Partial vs total knee replacement surgery: Which fits better?
Joint replacement surgery has evolved extremely over the past few decades, giving thousands of patients all around the world, a second chance at life. Today, patients suffering from painful conditions such as osteoarthritis of the knee can take back control of their life and live pain-free thanks to options such as total or partial knee replacement.
As knee replacement surgery is generally an elective procedure, patients have the time to do a comprehensive research before taking any decision and scheduling the procedure. One of the decisions they wrestle with is choosing between total or partial knee replacement surgery. Before we dive into the pros and cons associated with each, let us understand these two procedures better.
Total knee replacement surgery
Total knee replacement surgery is also called knee arthroplasty or simply knee replacement. It is a surgical procedure performed to repair a damaged knee. The knee joint can be damaged by trauma/injury or conditions such as osteoarthritis. In this procedure, the damaged bone and cartilage from the tighbone, shinbone and kneecap are replaced with a prosthesis or artificial joint made of metal alloys, high-grade plastics and polymers.
A typical knee replacement surgery generally lasts for about 2 hours. Intravenous antibiotics are administered to the patient before, during and after the procedure to prevent infections. During the surgery, the patient will be given a general or spinal anaesthetic.
The knee is kept in a bent position to expose all surfaces of the joint. The surgeon then makes an incision about 6 to 10 inches long. Through this incision, the surgeon moves the kneecap aside and cuts away the damaged joint surfaces.
Once the joint surfaces are adequately prepared, the surgeon attaches the pieces of the prosthetic joint. The surgeons test the new knee joint by bending and rotating it before closing the incision.
After the procedure, the patient is placed in the recovery room for 1-2 hours. They are generally discharged a few days after the procedure. It is important in the first few days post-surgery to move the foot and ankle. This increased blood flow in the leg which reduces the risk of blood clots and DVT. Patients have also prescribed blood thinners and compression boots to further prevent swelling and blood clots.
Knee replacements generally provide patients with pain relief and greater mobility. Artificial joints can be expected to last more than 15 years. The lifespan of the artificial joint depends on the quality of surgery and care taken after surgery.
Partial knee replacement surgery
Partial knee replacement surgery or unicompartmental knee arthroplasty offers an alternative to patients with damaged knees if the damage is confined to a particular compartment of the knee.
Earlier, this procedure was generally performed on older patients as they were unlikely to overexert themselves. Today, partial knee replacement has risen in popularity even in the younger population as it has a lower recovery time as well as decreased post op pain.
However, this surgical alternative is not suitable for everyone. It is estimated that about 5%-6% of patients with arthritis of the knee are eligible for partial knee replacement surgery.
This procedure can be performed on patients having medial or lateral knee osteoarthritis. “Medial” is the inside compartment of the knee, closest to the opposite knee, while “lateral” refers to the outward compartment which is farthest from the opposite knee.
In order to determine if the patient is a suitable candidate for partial knee replacement surgery, the surgeon will:
- Ask the patient to identify the painful region in the knee, check the stability as well as the range of motion in the knee. As X-ray scan can help determine if the damage is confined to any one or both compartments of the knee.
- The patient must have an intact anterior cruciate ligament, sufficient range of knee motion, damage confined to only one compartment and stability in the joint. The angulation of the deformity is also considered to decide the suitability of the procedure.
Partial vs total knee replacement
“What are the benefits of a partial vs total knee replacement?” This is one of the most frequent questions posed to orthopaedic surgeons everywhere.
To find an answer to this question, we must first understand why the need for surgery arises. Patients develop knee joint degeneration due to a number of reasons. It can be a result of any past trauma, bad outcomes of previous surgeries, infection, rheumatoid or inflammatory arthritis, childhood diseases, obesity as well as aging.
The knee joint has a cartilage that helps remove friction and distributes the joint forces uniformly. It also helps cushion the forces, acting like an effective shock absorber. With knee degeneration, this cartilage deteriorates, resulting in joint pain and decreased function.
The knee joint is broadly divided into three compartments. These are:
- The medial compartment (inside of the knee, closer to the opposite knee)
- The lateral compartment (outside of the knee, further from the opposite knee)
- The patellofemoral compartment (front of the knee)
Typically, arthritis or degenerative process starts in one compartment and eventually progresses to the rest of the knee.
If the degeneration is limited to only one compartment, partial knee replacement is recommended. It is beneficial as the implant is much smaller and only the unhealthy bone and soft tissue are reconstructed during surgery.
One of the main benefits of partial knee replacement surgery is that in this procedure, normal structures such as the cruciate ligaments and uninvolved compartments can be left alone. And as the dissection is minimal, normal neural pathways which are interrupted during total knee replacement procedures are also spared in this alternative treatment.
Partial knee replacement surgery comes with lower risk of developing complications after surgery, decreased hospital and recovery time, increased range of overall motion and greater patient satisfaction.
When it comes to life expectancy of the prosthetic joint, studies show that over 90% of partial knee replacements function well for more than 10 years after the surgery. Patients with both partial and total knee replacement joints seem to prefer the former as compared to the latter, suggesting that they feel the partial knee replacement to feel more “normal”.
The choice of partial or total knee replacement surgery is done after careful diagnosis and study of the damaged joint. There is a higher failure rate for partial knee replacement surgery as compared to total knee replacements. As not all patients are ideal for partial knee replacement surgery, correctly judging the suitability of the procedure is critical to the outcome.
With significant improvements in prosthetic design as well as surgical techniques, both procedures can be performed with increased precision to realign the knee and correct any issues. For patients opting for either procedure, care should be taken while choosing the prosthetic. The surgeon generally recommends the prosthetic he or she is most comfortable using, hence discuss the available options at length with your doctor.
Ques: How to avoid knee replacement surgery?
Knee replacement surgery is an elective procedure, especially if it is being performed to manage conditions such as osteoarthritis. This surgery is generally done if all other non invasive treatment options are proving ineffective. Weight loss, muscle strengthening exercises and stretches to improve flexibility are generally the preliminary steps taken to strengthen the knee joint. Medication is also given to the patient to manage their pain.
Ques: How long does a knee replacement surgery last?
Total knee replacement surgery lasts for about two hours and requires 3-5 days of hospital stay. Partial knee replacement surgeries last around 45 minutes and require 1-2 days of hospital stay. Not all patients are ideal candidates for partial knee replacement surgeries. In some cases, doctors will decide on which procedure to perform after they make the incision and view the damage to the joint.
Ques: What are the risks of knee replacement surgery?
Like all other surgeries, there are several risks associated with total knee replacement surgery. These include
- Infection in the surgical wounds
- Developing blood clots in the leg vein or lungs
- Heart attack
- Nerve damage
Seek immediate medical assistance if you notice:
- Fever (temperature greater than 100 F)
- Drainage from the surgical site
- Increasing redness, tenderness, swelling and/or pain in the knee
Also, read: The risk of delaying Knee Replacement Surgery