A 20-year-old male player suffered an injury to his left rectus femoris while kicking a ball eight weeks ago. He was able to continue playing in the game and did not seek medical attention despite pain and swelling in the quadriceps region. He continued to practice the following week and his symptoms were improving until, without warning, he developed increased pain and swelling of the same region. On presentation he was unable to flex the knee beyond 70o, there was tenderness over 20cm of the mid-belly of the lateral quadriceps with associated swelling in this region. The strength of knee extension was maintained while his hip and knee exam were otherwise unremarkable.
X-ray of the thigh showed a linear calcification measuring up to 16mm in AP thickness proximally, at the anterior aspect of the mid to distal femoral diaphysis. An MRI showed an abnormality centred about the musculotendinous junction of the left rectus femoris. This is characterised by diffuse heterogeneous signal intensity with peripheral low T1 T2 signal which corresponds to the area of ossification seen on the x-rays. There is minor oedema seen in the muscle adjacent to the deep fascial layer but no definite fascial oedema seen.
This player was managed with an initial period of rest. He was encouraged to start a gentle quadriceps stretching programme and to avoid massage or local treatments. Unfortunately he continues to be symptomatic and limited to gentle strengthening activities off-field at the two-month mark post-injury.
These imaging findings are consistent with myositis ossificans (MO), which is a proliferation of cartilage and bone within muscle that almost always is a result of direct trauma with intramuscular hematoma. It is estimated to occur after 9 to 14 percent of muscle contusions, with higher risk following more severe contusions.
MO may form as early as four days following trauma, but can take several weeks to develop. Typical symptoms include localized pain, swelling, and decreased range of motion. Maintaining compression and stretch of the affected muscle post-trauma can help reduce the incidence of occurrence of MO, although there is a paucity of evidence showing effectiveness of this preventative approach. Maintaining knee flexion of 120o following a severe quadriceps contusion is the most widely adopted application of this preventative approach.
An MO lesion typically takes 6-12 months to fully develop. The athlete can participate in strengthening and on-field activities as their pain and function allow. Aggressive passive stretching of the affected region should be avoided. The body regularly resorbs the lesion over time. Progress can be followed with plain radiographs and surgical excision is rarely indicated.
FIFA does not bear any responsibility for the accuracy and completeness of any information provided in the “Radiology Review” features and cannot be held liable with regard to the information provided or any acts or omissions occurring on the basis of this information.