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from the American Academy of Orthopaedic Surgeons

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Minimally Invasive Total Knee Replacement

Total knee replacement (also called knee arthroplasty) is a common orthopaedic procedure that is used to replace the damaged or worn surfaces of the knee. Replacing these surfaces with an implant, or prosthesis, will relieve pain and increase mobility, allowing you to return to your normal, everyday activities.

  • The traditional approach to knee replacement uses a long vertical incision in the center of the knee to view and access the joint.
  • Minimally invasive total knee replacement is a variation of this approach. The surgeon uses a shorter incision and a different, less-invasive technique (requiring less cutting of tendons and ligaments) to expose the joint — with the goal of reducing post-operative pain and speeding recovery.

Unlike a traditional total knee replacement, the minimally invasive technique is not suitable for all patients. Your orthopaedic surgeon will discuss the different surgical options with you.


During any knee replacement, the damaged cartilage and bone from the surface of the knee is removed, along with some soft tissue. The goal of knee replacement is to provide the patient with a pain-free knee that allows for the return to daily activities.

Traditional Knee Replacement

To perform a traditional knee replacement, the surgeon makes an 8- to 10-inch vertical incision over the front of the knee to expose the joint. The surgeon will then:

  • Prepare the bone. The damaged cartilage surfaces at the ends of the femur and tibia are removed, along with a small amount of underlying bone.
  • Position the metal implants. The removed cartilage and bone are replaced with metal components that re-create the surface of the joint.
  • Resurface the patella. The undersurface of the patella (kneecap) is cut and resurfaced with a plastic button. Some surgeons do not resurface the patella. The decision about whether to do so depends on:
    • How much arthritis is present under the patella.
    • The thickness of the patella. If the patella is too thin, there is a risk of fracture if it is resurfaced.
  • Insert a spacer. A plastic spacer is inserted between the metal components to create a smooth gliding surface.
total knee replacement implants

In a total knee replacement, the arthritic portion of the joint is replaced with metal components. A plastic spacer is placed between the components.

Minimally Invasive Knee Replacement

In minimally invasive total knee replacement:

  • The surgical procedure is similar to a traditional total knee replacement, but there is less cutting of the tissue surrounding the knee.
  • The artificial implants used are the same as those used for traditional total knee replacement. However, specially designed surgical instruments are used to prepare the femur and tibia and to place the implants properly.
  • The procedure is performed through a shorter incision — typically 4 to 6 inches versus 8 to 10 inches for a traditional total knee replacement. A smaller incision allows for less tissue disturbance.
  • In addition to a shorter incision, the technique used to open the knee is less invasive. In general, techniques used in a minimally invasive total knee replacement are "quadriceps sparing," meaning they avoid trauma to the quadriceps tendon and muscles in the front of the thigh. Other minimally invasive techniques called "midvastus" and "subvastus" make small incisions in the muscle but are also less invasive than a traditional total knee replacement. Because the techniques used to expose the joint involve less disruption to the muscle, the patient may have less post-operative pain and a reduced recovery time than with a traditional total knee replacement.
  • The hospital stay is similar to the length of stay after a traditional total knee replacement. Some patients have outpatient (same-day) surgery, while others stay in the hospital for 1 to 4 days.
  • Physical therapy is a critical component of recovery, as it is for a traditional total knee replacement. Your surgeon or a physical therapist will provide you with specific exercises to help increase your range of motion and restore your strength.

Candidates for Minimally Invasive Total Knee Replacement

Minimally invasive total knee replacement is not suitable for all patients. Your doctor will conduct a thorough evaluation and consider several factors before determining if the procedure is an option for you.

Compared with patints who undergo traditional surgical procedures, candidates for minimally invasive proceduress are generally:

  • Thinner
  • Younger
  • Healthier
  • More motivated to participate in the rehabilitation process

Minimally invasive surgeries may be less suitable for patients who:

  • Are overweight
  • Have already undergone other knee surgeries

In addition, a minimally invasive total knee replacement specifically may pose a higher risk for patients who:

  • Have a significant deformity of the knee
  • Are very muscular
  • Have health problems that may slow wound healing


Minimally invasive knee replacement is an evolving area, and more research is needed on the long-term function and durability.

  • The short-term benefit of minimally invasive total knee replacement is reported to be less damage to soft tissue, leading to a quicker, less painful recovery and more rapid return to normal activities.
  • Current evidence suggests that the long-term benefits of minimally invasive total knee replacement do not differ from those of traditional total knee replacement.

Like all surgery, minimally invasive surgery has a risk of complications. Possible complications include:

  • Infection
  • Wound healing problems
  • Blood clots
  • Nerve and artery injuries
  • Errors in positioning the prosthetic knee implants

Like a traditional knee replacement, minimally invasive knee replacement should be performed by a well-trained, highly experienced orthopaedic surgeon. Your orthopaedic surgeon can talk to you about their experience with minimally invasive knee replacement, and the possible risks and benefits of the techniques for your individual treatment.

Last Reviewed

March 2024

Contributed and/or Updated by

Neil P. Sheth, MD, FAAOSJared R.H. Foran, MD, FAAOS

Peer-Reviewed by

Mary K. Mulcahey, MD, FAAOSStuart J. Fischer, MD, FAAOS

AAOS does not endorse any treatments, procedures, products, or physicians referenced herein. This information is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific orthopaedic advice or assistance should consult his or her orthopaedic surgeon, or locate one in your area through the AAOS Find an Orthopaedist program on this website.