Comparison of Conventional Total Knee Arthroplasty Versus Robotic-Assisted Total Knee Arthroplasty in Primary Osteoarthritis of the Knee: A Prospective Comparative Pilot Study

Background: Total knee arthroplasty (TKA) is a highly effective intervention for advanced primary knee osteoarthritis.Conventional TKA (C-TKA) has been the standard of care for decades, while robotic-assisted TKA (RA-TKA) aims to enhance surgical precision and alignment.Prospective Indian data comparing the two are scarce.We therefore conducted a small pilot comparison intended to generate preliminary estimates and inform the design of a future adequately powered randomised controlled trial, rather than to guide current clinical practice.Aim: To obtain preliminary comparative estimates for conventional and robotic-assisted TKA in primary knee osteoarthritis with respect to intraoperative parameters, postoperative pain, functional outcomes, range of motion and complications in an Indian tertiary-care setting, as preparatory work for a properly powered randomised trial.Materials and Methods: A prospective, non-randomised comparative pilot study was conducted on 30 patients with primary knee osteoarthritis (Kellgren-Lawrence grade 3 or 4).Fifteen patients underwent C-TKA with mechanical alignment, and 15 underwent RA-TKA with kinematic alignment; allocation followed patient choice after counselling on both techniques and their costs, and no formal sample-size calculation was performed.Outcomes assessed were tourniquet time, postoperative drain collection, Visual Analogue Scale (VAS) pain score, Knee Society Score (KSS) and knee range of motion in the immediate postoperative period and at 2 weeks and 1, 2 and 3 months.Analysis was performed in IBM SPSS version 26.0, with the Bonferroni method applied to the five repeated time-point comparisons (adjusted significance threshold p < 0.010).Results: Knee Society Scores were significantly higher in the RA-TKA group than in the C-TKA group at every early follow-up time point, and all of these differences remained significant after Bonferroni correction.The between-group gap was widest at 2 weeks (76.9 ± 3.3 versus 87.9 ± 3.5; t = 8.86, df = 28, p < 0.001) and had narrowed by 1 month (97.2 ± 1.7 versus 98.7 ± 1.2; t = 2.79, df = 28, p = 0.006); by 3 months both groups reached a mean KSS of 100.VAS pain scores followed the same pattern and reached 0 in both groups by 3 months.Complications comprised one superficial surgical-site infection (n = 1/15; 6.7%) and three cases of prolonged pain (n = 3/15; 20.0%) in the C-TKA group and one pin-tract infection (n = 1/15; 6.7%) in the RA-TKA group; all were minor and had resolved by final follow-up, and the difference between groups was not statistically significant (Fisher exact test, two-tailed p = 0.330) in a sample of this size.Conclusion: In this pilot cohort, the RA-TKA group had lower drain collection, lower early pain scores, and higher early Knee Society Scores than the C-TKA group despite a longer tourniquet time, with convergence by 3 months.No clinical recommendation follows from these observations.The sample was small and nonrandomised; the two groups differed in alignment philosophy as well as in surgical platform, no radiographic alignment data were obtained, and no cost figures were collected, so the economic comparison remains entirely unquantified.The value of this study lies in the preliminary effect estimates it provides for sample-size calculation in an adequately powered randomised controlled trial with radiographic endpoints, formal health-economic evaluation, and follow-up of at least one year.