Date: Monday, November 6, 2017
Session Type: ACR Concurrent Abstract Session
Session Time: 2:30PM-4:00PM
Background/Purpose: Low grade bone marrow edema (BME) was reported in the sacroiliac joints (SIJ) of up to 25% of healthy individuals and mechanical back pain patients, challenging the imaging discrimination from early spondyloarthritis (SpA) . Potential explanations range from mechanical stress lesions to vascular signals and anatomical SIJ variants. There is little evidence as to whether physical strain, e.g. sports, heavy labour work, or multiparity may trigger SIJ BME. The goal of this study was to determine BME frequency and anatomical distribution in 8 SIJ regions in hobby and professional athletes.
Methods: The sample consisted of 2 cohorts of 20 healthy hobby runners (HR) before and after running and 22 professional ice hockey players (IP) from the Danish premier league: HR/IP 40%/100% men; mean age (SD) 27.2 (5.4)/25.9 (4.6) years; mean BMI (SD) 22.6 (1.5)/25.7 (1.6) kg/m2. Semicoronal MRI scans of the SIJ with T1SE and STIR sequences were obtained in HR before and 24 hours after a running competition over 6.2 km (mean duration 35.4 minutes, mean speed 10.4 km/h), and in IP at the end of the competitive season. The scans were assessed for BME independently by 3 blinded readers (AGJ, AZ, UW) according to the quadrant based MORPHO module (www.carearthritis.com). Paired images of HR were read blinded to timepoint. 7 MRI scans (2 paired images) of SpA patients under TNF treatment served to mask readers. A pre-test reader calibration used MRI scans from 11 patients with active sacroiliitis and 9 healthy volunteers. Reader agreement was assessed by ICC (3, 1). Descriptive analysis comprised mean frequency of SIJ quadrants with BME and their distribution in 8 anatomical SIJ regions: upper/lower ilium and sacrum, subdivided in anterior and posterior slices, as concordantly recorded by the majority (≥2/3) of readers.
Results: Agreement among 3 readers for SIJ BME was excellent in calibration (ICC 0.93) and moderate in athletes (ICC 0.59) due to low frequency of BME. The mean number (SD) of SIJ quadrants showing BME was 3.1 (4.2)/3.1 (4.5) in HR before/after running, and 3.6 (3.0) in IP. The posterior lower ilium was the single most affected region, followed by the anterior upper sacrum, consistently across 2 cohorts of athletes.
Table 1. Frequency and anatomical distribution of SIJ quadrants with BME in 2 cohorts of athletes. Abbreviations. n (%) with ≥1/2/3/4 SIJ Q: number of subjects (%) with ≥1/2/3/4 SIJ quadrants with BME as reported by ≥2/3 readers.
In hobby and professional athletes, BME showed on average in 3-4 SIJ quadrants. The posterior lower ilium was the single most affected SIJ region, followed by the anterior upper sacrum. These findings in healthy controls help refine thresholds for a positive SIJ MRI in early SpA.
References.  Weber U et al. Curr Rheumatol Rep 2016;18:58.
To cite this abstract in AMA style:Weber U, Jurik AG, Zejden A, Larsen E, Jørgensen SH, Rufibach K, Schioldan C, Schmidt-Olsen S. Bone Marrow Edema in Sacroiliac Joints of Young Athletes Is Common and Shows Most Frequently in the Posterior Lower Ilium [abstract]. Arthritis Rheumatol. 2017; 69 (suppl 10). https://acrabstracts.org/abstract/bone-marrow-edema-in-sacroiliac-joints-of-young-athletes-is-common-and-shows-most-frequently-in-the-posterior-lower-ilium/. Accessed September 24, 2021.
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