[Subchondral cysts of the iliac acetabulum (author's transl)].

Subchondral solitary bone cysts occur, as well as in numerous other places in the skeletal system, also in the roof of the acetabulum. These cysts differ from typical arthrosis growelcysts in form, position and X-ray appearances. They can be found in hips otherwise normal on X-ray examination (Group I), or in the presence of prearthrosis or arthrosis (Group II). The clinical features and the pathological anatomy of this form of bone cysts are discussed, as well as its aetiology. The pain precipitated by these cysts is very favorably affected by operative filling of the cyst with autologous spongiosa, as shown by follow up of the 19 operations done by the authors. These operations were done on an average 7 years previously. The result was good or satisfactory in 17 out of these 19 cases. The 2 treatment failures were due to wrong indication for operation--the simultaneous arthrosis was already too advanced. The authors prefer for this operation the Watson-Jones approach and recommend, if a large acetabulum-roof-cyst is present, immediate filling of the cyst also if an intertrochanteric osteotomy is done at the same time because of prearthrosis or arthrosis.