Adult acquired flatfoot deformity at the talonavicular joint: reconstruction of the spring ligament in an in vitro model.

The mobile unilateral flatfoot deformity of chronic posterior tibial tendon insufficiency has been difficult to correct by soft tissue procedures. The procedures can decrease pain, but they do not always correct the longitudinal arch or relieve all the symptoms. Using 10 fresh frozen cadaveric specimens and a rig for stimulation of weightbearing, the deformity associated with chronic posterior tibial tendon insufficiency was produced by multiple ligamentous release and documented by AP and lateral radiographs. Reconstruction of the spring ligament using a ligament bone autograft from the superficial deltoid ligament was then performed and tested under load. The mean correction was within 2.5 degrees of normal (over or undercorrection) on both the AP and lateral radiographs with the specimens under load. Clinical Relevance. In posterior tibial tendon insufficiency, it may be possible to address the ligament as well as tendon insufficiency to gain a corrected arch. The success of such a procedure will depend upon adequate tendon and ligament reconstruction in a fully mobile deformity. Questions remain as to the adequacy of this ligament graft, and a stronger free ligament graft, as well as correction of any bony malalignment, may be required.