Online Health Chat with Dr. Viktor Krebs and Dr. Robert Molloy
June 7, 2010
Cleveland_Clinic_Host: When knee pain interferes with everyday function, surgery may be recommended. Based on the amount of arthritis or wear on your joint, innovative alternatives may be recommended: Partial knee replacement, patellofemoral resurfacing and advanced knee replacements (which function more like a natural knee). Partial replacement and patellofemoral resurfacing are indicated when damage is limited to cartilage in one or two compartments of the knee. If knee replacement is the best option, new custom-tailored surgical tools and computer planning options may produce better comfort, function and realignment.
Viktor Krebs, MD, is the Director for the Center for Adult Reconstruction and General Orthopaedics. His specialty interests include hip and knee replacement, hip and knee revision surgery and hip arthroscopy. Dr. Krebs earned his medical degree from The Ohio State University of Medicine and Public Health. He then completed his fellowship in adult reconstructive surgery at New England Baptist Hospital in Boston, Massachusetts.
Robert Molloy, MD, is a staff physician and Education Director in the Center for Adult Reconstruction and General Orthopaedics. His specialty interests include hip and knee replacement, including complex and primary revision hip and knee surgery, and hip and knee arthroscopy. Dr. Molloy earned his medical degree from Wayne State University School of Medicine in Detroit, Michigan. He then completed his fellowship in adult reconstructive surgery at New England Baptist Hospital in Boston, Massachusetts.
To make an appointment with Dr. Krebs, Dr. Molloy or any of the other specialists in our Department of Orthopaedic Surgery at Cleveland Clinic, please call 866.275.7496. You can also visit us online at www.clevelandclinic.org/ortho.
Welcome to our Online Health Chat with Dr. Viktor Krebs and Dr. Robert Molloy. We are thrilled to have them here today for this chat. Let’s begin with the questions.
Understanding Knee Replacement Surgery
berts: How long does Total Knee replacement last before it has to be done again? Is it better to put off surgery as long as possible?
Dr__Robert_Molloy: We expect modern knee replacements to last for at least 15 years, prior to needing revision. The new plastic we are using today in total knee replacements may allow this to last for 20-25 years, but it is too early to tell right now.
It depends on your quality of life. When it has been significantly impacted by your quality of pain from arthritis, then it is time to at least consider surgery.
Snowball: Have there been any specific advances in method or technology to reduce the pain experienced by the patient?
Dr__Viktor_Krebs_-_Dr__Robert_Malloy: Absolutely. We are continually doing studies in pain management in the perioperative (before, during and after surgery) time frame. We routinely use nerve blocks, local anesthetic injections, and have also been able to eliminate the intravenous medications that cause bad side effects, such as nausea and vomiting.
Getting a joint replacement today is significantly easier than it was 5 years ago, and it has a better long term result, motion and long term outcomes.
LynnK3: If you have a total knee replacement and all of the arthritis and spurs are removed, can arthritis re-occur in knee? Does arthritis come back?
Dr__Viktor_Krebs_-_Dr__Robert_Malloy: Arthritis is the process by which the joint wears out. It includes all of the things you mentioned. Once the worn joint surface is removed, the arthritis does not recur. With knee replacement, the actual joint is removed. Without a joint, there can be no osteoarthritis.
MissE: Are cortisone shots helpful to avoid surgery?
Dr__Viktor_Krebs_-_Dr__Robert_Malloy: Cortisone shots are useful to treat symptoms and lessen pain prior to surgery. They will not prevent the knee from deteriorating and ultimately will not prevent the necessity for a knee replacement.
Snowball: If someone has stress fractures in their tibia due to deterioration of the knee, how vital is it that the patient have a knee replacement, and is there a possibility that the bone could break when the procedure is being done? If so, what would be done?
Dr__Viktor_Krebs_-_Dr__Robert_Malloy: If there are stress fractures, they need to be carefully evaluated. Bone density tests should be done. We often allow them to heal before surgery, depending on their location.
If the worn out knee is causing the stress fractures, we recommend knee replacement.
It would be unusual to have an intraoperative fracture, but we do have stems and other ways to reinforce the bone.
JRD: I was told it takes as long as a year to fully recover from knee replacement. What takes so long?
Dr__Viktor_Krebs_-_Dr__Robert_Malloy: When a knee wears out, it occurs over a long period of time. During this time frame, not only does the joint degenerate, but the muscles and tissues also de-condition. When this is added to the extensive procedure required to perform a knee replacement, the body requires time to heal completely, recondition and get used to the new joint. This process truly takes a year, but most people see the benefits of the knee replacement in 6-8 weeks.
Knee Replacement: Total or Partial?
Snowball: What would be the criteria for doing a partial knee replacement versus a TKR (total knee replacement) specifically, how often is it done for the medial compartment only?
