Tourniquet Use Does Not Affect Pain and Function after Total Knee Arthroplasty: Patient Evaluation According to Pain Threshold

Abstract We evaluated the effect of using a tourniquet on early-stage pain and 1-year postoperative functional outcomes when patients were divided into two groups according to the pain threshold (PT). Overall, 120 patients who were assessed preoperatively with an algometer were recruited for this prospective, double-blinded, randomized controlled trial. Patients were randomized to undergo total knee arthroplasty (TKA) with a tourniquet (group 1, 60 patients) and without tourniquet (group 2, 60 patients). Primary outcome measures were visual analog scale (VAS) pain scores at 24, 36, and 48 hours postoperatively and functional assessment with Knee Society Score (KSS) test at 1 year postoperatively. No significant differences were observed between groups in terms of gender (49 females and 8 males in group 1 vs. 53 females and 6 males in group 2; p = 0.201) and age (68.9 years in group 1 vs. 68.7 years in group 2; p = 0.811). There was no significant difference between groups in all the VAS and KSS 1 and KSS 2 scores. PT measurements ranged from 2.5 to 11.5 with a mean of 7.69 ± 1.70 and a median of 8. Total 54 patients with a median value of < 8 were defined as the low-PT group, and 62 patients with a median value of ≥ 8 were defined as the high-PT group. When the groups were evaluated according to using the tourniquet, 21 patients were operated on with a tourniquet and 33 patients without it in the low-PT group, while 36 patients were operated on with a tourniquet and 26 patients without it in the high-PT group. There was no significant difference in pain or functional scores between patients when comparing with-tourniquet and without-tourniquet or when comparing the low- and high-PT groups. This showed that the use of a tourniquet during TKA was not associated with either early-stage pain or 1-year postoperative functional outcomes according to algometer evaluation. Level of evidence: Level 1 prospective randomized study.