Is There an Advantage to Knotless Barbed Suture in TKA Wound Closure? A Randomized Trial in Simultaneous Bilateral TKAs

Effective wound closure is critical to minimizing wound complications and withstanding the forces associated with early knee motion after TKA. Barbed sutures allow for knotless fixation, have been used successfully in other specialties, and may provide for more even distribution of tension along the length of the incision; however, data regarding unidirectional barbed sutures from randomized trials have raised important concerns about their use. Bidirectional barbed sutures offer a potential alternative, but have not been studied extensively in orthopaedic surgery.

Using a prospective, randomized, within-patient controlled study design I compared wound closure performed with bidirectional barbed sutures in one knee of bilateral TKAs performed under the same anesthetic with those performed with standard sutures in the other knee to determine whether the barbed suture was associated with (1) faster closure times; (2) fewer intraoperative suture issues, such as needle sticks or suture breakage, and fewer postoperative wound complications; (3) no detrimental effect on clinical outcomes, including knee ROM and Knee Society scores; and (4) lower total operative cost, considering suture material cost and operating room time savings.

Between 2011 and 2012, 50 consecutive patients meeting prespecified inclusion criteria with simultaneous bilateral TKAs had deep and superficial closures performed using interrupted and running standard sutures in one randomly assigned knee, and running knotless bidirectional barbed sutures in the other knee. The barbed suture is US FDA-approved for soft tissue approximation wherever absorbable sutures are appropriate. Intraoperative suture issues and the number of sutures used were recorded at the time of wound closure. Suture cost was compared between the standard and barbed sutures and measured against the operative time cost, as estimated per minute saved. Patients were followed postoperatively at 2, 6, and 12 weeks, and 1 year. Outcomes assessed included detailed operative and tourniquet time, knee ROM, Knee Society scores, postoperative complications, use of antibiotics, and any subsequent surgical interventions. These outcomes were assessed at each visit except for Knee Society scores which were collected at the 12-week and 1-year evaluations. All patients completed followups up to the final evaluation at 1 year.

Mean wound closure time was 4.7 minutes less using barbed sutures (SD, ± 2.8; 95% CI, −5.5 to −3.7; p < 0.001), average 16.1 (SD, ± 2.2) versus 11.4 (SD, ± 2.2) minutes for the standard versus barbed suture types, respectively. Overall tourniquet time was not different at 78.7 minutes (SD, ± 11.1 minutes) versus 74.9 minutes (SD, ± 10.1 minutes), respectively (p > 0.1). There were no intraoperative clinical issues, such as provider or patient injury, using either suture. There were no needle disengagements or suture breakages with barbed-suture closure; five episodes of premature disengagement of the suture from the needle and three suture breakages were observed with standard closures (p < 0.005). There were no postoperative wound dehiscences or disruptions of the arthrotomy closure with either closure technique. Final ROM was not different with the numbers available (barbed-suture group mean, 126.7° ± 6.9° SD vs standard-suture group mean, 125.6° ± 7.0° SD; p = 0.4, 95% CI, −3.77 to 1.73) between patient groups at 1 year. There were no differences with the numbers available in 1-year Knee Society knee scores (barbed mean, 92.8 ± 6.69 SD vs standard mean, 93.3 ± 6.2 SD; p = 0.6, 95% CI, −1.97 to 3.36). Considering suture material cost against time savings in operating room time, there was a cost savings of mean USD 175 per case when using barbed suture.

In this randomized controlled trial, I found knotless bidirectional barbed suture to be more efficient in terms of closure time and lower in direct operative cost than conventional suture material, while showing no difference in terms of Knee Society knee scores, ROM, or wound appearance with the numbers available. Future studies with larger numbers will be needed to compare overall costs of care and to detect uncommon complications that might arise, although none were observed in this small series.

Level I, therapeutic study.