Hi Keith,
I enjoyed your post, and I'm glad you're doing well. I've given some thought to the "foreign" feeling - it's my primary post-surgery symptom. No answers, just lots of layperson theories.
First, let me say that I'm delighted with my resurfaced hip functioning. But it still doesn't feel natural to me. Another factor is the athlete's perspective. I talked with a friend who is a serious cyclist who coincidentally underwent surgery the same weekend as I. His coach told him that Dr.'s, nurses, therapists, et al. might tell him he's doing fine. And for 90-some % of the population that doesn't push their body in athletic endeavors, you are doing fine. If you are interested in walking, hiking, maybe a little jogging, it's a complete success. But if you want to really get back to a pre-surgery state, be aware that from the athlete's perspective, you are at the far end of the bell curve. Recover is going to take a lot more work and a lot more time.
Inherent foreignness of the prosthetic.
* The complex of muscles that work with and in and around the hip, grew up with your body and with your natural hips to work with your previous hip joint. I don't know if they'll ever completely adapt, but I feel like there is still a bit of a mismatch between all the flexors and stabilizers, etc. and the fake hips.
* The prosthetic itself is certainly a marvel of medical technology, but I'm sure a properly structured, healthy, natural hip joint is far superior in many aspects. Just one aspect: the weight is different. Your balance will be off a bit. In a couple more decades maybe they'll be implanting natural bone replacements. Now the cobalt chromium is state of the art, but it's not the real thing.
* Aging and memory. Like you, my hips declined gradually. When I recall non-impaired hip functionality, I was probably 10-15 years younger. Even if my prosthetic hips were as good as my natural hips when I was in my early 30s, the rest of the body is that much older. Fake hips aren't going to make me feel like a 29-yr-old again.
* Prosthetic placement. I've read many opinions that computer aided placement isn't really the best placement tool. The best surgeons rely on experience. Placement is more an art than a science at this point. And when I consider the degrees of freedom or whatever in the hip - forward/backward, sideways - I can understand why the software for computer assisted placement would be difficult. Even if the software could be developed, I wonder if it would try to determine the best placement you ever had in your life with your natural hips, or optimal placement regardless of what your natural hips were like. You might have had somewhat defective hips from birth, so it's not a matter of determining what *was* your best hip placement, but what *would be* your best placement. And then you're in the realm of generalized formulas applied to you as an individual. E.g., optimal hip placement in the population at large might not be optimal for you given that your glutes are 32.5% bigger and your femur is 12.8% longer, and arms are 3.4% longer than population average. The body is such a complex thing that these calculations would be incredibly complex. Anyhow, what I was trying to say is that the prosthetic placement place and angle is probably pretty good, but it's probably not perfect. I don't think the medical state of the art is there yet.
Surgical symptoms.
* Most resurfacings involve pulling muscles out of the way and cutting some. The cut muscles are stitched together post surgery, but I'm sure you can imagine that it takes a long time and rehab work to recover. My Dr. mentioned that patients report significant improvements as much as 2 years post op, and speaking from my perspective 1 1/2 yrs out, I can attest to continued, noticeable improvements from the 12 month to 18 month period.
I hope this doesn't sound depressing. I get regular reminders of how great the new hips are. I'm a better cyclist than I was pre-surgery. I can plan backpacking trips to the bottom of the Grand Canyon, where I couldn't physically consider that pre-surgery. I can play pickup hoops and badminton and such with my kids. But when I went with a couple of my hockey buddies to watch them play a couple weeks ago, I told them that I'm not going to try to return to my former primary athletic endeavor - goaltending - until my hips feel more natural.
Life is good,
-Dirk