Some medical conditions can cause symptoms similar to osteoarthritis.

Most common

• Injuries (such as bursitis/tendinopathy, strains, or sprains) to the tissues around the joints (such as ligaments or tendons). These may occur from overuse of the joint or from a physical injury.
• Fibromyalgia
• Polymyalgia rheumatica
• Gout or pseudogout
• Low back pain

Less common

• Rheumatoid arthritis
• Psoriatic arthritis
• Spine fractures due to bone weakening/thinning (osteoporosis)
• Poor blood circulation in the legs (peripheral arterial disease)

Uncommon

• Systemic lupus erythematosus (lupus, or SLE)
• Septic arthritis
• Lyme disease
• Blood clot in the veins

Rare

• Pain caused by cancer that has spread to the bones
• Ankylosing spondylitis