Minimally Invasive Total Knee Replacement
Minimally invasive total knee replacement surgery is a specific approach to the knee that minimizes surgical trauma to soft tissues by decreasing the length of the incision and disruption to muscle groups. There is minimal splitting of muscles that takes place during this procedure. These measures theoretically allow for less post-operative pain, shorter recovery, and a faster return to function. Dr. Adam Rana is one surgeon in New England that performs this procedure. Dr. Rana completed his Orthopedic Surgical Residency at the Boston Medical Center and Lahey Clinic. After residency, he completed a fellowship in Adult Reconstruction, Arthritis, and Joint Replacement Surgery at the Hospital for Special Surgery (HSS) in New York City. This institution was voted the #1 rated Orthopedic Hospital in the nation according to US News and World Report. While at HSS, Dr. Rana trained under several world renowned orthopedic surgeons including Drs. Chitranjan Ranawat, Thomas Sculco, and Eduardo Salvati.
By utilizing the minimally invasive technique and a sophisticated anesthesia protocol, patients typically are up and walking without significant pain a few hours after surgery, take minimal pain medications post-operatively, and are home comfortably two to three days after surgery. The time to which patients are back to work is also faster than with the traditional knee replacement. Patients with desk type work can return two to six weeks after the procedure, while patients with more physically demanding jobs can return between six to twelve weeks after surgery. The implants used with this procedure are the same ones used with traditional knee replacements.
Who Is A Suitable Patient for Total Knee Replacement?
Patients who have disabling pain in the knees as the result of arthritic involvement are, as a rule, candidates for replacement of the knee joint. Many measures will generally be tried before the decision is made to perform the knee replacement. The use of exercises, anti-inflammatory medication and injections into the knee may be tried prior to surgery. In the patient who has advanced arthritic changes in the knee, the function of the knee is inadequate, and pain will be felt when walking, and many times while at rest. Deformity of the knee will also frequently result, and the patient may notice that the knee is becoming bowed or knock-kneed. Stiffness and swelling may also be present in the patient with the arthritic knee.
How Is the Operation Performed?
Just as when a tooth is decayed the dentist will remove the decayed area and cap the tooth, so also in the knee the arthritic ends of the knee joint are removed and the ends of these bones are then covered with a metal piece for the femur (thigh bone) and a plastic piece is used with a metal reinforcing tray on the tibia (lower leg bone). Since the knee cap is also commonly involved in the arthritic knee the back portion of it is also resurfaced with a plastic piece. The prosthesis will then be moved by the muscles and ligaments that normally move the knee. The joint will be lubricated by the same synovial fluid that lubricates the normal joint.
It is necessary to prevent the prosthesis from moving as they cover the ends of the bone and therefore bone cement is used to hold the position achieved when the prosthesis is inserted. This material has been used for over 50 years in the body and has proven to be an excellent material in maintaining the fit of the various pieces of the knee replacement.
What Is the Usual Procedure for Total Knee Replacement?
After the decision has been made to perform a total knee replacement on a patient the operation time will be scheduled, and the patient will be admitted to the hospital the morning of their surgery. Patients will undergo Pre-Admission Testing prior to admission to the hospital, and this is generally performed a few weeks before admission to the hospital. A very careful analysis is made of blood, urine, and electrocardiogram at the time of the Pre-Admission Testing and this permits a review of all laboratory tests prior to actually being admitted into the hospital. Should any test come back abnormal it can be looked into in plenty of time prior to the patient’s actual admission to the hospital.
An anesthesiologist will see you prior to surgery and explain the options you have with regards to the operation.
The operation itself takes about 1½ hours and you will be brought to the recovery room after surgery is completed.
An intravenous line will be maintained for 24 hours to allow administration of fluids and antibiotics after surgery.
Most patients are out of bed a few hours after surgery and begin to walk with a walker. The therapist will also begin increasing your exercises and bending during this period. As you continue to improve you will be advanced to a cane.
