Purpose : THA have been aggressively performed for elderly patients in order to improve ADL and QOL. We have performed metal-on-metal THA in this setting.
Methods : The subjects comprised 28 patients, in whom 30 hips were treated. There were 5 hips in 5 males, and 25 hips in 23 females, all of whom were over 75 years old and underwent metal-on-metal THA at our hospital from July, 2010. The average patient age was 79.0 (75 to 89) years, and the primary diseases were OA in 27 hips, ION in 2, and RA in one. We observed the preoperative pelvic inclination angle measured in APP in the spine and standing position, intraoperative blood loss, operation time, complications, and the cup setting angle after surgery.
Results : The average preoperative pelvic tilting angle was -2.1 degrees in the supine position, and - 4.2 degrees in the standing position. In both positions, 11 hips were forward tilting and 19 were backward tilting. Mean intraoperative blood loss was 224 (10 to 1000)g, and the mean operation time was 78.2 (45 to 125) min. There were no complications such as intraoperative fracture, postoperative dislocation, infection, or loosening. The postoperative average cup setting angle was 40.0 (28 to 57) degrees in inclination, and 12.5 (-12 to 35) degrees in version.
Discussion and Conclusion : It is known that the pelvis shows retroversion in the elderly, and therefore it is important for orthopaedic surgeons to consider postoperative dislocation when treating such patients. Metal-on-metal has the advantage of low wear, a wide range of motion, and high resistance to dislocation. Therefore it is considered a good technique for elderly patients with advanced backward tilting.
