We explore the relations among quadratic modules, 2crossed modules, crossed squares and simplicial groups with Moore complex of length 2. Introduction Crossed modules defined by Whitehead, [23], are algebraic models of connected (weak homotopy) 2-types. Crossed squares as introduced by Loday and GuinWalery, [22], model connected 3-types. Crossed n-cubes model connected (n + 1)types, (cf. [21])....

Background:Locking plate fixation is increasingly used for first metatarsophalangeal joint (MTP-I) arthrodesis. Still there is few comparable clinical data regarding this procedure. Methods:We retrospectively evaluated 60 patients who received an arthrodesis of the MTP-I between January 2008 and June 2010. With 20 patients each we performed a locking plate fixation with lag screw, arthrodesis w...