What percentage of rheumatoid arthritis patients have subtalar joint involvement?

• A. 10-20%
• B. 30-40%
• C. 50-60%
• D. 70-80%

Answer: (B)

The key idea is recognizing how often the subtalar joint is affected in rheumatoid arthritis. In RA, multiple joints can be involved, but involvement of the subtalar joint specifically occurs in about 30-40% of patients. This makes 30-40% the best estimate because it reflects a substantial minority—not the majority—of RA patients who have hindfoot involvement. Clinically, subtalar involvement can contribute to hindfoot pain, deformity such as valgus alignment, and mobility issues, and it may be detected on imaging even when symptoms aren’t dramatic. The other percentages overstate or understate how commonly the subtalar joint is involved in RA, which is why the 30-40% range is the most accurate reflection.