cavus foot

The cavus foot or high arched foot, as the name implies is pretty much the exact opposite of a flat foot and because of this has its own inherent set of potential problems. Most people who have high arched feet find this as just part of their normal skeletal structure. However, there are many people who have a cavus foot structure as a result of neurological diseases such as cerebral palsy, Charcot-Marie-Tooth disease, spina bifida, polio and muscular dystrophy just to name the more common neurological causes.

In the case of the neurological origins of cavus foot, this is usually a result of weakening of the muscles that flatten the foot resulting in a relative strengthening of the muscles of the foot and leg that raise the arch. In the case of neurological origins, the high arched foot tends to be a progressive problem usually resulting in some form of bracing to protect against drop foot and to aid in better gait management. Surgical intervention is also likely in many cases in an effort to reduce the effects of the high arch and add more stability to the foot overall.

Most cases of cavus foot deformity seen in the office is of the idiopathic or natural occurring form which in the majority of cases is much less severe that the neurological type. Nonetheless the high arched foot is subject to a multitude of potential problems.

We can generally further divide the idiopathic cavus deformity into two sub-classes: rigid and flexible. In the rigid type of cavus deformity the arch stays virtually the same height whether the patient is on or off his foot. In the flexible cavus deformity, the arch will be very high when a person is off weight bearing , but when they step down, their arch will flatten out to some extent.

This type of foot structure is subject to certain inherent problems. Compared to a more flexible foot, the rigid high arched foot tends to be a very poor shock absorber. One of the functions of the foot during the gait cycle, in addition to getting us from point A to point B is to absorb the shock of the heel hitting the ground and preventing this impact from traveling up the leg to the lower back. Because the rigid cavus foot has very little to almost no subtalar joint motion (the joint just below the ankle joint), the impact of the heel hitting the ground is not absorbed and can lead to problems such as ankle, knee , hip pain, as well as conditions such as ilio-tibial band syndrome.

More local to the foot, the cavus foot deformity can exacerbate certain problems. Lateral ankle sprains are more common in the high arched foot simply because the heel bone (calcaneus) is slightly more tilted inward to the mid line of the body than a "normal" foot structure. This inversion of the heel increases the odds of twisting the ankle.

Looking at the pictures on this page, one can see that the heel and the ball of the foot are subject to greater impact in the high arched foot (red circles). Because of this body weight is not evenly absorbed throughout the foot but rather centered in those two areas. This can lead to conditions such as capsulitis , metatarsalgia ,sesamoiditis , severe calluses on the ball of the foot as well as hammertoe deformity (blue arrow). Hammertoes develop as a result of the toes riding up on the metatarsal heads due to the high angle that is formed at the height of the arch.

Treatment for either the rigid or flexible cavus deformity generally requires the use of an orthotic . The problem here is that most store bought arch supports are not high enough to even come close to supporting the arch. The purpose of an orthotic in these cases is to more evenly distribute body weight across the whole foot and reduce the pressure on the heel and the ball of the foot. By evenly distributing body weight, the foot is able to function more normally and most of the problems mentioned in this article can be reduced or even eliminated.

Shoe selection also becomes an issue in the very high arched foot. Most people with very high arches cannot wear shoes like loafer or non zippered boots as they simply cannot get their feet into those types of shoes. A good conservative laced shoe is a better choice.