Researchers at the Hospital for Special Surgery (HSS; New York, NY, USA) developed the new procedure, which not only reconstructs the flat foot deformity, but also reconstructs the deltoid ligament, a strong, flat triangular ligament that is located on the inside of the ankle that provides support to prevent the ankle from overpronating. In severe adult flat foot deformity, the deltoid ligament has become stretched and incompetent, which then allows the ankle to tilt. To perform the surgery, the researchers use a tendon that runs along the outside of the calf called the peroneus longus, or alternatively a cadaver ligament. The researchers have already performed the surgery in five patients (four men and one woman, mean age 67 years).

Following surgery, the patients were able to walk an average of 25 city blocks, equivalent to two kilometers. Two patients continued to play golf without significant problems, another exercised regularly on a treadmill, one was involved in circuit training, and the final patient played volleyball, although he did notice some stiffness. All patients reported they were satisfied with the procedure and, given the result, would have the operation again. The patients also underwent X-rays that showed the surgery improved the alignment in the ankle, and the effects were long lasting; the patients had excellent mobility at eight to 10 years following the surgery, and none of the patients had arthritis. The study was presented at the annual meeting of the American Orthopedic Foot and Ankle Society (AOFAS), held during July 2010 in National Harbor (MD, USA).

“Before this study, we were not sure whether you could salvage patients with flat foot and ankle deformity and correct their ankle as well as their foot deformity,” said senior author Jonathan Deland, M.D., chief of the department of foot and ankle surgery at HSS. “Now we know that with this technique you can save the ankle, and it provides a correction of the deformity even at nine years after surgery.”

Adult acquired flat foot deformity is a severe type of flat foot that develops for unknown reasons in individuals who have had flat feet all their life. It is more prevalent in women and those who are overweight, and it usually develops in individuals in their 40s and 50s. In stage I of the deformity, the tendon that runs along the inside of the ankle begins to degenerate. In stage II, the arch starts to fail, and a person develops a more severe case of flat foot. As the arch continues to collapse and the flat foot becomes more pronounced, mobility becomes difficult, and the foot becomes stiff, which is considered stage III. In the most severe stage, stage IV, the ankle starts tilting and is at risk of developing arthritis as a result of the deformity.

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