As a Spine Specialist, I commonly see patients with Spine issues misdiagnosed as Knee osteoarthritis and also knee problems wrongly diagnosed as spine issue What is required is to be physically examined by a Spine specialist, since we are trained in Orthopaedics and then further trained to deal with all Spine problems as well Hope you get the right expert and Wishing you a speedy recovery

It’s suggestive of Lumbar spine sciatica type of pain and not osteoarthritis

Get xray of lumber spine

It can be because of spondylitis in back also. Take some muscle relaxant medication Heating pads Physiotherapy sessions