Comparison of Time Taken in Conventional versus Active Robotic-Assisted Total Knee Arthroplasty.

Background: Computer- and robotic-assisted total knee replacement procedures have been shown to improve the accuracy of the implant size. It also allows dynamic confirmation of the implant and limb alignment during total knee arthroplasty (TKA). The major inhibition of the arthroplasty surgeon in adapting to the robotic-assisted TKA (RA-TKA) is the extra time spent during the registration process and milling of the bone with the robot. The aim of the study was to ascertain the extra time spent during these 2 steps as compared to the conventional TKA (C-TKA). Methods: It is a prospective study involving 30 patients each in the conventional TKA and RA-TKA operated by the same surgical team. The patients were given a choice between the C-TKA and RA-TKA and consecutive 30 cases in each group were studied by an independent observer. In the C-TKA group, the time for the application of appropriate zigs and execution of the bone cuts and soft-tissue release was recorded whereas in the RA-TKA group, the time taken for fixation of the tibial and femoral arrays and bone registration and bone milling with robot and required soft-tissue release was measured. Results: The preoperative patient characteristics were the same in both groups. The time taken in the C-TKA and RA-TKA groups was 24.77 ± 1.92 minutes and 25.03 ± 3.27 minutes, respectively, which is statistically insignificant (p = 0.709). Conclusions: The study findings show that RA-TKA does not take additional time than C-TKA.

Evaluation of the safety and efficacy of the fully automated active robotic system in robotic assisted total knee arthroplasty.

Background: Use of semi-active and active robotic system for performing Total Knee Arthroplasty (TKA) is increasing. The novel fully automated active robotic system performs milling of the bone surfaces with a high speed burr. The aim of the current study was to assess the safety and efficacy of the system in robotic assisted TKA (RA-TKA). Materials and methods: A single center clinical trial was conducted following 30 knees undergoing active RA-TKA for 6 months. Inclusion criteria were patients undergoing RA-TKA for end stage arthritis. Patients undergoing conventional TKA and revision TKA were excluded from the study. Sample size was estimated to be 28 patients with α error of 0.05 and ß error of 0.2 with power of study being 80. A pre-defined list of RA-TKA adverse events was employed to study the safety of the system. Efficacy was judged by comparing the planned versus achieved Implant size, alignment and limb alignment on post-operative radiographs. The post-operative clinical evaluation was done by an independent observer who was not part of the operating team. The primary safety and efficacy hypothesis was tested using a one sided Exact binomial test. The p value < 0.05 was considered significant. Results: Pre-defined adverse events did not occur in any of the 30 RA-TKA (statistically significant p value < 0.001). The implant size accuracy was 100% (30 out of 30 knees) for femoral component and 96.67% (29 out of 30 knees) for tibial component (statistically significant, Chi-squared test, p value 0.0105 and 0.0461 respectively). The implant position and limb alignment was accurate in 100% of patients (p value < 0.001). Conclusion: Early experience of the use of fully automated active robotic system in TKA shows that it is safe and also is effective in achieving accurate implant size and implant/limb alignment.

Efficacy of the Pre-operative Three-Dimensional (3D) CT Scan Templating in Predicting Accurate Implant Size and Alignment in Robot Assisted Total Knee Arthroplasty.

Background: Nearly 20% of Total knee Arthroplasty patients remain dissatisfied. This is a major concern in twenty-first century arthroplasty practice. Accurate implant sizing is shown to improve the implant survival, knee balance and patient reported outcome. Aim of the current study is to assess the efficacy of pre-operative three-dimensional (3D) CT scan templating in a robot-assisted TKA in predicting the correct implant sizes and alignment. Materials and methods: Prospectively collected data in a single center from 30 RA-TKAs was assessed. Inclusion criterion was patients with end stage arthritis (both osteoarthritis and rheumatoid arthritis) undergoing primary TKA. Patients undergoing revision TKA and patients not willing to participate in the study were excluded. Preliminary study of ten patients had indicated almost 100% accuracy in determining the implant size and position. Sample size was estimated to be 28 for 90% reduction in implant size and position error with α error of 0.05 and beta error of 0.20 with power of study being 80. Post-operative radiographs were assessed by an independent observer with respect to implant size and position. The accuracy of femoral and tibial component sizing in the study was compared with the historic control with Chi-squared test. The p value < 0.05 was considered significant. Results: The pre-operative CT scan 3D templating accuracy was 100% (30 out of 30 knees) for femoral component and 96.67% (29 out of 30 knees) for tibial component. The implant position and limb alignment was accurate in 100% of patients. The accuracy of femoral component and tibial component sizing is statistically significant (Chi-squared test, p value 0.0105 and 0.0461, respectively). Conclusion: The study results show the effectiveness of pre-operative 3 D CT scan planning in predicting the implant sizes and implant positioning. This may have a potential to improve the implant longevity, clinical outcomes and patient satisfaction.