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Frequently Asked Questions: Total Knee Arthroplasty
Jeffrey M. Nakano, MD
www.rmodocs.com
970.242.3535
Rocky Mountain Orthopaedic Associates
Introduction
Total knee arthroplasty is a procedure that was developed in the 1960’s in order to
alleviate the severe pain associated with arthritis of the knee joint. Over the years the
technique has been improved, and now it is truly one of the success stories of modern
medicine.
General Questions
How will I know when it is time for me to replace my arthritic joint?
Total knee arthroplasty should be considered if x-rays demonstrate significant destruction
of the joint due to arthritis and if nonsurgical treatments have failed. Nonsurgical
treatments would include activity modification such as using a cane, weight loss (if you
are significantly overweight, and there are non surgical and surgical options that might
help you in this regard), use of arthritis medications/joint injections, and gentle exercise
to maintain muscle tone and joint motion. In general, surgery should be considered when
the enjoyment of life is seriously compromised by the pain one is experiencing.
What will I be able to do physically after my knee is replaced? Will I be able to
run? Will I be able to squat and kneel?
It is important to have realistic expectations of your total knee arthroplasty. A successful
knee replacement will enable a person to return to the routine activities of daily living
with a significant reduction in their level of pain (though not always complete). There are
certain restrictions, however. Jogging, jumping from heights greater than a one or two
feet, and other impact loading should be avoided. Tennis.skiing and racketball are not
advised, but golf, swimming, and road bicycling are reasonable pursuits. Most people
with artificial knees will not be able to squat or knee comfortably, but it is okay to try.
Can both of my arthritic knees be replaced at the same time?
The simple answer to this question is yes. However, nearly every study that has looked at
this question has shown that there is an increased risk associated with having both knees
replaced at the same time. I would certainly not recommend this unless both knees are
quite bothersome. In addition, I would not recommend that both knees be done at the
same time in any patient over the age of 75, or in any patient with significant heart or lung
problems.
What is the prosthesis made of?
The components are generally made of cobalt chrome with a polyethylene (plastic) spacer
that separates the two metal parts.
How large is my incision going to be?
The incision will typically be between 4 and 8 inches depending on the size of the knee
and the amount of surrounding tissue. I feel that the incision needs to be as large as
necessary to implant the artificial knee accurately.
Will my knee be straight after surgery (if you are bowlegged or knock kneed before
the surgery)?
Yes, one of the goals of surgery is to improve the alignment of the knee.
How much will I be able to bend and straighten the knee after surgery?
My goal is to try and achieve full straightening and enough bending to climb stairs and
get out of a chair without having to use your arms to push out of the chair. This is
typically about 105 degrees of bend, though many people achieve more than that
(someone who can squat and touch their heels to their buttocks has about 155 degrees of
bend). People who have significant limitation of knee bending prior to surgery usually
will have significant limitation of knee bending after surgery.
How long will my artificial joint last?
The failure rate is about 1% per year for the first 20 years for the average 65 year old
patient who receives a total knee. So, after 20 years the chances that the knee will be
functioning are in the 80% range. If you are younger and more active or heavier, the
failure rate is higher. Extensive data does not exist for longer follow up periods, but like
any mechanical device, the failure rate probably increases with time.
What are the main complications?
The two major complications that can cause failure of the knee are infection and
loosening of the prosthetic components. Infections will occur in 1-2% of cases, whether
the surgery is done at St. Mary’s Hospital or the Mayo Clinic. Great care is taken to try to
prevent bacterial contamination of the wound, but since these organisms are present in the
air around us, we cannot always be successful. If infection does occur, further surgery
and hospitalizations will probably be necessary. Often, the prosthesis will have to be
removed initially, and then replaced when the infection has been cleared by taking
appropriate intravenous antibiotics.
Loosening is the second major complication. A successful knee replacement depends
upon a good bond between the bone and the artificial knee components. If this bond
loosens, the knee will be painful and may have to be replaced. This bond is usually
achieved with a type of cement that holds the prosthesis to the bone. Risk factors such as
large body weight or excessive impact activity will lead to higher loosening rates.
In less than two percent of cases there will be problems with the kneecap dislocating or
other types of knee instability. If this occurs, further surgery to correct the problem may
be necessary.
Another complication is blood clots that can form in the blood vessels of the leg and
pelvis. While this problem can cause pain and swelling in the leg, it is the potential for
the blood clot to break off and go to the lungs and compromise breathing that makes this
complication potentially serious.
Other possible risks include nerve or blood vessel injury and disease transmission (AIDS,
Hepatitis) via blood transfusions.
