The human foot is both magnificent and mysterious. A complex structure of 28 bones bound together by ligament and connective tissue in a series of arches to make a half dome (according to Gray's Anatomy) and acted upon by muscle/ tendon units to allow purposeful stance,balance, and locomotion. My intrigue with this wonderful, yet humbling, section of anatomy began in 1983, when as a Certified Athletic Trainer (NATA) I decided that changing the pitch of an athlete’s foot/ankle complex within the shoe might be useful in the treatment of all sorts of running/cutting related injuries and syndromes. I was intrigued, a little naive', and hopeful. The results were interesting and exhilarating! Many of the athletes at the Alumni Gymnasium training room of Bates College responded quite positively to crude, simple direct mold inserts made of thermo foams that changed shin pain, patella-femoral syndromes, and more. The athletes were off and running and I was on the highway (a long Route 66) of exploration, wonder, and education. The truth is that the highway never ends. After 32 years and the making of 13,000 pairs of custom foot orthotics (FOs) I still learn, tweak orthoses, and redo when the outcome isn’t quite what was planned or expected. Yet, the challenge, beauty, and thrill of biomechanical controls in the treatment of lower extremity injuries remains. My dad, in his quaint Vermont humor, used to say, “You know, Rod, the more you know, the stupider you get,” Isn’t it true? Sometimes a point learned leads to more questions. I suspect that this is true for all caregivers. For me, it clearly demonstrated the majesty and uniqueness of every foot, every patient, every human condition the enters our door.
“This is where it’s at”, cited Jim Russ, former director and educator of Northwestern University’s Orthotic & Prosthetic program as we toured a small, independant practice just north of Chicago on a brisk November day in 1990. The practice was loaded with impressions and plaster casts of feet and limbs destined for the vacuum stage of laminated layers of thermocork, plastizote foam or copolymer, whatever the case may be. I wondered how a cast is modified to make a comfortable and effective foot orthotic. Where does one push safely to change foot position and harness ground reaction forces? Was there a difference between the the shell materials and the forces they project? The questions went on and on. Yes, we were instructed about slipper casting and cursory biomechanics but the world of custom foot orthoses was a deep sea, abounding in white caps of theory and breakers of technical methodology. Every breaker was different and each white cap held a different piece of orthotic information. But, if one has to surf the sea it helps to examine the breakers. The study of each wave, the nuance of each salty curl helps the orthotist decide what works and what does not. Then, of course, there has to be practice - the art and science of riding the wave. Careful study of Gray’s Anatomy, medical readings, consults with colleagues, and the employment of an orthotic design that meets one’s understanding of biomechanics and treatment philosophy are surfing requirements in the world of orthotics. Since I developed in the waters of sports medicine, much of my philosophy and theory is connected to the high breaker - the athlete. However, the orthotist has to treat the the low breaker and the swell; the non athletic adult with foot pain or the diabetic with complex, systemic issues that require different approaches -requiring a different surfboard altogether. In a way, the “surf was always up”.
Over the years, principles of foot support overlap, blend if you will. For example, the tenet of providing every diabetic foot, neuropathic or not with an accommodative design and corresponding soft shell orthosis is safe and effective, but does the orthosis provide for function?
Yes, the essence of treatment is to protect the neuropathic foot, offload when required, and team up the orthoses with a deep, rockered, well fitting shoe for ambulation. But what about function? Does not the diabetic foot require triplanar control when over- pronation or supination is present. Sometimes, as I have viewed the larger picture, the requirements for movement and activity leap out. How many times have we heard the diabetic female (62 inches and 180 pounds) or male (70 inches and 300 pounds) state,“I weigh too much and need to exercise.” Over time, the desire to have the orthosis” treat the whole person” has forces me to integrate biomechanical principle with accommodative features in FOs. If joints are mobile, skin intact, sensate able, patient mature and willing, there is a way to treat a pronated diabetic safely and improve lower extremity efficiency without risk. This treatment provides the patient with an orthosis that provides for activity - a treatment that encourages and promotes function.
Over time I have concluded that accommodation is nice, but biomechanical features with accommodation is better. The biomechanical normalizes foot position, equalizes forces “en trio”, changes how the center of gravity moves through the foot, and improves gait efficiency. Many a marathoner or avid runner has marveled at follow up following a biomechanical FO fitting with the retort, “I just had three personal bests in a row”. Shouldn’t we provide all individuals with a foot/ankle complex that is designed for activity? Weight loss, fitness, activity, sense of accomplishment, well being, stress release,cardiovascular improvement are by products of exercise. Maybe we should treat the low rollers like high breakers if possib
On Wolffe’s Law
The useful description of WOLFFE’s LAW is the summary tenet: “form follows function”. That is, according to Julius Wolfe, a German surgeon in the 19th Century, the modeling and remodeling of bone in a healthy individual are the direct responses of forces/loads placed on it. This law is well known and utilized in orthopedics,physical therapy, and other medical disciplines when it comes to healing bone. Over time damaged bone will remodel to gravitational, centrifugal, musculo-tendinous forces placed upon it. A bent or broken bone can heal or straighten if the mechanisms within bone are intact and healthy.
How does this relate to the ankle/foot complex? Is not the architecture of the foot bone bound by living tissue? The two bony arches of the foot, the medial and lateral columns, are composed of bone uniquely arranged in columns designed to support, adapt, and propagate motion through changes in articular relationships. Gray’s Anatomy had it right when it it described the foot/ankle as a “Living foot” (Gray’s Anatomy, 35th British Ed.,WB Saunders,Philadelphia, 1973, 468-471.). Connective tissue, muscle, and ligament do not share the unique ability of bone to remodel with appropriate forces applied, but they can be reorganized by means of ground reaction forces into positions of function that make for improved and efficient locomotion. I fully subscribe to to reverse of Wolffe’s law when it comes to the human foot, that is: function follows form. Remodeling or normalizing by means of orthotic intervention produces efficiency and purposeful motion that enhances pain free and improved activity. Activity promotes health and well being. The injured athlete gets better, runs faster, trains harder and so does the inactive adult or diabetic who is looking for a better way of life. Positive conditions, biomechanically speaking, have to exist in order for propulsive events at the foot/ankle complex. Stability, balance between opposing muscle groups, balance between agonistic muscle/tendon groups, architectural alignments that permit motion (i.e. the windlass mechanism, joint flexibilities, etc.),and kinaesthetic skill sets have to be
in place for safe, purposeful locomotion to occur. We all have viewed the difficulty with locomotion and pain linked with the planus foot that hyper- pronator Ground reaction forces and supinatory moments from a well crafted foot orthosis can provide the balance, verticality of bony alignments in all three planes, and efficient arthrological relationships that precipitate purposeful movement. The normalized foot form yields motion, motion requires power, the need for power builds muscle strength through exercise, strength increases with time yield muscular endurance, and endurance forces adaptations toward efficient and effective gait patterns; function follows form.
by Roger Park, MS, AT-R, CO