Myositis Ossificans

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 How did it occur? When did it occur? What type of pain do you have? Does the pain change at different times? Is there any other sensation rather than pain? Is there any swelling? If so, was swelling immediate or did it come later?      Observation   Look at how the athlete moves. Look for swelling, contusion, and ecchymosis. Check for a palpable mass within the muscle. Mass usually shows up within 2-3 weeks.

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 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 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 _____. immediately never 4-6 weeks 2-3 weeks

Questions 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