Palit A, King R, Gu Y, Pierrepont J, Hart Z, Elliott M T, Williams M A
Annu Int Conf IEEE Eng Med Biol Soc. 2019 Jul;2019:2127-2131. doi: 10.1109/EMBC.2019.8857861.
Bony impingement (BI) may contribute to restricted hip joint motion, and recurrent dislocation after total hip arthroplasty (THA), and therefore, should be avoided where possible. However, BI risk assessment is generally performed intra-operatively by surgeons, which is partially subjective and qualitative. Therefore, the aim of the study was to develop a method for identifying subject-specific BI, and subsequently, visualising BI area on native bone anatomy to highlight the amount of bone should be resected. Activity definitions and subject-specific bone geometries, constructed from CT scans, with planned implants were used as inputs for the method. For each activity, a conical clearance angle (CCA) was checked between femur and pelvis through simulation. Simultaneously, BI boundary and area were automatically calculated using ray intersection and region growing algorithm respectively. The potential use of the developed method was explained through a case study using an anonymised pre-THA patient data. Two pure (flexion, and extension) and two combined hip joint motions (internal and external rotation at flexion and extension respectively) were considered as activities. BI area were represented in two ways: (a) CCA specific where BI area for each activity with different CCAs was highlighted, (b) activity specific where BI area for all activities with a particular CCA was presented. Result showed that BI area between the femoral and pelvic parts was clearly identified so that the pre-operative surgical plan could be adjusted to minimise impingement. Therefore, this method could potentially be used to examine the effect of different preoperative plans and hip motion on BI, and to guide bony resection during THA surgery.
骨撞击（BI）可能导致髋关节活动受限以及全髋关节置换术（THA）后反复脱位，因此应尽可能避免。然而，BI风险评估通常由外科医生在手术中进行，这部分是主观的和定性的。因此，本研究的目的是开发一种识别个体特异性BI的方法，随后在原始骨解剖结构上可视化BI区域，以突出应切除的骨量。由CT扫描构建的活动定义和带有计划植入物的个体特异性骨几何形状被用作该方法的输入。对于每个活动，通过模拟检查股骨和骨盆之间的圆锥间隙角（CCA）。同时，分别使用射线相交和区域生长算法自动计算BI边界和面积。通过使用匿名的THA术前患者数据的案例研究解释了所开发方法的潜在用途。两种单纯（屈曲和伸展）和两种联合髋关节运动（分别在屈曲和伸展时的内旋和外旋）被视为活动。BI区域以两种方式表示：（a）特定CCA，其中突出显示具有不同CCA的每个活动的BI区域；（b）特定活动，其中呈现具有特定CCA的所有活动的BI区域。结果表明，股骨和骨盆部分之间的BI区域被清晰识别，从而可以调整术前手术计划以最小化撞击。因此，该方法可能用于检查不同术前计划和髋关节运动对BI的影响，并在THA手术期间指导骨切除。
