FEASIBILITY OF PHOTOGRAMMETRY AS A CLINICAL RESEARCH TOOL

The measurement of small or inaccessible three-dimensional displacements in the musculoskeletal system is often desirable. Photogrammetry is not only more accurate than current methods, but less restrictive to the subject. Apart from attached photographic targets, there is no wiring or other encumbrances to inhibit movements including those of ambulation. The feasibility of photogrammetry was evaluated during a study of tibial fracture patients. The relative translational and rotational displacements of the tibial fracture fragments were quantitated by photogrammetrically following the motions of a skeletal pin reference system inserted above and below the fracture line. Using a Zeiss SMK-40 stereocamera at 2. 5m, translations and rotations were discernible down to 1. 0-1. 5mm and 0. 4-1. 5 degree respectively, on moving patients. The practical value of this method, as a clinical research tool, will depend upon the extent to which the data processing and reduction procedures can be simplified.