What on Earth is a bone bruise? We’re all familiar with a bruise on the skin, or a muscle bruise (known as a cork or contusion) which is bleeding from an injury. The injury is usually a direct impact or blow which ruptures cells and small blood vessels causing bleeding and swelling. In some joint injuries such as spraining your ankle or knee, not only are the ligaments damaged but quite often a bone bruise occurs. The bone bruise is a bone injury and is painful over and above the pain of your ligament injury. A bone bruise happens in about 70% of people who injure the ACL (anterior cruciate ligament) in the knee, and in 10% to 40% of ankle sprains. In a high ankle (syndesmosis) injury around 78% of people sustain a bone bruise (see our post on syndesmosis injures here). Often the articular cartilage is also damaged (ie the cartilage covering the bone that was bruised), which can lead to osteoarthritis at a later date. All of these injuries mean that early assessment and world class care are helpful in minimising or preventing long term issues.
A bone bruise or “contusion” is an injury to the bone that occurs due to the impact and shear forces that tore the ligament. It is only seen on an MRI and doesn’t show up on plain Xray or CT scan. It is bleeding and swelling (ie a bruise) within the bone due to microfracture of the trabecular bone (this is the part of the bone that looks a bit like a lattice and contains marrow). Microfracture – that means a small part of the bone was broken, not enough to show on Xray but enough to really slow you down with impact loading such as running.
Bone bruises are one reason why I refer all high grade ankle and knee injuries for MRI in the first week. The reasons I do this straight away is that MRI is far more accurate when performed straight after your injury, it assists comprehensive and accurate EARLY diagnosis which is essential for world class management, and it ensures that my advice to you is based on all of the injuries you have sustained and in so doing your treatment is tailored specifically for your individual circumstance.
Another reason to diagnose early is that bone bruises are painful and require a delay in return to running or sport. The bone has a rich nerve supply, as anyone who has ever broken a bone can testify. The pain serves a very useful protective function, limiting your ability to run after the injury until such time as the bone and ligament heal. The bone bruise itself simply requires unloading (using a moon boot and crutches) to heal. Healing time varies between 6 weeks to 2 years depending on exactly what you have done (you don’t usually need the boot and crutches for more than 2-6 weeks of this period). As a rough guide most sports people can begin running between 6 weeks and 6 months after an ankle bone bruise depending on its location and how extensive it is.
Although a bone bruise will heal with time and unloading, the associated ligament damage, joint stiffness, weakness, poor proprioception (balance / reflexes) and range of motion all need treatment. This treatment aims to prevent scar tissue blocking movement, and to get you back to sport at the same level as before your injury. These things are important to manage to minimise the risk of long term pain and damage. If you are worried about not being in your sport for some weeks or even months, as Sports & Musculoskeletal Physiotherapist I can advise you on other ways to maintain your cardiovascular fitness and strength that won’t injure your damaged joint and aggravate the bone pain from a bone bruise. If done well, this period can see you develop strength in some areas to a far higher level than you’ve done before, simply because you didn’t have enough time with the rest of your training and work commitments.