An antithrombin III mutation database was collated and published in L99L by a group of investigators working on the molecular basis of antithrombin III deficiency (1). Soon after, under the auspices of the ISTH SSC, an Antithrombin III Working Party was formed of those involved in the preparation of the database, with the instruction to report to the "Thrombin and its Inhibitors" SSC on the developments in this and related areas. This document is one outcome of the work of the Antithrombin III Working Party and is a partial report of the deliberations of the "Thrombin and its Inhibitors" SSC Meeting held in Munich, July 1992. Other items discussed at this meeting included the nomenclature of the plasma coagulation inhibitors. Three alternative names were considered for this inhibitor, antithrombin III, antithrombin and thrombin inhibitor I. No unanimous view emerged regarding the name, other than the rejection of the term thrombin inhibitor I. For this report, the historical name antithrombin III will be used, despite the preference for anti. thrombin by the majority of the authors of this database. This is in deference to the journal, Thrombosis and Haemostasis, pending any final decision of the SSC regarding nomenclature. The intention behind the production and updating of the antithrombin III database has been to provide a readily accessible and up-to-date source of known mutations of antithrombin III. The complex effects of some mutations on structure/function relationships of the protein can only be indicated. For more information on this and on possible mechanisms involved in gene mutation (see below for brief consideration of mutations involving CpG dinucleotides), the reader is referred to the original papers and to several reviews in this area (2-6).

An in vitro simulator was developed to reproduce the kinematics and kinetics of stance phase gait on cadaver foot specimens. Ground reaction force was applied by a tilting angle- and force-controlled translation stage upon which a pressure measuring platform was mounted; tibial rotation was reproduced by a servomotor. Force was applied to nine tendons of the foot flexor and extensor muscle groups, and three-dimensional hind- and forefoot motion was measured. The model was verified based on in vivo kinematic and kinetic measurements. It was found to be in good general agreement with some exceptions which include a slightly more lateral gait line.

Classical marker-based roentgen stereophotogrammetric analysis (RSA) is an accurate method of measuring in vivo implant migration. A disadvantage of the method is the necessity of placing tantalum markers on the implant, which constitutes additional manufacturing and certification effort. Model-based RSA (MBRSA) is a method by which pose-estimation of geometric surface-models of the implant is used to detect implant migration. The placement of prosthesis markers is thus no longer necessary. The accuracy of the pose-estimation algorithms used depends on the geometry of the prosthesis as well as the accuracy of the surface models used. The goal of this study was thus to evaluate the experimental accuracy and precision of the MBRSA method for four different, but typical prosthesis geometries, that are commonly implanted. Is there a relationship existing between the accuracy of MBRSA and prosthesis geometries? Four different prosthesis geometries were investigated: one femoral and one tibial total knee arthroplasty (TKA) component and two different femoral stem total hip arthroplasty (THA) components. An experimental phantom model was used to simulate two different implant migration protocols, whereby the implant was moved relative to the surrounding bone (relative prosthesis-bone motion (RM)), or, similar to the double-repeated measures performed to assess accuracy clinically, both the prosthesis and the surrounding bone model (zero relative prosthesis-bone motion (ZRM)) were moved. Motions were performed about three translational and three rotational axes, respectively. The maximum 95% confidence interval (CI) for MBRSA of all four prosthesis investigated was better than -0.034 to 0.107 mm for in-plane and -0.217 to 0.069 mm for out-of-plane translation, and from -0.038 deg to 0.162 deg for in-plane and from -1.316 deg to 0.071 deg for out-of-plane rotation, with no clear differences between the ZRM and RM protocols observed. Accuracy in translation was similar between TKA and THA components, whereas rotational accuracy about the long axis of the hip stem THA components was worse than the TKA components. The data suggest that accuracy and precision of MBRSA seem to be equivalent to the classical marker-based RSA method, at least for the nonsymmetric implant geometries investigated in this study. The model-based method thus allows the accurate measurement of implant migration without requiring prosthesis markers, and thus presents new opportunities for measuring implant migration where financial or geometric considerations of marker placement have thus far been prohibitive factors.