What measures do you take to try to prevent infection?
Infections after artificial knee surgery are a risk of the surgery, just as an automobile
accident is a risk of driving. I use perioperative antibiotics, laminar flow operating rooms
(special operating rooms that have a high air turnover rate), and so-called “space suits”
that prevent bacterial shedding onto the surgical field from the surgery team. It has also
been shown that limiting the traffic in and out of the rooms is helpful, and we try to do
this as much as possible We require preoperative dental and physical examiniations to
determine if there are factors present that might increase your risk of infection. The
hospital provides special skin cleansing agents to be used just prior to surgery to further
decrease the risk of self contamination.
What measures do you take to try to prevent DVT (Blood Clots)?
Blood clots that go to the lungs and cause a pulmonary embolism can be a very serious
consequence of surgery. You will typically be on two or three forms of anticoagulation
during your hospitalization: 1) mechanical foot pumps, 2) Lovenox (enoxaparen) shots
in the skin over your stomach, 3) Coumadin (warfarin) pills. In addition, pointing your
toes and foot upward and downward and contracting your calf muscles at every
opportunity will be helpful in preventing clots. When you leave the hospital you will
continue on either the Coumadin pills or the Lovenox shots. There is no data to definitely
support one form of treatment over the other at this time. If you take the shots you will be
on the medication for 1-3 weeks after surgery. If you take the pills, you will be on the
medication for one month after surgery. After you finish the pills or shots, you should
take one aspirin (81 or 325 mg) per day if you can tolerate it. If your insurance does not
pay for prescription drugs, I would recommend Coumadin pills over Lovenox shots, since
there will be a lot less out of pocket expense. If you are on Coumadin, you will have to
visit the coagulation management (Coumadin) clinic (entrance 22 at the Pavilion) every
several days to monitor your level of anticoagulation. This is not necessary, if you are on
the Lovenox shots.
Before the Surgery
What do I need to do to get ready for the surgery?
1. If you haven’t seen your primary care physician for a while, you will probably
need to see him/her. Your internist or family practice doctor will check your heart
and lungs to make sure you are in good shape for the surgery. This visit should
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take place at least a couple of weeks (and preferably several months) before your
operation so that steps can be taken to evaluate and correct any abnormalities.
If you haven’t seen your dentist in the past few months, or if you contemplate a
visit to your dentist in the 4 months following your surgery, you should see
him/her prior to the surgery. This is necessary to make sure there are no occult
pockets of infection around your teeth that may spread bacteria through the
bloodstream to your new joint.
Some patients will wish to donate their own blood to the blood bank so that they
can get their own blood back after surgery, if they require a transfusion. The risk
of getting a disease such as AIDs, hepatitis, and CMV is less than 1:1,000,000.
The risk of major transfusion reactions is similar whether you donate your own
blood or not. The odds of having a transfusion for a total knee are less than 10%.
In addition, your donated blood will be discarded if it is not used. For all these
reasons, I no longer recommend giving your own blood before surgery.
You will have some lab work done prior to surgery. A urine test and an EKG (to
measure heart function) will generally be done as soon as you schedule your
surgery. A blood count, chemistry profile, and other blood tests will be done
about 28 days prior to your surgery. Any abnormalities on these tests may require
further evaluation. Often, we will obtain screening lab work 6 or more weeks prior
to your surgery. If there are abnormalities, we will have plenty of time to correct
them prior to your surgery. Unfortunately, some of the lab work will have to be
repeated in the month prior to your surgery, since it will be outdated.
Pre-operative physical therapy can be helpful, particularly if you are
deconditioned due to your arthritic joint.
If possible, stop taking aspirin and arthritis pills like Motrin, Naprosyn, Aleve,
Advil, Ibuprofen, etc. one week before surgery. This may decrease your
intraoperative and postoperative blood loss. Some anticoagulants like Coumadin,
Plavix, Aggrenox, and Persantine, and some herbal medications should be
stopped prior to surgery also. Some medications that are taken for rheumatoid
arthritis like methotrexate and Remicade must be stopped prior to surgery.
Continue to take blood pressure and heart medications until the morning of
surgery (with just a sip of water on the morning of surgery). If you are taking
aspirin for known coronary artery disease, you should continue to take the
aspirin right up to the day of surgery. Tylenol (acetaminophen) and narcotic
pain medications are permitted until the time of surgery.
Avoid scratches or cuts on your legs in the days prior to your surgery (stay away
from your cat, rosebushes – or at least, wear long pants, don’t shave your legs).
