Adverse Outcomes After Cemented and Cementless Primary Elective Total Hip Arthroplasty in 60,064 Matched Patients: A Study of Data From the Swedish Arthroplasty Register.

Introduction: The choice between cemented and cementless fixation in primary elective total hip arthroplasty (THA) remains a subject of ongoing debate. However, comparisons between the two are subject to limited adjustments for patient characteristics, diagnoses, and surgical factors, as well as by limited outcome time endpoints. Our study aimed to compare the effect of femoral fixation on safety and implant survival outcomes in matched patients.

Methods: Using propensity score techniques, we matched patients undergoing cemented (n = 101,523) and cementless (n = 52,996) primary elective THA in the Swedish Arthroplasty Register (SAR) based on age, sex, American Society of Anesthesiologists (ASA)grade, body mass index (BMI), hospital type, and pre-operative diagnosis between 2008 and 2018. We used both regression and survival models for 30, 60, and 90 days, as well as one and two years, to compare outcomes, including mortality, revision, and periprosthetic femoral fracture necessitating revision surgery.

Results: There were 30,032 cementless femoral fixations one-to-one matched with cemented ones using the Gradient Boosting Machine (GBM) modeling to estimate the propensity score. Regression analyses showed that cementless fixation had lower mortality outcomes (OR [odds ratio] 0.73, 95% CI [confidence interval] 0.69 to 0.78, P < 0.001), but significantly worse revision (OR 1.51, 95% CI 1.38 to 1.65, P < 0.001) and periprosthetic femoral fracture (OR 2.40, 95% CI 1.92 to 2.99, P < 0.001). Kaplan-Meier survival models showed statistically significant lower mortality risks for uncemented fixation at the 2-year interval (HR [hazard ratio] 0.82, 95% CI 0.71 to 0.94, P = 0.006), but not at earlier endpoints. Revision and periprosthetic femoral fractures were both higher for cementless rather than cemented fixation.

Conclusion: This study found no significant differences in early mortality between cemented and cementless femoral implants. However, cementless fixation was associated with increased risks of revision and periprosthetic femoral fractures. These findings emphasize the importance of considering implant choice in the context of individual patient characteristics and surgical priorities to optimize outcomes in total hip arthroplasty.