EARLY OUTCOMES OF NEW CEMENTLESS TOTAL KNEE ARTHROPLASTY DESIGN: A RETROSPECTIVE COHORT ANALYSIS

Background Cementless total knee arthroplasty (TKA) has gained interest due to potential benefits in biologic fixation and long-term durability. This study compared early outcomes among cementless TKA performed with robotic assistance, cemented TKA performed with robotic assistance, and historical cemented TKA performed with manual instrumentation. Methods A retrospective analysis compared three single-surgeon cohorts: 173 patients who underwent cementless, robot-assisted TKA; 188 patients who underwent cemented, robot-assisted TKA; and 707 patients who underwent cemented TKA with manual instrumentation. All patients had a minimum of 1 year of follow-up. Demographics, early postoperative complications, and patient-reported outcomes (PROs) were analyzed. PROs included PROMIS Physical Function and KOOS JR. Multivariable logistic regression was performed for manipulations under anesthesia (MUA), aseptic revision, and infection within 2 years, controlling for age, sex, and BMI. The cohorts differed in sex distribution, age, and BMI (all p<0.05). Results There were no significant differences among the cemented/manual, cementless/robotic, and cemented/robotic cohorts in MUA (3.4%, 2.9%, and 4.3%, respectively; p=0.766), aseptic revisions (0.9%, 1.2%, and 0.5%; p=0.810), or infections (1.4%, 1.7%, and 1.1%; p=0.863). Adjusted analyses of were also not statistically significant. The cementless cohort had higher preoperative PROMIS Physical Function scores than the cemented/manual cohort (p<0.001) and lower preoperative KOOS JR scores (p=0.049). Although early postoperative recovery differed at selected time points, no significant PRO differences were observed after 6 weeks post-operatively, and changes from baseline did not differ among cohorts. Conclusion Cementless TKA demonstrated short-term clinical outcomes comparable to both cemented manual and cemented robot-assisted TKA. Despite demographic and baseline PRO differences, early complication rates and later PRO recovery were similar among the three cohorts, indicating that cementless design does not compromise early recovery. Future studies investigating other cementless implants may help validate whether the observed similarities in outcomes are attributable to cementless fixation rather than implant design.