Medial arch strain after lateral column lengthening: An in vitro study

Posterior tibial tendon dysfunction with concomitant progressive flatfoot d eformity is associated with ligamentous failure along the medial arch. Late ral column lengthening is being used alone and in combination with other pr ocedures with the expectation that it contributes to restoring and maintain ing the arch. The primary objective of this study was to examine the effect of lateral column lengthening on medial arch strain, A secondary objective was to examine the effect of subtalar, talonavicular, double and triple fu sions on medial arch strain, Whole cadaver feet were subjected to Vertical loads while in a plantigrade position. Spring ligament length was monitored using liquid metal displacement gauges. Two outcomes were examined: the le ngth of the ligament and the change in length of the ligament per unit of a pplied load. Ligament length was unchanged after lateral column lengthening , Ligament length was decreased after talonavicular, double and triple arth rodeses, consistent with the ligament being protected by these fusions, The change in length per unit of applied toad after simulated lateral column l engthening was comparable to that for the intact foot, which is consistent with the ligament remaining functional during weightbearing and not being o verloaded.