Calcaneocuboid distraction arthrodesis for posterior tibial tendon dysfunction and flatfoot - A cadaveric study

Nine fresh-frozen foot specimens were studied to determine the mechanical b ehavior of the foot using calcaneocuboid distraction arthrodesis, an operat ion designed for treatment of posterior tibial tendon dysfunction with flat foot deformity. Flat-foot deformity was created in cadaveric specimens, and to simulate toe-off phase of gait, loads were applied to the plantar surfa ce of the foot and six tendons. Three-dimensional tarsal bone positions wer e determined with a magnetic tracking system. With ligament sectioning, fla tfoot deformity was observed and average arch height decreased 5.3 +/- 3.5 mm, Height arch increased after calcaneocuboid distraction arthrodesis an a verage of 3.2 +/- 3.6 mm and was less than normal arch at an average of 2.1 +/- 2.4 mm, Metatarsotalar alignment compared with flatfoot improved after calcaneocuboid distraction arthrodesis in adduction and inversion to the e xtent that these were not significantly different from intact foot position s. Calcaneotalar position improved after calcaneocuboid distraction arthrod esis in adduction and inversion. Calcaneocuboid alignment compared with fla tfoot improved after calcaneocuboid distraction arthrodesis in adduction, p lantar flexion, and eversion, but compared with an intact foot was overcorr ected in all three planes of motion. Arch alignment in simulated toe-off ph ase of gait in cadaveric feet was improved significantly with calcaneocuboi d distraction arthrodesis but was not reduced anatomically.