Does valgus femoral osteotomy improve femoral head roundness in severe Legg-Calvé-Perthes disease? - Kim HT; Gu JK; Bae SH; Jang JH; Lee JS; Kim, Hui Taek; Gu, Ja Kyung; Bae, Sung Ho; Jang, Jae Hoon; Lee, Jong Seo (Clinical Orthopaedics & Related Research®, 2013)