Minimally Invasive Total Knee Replacement

Knee replacement is a surgical procedure that decreases pain and improves the quality of life in many patients with severe knee arthritis. Typically, patients undergo this surgery after non-operative treatments (such as activity modification, anti-inflammatory medications, or knee joint injections) have failed to provide relief of arthritic symptoms. Surgeons have performed knee replacements for over three decades, generally with excellent results; most reports have ten-year success rates in excess of 90 percent.

Broadly speaking, there are two types ways to insert a total knee replacement: the traditional approach, and the newer minimally-invasive (sometimes called quadriceps-sparing) approach.

Traditional total knee replacement involves a roughly 8” incision over the knee, a hospital stay of 3-5 days, and sometimes an additional stay in an inpatient rehabilitation setting before going home. The recovery period (during which the patient walks with a walker or cane) typically lasting from one to three months. The large majority of patients report substantial or complete relief of their arthritic symptoms once they have recovered from a total knee replacement.

Minimally-invasive quadriceps-sparing total knee replacement is a new surgical technique that allows surgeons to insert the same time-tested, reliable knee replacement implants through a shorter incision using surgical approach that avoids trauma to the quadriceps muscle which is the most important muscle group around the knee. This new technique, which is sometimes called quadriceps-sparing knee replacement uses an incision that is typically only 3-4” in length and the recovery time is much quicker – often permitting patients to walk with a cane within a couple of weeks of surgery or even earlier. The less-traumatic nature of the surgical approach also may decrease post-operative pain and diminish the need for rehab and therapy compared to more traditional approaches.

The main potential benefits of this new technique include:
More rapid return of knee function. Patients who undergo this procedure seem to get muscle strength and control back more quickly than patients who have had traditional total knee replacement. This is because the quadriceps muscle and tendon are not divided in the course of the surgical exposure like in traditional knee replacement, and the kneecap is not everted (flipped out of the way) as it is in traditional total knee replacement.

While this procedure would not be worth performing for cosmetic benefits, many patients do prefer the shorter incision. Traditional knee replacement incisions often measure 8” or longer; minimally-invasive quadriceps-sparing knee replacement incisions are about 4” in length for most patients. Decreased post-operative pain. This may be a function of the smaller incision and the fact that the incision stays out of the important quadriceps muscle/tendon group. Same reliable surgical implants as traditional knee replacement. Much has been learned about implant design in the nearly 40-year history of contemporary knee replacement. Minimally-invasive quadriceps-sparing total knee replacement is an evolution of surgical technique, which permits the use of time-tested implant designs. This gives some reassurance that while the surgical approach is new, the implants themselves have a good proven track record.

The major apparent risks of the procedure compared to traditional total knee replacement are similar. Though surgeons have studied the approach, the studies are recent and have replicated (repeated and verified) by only a few groups of surgeon-scientists. These studies give some insight into which patients and patterns of arthritis are most suitable for this procedure. The relative novelty of the approach, it is likely that as time passes we will discover more about the risks and shortcomings of this technique. Also, even an experienced knee replacement surgeon will have performed many more surgeries through the traditional approach than through the less-invasive method; we know that the more procedures one does, the more reliable the results are.

The procedure is more challenging. Operating through a smaller surgical window takes some getting used to, and this can increase operative time compared to procedures performed using the traditional technique. This may increase the likelihood that an intra-operative injury to tendon or ligament might occur, which could compromise the result. This may also increase the likelihood of component malalignments, which could affect function and durability. However, two preliminary studies on this technique in fact found that these adverse outcomes did not take place.

Total Knee Implants

In addition to the our quadriceps sparing approach to total knee replacement, we also take an individualized approach for selecting which knee implant is best suited for our patient needs and anatomy. Our current total knee replacement system includes the following.

Smith and Nephew Legion is from the Genesis 2 family of proven performance implants. By virtue of the unique implant design features and materials the Legion Total Knee System is ideally suited to address the common patient factors including age, motion, anatomy, gender, pathology and metal sensitivity. The Legion Narrows are specifically designed for the female anatomy. This knee is available in an Oxinium (ceramic) femoral component. Recently introduced is the so called “30 Year Knee” with Verilast Technology.

Zimmer Gender High Flex knee is designed specifically for a woman’s knee. Zimmer has incorporated 3 specific design characteristics to closely match the shape and proportion of a woman’s knee. These design features include smaller shape and modified proportions, a more angled knee cap groove, and a narrower and thinner anterior femoral flange.

Zimmer Nexgen High Flex knee incorporates advanced design to improve knee function, such as climbing stairs with minimal difficulty or pain and high-flexion activities like golf, working in your garden, and those activities that require bending deeply at the knee can be addressed.