[Unilateral stepwise lengthening osteotomy of the femur].

Intraindividual length differences up to 1.2 cm in femora, up to 1.0 cm in tibiae and up to 1.4 cm in whole leg length can be regarded as physiological. Length differences in childhood are frequently compensated for by functional adaptation in the chain of adjacent limbs. In adults, however, that adaptability is diminished and correction osteotomy after post-traumatic shortening may therefore be indicated more generously dependent on local and general criteria of operability. A conscientious analysis of bone geometry by clinical means, radiology and computed tomography is mandatory for the indication and planning of any correction osteotomy. Intraindividual leg length differences of more than 4 cm are preferentially treated by continuous callus distraction techniques. Shortening by less than 4 cm, however, is suitable for a one-stage stepwise prolongation osteotomy in the metaphysis of the femur, i.e. in the subtrochanteric or supracondylar region. These osteotomies are than stabilized by long condylar plates; the bony defects are filled up by auto- or allogenous corticospongeous bone. Simple modifications of the stepwise prolongation osteotomy permit additional corrections of torsional deviations up to 20 degrees or of axial deviations in the frontal or sagittal plane up to 5 degrees. The results of 24 one-stage stepwise prolongation osteotomies of the subtrochanteric and supracondylar femur after congenital or post-traumatic shortening are presented as well as the reason and respective therapies for three important complications.