Gait was analyzed through kinetic, kinematic, and temporal-distance parameters assessment to evaluate the functional performance of ten children treated by the classical Van Nes rotationplasty (VNR). Van Nes rotationplasty is a surgical procedure, which permits the conversion of the ankle joint into a “pseudo-knee” joint. The data were compared with measurements of a normal population of ten healthy subjects. Significant differences with respect to the normal were found in stride duration, stride length, cadence, velocity, and stance-swing ratio, and in ground-reaction forces parameters, which define the propulsive phase in the prosthetic side and the acceptance phase in the sound side. There were differences in some kinematic parameters as well. Van Nes rotationplasty is acceptable from a biomechanical-functional point of view, particularly with respect to the active control of the pseudo-knee, which allows a smooth and coordinate gait pattern.