Summary

Immediate and early postoperative pain in total knee replacement surgery is not affected by the use of robotic assistance.

Abstract

Introduction

The use of robotic assistance (RA) in total knee arthroplasty (TKA) has been associated with improvements in component alignment accuracy, reduced hospital stay, and decreased surgical errors. However, the evidence regarding its influence on postoperative pain is controversial. Additionally, the heterogeneity of prosthesis models and types of assistance makes the results non-extrapolable from one model to another.

Objective

To determine if there are differences in postoperative resting pain on days 1, 2, 7, and 30 post-surgery in patients undergoing TKA with imageless RA compared to those undergoing TKA with the same prosthesis model under the conventional technique (CT).

Method

A retrospective non-concurrent cohort study. The sample included 108 consecutive patients who underwent TKA surgery under the same anesthetic protocol and hospital analgesic regimen between March and July 2023, divided into two groups: 47 patients with imageless RA and 61 with CT. Demographic data and comorbidities were collected from medical records. Postoperative resting pain was assessed by evaluators blinded to the surgical technique and was collected in person on days 1 and 2 using the visual analog scale (VAS) for pain and through the use of rescue analgesia via patient-controlled analgesia (PCA), and on days 7 and 30 by telephone interview using the VAS. Mann-Whitney tests were used to compare VAS means between groups at each time point, Fisher's exact test for PCA use, and Chi-square test for other categorical variables, with

Significance

level of P<0.05.

Results

The mean age was 67 years (range 36-85), with 27.8% of the patients being male, and 87.9% of the patients having some type of comorbidity. Both groups were comparable in their demographic variables and relevant comorbidities.
The average pain measured by VAS on day 1 was 1.89 (95% CI: 1.31-2.47) in the RA group and 2.18 (95% CI: 1.60-2.77) in the CT group. On day 2, it was 1.45 (95% CI: 0.82-2.08) and 1.63 (95% CI: 1.02-2.25), respectively. Additionally, 45 out of 47 patients used PCA in the RA group, and 60 out of 61 in the CT group.
No significant differences were observed in postoperative pain between the groups on day 1 (p = 0.425), day 2 (p = 0.690), or in PCA use (p = 0.578).
The mean VAS scores were 3.51 (95% CI: 3.13-3.89) in the RA group and 3.47 (95% CI: 3.01-3.93) in the CT group on day 7, while on day 30, they were 2.60 (95% CI: 2.15-3.06) and 2.41 (95% CI: 2.07-2.76), respectively. No significant differences were observed between the two groups in these measurements (p = 0.888 and p = 0.516, respectively).

Conclusion

No statistically significant differences were observed in postoperative pain or analgesic requirements between patients who received TKA with RA and those who received TKA with CT on days 1, 2, 7, and 30 post-surgery. Future prospective randomized studies are needed to confirm these findings.