Effect of Tourniquet Use on 3D Cement Penetration and Mid-Term Implant Stability in Primary Total Knee Arthroplasty

BACKGROUND: The effect of tourniquet use on cement penetration in primary total knee arthroplasty (TKA) remains controversial. Current assessments rely primarily on radiograph-based 2D measurements, which limit the precision and comprehensiveness of analysis. Therefore, this study investigated the effect of tourniquet use on 3D cement penetration and the association of tourniquet use with mid-term implant stability. METHODS: In this prospective randomized controlled trial, 141 Han Chinese (East Asian) patients (mean age, 68.3 years; 85% female) were allocated to 1 of 3 groups: tourniquet (Group A), no tourniquet (Group B), and tourniquet during cementation only (Group C). The primary outcomes were 3D cement penetration (thickness, volume, surface area) and mid-term implant stability assessed on the basis of radiolucent lines (RLLs) and survivorship. Cement penetration metrics across femoral and tibial components were systematically quantified through 3D morphological analysis of metal artifact reduction-computed tomography (MAR-CT) images reconstructed using Avizo software (Thermo Fisher Scientific). Secondary outcomes included blood loss, inflammatory and muscle-injury biomarkers, pain scores, functional scores, postoperative length of stay, and complication rates. RESULTS: All participants were followed for 5 years. No significant intergroup differences in cement penetration (thickness, volume, surface area) around the tibial (p = 0.847, p = 0.473, and p = 0.395, respectively) and femoral (p = 0.203, 0.201, 0.399) components were observed. Cement thickness correlated with preoperative knee deformity but not with implant size. Additionally, Group B demonstrated superior clinical outcomes versus Groups A and C: lower levels of inflammatory and muscle-injury biomarkers, lower early pain scores, and a shorter hospital stay, with enhanced 3-month knee function demonstrated in Groups B and C versus Group A. Total blood loss, mid-term outcomes, and complication rates were comparable. No RLLs or revisions were observed, and the 5-year implant survival rate was 100%. CONCLUSIONS: Tourniquet use showed no significant effect on cement penetration and mid-term implant stability in primary TKA, and omitting intraoperative tourniquet use was associated with better early postoperative functional recovery in patients undergoing TKA. LEVEL OF EVIDENCE: Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.