Essential Keys To A Pre-Op Biomechanical Evaluation

Robert D. Phillips, DPM

Emphasizing the importance of proper biomechanical assessment as a foundation for successful surgical outcomes, this author discusses key measurements such as the resting calcaneal stance position and offers pertinent evaluation pearls that can make an impact in flatfoot and hallux valgus surgery.

I have spoken many times on the importance of separating the term “biomechanics” from the term “orthotic therapy.” The reason that this thought pattern continues to exist in our profession is that in the traditional departmentalized school of podiatric medicine, surgery and biomechanics were two separate departments. The people who were devoted in trying to measure ranges of motion of joints went in the biomechanics, non-surgical department.

   I hope that we will soon read about this archaic form of thinking the same way that we now read about “bloodletting” practices in historical medical books.

   Biomechanics is a science. It is not a therapy. Biomechanics should be the basis on which we understand why tissue is experiencing stress and why deformities occur. In associating with those I consider to be great clinical biomechanists, I have been impressed with their surgical skills. It makes sense to argue that the more we know about the pathomechanics of any deformity, the more likely we are to do the right surgery to correct and try to prevent that deformity from recurring.

   It is indeed disappointing to attend conferences where many are lecturing about doing surgery without giving any specifics of the indications for that surgery. I also continue to marvel at the number of surgeons who adopt a particular surgery to perform because the literature says that a majority of patients who have the surgery have a good or excellent result. One almost never sees in the literature any inquiry as to which patients have the best results and which have only fair or poor results.

   It is true that there are many factors that play into this categorization of results. These issues include general health issues, adherence issues, operative technique issues, etc. However, researchers seldom report and correlate in-depth preoperative static and dynamic tests with the outcome of the procedure.

   When one thinks about the ramifications of doing surgery, the surgeon must do everything possible to get the best results. Unlike a prosthetic or orthotic device that one can discard after a mistake, surgery cannot be discarded if an error in judgment leads to a less than desirable result. I predict that standards of care in the future will gradually shift and more biomechanical analysis will be expected as part of the preoperative evaluation for many musculoskeletal surgeries.

Biomechanical Considerations For Flatfoot And Abnormal Pronation

A full discussion of preoperative biomechanical indications for surgery is prohibitive in such a brief article as this so I will briefly address a couple of basic surgical categories.

   The first one, flatfoot surgery, may seem to be the most obvious. While we continue to see that “pes planus” is still a code-able ICD-9 diagnosis, podiatric medicine has tried to change the idea that flat feet are a problem. Indeed, there are many flat-footed people who will function well for an entire lifetime and never need any treatment.1

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