Bacteria will colonize these wounds and this will increase your chances of
postoperative infection. Be sure that you call me before your surgery if you
should notice a cut, ingrown hair, pimple, etc. in the area around your surgical site
or infection in any part of your body. Use the antibacterial cleansing agents
provided by the hospital prior to your surgery.
If you should develop a cold in the week prior to your surgery, be sure to call the
office. If you have a temperature, productive cough, or pneumonia, your surgery
may have to be rescheduled.
9. If you feel that you will not be able to safely return to your home after your
surgery and hospitalization, then there is usually the option of going to one of the
skilled nursing facilities around town (located in part of a nursing home). If you
think that this is a possibility, you could consider visiting these facilities prior to
your surgery to see if you have a preference.
Hospitalization/Surgery
Do you operate at St. Mary’s Hospital and Community Hospital?
Yes, I operate at both hospitals, but the great majority of my surgeries are done at St.
Mary’s hospital where I have specific surgery days every week that are reserved for my
patients. In addition, St. Mary’s has a special orthopedic wing staffed with nurses who
take care of only orthopedic patients.
Will I have a private room?
All of the rooms at St. Mary’s Hospital for patients with artificial joints are private rooms
with a bathroom. The rooms at Community Hospital are semiprivate (two people to a
room), but they will try to keep only one person in the room if possible.
How long will I be in the hospital?
The typical length of stay after an artificial joint is 2 to 4 days. If your operation occurs
on a Thursday, your third day after surgery would be Sunday. If it seems you will not be
able to return home by five days, the discharge planner at the hospital will help you locate
a skilled nursing unit at one of the facilities in town where you will receive physical
therapy. You will be able to stay at that facility until you are ready to go home. If you are
able to get out of bed and walk down the hall on the first day after surgery, this generally
means you will be able to go home by the third day after surgery. While the services that a
hospital provides are a necessary part of your recovery, staying in the hospital
environment will increase the risks of picking up an infection with resistant bacteria. I
think that it is in your best interest to leave the hospital as soon as you are able
Should I have a friend or family member stay with me at night during the
hospitalization?
In general, I do not think that this is necessary. You will find that the nurses and
assistants on the orthopedic unit at the hospital are quite attentive. The rooms for patients
with artificial joints at St. Mary’s are private so there is certainly enough space for
another person to sleep in the room, if you feel that you may have special needs.
Can I select my anesthesiologist? Do you, as the surgeon, have a preference?
Yes, you can request a particular anesthesiologist, and we will do our best to honor your
request, as long as that particular physician is available on the day of your surgery. I
personally do not have a preference, I think all of the anesthesiologists that I have worked
with are extremely competent.
Should I have a general anesthetic or a spinal anesthetic?
The anesthesiologist and you will make that decision. I would favor a spinal anesthetic
for myself. A spinal anesthetic involves the injection of a local anesthetic (a numbing
agent similar to novacaine) into the area of the lower back around the nerves that go to
the legs. This produces a temporary loss of pain sensation in the hips and legs allowing
surgery to be done. If you are concerned about feeling or hearing during the surgery, a
sedative can be administered that will induce a light sleeping state. Duramorph is a form
of morphine that prolongs the effects of the spinal for as much as 48 hours after surgery.
If you are allergic to morphine, you should not have Duramorph. A general anesthetic
occurs when you are given medication that puts you into a deep sleep and a mechanical
device is used to breath for you. It can be combined with a femoral nerve block to
decrease the pain after you wake up. A femoral nerve block is produced by injecting a
local anesthetic into the femoral nerve in the proximal thigh. An advantages of a spinal
anesthetic over a general anesthetic is that it decreases the chances of blood clot,
Sometimes, there are problems with nausea and itching following anesthesia. These can
usually be controlled with medications, but you need to alert your nurse if you are having
these symptoms so the medications can be administered.
How will my pain be controlled after surgery?
You will have a choice of postoperative pain medications to choose from. A narcotic
pain pill such as hydrocodone or oxycodone combined with Tylenol will be ordered, and I
would suggest that you ask for the pain pills starting the day of surgery if you are having
enough pain to require medication and are not nauseated. If the pain pills are not
sufficient to control your pain, you will be given a PCA (patient controlled analgesic)
device. This is a button that you can push that is attached to a machine that will
administer a of narcotic pain medication through the IV in your arm. The machine will
deliver a set amount of narcotic pain medication based upon your age, weight, and health.
Overdosage is not likely, so don’t be too concerned about how often you push the button.
