Fracture of the tibial tray following PCA knee replacement

We report two cases in which fracture of the tibial metal tray was thought to be due to improper design of the tray and heavy polyethylene wear. The bone beneath the fractured portion of the tray was deficient and had been replaced by granulomatous fibrous tissue including numerous polyethylene wear particles and foreign-body giant cells. Osteolysis occurred as a tissue reaction to these particles.     

Ultrastructural analysis of platelet-like particles from a human megakaryocytic leukemia cell line (CMK 11-5).

Ultrastructural observations were performed to further characterize the human megakaryocytic leukemia cell line, CMK, and its subclone, CMK11-5. We found that particles derived from CMK11-5 cells had cytoplasmic projections and no nucleus, and that some particles contained alpha granules. Incubation with ADP induced fibrinogen receptors on the surface of these particles. Furthermore, the particles had glycoprotein Ib antigen on their surfaces, and attached nonreversibly to rabbit aortic subendothelium, showing associated morphological changes similar to those observed in normal platelets. CMK and CMK11-5 are the first megakaryocytic cell lines that have been found to release particles that have some of the same functions as normal platelets. In particular, CMK11-5 seems to be a useful model for studying megakaryocyte function.     

Xanthogranulomatous Cholecystitis Masquerading as Gallbladder Carcinoma

We herein present a case of xanthogranulomatous cholecystitis which involved hoth the liver and transverse colon, clinically mimicking gallbladder carcinoma. Such cases may sometimes he judged inoperable due to extensive extra-gallbladder invasion, and thus it is necessary for physicians to take this lesion into consideration when making a diagnosis. An intraoperative biopsy is necessary, therefore, even when the feaures seem to clearly indicate inoperable carcinoma.     

In vivo measurement of apparent trabecular bone structure of the radius in women with low bone density discriminates patients with recent wrist fracture from those without fracture.

The purpose of this cross-sectional case-control study was to determine whether indices of bone structure at the 4% site of the radius discriminate women who have sustained a recent low-energy fracture of the contralateral distal radius (n = 21) from women with similar bone density and no history of fracture (n = 21). Images of the distal forearm were acquired using peripheral quantitative computed tomography (pQCT) and were analyzed using in-house-developed software to determine indices of trabecular bone structure (average hole size [H(A)], maximum hole size, and connectivity index). The same images were analyzed using commercial software to determine bone density, mass, geometry, and torsional strength. The fracture group had significantly larger H(A) (p = 0.03). No other bone variable differed between groups. Individual H(A) values were compared to the mean value for young adult women (n = 42). The odds ratio (95% confidence interval) associated with an H(A) >2 SDs above the young adult mean was 5.4 (1.2-24.3). Thus, estimation of in vivo trabecular bone porosity by measuring the average diameter of the pQCT-imaged marrow spaces in the ultradistal radius identifies individuals with low bone mass most at risk for osteoporotic fracture.