Development of the functional orthosis.

In conclusion, a functional orthosis may be used to effectively treat most, but not all, abnormalities of the lower extremity that cause abnormal function of the foot. Abnormalities that are resistant to treatment with functional orthoses are compensated talipes equinus, excessive verticality of the oblique axis of the midtarsal joint, forefoot adductus that exceeds 15 degrees of adductus, Charcot's disease, congenital shortage of the iliopsoas muscle, and certain neurologic diseases that exhibit transient muscle spasm or paralysis, resulting in abnormal forces acting upon the foot that vary with time. Unfortunately, laboratories that claim to fabricate functional orthoses may turn out products that vary from nondescript arch supports to orthoses that only partially control function of the foot. The author hopes the practitioner who reads this article will be better able to evaluate whether his or her laboratory is providing his or her patient with a functional orthosis when one is ordered.