Familial joint laxity and recurrent dislocation of the patella.

Recurrent dislocation of the patella probably has several causes. In many patients abnormal laxity of the knee is present and this may predispose to dislocation (Dc Palma 1954). A family has come to our notice in which three members suffered recurrent dislocation of the patella and a fourth had probably sustained a single dislocation. All the former had abnormally lax knees and most other joints showed similar hypermobility. Five other living members of the family were also “double jointed” but had not suffered dislocation. The particular interest of the patients we shall describe lies in the association of familial joint laxity with recurrent dislocation of the patella.