The PCA device is usually discontinued by the second day after surgery, but your input is
important. If your pain is still not controlled, notify your nurse and additional measures
can be taken to make you as comfortable as possible.
How will I go to the bathroom during my hospital stay? Will I need a bladder
catheter?
Male patients have an easier time with this. They can use a urinal in bed during the first
24-48 hours, after that they can generally go to the bathroom that is in each room. On the
other hand, males have a greater chance of requiring a Foley catheter (a flexible tube
inserted through the urethra, into the bladder), which is inserted if urinating is not
possible. Sometimes, after anesthesia, males are not able to initiate a stream,
particularly if there are pre-existing prostate problems. Females can use a bedpan in the
first 24 hours, but sometimes they require catheters also. Catheters are generally removed
within 48 hours, since longer use of catheters may result in a bladder infection. It is rare
to have a bowel movement in the first 24 hours after surgery. Constipation can be a
problem due to narcotic pain medications. I routinely give stool softeners in an effort to
prevent this problem. Various laxatives, suppositories and enemas are available if you
need further assistance. If you routinely take a particular medication for constipation,
bring it with you to the hospital and notify your nurse when you get to the orthopedic
floor.
Can I sleep on my stomach or my side?
You can sleep in whichever position you are comfortable. If you sleep on your side it
may be more comfortable to have a pillow between your legs. During your
hospitalization you may be placed in a CPM (continuous passive range of motion)
machine which will move your knee while you are resting in bed. Since no study has
every shown any long term benefit with this machine, we do not require that you use it if
you are more comfortable without it. If you choose to use the machine, you will have to
sleep on your back.
Why do the lab technicians come in and draw my blood every morning?
One tube of blood is obtained in order to determine how low your blood level is (how
anemic you are). It takes three days for your blood level to equilibrate after blood loss at
surgery, so we usually check it for the first three days after your surgery. Another tube of
blood is sometimes drawn in order to check your level of anticoagulation (how “thin”
your blood is on Coumadin which may be administered in an effort to decrease your
chances of getting a blood clot).
When will I be able to get in the shower?
You will be able to shower and get the incision wet when the drainage from the incision
is minimal. Usually, this will occur on the second day after surgery. However, you
should avoid soaking your incision in a bath or hot tub for three weeks after surgery
unless instructed otherwise.
When will you see me when I am in the hospital?
I will see you on the evening of your surgery (between 5:00 and 8:00 PM), the morning
after your surgery (between 6:30 and 8:00 AM), the second evening after your surgery
(typically between 6:00 and 10:00 PM (unless this falls on Saturday), and then every
morning until you leave the hospital (between 6:30 and 8:00 AM). On the weekends I am
typically on the orthopedics floor for three hours from 8 – 11am. One of my partners and
a physician’s assistant are available 24 hours per day. I will call and speak with your
nurse at approximately 11pm on the evening of your surgery to make sure you are not
having any problems.
Physical Therapy
What will the therapists expect of me during my hospitalization?
Two types of therapists will be working with you. A physical therapist will teach you
how to get about safely with your walker or crutches. Even more important, the physical
therapist will instruct you on the proper technique for maximizing your post operative
range of motion. Careful adherence to these instructions will give you the best result
following this operation. An occupational therapist will help you with activities that you
do on a daily basis, such as dressing, showering, etc. Sometimes, patients will feel dizzy
when they get up the first day after surgery. This is usually a temporary problem. Make
sure you let your nurse or therapist know if you feel dizzy when you first get up, they will
let you sit down, so you don’t faint.
Will I need out patient physical therapy after I am discharged from the hospital?
Physical Therapy is generally required after discharge from the hospital, though not
always. I generally send patients to the St. Mary’s Life Center located near the
intersection of 12th Street and Patterson Road. If you know another physical therapist, we
will be happy to send you to that therapist instead. Physical therapy can be obtained
through home health, and they will come to your home. Some of these therapists are
quite experienced; others are not. For this reason I have a preference for outpatient
physical therapy.
May I participate in water aerobics if I wish?
Yes, but I would recommend that you wait until three weeks after your surgery unless
otherwise instructed.
Do I have to use a walker to get about? How long?
I would recommend that you use a walker or crutches at first. It is important to avoid
falling and hurting yourself or your new knee. If you are allowed to bear full weight from
the beginning you can progress to a cane or no external support as long as you do not
limp. If you are limping you should go back to the device that allows you to walk without
limping. Most people feel that using the cane on the side opposite from the surgery is
most comfortable.
I have stairs in my home. Will I be able to go up and down stairs after I leave the
hospital?
