Pongkunakorn Anuwat, Chatmaitri Swist, Diewwattanawiwat Kittipong
Department of Orthopaedic Surgery, Lampang Hospital and Medical Educational Center, Lampang, Thailand.
J Orthop Surg (Hong Kong). 2019 Jan-Apr;27(1):2309499019825578. doi: 10.1177/2309499019825578.
The position of the acetabular cup is important to the outcome of total hip athroplasty (THA). We devised an instrument that uses the level indicator application of smartphone together with a mechanical alignment guide to improve the precision of cup placement. This study aims to determine the percentage of acetabular cups positioned in the Lewinnek safe zone comparing between the conventional technique (using a mechanical alignment guide alone) and the smartphone technique (using a mechanical alignment guide combined with the devised instrument and smartphone).
A historical controlled trial was conducted among 82 patients who underwent primary THAs through a posterolateral approach. In the conventional group, 41 cups were placed during January 2013 and December 2014, whereas 41 cups in the smartphone group were placed during January 2015 and March 2016. Inclination and anteversion angles were measured in standardized pelvic radiographs. The cup orientation was compared between groups.
The inclination angle in the smartphone group was significantly lower than in the conventional group (40.9° (SD 3.8) vs. 46.3° (SD 6.7), p < 0.001), but the anteversion angle was higher (19.6° (SD 4.4) vs. 16.5° (SD 6.1), p = 0.010). The smartphone group had more cups positioned in the Lewinnek safe zone (90.2% vs. 56.1%, p = 0.001) and longer operative times (136 (SD 27) vs. 119 (SD 23) min, p = 0.011). No significant difference was found for blood loss ( p== 0.384) or dislocation rate ( p = 0.494).
Using the computerized function of smartphone could improve the precision of cup positioning. Most cups were placed within a narrow margin inside the Lewinnek safe zone.
髋臼杯的位置对全髋关节置换术（THA）的疗效至关重要。我们设计了一种仪器，它将智能手机的水平指示器应用与机械对准导向器相结合，以提高髋臼杯放置的精度。本研究旨在比较传统技术（仅使用机械对准导向器）和智能手机技术（使用机械对准导向器与设计的仪器及智能手机相结合）下，位于Lewinnek安全区内的髋臼杯的百分比。
对82例行后外侧入路初次全髋关节置换术的患者进行了一项历史对照试验。传统组在2013年1月至2014年12月期间植入41个髋臼杯，而智能手机组在2015年1月至2016年3月期间植入41个髋臼杯。在标准化骨盆X线片上测量倾斜角和前倾角。比较两组之间的髋臼杯方向。
智能手机组的倾斜角显著低于传统组（40.9°（标准差3.8）对46.3°（标准差6.7），p<0.001），但前倾角更高（19.6°（标准差4.4）对16.5°（标准差6.1），p = 0.010）。智能手机组有更多的髋臼杯位于Lewinnek安全区内（90.2%对56.1%，p = 0.001），且手术时间更长（136（标准差27）对119（标准差23）分钟，p = 0.011）。在失血量（p = 0.384）或脱位率（p = 0.494）方面未发现显著差异。
使用智能手机的计算机功能可提高髋臼杯定位的精度。大多数髋臼杯放置在Lewinnek安全区内的狭窄范围内。
