Erratum to: Does Robotic-assisted TKA Result in Better Outcome Scores or Long-term Survivorship Than Conventional TKA? A Randomized, Controlled Trial.

Abstract

There are inconsistencies between some of the data in the Methods and Results sections of the Abstract and the Methods and Results sections in the main text. Additionally, there are some sentences in the Discussion section that are unclear. We will clarify those inconsistencies and provide more precise sentences below. The data in the last sentence of the Methods section in the Abstract is incorrect and does not match the data in the Methods section of the main text. The sentence should read: “To minimize the chance of type-2 error and increase the power of our study, we assumed the difference in the Knee Society score to be 25 points to match the MCID of the Knee Society score with a SD of 5; to be able to detect a difference of this size, we calculated that a total of 628 patients would be needed in each group in order to achieve 80% power at the α = 0.05 level.” Next, there are multiple errors in the Results section of the Abstract. The third-to-last sentence in the Results section of the Abstract is incorrect and does not match the data in the Results section of the main text. The sentence should read: “In all, 0.6% of knees (four) in each group had a superficial infection, and they were treated with intravenous antibiotics for 2 weeks.” Similarly, the data in the last sentence in the Results section of the Abstract is incorrect and does not match the data in the Results section of the main text. The sentence should read: “In the conventional TKA group, 0.6% of knees (four) had motion limitation (< 60°).” Moving to the main text, in the Patients and Methods section, Fig. 1 has an error. The total number of knees in the CONSORT flow diagram should be: “1965 knees”. The third sentence under Statistical Analysis in the Patients and Methods section is incorrect. The sentence should read: “We performed an a priori sample size calculation using what we believed to be a clinically relevant difference in the Knee Society score of 25 points (which was the MCID of that score as reported by Lee et al. [21]), with an SD of 5 points. For this calculation, we set the power to 80% (β = 0.20) and α to 0.05. This calculation showed that a total of 628 patients would be needed in each group.” In the Discussion section, the last sentence of the first paragraph is unclear. The sentence should read: “Although we found a small reduction in the proportion of knees aligned 0° to 3° away from neutral when robotic assistance was used, we found no between-group difference in outliers more severe than 3°, and no reduction in aseptic loosening in the robotic-assisted group.” Finally, the second sentence of the last paragraph in the Discussion section is not as precise as it should be. The sentence should read: “Although we observed a small improvement in the proportion of knees with a 0° to 3° deviation from a neutral mechanical axis in the robotic TKA group, there was no such difference if the definition of an outlier was taken to be > 3° as is commonly done.” The authors of the study apologize for these errors.