Loose Hip Research Articles

Metastatic non-Hodgkin's lymphoma on bone scintigraphy mimicking loosening or infection of hip prosthesis.

This case presents an unusual pattern of tracer uptake suggestive of a loose hip prosthesis during Tc-99m MDP bone scintigraphy for metastatic non-Hodgkin's lymphoma.

Soft Tissue Sarcoma Associated with Aluminum Oxide Ceramic Total Hip Arthroplasty

Malignant tumors around fracture fixation implants have been reported sporadically for many years. Recently, however, reports of sarcomatous degeneration around a standard cemented hip arthroplasty and around cobalt-chromium-bearing hip arthroplasties raise new questions of the malignant potential of metallic ends prostheses. Sarcomatous changes around aluminum oxide ceramics seem not to have been reported in the literature. The present report may be the first documented case of an aggressive soft tissue sarcoma detected 15 months after the patient had an uncemented ceramic total hip arthroplasty. If a causal relationship exists, the incidence of this phenomenon in the United States is 250 times greater than would be expected from statistics on soft tissue sarcoma at the hip. Because of the similarity on plane roentgenograms of this tumor to lesions known to be caused by wear debris, tumors should be included in the differential diagnosis of cases of total hip loosening.

Estradiol Induced Skeletal Changes

Beagle pups were injected with 200 mug estradiol benzoate per kg body weight daily 5 times weekly during the first 8 weeks of life. The skeletal development of the pups was followed from 8 weeks to 18 months of age. The femoral heads were smaller and the hip joints more unstable in these pups than in controls from 10 weeks of age. The femoral head ossification center increased more rapidly in size in these pups. The bone mass was also increased. Pups of pregnant bitches, which were injected with estradiol benzoate during the last three weeks of gestation, were studied. The highest total dose injected to the bitches was 90 mug per kg bodyweight. Changes in the hip joints such as small femoral heads and increased instability were found in these pups at 8 and 10 weeks of age. Bone mass was less in these pups than in controls. In adult life these pups had loose hips but they did not develop the complete picture of hip dysplasia. The present investigation demonstrates that the early changes in the hip joints caused by estradiol lead to hip dysplasia.