Bone Abstracts

A 20-year-old male presented following a fall down. He was diagnosed with a C5–C7 burst fracture and underwent a cervical fixation surgery. He was transferred to inpatient rehabilitation with C6 ASIA A tetraplegia.

70 days after the operation, he began to have intermittent mild fever with a temperature of 37.4 ^oC. On postoperative day 72, left thigh was noted to be edematous. The circumferential difference between the lower extremities measured at 10 cm above the knee was 5 cm. CT chest thromboembolism demonstrated no evidence suggesting deep vein thrombosis. A thigh contrast MRI showed intramuscular fluid collections that appeared hyperintense on T2WI. Diffusely increased signal intensity on T2WI was noted in left iliacus, iliopsoas, vastus medialis and intermedius, gluteus medius and minimus, part of vastus lateralis. This finding suggested myositis or less like infection. At bone scan, there were uptake signals on left femur, great trochanter. And ALP was 80 IU/l and calcium was 8.9 mg/dl (after 20 days from initial, calcium level was within normal limit, but ALP was increased at 190). There were no other conditions triggered inflammatory reactions. NSAIDs and etidronate were used for 2 weeks. Although fever subsided and inflammatory markers normalized, the swelling and limitation of motion persisted. On follow-up X-ray two weeks after the initial, there were no calcified lesions. Seven weeks after initial, at the follow-up bone scan, there were high uptake signals on left femur, great trochanter. ALP was 391 and X-ray at this time, there was no calcified lesion.

When patients present with numerous medical comorbidities predisposing them to infectious conditions, immature myositis ossificans can be extremely difficult to distinguish from deep infections such as pyomyositis, cellulitis and osteomyelitis. In the case of after neurogenic and traumatic insults which include brain injury and spinal cord injury, we should suspect myositis ossificans and should not miss that treatment of choice is NSAIDs, not the antibiotics.