A 27-year-old male presents with hip and sacroiliac joint pain for 6 months, which improves with activity. One month ago, he developed left knee joint swelling and pain. The most likely diagnosis is:
A 27-year-old male presents with hip and sacroiliac joint pain for 6 months, which improves with activity. One month ago, he developed left knee joint swelling and pain. The most likely diagnosis is: