Department of Orthopedics and Traumatology, Cantonal Hospital Winterthur, Brauerstrasse 15, 8409, Winterthur, Switzerland.
Department of Pediatric Surgery, University Children's Hospital of Basel, Basel, Switzerland.
Knee Surg Sports Traumatol Arthrosc. 2022 Feb;30(2):447-455. doi: 10.1007/s00167-020-06150-x. Epub 2020 Jul 16.
Efforts in total knee arthroplasty are made to improve accuracy for a correct leg axis and reduce component malpositioning using patient-specific instruments. It was hypothesized that use of patient-specific instruments (vs. computer-navigated and conventional techniques) will reduce the number of outliers. Our second hypothesis was that single-use instrumentation will lead to the same accuracy compared to patient-specific instruments made of metal.
708 primary total knee arthroplasties between 2014 and 2018 using computer tomography (CT)-based patient-specific cutting block technique and a preoperative planning protocol were retrospectively reviewed. Preoperative data [hip-knee-angle (HKA), lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), tibial slope, femoral component flexion] was compared to postoperative performed standard radiological follow-up X-rays. Differences of > 3° between measurements were defined as outliers.
Overall 500 prostheses using standard instrumentation and 208 prostheses using single-use instruments were implanted. Preoperative HKA axes (- 1.2°; p < 0.001), femoral component flexion (Δ 0.8°, p < 0.001), LDFA (Δ - 1.5°, p < 0.001), MPTA (Δ - 0.5°, p < 0.001) and tibial posterior slopes (Δ 0.5°, p < 0.001), respectively, were different from postoperative axes. More outliers occurred using standard (vs. single-use) instruments (p < 0.001) regarding postoperative HKA (ranges of standard- vs. single-use: instruments: HKA 178.0°-180.5° vs. 178.0°-180.5°, femoral component flexion 0.0°-6.0° vs. 0.0°-4.5°, LDFA 90.0°-91.0° vs. 90.0°-90.0°, MPTA 90.0°-90.0° vs. 90.0°-90.0°, tibial posterior slope - 10° to 10° vs. - 1° to 10°). No differences were seen for other angles measured. Comparing both systems, total number of outliers was higher using standard (8%) vs. single-use instruments (4.3%).
This study shows a high accuracy of CT-based patient-specific instrumentation concerning postoperative achieved knee angles and mechanical leg axes. Single-use instruments showed a similar accuracy.
III.
在全膝关节置换术中，人们努力提高准确的下肢轴线和减少使用特定于患者的器械的部件错位。我们假设使用特定于患者的器械（与计算机导航和常规技术相比）将减少离群值的数量。我们的第二个假设是，与金属制成的特定于患者的器械相比，一次性使用器械将具有相同的准确性。
回顾性分析了 2014 年至 2018 年间使用基于计算机断层扫描（CT）的特定于患者的切割块技术和术前规划方案进行的 708 例原发性全膝关节置换术。比较了术前数据[髋膝角（HKA）、外侧远端股骨角（LDFA）、内侧近端胫骨角（MPTA）、胫骨倾斜度、股骨组件弯曲]与术后进行的标准影像学随访 X 射线。测量值之间的差异> 3°被定义为离群值。
总共植入了 500 例使用标准器械的假体和 208 例使用一次性器械的假体。术前 HKA 轴（-1.2°；p < 0.001）、股骨组件弯曲（Δ0.8°，p < 0.001）、LDFA（Δ-1.5°，p < 0.001）、MPTA（Δ-0.5°，p < 0.001）和胫骨后斜率（Δ0.5°，p < 0.001）分别与术后轴不同。与使用标准（与一次性）器械相比，术后 HKA 出现更多的离群值（标准-与一次性器械：HKA 178.0°-180.5°与 178.0°-180.5°，股骨组件弯曲 0.0°-6.0°与 0.0°-4.5°，LDFA 90.0°-91.0°与 90.0°-90.0°，MPTA 90.0°-90.0°与 90.0°-90.0°，胫骨后斜率-10°至 10°与-1°至 10°）。测量的其他角度未见差异。比较两种系统，标准（8%）比一次性器械（4.3%）的离群值总数更高。
本研究表明，基于 CT 的特定于患者的器械在术后获得的膝关节角度和机械下肢轴方面具有较高的准确性。一次性使用器械具有相似的准确性。
III。
