Walking the Biomechanical Runway

Depending on the reason for being there, it is not uncommon for part of your visit to the podiatrist to include a gait and biomechanical evaluation. Gait is the way in which someone walks, their swagger. The patient is asked to roll up their pants and walk back and forth, sometimes fast and sometimes slow. The doctor meanwhile intently watches until satisfied and has seen enough. The doc will then proceed to examine you from your hips to your toes, pulling, twisting and prodding on the way down.  During this ritual the doctor is obtaining information to formulate the treatment plan.  The cool thing about a biomechanical approach to the body’s problems is that the goal is to fix the underlying cause of the problem in a completely non-invasive way. Below are a few big concepts involved in a basic biomechanical evaluation.

Bill Cosby's gait evaluation.

1.       Supination and Pronation: These are probably terms that you are somewhat familiar with but let’s just make sure that we are on the same page. Supination is when the bottom of the foot is moving to face the midline of the body also causing the ankle joint to extend and the foot to turn inwards. Correct terms for these movements are inversion, plantarflexion and adduction. Pronation, the opposite of supination, refers to moving the bottom of the foot to face away from the midline of the body, causing the ankle to flex and the foot to turn outwards. Correct terms for these movements are eversion, dorsiflexion and abduction. The ability of the foot to supinate and pronate in necessary in the function of the foot during walking and running. These terms are also used to describe the foot's position while standing.

Figure borrowed from www.orthoticshop.com. 

2.       Asymmetries:  For the most part, the body was designed to be symmetrical, in movement and structure. Asymmetries lead to inefficient movements that put increased amounts of stress on the body’s structures often leading to breakdown, causing pain.

3.       Limited Joint Range of Motion:  Every time a joint comes to its end range of motion the soft tissue is potentially being stretched beyond the point at which it is capable of recoiling.  Abnormal end range of motion also can mean that you are having non-anatomical bone on transferred energy and motion that is not dissipated by the proper joint. Simply put, the jarring of joints is bad.

4.       Pronation Affects the Entire Body: Pronation, the lowering of the foot’s arch, causes the tibia to internally rotate and is a mechanism that the body uses to shorten an elongated limb. Try it. Stand up and try to pronate your foot while standing. The only way that you can do it is by internally rotating your leg forcing you into a knock-kneed type stance. This internal rotation translates up the leg all the way to the hip leading to tilting of the pelvis. This tilting affects the spine and up to the shoulders. This path of misalignment has been shown to cause a whole host of problems, including but not limited to: patellofemoral pain syndrome, iliotibial band friction syndrome, ACL injuries, sciatic pain, and lower back pain. Pronation also decreases the amount of upward bend (dorsiflexion) in the big toe which over time can lead to bunions and osteoarthritis. 

The Vitruvian Man, 1485. Leonardo da Vinci

Often times only parts of the exam will be conducted depending on the problem and each doctor has small differences in the way in which the information is obtained. Treatment recommendations to improve the biomechanics of the foot include strengthening specific muscles/muscle groups, orthotics and shoe types.

Insoles, Arch Supports, and Orthotics

Inserting things into shoes to reduce pain is not uncommon. The only problem is that there are so many options currently available that it is difficult to determine what exactly will give the most relief. Shoe inserts can be divided in to three basic types; insoles, arch supports and orthotics. Understanding the differences will allow those seeking relief to make a more educated decision, leading to a better chance of obtaining pain relief.

Insoles

Insoles are what most people think of when they think of shoe inserts. They come in all sorts of materials from gels to foams to air pouches and usually have a small cutout in the packaging that says “Try Me” or something similar. This type of insert doesn’t change the alignment of the foot but rather just adds padding. Cases in which this may be beneficial include pain under the balls of your feet or the heel due to the breakdown of the fat pads. Fat pad break down is caused by various reasons including aging and genetics. Foot types that often show pain in this area are ones that have a very high arch.

When choosing a padded insole I would suggest picking one that has an open cell cushioning system as opposed to a closed cell. This would include materials, such as foams, that upon compression allow rapid collapse of air cells. Closed cells such as gel inserts or air pouches only displace the gel or air within the material not allowing total collapse of the material. While pushing on the gel slowly with your finger might feel great, repetitively walking on a material that doesn’t respond quickly to your foot strike will not be as comforting.

Arch Supports

Arch supports are much stiffer than insoles. While they can have a padded type covering, they are more rigid. These supports come in various sizes and offer relief by pushing up the arch of the foot.  Often times foot pain can be attributed to a flattening arch and supporting the arch can offload some of the ligaments and tendons that may be causing the pain.  These inserts however are not custom and therefore it is not possible to get a support that fits your foot exactly.

***Obtained this SOLE video from www.zappos.com. The guy states that these offer "the most custom support possible". While they are more custom than many others, I would have to say that they don't hang a hat to doctor prescribed orthotics.

While there are a lot of arch support type insoles on the market the two above, Superfeet and SOLE, are good options. They run about $40 a pair and last anywhere from 6 months to a year.  Anything that supports the arch is moving in the right direction.

Orthotics

Orthotics, more properly known as custom foot orthosis, have been defined as “an orthopedic appliance or apparatus used to support, align, prevent, or correct deformities or to improve the function of movable parts of the body”.  These devices are custom made to fit your feet and can be modified to target specific pathologies and deformities.  Holding the foot in proper alignment with the body has an effect on the entire limb. Orthotics are prescribed for pain in all joints associated with the lower extremity  including hip, knee, ankle and big toe joints and can even reduce back pain. Orthotics also reduce strain on tendons and ligaments in the foot which can reduce inflammation and swelling, allowing the body to heal damaged tissue. These orthotics last anywhere from 5-10 years and can be modified or refurbished as needed. They cost $300 and up depending on the area.  This seems like a lot but if one decides to go with the over the counter non-custom arch support, at $40 every 6 months, you will be paying around $400 for five years of comfort and support. Orthotic coverage by insurance is plan specific.

The type of device right for you is dependent on the severity of your problem, your activity level, shoe type, foot type, body type and many other factors. By consulting with your podiatrist you can find the right solution.