Clinical and roentgenological studies on malalignment disorders of the patello-femoral joint. Part II: Relationship between predisposing factors and malalignment of the patello-femoral joint.

To clarify the relationship between the predisposing factors and malalignment of the patello-femoral joint, a study was conducted on the basis of roentgenograms of 621 cases in which a disorder of the dérangement was suspected in at least one knee. The degree of alignment was classified into four grade groups according to the dynamic skyline view arthrograms. Each predisposing factor was expressed by patellar tendon-patella ratio, patellar facet ratio, depth index, and femoro-tibial axis angle.