The Knee PDF Print E-mail
Friday, 23 October 2009 01:08

The knee is an important part of your lower extremity. It provides adequate motion to permit you to sit and stand. It is a magnificent shock absorber, absorbing as much as three to four times your body weight whenever you walk or jog. All of these are due to the cartilage that lines the ends of the bones.

knee anatomy

The knee joint is made up of the articulations between the end of the thigh bone (femur), the end of the leg bone (tibia), and the undersurface of the kneecap (patella). These surfaces are covered with cartilage, a very smooth and hard structure that provides good shock absorption and an almost frictionless bearing surface. When a person develops arthritis, cartilage is damaged. As the damage progresses, shock absorption capacity lessens and the almost frictionless surface starts to become rough. When these happen, the knee starts to swell, stiffen, deform, and hurt. The more damage that the knee sustains, the worse the symptoms will be.


Do I Need A Knee Replacement ?

Conditions that damage the cartilage of the knee can result in pain and stiffness. Over time, movement of the knee can become very painful. If the pain limits your participation in activities that you enjoy doing despite adequate nonsurgical treatment, then knee replacement surgery may be for you. It would be worthwhile to share your concerns, fears, and plans with your surgeon prior to deciding on whether to have the procedure or not. You may even be surprised to find out that some of your concerns and fears may not be real after all.

What Can I Expect After Surgery ?

Depending on which study one reads, knee replacement surgery can dramatically decrease pain and significantly improve function in 90 – 99% of patients. As a rule, you should be able to go back to the kind of life that you had prior to having knee arthritis. You will not need to take medicines similar to what transplant patients take since your new knee will be made of artificial components. There is virtually no rejection of the implants whatsoever. However, y o u will always have to be careful to avoid infections since the artificial components have no inherent protection against these. Furthermore, with normal use, some wear and tear will develop between the moving parts. In order to lessen the rate or wear, certain activities (such as high impact repetitive activities), will have to be avoided.

What Are The Risks of the Procedure?

Although most patients experience no complications, the surgery is a major orthopedic procedure and some patients may develop problems after the surgery. The more common risks are: deep venous thrombosis (developing blood clots in the veins of the legs), infection, excessive bleeding, stiffness, injury to blood vessels, nerves, or bone, early loosening of a component, and aggravation of an existing medical problem.

By carefully following the instructions of your doctor, you will be able to lessen the risks of surgery. Furthermore, your physicians at AOJR have trained long and hard in various centers abroad in order to minimize the chances of these potential complications occurring.


After you have decided to have the knee replacement done, we will have to make sure that you do not have any condition that may interfere with your healing after the surgery. This could take a week or two to complete.

Laboratory examination:

We would request for certain blood exams to make sure that you do not have problems such as anemia or an infection. A urine exam would also be requested. Any existing infection should be treated prior to the surgery.

Medical evaluation:

We would give you a referral to a cardiologist or an internist. He would normally request for other tests, such as an electrocardiogram (ECG) and a chest x-ray. He will make sure that you are fit to undergo the surgery. If you have other underlying illnesses, such as diabetes, prostate problems, or rheumatoid arthritis, we would likewise refer you to the appropriate specialist if necessary. Ideally, the physicians who give your clearances should come from the same hospital where you plan to have the surgery. This would decrease the chances of problems arising should their help be required during your hospital stay.

Dental evaluation:

One often overlooked source of possible infection after a knee replacement is the teeth. In order to lessen the chances of infection from this source, we will request you to have your teeth and mouth examined by your dentist. If everything is fine, he should give us a written clearance to that effect. Otherwise, if there are dental problems that have to be treated, these should be addressed first prior to having your surgery.


It is important to inform your doctor what medications you take. Some medications, such as “baby aspirin” (low dose aspirin often given to patients with problems of the blood vessels of the heart) should be discontinued about a week prior to the surgery.


Smoking increases the risk of developing a wound problem after surgery. We would strongly advise you to stop smoking a week before surgery, and to continue to refrain from smoking for the next few weeks after surgery.


