ORTHOTIC TREATMENT FOR A PERSON WITH OSTEOARTHRITIS USING A NOVEL ARTICULATED SUPRA-MALEOLAR DESIGN.

Gracey, C, Croarkin, E; National Institutes of Health, Bethesda, MD. Cgracey@cc.nih.gov.

PURPOSE: Supra-Maleolar Ankle Foot Orthotics (SMAFO) are used to correct poor bony alignment in the rear foot and eliminate excessive pronation occurring at the subtalar joint. Current designs limit ankle motion in the sagittal plane. An articulated ankle foot orthosis (AFO) can be corrective and allow free ankle movement, but with added size and weight. An orthotic design was developed for a subject who experienced painful overpronation but had pain-free ankle range of motion in both lower extremities. DESCRIPTION: Findings for one female subject, age 71, with a history of osteoarthritis, included: bilateral genu valgum, tibia varum, calcaneal valgum, and subluxed navicular with weight bearing (WB) pes planus. Subject reported 8/10 pain on 0-10 pain scale during brief standing and walking and 10/10 after prolonged WB activity in bilateral medial longitudinal arches, dorsolateral midfoot, and knees. Pain free bilateral ankle dorsiflexion was +15 degrees. Mean in-shoe peak plantar pressures during gait were 10.740N/cm² for left foot (7.760 Standard Deviation (SD)) and 9.939N/cm²(8.760 SD) for right foot. Positive plaster molds were created from deformity corrected, short leg, bivalve casts. Molds were prepared using perforated polyurethane sheets, nylon joint blanks, and foam pads. Braces were assembled using vacuum-formed polypropylene sheets, nylon joints, hook and loop straps, and footplate pads. Top trim-lines remained within the distal 1/3 of the lower leg and were thought to restrict frontal plane movement by extending the effective "lever-arm" above the ankle. OBSERVATIONS: Following fitting and training, subject reported 0/10 pain. Static alignment measures of the feet, ankles, and legs were within normal limits. Mean in-shoe peak plantar pressures during gait were 7.484 N/cm² (3.907 SD) for left foot and 5.921N/cm² (3.223 SD) for the right. This represents a decrease of 30.32% on the left and 40.42% on the right. Patient stated positive comments regarding cosmesis and weight of brace. CONCLUSIONS: This design of an articulated SMAFO corrected malalignment, controlled midfoot pronation, allowed free ankle motion, and relieved painful symptoms. It is an additional therapeutic option to consider for persons with arthritis of the foot. Benefits include improved cosmesis, decreased weight, and possibly reduced costs associated with utilizing a smaller brace. Further research of this design is needed to establish long-term effectiveness across a larger population. FUNDING SOURCE: None.

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