Orthotic Modifications for High Arched Feet (Pes Cavus)

Special Topic: Orthotic Modifications for Over Supinated Feet

In most cases I am not designing a foot to correct a “foot type” but to provide a solution for a specific clinical problem. While having a high arched, over supinated, under pronated foot may predispose to certain problems other “foot types” can have many of the same problems.

Some problems that can occur and are related to supination movements (or even “moments”) include:

  •  chronic and repeated ankle sprains
  •  peroneus brevis tendinopathy
  •  peroneus longus tendinopathy
  •  cuboid stress fractures
  • 4th and 5th metatarsal stress fractures
  • 5th metatarsal base or midshaft fractures
  • lateral leg pain (peroneal muscle group)

In many instances with problems like these, immobilization may be necessary for a time. Wobble board training should be incorporated into rehabilitative programs. The purpose of the wobble board training is to have the neuromuscular system adapt the peroneal muscles to performing repetitive firing for stabilization. The angles that the wobble board makes with the ground and the motion and angular relationships that it engenders in your ankle and leg are ideal to training the peroneals to fire appropriately.

The wobble board assists in training muscle strength, balance, and improving joint position sense. There is nothing that beats this 3 in 1 training.

For patients who do not have a dramatic Pes Cavus foot there are a few specific corrections I include in the orthotic:

  • Accurate cast of the foot.
    I do not want a 2D pressure scan. I want to hold the foot in neutral subtalar joint position. And I want to plantar flex the first ray by either light dorsal pressure over the first metatarsal or by slight dorsiflexion of the great toe during the casting.
  • Minimal cast correction.
    I want the cast to reflect the shape of the foot to mirror it so that when I want to alter forces, they will be altered by the shape and adjustments to the orthotic. I want the forces distributed through a large surface area and need conformity between the shape of the foot and the shape of the orthotic.
  • No lateral bevel.no-bevel-post
    This resists over supination directly. It is like an outrigger on a boat. It also changes moments of force going into the foot.
  • 3 degree lateral forefoot wedge.
    This is often used to prevent over supination of the foot after the heel as left the ground or as weight is transferred towards the forefoot.

These are often my starting steps to deal with the problems listed above when they are resistent to treatment.

For a Pes Cavus, high arched, over supinated foot podiatrist Richard Blake, DPM has put a great video on line. It details his 8 steps to deal with this foot type using specially customized orthotics. The modifications made for this problem are not found in over the counter orthotics. And many specialists do not see enough patients with high arches to be adept at treating the problems associated with this foot type. It is important to find a physician that has experience with sports medicine, high arch feet, and biomechanics.
The Blake 8 Steps (only slightly modified) follow:

First an accurate cast is required as described above.

A) Rounding of the lateral border of the cast or via CAD/CAM to have the orthotic better grip the foot.
B) Lateral Kirby Skive. Often 2 to 4 mm.
C) Deep Heel Cup – up to 25 mm.
D) Extended lateral heel cup or “lateral flange”
E) Eliminate “medial heel grind off” and/or add No Lateral Bevel in rearfoot posting instructions.
F) Lateral arch fill to add more surface contact area
G) Narrower orthotic (sometimes) to limit any antipronatory forces. (note: some will go for wide or nomal width for increased stability and contact)
H) Forefoot modifications such as lateral wedgehttp://www.prolaborthotics.com/Products/PathologySpecificOrthoses/LateralAnkleInstability/tabid/138/Default.aspx

Dr. Blake reviews these modifications in a 9 minute video on YouTube: https://www.youtube.com/watch?v=hMhrTmWXfDA

This video is well worth watching for anyone who needs the modifications or anyone who is planning to incorporate them into a patient’s orthotics.

Note: Images Courtesy of ProLab Orthotics

High Arches can make you feel like you are heading for your own personal apocalypse. Turn it down and listen to Arch Enemy with some heavy metal:

Or if you feel like stepping out, you can go retro with John Mayall’s Bluesbreakers: