Modular Necks Improve the Range of Hip Motion in Cases with Excessively Anteverted or Retroverted Femurs in THA

• DOI: 10.1007/s11999-010-1385-6
• Publication Date: 2010-05-14T13:54:31Z
• Authors: Akinobu Matsushita; Yasuharu Nakashima; Masanori Fujii; Taishi Sato; Yukihide Iwamoto
• Keywords: External rotation

Anteversion of an acetabular component often is difficult to ascertain in patients with THA whom excessively anteverted or retroverted femurs may result limited ROM risk dislocation. Restriction motion, however, determined by the combination version both components.We therefore combined anteversion values that provide adequate ROM. We varied differing implantations and femoral modular necks.ROM was tested changing cup after setting 20° 60° retroversion. The angle neck adjusted 11 increments 5° each. Range internal rotation (IR) at 90° flexion, external (ER) 0° extension, flexion (Flex) were measured when any impingement occurred before defined a required as having 40° IR, 30° ER, 110° Flex.At anteversion, ER less than 10° even set retroversion because posterior impingement. When 25° used, improved greater 30°. At retroversion, IR 31° opened 35° anteversion. 34° necks, respectively.In cases excessive could not be achieved simply components. adjustment versions using necks allowed additional improvement