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  • G Selvik
  • 1989
I have developed a roentgen stereophotogrammetric method for determination of positions of radiopaque markers in an object. The space coordinates are determined in a laboratory coordinate system, which is defined by markers in a test "cage". The markers in the test cage function as calibration points, and are roentgenographed on the same film(s) as the(More)
Soon after Roentgen's discovery, the 'new' rays were used to produce stereoscopic images or used for spatial reconstruction of positions of foreign bodies. However, no systematic use of roentgen stereo measurements seems to have occurred until the 1970's, although many attempts have been made before. Since 1972, a system for roentgen stereophotogrammetry(More)
Twenty-five patients (21 females and 4 males) with sacroiliac joint disorders were studied with roentgen stereophotogrammetry in physiologic positions as well as in the extreme of physiologic positions. There was a constant pattern of motion with different load, especially around the transverse axis. The rotations were small and in mean between position 2.5(More)
Using roentgen stereophotogrammetry we have recorded the three-dimensional movements of the knee during an anteroposterior laxity test in 36 patients with torn anterior cruciate ligaments and in three cadaver knees. At 30 degrees of knee flexion and before loads were applied the tibia occupied a more laterally rotated position if the anterior cruciate(More)
In 10 patients with an old injury of the anterior cruciate ligament, the three-dimensional movements of the knee joint were studied when the patients flexed their knees. Tibial motions were recorded using roentgen stereophotogrammetric analysis. Internal rotation and adduction of the tibia were reduced in the injured knees when compared with the intact(More)
Using a roentgen stereophotogrammetric method, the three-dimensional movements in the sacroiliac joints were quantified in 4 patients. To provoke motion of the sacrum, changes between body positions and a test with manual pressure were used. In tests with symmetric forces on the sacrum, it in most cases rotated mainly about a transverse axis and at most(More)
We studied the effect of a metal tray with an intramedullary stem on the micromotion of the tibial component in total knee arthroplasty. Of 32 uncemented Freeman-Samuelson knee arthroplasties performed in London and Gothenburg, nine had a metal backing and stem added to the tibial component. Micromotion of the tibial components, expressed as migration and(More)
An analytical stereophotogrammetric method is introduced to measure the three-dimensional geometry of articular surfaces in vitro. Information of this kind is particularly useful for mathematical joint models and anthropological studies. The method requires no specific equipment, such as a stereocomparator, contrarily to other techniques reported (e.g.(More)
Twenty patients were examined by standard radiography and roentgen stereophotogrammetric analysis (RSA) during a two-year period after total hip arthroplasty. Eleven of the acetabular components migrated cranially and three femoral components migrated distally. This migration was most rapid during the first four months after operation. Our findings support(More)
Micromotion of the tibial component, both as migration over time and as inducible displacement in response to external physiologic forces, was studied in 20 cases of gonarthrosis. The patients had Porous Coated Anatomic primary total knee arthroplasty and were followed for four years. All cases but one were clinically successful. Thirteen components were(More)