Advances in Hip and Knee Surgery: Q&A with Bernard Stulberg, MD

Dr. Bernard Stulberg is an orthopaedic surgeon specializing in hip and knee surgery and replacement. Dr. Stulberg graduated from University of Michigan Medical School and completed an orthopaedic residency and an orthopaedic research fellowship at Hospital for Special Surgery in New York City.

Knee Replacement

Q: If you are knock-kneed, should you replace both knees at the same time for better alignment?

A: Replacing both knees at the same time is more of a safety issue than a mechanical one. If both knees are contracted (stuck in a bent position), that would be a definite reason to consider double replacement. For some patients, however, doing both knees at the same time is not as safe as doing a single knee replacement procedure.

Q:*What is your opinion of ligament-sparing total knee replacement?*

A: Arthritis can result in damage to the knee ligaments. If they are spared, it is nice to try to use them. If not, it is better to use devices and designs that don't rely on them.

Q: Are there a variety of implant sizes to fit various knee sizes?

A: Yes there are. However, statistically, there may always be 5% of patients whose geometry is not exactly matched to the size of the implant. There are techniques to address this surgically, so designing a custom part for that patient "outlier" isn't really necessary. (We tried that in the past. It doesn’t seem to make a difference clinically.)

Q: If you replace your knees, are you setting yourself up for problems with your hips?

A: No. (That's the quick answer.) Hip arthritis and knee arthritis are often not related, but they can be found in the same patient. Statistically, knee arthritis is five times more common in women, whereas hip arthritis is about 50-50.

Q: What type of infection can affect a knee replacement? How do you prevent it?

A: Any bacteria (bug) can cause infection around an artificial device. It is to be avoided at all costs. That being said, it is impossible to avoid infection 100% and the more complicated the surgery, the higher the risk. In the best of hands, infection should be a 3/1000 incidence for primary joint replacement, with the national quality standard set at less than 1% (10/1000). Ask your surgeon what steps he or she takes to minimize infection.

Q: Are foreign body reactions still a problem with joint replacements?

A: Allergy to implants is very rare. All implants are, in theory, "foreign bodies." Implants are very well-tolerated because the materials are non-allergenic alloys. When implants begin to deteriorate due to wear, the body will react to them, but it is due more to the wear process than to an allergy.

Knee Replacement Options

Q: What is the difference between a full and partial replacement?

A: Partial replacement addresses only the part of the knee that is diseased, a common phenomenon of osteoarthritis of the knee. (Osteoarthritis is the most common form of arthritis.) There are strict "indications" for the use of partial arthroplasty, which requires and preserves all ligaments. If those aren't functional, or if the arthritis is more widespread, a complete replacement is a better choice. Roughly 15% to 20% of patients with knee arthritis are estimated to be candidates for partial knee arthroplasty.

Q: What are some noninvasive procedures for dealing with arthritic knees?

A: Exercises, medications, injections, arthroscopy, and sometimes partial replacements can be used.

Q: If the knee is bone-on-bone, can the noninvasive procedures be of benefit?

A: No, but if it has few side effects and is non-surgical, it may be worth a try. Percentage-wise, they may not be that successful.

Q: Is there a device currently being used or on the horizon either for partial or total knee replacement that allows for running (distance) post-surgery? It seems that after joint replacement the advice is “minimal activity.”

A: The advice is not minimal activity. In fact, in many ways, the more active you are the better. Impact activities are the ones we worry about the most (things like running and jogging), and much of that is based on laboratory and theoretical issues of wear on the bearing surfaces. With the newer technologies, this may not be as true. Having said that, many patients do, indeed, do whatever they want, and many are very active (doubles tennis, singles tennis, jogging, etc.). However, there are a few restrictions for patients with modern devices with current materials.

Hip Replacement

Q: I am an active 59-year-old female with osteoarthritis and deterioration of cartilage in the hip. Do you recommend hip replacement or resurfacing? Is there an optimum age for surgery, or is it always when you can't tolerate the pain any longer?

A: I recommend total hip replacement – no question. There is a lot of controversy about hip resurfacing, which is best reserved for the young, active male. Still, there are questions of longevity and metallurgy to worry about with resurfacing.

Q: What was the cause of the Johnson & Johnson hip recall? Was it just more of their quality problems in general?

A: The J&J recall was specifically for one product – the ASR – which is a metal-to-metal hip implant. There are still many unanswered questions about this specific implant and the metal-on-metal hip replacement in general. J&J has provided the orthopaedic world with many excellent products. Please don't confuse this product with their entire product line, which many surgeons have used for more than four decades – safely.


Q: What is the upper age limit for knee replacement?

