Young athletes commonly accumulate excess fluid in the bone marrow around the joint that connects the spine with the pelvis, according to researchers.
This research, published recently in Arthritis & Rheumatology, may help define what amount of fluid detected on imaging tests may be considered “background noise” among physically active young athletes, compared with those who have axial spondyloarthropathy (axial Spa), and inflammatory disease, which includes low back pain as its main symptom.
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, explains a media release from Wiley.
In the study, Ulrich Weber, MD, a researcher at King Christian 10th Hospital for Rheumatic Diseases in Gråsten, Denmark, and his colleagues conducted a study of 20 recreational runners and 22 professional ice hockey players to determine the frequency of bone marrow edema and its distribution across eight regions of the sacroiliac joint.
The runners received MRI scans of their sacroiliac joints before and 24 hours after a 6.2-km competitive run, and the hockey players received scans at the end of their competitive season.
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, the release explains.
“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,” Weber says.
“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 adds.
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, the release concludes.
[Source(s): Wiley, Science Daily]