Although you should be able to move around with a walker or a cane immediately after surgery, we would advise you to have a companion to help you for the next few weeks.


If your surgery is in the morning, you would often be admitted on the night prior to the surgery. If you would be operated on late in the afternoon, you would be admitted on the day itself. At times, patients may be admitted a few days prior to the planned surgery, especially if they have other preexisting illnesses that have to be treated first. Always ask your surgeon when he wishes you to be admitted. And do not forget to bring the admitting orders with you when you go to the hospital.

You have to fast (no food or drinks, even water, by mouth) at least eight hours before your scheduled surgery.

intheorOnce you are admitted, the anesthesiologist or a member of his/her team would visit you and go through the type of anesthesia that they propose to use. If you have any questions regarding the type of anesthesia to be used, now is the time to ask them. Oftentimes, a mild sedative is given to you in the room prior to transporting you to the operating room. Thus, you may not have the chance to ask your questions later.

About one hour before the planned procedure, the transport team will come and bring you to the operating room. If you have companions that decide to follow you to the operating room, they will not be allowed to enter the operating room itself due to patient safety issues.

Once inside the operating room, the anesthesiologist will administer the anesthetics to you. You will then be positioned for the surgery, and the procedure will commence after ascertaining that you are the correct patient and that we are operating on the correct limb.

The surgery may last from one and a half to two hours. For more difficult cases, it might last longer. A tourniquet is often applied on the upper part of the thigh in order to prevent excessive bleeding from the wound. At times, patients may feel a discomfort over this part of the thigh after surgery, and this is often due to the pressure exerted by the tourniquet on this part when it was inflated. During surgery, only the ends of the bones are replaced. The alignment of the knee is brought back to normal and the motion of the knee is improved. There are several implants in the market manufactured by different companies. Often, your surgeon will use the one that is most appropriate for you and the one that he is most comfortable with. After surgery, you will be brought to the recovery room. Your stay there may be anywhere from one hour to a few hours, depending on how fast you recover from the anesthetics. Thus, the total amount of time that you could be away from your room would be about 5 – 8 hours, depending mainly on how long you will stay in the recovery room.


recoveryrmWhile in the recovery room, you will notice several tubes attached to your body. You may have one or even two intravenous (IV) lines on your hands. You may have a urinary catheter to drain your urine. At times, you might also see one or two tubes draining excess blood from the wound. You will also note several wires attached to your body. These would include electrodes to monitor your heart and devices to measure your blood oxygen. Sometimes, a mask may be placed over your face in order to deliver additional oxygen to your lungs. There will be a lot of beeping sounds and blips from the various monitors around you. These devices are usually removed once you are transferred to your regular room. You will also note that immediately after surgery, both of your thighs and legs would be wrapped in elastic bandages. An alternative would be the use of a pair of tight-fitting stockings. These are designed to prevent blood clots from forming in your legs since you will not be as active as you previously were for the next few weeks. These stockings are worn for the next six weeks. If necessary, blood may be transfused at this time unless you have specifically indicated that you do not wish to receive any blood transfusion.

Some surgeons will put your operated limb on a device called a CPM, or continuous passive motion machine. This device slowly moves your knee from a fully straightened position to a bent position. Studies have shown that in the long run, there is no beneficial effect of this machine on knee motion when compared with physical therapy. The next day after your surgery, a rehabilitation medicine physician or a physical therapist may visit you. He/She will go over the proposed treatment plan that you will be doing. Physical therapy often starts on the day after surgery. If you were operated on in the evening, it would start on the morning of the second day after surgery. Therapy would consist of muscle strengthening, improvement of knee motion, and ambulation (walking) training.

The drains from the operative site are removed on the first or second day after surgery. The urinary catheter is also removed at about the same time. The intravenous lines are kept in place, usually to serve as a route for administration of antibiotics, pain relievers, or even blood (blood transfusion). Once these are not needed, the lines are removed.