A: That depends on physiologic status of the patient. Occasionally, a patient in their late 80s or 90s is an acceptable risk. We like to consider partial replacements in some of these patients, if it is possible.

Q: I'm 54 and was first advised to have a total hip replacement 10 years ago. Second and third opinions advised me to wait as long as possible, preferably until I'm 60. I've managed pain through various techniques, but it's increasingly difficult. Do you agree with waiting until 60 for a very active person? What is the estimated life for a hip replacement?

A: Theoretically, the longevity of a hip implant is better if you are less active, and patients who are over 60 are likely to be less active. Current designs, techniques, and materials may make this a less significant issue. Surgeons have a wide variety of opinions (biases), and I have mine. It is a quality of life issue for many patients, and I think current technologies provide me the tools to predictably get 20-year results for patients, with reasonable fall-backs if they get into trouble. That is the discussion I have with my patients. It's their choice after that.

Q: Why is 50 too young for knee replacement? I would think that being younger and healthier would make for better outcomes.

A: Good point. Statistically, the outcome should be better, but the data suggest that young males often do worse. The other side of the coin is that the under 50-year-old may very well do better and then will use that device more vigorously, risking it wearing out or otherwise getting into trouble. For selective patients under age 50, a total knee arthroplasty is a quality of life restoring operation. We don't deny those patients if they understand the issues.

Q: Can an 89-year-old get a HemiCAP for her knees?

A: Maybe, but it is experimental in my book. It is better to do a unicompartmental replacement.

Q: What is the upper age limit for “joint resurfacing?”

A: I reserve joint resurfacing for male patients under age 50, but the published numbers are women under age 55 and men under age 60. There are resurfacing enthusiasts who may push those numbers for some patients.


Q: Is there a knee replacement that uses ceramic and is good for 30 years?

A: I dislike the ad about the 30-year knee. Any device properly implanted, properly used, and properly designed has the potential to go 30 years.

Q: Will excessive exercise wear out artificial knees quicker (ceramic replacements)? I was told my knees will last approximately 10 years. I’m into my fifth and sixth year already.

A: Chances are pretty good you will get to 15 to 20 years if you use them properly. Many doctors told patients they last for only 10 years. That doesn't have to be the case at all.

Q: Why can’t they use metal instead of plastic in knee replacement?

A: They do, but a metal-to-metal articulation won't work. The knee does all sorts of motions that a hip doesn't do, and metal articulations can't successfully resist them.

Q: Do you know if any hip replacement suppliers are using Chinese titanium, which has been shown to be highly suspect in other applications?

A: I sure hope not. I have operated and taught in China, and they are behind us on the curve of design and implantation. Many US and European manufacturers are currently selling in China. However, if the devices pass the FDA regulations, they are probably OK.


Q: If you are 85 years old and in relatively good health, how well will you recover from a total hip replacement? What are the most common problems to be expected at this age?

A: Physiologic age is most important. If you are 85 but have well-managed medical conditions and are active, hip replacement can be a very safe and effective operation. In our experience, the most common problems for those over 80 are problems with the heart (usually in those patients who have pre-exiting heart conditions) and urinary tract problems. Many patients in their 80s are thrilled with their results and the experience.

Q: What are the average ‘recovery times’ from full knee replacement and partial knee replacement? What should a patient do to minimize recovery time?

A: This is a really good question. Recovery is a lot about how you, as a patient, prepare yourself for and work to have an excellent result. Preoperative strengthening (perhaps with physical therapy support) has been shown to result in faster postoperative recovery.

In general, I tell my patients it takes about three weeks to become ambulatory without a walking aid with a partial knee replacement, and up to six weeks for full knee replacement. These are only estimates, as some patients can be fully ambulatory within two weeks with either approach. Range of motion is usually easier to recover after partial versus full knee replacement. Partial arthroplasty recovery averages between six to eight weeks and complete knee replacement recovery is about three months, with some patients needing up to 6 to 12 months for recovery (a bit more variable).

Advances and Research

Q: Is any research being done on an injection that can get between the bones and provide cushioning so that surgery doesn't have to be done?

A: Yes, but I am probably not the best one to provide you with an update on it. Any of those solutions, to this point, are only temporary and may only be effective in the very earliest stages of the disease.

Q: What happens after 20 years in a wheelchair? Can there be a second operation? Is there any research in growing bone material as you grow skin?

A: Patients who have been in a wheelchair for more than 20 years are likely to have a very difficult time walking. I am not certain that replacement approaches have been very successful in restoring walking capabilities to this population of patients, although it can be helpful in addressing pain. There is plenty of research being done on growing bone materials, but again, this is not my area of expertise and I think success has generally been in the younger patient population (ie, younger than 20).