I'm not interested in doing inpatient rehabilitation, but I'd disagree with some of what has been said here. There are many patients that Ortho, IM, Neurology, and Neurosurgery want to get rid of and send to us, but that's not necessarily a bad thing for the patient. Often they want to "dump" them because they've done all they are able to and now that they are stable, they want to move on to the next patient. After the acute care, there are still lots of issues that haven't been addressed or dealt with properly. I think we manage TBI, SCI, Stroke, and Amputee patients much better than they would be managed on a medical or surgical floor. While we wouldn't be able to manage acute medical issues as well as an Internist, we are able to provide things that Internists can't that can be valuable for the patient's or caretaker's day-to-day life after discharge. Botox/phenol/joint injections, appropriate orthotics, presribing neurostimulants, dealing with neurogenic bowel/bladder, decubitus ulcers, etc.
With regards to PTs being better at the MSK exam, I'd say that this is probably true to some extent, but those of us doing procedures are still better at the clinically relevant part of the MSK exam. Other differences are that we are can order and interpret images, perform and interpret EDX studies as an extension of our physical exam, order and interpret lab studies, and rule out other non-MSK pathologies than PTs can't. We have both attendings and residents that were former PTs, but I don't think that any of them would say that this has made than a better clinician than those of us who weren't.
I've been fortunate in that our program allows ample time for us to spend with Physical Therapists in different settings (TBI, SCI, Amputee, Spine, etc.) and we have the opportunity to train with the top Orthopods, Neurologists, Neurosurgeons, Rheumatologists, and Radiologists at a variety of the Havard-affiliated hospitals. Having been on a variety of different services at different hospitals, I feel that our role in the inpatient setting is to stabilize the patient, coordinate care, recognize and treat specific sequelaes, maximize their function, and to make sure certain tests or diagnoses weren't missed. In the outpatient physical medicine role, I feel that we are really the experts in non-surgical orthopaedics. Our role at the hospitals we rotate through is to do the gait analyses, EDX studies, Botox/Phenol injections, spinal interventions, medically manage the patient's pain/spasticity, and presribe the proper orthotics. Based on what we are or aren't able to do will determine whether or not the patient can avoid surgery and how well they will function in their daily lives.
While some of the above can be done by an Anesthesiologist or Neurologist, neither of them can offer the comprehensive medical orthopaedic care that we can. This is also the reason why many of the Physiatrists that I know (either personally or from my program) have opted to complete a PM&R residency after practicing as an Anesthesiologist, Internist, Physical Therapist, or Neurologist.