[The development of the dysplastic hip-joint following intertrochanteric rotating varus-osteotomy (author's transl)].

Evaluation of radiographs of 267 children with 465 intertrochanteric rotating varus osteotomies, carried out between the ages of 15 months and 14 1/2 years. The period of follow-up varied between 2 and 15 1/4 years. 1. The CCD angle on the last radiograph was normal in 77%, once more in values in 16.2%, coxa vara in 7%. 2. The AT angle was about normal only in 58.3% (0-20 degrees); it relapsed in 8.4% (over 35 degrees); in 8.8% a corrected angle did not return after retrorotation, particularly on the left. 3. The Ac angle was normal in 63.3%. 4. The CE angle corresponded to the norm in 59.1%. 5. Good late results (normal angles and shape of head) occur only in 20%. If one omits the AT condition, they rise to 40%. 6. The main causes of return of valgus appear to be: too early operation before the fifth year, mainly when disregarding the dysplastic acetabular roof, insufficient correction of the CCD angle of over 115 degrees, and technical faults. For physiologic weightbearing by the acetabular roof an AT angle of 10 appears necessary. 7. When dysplasia of the acetabular roof is present, the polyaxial correction of the proximal end of femur must be combined with acetabuloplasty or pelvic osteotomy.