University of British Columbia Department of Orthopedics, Vancouver, British Columbia, Canada.
Department of Orthopedics, University of British Columbia, St. Paul's Hospital, Partner, Footbridge Centre for Integrated Foot and Ankle Care, Vancouver, British Columbia, Canada.
Foot Ankle Int. 2019 Oct;40(10):1160-1165. doi: 10.1177/1071100719856548. Epub 2019 Jul 22.
The use of patient-specific instrumentation (PSI) in modern total ankle replacement (TAR) has augmented positioning of the tibial component, eliminating the need for complex jigs. Coronal and sagittal alignment are intuitive with this design and have been studied, but axial rotation has not. The purpose of this study was to assess the relationship between the planned preoperative axial rotation as set by the PSI guide and the rotation determined intraoperatively with non-PSI instrumentation.
This was a prospective cohort study of 22 consecutive cases. The axial rotation angle between the medial gutter and the tibial implant position on the preoperative CT-scan based plan was extracted. At the time of surgery, the medial gutter alignment instrument from the non-PSI instrumentation was inserted and an intraoperative axial photograph obtained to record the angle between the medial gutter and the axial rotation guide pins set by the PSI instrumentation. The 2 measurements were compared and further statistical analysis included Pearson correlation and paired Student test.
The average axial rotation angle between the medial gutter and the implant on the PSI preoperative plan was 5.4 ± 2.9 degrees, whereas the intraoperative photograph from the medial gutter alignment instrument to the pin was 5.9 ±3.8 degrees. This demonstrated a Pearson correlation of = 0.54 and a value of .53. The average difference between the two was -0.46 (95% CI: -2.04, 1.10), meaning that components were either slightly externally rotated or that the fork was aimed internally. Based on this group, 50% (11/22) were within 2 degrees of the target and 77% (17/22) were within 4 degrees of the target.
Patient-specific guides allowed for reproducible rotational tibial component implantation in modern TAR. Further work is needed to better understand the biomechanical effects of the rotational profile and consequences on survivorship.
Level IV, case series.
在现代全踝关节置换（TAR）中使用患者特异性器械（PSI）增强了胫骨部件的定位，无需使用复杂的夹具。这种设计直观地实现了冠状面和矢状面的对齐，并已进行了研究，但尚未研究轴向旋转。本研究的目的是评估 PSI 引导器设定的术前计划轴向旋转与非 PSI 器械确定的术中旋转之间的关系。
这是一项前瞻性队列研究，共纳入 22 例连续病例。从基于术前 CT 扫描的计划中提取内侧沟与胫骨植入物位置之间的轴向旋转角度。在手术时，插入非 PSI 器械的内侧沟定位器，并获得术中轴向照片，以记录 PSI 器械设定的内侧沟与轴向旋转导针之间的角度。比较了这 2 个测量值，并进一步进行了统计分析，包括 Pearson 相关和配对学生 t 检验。
PSI 术前计划中内侧沟与植入物之间的平均轴向旋转角度为 5.4 ± 2.9 度，而内侧沟定位器与导针的术中照片为 5.9 ± 3.8 度。这表明 Pearson 相关系数为 = 0.54， 值为.53。两者的平均差异为-0.46（95%CI：-2.04，1.10），这意味着组件要么轻微外旋，要么叉指向内侧。根据该组数据，50%（11/22）在 2 度以内，77%（17/22）在 4 度以内。
患者特异性引导器允许在现代 TAR 中可重复地植入胫骨旋转部件。需要进一步研究以更好地理解旋转轮廓的生物力学影响及其对存活率的影响。
IV 级，病例系列。
