Myositis Ossificans

Myositis ossificans results from a complication of
a contusion injury and occurs when part of of the
hematoma is replaced with bone. This condition
can occur anywhere in the body but more
commonly occurs in the quadriceps.
 The bone deposits may occur as a separate piece
or pieces of bone lying entirely within the muscle
or attached to the bone (exostosis).
Myositis Ossificans

These calcium deposits are thought to be
caused by periosteal cells that invade the
hematoma following the injury.
 This causes a partial avulsion of muscle
fibers from the periosteum.
Mechanism of Injury and
Presentation

Usually caused by injuries that result in a severe
contusion or chronic contusion injuries.
 Patient will first present with severe pain at first
usually with a contusion and a palpable mass
within the muscle.
Signs and Symptoms

Bruising
Pain
Palpable mass
in muscle
Examination and
Evaluation





History
•
Observation
How did it occur?
Look at how the athlete
moves.
When did it occur?
• Look for swelling,
What type of pain do you
contusion, and
have?
ecchymosis.
Does the pain change at
different times?
Is there any other sensation • Check for a palpable mass
within the muscle. Mass
rather than pain?
usually shows up within
Is there any swelling? If
2-3 weeks.
so, was swelling immediate
or did it come later?
Examination and Evaluation
Palpation

Palpate along the
muscle and around the
contused area to feel
for a calcium deposit.
Special Test
 Manual Muscle
Testing- assess the
strength of the athlete
you are testing.
 Check Range of
Motion-check the
athlete’s range of
motion to see if
calcium deposit is
decreasing ROM.

Referral/Diagnostic Procedure

Plain Film
Radiographs

MRI
Rehabilitation and Protection

Range of Motion Exercises

Stretch

Protective covering over the injured
area.
Treatment

Heat
 Massage
 Ultrasound
* If the condition is
painful and restricts
motion, the calcium
deposit may be
removed after one
year with much less
likelihood of its return.
Too-early removal of
the formation may
cause it to return.
Questions
1.
2.
What is myositis ossificans?
a. contusion
b. calcium deposit
c. an avulsion fracture
d. inflammed muscle
Myositis ossificans is result of
a. repetitive contusions
b. severe hematoma
c. untreated contusion
d. all the above
Questions
3.
4.
Myositis ossificans is caused by ____
cells that invade a hematoma.
a. osteoblastic
b. osteoclastic
c. periosteal
d. none of the above
A palpable mass in the muscle will be
seen _____.
a.
b.
c.
d.
immediately
never
4-6 weeks
2-3 weeks
Questions
5.
Calcium deposits should only be removed
under what condition(s)?
a.condition is severely painful
b. motion is restricted
c. mass is too large
d. contusion has been resolved
Sources


Arnheim, Daniel D.& Prentice, William E. (1999) Principles of Athletic
Training. 10th edition. pg. 571. Boston: McGraw Hill Press
Bosher, James M. & Thibodeau, Gary A.(1994) Athletic Injury Assessment.
pg.520
 Larson,Christopher M. MD; Louis C. Almekinders, MD; Spero G. Karas, MD;
William E. Garrett, MD, PhD (February 2002). The Physician and
Sportsmedicine. Vol.30 No.2 “Evaluating and Managing Muscle Contusions
and Myositis Ossificans .”
http://www.physsportsmed.com/issues/2001/12_01/moeller.htm
 Prentice, William E.(2003) Therapeutic Modalities for Sports Medicine and
Athletic Training. 5th edition. pg.120-121
 Ruane, Joseph J., DO; Thomas A. Rossi, MD(April 1997). The Physician and
Sportsmedicine. Vol.26 No.4 “When Groin Pain Is More Than 'Just a Strain':
Navigating a Broad Differential”
http://www.physsportsmed.com/issues/2001/12_01/moeller.htm