In about 50% of cases, osteonecrosis of the femoral head is known to occupy more than one site. There is controversy as to whether a single focus may increase in size. We have reviewed 606 consecutive femoral heads which had been surgically removed for osteonecrosis. Extension of osteonecrosis was observed in only two (0.3%) and was confirmed histopathologically by the enlargement of the necrotic segment beyond the repair zone formed for the primary necrosis into the adjacent, previously uninvolved bone. In both cases, the necrotic regions were wedge-shaped and occupied over 80% of the femoral head. It appears that an increase in size is extremely rare and that osteonecrosis is due to a single event. Our findings may be of value in assessing the use of joint-salvage procedures for osteonecrosis of the femoral head.
1. The orientation of collagen fibres of the menisci of the knee has been demonstrated by polarised light microscopy. 2. As might be supposed from its fibre structure, the ultimate tensile strength of the meniscal tissue is dependent upon the axis of loading. 3. The tensile strength of the meniscus is similar to that of articular cartilage.
1. A method is described for the 2. The osteogenetic potential of a variety of substances can also be investigated by this method. The tissue in the chamber can easily be prepared for its final examination by optical and electron microscopy and by other laboratory techniques.
1. Of forty-seven patients with histologically proven myeloma of the spine, thirty-three had multiple lesions at the time of the first examination and fourteen were solitary. 2. Five of the solitary cases, in which the patients are alive and well without signs of dissemination four to fourteen years after diagnosis, are considered in detail and the differences in clinical presentation and prognosis are discussed. 3. A sixth case, described in detail, showed scattered osteolytic lesions after ten years.
1. The age changes in the articular cartilage of the elbow joint are presented from a study of twenty-eight necropsy subjects aged eighteen to eighty-eight years. During early adult life those areas of cartilage which do not usually articulate with opposed cartilage always show some degree of chondromalacia. 2. Evidence is presented that the almost inevitable degeneration of the radio-humeral joint in old age is related to the combination of rotation and hinge movements that occur at that joint. This is in marked contrast with the relative immunity of the humero-ulnar articulation which has hinge movement only.
