Diagnostik der Posttraumatischen Beindeformitäten

Abstract

In the clinical examination it is possible to determine the absolute difference in leg length by the board method or, more quickly, the PALM method (accurate to 1.5 cm either way). Determination of the difference in leg length with a measuring tape is even less accurate. The use of radiological methods to determine the relative leg length is considerably more exact. Orthoroentgenography and CT are characterized by accuracy of 3 mm and reproducibility of 2 mm either way. In these cases, then, deviations of up to 5 mm in an individual measurement are possible. The accuracy of navigation-assisted ultrasonographic measurement (2.5 D sonography) is in the same order of magnitude. Even when teleroentgenography is carried out in a standardized manner the accuracy and reproducibility of measurments of the axis of the leg is 3°. The anatomic leg axis should not be determined on long knee joint exposures, because this method is even less accurate. Torsion angle differences cannot be diagnosed clinically with sufficient accuracy except in the lower leg (95% error <15°). In the region of the upper leg there is only a limited correlation between the range of movement in the hip joint and the angle of antetorsion. The gold standard for the measurement of angles of torsion is CT (accuracy ±3° and ±1°, reproducibility ±4° and ±7°, for the upper and lower leg, respectively). The difference between the torsion angles in the two legs can be ascertained by means of the image transformer during the course of surgery (accuracy ±2°, reproducibility ±3°). 2.5-D ultrasonography is also suitable for precise determination of torsion in the upper and lower leg. Because it involves no radiation burden this is the method of choice for determination of the entire geometry of the leg. © Springer Medizin Verlag 2006.