Dr__Viktor_Krebs_-_Dr__Robert_Malloy: The ideal candidate for a partial knee replacement is someone who has isolated medial compartment osteoarthritis with pain localized to the medial knee.
If the osteoarthritis or the pain is more diffuse, than total knee replacement may be a better option with a better long term result.
Partial knee replacement has become more popular over the last few years and has been described as a bridge procedure to a total knee replacement. We recommend seeing a surgeon who is comfortable doing both, so that the right procedure is done for you.
Knee Replacement: Is it Gender Specific?
wmt: Gender specific knees are they different from other knees? Should I only ask for a gender specific knee?
Dr__Viktor_Krebs_-_Dr__Robert_Malloy: There is definitely a difference between the male and female knee. All of the major orthopaedic manufacturers have addressed this issue.
In the past, knee replacements came in 4-5 sizes. Orthopaedic surgeons realized that these did not fit all of the patients appropriately. All contemporary knee replacement systems have increased the number of sizes up to 8 or 9, to more specifically fit the different anatomical variances.
At this point, I do not think that you need to ask specifically for a gender specific knee, as they are only sold by one company. I think it is more important that you choose a surgeon you are comfortable with and that has experience doing knee replacements.
Snowball: How many different brands of knee implants do you use at the Cleveland Clinic and what are the criteria for choosing a certain one?
Dr__Viktor_Krebs_-_Dr__Robert_Malloy: We currently use knee systems from all the major orthopaedic implant manufacturers. The choice is made based on the patient's anatomy and physician's preference.
Knee Replacement: Criteria for Surgery
Snowball: What are the weight guidelines for knee replacement surgery and can obese patients have minimally invasive knee surgery?
Dr__Viktor_Krebs_-_Dr__Robert_Malloy: The results are better when a patient's BMI is below 40. Actual weight numbers are not set criteria. In most situations, overweight patients are counseled by our dietary group and start to lose weight before surgery.
As to minimally invasive surgery, the length of the incision is proportional to the size of the thigh and calf. If they are large, a small incision is not safe, as the knee cannot be visualized or reconstructed appropriately.
dorcie: I had femoral artery bypass surgery 2 years ago. Am I a candidate for replacement and what are the risks?
Dr__Viktor_Krebs_-_Dr__Robert_Malloy: We have both operated on many patients with vascular insufficiency and following vascular bypass. The situation is much more complicated. It requires a multidisciplinary team, including orthopaedic surgery, vascular surgery and vascular medicine. This group evaluates the patient and then comes up with recommendations for the safest way to perform the replacement.
In most knee replacements, the tourniquet is used to limit bleeding. After vascular bypass, this may not be possible and different techniques are employed to do the surgery and conserve blood.
Because there are potential vascular complications, we always have a vascular surgeon available to assist, if and when they are needed.
jameseugene: When bone on bone in knee is seen on X-ray is the only option knee replacement? Is an MRI indicated?
Dr__Viktor_Krebs_-_Dr__Robert_Malloy: Once bone on bone is visualized on a plain X-ray, an MRI will not add value or change the diagnosed.
Often times, once you are bone on bone, if this cannot be medically managed or braced, knee replacement is the best option. Always remember that knee replacement is elective, and it is your choice whether to proceed or not. If your life is affected to the point that you are incapable of comfortably performing activities of daily living, knee replacement is an outstanding option.
Bilateral Knee Replacement Surgery
ms10: Is there advantage to having both knees replaced at the same time if they are both needed?
Dr__Robert_Molloy: The only advantage to having them both replaced at the same time, would be a potentially shortened recovery period. However, we know that having both knees done at the same time carries with it an increased risk of medical complications. These would include increased blood loss, post-surgical heart attacks, blood clots, pneumonia, bedsores, etc. Therefore, we are very selective on who we perform bilateral knee replacements.
For me to consider bilateral knee replacement, a patient would need to be relatively young, not obese, no history of MI (myocardial infarction or heart attack), no prior stroke history and not have diabetes.
xtra: I had bilateral knee replacements 16 years ago at age 52. I need both done again; what is the hospital time involved and what is estimated recovery time? My local surgeon recommends Cleveland Clinic second time.
Dr__Viktor_Krebs_-_Dr__Robert_Malloy: A hospital stay would be about 3-4 days, but this would depend on how extensive the surgery is - a plastic/bearing exchange versus a complete redo of the implants. If it is a complete redo, they likely would not both occur at the same.
As to recovery, if it is just a plastic exchange, then you would likely be on your feet the next day, walking with crutches and progressing to a cane within two weeks. If the implants need to be redone, it will be a longer process and will depend completely on how extensive the surgery was. Worst case scenario – 6-8 weeks per knee, with crutches.
Knee Replacement and Exercise
Snowball: Do you prescribe pre-op knee strengthening exercises?
