Department of Orthopedic Surgery, Mayo Clinic, 200 First Street S.W, Rochester, MN, 55905, USA.
Arch Orthop Trauma Surg. 2024 Sep;144(9):4125-4132. doi: 10.1007/s00402-024-05336-z. Epub 2024 Jun 14.
Achieving adequate alignment has traditionally been an important goal in total knee arthroplasty to achieve long-term implant survival. While accelerometer-based hand-held navigation systems (ABN) has been introduced as a way to achieve alignment, there is a limited body of evidence on its accuracy, especially in patients under 65 years with differing etiologies for knee arthritis. This study aimed to assess the precision of a specific ABN system in restoring the mechanical axis and report surgical variables and complications, with particular attention to younger patients.
We conducted a retrospective review of 310 primary TKA performed with ABN from May 2016 to February 2021. The mean patient age was 67.4 (SD 8.9) years, with 43% under 65 years and mean body mass index of 33.2 (SD 6.8). The average surgical time was 96.8 min (57-171) and the average follow-up was 3.3 years (1.9-6.7). Data regarding length of stay, pain, range of motion (ROM), complications, and reinterventions were collected from the institutional joint arthroplasty registry and the medical records. Preoperative mechanical axis measurements and postoperative radiological data, including mechanical axis, component alignment and mechanical alignment outliers were analyzed.
The mean preoperative mechanical axis was 175.4° (SD 7.6), with 248 knees (80%) in preoperative varus. The mean postoperative mechanical axis was 179.5° (SD 1.96) with 98% of knees falling within ± 3° of the neutral mechanical axis. Only 6 knees (2 varus, 4 valgus) fell outside the ± 3° range. And 3 knees (1 varus, 2 valgus) fell outside the ± 5° range. In the sagittal plane, 296 knees (95.5%) knees were within ± 3° of goal of 3 degrees of femoral flexion and 302 (97.4%) knees were within ± 2° of goal 1° of slope for tibial component. Far outliers (alignment outside ± 5° of targeted position) were found in 3 knees. Factors such as posttraumatic arthrosis, previous surgery, presence of retained hardware, and age below 65 years were not associated with increase in alignment outliers and far outliers. No complications related to the navigation system were observed. There were 22 complications and 20 reoperations, including 2 revisions for periprosthetic joint infection and 1 revision for flexion instability. Patients that required knee manipulation achieved an ultimate flexion of 110° (SD 14.1).
The ABN system proved to be user-friendly and accurate in reducing alignment outliers in both coronal and sagittal planes in all patient populations. It offers a straightforward navigation solution while preserving surgeon autonomy and the use of traditional surgical tools. These findings advocate for the integration of this navigation system as a valuable tool to enhance the precision of TKA surgery in all patient groups.
在全膝关节置换术中，实现充分的对线一直是一个重要的目标，以达到长期植入物的存活率。虽然基于加速度计的手持导航系统 (ABN) 已被引入作为实现对线的一种方法，但关于其准确性的证据有限，尤其是在患有不同病因膝关节关节炎且年龄在 65 岁以下的患者中。本研究旨在评估特定 ABN 系统在恢复机械轴方面的精度，并报告手术变量和并发症，特别关注年轻患者。
我们对 2016 年 5 月至 2021 年 2 月期间使用 ABN 进行的 310 例初次 TKA 进行了回顾性分析。患者平均年龄为 67.4（SD 8.9）岁，其中 43%年龄在 65 岁以下，平均 BMI 为 33.2（SD 6.8）。平均手术时间为 96.8 分钟（57-171），平均随访时间为 3.3 年（1.9-6.7）。从机构关节置换登记处和病历中收集了关于住院时间、疼痛、活动范围 (ROM)、并发症和再次手术的数据。分析了术前机械轴测量值和术后影像学数据，包括机械轴、组件对线和机械对线离群值。
术前机械轴平均为 175.4°（SD 7.6），248 膝（80%）术前呈内翻。术后机械轴平均为 179.5°（SD 1.96），98%的膝关节在中立机械轴的±3°范围内。只有 6 个膝关节（2 个内翻，4 个外翻）超出了±3°的范围。有 3 个膝关节（1 个内翻，2 个外翻）超出了±5°的范围。在矢状面，296 个膝关节（95.5%）的膝关节在 3 度股骨屈曲目标的±3°范围内，302 个膝关节（97.4%）的膝关节在胫骨组件 1°斜率目标的±2°范围内。在 3 个膝关节中发现远离群值（对线超出目标位置±5°）。创伤后关节炎、既往手术、保留内固定物以及年龄低于 65 岁等因素与对线离群值和远离群值的增加无关。未观察到与导航系统相关的并发症。共有 22 例并发症和 20 例再次手术，包括 2 例假体周围关节感染翻修和 1 例屈曲不稳定翻修。需要膝关节手法复位的患者最终获得 110°（SD 14.1）的屈曲度。
ABN 系统在所有患者群体中均证明在冠状面和矢状面减少对线离群值方面既易用又准确。它提供了一种简单的导航解决方案，同时保留了外科医生的自主性和传统手术工具的使用。这些发现支持将该导航系统作为一种有价值的工具整合到所有患者群体中，以提高 TKA 手术的精度。
