Der Effekt der modifizierten Lapidusarthrodese auf den medialen Strahl in der Sagittalebene: erste Ergebnisse einer radiologischen Pilotstudie und biomechanische Grundlagen

An insufficiency of the medial ray can be caused by hypermobility or instability of the medial tarsometatarsal joint. The major function of this joint complex is the load transfer from the hindfoot to the forefoot, so medial tarsometatarsal instabilities can play an important role in hindfoot-pathologies. Stabilization of the medial tarsometatarsal joint can be achieved by arthrodesis. But the effects of the modified lapidus procedure to the longitudinal medial arch and the hindfoot are poorly discussed in literature. Therefore we conducted a pilot study and reviewed 30 radiographs of 26 patients (22 females, 4 males, mean age 61° years) to evaluate structural radiographic changes of the longitudinal medial arch following modified lapidus arthrodesis. The talo-first metatarsal angle, the talus-floor angle and the medial cuneiform height changes were statistically significant. The TMT-Index also improved, but was not statistically significant. These preliminary findings suggest that the modified lapidus procedure can influence the medial longitudinal arch.