Background/Purpose: Enthesophytes consist of calcium deposition on tendons or ligaments that are proposed to form in response to localized inflammation of the enthesis, either idiopathic or in response to repetitive strain. The exact etiology of these deposits is unknown, but it has been proposed that they form as a result of tendon degeneration or a cell-mediated reactive process, and one working theory postulates that enthesophyte formation could be correlated with metabolic disorders. It is suggested that metabolic syndromes contribute to enthesopathy through tendon degeneration, aging and overuse. While joint X-ray is known to identify enthesophytes, musculoskeletal ultrasound (MSUS) offers dynamic testing due to its non-invasive nature, decreased radiation burden, affordability and versatility. There is limited research that focuses on ultrasound identification of enthesophytes in relation to metabolic syndrome and compared to other imaging modalities.

Methods: This pilot study compared the prevalence of metabolic syndrome, (characterized as hypertension, hyperlipidemia, diabetes mellitus, elevated Body Mass Index (BMI)) and enthesophytes identified on imaging between MSUS examinations and joint X-rays. The patients were identified through retrospective data collection taken from General Rheumatology Clinic and Rheumatology MSUS Clinic. 49 joints evaluated for joint pain by X-ray demonstrated enthesophytes and 5 joints evaluated for joint pain by MSUS demonstrated enthesophytes. We aimed to evaluate how many patients with joint pain found to have enthesophytes also had comorbid metabolic syndrome.

Results: Of the 49 joints demonstrating enthesophytes on X-ray, this population showed a prevalence of comorbid metabolic syndrome per joint as follows: pelvis – 17/18, knee – 9/10, and ankle – 21/21. The joint X-ray population showed evidence of enthesophytes according to age range per joint as follows: pelvis – < 40yo: 0/8, 40-70yo: 15/71, and >70yo: 3/11, knee – < 40yo: 0/8, 40-70yo: 6/71, >70yo: 4/11, and ankle – < 40yo: 0/8, 40-70yo: 16/71, and >70yo: 5/11.

Of the 5 joints demonstrating enthesophytes with MSUS, this population showed a similar prevalence of comorbid metabolic syndrome in isolated studies of the hip/pelvis (n=1), ankle (n=3).

Conclusion: As a pilot study, we found that X-ray is useful in detecting enthesophytes as a pathologic cause of pain in patients with metabolic syndrome. This highlights the need to investigate further the mechanism that drives this force. Joint X-ray showed a correlation of metabolic syndrome and age with the presence of enthesophytes. In our early MSUS evaluations, detection is achievable as well and demonstrates the high prevalence metabolic syndrome and the presence of enthesophytes, which indicates that there may be a safer, faster, more affordable way to evaluate for this underlying comorbid condition.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/association-between-metabolic-syndrome-and-the-presence-of-enthesophytes-on-musculoskeletal-ultrasound-compared-to-joint-x-ray/