Background/Purpose: Unlike fragility fractures, high-trauma and insufficiency fractures (IF) are not classically considered osteoporotic fractures. Patients with rheumatic and musculoskeletal diseases (RMD), especially those with rheumatoid arthritis (RA), are at increased risk of IF due to factors associated with reduced bone quality including chronic inflammation, medication, and altered biomechanics. IF frequently occur in ankle joints and feet. These fractures are often not detected in conventional radiographs, magnetic resonance imaging (MRI) is thought to be more sensitive.

The aim of this study was (i) to determine the frequency of IF in symptomatic ankles and feet of patients presenting to a tertiary hospital, to (ii) identify possible risk factors and (iii) to compare the IF detection rate of radiographs and MRI.

Methods: Using a retrospective study design, data of patients who had undergone MRI scans of the ankle/foot region between 2016 and 2018 were analyzed. Patients with IF were matched with 2 control subjects based on sex, age, and diagnosis and pertinent data was extracted from their medical records. Statistical analyses included T tests, chi-square tests, and regression analyses.

Results: In a total of 1471 foot and 281 ankle joint MRIs, 129 (7.4%) IF were detected. The mean age of patients with IF was 59 years, 82.9% were women. Among patients with IF 80,6% had a chronic inflammatory rheumatic disease (CIRD) which was significantly more frequent than non-CIRD diseases (19,4%, p< 0,001). Potential risk factors for IF were: low bone density indicative of osteoporosis (IF 42.6% vs. controls 16.2%, p< 0.001), history of previous fracture (34.9% vs. 8.6%, p< 0.001), smoking (37.3% vs. 23.1%, p=0.005) and current methotrexate (MTX) therapy (42.6% vs. 27.9%, p=0.005). Of the 96 (74.4%) IF patients who also had x-rays of the ankle/foot region, 24 (25%) had an IF diagnosis in the x-ray report.

Conclusion: With a frequency of 7.4%, IF are a relatively common cause of foot/ankle pain in patients with RMD who underwent MRI after presenting to a tertiary rheumatology hospital. Risk factors for IF largely corresponded to established risk factors for osteoporosis. The potential negative influence of MTX needs further research. Future studies should investigate whether the occurrence of IF represents an indication for anti-osteoporotic therapy and whether such treatment improves fracture healing and lowers the risk of future fractures.

Patient demographics BMI – body mass index, RA – rheumatoid arthritis, PsoA – psoriatic arthritis, CIRD – chronic inflammatory rheumatic disease, MTX – methotraxate

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/prevalence-and-risk-factors-of-insufficiency-fractures-of-the-foot-and-ankle-joint-in-rheumatic-and-musculoskeletal-diseases/