Quad-Sparing Knee Replacement Surgery: The New Gold Standard

All aspects of surgery are being affected by a new minimally invasive trend. No matter what procedure is being performed, if there is a way to do it with less negative impact on the body, today’s surgeons are working on ways to make it happen. A few weeks ago I wrote a post about the mini hip replacement that has developed recently. This week I will write a similar post about a relatively new procedure known as a quadriceps-sparing total knee replacement. It has the same end result as a traditional total knee replacement, or TKR, but it does so with considerably less damage to the surrounding tissue in the operating room. I believe that this new procedure, unlike the total hip replacement, is a great improvement on the traditional surgery. While it is a more difficult operation when compared to the traditional TKR, its advantages are more than just cosmetic and I believe it is a superior choice for all people looking for a knee replacement.

During a traditional knee replacement surgery, a vertical incision is made along the top of the knee that exposes the quadriceps muscle. A secondary incision is then made through the quadriceps to expose the knee joint. At this stage, many tendons and much muscle tissue has been cut, resulting in unavoidable blood loss and a need for major anesthesia. The knee prosthesis is then inserted by a method similar to the total hip replacement. A plastic cup is placed on one end of the joint and a metal ball is attached to the other, as can be seen in the x-ray at left. The new joint is then assembled and aligned and tested for mobility. Once the surgeon is satisfied with the functionality of the prosthesis the soft tissue is sutured and the incisions are closed. Traditional knee replacement patients will typically stay in the hospital for three to four days, and then have up to eight weeks of physical therapy to recover completely.

This is the area in which the quad-sparing procedure becomes most attractive. Patients who undergo this surgery can expect to leave the hospital in less than one day, and the reasons are multi-fold. First of all, the incision is much smaller. In the traditional surgery, the incision is approximately eight to twelve inches in length. With the new technique it can be as small as three inches, with most being about four (see image below right). The incision is made on the side of the knee, which allows the joint to be exposed without severing any tendons or disturbing much muscle tissue. Because of this, there is less blood loss compared to the traditional TKR and less anesthesia is needed. Less anesthesia is almost always preferred by surgeons since surgery itself is a very traumatic experience for the body and heavy sedation only complicates the recovery process.

After the surgery is complete, the patient can usually be walking around as soon as he/she wakes up. Since there is no major structural trauma caused by the surgery, the road to recovery is a very quick one. The success rate is astounding. Take this study done by Rush University Medical Center, for example. In their trial run of fifty patients, ninety-six percent were able to go home the same day as their surgery. Granted, each patient was the first one treated that day (allowing maximum same-day recovery time), but it is still quite impressive. Additionally, all patients were required to pass an inspection before discharge. A patient was deemed fit to go home if he/she could get out of bed unassisted, stand up from a sitting position, walk 100 feet, and ascend and descend a full flight of stairs. When one considers the fact that these patients were able to perform these basic actions on the very day that they had a total knee replacement surgery, it is really quite remarkable.

As for the long-term reliability of this procedure, only time will tell. It has still been less than five years since the first one was performed, so longevity has not yet come into play. There is the obvious concern that the prosthesis may not be properly aligned in the quad-sparing method due to a lack of direct visual confirmation during surgery. However, unlike in the mini hip replacement, I feel that there are enough alignment tools available to the surgeon to confirm a good placement without the need for a direct line of sight. While the alignment process may take longer with the quad-sparing method due to a need for x-rays in the operating room, the whole procedure takes the same time. Both techniques take about two hours to complete, although prep time may be longer for the quad-sparing method.

As I said earlier, I think that the quad-sparing method is going to become the new standard for knee replacement. Since the quadriceps is the dominant muscle responsible for stabilizing the knee, it makes perfect sense that it should be preserved rather than aggravated during surgery. As surgical imaging advances in the future, it will only become easier for this surgery to be performed with the same kind of accuracy associated with the traditional method. I look at this as great news for the millions of Americans who are aging and becoming candidates for knee replacement surgery. Knowing that the recovery will be so quick will surely make it a less stressful experience.