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PhD Defence Bob Giesberts

Ponseti's clubfoot treatment: a method in need of correction?

Bob Giesberts is a PhD student in the research group Biomechanical Engineering. His supervisor is prof.dr.ir. G.J. Verkerke from the faculty of Engineering Technology (ET).

A clubfoot is a congenital deformity of the foot. It is often treated with the Ponseti method which consists of weekly manipulation and the application of a plaster cast to gradually correct the position of the foot. This method is highly effective, but since it is applied in the first weeks after birth, the plaster casts are inconvenient for the parents making bathing impossible and cuddling unpleasant. Additionally, literature suggests that the treatment can be accelerated without harmful effects.

An instrumented rubber clubfoot model was made to quantify the forces in the Ponseti method. This test showed that the applied forces vary a lot among physicians. A force sensor was developed to measure how these forces on the clubfoot change over time as a result of tissue adaptation in the clubfoot. In all measurements the applied forces gradually decreased to reach an equilibrium within several hours, questioning the validity of the currently accepted weekly cast change interval. Another observation was that the evaporation of the excess water from the plaster casts cause an uncomfortable temperature drop that lasts for 12+ hours. These findings suggest that despite being highly effective, the Ponseti method is not perfect and should be improved.

Concepts for a dynamic clubfoot brace are developed as a possible alternative treatment. Such a brace would closely follow the Ponseti principles but, rather than applying a constant position with a plaster cast, it would apply a constant low force to co-adapt with the clubfoot. We hypothesize that with such a brace initial correction can be achieved within a week. It has a softer look and feel and can be temporarily taken off to allow easy diaper changes and bathing. More work and research is needed to validate the design and test its efficacy.