What is Total Knee Replacement?
When the arthritis is severe and the pain management is not adequate with non-operative treatments, eventually a total knee replacement may need to be carried out. In this procedure, the entire joint is replaced with metal and high-density plastic and the prosthesis is usually cemented into your bone. The operation generally takes about 1-1.5 hrs, and it involves a 2-3-day hospital stay. Patients can put full weight on the limb after surgery, but they have to use crutches or a walker for several weeks after the operation. Full recovery after this procedure generally takes 3-4 months, but patients may notice ongoing improvement for over one year after surgery.
Results
The operation is primarily done to help relieve pain from arthritis. A total knee replacement will also improve alignment and stability of the joint. The success rate is very good, and 80-85% of patients generally notice good pain relief. It is quite common to experience some pain even after a total knee replacement. However, most patients are happy after surgery, and they feel “better” than before the operation. With the modern knee replacements available 90% of knee replacements are still functioning 15 years after they were implanted.
The operation general improves motion of an arthritic knee but restoration of normal knee motion is uncommon. Full bending to allow for kneeling on the floor is uncommon. Numbness around the incision and on the front of the knee on the lateral (outside) of the incision is normal after a knee replacement. It is normal to hear and feels some knocking with motion of a knee replacement as the components slide against one another. You may set off airport security and may be required to discuss your knee replacement with security.
15-20% of patients are not entirely happy with the operation. Sometimes the patient does not achieve as much pain relief as they were expecting or they do not achieve the function they were hoping for. With knee replacements, sometimes we cannot understand why certain patients do not achieve the same success as others. Luckily, the majority of patients are quite satisfied with the final result.
Post Operative
A total knee replacement can lead to quite a bit of pain after surgery. This is normal. Narcotic type medications are prescribed while in hospital and these are continued post-operatively. It is useful to combine the narcotic medications with acetaminophen.
Swelling and bruising are quite common after surgery. Some patients notice bruising up and down most of the limb. This needs to be watched closely, but it is generally normal. Icing can help with pain management and it can help control the bruising.
A cryocuff is a device that helps circulate ice water through a wrap around the knee. Many patients use this device to help manage pain and swelling after surgery. You can pre-purchase a cryocuff if you call your surgeon’s office. This way, it can be applied immediately after surgery to help control the swelling and pain. There is good research documenting the positive effect on pain relief of cryocuff treatment after surgery. There are different types of units available ranging from $200-$400. Most extended health care plans will cover the majority of the cost.
After surgery, the physiotherapist will work with you to get you up and walking as soon as possible. If your surgery is done earlier in the day, you may start mobilizing that same afternoon. Otherwise, work on mobility will generally start the following morning. You will use crutches or a walker to help you mobilize after surgery.
Patients generally stay in hospital for 2-3 days after surgery. Discharge will occur when the patient has met their mobility criteria. The decision to discharge a patient involves input from the physiotherapists, nurses and doctors.
Upon discharge, you will be given a booklet with exercises you can carry out yourself at home. The staples are removed 10-14 days after surgery. Physiotherapy will continue as an outpatient after the wound has healed and the staples are taken out. Outpatient physiotherapy can be carried out at a hospital closer to home. It does not necessarily need to be done at Lions Gate Hospital. The physiotherapist in the hospital will discuss outpatient physiotherapy with you while you are still in hospital.
Wound care: It is important you keep your wound dry until it is healed and the staples have been removed. The nurses will apply a waterproof dressing on your wound, and they will give you instructions on changing the bandage if necessary. You can make an appointment to see your family physician or surgeon in order to have the staples removed. Many patients who live further away from Lions Gate Hospital choose to see their family physician for staple removal. It is very important that the incision is dry when it is time to remove the staples. If there is ANY drainage after 10-14 days, it is important you notify your surgeon’s office immediately. This drainage can be a sign of an early infection, and it needs to be treated aggressively. Antibiotics are generally not useful when treating these post-operative infections.
Follow-up: After discharge, you will see your surgeon or family physician at 10-14 days after surgery to remove the staples. The next follow-up with your surgeon is generally 6-8 weeks after the surgery date. Subsequent follow-ups vary depending on your surgeon’s pattern of practice.
By 6-8 weeks after surgery, your surgeon will generally expect at least 90 degrees of flexion in the knee. If there is insufficient flexion, your surgeon may discuss the possibility of performing a manipulation of your knee under anesthetic. During this procedure, the surgeon bends your knee while you are given an anesthetic in the operating room, and this breaks down scar tissue and helps improve the range of motion. This procedure is not required very often.
Long-term Results: A total knee replacement will generally last 15-20 years. However, there is no guarantee how long the prosthesis will last. Some fail earlier for various reasons so it is important to investigate any change in symptoms to ensure there are no signs of early failure. Your surgeon may recommend routine x-rays at various periods to assess the prosthesis and watch for early signs of loosening.
Activity Level: Patients are encouraged to remain active after a total knee replacement. However, the prosthesis is not designed to allow participation in impact type sports. Prolonged running is generally discouraged after a knee replacement.
After surgery, patients can walk, hike, bike, and swim. Lighter impact sports such as golf, doubles tennis and light skiing can be done as well. It is important to maintain a good fitness level after total knee replacement. Talk to your surgeon about activities that you may want to try.
Risks or Complications
Although most patients do well after total knee replacement, there are risks after this surgery.
Infection: This is a devastating complication after joint replacement. It occurs in about 1% of cases. However, there are higher rates of infection associated with diabetes, obesity and any condition or medication that weakens your immune system (rheumatoid arthritis, prednisone, etc).Prior to surgery, it is important to do everything you can to lower the risk of infection. It is important to maintain good nutrition. A malnourished patient has a higher chance of infection. If you have diabetes, the blood sugars need to be controlled properly for several months prior to the surgery. The skin and soft tissues need to be healthy, particularly around the area where the incision is going to be made. If there are bad cuts or scrapes in the surgical area, your procedure will be cancelled.During the operation, everything possible is done to minimize infection risk. Patients are given antibiotics prior to the surgery. All equipment is sterilized and the operating room personnel wear sterile gowns. Special surgical preps are used to sterilize the skin on the limb as well.
Bleeding: There will be blood loss due to the surgery. This is watched closely while you are in hospital. If the hemoglobin levels (blood counts) become too low, a blood transfusion may be necessary. Your doctor will decide if you need a transfusion after surgery. In general, less than 10% of patients require a blood transfusion.
Nerve injury: A nerve injury after surgery could affect the movement of the foot. Luckily, this significant complication is extremely rare. If it does occur, it will generally be observed. Nerve function generally returns, but it can take several months. A permanent nerve injury is quite rare.It is quite common to notice numbness on the outer half of the incision after surgery. Most patients experience this skin numbness. It does get better with time, but it is not uncommon to have a permanent numb patch in the future. This is not usually bothersome at all. However, some patients notice discomfort and hypersensitivity from this numb area.
Stiffness: It is very important to work on range of motion exercises after a knee replacement. Physiotherapy is done to help improve motion after surgery. However, most of the exercises need to be done by the patients themselves. It takes a great deal of hard work to achieve a functional range of motion after surgery. By six weeks after surgery, your surgeon will generally expect at least 90 degrees of flexion.If the motion is not progressing, your surgeon may sometimes recommend a manipulation of the knee. In this procedure, you come into hospital and receive an anesthetic. The surgeon then flexes the knee while you are asleep in the OR, and this helps break down scar tissue and helps improve motion faster. Physiotherapy resumes after this manipulation is carried out. It is uncommon to require a manipulation of the knee after surgery.
Loosening: The total knee replacement prosthesis has a limited lifespan. The surgeon generally expects the prosthesis to last about 15-20 years. However, there is no guarantee how long the prosthesis will last. Sometimes, the prosthesis will fail or loosen early so it is important to obtain periodic radiographs.
Blood Clots: Blood clots can occur after a total knee arthroplasty. They can be very serious, particularly if they travel to the lung (pulmonary embolism). The best way to prevent them is to move around as much as possible after surgery. You will also receive medications to help prevent blood clots. These medications can be injected daily and there are others that can be taken orally. After a knee replacement, you will likely receive medications to prevent blood clots for approximately two weeks after surgery.It is normal to experience swelling in the leg after surgery. This should gradually improve as time goes on. If the swelling seems excessive or continues to worsen after surgery, you should be investigated for the presence of a blood clot. An ultrasound of the limb is done to look for a blood clot.If you develop any chest pain or shortness of breath after surgery, this could be related to a blood clot that has gone to your lung. This constitutes an emergency and should be investigated right away. You should go to your local emergency department immediately if this occurs.
Chronic pain: Most patients notice improvement in pain after surgery. However, it is not uncommon to experience some pain even after a well done knee replacement. Most patients feel the pain is much less than what they experienced before the operation, and they are satisfied with the result. However, 15-20% of patients experience more pain than they were expecting and some people can be unhappy after their knee replacement.