Revision Total Knee Replacement Surgery

Revision Total Knee Replacement surgery replaces a non-functional knee implant with a new prosthesis. It is required if the patient has infection, instability, or stiffness in the knee joint after undergoing the primary knee replacement operation.
Revision Total Knee Replacement surgery comes in a variety of forms. Sometimes only one implant or prosthesis component needs to be changed. In other cases, the femoral, tibial, and patellar components must all be removed or replaced, and the bone surrounding the knee must be repaired using bone grafts.

Anatomy and Physiology of the Knee Joint

The knee joint consists of tendons, ligaments, muscles and bones, all working together to provide knee stability during movement.
The knee joint is a combination of three bones:

1. Thighbone(femur)
2. Shinbone (tibia)
3. Kneecap (patella)

The femur, patella and tibia surfaces are replaced with prosthetic implants during the primary total knee replacement.
In revision surgery, one or all of the three components - femoral, patellar and tibial - require removal, and the bone surrounding the knee must be reconstructed with augments.
After assessing the damage to the bone, the doctor will need to make a call regarding the usage of specialised implants with thick, larger stems that fuse deeper with the bone and give extra support.

As knee replacement revision surgery is performed for several reasons, its procedure may vary depending on various conditions. A few conditions treated with knee revision replacement surgery are:

1. Infection
2. Trauma or Fracture
3. Dislocation of the implant
4. Instability or stiffness of the knee

The doctor may recommend revision total knee replacement surgery for various reasons. Some reasons are:

1. People who have had a knee replacement at a young age and whose implants have deteriorated due to loosening or wear and tear
2. If the artificial joints have become infected causing stiffness and pain in the knee joint 
3. When the ligaments have been damaged, causing the implant to stop functioning properly, thus resulting in knee instability
4. Fractures around the knee joint

Typically, a knee replacement revision surgery involves 4 steps. These are:

1. Reshaping a bone
2. Eliminating bony fragments
3. Readjusting the original implant
4. Replacing the implant with a new one

The procedure of the knee revision replacement surgery is as follows:

1. At first, the surgeon follows the line of incision made during primary knee replacement surgery. However, the incision may be longer than the previous one to allow the removal of the old implant. 
2. After an incision, the surgeon exposes the knee joint by moving the tendons and kneecap aside. 
3. He/she then examines the soft tissues to rule out any possibility of infection. 
4. The surgeon also checks the metal and plastic parts of the implant to identify the worn-out or loosened parts.
5. If required, the whole implant and cement (used in the primary knee replacement) are removed while saving as much bone as possible.  
6. Once the implant is removed, the surgeon prepares bone surfaces for revision implant.
7. In case of significant bone loss around the knee, metal augments and platform blocks are added to the main implant components to compensate for the bony deficits. 
8. In rare cases, bone graft materials are required to rebuild the knee. The surgeon may take the graft from the patient’s bone (autograft) or a donor (allograft). 
9. Finally, the surgeon inserts the revision implant, repairs the surrounding soft tissues if damaged and checks the motion of the knee joint. 
10. A drain is placed to extract fluids and blood from the knee joint that may remain after the surgery. 

Prior to the revision knee replacement surgery, the surgeon will discuss and prepare the patient for the surgery. These steps often involve:

Before the Surgery

1. The patient needs to reveal information regarding all the medicines he/she has been taking, including non-prescription medicines such as Aspirin.
2. Blood thinners, including certain anti-inflammatory medicines and vitamin supplements, should be avoided before the surgery as per the doctor’s advice, as they can increase bleeding. 
3. The doctor takes imaging tests like an X-ray to examine the area around the knee implant. It also helps in determining if the implant has loosened up or dislocated. An X-ray can also identify the presence of bony fragments. 
4. An MRI or CT scan is sometimes required to identify any tissue damage which is not visible in the X-rays. 
5. The doctor takes the patient’s blood test to rule out the possibility of an infection.
6. In some cases, knee aspiration is also required to diagnose a joint disorder. Aspiration is the procedure to extract fluid from in and around the knee joint. 