Dr__Viktor_Krebs_-_Dr__Robert_Malloy: Yes. Studies have shown that this is very beneficial, if a patient is capable of participating. This allows for a more rapid recovery.
JP39: What about exercise after surgery recovery? Are there any exercises to avoid?
This would be patient specific. Overdoing it immediately after surgery may actually hinder your recovery. Following the plan set out by your surgical team is advisable.
Long term restrictions are minimal. We advise avoiding high impact activities, such as running, jumping, etc. Other than that, patients can have a very active lifestyle and are encouraged to do so.
sek3: How long before you should be able to fully straighten your knee after surgery?
Dr__Viktor_Krebs_-_Dr__Robert_Malloy: Three to four weeks. This will depend on what your motion was prior to surgery. Patients with significant loss of extension (ability to straighten) prior to surgery may lengthen the time to achieve a straightening.
myomy: Is it true that you can never kneel again after knee surgery?
Dr__Viktor_Krebs_-_Dr__Robert_Malloy: No. There is no data to suggest that kneeling is detrimental if patients have good range of motion after surgery. We would encourage good padding and frequent breaks. It takes 6 months after surgery for knees to be recovered enough to be comfortable kneeling.
dorcie: What are my limitations after knee replacement, like walking and kneeling bike riding??
Dr__Viktor_Krebs_-_Dr__Robert_Malloy: The only significant restriction I put on patients are repetitive, high impact activities, like running and jumping. I allow patients to walk and bike ride and do low impact activities as much as they want. Jogging is not recommended, but you can run to get out of the way of danger.
Most patients can return to activities they were proficient at before the procedure. Examples include, snow skiing, horseback riding, doubles tennis, etc.
Knee Replacement Complications
Snowball: What about infections? What is the rate of infection, and how can MRSA be avoided?
Dr__Viktor_Krebs_-_Dr__Robert_Malloy: The rate of infection, nationally, is less than 1%. Our infection rates at Cleveland Clinic are slightly lower.
We use perioperative screening and antibiotics, if patients are carriers of MRSA (antibiotic resistant staph infection).
Here at Cleveland Clinic, our infection control group has an elaborate process in place to minimize MRSA and its spread.
AGS: What damage may be caused to nervous system of lower legs/feet during knee replacement surgery? Does physical therapy help posterior tibial tendonitis?
Dr__Viktor_Krebs_-_Dr__Robert_Malloy: The risk of nerve damage in most patients is very low. For certain pre-existing knee deformities (ie. patients who are significantly knock-kneed) this risk may be higher.
Posterior tibial tendinitis is related to collapse of the mid-foot and can be evaluated by a foot and ankle surgeon or a podiatrist. Physical therapy and orthotics may help, depending on the stage of the disease.
Knee Replacement and Blood Transfusions
Snowball: What percentages of patients require blood transfusions during TKR (total knee replacement) and is it possible to bank one's own blood?
Dr__Viktor_Krebs_-_Dr__Robert_Malloy: The percentage of patients requiring blood transfusion really depends on the individual patient and their susceptibility to bleeding.
In general, less than 20% of people undergoing a primary unilateral total knee replacement require a blood transfusion.
In the past, we used autologous blood donations. Studies have shown that this process actually makes patients more likely to require banked blood products after surgery. This may be due to the fact that patient's who have donated blood are anemic at the time of surgery. At this point, we have essentially abandoned autologous blood donation at Cleveland Clinic, except for very special circumstances.
Knee Replacement and Spinal Stenosis
lex3: If you have Spinal Stenosis can you have knee surgery?
Dr__Viktor_Krebs_-_Dr__Robert_Malloy: We recommend that the spine be managed first.
If the spine team feels that the stenosis does not require surgery and can be managed medically, then spinal stenosis does not preclude knee replacement surgery.
Knee Revision Surgery
sally: How often does one need a second replacement done? Is it just as effective when you have more than one?
Dr__Viktor_Krebs_-_Dr__Robert_Malloy: With the technology being used today and appropriate activity levels, most knee replacements will last 20-25 years.
The effectiveness of the second or the revision surgery depends on the extent of damage and dysfunction of the failed knee replacement. If a knee replacement has completely failed and loosened from the bone, the results will likely not be as good as the first surgery.
The take home message is - if your knee replacement hurts, have someone look at it sooner, rather than later.
Cleveland_Clinic_Host: I'm sorry to say that our time with Dr. Viktor Krebs and Dr. Robert Molloy is now over. Thank you again Drs. Krebs and Molloy for taking the time to answer our questions today about knee replacement surgery.
Snowball: Thanks so much to the Doctor's for taking time to answer our questions!
Dr__Viktor_Krebs: We appreciate your enthusiasm and interest in knee replacement surgery. Hopefully we answered your questions and that you found this beneficial. Have a wonderful day. for more information, or to make an appointment, you can contact us at 866.275.7496 or online at www.clevelandclinic.org/ortho.
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