Just got back from NYC and saw The Phantom one more time. The title reminded me about a question I've been considering for quite some time about total knee replacements. Is it possible to have phantom knee joints post-op? This question first came up after a recent case. A 70 year old patient of mine had been followed for run-of-the-mill osteoarthritis of the knee for some time. After a couple of years we had tried, with varying success, all of the usual medical treatments. When they finally failed, and rest pain started to become a problem we agreed that surgery was required. Ortho was consulted and a total knee replacement was performed rather uneventfully. Unfortunately, it was altogether too uneventful, in that the pain in the knee did not improve at all, not a bit, neither post-op nor four months later. At each visit the patient told me, rather accusingly, that the pain was exactly the same. On further questioning, the "exactly" she referred to was not just the intensity but also the quality of the pain. Constant but increased with weight bearing,primarily in the medial aspect of the knee. Now I know that post TKR pain is not that unusual, but I would think that hacking out the entire offending joint should at least modify the pain somewhat. Infection, incision, prosthesis, soft tissue or muscular pain could all contribute, but surely the pain would be at least somewhat different. One possiblity is that the original pain was not from the knee in the first place. I looked for soft tissue explanations and investigated the possibility that this was referred back or neuralgic but with no success. Granted it is difficult to completely rule out some referred source or peripheral neuralgia. In the end we did achieve partial relief with gabapentin but I'm still not sure what I am treating. The fact that the pain was identical made me wonder whether TKR can have phantom joint pain. It doesn't seem inpossible that a chronic persistant joint pain syndrome might have a central representation that persists after surgery. There is at least partial support in that some rheumatoid patients do continue to suffer from joint stiffness in their amputated limbs. This confirms that neuroplastic changes in the CNS can occur secondary to chronic arthropathy, and so it's not such a great stretch to suggest that the joint removal alone could be associated with a phantom joint. But how to prove it?