The length of your hospital stay is dependent on several factors, including: presence or absence of other medical problems, condition of the surgical wound, progress of rehabilitation, and many others. In general, however, patients stay in the hospital for an average of five days.


Pain after surgery is managed by your anesthesiologist. If an epidural anesthetic was given, you may receive doses of pain medication through the epidural catheter at regular intervals. Another form of giving pain medication is through a patient controlled analgesia (PCA) unit. This device allows you to self-administer the pain medication by pressing a button. Later on, when all the intravenous lines have been removed, pain medication would be given by your nurse to you whenever you need it. If you feel the pain, please let our nurses know so that they could give you these medicines. There is almost no chance of addiction. In fact, it will be for the better since this would keep you comfortable and it would immensely help you make rapid progress with your therapy.


After 24 – 48 hours of intravenous antibiotics, some surgeons will continue giving you oral antibiotics. These are usually taken for two weeks. In addition, if you have any risk of developing blood clots in the veins of your legs, your surgeon might prescribe a blood thinner that would be administered, either orally or by injection, for the next few days.


Before you are discharged from the hospital, you will be instructed by your physician and your nurse on several things, including: wound care, medications, and activities. The wound has to be cleaned as instructed and demonstrated to you while you were admitted. Some surgeons prefer to have you clean the wound daily, while others would prefer less frequent dressing changes. The wound should not get wet until it has thoroughly dried. Most physicians wait until the skin sutures or staples are removed before allowing the area to get wet. Home medications would be prescribed. They should be taken as instructed by your physician, the nurse, or the hospital pharmacist. The anti-thrombotic stockings that you will be asked to use in order to decrease the risk of a blood clot developing in your legs should be worn for at least six weeks. Regular physical therapy is important. Before going home, make sure that you have spoken with your physical therapist regarding outpatient therapy. Regularly do the exercises that were taught to you while you were admitted. They are important in improving your knee motion and strength.

You will be allowed to go home when the wounds are dry, when you do not have a fever, and when you can move in and out of the bed with minimal assistance. Once walking strength and confidence have returned, you would be encouraged to move about more frequently. Not only will regular activities improve muscle strength, this will also lessen the risk of forming blood clots in the legs. Initially, you will have to use a walker or a pair of crutches in order to move around. But as you get stronger and your sense of balance returns, you will eventually be able to move about without the use of any assistive device.


If you notice any of the following signs or symptoms, please let us know as soon as possible.

  • Increasing pain and swelling in your calf or lower leg
  • Sudden shortness of breath or sudden onset of chest pain
  • Persistent fever
  • Increasing pain, warmth, redness, and swelling of the operated knee
  • Drainage coming from the operative wound

These are some of the warning signs that you may be developing a problem. Prompt treatment would lessen the chances of this getting worse.


In general, the following activities are allowed after a total knee replacement: walking, golfing, swimming, cycling, bowling, dancing, table tennis, and calisthenics. Repetitive, high-impact activities such as basketball, volleyball, and racquetball are not recommended. It would be better to discuss with your surgeon what physical activities you wish to continue or pursue after your surgery.


Article by Jose Fernando Syquia, M.D.
Advanced Orthopedics for Joint Replacement


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This 2015 AOJR wants to talk to you and your community about arthritis. Take part and join us in  promoting awareness about the social, emotional and health impact of arthritis as well as its evidence based treatments. Help us improve lives by creating awareness. You can contact us by calling 710-8292 or email us at 













October 2014. Dr. Paul Cesar N. San Pedro represented the Philippines in...





Who else but our patients can testify to AOJR’s expertise in joint replacement surgery and how we helped improve their lives. Here are what some of our patients have to say:


Alcera" After the operation, I thought I wouldn't be ableto enjoy the same lifestyle as I had before. I was wrong, It's amazing how I can still enjoy activites likes dancing and aerobics."

Doris Alcera, 63y.o. Total Knee Replacement, February 2011

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