Verification of selected anatomic landmarks used as reference points for universal goniometer positioning during knee joint mobility range measurements.

The study was concerned with verification of the selection of reference points used for knee joint mobility range goniometry. The verification was based on photometric and electrogoniometric methods of femorotibial angle measurements. The material for measurements were three knee joint preparations. The obtained data were subjected to descriptive analysis; photographic documentation of geometric relations between the reference points was also prepared. Considerable divergence of measurement results was observed with respect to the actual knee joint flexion angle, amounting even to 16 degrees. The differences are due to the selection of anatomic landmarks, and depend in particular on the distance of the point to which the goniometer axis is applied from the approximate location of the mechanical joint axis. The corrections of knee joint flexion angle measurements were also estimated on the basis of data obtained from the photographs and the derived mathematical formula.