[Rachitic knock knees in children].
Knee malpositions, for example valgus or varus deformations or flexion contractures, were often cited in the historical literature. In earlier times, clinical pictures such as rickets were often the reason for this kind of deformity. A causal therapy did not exist until the twentieth century. In most cases of rickets, genu valgum was reported as the typical knee deformation. The differential diagnosis for genu valgum caused by rickets was genu valgum traumaticum, paralyticum, and inflammatorium. The most important reports on the pathogenesis of valgus deformation can be found in publications by Hueter and von Mikulicz. The causal therapy of rickets was introduced at the beginning of the twentieth century.Vitamin therapy and UV phototherapy were developed during this period. Using these therapies, rickets decreased dramatically. Kurt Huldschinsky, a pediatrician from Berlin,was one of the main inventors of UV phototherapy in Germany. At the end of the nineteenth century, the operative correction of knee deformities increased while conservative treatment continued to be applied. Plaster casts,orthoses, and osteoclast therapy were the main noninvasive therapeutic possibilities. Positive aspects of the conservative techniques were mostly the good results and easy, timesaving technique compared with the operative treatment. The operative therapy increased with the knowledge of antisepsis and asepsis as well as advances in anesthetic procedures. Operative treatment modalities, for example tibial and femoral osteotomies, were more precise, but connected with multiple complications and greater time expenditure. Sufficient vitamin prophylaxis rendered knee deformations caused by rickets a rarity.