[Ankylosis in the lower limb in ankylosing spondylitis].

Synostosing ankylosis of lower limb joints was investigated radiologically and clinically in approximately 2000 patients with ankylosing spondylitis. Ankylosis was found in 8 hip joints and in 4 of the joints of the foot skeleton. Most commonly the initial picture of these diseases is that of an arthritis (sometimes specifically misinterpreted as such) years and decades before the manifestation of ankylosing spondylitis appears. The ossifying potential of the disease can apparently manifest itself early in limited areas. The radiological morphology with destruction and reconstruction is found mainly as the well known vertebral changes. Immobilization can at the most be regarded as a favourable factor in a predominantly immunological-inflammatory patho-mechanism. Additional local abnormalities of the vascular or enzymatic systems of the joints can be assumed.