[Comments on the double-cup hip endoprosthesis according to Freeman (author's transl)].

Histological examinations (including tetracycline labelling) of preparations of the neck of the femur which had to be removed 1 1/2, 3 and 14 1/2 months subsequent to double-cup arthroplasty according to Freeman, prove that the bone tissue can remain vital under the solidly cemented metal cup. A thick layer of connective tissue with bundles of collagenous fibres running parallel to the surface, is temporarily formed between the cement layer and the prepared spongiosa of the neck of the femur. It is possible that this layer of connective tissue is replaced within about a years' time by a thin, lamellar cortex layer, which is then covered only by a thin layer of connective tissue which is rich in fibres. Below this layer, the spongiosa spaces are definitely widened and filled with fibrotic fat marrow; vascularisation decreases, whereas osteoporosis increases.