The physical therapists will help you master the skills necessary to navigate stairs while
you are in the hospital. You will have to modify how you accomplish this at first, but
gradually you will probably be able to go up and down stairs normally.
After You Are Discharged Home
What time will I be discharged from the hospital?
You can usually plan to leave around noon on the day of discharge, after you finish your
morning physical therapy. You can eat lunch at the hospital if you wish.
What are the reasons I should call the physician prior to my first appointment?
1. If your pain is not under control.
2. If drainage from the incision persists more than 7 days after your surgery. Or,
if you notice increasing redness and swelling around the incision.
3. If you develop calf pain, shortness of breath, or chest pain (all signs of a
possible blood clot).
4. Signs of infection such as increasing redness and swelling around the incision,
temperature greater than 101.5 degrees.
5. Any other concerns
When are my post op appointments scheduled?
Bill Etenburn, the PA that has worked with me since 1988 will typically see you at 2 wks
post op to inspect the incision and to get x-rays of your new joint. We will then see you
at about 4 weeks, 8 weeks, 12 weeks, 6 months, and 13 months post op. We will
continue to see you at 2 year intervals after the first year in order to obtain follow up xrays. The x-rays are necessary to make sure that there are no signs of impending
problems. Remember, your artificial joint is a mechanical device, and all mechanical
devices will eventually fail. Sometimes, a relatively simple procedure can be done, if we
know that something is going wrong early on.
Will Home Health be necessary?
This is usually not necessary if you go home, but can be arranged through the hospital’s
discharge planner prior to the time you leave the hospital.
When can I start having sex again?
Sex can be initiated as soon as you are comfortable, probably 4 to 8 weeks after surgery.
When will I be able to drive?
You should be off of your narcotic pain medications during the daytime, if you are going
to drive. You should also have good control of your leg, which means you are usually
getting around on a cane (as opposed to a walker). As long as these conditions are met,
driving at about 4 weeks postop is reasonable.
Can I get refills of my narcotic pain medications after I get home? Why don’t you
put automatic refills on my original prescription?
Refills should be requested from our office between the hours of 9am and 3pm during
weekdays. Because of widespread illegal narcotic use, refills requested after those hours
or on weekends will not be filled until the next business day for my office. I do not
authorize automatic refills because I wish to know how rapidly you are using the pain
medication. Uncontrolled pain can be a sign of problems such as infection.
Will I have to use the machine that bends and straightens my artificial knee (CPM
machine)?
No study involving these machines has ever shown that it improves the long term result
of an artificial knee. As a result, use of the machine during and after your hospitalization
is not manadatory. We generally do not send the machine home with you.
Is bruising normal?
The amount of bruising around the incision is variable. Sometimes it will extend down
the leg to the foot and up your thigh. Often times the medication you are getting to try to
prevent blood clots will contribute to more bruising.
My knee clicks (pops, grinds). Is that something to worry about?
As long as the clicking (popping, grinding) is not particularly painful or associated with
instability, there probably is not much to worry about. The metal and plastic components
of the artificial knee usually make some “noise”. Sometimes scar tissue inside the knee
will cause a grinding sensation. If the plastic component wears through after a long
period of time, the metal on metal grinding that can occur will feel like a fine vibration
and is usually associated with swelling. If you experience that type of sensation, you
should call immediately.
Is it normal for my knee to feel stiff after surgery?
When you first get up in the morning and after you sit for a while, you will find that your
knee is stiff when you first stand. This will slowly improve over the first year, but some
people always have this problem to some degree. Increased skin temperature of the knee
and swelling may persist for a year after surgery.
Is it normal for the skin in front of my knee to be numb?
The skin will be numb on the lateral side of the incision because the nerves going to that
area are cut when the incision is made. You will always have some degree of numbness,
but it will improve over time to the point that it will not be noticeable by most patients.
How long will it take for me to recover from my surgery?
1. Recovery from the surgery (the point that you feel that you are doing reasonably
well) is about 3 months, but you will continue to improve for 1 year after surgery.
2. The bending and straightening will usually improve for one year after the surgery, but
generally, by three months you will have achieved about 80-90% of your final range
of motion.
3. Fatigue is typical for 3 months after surgery.
4. A poor appetite may persist for a month or two after this surgery.
5. Some people may find that they are temporarily depressed after this operation, even if
they were not depressed before the surgery. Sometimes antidepressant medication
will be helpful for this problem.
I hope that this information is helpful. Please feel free to call if you have any further
questions.
Jeffrey M. Nakano, MD
970-242-3535