A bone bruise is an injury inside the bone itself, where tiny fractures in the spongy inner tissue cause bleeding, swelling, and fluid buildup beneath the bone’s hard outer surface. Unlike a regular bruise on your skin, a bone bruise won’t show visible discoloration. It also won’t appear on an X-ray. The injury is real and often painful, but it’s hidden, which is why doctors sometimes call it an “occult” bone injury.
What Happens Inside the Bone
Bones aren’t solid all the way through. Beneath the dense outer shell is a lattice of spongy tissue called trabecular bone, filled with marrow and small blood vessels. When a strong impact compresses this inner structure, it creates microscopic fractures in the lattice. Blood leaks from damaged vessels into the surrounding marrow, and fluid accumulates as the body mounts an inflammatory response. This combination of bleeding, swelling, and tiny structural breaks is what makes up a bone bruise.
The injury falls on a spectrum between a simple soft tissue bruise and a full fracture. The outer shell of the bone stays intact, which is why X-rays come back normal. But the internal damage is significant enough to cause deep, aching pain that persists far longer than a regular bruise.
How It Feels
The hallmark of a bone bruise is deep pain at the injury site that worsens with pressure or weight bearing. The area is typically tender to the touch, and you may notice swelling of the surrounding soft tissue, though the skin itself may look normal. The pain often feels like it’s coming from deep inside the joint or limb rather than from the surface, which can make it hard to pinpoint.
What sets a bone bruise apart from a muscle or skin bruise is how long the pain lasts. A standard bruise resolves in a week or two. A bone bruise keeps hurting for weeks, and in many cases, months. The pain tends to be worse with activity and improve with rest, but it rarely disappears completely until the bone has healed internally.
Common Causes
Bone bruises typically result from direct impact, falls, sports collisions, or twisting injuries that force joint surfaces to slam together. The knee is one of the most frequently affected areas, particularly during ligament injuries. When the anterior cruciate ligament (ACL) tears, the shinbone and thighbone often crash into each other as the joint shifts out of alignment. MRI scans detect bone bruises in roughly 85% of acute ACL tears, based on a review of nearly 4,000 cases.
Other common sites include the ankle, hip, wrist, and heel. Any bone that absorbs repeated stress or a sudden forceful blow can develop a bruise. Runners and athletes in high-impact sports are at higher risk, as are people who suffer falls onto hard surfaces.
Why X-Rays Miss It
Standard X-rays capture the dense outer shell of bone well, but they can’t detect the fluid, bleeding, and microscopic damage happening inside the marrow. Because the outer bone remains intact in a bone bruise, the X-ray looks completely normal.
MRI is the only reliable way to diagnose a bone bruise. On MRI, the injured area shows up as a bright signal on certain image types, reflecting the free water from swelling, bleeding, and inflammation trapped in the marrow. Radiologists sometimes need to use specific techniques like fat suppression to avoid missing the bruise, since the fluid and surrounding fatty marrow can look similar on standard images. If your doctor suspects a bone bruise after a normal X-ray, an MRI is the logical next step.
How Long Recovery Takes
Bone bruises heal slowly compared to soft tissue injuries, and the timeline varies widely depending on the severity and location. Mild bone bruises may resolve in a few weeks. More severe ones take considerably longer.
A study published in the American Journal of Roentgenology tracked bone bruises of the knee over time and found a median healing time of about 42 weeks, or roughly 10 months. Nearly 23% of the bone bruises in that study were still visible on MRI after a full year. These numbers reflect knee injuries specifically, which tend to bear a lot of load, but they illustrate an important point: bone bruises can linger far longer than most people expect.
The slow healing happens because trabecular bone has a limited blood supply compared to muscle or skin. The microscopic fractures need to knit back together while the fluid and blood in the marrow gradually reabsorb. Rushing back to full activity before the bone has healed can extend recovery or worsen the injury.
Treatment and Activity
There’s no way to speed up the biological healing of bone, so treatment focuses on protecting the injury and managing pain. Rest is the cornerstone. Reducing weight bearing on the affected bone, especially in the first several weeks, gives the trabecular tissue a chance to repair without further compression.
Ice and over-the-counter anti-inflammatory medications can help with pain and swelling in the early stages. Your doctor may recommend crutches, a brace, or a walking boot depending on the location and severity. For athletes, a gradual return to activity is important. Jumping back into high-impact exercise while the bone is still healing risks converting a bruise into a stress fracture.
Most people don’t need any procedure or intervention beyond time and activity modification. The key is patience. Because the injury is invisible on the outside, it’s tempting to push through the pain, but the internal damage is real and needs adequate time to resolve.
Potential Complications
Most bone bruises heal completely without lasting problems. In rare cases, however, severe or repeated bone bruises can damage the blood supply to a section of bone, leading to a condition called avascular necrosis, where bone tissue dies from lack of blood flow. This risk is highest near joints like the hip, knee, and shoulder, where the blood supply is already limited. Over time, the dead bone can weaken and eventually collapse, causing joint damage.
Bone bruises near joint surfaces also raise concerns about cartilage. When the spongy bone just beneath the cartilage is injured, the cartilage above it can lose its structural support. In some cases, this contributes to long-term joint pain or accelerates wear over time. This is one reason doctors take bone bruises seriously even though they don’t show up on X-rays. The injury may be hidden, but it can have real consequences if not given enough time to heal.