Musculoskeletal clinical case of the month – Myositis Ossificans

Myositis Ossificans (MO)

Myositis Ossificans is a complication that can occur after muscle injury, and is particularly prevalent in the athletic population and young adults. It is characterised by abnormal calcification/bone growth in healing muscle after injury and usually occurs in the larger muscle groups. Sports whose participants are particularly susceptible to developing MO include;

  • contact sports where muscle contusion is common (e.g. rugby)
  • sports that involve high velocity running (e.g. sprinting) where muscle tears are common

Myositis Ossificans is the most common form of Heterophic Ossification, the umbrella diagnosis for a group of conditions where there is formation of extraskeletal bone in soft tissues.

Clinical Presentation

  • 46-year-old man
  • Avid marathon runner
  • Blunt trauma to left anterior thigh from fall on stairs 1 week ago
  • DH – Nil anticoagulants. Nil else.
  • PMH – Nil of note
  • FH – Nil of note
  • Examination left thigh
    • Difficulty walking
    • Large tense swelling
    • No bruising
    • Restricted range of knee flexion to 100 degrees
  • Ultrasound in clinic demonstrated;
    • Vastus Intermedius liquified haematoma
    • No other muscle injury
  • Patient had 60mls blood drained from haematoma on the same day and sent home with compression on thigh

Further injury and investigation

  • Patient unfortunately sustained re-injury to quadriceps whilst walking the dog which resulted in fresh re-bleed and new calcification formation
  • Range of knee flexion reduced further and now unable to flex beyond 80 degrees
  • Repeat ultrasound and MRI show development of myositis ossificans in Vastus Intermedius


  • Top left – Preliminary Ultrasound showing haematoma pre-drainage
  • Top right – Repeat Ultrasound after re-injury showing initial calcification deposits
  • Bottom left – MRI after re-injury confirming location of deposits in VI
  • Bottom right – X-ray thigh 2 months later showing mild resultant calcification
  • MO collage-1
mo Musculoskeletal clinical case of the month - Myositis Ossificans

Management post re-injury


  • Patient started on Indomethacin 200mg daily immediately, taken for 2 weeks total
  • New haematoma not amenable for repeat drainage as not liquified and increased risk of infection


  • First 48 hours post-re-injury
    • Tight compression throughout the length of the thigh
    • Offload on crutches
  • First 2 weeks
    • Partial weight-bearing
    • Quadricep length focused on in initial stages with passive prone knee bends
    • Quadricep muscle activation using isometric squeeze exercises
    • Muscle stimulation via compex
    • Pool based activity and stretches
    • Ongoing daily compression
  • Weeks 2-4
    • Return to normal walking unaided
    • Gym based rehab with concentric and eccentric quadriceps, gluteal and hamstring activation
    • Restoration of injured thigh muscle length (including hamstrings)
  • Weeks 4-6
    • Light jogging and continuation of strength and flexibility work
    • Week 8 return to running

Key learning points – Myositis Ossificans

  • Myositis Ossificans is a common condition in active people who exercise and are more susceptible to soft tissue injury
  • It occurs when soft tissue bruising and haematoma, results in calcific deposits
  • Recurrent muscle injury/bruising/haematoma increases the risk of MO
  • It is more common in larger muscle groups e.g. quadriceps, hamstrings
  • It is a radiology ‘DO NOT TOUCH’ lesion, i.e. should be diagnosed directly from x-ray or MRI
  • This is to avoid unnecessary surgical intervention. Biopsy at early stage may be indistinguishable from Sarcoma.
  • Investigation; X-ray is gold standard for detecting MO
  • Management;
    • No clear consensus on how to treat
    • Reducing soft tissue swelling, bruising, haematoma collection can help prevent formation e.g. compression, drainage of fluid
    • Indomethacin commonly used by sports medicine medical prescribers for a period of 2 weeks to prevent calcification
    • Once calcification is present, babotage and shockwave can help break down deposits and improve function
    • Novel therapies such as acetic acid solution administered via iontophoresis have mixed evidence
    • Surgical intervention may prompt further MO development
  • Rehabilitation;
    • Goal is to regain as much range of movement and strength ASAP.
    • Manual therapy and deep soft tissue around MO needs to be done with caution to prevent further spread
    • Normal functionality of muscle can be achieved despite large MO deposits
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