Richolt J A, Rittmeister M E
Orthopädische Universitätsklinik, Stiftung Friedrichsheim, Frankfurt am Main.
Z Orthop Ihre Grenzgeb. 2006 May-Jun;144(3):305-10. doi: 10.1055/s-2006-933495.
Computer assisted navigation of the acetabular cup in THR requires reliable digitalisation of bony landmarks defining the frontal pelvic plane by user driven palpation. According to the system recommendations the subcutaneous fat should be held aside during epicutaneous digitalization. To improve intraoperative practicability this is often neglected in the symphysis area. In these cases the fat is just compressed and not pushed aside.
In this study soft tissue thickness was assessed by ultrasound and pelvic geometry was measured in 72 patients to quantify potential misinterpretation of cup anteversion triggered by the simplified palpation. As reference we employed data of the same patients that had been acquired by recommended palpation.
Anteversion misinterpretation averaged at 8.2 degrees with extremes from 2 to 24 degrees. There were no correlations between soft tissue thickness or misinterpretation and body weight, height and pelvic size. Anteversion misinterpretation was highly significant worse compared to the reference data.
In 31 % of the patients the anteversion misinterpretation of a navigation system would have been wrong by over 10 degrees and in 81 % over 5 degrees . Therefore the simplified palpation should not be utilized. For epicutaneous digitalization of the bony landmarks it is mandatory to push the subcutaneous fat aside.
在全髋关节置换术中，髋臼杯的计算机辅助导航需要通过用户驱动的触诊对确定骨盆额状面的骨性标志进行可靠的数字化处理。根据系统建议，在经皮数字化过程中应将皮下脂肪拨开。为提高术中实用性，在耻骨联合区域这一点常常被忽视。在这些情况下，脂肪只是被挤压而未被拨开。
在本研究中，通过超声评估72例患者的软组织厚度，并测量骨盆几何形状，以量化简化触诊引发的髋臼前倾潜在误判情况。作为对照，我们采用了同一批患者通过推荐触诊获取的数据。
前倾误判平均为8.2度，极端值为2至24度。软组织厚度或误判与体重、身高及骨盆尺寸之间无相关性。与对照数据相比，前倾误判明显更严重。
在31%的患者中，导航系统的前倾误判会超过10度，81%会超过5度。因此，不应采用简化触诊。对于骨性标志的经皮数字化，必须将皮下脂肪拨开。
