A 27-year-old woman complains of pain and morning stiffness in the small joints of her hands. Her condition is weather-dependent. Objectively, she presents with swelling and deformation of her proximal interphalangeal joints and her second and third metacarpophalangeal joints. X-ray of the hands detects bone erosions (usurations) and signs of osteoporosis. What is the most likely diagnosis in this case?