Development of the ball-and-socket ankle as assessed by radiography and arthrography - A long-term follow-up report

We studied the development of ball-and-socket deformity of the ankle by art hrography and radiography in 14 ankles of ten patients with congenital long itudinal deficiency of the fibula accompanied by various anomalies. The mea n follow-up was for 18 years 10 months. In three ankles in infants less than one year old the lateral and medial si des of the ankle were already slightly round. In another seven ankles the b all-and-socket appearance developed before the age of five years. This was thought to be due to osseous coalition which limits eversion and inversion. In another four ankles in children who were over the age of one year at th e initial examination, the deformity was demonstrated by arthrography and r adiography at their first examination. Ball-and-socket deformity accompanied by tarsal coalition is an acquired de formity secondary to limitation of movement of the subtalar and midtarsal j oints, It has completely developed by about five years of age.