Ohmori Takaaki, Kabata Tamon, Kajino Yoshitomo, Taga Tadashi, Hasegawa Kazuhiro, Inoue Daisuke, Yamamoto Takashi, Takagi Tomoharu, Yoshitani Junya, Ueno Takuro, Tsuchiya Hiroyuki
Department of Orthopaedic Surgery, Graduate School of Medical Science, Kanazawa University, Takaramachi13-1, Kanazawa, Ishikawa, Japan.
Int Orthop. 2018 May;42(5):1021-1028. doi: 10.1007/s00264-017-3653-5. Epub 2017 Oct 9.
We investigated the various impingement angles (including both bony and prosthetic impingement) and impingement types that can occur after THA, even when the same combined anteversion parameter is used. We also investigated the relationship between impingement angle and acetabular morphology or femoral anteversion.
We evaluated 83 patients with no hip arthritis. We divided them into six groups according to acetabular CE angle (≤15°, >15-≤25°, and >25°) and femoral anteversion (≤20° and >20°). Using three-dimensional templating software, we changed stem and cup anteversion to satisfy a combined anteversion (CA) of 50° in each hip (stem anteversion + cup anteversion = 50°) and investigated the resulting impingement angles.
Even with the same CA, differences in impingement angle occurred: 18.3° ± 7.2° with flexion, 30.2° ± 9.7° with internal rotation at 90° flexion, 20.2° ± 12.5° with extension, and 26.2° ± 7.8° with external rotation. As stem anteversion increased, the impingement type changed from prosthetic impingement to bony impingement in flexion and internal rotation and from bony impingement to prosthetic impingement in extension and external rotation. The flexion angle and internal rotation angle at 90° flexion increased (p < 0.016) as CE angle decreased. There were no significant differences between high and low femoral anteversion.
Combined anteversion theory should be used with care because of large differences in impingement angles. A stem anteversion of 30° and cup anteversion of 20° appear to be ideal for obtaining a larger impingement angle under this condition.
我们研究了全髋关节置换术（THA）后可能出现的各种撞击角度（包括骨撞击和假体撞击）及撞击类型，即便使用相同的联合前倾角参数。我们还研究了撞击角度与髋臼形态或股骨前倾角之间的关系。
我们评估了83例无髋关节炎的患者。根据髋臼CE角（≤15°、>15°至≤25°、>25°）和股骨前倾角（≤20°和>20°）将他们分为六组。使用三维模板软件，我们改变股骨柄和髋臼杯的前倾角，以使每个髋关节的联合前倾角（CA）达到50°（股骨柄前倾角 + 髋臼杯前倾角 = 50°），并研究由此产生的撞击角度。
即便CA相同，撞击角度仍存在差异：屈曲时为18.3°±7.2°，90°屈曲时内旋为30.2°±9.7°，伸展时为20.2°±12.5°，外旋时为26.2°±7.8°。随着股骨柄前倾角增加，屈曲和内旋时的撞击类型从假体撞击转变为骨撞击，伸展和外旋时从骨撞击转变为假体撞击。随着CE角减小，90°屈曲时的屈曲角度和内旋角度增大（p < 0.016）。股骨前倾角高低之间无显著差异。
由于撞击角度存在较大差异，联合前倾角理论应谨慎使用。在这种情况下，股骨柄前倾角30°和髋臼杯前倾角20°似乎是获得更大撞击角度的理想选择。
