Purpose <p>To evaluate whether continuous barbed suturing improves postoperative pain, closure efficiency, and early functional outcomes compared to conventional interrupted suturing in primary total knee arthroplasty (TKA).</p> Methods <p>In this double-blinded randomised controlled trial, 143 patients undergoing primary TKA were assigned to continuous barbed (<i>n</i> = 72) or interrupted absorbable (<i>n</i> = 71) sutures for arthrotomy and subcutaneous closure. The primary endpoints were closure time and postoperative pain at 24&#xa0;h; superiority testing was pre-specified only for VAS at 24&#xa0;h (one-sided t-test, α = 0.025), whereas closure time was analysed two-sided (α = 0.05). Secondary outcomes included wound healing time, 6-month functional gain (Hospital for Special Surgery score), quality of life (EQ-5D), satisfaction, and complications.</p> Results <p>Continuous suturing significantly reduced closure times for both arthrotomy (4.2 ± 1.6 vs 6.5 ± 7.7&#xa0;min; <i>p</i> &lt; 0.001) and subcutaneous layers (4.8 ± 1.9 vs 5.6 ± 1.4&#xa0;min; <i>p</i> &lt; 0.001). Pain at 24&#xa0;h was significantly lower in the continuous group (VAS 2.9 ± 2.1 vs 4.0 ± 2.1; <i>p</i> = 0.017). The continuous group also showed faster wound healing (22.3 vs 24.8 days; <i>p</i> = 0.012) and greater 6-month HSS improvement (24.5 vs 16.0 points; <i>p</i> = 0.040). No significant differences were observed in complication rates, satisfaction, or quality of life.</p> Conclusion <p>Continuous barbed suturing improves surgical efficiency, reduces early postoperative pain, accelerates wound healing, and enhances functional recovery without increasing complication rates. This is the first randomised trial to demonstrate superior functional recovery (HSS score) with barbed continuous closure over traditional interrupted techniques, supporting its broader adoption in primary TKA.</p> Level of evidence <p>Level I, randomised controlled trial.</p>