What exactly is a knee replacement?
It is a surgical technique by means of which the contact surfaces of a joint, in this case the knee, are completely or partially replaced by prostheses made of materials that are highly resistant to wear and tear.
Knee prostheses are manufactured with resistant materials that are suitable and compatible to be in contact with the human body.
The materials and prostheses used have advanced a lot in the last years, offering better results and less wear of the components. These basically consist of highly cross-linked polyethylene, titanium and cobalt-chromium.
In which cases is it indicated? When should it be placed?
In general, we recommend conservative treatment initially, using anti-inflammatory medication, light impact activities (walking, cycling, swimming), physiotherapy sessions and, in some cases, intra-articular injections with cortisone derivatives, hyaluronic acid, growth factors or stem cell concentrate will be required. When all this fails and pain considerably limits the patient’s activities is when we think of surgery.
How is the intervention performed to place a knee prosthesis?
Knee joint replacement surgery requires hospitalization for a period of 3 to 5 days. You will not feel any pain during the surgery.
You will be given one of two types of anesthesia:
- General anesthesia: you will be completely asleep during the entire procedure.
- Regional anesthesia (intradural or spinal): a medication is applied to your back to numb you from the waist down. Sedative medication is also used. You may have temporary amnesia and not remember the procedure, even if you are not completely asleep.
After you are given anesthesia, the surgeon will make an incision over your knee to open it. This cut is often 20 to 25 centimeters long.
Then cuts are made through specific guides at the level of the femur, tibia and patella. The pieces that will replace the joint are then fixed with cement.
Once the joint is replaced, usually with metallic pieces in femur and tibia that are articulated with a polyethylene (high density plastic) in the middle, the stability and proper functioning is checked and the skin is closed with sutures and staples. Sometimes a drain is left in place for 24-48 hours to avoid hematomas. The surgery usually takes about 2 hours.
Post-operative protocol for a knee replacement
Knee replacement surgery will require physiotherapy and rehabilitation so that the knee joint can regain strength and general mobility starting within 24 hours after surgery.
It is important to follow the prescribed protocol and closely follow the instructions provided by your physical therapist and treating physician. Initial therapy focuses on safe movement with certain restrictions for 6 weeks.
The convalescence period is usually 3-4 months, after which patients will be able to function properly in most activities of daily living.
How to care for the knee prosthesis after surgery?
Patients can lead a normal pain-free life with moderate sporting activity. This means that they will be able to walk, swim, ride a bicycle, ski, etc.
However, high impact and high speed sports such as soccer, running, and risky sports may be limited, since they generate a greater impact on the joints and may affect the results of the surgery.
It is always advisable to consult with your orthopedic surgeon to have a clear idea of how your lifestyle will be affected after a surgery of this type, although the impact is usually positive, since it corrects problems that cause pain and limit daily life and physical activity.
The average lifespan of an implanted prosthesis without complications will be between 15 and 25 years.