Transient osteoporosis of the hip misdiagnosed as osteonecrosis on magnetic resonance imaging.

A 34-year-old man developed idiopathic, bilateral, asynchronous transient osteoporosis of the hip. The symptoms included hip pain with activity, and roentgenography revealed osteoporosis of the femoral head and neck. Radionuclide bone scans showed increased uptake of the involved femoral head. Magnetic resonance imaging (MRI) early after the onset of right-side symptoms was characterized by decreased signal intensity on T1-weighted images and patchy areas of increased and decreased signal intensity on T2-weighted images; this was initially interpreted as being consistent with osteonecrosis. Despite evaluation by multiple physicians and imaging methods, including MRI, the correct diagnosis of transient osteoporosis of the hip was delayed until after resolution of the syndrome. Transient osteoporosis of the hip should be included in the differential diagnosis of hip pain.

Evidence for ammonium-bearing minerals on ceres.

Spectra obtained from recent telescopic observation of 1-Ceres and laboratory measurements and theoretical calculations of three component mixtures of Ceres analog material suggest that an ammoniated phyllosilicate is present on the surface of the asteroid, rather than H(2)O frost as had been previously reported. The presence of an ammoniated phyllosilicate, most likely ammoniated saponite, on the surface of Ceres implies that secondary temperatures could not have exceeded 400 kelvin.

Neovascularisation of the meniscus with angiogenin. An experimental study in rabbits.

Angiogenin, a potent blood vessel inducing protein, was implanted into experimentally injured menisci of 75 New Zealand white rabbits. Localised neovascularisation occurred in 52% of the angiogenin-treated animals, and in 9% of the controls. Neovascularisation induced by angiogenin may enhance healing of injuries within the poorly vascularised meniscal fibrocartilage, and improve the results of meniscal repair.

Long-term results of total joint arthroplasty in nonambulatory patients.

The authors conducted a long-term follow-up study of 27 patients, all confined to a bed or wheelchair for at least 6 months, who had total joint arthroplasty to relieve rest pain, correct deformity, and enable independent ambulation. The average duration of nonambulatory status before operation was 3 years (mean, 1 1/2 years), with the longest being 15 years. The patients required an average 3-month hospital stay and an average of three major total joint arthroplasties in the lower extremities. All of the patients were ambulatory at the time of discharge but required some sort of aid. After 1 year, 20 patients (74%) were able to launch independently; 9 (33%) could ambulate without aids; and 14 (52%) could ambulate with aids. At follow-up evaluation 3-12.8 years (average, 6.5 years) after operation, nine patients (33%) ambulated without aids, five (19%) required a single crutch or cane, and nine (33%) required bilateral crutches or a walker, for a total success rate of 85%, which did not deteriorate with time.

Femoral component loosening in total knee arthroplasty.

From experience with over 1600 condylar-type total knee arthroplasties performed between 1974 and 1981, the authors identified 15 knees in which the femoral component had loosened and shifted into flexion on the end of the femur. This mode of failure was related to inadequate support of the prosthetic posterior condyle, which resulted from inaccurate surgical cuts, poor cementing technique, or deficient bone stock either primary or secondary to persistent rheumatoid synovitis. Newer prosthetic designs that allow for greater range of motion and maximal function will further test the critical posterior condylar bone interface, as a result of which a higher incidence of femoral component loosening with flexion shift may be seen. Femoral component design changes and surgical techniques that sustain the posterior femoral condyle metal-bone interface may thus be necessary. Femoral components with intramedullary stems may be appropriate for high-risk patients.