Understanding And Managing Equinus Deformities
If the aforementioned survey results are representative of the entire profession, then it is impossible to attribute the relative lack of surgical treatment to diagnosis, recognition and understanding the condition. Even as early as 1971, Subotnick boldly and accurately stated that equinus “is the greatest symptom producer in the foot.”2
Consider the following compelling facts.
• Equinus is the single biggest risk factor for plantar fasciosis with a 23.3-fold odds ratio for the development of the condition.5
• DiGiovanni’s 2002 study showed that 88 percent of patients with foot pathology have equinus.1
• Bowers and Castro clinically observed a 50 to 60 percent incidence of equinus in all patients examined for any foot or ankle problem.6
• Hill found that 96.5 percent of patients who presented with foot pain had equinus.4
• Increased tension in the Achilles tendon transfers directly to increased tension in the plantar fascia.7
• Lavery, Armstrong and Bolton evaluated 1,666 consecutive patients with diabetes and found those with equinus (and their definition of equinus was 0 degrees of dorsiflexion) had a threefold chance of increased peak plantar pressures, which are known to increase the chance of ulceration.8
• In 30 children with neuro-spasticity who were initially evaluated and noted to have no foot deformity prior to weightbearing, 19 developed hallux valgus after walking while the other 11 developed an adducted forefoot.9 This evidence alone provides an irrefutable demonstration that equinus is a causative factor in the development of forefoot pathology.
Yes, there is the argument for conservative care. However, when gastrocnemius equinus is significantly present with an associated formidable forefoot global deformity, is there really anything conservative about performing an extensive forefoot reconstruction without addressing the tightness of the posterior superficial compartment of the leg?
Grady and Saxena showed an improvement of only a few degrees after different levels and times of stretching of the gastrocnemius muscle.10 Evans in fact showed that only six of 20 patients were able to reach 10 degrees of dorsiflexion after use of night splints ranging from six weeks to one year.11
This brings to light two important questions. Aren’t those patients with significant demonstrative pathology likely to need more than 3 degrees of improvement in dorsiflexion to ameliorate their mechanical overload? Do we really need to stretch the muscle or the aponeurosis? The tensile strength that would be required to stretch the aponeurosis would far exceed the force required to maintain normal ligamentous and tendon integrity of the midfoot during the stretch.12
Key Surgical Considerations
Historically, the surgical paradigm to treat equinus, although well delineated, has not evolved to correlate with the improvement in current surgical techniques.
Equinus can be difficult to measure or assess clinically from practitioner to practitioner. As DiGiovanni points out, clinicians are accurate 97.2 percent of the time if equinus contracture is defined as less than 10 degrees of dorsiflexion.13 Accuracy falls to 77.8 percent if 5 degrees is the benchmark. From a pragmatic point, in addition to the vast amount of literature, which supports the need for 10 degrees of dorsiflexion at the level of the ankle joint for normal biomechanical function, clinicians would obviously be more accurate in assessing whether the patient has less than 10 degrees of dorsiflexion with the knee extended.