Department of Orthopaedics, Sir H. N. Reliance Foundation Hospital and Research Centre, Mumbai, India.
Clin Orthop Surg. 2021 Sep;13(3):358-365. doi: 10.4055/cios20226. Epub 2021 Apr 12.
Optimal placement of the components and achieving a neutral mechanical axis are the main goals of total knee arthroplasty (TKA). Different computerised navigation systems are presently used for these purposes. This aim of this study was to compare the pinless navigation (PNA) TKA performed using iAssist with the conventional instrumented (CIN) TKA in terms of functional and radiological outcomes.
A total of 100 knees operated for TKA by a single surgeon were studied retrospectively for a period of 2 years. Weight-bearing postoperative radiographs of the knees along with scanograms of the lower limbs were used for measurements of component positioning, mechanical axis alignment, and number of outliers. Oxford knee scoring was used for functional analysis.
No statistically significant difference was seen in the mean mechanical axis alignment (hip-knee-ankle angle), coronal alignment (α and β angles) and sagittal alignment (γ and δ angles) of the femoral and tibial components between the two groups. Though the percentage of outliers for mechanical axis alignment was lower in the PNA-TKA group than in the CIN-TKA group, the difference was not statistically significant ( = 0.73). The number of outliers for the femoral and tibial component positioning in coronal and sagittal planes was not statistically significantly different between the two groups. No statistically significant difference ( = 0.68) was noted between the two groups with respect to the Oxford Knee Score. The mean surgical time was greater in the PNA-TKA group by 11 minutes, which was statistically significantly longer ( = 0.018). Complications were seen in 6.89% of the cases in the CIN-TKA group, while none in the PNA-TKA group.
The accurate mechanical axis alignment and component positioning can be achieved with the conventional instrumentation, so the use of PNA system, which adds to the surgical cost, is questionable. Also, equally good short-term functional outcome can be achieved with the conventional instrumentation. The surgeon must be accustomed with the instrumentation of the PNA system, or it adds to the surgical time.
全膝关节置换术（TKA）的主要目标是优化组件的放置位置并实现中立的机械轴。目前，不同的计算机导航系统用于实现这些目标。本研究的目的是比较使用 iAssist 进行的无钉导航（PNA）TKA 与传统器械（CIN）TKA 在功能和影像学结果方面的差异。
回顾性研究了一位外科医生在 2 年内对 100 例膝关节进行 TKA 的情况。使用术后膝关节负重位 X 线片和下肢扫描片测量组件位置、机械轴对准情况和离群值的数量。使用牛津膝关节评分进行功能分析。
两组患者股骨和胫骨组件的平均机械轴对准（髋膝踝角）、冠状面对齐（α和β角）和矢状面对齐（γ和δ角）无统计学差异。尽管 PNA-TKA 组机械轴对准的离群值百分比低于 CIN-TKA 组，但差异无统计学意义（=0.73）。冠状面和矢状面股骨和胫骨组件位置的离群值数量在两组之间无统计学差异。两组间牛津膝关节评分无统计学差异（=0.68）。PNA-TKA 组的平均手术时间比 CIN-TKA 组多 11 分钟，差异有统计学意义（=0.018）。CIN-TKA 组有 6.89%的病例出现并发症，而 PNA-TKA 组无并发症。
使用传统器械可以实现准确的机械轴对准和组件定位，因此使用增加手术成本的 PNA 系统是值得怀疑的。此外，使用传统器械也可以获得同样良好的短期功能结果。外科医生必须熟悉 PNA 系统的器械操作，否则会增加手术时间。
