The arthrotomy repair is one of the most important steps in wound closure after TKR due to the relationship between the extensor mechanism recovery and postoperative wound complications. Although the traditional interrupted suture is considered the standard technique for arthrotomy repair, continuous or running techniques with barbed suture had recently been popular due to the faster closure time, better watertightness, and potential cost reduction [4, 30]. However, to the best of our knowledge, no previous studies had established the data related to the efficacy of CLS on the arthrotomy repair and its related outcomes. This study therefore aimed to evaluate the effectiveness of CLS for the arthrotomy repair in TKR compared to the standard IHM, in terms of quadriceps strength and related functional outcomes.
Our results showed that the arthrotomy repair with the CLS technique significantly decreases the capsular closure time (with the mean difference at 155 seconds, Table 2) without any significant difference in the postoperative QS, functional outcome, operative time, and wound-related complications, compared to the IHM technique, during the 6-month follow-up period (Tables 2 and 3). In terms of the postoperative QS recovery, both groups experienced a significant drop in NQS and OL-QS at 2 weeks, but then recovered 6 weeks after TKR. These findings were different than the previous studies that demonstrated the significant postoperative QS deficit as 59%-62% at the first month and the recovery to the preoperative level at 6 months after TKR [7, 15, 21]. This difference could be explained by the following areas with differences in methodology between the previous studies and the present study: the QS assessment method (electromechanical dynamometer vs. handheld dynamometer), the knee position during the measurement (60o-75o knee flexion vs. 30o knee flexion), the inhibitory effect of preoperative pain and postoperative pain recovery on QS measurement, and the possible effect of blood loss reduction on functional recovery by tranexamic acid injection [9]. However, our findings supported that the postoperative QS deficit in the early postoperative period after TKR could be improved with a meticulous surgical technique with appropriate multimodal perioperative pain management and strict postoperative rehabilitation protocol.
Regarding the postoperative functional outcome after TKR, the CLS groups also showed a non-significant difference in the modified TUGT, WOMAC knee score, and KSS compared to the IHM group during the study period (p > 0.05 all). These findings are comparable to those from previous studies using continuous barbed suture in TKR [4, 15, 19, 30], which can be explained by the successful arthrotomy repair and the uneventful healing of the knee extensor mechanism in both groups during the strict postoperative protocol.
Our results also showed uneventful wound healing response without the incidence of wound complications, such as surgical site infections and reoperation, in both groups during the 6-month follow-up period. These findings were comparable to the previous studies [2, 27], which implied that either the CLS or IHM techniques with traditional braided suture materials are safe. Moreover, the previous studies demonstrated that using barbed suture for superficial wound closure in TKR might be associated with higher risk for wound complications [3, 5, 20].
Our study had some limitations. First, the QS measurement protocol used in this study was slightly different from the previous studies. Due to the evaluation of the QS recovery after arthrotomy repair and the prevention of suture breakage, our study was designed to use HHD and assess QS in 30o knee flexion with the earliest follow-up visit as 2 weeks, whereas the previous studies on QS recovery after TKR were performed using various measurement tools (such as isokinetic dynamometer, electromechanical dynamometer, or chair-fixed dynamometer) and testing in knee positions varying from 30o to 75o knee flexion with the earliest follow-up visit at 1 month [9, 15, 21, 26]. Moreover, the reliability of the QS assessment in some patients might be affected by the knee pain as the mean VAS at 2 weeks postoperatively was 2.9 ± 18 in the CLS group and 2.2 ± 1.4 in the IHM group (Fig. 4). Therefore, although HHD had been known for its reliability for patients undergoing TKR [8, 11, 14], our results could not be directly compared with the previous studies. Second, although this study was a double-blinded RCT, our sample size was relatively small and might not detect some postoperative complications related to the CLS technique, such as suture breakage or wound infection. Third, our study did not explore the other factors that might affect the QS recovery, such as surgeon experience [13], prosthesis design [7], and the use of barbed suture [25]. Therefore, future prospective and multicenter RCTs with a large sample size are required to assess the effect of CLS in the general population.