Quantifying the Ponseti method.

The Ponseti method is the accepted treatment of idiopathic clubfoot. Although the method of manipulating the baby feet is described in great detail, current study aimed to investigate the magnitude and course of the applied forces in order to optimise the treatment of clubfoot. An instrumented clubfoot model was constructed with force sensors on the location of the first metatarsal (FM) and the talar neck (TN) and treated with the Ponseti method by 17 practitioners. Applied forces on FM and TN were measured during manipulation (4.2N; 12N), during casting (3.2N; 3.5N) and after casting (2.9N; 2.2N). The forces during manipulation were significantly higher than during casting on TN (p<0.001) but not on FM (p=0.129). No 'correct' amount of force could be determined and inter-practitioner variability was measured to be 70%. The resulting pressure of the cast on the clubfoot model as measured directly after casting was significantly higher than local tissue perfusion. The results of this study suggest potential for the optimisation of the application of the Ponseti method.