ABSTRACT
We proposed a method of regional assessment in patients with rheumatoid arthritis. The utility of this method was demonstrated by assessing drug efficacy in patients who received infliximab (n = 31) or tocilizumab (n = 6). Joints were divided into four regions: upper/large, upper/small, lower/large, and lower/small. The total joint index was calculated as follows: the sum of tender and swollen joint counts divided by the number of evaluable joints in each region. At the baseline, the total joint index of the upper/small region was the lowest and that of the lower/large region was the highest compared with other regions. The change in the total joint index from the baseline to the 30-week point (Δ) did not differ among the four regions. There were significant close relations of Δ between the upper/small and the upper/large region and between the lower/small and the lower/large region. This method allows us to focus on a specific region and to compare and contrast among them.
Subject(s)
Antibodies, Monoclonal, Humanized/therapeutic use , Antibodies, Monoclonal/therapeutic use , Antirheumatic Agents/therapeutic use , Arthritis, Rheumatoid/diagnosis , Arthritis, Rheumatoid/drug therapy , Joints/drug effects , Joints/pathology , Outcome Assessment, Health Care , Arthritis, Rheumatoid/pathology , Arthritis, Rheumatoid/physiopathology , Humans , Infliximab , Japan , Joints/physiopathology , Predictive Value of Tests , Retrospective Studies , Severity of Illness Index , Treatment OutcomeABSTRACT
OBJECTIVE AND DESIGN: The purpose of this study was to evaluate whether the stress and displacement change with differing shapes of the tibial component in total knee arthroplasty. BACKGROUND: There are few reports on tibial tray mechanics with and without a posterior concave slot, using three-dimensional finite element analysis. METHODS: By considering two different shapes for the tibial component, we analyzed the von Mises stresses and displacements at the component/bone interface and surrounding bone using a three-dimensional finite element model. RESULTS: There was no difference between the two designs in regards to the von Mises stress fields or displacements. The displacement of the tibial tray with a posterior concave slot was less than that of the tray without one in some of the loading configurations. The posterior concave slot appears to reduce the micromotion of the tibial component. DISCUSSION AND CONCLUSION: Overall, this finite element analysis showed little difference between the two different types of tibial base plates used with both posterior cruciate ligament retention and substitution. The results of this finite element model analysis do not support the use of tibial base plates without a posterior cut-out slot.
