Introduction: Medial parapatellar arthrotomy is the standard approach for total knee replacement (TKR) but usually requires adequate arthrotomy repair to allow for early rehabilitation. Nonetheless, no previous studies have clarified the postoperative outcome as quadriceps strength (QS) and functional recovery after using the other simple suture technique for the arthrotomy repair, continuous locking suture (CLS). Methods: 80 patients were randomly assigned into a CLS group (n=40) and an interrupted horizontal mattress (IHM) group (n=40). With the same surgical and rehabilitation protocol, and all arthrotomy repair used only the traditional braided suture. QS was calculated into normalized quadriceps strength (N-QS) and operative leg quadriceps strength compared with contralateral QS (OL-QS). QS, visual analog scale (VAS), modified timed up and go (TUGT) test, Western Ontario and McMasters Universities Osteoarthritis Index [WOMAC] and Knee Society Score [KSS] were followed for 6 months’ period. Results: No significant difference in demographic and perioperative data, except a significant shorter capsular closure time in CLS (233±40 seconds) compared to IHM (388±47 seconds) (p<0.0001). There was no significant difference in N-QS and OL-QS between both groups during the 6-month follow-up period (p>0.05 all). Both groups also did not show any significant difference in the postoperative VAS, TUGT, WOMAC, and KSS (p>0.05 all). Finally, no wound complications or infections manifested during this study. Conclusion: Arthrotomy repair with the CLS technique in TKR and using only the braided suture is safe and effective as demonstrated a recovery of the QS and knee function outcome comparable to the standard IHM technique. Trial registration: This study was registered in Thai Clinical Trials Registry on December 2015 (https://www.clinicaltrials.in.th). The registration number was TCTR20151208003.