David R. Lionberger, MD

Patient Education: MIS Total Hip Replacement

What Size Incision Fits Your Hip Replacement?

Minimally invasive surgery, better known as MIS hip replacement, has been recently developed as an offshoot of the orthopedic joint replacement that is designed to lessen the rehabilitation time, and in many instances accelerate performance of joint function and capability. It goes beyond merely making a tiny scar to look good at the beach. It also minimizes trauma to the soft tissue surrounding the joint in question. Currently, development that is being heralded as a success in follow-up studies includes total hip replacement as well as total knee replacement.

Total hip replacement can be done in a variety of ways. This is nothing new to the orthopedic community, for over the last three decades since total hip replacements have become commonplace, there have been at least three predominant exposures utilized. One is a lateral exposure, the second is an anterior exposure, and the third is a posterior exposure. When one looks at the incision techniques developed by development surgeons, these are not new approaches at all. They are merely a shrinkage of the same exposure utilized for decades. What is new is the ability to shorten the incision and provide access to the regions in question so as to insert the prosthesis without direct visualization.

The question of direct visualization, or exposure to the work that you are doing in a hip replacement, obviously presents an obstacle of accuracy and position awareness. Because of this, a number of surgeons, including myself, have been working diligently on guidance systems that will provide a framework of giving the surgeon better measurement of the position and orientation of the prosthesis. As our incisions become less open and more restrictive, we need additional means of tracking the prosthesis to correctly place them for the maximum performance. This can be done by means computer-assisted orientation surgery (CAOS), MIS, or a combination of the above.

Approximately one half of all dislocations are attributable to positions of the acetabular component. Wear of the surface is also affected by positioning of the acetabular cup. These two issues make investigation of acetabular placement one of the most important applications for computer-assisted total hip replacement surgery.

The disadvantages of the minimally invasive surgery include the obvious discussions above of inaccurate placement of the prosthesis. It also takes longer to do this procedure. For this reason, many surgeons have not felt compelled to adopt this technology. What's more, the exposure provides less flexibility in entry portals for the prosthetic insertion, and therefore fractures are much more likely to occur as well as soft tissue trauma. Because there is less ability to monitor soft tissue tensions, the likelihood of fractures, nerve injuries, and vascular injuries are slightly increased statistically. Finally, this surgery isn't for everyone. As with any technology which requires more input on the part of staff and surgeons, the patient has to be of the appropriate body mass and size, and they have to be motivated to utilize the technology that's been provided for them. Merely having a small incision for bragging rights is not worth the above-mentioned risks if one is not going to take advantage of the technology provided.

The upside of minimally invasive surgery of the hip is a hope of improving the likelihood of instabilities and dislocations as well as less downtime for rehab. If all the criteria of presurgical planning is met by the patients and the surgery is successful, there can be no debate that the minimally based surgery of the hip is here to stay and will only serve to become better and more available in the years to come. It will probably never be the standard of care in the patient who carries more weight. Yet that provides motivation and stimulus to all of us to keep ourselves healthy and agile in our advancing years. Meanwhile, my colleagues and I will continue to endeavor to improve and perfect the technology that extends this to a wider array of patient population. It has been and continues to be an exciting time in orthopedic surgery as these opportunities become available to patients and provide so much of an improvement in surgical recovery refinements. Please feel free to visit the rest of our web page to find out more about other minimally invasive surgical technologies.

David R. Lionberger, MD

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