Bone Bruise in the Knee: What It Means on Your MRI

What is a bone bruise?

Bone is not solid all the way through. Inside the hard outer shell is a honeycomb of fine bone struts filled with marrow. A strong impact can cause tiny breaks in those struts with bleeding and swelling inside the bone, without a visible fracture line. This is a bone bruise, also called a bone contusion or, on an MRI report, bone marrow oedema.

Bone bruises do not show on ordinary X-rays. They are found on MRI, often when the scan is done to check for ligament or meniscus damage.

Symptoms in patients' own words

• "It's a deep ache inside the knee, not on the skin"
• "It hurts when I put weight on it or go down stairs"
• "The knee swelled after I twisted it"
• "It throbs at night after a busy day"
• "There's one spot on the bone that's really tender"

Symptoms are often worse than people expect for an injury that does not show on X-ray, and they can linger after the swelling has gone.

Causes and what the pattern tells us

The location of a bone bruise on MRI is a clue to how the knee was injured.

• A twisting injury that tears the ACL often leaves matching bruises on the outer thigh bone and the back of the outer shin bone, where they knocked together as the knee shifted
• A kneecap dislocation often leaves bruises on the inner kneecap and the outer thigh bone
• A direct blow, such as a fall onto the knee or a dashboard injury in a car accident, leaves a bruise where it struck
• Hard landings from jumps can bruise the weight-bearing surfaces

In Qatar we commonly see bone bruises after football and padel twists, basketball landings, falls in the gym and road accidents. Bone marrow oedema can also appear without a clear injury, in osteoarthritis, after overuse, or with a small insufficiency fracture in older adults, so the story and examination matter.

Diagnosis

Dr. Gelber examines the knee for swelling, tenderness and ligament stability, and reviews your MRI himself rather than relying only on the report. The key questions are whether there is an associated ACL, meniscus, collateral ligament or cartilage injury, and whether the cartilage over the bruise is intact. X-rays may be taken to rule out a fracture. If the bruise has no clear injury behind it, blood tests including vitamin D and bone health may be considered.

Treatment

An isolated bone bruise is treated without surgery. The bone needs time and a manageable load to heal.

• Relative rest and activity modification, avoiding running, jumping and twisting while it is painful
• Crutches for a short period if walking is painful, then gradual return to full weight
• Ice and anti-inflammatory or pain medicines when suitable for you
• Physiotherapy to maintain movement and rebuild muscle strength
• Low-impact fitness such as cycling or swimming as pain allows

When the bone bruise comes with a torn ligament or meniscus, the treatment plan is shaped by that injury. Surgery, such as ACL reconstruction or meniscus repair, is for the associated damage, not for the bruise itself. A large bruise is one of the reasons the knee is sometimes allowed to settle before surgery.

Recovery and return to sport

Pain from a bone bruise usually settles over several weeks, while the changes on MRI can take a few months or longer to fade. Return to running and sport is guided by symptoms: walking without a limp, no pain with daily activities, full movement and good strength. Pushing back to football or padel too early can prolong the pain.

A severe bone bruise can be a marker of significant impact to the cartilage, so a few patients develop cartilage problems later. Follow-up is advised if pain persists.

When to see a specialist in Doha

See a knee specialist if your knee swelled after an injury, if you cannot put full weight on it, if it gives way or locks, or if an MRI mentions bone bruising alongside other findings. Seek urgent care if you cannot bear weight at all, the knee looks deformed, or the leg below is numb or cold. Dr. Gelber sees knee injuries at Aman Hospital in Doha.