On the Day of Surgery

An anesthesiologist evaluates the patient to determine if he/she would require general or regional anaesthesia. General anaesthesia is induced to put the patient to sleep during the surgery, whereas regional anaesthesia only numbs the body from the waist down while the patient remains awake.

The length of the recovery varies from person to person. Sometimes, patients recover from the revision knee surgery sooner than the primary surgery. In some cases, the recovery is slower. It may take upto twelve months to recover fully. However, people resume their normal activities after six months, which doesn’t include physically strenuous activities or exercises. 

Recovery process at the hospital

1. The health care providers shift the patient to a recovery room to monitor the vitals and the after-effect of anaesthesia. 
2. Once the effect of anaesthesia wears off, the patient is transferred to a hospital room where he or she must stay for several days.  
3. Pain and discomfort are not uncommon after the surgery. Healthcare providers give pain-relieving medicines for faster recovery. 
4. The doctor or a physical therapist suggests specific exercises to strengthen the leg and restore the range of motion. 
5. Foot and ankle movement is encouraged immediately after the surgery to prevent blood clotting.
6. The doctor can also recommend reducing blood clotting in the leg with compression stockings, inflatable leg coverings (compression boots), and blood thinners. 
7. The doctor may also prescribe antibiotics before and after the surgery to prevent infection.

Recovery process/ expectation after hospital discharge

1. The site of the incision is to be kept clean and dry.
2. The patient must follow specific bathing instructions to avoid water touching the incision site. 
3. He/she must do regular exercises as instructed by the doctor to improve the strength and mobility of the knee joint. One of the common exercises is straightening the leg and then bending the knee to at least 90 degrees of flexion. 
4. If the doctor has advised the use of crutches or cane, the patient must ensure their use until he/she feels comfortable walking without assistance.

First Follow Up Appointment

Usually, the patient visits the doctor two weeks after the surgery or as per the instructions. During the appointment, the doctor examines the incision to ensure the wound is healing properly. He/she gives follow-up instructions regarding the removal of sutures or stitches. The sutures beneath the skin need not be removed as they dissolve on their own.

The knee replacement revision success rate is high and has a lower failure rate. The benefits of knee replacement revision surgery include:

1. Relief from chronic knee pain and swelling
2. Increased mobility resulting in an active lifestyle
3. High success rate and satisfaction

Revision knee surgery being more complex than primary knee surgery, bears a greater risk of complications. The doctor discusses the potential risks and takes substantial steps to avoid possible complications. These complications may include:

1. Blood clots in the legs or lungs
2. Infection in the new implant
3. Improper healing of the wound
4. Loosing of the new implant (its risks are higher if the patient is overweight)
5. Dislocation of the new implant 
6. Bone fracture during the surgery while removing the implant
7. Joint infections may lead to the formation of a bone at the lower end of the femur. This process is known as heterotopic ossification.
8. Damage to the blood vessels or nerves

When to Consult a Doctor

1. Bleeding from the incision site
2. Swelling or redness around the incision site
3. Fever or chills
4. Increased pain even after taking pain-relieving medicines

Delaying a knee replacement revision surgery procedure can increase the severity of the pain leading to reduced quality of life. Below mentioned are some of the common risks of delayed knee replacement revision surgery:

1. Instability in the knee joint
2. Reduced function in the knee
3. Aseptic loosening (failure of the joint implant) leading to the degeneration of the bone tissue

The cost of a knee replacement revision surgery ranges from ₹3,00,000 to ₹5,00,000. The cost varies based on the following factors:

1. Type of revision total knee replacement surgery
2. Age of the patient
3. The medical condition of the patient
4. The type of hospital facility availed - individual room or shared.

Procedure Name	Cost value
Revision Total Knee Replacement Surgery	₹3,00,000 to ₹5,00,000