[Determination of torsion angle after shaft fractures of the lower extremity--clinical relevance and measurement techniques].

In the treatment of femoral and tibial fractures the frontal and sagittal planes are controlled and documented by conventional X-ray films. Computed tomography permits exact measurement of the coronal plane. Between June 1993 and December 1997, 161 computed tomographic measurements of femoral torsion and 55 of tibial torsion after shaft fracture were carried out. The results were analyzed in a clinical study. A CT examination was carried out if the clinical examination aroused suspicion of a difference in torsion. 28.5% of the patients examined with femoral fractures and 23.8% of those with tibial fractures and torsion differences of more than 20 degrees. Between June 1993 and June 1997, 30 corrective derotating osteotomies of the femur and 9 of the tibia were carried out. The average preoperative difference of torsion of the femur was 29 degrees and of the tibia 25 degrees. After the operation the average femur difference was 7 degrees and of the lower leg 6.5 degrees, which are inside normal physiological limits. The osteotomies were carried out in the metaphysis near the fracture. Additional corrections in other planes were necessary on the femur in 27% and on the lower leg in 46%. With the aim of avoiding torsion differences, or at least to recognize them at an early stage, CT measurements of torsion after osteosythetic treatment of fresh unilateral femur-shaft fractures were carried out in 49 patients between October 1996 and December 1997. The torsion measurements during the operations had to be carried out clinically. No sufficiently exact method of measurement is available in the operating room. Three patients with increased differences of 28 degrees, 26 degrees or 19 degrees had their osteosyntheses corrected. The measurements after correction were inside the normal spread.