Likely arthritis or multi-system disease such as lupus. Rheumatologic evaluation essential.
It really could be any number of things from inflammatory (arthritis) to a ligamentous injury. I would start by seeing my pcp.
Prior surgery?Swelling? Fever? Med hx? Too many posibilities. Need an evaluation with xrays.
Have it evaluated:
Have it evaluated by a professional. Depending on the severity of the injury treatment options include: bracing, casting, physical therapy, injections, and surgical repair.
Have it evaluated.:
Locking and clicking are signs of soft tissue or meniscus damage. This needs to be evaluated and treated by a specialist to possibly prevent future complications.
Yes, a knee replacement is almost certainly in your future. However, 55 is on the young side for this surgery. Knee sleeves, NSAIDs and injections such as Synvisc or Orthovisc may help and should be tried first.
Is a nonspecific sign and does not indicated tears or any other pathology. However, if your pain is worsening it is important to be evaluated by a musculoskeletal physician to determine the cause and correct treatment of your knee pain.