What Is Minimally Invasive Knee Replacement Surgery?

Minimally invasive knee replacement surgery is a term used to describe several procedures and modifications of conventional knee replacement aimed to reduce tissue trauma. Unlike other procedures that involve a deep cut on your knee to expose the joint, the procedure's main goal is to reduce or prevent postoperative pain, discomfort, and the need for physical therapy.

In this procedure, the surgeon uses shorter or small incisions and a totally different technique to expose your knee joint. Unlike the traditional knee replacement techniques, a minimally invasive technique may not be for all patients. Your doctor will always discuss with you the different procedures available for your knee treatment.

Procedure description

In any knee replacement surgery, the damaged bone and cartilage from the knee surface is cut off along with the soft tissues. The aim of a knee replacement surgery is to give the patient a pain-free knee that will allow him or her to do normal activities. A minimally invasive procedure is different from other traditional procedures since it uses a shorter incision. To understand their difference, here is an explanation of the two procedures:

Traditional Knee Replacement

In this procedure, your surgeon will make an 8 to 10-inch vertical incision on your knee front to access the joint. After the incision, the surgeon will:

• Prepare the bone - the damaged bone from the tibia and femur are cut and removed. The damaged cartilage is removed as well.
• Positioning the implant - the removed bone and cartilage are replaced with plastic or metal parts.
• Resurfacing the patella - the undersurface of the patella or the kneecap is removed and then replaced with a plastic button.
• Inserting a spacer - the last step that involves the insertion of a plastic spacer between the two metallic components to form a smooth gliding surface.

Minimally Invasive Knee Replacement

A minimally invasive knee replacement is very similar to the traditional one except for the length of tissue cutting required. The artificial prosthesis used in other procedures are also the same. However, the surgical instruments used in this procedure to cut the femur and tibia are different from those used in the traditional knee replacement.

This surgical procedure is achieved by making a shorter incision of about six inches compared to the eight to ten-inch incision in a traditional knee surgery. A small incision is aimed to allow fewer disturbances to the knee tissues.

In addition to the small incision, the whole procedure used to open the knee is less invasive. The techniques used in the surgery are "quadriceps sparing", which means that they avoid trauma formation to the knee front muscles and on the quadriceps tendon. Other less invasive procedures such as subvastus and midvastus approaches are less invasive compared with the traditional knee replacement and are used to make incisions in the thigh muscle. Since the techniques used to open the knee to expose the joint involve less disruption to the muscle, it can lead to a reduced preoperative pain and less recovery time.

The period of hospital stay after a minimally invasive knee replacement surgery is almost the same as that of a traditional surgery ranging from one to four days. Physical therapy and rehabilitation are very important for a quick recovery. Your physiotherapist and surgeon will educate you on the exercises that you will do to help restore strength and improve one's movement.

Who should undergo a minimally invasive knee replacement?

As mentioned earlier, this procedure is not suitable for every patient. Your doctor will first conduct a medical evaluation to consider some factors before deciding on the best procedure that you should undergo. Generally, patients who are qualified for a minimal incision include thinner, younger, and healthier individuals, who are determined to participate in a rehabilitation process. This procedure is not suitable for overweight individuals who had other knee surgeries before. Moreover, it may not be suitable for people with severe knee deformities and those who have other health conditions that can slow down the healing process. Such patients are at higher risk of developing complications. 

Are there risks for minimally invasive surgery?

Just like other types of surgeries, this surgical procedure is also associated with complications such as:

• nerve injury
• excessive blood loss
• formation of blood clots
• fracture formation during the operation
• infection after the surgery
• improper fixing of the implants

In addition to the complications, minimally invasive surgical procedures will always take a longer time to complete. Therefore, a patient who had another type of surgery in the past should be prepared to follow some precautions and should also adjust to a new lifestyle with prostheses. Some other uncommon expectations such as lack of preparation and failure to become active during the procedure can lead to poor outcomes and disappointment after the surgery. Different people will have a different reaction to the procedure depending on their body size and other medical conditions. Family support, mental health, and cultural background are other factors that may affect a minimally invasive knee replacement surgery.

Results for Minimally Invasive Knee Replacement Surgery

Minimally invasive knee replacement surgery is a new technique introduced to treat arthritis on a knee joint. Surgeons are gaining more experience as the technique is advancing in the market. If the knee implants are fixed properly, the new knee can last for decades.

This procedure will give you an early discharge from the hospital with lesser pain. Moreover, you can return to your normal activities a few weeks after the surgery. Less exercise and physiotherapy are also needed after discharge from the hospital. However, there are some specific complications that are associated with the new surgical method. Your surgeon's experience matters a lot to achieve successful results. Patient education and surgeon experience are the keys to getting desirable results.

Bottom Line

It is very important to be educated about the whole surgical procedure before undergoing it. Patients should also be given realistic goals for their recovery. You should keep in mind that different patients recover differently.

The term "minimally invasive knee replacement" is somewhat misleading to many. Some may associate it with altered emotions, discomfort, and a long recovery period. It is not a risk-free surgery, but it will decrease deep muscle trauma that is associated with the surgery.