• CBD Wellness Centre

Myositis Ossificans

Hi everyone and welcome to this week’s blog topic! Today we are going to discuss myositis ossificans (MO). With the winter sport season now in full swing we thought it would be a good idea to provide an insight into what this condition is, how it occurs and how to minimise its prevalence.


What is MO?

MO is a condition in which bone forms inside soft tissue structures, most commonly muscle. It is typically caused by a single direct trauma to a muscle that results in a deep muscle contusion and hematoma growth (AKA: a ‘corky’ or ‘charlie horse’). It can also occur following repeated muscular trauma to the same spot, or, rarely, by a bad muscle strain. Examples include a heavy knock to the thigh in a game of football or landing heavily in a cycling accident. MO can further develop from repetitive minor trauma such as the bumping experienced during horse riding, or recoil when shooting.


How Does MO Develop?

Occasionally after a contusion the resultant hematoma will calcify (turn to bone). Whilst the exact mechanism remains unclear it appears that the body makes an error in the healing process. When a skeletal muscle is injured, inflammatory cytokines are released. These cytokines stimulate cells in the blood vessels to transform into mesenchymal stem cells to repair the damaged tissue, in muscles these are known as fibroblasts.



In the case of MO, inappropriate response of stem cells causes differentiation of these fibroblasts into osteogenic (bone) cells resulting in immature bone formation within the healing soft tissues. This gradually occurs about 2-3 weeks after the initial injury and ceases around the 6-7 week mark. At this stage a lump is often palpable, may become painful and can restrict movement in the affected muscle. Slow resorption of the boney deposit does occur, but often a small amount remains.



Why some contusions develop calcification is not known, however the more severe the contusion (i.e. increased bleeding) the more likely the development of MO. It can occur in people who participate in sport at all levels, from social participants to highly competitive or professional athletes. It can be hard to predict who will get myositis ossificans, but the condition appears to be more prevalent in active young adults and athletes.


What are the Symptoms of MO?

Most contusions, strains, and hematomas will start to improve within a few days or weeks if the RICE Regime is being followed. But people with MO development will notice that their pain worsens, and range of movement reduces. Other symptoms can include:

· Swelling and feeling of warmth in the area

· May be able to feel a palpable lump in the muscle

· Severe pain and tenderness – limited to the injured muscle

· An increase in morning pain and with activity


How is MO Treated?

MO is usually a self-resolving condition and hence it tends to respond well to conservative treatment. In the first 24-72 hours you need to be careful not to aggravate the bleeding by excessive activity, alcohol intake or the application of heat or massage (avoid Heat, Alcohol, Running, Massage (HARM)). Hence aggressive muscle therapy must be avoided during this time. During this phase it is important to follow the RICE regime to minimize the size of the hematoma and subsequent risk of developing MO in the first place.


· R – Rest à avoid loading the injured area, use crutches

if weight bearing is painful

· I – Ice à limits bleeding in the area and acts a natural

painkiller by sending the area numb

· C – Compression à perhaps the most important step,

the muscle should be compressed and iced in the

position of maximal pain free stretch.

· E -- Elevation à elevate the injured limb above the

level of the heart to minimize blood flow (swelling)

and encourage drainage of the injured area


Taking pain relievers can further help relieve discomfort. After the first 48 to 72 hours, a person can consult their health care practitioner to begin the rehab process. This will consist of electrotherapy (pulsed ultrasound), gentle ROM exercises, stretching and strengthening exercises to help decrease the size of the bony-tissue deposit.


Light stretching of the injured muscle is highly encouraged. While the stretching shouldn't be painful, the continued use of the muscle helps keep your range of motion from being affected and MO is more likely to develop in a sedentary muscle, so keeping it moving is imperative.

If pain relievers and physical therapy are not effective in treating myositis ossificans, surgical removal of the growth may be needed. Surgery is usually only considered in cases that have continued severe pain, growths that interfere with nearby nerves, joints, or blood vessels or poor range of motion that makes it difficult to perform daily activities. Surgery is only performed after 6 to 18 months once the deposit has matured. If surgery is performed too early, it may predispose to recurrence.


Can I prevent MO?

The best way to minimise the risk of MO is to avoid deep trauma to the muscles. If you engage in high contact sports or activities make sure you are wearing the appropriate protective equipment this may include:

· knee pads and shin gaurds

· Padded bike shorts (basketball and football)

· Shoulder or jacket padding (motorsports)

· Tape padding to areas susceptible to recurrent contact.



If contact can’t be avoided, then it’s important to treat contusions with particular care as inappropriate early intervention including heat or massage may increase the risk of MO arising.

In the acute phases of any contusion heavy loading of the affected muscle(s), massage and excessive stretching should be avoided to avoid aggravation. You may be able to prevent MO by properly taking care of your injury in the first two weeks. Achieve this by following the RICE regime, and engaging in gentle, pain free, stretching and ROM exercises à MO is more likely to affect a muscle that is not being used.


So that’s a brief overview of what Myositis Ossificans is and how it occurs. If you have questions or comments, feel free to e-mail us at admin@cbdwellnesscentre.com.au and we will happily answer them for you.


If you are suffering with the symptoms mentioned in this blog, call us on (08) 9486 8653 and we will arrange an assessment for you.

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