Although there are fewer instances of high arches than flat feet, it is important to understand the essentials in detection and management of excessive supination.

The most commonly detected defect in foot alignment is overpronation where the longitudinal arch is flattened and the rearfoot overpronates. What about the other type of foot posture? Excessive supination, or high arched feet, are not nearly as common as overpronated feet. The ratio of overpronation to excessive supination is about 9:1.1 Cases of excessive supination do, however, present regularly at chiropractic practices.

Postural stability and dynamic movement begin with the gait cycle. Foot posture and alignment are a critical first link in the kinetic chain. Understanding these postural deficiencies greatly enhances chiropractic management. The use of orthotic devices can also provide the patient with specific support in their subluxation-based care plan.

High Fives
The clinical name of pes cavus literally means a foot with a cave. There is excessive elevation to the longitudinal arch of the foot, and the toes may be drawn into the hammer position. The cavus foot can be quite painful. Its rigid nature forces a clawing of the toes and a redirection of forces to the metatarsal area. Poor shoe fit in both the toe box and along the dorsum of the foot are consistent with these patients. The gait dynamics can be significantly altered and a resultant metatarsalgia can emerge. A quick evaluation of the sole will likely reveal increased callous formation over the fourth and fifth metatarsal heads.

The excessively supinated foot cannot easily move into pronation at heel strike. The rigid foot posture results in a more stressful heel strike and a less accommodating foot on irregular terrains. As these impacts are translated through the biomechanical chain, other structures are affected by the increased shock. Pes cavus is viewed as a contributing component in the development of idiopathic scoliosis.2

In the chiropractic model, the mechanical forces are poorly distributed, and a resultant change can progress in the spinal pelvic alignments. Ultimately, a torsioned and unbalanced posture can ensue. The rigid, supinated foot is actually more unstable than an overpronated or normally aligned foot, and there is greater risk for inversion ankle injuries as a result of this instability.

On Your Toes
The high-arched foot also places the first metatarsal in excessive plantar flexion. This altered joint position disturbs the natural, fluid transfer of forces in the midstance phase. Stress is then concentrated over the first metatarsal head just before toe-off. There is normally eversion of the calcaneus upon heel strike. In the cavus foot, this is replaced by an inversion of the calcaneus.

Imagine the instability that patients feel when the combination of inversion, rigidity, and poor shock absorption occur at the same time. In fact, high-arched feet increase the incidence of inversion sprains to the ankle3 and make the individual more susceptible to stress fractures of the tibia.4

Biomechanical and neurological considerations must be accounted for when evaluating this foot posture. In most cases, the high arch will be a musculoskeletal complication. Often, the patient will report high arches as a family trait. Chiropractors should assess the rest of the kinetic chain for imbalances, restrictions, and compensations. Support and balance are prime considerations for future management, which may include orthotics.

There are, however, serious neurological disorders that present with this foot posture, the most common being Charcot-Marie-Tooth (CMT) disease. This disorder causes the peroneus longus muscle to contract, thus pulling the foot into excessive supination. Spinal neural compression syndromes are important to consider, as are progressive degenerative diseases, such as muscular dystrophies. One study indicated that 60% of all pes cavus deformities are of neurological origin.5

The high-arched foot may appear shorter than usual. This is because the excessive arch uses up foot length. The patient will also have a palpably rigid foot. Joint play and motion palpation will usually reveal multiple fixative regions in the fore-, mid- and rear-foot. A “peek-a-boo” sign may also be present on observation. When the foot is inspected from the front, the medial portion of the heel pad is seen to “peek out” from the border of the foot. This is because the supinated foot usually has developed an inverted calcaneus.

The tendency in management of the high-arched foot is to fill the “cave” with rigid support. The difficulty with this approach is that an already stiffened foot can become more inflexible. According to Arthur Manoli, MD, “These rigid conforming orthoses actually make the problems of foot stiffness and reduced shock absorption worse.”6 A flexible orthotic with proper calcaneal posting to reduce inversion is advised, and shock absorption is a key consideration.

If the Shoe Fits
DCs can provide insight as to the shoe style that is most effective for the high-arched individual. In nonathletic shoes styles, a proper choice should include a flexible sole and ample room in the toe box region to accommodate the clawing or hammering of the toes. A forgiving lacing system would also be beneficial, so patients may loosen the tension across the dorsum of the foot.

Chiropractors can also provide assistance in stretching and retraining of the lower leg, foot, and ankle. Due to the rigid nature of the supinated foot, specific mobilizations and adjustments can be directed to the affected arches. Patients should be encouraged to stretch the calf muscles, as well as the tibialis anterior and the peroneal group. Global stretching and strengthening programs for the entire kinetic chain are necessary to provide continued stability. Remember, the supinated foot is only one link in the kinetic chain. CP

David S. Fletcher, DC, FCCSS (C), a Fellow of the College of Chiropractic Sport Sciences (Canada), has been in private practice for 22 years at The Fletcher Clinic, Pickering, Toronto, Canada. He is recognized internationally for blending traditional chiropractic principles with contemporary technologies and strategies. Fletcher can be reached at 905-831-9696 or via email: fletch5@rogers.com.

References
1. Austin WM. What about supination? Orthopedic Notes. 1994;12:1–2.
2. Moe JH. Scoliosis and Other Spinal Deformities. Philadelphia: WB      Saunders Co; 1982:209–212.
3. Barrie JL. Ankle instability in pes cavus. Presented at the British Orthopaedic Foot Surgery Society. 2000.
4. Giladi M, Milgrom C, Stein M. The low arch: a protective factor in stress fracture. Orthop Rev. 1985;14:709–712.
5. Brewerton DA. “Idiopathic” pes cavus—an investigation into its aetiology. BMJ. 1963;2:659–662.
6. Manoli A, Graham B. Cavus foot diagnosis determines treatment. Biomech. 2001;8(1):55–69.