Total Knee Replacement
TOTAL KNEE REPLACEMENT DEFINITION
The ends of the femur (thigh bone) and the tibia (shin bone) make up the knee joint. The two are covered by cartilage which is very smooth and allows the bones to glide over each other during movement. The knee cap, (the patella) also forms part of the knee joint and is held in position by tendons.
Should the cartilage be damaged, such as by injury or arthritis, pain and restricted movement is experienced as the bones rub directly on each other.
In the total knee replacement procedure, the damaged surfaces are removed and replaced with an artificial joint which has plastic and metal components.
The goal of the surgery is to replace a painful, deformed and stiff joint with a pain-free, well-aligned and easily moving joint.
THE ACTUAL SURGERY
The operation should last 1-2 hours using either a general or spinal anaesthetic. An incision is made over the front of the knee. The damaged portion of bone is removed using precision instruments to ensure that the minimum amount of bone possible is removed.
The knee replacement implant is then temporarily inserted to “trial” the implant. This allows the surgeon to ensure that the implant is fitting perfectly prior to the final implant being inserted. Once any minor adjustments have been made to ensure optimum fit, movement and function, the final knee implant is inserted and fixed into place using bone cement. The wound is closed using or skin clips with a dressing and circumferential bandage to cover this.
After the surgery, you are transferred to a recovery room before eventual transfer to the ward. You will have intra-venous fluids administered using a drip in the arm. Blood tests are completed the next day and depending on the results, very occasionally, a transfusion may be needed in the post-operative period. X-rays are completed the following day done to show the position of the implant.
The amount of pain relief needed after the surgery vary from one person to the next. Hence a patient specific pain regimen is administered.
AFTER-OPERATION PHYSICAL ACTIVITIES
Physiotherapists often start mobilising exercises hours after surgery. Full weight may be put on the affected knee straight away; however, you will likely require addition support. Most patients are normally ready to be discharged within 2-3 days.
HOME CARE ADVICE
After the surgery, you will feel some pain, but it is likely to be minimal as compared to the pain felt prior to the surgery. This may last from a few days to several weeks and it is important to take pain-killers as prescribed.
The swelling and bruising that is experienced usually last between 6 and 8 weeks but may even last up to half a year.
2 weeks after the surgery, the skin clips used to close the wound may be taken out. It is usually safe to bathe at this point; however, you should follow the doctor’s recommendations.
A follow up appointment is arranged approximately 6 weeks after the operation. Activity needs to be increased gradually by walking daily and exercising. It is often recommendable to stay away from gardening, sporting or driving activities until you are cleared by the doctor to do so.
Even though it is highly successful, there are a number of risks.
The anaesthetist will go through this with you in more detail.
A small risk of joint infection after the procedure exists. To prevent infections, antibiotics are usually administered during the operation. Some of the symptoms of infection include pain, swelling, redness on the wound, and even fever. Contact your doctor as soon as you detect these. There is also a small risk of chest and water work infections.
Deep Vein Thrombosis/ Pulmonary Embolus
Acute pain on the calf is often a sign of blood clot in the vein. Shortness of breath/ chest pain are typical symptoms of a pulmonary embolus. Support stocking and medication to prevent these symptoms are given following the operation and need to be taken for 2 weeks post-surgery.
There is the risk of the knee loosening or wearing out over time.
Damage to blood vessels or nerves can also occasionally occur following knee replacement surgery. This is rare complication but something you need to be aware of.
Close surveillance is advised so that possible problems are detected early and dealt with. A knee review program is used to assess how the artificial knee performs.