The First Month at Home
After discharge from the hospital many patients will experience some fatigue their first few days at home. This is common and should not alarm you but encourage you not to overdo your activity at the outset. It is important, however, to walk and use the knee as much as is comfortable. Also, you must work on the exercises given to you prior to going home. These include strengthening and bending exercises. We will arrange for a therapist and nurse to visit you at home two or three times a week to ensure that your recovery remains smooth and that your knee is functioning well.
You will return to the office two weeks after discharge from the hospital. An X-ray of the knee will be taken, and the bandage and staples will be removed during the first visit after surgery.
First Six Months After Surgery
Most patients will continue to improve up to six months after total knee replacement. Patients will generally begin giving up the cane at 3-4 weeks after surgery and knee motion will continue to improve as the scar tissue about the incision becomes more mature and swelling about the knee becomes less. The redness and warmth about the incision will also reduce with time. It is important to use the knee by walking and exercising to maintain knee motion. Athletic activities such as swimming, hiking and golf are excellent for the knee recovering from replacement surgery. Walking, however, remains the best exercise and should be done daily. Running and jumping activities following total knee replacement reduce the longevity of the knee and should be avoided.
Long term results now looking at patients in whom totals knee replacement was performed 20 years ago continue to demonstrate good to excellent results in the majority of patients. The results are particularly encouraging in view of the improvement in surgical technique and implant design that we are currently using.
What Are the Risks with Total Knee Replacement
- Medical
A patient after total knee replacement may have a medical complication. This can be of any type and include heart problems, lung problems including a blood clot, or phlebitis in the operated leg. If the patient has a medical history for a particular problem this may be aggravated after surgery. We will review all medical conditions during the Pre-Admission Testing. Medical complications are for the most part uncommon but can occur and you must be aware of this possible problem. - Infection
The most catastrophic problem that can occur to the knee after replacement surgery is infection. This can occur in the immediate post-operative period or be delayed. We operate at Maine Medical Center in operating rooms with a laminar flow system of air flow to reduce contamination in the operating room. We also use space suite type operating suits to prevent interchange of exhaled air between the operating room team and the operated area.
Even so, infection does occur in less than one percent of our patients and should the infection be deep around the prosthesis it is necessary to remove the infected implant and treat the patient with a prolonged course of intravenous antibiotics (up to 6 weeks). At that time, we are generally able to put the knee back into place. Our results with this technique (re-implantation of the knee after infection) have been very successful to date.
After any implant surgery it is important that you receive antibiotics prior to any procedure which might introduce bacteria into your bloodstream. This includes such procedures as teeth cleaning, extraction’s or extensive gum work, urinary manipulations such as cystoscopy or vaginal or colonic surgery. Any infection that you have come down with should be treated aggressively with antibiotics. If you have any questions regarding this always bring it up with your treating physician or please contact the office. - Mechanical
This refers to problems related to the prosthesis itself and includes such areas as breakage, loosening, and wear. The incidence of failure of the prosthesis in patients with total knee replacement has been extremely low. The most common source of failure when it does occur is loosening of the bond between the prosthesis, bone, and the bone cement. This can result in pain and shift in the position of the replacement and in severe cases may require revision knee replacement.
The incidence of loosening has been extremely low and is in the area of less than five percent in long term follow up. Wear and breakage has been an insignificant problem to date.
Summary
This is designed to give you an overview of what it entails to have your arthritic knee replaced and what you can expect in recovery and long-term function of this knee. Results have been very encouraging, and the longevity of the prosthesis appears quite good. There is always the chance that a complication can occur and those that are listed are general ones and do not include an entire list of possibilities. The incidence of these complications is low, and we do many things to prevent them but still the patient must be aware that they can occur and may influence recovery.
We have performed thousands of total knee replacements at Maine Medical Center and feel it has provided the disabled patient with a painful, arthritic knee with excellent return of function and the ability to return to a more comfortable and productive life.
