Emphasizing Proactive Gait Assessment In Patients With Diabetes
When it comes to diagnosing and treating lower extremity issues in patients with diabetes, a thorough biomechanical evaluation is at the top of the list. More often than not, a current ulcer began as a superficial hyperkeratosis, which unfortunately developed in a patient whose ability to perceive the pain normally associated with such a lesion in a timely manner was compromised due to neuropathy. Progression of the disease not only destroys the protective response but ultimately has an adverse impact on the deep proprioceptors that surround the joints, which may lead to the development of a Charcot deformity.
While we can certainly treat the diabetic foot ulcer, as podiatrists, we also need to be more proactive in working up the patient with diabetes who has not yet developed an actual tissue defect.
Diabetes impacts a patient’s neurovascular status in a significant manner. Specifically, peripheral neuropathy in patients with diabetes mellitus increases the risk of foot ulceration sevenfold and, in turn, contributes to considerable morbidity.1,2 Patients with diabetic neuropathy may have large fiber or small fiber neuropathy. According to Kanji and colleagues, large-fiber peripheral neuropathy often occurs in the insensate foot and patients may be unaware of their condition.3 This is the neuropathy of concern when evaluating gait as it is related to loss of pain and proprioception.
Various researchers have attempted to discover the pathophysiology behind the development of diabetic neuropathy. Multiple studies have concluded that neuropathy is the result of vascular endothelial dysfunction. LaFontaine and co-workers noted that in diabetes, compromised endothelial function has been implicated in microthrombus formation, ischemia, neuropathy, an increased risk of atherosclerosis and hypertension.4
The concept of a hyperkeratotic lesion eventually breaking down into an ulceration due to neuropathy has been well documented. However, in addition to performing a neurovascular exam, analyzing a patient’s gait is critical to understanding the reason behind the callus formation and patterns. According to Lavery and colleagues, pressure sites exposed to repetitive trauma produced during normal walking are predisposed to injury and ulceration.5 A study by Mueller and co-workers showed that analysis of the walking patterns of patients with diabetes may lead to a better understanding of the mechanics of gait and to treatments to reduce the number of injuries in this patient population.6
Key Clues That Signify A Loss Of Proprioception
Proprioception is the sense of the position of parts of the body relative to other neighboring parts of the body. Proprioception signals are carried from stretch and tension sensors in the muscles through the nerves to the brain, and can be interrupted in patients with poorly controlled diabetes.
Patients with diabetes who have a loss of proprioception may have symptoms of falling down while walking. Often, one may find these patients focusing on a distant object for balance or looking down at their feet for visual cues during walking to compensate for their loss of proprioception.
According to Levin and O’Neal, the widely agreed upon role of sensory feedback in gait does not apply to the patient with diabetes.7 Richardson and colleagues found that patients with diabetic neuropathy exhibited increased variability in step width and other gait parameters in poorly illuminated settings.8 They have also demonstrated that challenging environments (irregular surfaces and low lighting) magnify gait differences between older women with and without peripheral neuropathy that are correlated with the severity of peripheral neuropathy.9