(Updated February 2005)

We dislike qualified yes answers. In this case, however, a qualified answer is justified. Nearly three years ago, we ran an article on this new “hot topic” in our newsletter (Spring 2002, Issue #1) titled: “Minimally Invasive Surgery: Hip or Hype”. In that article we differentiated between what we felt was “minimally invasive” and “minimal incision” surgery. In other words, we felt that a minimal incision did not always mean that the surgery was less invasive, since under the skin, the same degree of surgical dissection may or may not be utilized. We stressed that these were developing techniques, and that there were potential risks primarily due to the lack of visualization. More cases and longer follow-up were felt to be required. We said we would cautiously begin using these techniques if we felt they were safe.

In the last three years this concept has exploded!  Both direct to consumer and surgeon practice marketing have created a tidal wave of patient demand for these “new procedures”. Who wouldn’t want to have their surgery with the least invasive technique and with the fastest, least painful recovery? BUT, here comes the “but”: this assumes that these techniques will result in the same high success rates that have been proven with the traditional surgical technique. No one wants to trade a higher risk of early failure or lesser quality long-term success for a few weeks of faster recovery. To date there are few published results by the pioneers of these new techniques. What has been published has not confirmed the benefit of “minimal incision” or “minimally invasive” surgery.  This area has not yet been studied well and has not received the necessary “peer review” by the orthopaedic surgeon community. At this time, the onus is on the individual surgeon to insure that he or she can do the same high quality job through either a smaller, or less invasive approach.

We now feel that we can do most of the procedures safely using a less invasive approach utilizing a minimal incision. Most of our first-time hip replacements are now done through a much smaller incision. The actual length of the incision depends on the size and obesity of the patient. In thin patients we have gone from the traditional 8-inch incision to a 4-inch one. In heavier patients we may need to make a 6-inch incision.  We, and others call it the “Posterior Mini”. We also have decreased some of the muscle dissection, so this qualifies as being less invasive. For us the “mini” is now standard. We simply adjust the length of the incision to the size of the patient. If, however, there are special circumstances, such as retained hardware from a prior surgery or an anatomic deformity, we will use the standard approach.

We tried using the so-called “Two-Incision” technique, but found it to be unsafe. In fact, many surgeons have tried the “two-incision” technique and abandoned this. Reports at national meetings indicate that the complication rate is higher for this technique, particularly the rate of femoral fracture. 

We are also now doing minimally invasive knee surgery for the uni-compartmental knee replacements. This is where only the affected medial or lateral compartment of the knee is replaced. Again the size of the incision depends upon the size and obesity of the patient. In patients with thin knees, the incision is about 3-inches, as compared to the traditional 6-inches. This again qualifies as being minimally invasive, since we have eliminated the splitting of the quadriceps muscle. Although the indications for uni-compartmental replacement are increasing, they still represent less that 10% of knee replacements done in our practice.

Total knee replacement is beginning to be done through a less invasive approach. It requires a larger incision than the uni-compartmental replacement, simply because the implants are larger and the bone preparation is more extensive. The principle is still the same, however: limit the dissection into the quadriceps muscle. It seems that the less dissection into the quadriceps muscle, the more rapid the recovery. There are various techniques for this, and we are exploring them to see which we think is best for our patients.

We are monitoring and studying the short-term as well as long term performance of our patients in whom we use minimally invasive techniques. So far, our patients seem to report less pain and may be going home a day or two earlier. At their 6-week follow-up check they seem to be functioning at a higher level. By 3 months, there is less of a difference and by 6 months, there seems to be minimal differences. Our post-op. x-rays still show the same high quality job and we have not had any complications that we can attribute to the change in technique.

New instruments to help with minimally invasive techniques are being developed every day. New implants, that are designed to be implanted with these techniques, are on the horizon. Computer navigation techniques are coming that may improve our ability to “see” using virtual reality. Robotics (i.e. ROBODOC) will be adapted to insure the execution of the surgical plan without the need for direct visualization.

The future continues to look promising for minimally invasive techniques in hip and knee surgery, BUT we must do it safely.  You have our assurance that there will be no loss of quality or long-term success.