Knee Replacement
The knee, also known as the tibiofemoral joint, is a hinge joint where the thigh meets the lower leg and provides motion. It is one of the most frequently damaged joints. An injury, arthritis, or any inflammation in the knee can result in severe knee damage, causing progressive pain, impaired function, difficulty walking or climbing stairs, etc. When nonsurgical treatment methods and walking aids fail to alleviate the symptoms, an orthopaedist will consider a surgical treatment method called knee replacement surgery to relieve pain and help you resume normal activities.
What is knee replacement surgery?
Knee replacement surgery is the procedure to replace the damaged or diseased weight-bearing bones and cartilage of the knee joint with artificial materials or implants. These implants are made up of long-lasting metals, plastics, or ceramic materials that mimic the movement and function of a healthy human knee.
Knee replacement procedures typically fall into one of two categories:
- Total knee replacement is when both sides of your knee joint are replaced.
- Partial knee replacement: only one side of your joint is replaced.
Why is knee replacement surgery recommended?
A surgical knee replacement is recommended for patients whose knee joints have been damaged by progressive arthritis, especially osteoarthritis, trauma, or other rare destructive diseases of the joint.
Those who require knee replacement surgery frequently:
- Severe pain, swelling, and stiffness in the knee joint that limits your everyday activities.
- Difficulty walking and taking care of themselves.
- Knee deformity (the knees may turn outward or inward)
- Symptoms that do not improve with conservative nonsurgical treatments.
What is the pre-procedure care for knee replacement surgery?
Your orthopaedic surgeon will carry out certain tests, like a physical examination and imaging tests like X-rays, MRI scans, etc., to confirm whether knee replacement surgery is the best method to improve the condition. Once the surgeon decides to perform a knee replacement surgery, you have to follow certain instructions to avoid risks and complications during the procedure and recovery.
A few weeks prior to surgery:
- A complete medical checkup is recommended to assess your overall health. Routine blood and urine tests are carried out for signs of infection. Chest X-rays and EKG studies are also carried out to check for any significant heart and lung disorders. If you have diabetes, heart disease, or other medical conditions, surgery will be conducted only when these conditions are controlled.
- You may have to temporarily discontinue or modify some medications that may interfere with the procedure and recovery, which may include aspirin, warfarin, ibuprofen, and methotrexate.
- An obese patient (greater than 200 pounds) should maintain a healthy weight before the procedure to avoid excess stress on the knee joint during recovery.
- Your healthcare team may ask you to donate blood before the surgery for blood transfusions during the knee replacement surgery (if needed).
- You should avoid drinking and smoking, as they will slow down wound and bone healing.
- You will be referred to a physiotherapist, who will help you strengthen the muscles and increase the flexibility of the joint through some conditioning exercises.
- As you will need extensive care and support after the surgery, your healthcare team will recommend that you arrange for someone to assist you at home.
A day prior to surgery:
- Before the treatment, you won't be allowed to eat or drink anything for six to twelve hours.
- The anaesthesia team will evaluate you to determine the type of anaesthesia that is best for you. The procedure is generally carried out either under general anaesthesia (which puts you to sleep) or spinal anaesthesia (which numbs your body from the waist down).
How is knee replacement surgery performed?
A total knee replacement generally requires between one and a half and three hours. Before the surgery, you will be moved to the operating room and placed in a bent position in order to expose the joint. Once you are in position, anaesthesia will be administered by the anaesthesiologist.
The surgeon will make a deep incision (6-10 inches) and move the kneecap aside. Cut and remove the damaged joint surfaces. The artificial implant is then shaped accordingly and fitted well in the right position. The artificial implant contains a curved metal piece that replaces the end of the thigh bone, a flat metal plate that replaces the shin bone, and a plastic space between these metal pieces that acts as cartilage.
Once the implants are properly fitted in the right position, the incision is closed with either stitches or clips, and the injury is dressed.
What is the post-procedure care?
After the surgery, patients are shifted to the recovery room until the effects of anaesthesia wear off. The team will continuously monitor the vitals. An X-ray image is taken after the surgery to confirm the position of the implant. The post-procedure care at the hospital may be as follows:
- Medicines: Medicines are prescribed for short-term pain relief and to prevent the formation of blood clots.
- Physical therapy: The physiotherapist will teach exercises to strengthen the muscles and restore knee movements. The patient should begin moving the new knee joint 48 hours after the surgery.
- Supportive devices: A knee support called a continuous passive motion (CPM) exercise machine is used to move the knee through various angles and restore the range of motion for hours while the patient relaxes.
A catheter may also be inserted into the urethra for patients who have trouble passing urine after the surgery.
After the surgery, you will be discharged in a couple of days. Before being discharged from the hospital, your surgeon will give you some measures to be followed at home for a speedy recovery:
- Use a cane, crutches, or walker for the first few weeks after surgery until your balance, flexibility, and strength have improved.
- Keep your bandages and surgical dressings clean and dry to avoid infections.
- Follow a balanced diet rich in iron, which aids in faster wound healing and in restoring muscle strength.
- Exercise regularly, as instructed by your physical therapist.
Most people can stop using walking aids around 6 weeks after surgery and return to normal activities after 6-8 weeks post-surgery.
Outlook
Knee replacement surgery provides excellent results in relieving pain, restoring normal knee movements, and improving quality of life. Most patients can return to normal activities after recovering from knee replacement surgery.
A physical therapy programme along with home exercises should be continued during the recovery period. Everybody recovers at their own rate.
The typical lifespan of a prosthetic knee joint is 10 to 15 years. A follow-up is necessary once a year to evaluate the functioning of the device. If you undergo knee replacement surgery at a young age, you may need a second surgery to replace the deteriorated implant.