Elite young athletes are prone to the accumulation of excess fluid in the bone marrow around the joint also known as bone marrow edema, finds a new study. The findings of this study are published in the Journal of Arthritis & Rheumatology.
The research was conducted to improve the diagnosis of axial Spa, which most commonly affects people in their teens and 20s, especially young men. Bone marrow edema, or the accumulation of excess fluid in bone marrow, in the sacroiliac joint is an inflammatory process thought to play a major role in the disease.
Magnetic resonance imaging (MRI) can detect bone marrow edema and structural changes in the sacroiliac joint when patients begin to experience pain, but there is an ongoing debate about what constitutes a positive MRI for the diagnosis of axial SpA early in the course of the disease.
The average number of sacroiliac joint quadrants showing bone marrow edema in the healthy runners was 3.1 before and after running, and 3.6 in the hockey players. The posterior lower ilium was the most affected region, followed by the anterior upper sacrum.
"Our study in individuals experiencing a broad span of mechanical strain intensity to the axial skeleton contributes several issues to refine a definition of about what constitutes a positive lesion signature on sacroiliac joint MRI," said Dr. Weber.
"Limited specificity of sacroiliac joint bone marrow edema is highlighted by the study finding that one out of three healthy athletes would meet the currently most widely applied classification criteria for SpA based solely on bone marrow edema. This has impacts concerning where to set the threshold for between normal variation and disease." Dr. Weber noted that the finding that edema occurs in two anatomical regions of the sacroiliac joint in healthy individuals is also noteworthy.
"The presence of solely low-grade bone marrow edema, particularly if clustered in the posterior lower ilium or anterior upper sacrum, may not be sufficient to confirm axial SpA," he said. The study did not reveal any relevant structural changes in the sacroiliac joints of healthy individuals, despite high mechanical axial strain from their sport. Therefore, structural changes such as erosion may be key for discriminating disease from normal variations.