Bone Bruises in the Knee (Bone Contusions)

Introduction

A bone bruise, also called a bone contusion, is an injury to the surface of a bone that is less severe than a fracture but still painful. In the knee, bone bruises often occur after a hard impact, such as falling directly onto the knee, twisting the joint, or during sports injuries like a collision or awkward landing. Imagine dropping an apple on a hard floor. A localized “bruise” often occurs where it lands. This is akin to a bone bruise in the knee. They commonly occur as part of an anterior cruciate ligament (ACL) injury. When a bone contusion occurs in the knee, small areas inside the bone become damaged and can bleed or swell. Symptoms usually include knee pain, swelling, stiffness, and difficulty putting weight on the joint.

What Causes a Bone Bruise

Bone bruises in the knee happen when the bone is compressed or struck with enough force to cause microscopic fractures to the bone and damage to the tiny blood vessels. This leads to localized bleeding. Bone contusions are particularly common in the setting of other serious knee injuries. It has been noted that 70-80 percent of ACL injuries are associated with a bone bruise. Bone bruises in the knee commonly occur in the round weight-bearing part of the upper bone that makes up the knee joint (the femoral condyle) or the outside part of the lower bone of the knee joint (lateral tibial plateau). This bleeding and swelling within the bone make it less able to absorb shock, which can cause ongoing pain. Because the knee is a weight-bearing joint, a bone bruise can make everyday activities like walking, climbing stairs, or exercising uncomfortable. In some cases, bone bruises are seen alongside other knee injuries, such as ligament tears or cartilage damage, which can make the symptoms worse.

How is a Bone Bruise in the Knee Diagnosed?

To diagnose a bone bruise in the knee, a doctor will begin by asking about the injury and the symptoms. They will examine the knee, checking for swelling, tenderness, range of motion, and signs of other knee injuries (ex. ACL tears, MCL strains, meniscal tears, etc). Standard X-rays are often taken to make sure the bone is not broken, but X-rays cannot show bone bruises. The most useful imaging test is an MRI, which can reveal the bleeding and swelling inside the bone and help the doctor determine how severe the injury is.

Treatment of a Bone Bruise in the Knee

Treatment for an isolated bone bruise affecting the knee usually does not involve surgery. Instead, rest, ice, compression, and elevation (the RICE method) are recommended in the early stages to reduce swelling and pain. Using crutches or a brace may be helpful to limit weight on the knee while the microscopic injury to the bone heals. Over-the-counter pain medicine such as acetaminophen or anti-inflammatory medication can also provide relief. Recovery can take several weeks to months, depending on how severe the bruise is. Most bone bruises heal completely with time, but in some cases, severe bruises can lead to long-term knee stiffness or even damage to the bone or cartilage if not properly managed.

Edited by Stephen Pinney MD, September 20th 2025.