Analysis of Femoral cortical Indices in Cementless Femoral Stem

Lee, Kwang Suk; Park, Sang Won; Han, Seung Beom

Abstract

Preperative radiologic indices, such as cortical index of Engh, morphological cortical index of Sportono and Romagnoli, canal flare index of Noble, and their relationship to the postoperative canal filling, femoral stem fitness, stability and clinical result at last follow up were analyzed in 111 hips of 96 patients treated with bipolar or total hip arthroplasty at the Department of Chthopedic Surgery, Korea University Hospital, between January 1985 and May 1993. The results obtained were as follows: 1. The cortical index had no correlations with age, metaphyseal filling and clinical result but isthmic filling was proportional to the cortical index. In femoral stem fitness and stability, most cases of press fit and optimal stability were obtained in group 3 and 4 that have thick cortex. 2. The morphological cortical index had no correlation with age, canal filling and clinical results. But it was proportional to the postoperative femoral stem fitness and stability. 3. The canal flare index had no correlation with age. The metaphyseal filling was increased in the stove piped canal group(less than 3.0 canal flare index), but isthmic filling was increased in normal canal group(3.0-4.7 canal flare index). The most cases of press fit and optimal stability were obtained in normal canal group. More satisfactory clinical results were obtained in nomal canal group. Above results suggest that straight type of cementless femoral component could get better press fit fixation, postoperative stability and more satisfactory clinical results in the cases of cortical index larger than 2.0, mophological cortical index larger than 2.7 and canal flare index larger than 4.0 but metaphyseal filling is unsatisfactor.