A More Accurate Approach to Amyloid Detection and Subtyping: Combining in situ Congo Red Staining and Immunohistochemistry.

Amyloidosis is the result of various, differently approachable diseases. It is vital to subtype the amyloid deposits in order to establish and finally treat the underlying disease properly. Besides the classical staining with Congo red, further procedures like immunohistochemical staining are needed for classification. Here, we present a more accurate approach using Congo red/immunohistochemical double staining easily applicable in routine diagnostics. Modifications of the Congo red staining technique and the immunohistochemical procedures were needed in order to combine both staining procedures on one slide. The evaluation was done using conventional light and fluorescence microscopy. By shortening the staining time for Congo red to 10 s and by modification regarding endogenous peroxidase blockage, accurate results could be obtained for evaluating the Congo red/immunohistochemistry double staining using a fluorescence microscope. Sections of 2 µm instead of 4 µm thickness were superior for evaluation, since they increased staining specificity. The combination of Congo red and immunohistochemistry as in situ double staining on one slide is a feasible approach in the diagnosis of amyloidosis. It allows focusing on the fluorescent Congo red-positive areas when evaluating immunohistochemistry, thus avoiding signing out false-positive results. Additionally, it increases the signal-to-noise ratio of the immunohistochemically stained sections on conventional microscopy.

Long-term survival and radiological results of the Duracon™ total knee arthroplasty.

PURPOSE: The aim of this study was to analyse the long-term (>ten years) survival rate and radiological results of the Duracon TKA. METHODS: Between 1992 and 1999 159 Duracon TKA were implanted at our institution. A Kaplan-Meier survival analysis for the endpoints exchange, addition or removal of any component for any reason, revision due to aseptic loosening and mechanical failure was performed. Radiological long-term (>ten years) follow-up (FU) analysis was performed according to the Knee Society Radiographic Evaluation and Scoring System. RESULTS: Mean age at surgery was 74.3 years, 28% were male, and 89% had primary osteoarthritis as diagnosis. Mean FU for survival analysis was 10.9 years (SD 4.2). A total of 58% of the patients died during follow-up. Three patients (2.1%) were lost to follow-up and five TKA (3.1%) were revised. After ten years the mean survival was 97.7%, 99.4% and 98.3% for the aforementioned endpoints, respectively. Mean radiological FU was 11.8 years (SD 2.3). We found no significant change in alignment of the components or axis over time. Progressive radiolucencies were found in nine TKA (17%), mainly around the tibial component (95%). CONCLUSION: The Duracon TKA showed excellent long-term survival comparable to data from national registers and to other successful designs. Radiological changes found on plain radiographs were scarce after almost 12 years of radiological follow-up indicating good implant stability.