ssociations Between Calcaneal Enthesophytes and Osteoarthritis of the Hands and Feet.

OBJECTIVE: To examine associations between calcaneal enthesophytes and osteoarthritis (OA) in the hands and feet, and to provide insights into the role of biomechanical and systemic processes in the development of OA. METHODS: Adults ages ≥50 years who were registered with 4 general practices were mailed a Health Survey. Responders reporting foot pain within the last 12 months underwent a detailed assessment, including hand and foot radiographs. Calcaneal enthesophytes (plantar and posterior) and OA features (osteophytes and joint space narrowing) were documented. Associations between enthesophytes and hand and foot OA (including OA phenotypes and OA features at individual joints) were explored using generalized estimating equations, adjusting for age, sex, and body mass index. RESULTS: Data were available from 532 participants (298 women, mean ± SD age 64.9 ± 8.4 years). Calcaneal enthesophytes were not associated with hand OA phenotypes or OA at individual hand joints. In contrast, plantar calcaneal enthesophytes were positively associated with polyarticular foot OA (odds ratio [OR] 1.80 [95% confidence interval (95% CI) 1.02-3.17]). When individual foot joints were examined, posterior enthesophytes were associated with talonavicular joint OA (OR 1.58 [95% CI 1.02-2.44]) and plantar enthesophytes were associated with first metatarsophalangeal joint OA (OR 0.67 [95% CI 0.49-0.98]) and navicular-cuneiform joint OA (OR 2.30 [95% CI 1.40-3.79]). Patterns of association were similar for osteophytes and joint space narrowing. CONCLUSION: Calcaneal enthesophytes are associated with foot OA but not hand OA. The pattern of association is indicative of a local, biomechanical rather than systemic bone-forming process.