A bone bruise is often utilized by doctors but many individuals find the term confusing and wonder what it means to have one. Even today, there is controversy on what exactly a bone bruise is and why they occur. Before the use of MRI, there was no form of testing for a bone bruise and this is why the condition was not recognized well.
When MRI was being used, the doctors were able to find an abnormality in the bone that was described as a bone bruise. It is important to note that a bone bruise is believed to occur when there are microscopic fractures on the internal bone structure. Even though these micro-fractures do not significantly weaken the bone, it can cause inflammation and bleeding within the bone. This results to pain and symptoms similar to a soft tissue bruise. The doctors name this finding on an MRI result as bone marrow edema.
Causes of a bone bruise
- Trauma is considered as the common cause of a bone bruise. The trauma can be caused by an acute injury or repetitive overuse. One of the common causes of a bone bruise on a knee MRI is a ligament injury such as an ACL tear. Once the ACL is torn, the bones abruptly shift which causes a compression injury and a specific pattern of a bone bruise.
- Arthritis can cause damage to the cartilage surface of the joint. The protective surface helps protect and cushion the underlying bone. Once the cartilage surface is damaged or worn out, the bone might be exposed to higher stress and might succumb to the increased load. Individuals with arthritis often have bone bruises in areas typically affected by the condition.
- Osteonecrosis is a specific condition that causes disruption of the blood supply to the bone. The lack of blood can lead to the weakening of the bone. In case the bone weakens, it might sustain micro-fractures due to the lack of strength of the bone structure. Take note that these micro-fractures can cause a bone bruise surrounding the area of osteonecrosis.
Treatment of a bone bruise
The damaged bone should be allowed to rest. Once a bone bruise is present on an MRI, the bone is damaged and must be allowed to heal. It can be hard to predict how long the bruise will resolve and there are conditions in which the bone bruise can persist. A bone bruise after an ACL tear can be present for several months after the injury. As for bone bruising of osteonecrosis or arthritis, it can persist as long as these conditions are present.
In most cases, the individual is instructed to limit activity if a bone bruise is found around a joint. This is due to the concern about damage to the joint cartilage. Further damage to the bone that supports the cartilage can lead to post-traumatic arthritis. Remember that the doctor will advise the individual to allow the symptoms to fully resolve before he/she can resume any activity or sports.