Knee Replacements are Becoming “Personalized”

By John T. Pinnello, M.D.

This past year marked the introduction of a new technology used in performing knee joint replacement surgery. Although the components that are used to replace the arthritic joint are basically the same as in recent years, the technique is changing, due to the use of computer assisted technology.

Over the past decade minimally-invasive techniques have been popularized in all aspects of medicine, and knee joint replacement surgery is no exception. This has resulted in smaller incisions, shorter hospital stays, and better pain control for those going through total knee replacement. Simultaneously, the use of computers to assist surgeons and to improve accuracy has also been advancing rapidly. The original concept of computerized surgery was to use the computer during the surgical procedure itself. It would provide immediate feedback and help guide the surgeon to remove the exact portion of the arthritic joint. Although still being developed, this concept currently is expensive, time-consuming, and usually requires enough room (and a larger incision) to fit the computer’s needs.

The introduction of personalized knee replacements combines both (minimally invasive, computer assisted) of these concepts. The idea is to use the computer’s precision and accuracy outside the operating room prior to the actual surgery itself. A few weeks prior to the actual joint replacement procedure, the patient has a MRI (magnetic resonance imaging) scan performed of the knee. A computerized three-dimensional model of the patient’s knee is created along with matching computer-generated positioning guides. These are the same type of guides that the surgeon usually uses to remove the arthritic joint during the surgical procedure, but in this case, they are specifically manufactured for the patient. The advantages of this technique are multiple. In the past, preoperative surgical planning has been based on standard two-dimensional X-rays. With the MRI, the 3D model, and the personalized positioning guides, surgeons have access to a greater level of detail and precision for implant position and assisted alignment before the surgery. This allows for personalized implant positioning and may help enhance surgical efficiency.

Traditionally, in order to accurately place the femoral (thigh bone) positional guide, the surgeon would use a long rod that is placed up and into the thigh bone. Similarly, some surgeons also rely on this technique for the tibia (shin) bone as well. With the personalized positioning guides, the surgeon places the guide on top of the bone. This is less invasive and could cause less trauma to the bone and the surrounding areas of the leg. By having accurate measurements prior to surgery and using fewer instruments to position the guides, the surgeon may be more efficient and decrease the patient’s time in surgery, which could lead to better outcomes. To summarize, there are significant gains that may be achieved by the use of this new technology. More precise preoperative planning and more accurate intraoperative implant positioning of the joint components are potential benefits to the surgeon. The patient may benefit from less bone and soft tissue trauma, and may spend less time in the operating room. All of these factors may lead to better outcomes. Castle Orthopaedics and Sports Medicine, S.C. is now pleased to offer this new advancement in knee replacement surgery. Patients need to meet specific clinical criteria to be considered for this procedure. Please call for more information or to schedule a consultation.

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