Foot Challenges for an Aging Population
By Mark Charrette, DC
As our society matures, the average age of patients is also increasing. If you were to review your current practice, it's likely you'd discover you're seeing more chronic, age-related conditions than you were 10 or even five years ago. It's also likely that your use of posturally supportive products has also been increasing. If that's not the case, then you may be missing some critical factors in treatment and your patients may not be benefiting from your chiropractic care as they should.
With aging, a number of important conditions begin to affect the feet. Some are not immediately symptomatic and patients are often unaware of the deterioration until they develop a loss of functional capacity and independence. Once we begin to pay attention, we will discover a variety of problems in the feet of our aging patients – some biomechanical, others systemic. Many of them can be helped with comprehensive chiropractic care, which often includes stabilizing orthotics.
Weight on the Rise
Depending on the specific population studied and the exact definitions used, most recent research has found that morbid obesity rates are continuing to increase in the U.S.1-2 As we age, we tend to put on more weight. Since the additional weight load places more stress on the supportive skeletal structures, it's not surprising that overweight results in a greater frequency of musculoskeletal and arthritic problems, especially in the knees and feet.
Lower extremity biomechanics are very different in the overweight patient, and many gait changes and abnormalities are commonly seen. During walking, obese individuals take shorter steps, have an increased step width and walk more slowly. They also have increased Q-angles at the knee, more hip abduction, significantly more abducted foot angles and increased out-toeing (foot flare).
Hyperpronation is greatly increased, with a greater touchdown angle, more eversion of the foot, a more flat-footed weight acceptance period in early stance, and a faster maximum eversion velocity being measured. There is also greater ankle dorsiflexion, but less plantar flexion.
Joint degeneration becomes much more prevalent as we age. In the feet, the small joints are exposed to high forces over many years. While the causes of joint degeneration and osteoarthritis are still debated, several studies have clearly demonstrated that repetitive impact loading from a variety of sources results in the development of osteoarthritis.3-4
When a joint is exposed to cyclic impact forces, the appearance of degenerative changes is only a question of time.5 These repetitive forces cause a "fatigue-failure" in the joint tissues, a well-known phenomenon that includes alterations in both the articular cartilage and the cancellous subchondral bone. When this type of intermittent dynamic loading is combined with biomechanical faults, previous injury to a joint or a rigid, non-yielding walking surface, degenerative changes progress rapidly and symptoms frequently develop.
Plastic Deformation and Breakdown
Over periods of years or even decades, repetitive stresses and normal forces result in a slow breakdown of support for the bones and joints of the feet. It is the connective tissues (collagen and proteoglycans) that are exposed to these long-term lengthening forces, resulting in a decrease in elasticity and a sagging of the foot's arches. This breakdown then allows transmission of abnormal strains into the legs, pelvis and ultimately the spine.
Since it is usually the spinal symptoms that have brought the patient into the chiropractor's office, the doctor must be able to identify the underlying foot dysfunction.
The tissues that must withstand this strain for years are the connective tissues (ligaments, tendons and fascia), which are composed primarily of woven collagen fibers. This arrangement allows for the combination of flexibility and strength that keeps our joints within close alignment, while still allowing for a wide range of movement.
The woven collagen fibers demonstrate a very important physical property – viscoelastic behavior. Viscoelasticity is the time-dependent response of tissues to a load.6 The longer a load is imposed on the tissues, the more likely that there will be enough stretch to result in a permanent lengthening.
The result in many aging patients is a loss of the elastic support for the arches of the foot and less shock absorption from the heel pads. Providing stabilizing orthotic support for the aging foot's arches can help prevent problems such as plantar fascitis and heel spurs, which often develop as the foot ages.
An additional recommendation for aging patients with loss of heel-pad compliance is the use of a heel cup, which improves heel-pad function by preventing lateral and medial bulging, thereby maintaining pad thickness.7
Challenges We All Face
The aging of our population provides us with new challenges. Many of the chronic conditions reported by older patients will respond best when their chiropractic care is augmented by adequate and appropriate postural support. With new materials and innovative construction techniques, stabilizing orthotics are now being designed to meet the needs of this growing segment of our communities.
When your "more mature" patients get relief from their chronic, degenerative conditions under your care, they'll help build your practice with referrals. The use of orthotics will often complement and improve the chiropractic adjustment, while assisting the body to return to an improved state of function and health.
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