Why Do We Overlook Equinus In Patients With Diabetes?
- Patrick DeHeer DPM FACFAS
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I find the extent of preventative care we provide for our patients with diabetes fascinating yet we continually ignore one of the most important factors in keeping our diabetic patients out of trouble. Equinus has been described as the most destructive force on the foot and even though we all know this, when it comes to our patients with diabetes, we often overlook equinus and concentrate on those mycotic toenails.
Why is this the case? Is it because we do not think that equinus is really that big of a deal? If that is the case for you, pick up a journal and read up on equinus. Your patients will thank you later.
Is it because we think this group of patients function at a low level and the effect of equinus is minimal? This is absurd. Why do they develop so many pressure related pathologies? How hard is it to get them off their feet when they have an ulcer or acute Charcot deformity? This will clarify their actual level of activity.
Could it be that we are just lazy? Do we feel that debriding their nails and calluses, sticking them in diabetic shoes and orthoses, and educating them about their feet is enough? I am sorry but as the kids say nowadays, really?
I want to discuss a couple of critical articles, which you have hopefully run across somewhere along the line. If not, please read them. (Oh, by the way, I am convinced that the lazy thing is the problem.)
What The Literature Reveals
I think most of the population has equinus. Interestingly enough, patients with diabetes are even more likely to have equinus. In 1997, Grant and colleagues examined the effects of diabetes on the Achilles tendon with an electron microscope.1 They took Achilles tendon samples from 12 patients with diabetes and five non-diabetic patients with foot pathology undergoing foot surgery. Researchers subsequently examined these specimens under an electron microscope. The findings showed the patients with diabetes had increased packing density of collagen fibrils, decreases in fibrillar diameter and abnormal fibril morphology. The theory for these findings is non-enzymatic glycation over many years. In the non-diabetics, the fine structure of the Achilles tendon remained normal. These changes in the patients with diabetes lead to extreme shortening of the gastroc-soleus complex. From here, a multitude of problems occur.
What is the big deal when it comes to diabetic patients with equinus? That is what Lavery, Armstrong and Boulton examined in their study in 2002.2 They examined 1,666 patients with diabetes over two years, placed patients in risk categories and treated them according to risk-based protocols. The authors defined equinus as ankle joint dorsiflexion of less than 0 degrees. Their findings showed the equinus group had three times higher peak plantar pressures in the forefoot in comparison to the non-equinus group.
In this study the authors found a 10.3 percent rate of equinus in patients with diabetes. (I think this is easily low because of the study authors’ definition of equinus. Remember, there is no standard definition of equinus.) Patients with equinus also had a significantly longer duration of diabetes than those without equinus.
Is that enough evidence-based medicine for you? I have shown you why equinus develops in the patient with diabetes and what this can lead to with two excellent studies. Now let us move on to a call to action for you when you are treating all your patients with diabetes.
Examine them for equinus correctly with the subtalar joint in neutral position and the midtarsal joint locked with the knee extended and flexed. Have a standard definition you are going to use for defining equinus. I would suggest Sgarlato’s definition of less than 10 degrees of dorsiflexion.3
Place these patients in standard risk categories and treat them accordingly. Here is the kicker. If the patient has equinus, treat the equinus also. I know it is earth shattering and maybe a little radical, but trust me on this one.
I suggest bracing therapy for equinus (I will have much more to say about this in another blog). Brace patients until they are stretched. Then continue to check them to make sure they are staying stretched and do not require subsequent treatment. Best wishes and stay diligent in what you do.
1. Grant WP, Sullivan R, Sonenshine DE, et al. Electron microscopic investigation of the effects of diabetes mellitus on the Achilles tendon. J Foot Ankle Surg. 1997; 36(4):272.
2. Lavery LA, Armstrong DG, Boulton AJ. Ankle equinus deformity and its relationship to high plantar pressure in a large population with diabetes mellitus. J Am Podiatr Med Assoc. 2002; 92(9):479.
3. Sgarlato TE, Morgan J, Shane HS, Frenkenberg A. Tendo Achilles lengthening and its effect on foot disorders. J Am Podiatry Assoc. 1975; 65(9):849-71.