than the spur itself. The true problem is usually:

• Loss of cartilage
• Bone-on-bone contact
• Joint inflammation
• Joint deformity
• Abnormal joint mechanics

The bone spur is often simply evidence that these processes have been happening for a long time. That's why removing a spur alone rarely solves the problem if the underlying arthritis remains.

Can bone spurs become severe?

Absolutely. As arthritis progresses, spurs often become larger and more extensive. On X-rays of advanced arthritis we frequently see large osteophytes alongside joint-space narrowing, bone hardening (sclerosis), cyst formation, and joint deformity. These findings tell us the body has been adapting to abnormal loading for many years — they're a picture of the process, not just the spur.

What happens to bone spurs during joint replacement?

One advantage of hip and knee replacement is that we address both the damaged joint and the spurs. Spurs are routinely removed as part of the procedure — but the goal isn't simply to shave off the spur; it's to restore the joint's normal mechanics. By replacing the worn surfaces and correcting alignment, we eliminate the underlying problem that caused the spurs to form. In practice that means:

The result is a stable, well-functioning joint without the abnormal stresses that led to spur formation in the first place. Of course, surgery is the last step — most arthritis is managed for years with non-surgical care first.

The bottom line

Bone spurs are often misunderstood. They're usually not the primary problem — they're a sign that the hip or knee has been under abnormal stress over time, and the body's attempt to protect and stabilize a joint that's no longer working normally. When we see spurs on an X-ray, we don't fixate on the spur; we look for the underlying cause — arthritis, instability, deformity, cartilage loss, or abnormal mechanics.