Uncemented total knee arthroplasty is associated with higher complication rates: a propensity-matched retrospective study

Modern uncemented total knee arthroplasty (TKA), is considered an alternative to the traditional cemented fixation, especially for younger and highly active patients; however, questions remain regarding its comparative complication profile, specifically in the early postoperative period. The purpose of this study was to determine the rate of postoperative complications associated with both cemented and uncemented TKA by using a large, national database. We conducted a retrospective cohort study using the TriNetX Research Network, which aggregates deidentified electronic health record (EHR) data from over 127 million patients. Adults who underwent their first primary TKA between October 1, 2012, and October 1, 2020, with a minimum of three years follow-up were included in the analysis. After applying inclusion/exclusion criteria, 4135 cemented TKAs were 1:1 matched to 4135 uncemented TKAs using a propensity score matching based on demographic variables and comorbidity. Follow up assessments were made at 90 day, 1 year, and 3 year intervals included prosthetic joint infection (PJI), revision procedures, aseptic loosening, periprosthetic fracture, dislocation, and all-cause complications, defined as the sum of the prosthetic joint infection (PJI), revision procedures, aseptic loosening, periprosthetic fracture, dislocation. In the matched sample (n = 4,135 per group), cemented TKA was associated with lower rates of PJI at 90 days (OR 0.525, 95% CI 0.334–0.824) and 1 year (OR 0.695, 95% CI 0.505–0.956). Cemented fixation was also associated with reduced all-cause complications at 90 days (OR 0.568, 95% CI 0.361–0.824), 1 year (OR 0.671, 95% CI 0.511–0.882), and 3 years (OR 0.765, 95% CI 0.697–0.963). No clinically significant differences existed between the two groups regarding aseptic loosening or periprosthetic fractures. Using a large, propensity matched group of patients, we found that Cemented TKA demonstrated statically significant lower rates of PJI and all-cause complications compared with Uncemented TKA. These findings suggest potential differences in short-term outcomes between fixation types, although causality cannot be inferred due to the observational nature of the study and limitations inherent to database research, including coding variability and the absence of implant-level detail. Future studies should include design aspects of the implants, as well as surgeon-specific characteristics and extended follow up.