No effect of tourniquet in primary total knee arthroplasty on muscle strength, functional outcome, patient satisfaction and health status: a randomized clinical trial

Tourniquet use during primary total knee arthroplasty (TKA) may negatively impact the early postoperative functional recovery due to molecular effects of ischaemia. The hypothesis of the present study was that primary TKA without a tourniquet positively influences the postoperative muscle strength, functional outcome, patient satisfaction and health status.

The monocentric, randomized, controlled trial included a total of 99 patients scheduled to undergo primary TKA (ClinicalTrials.gov NCT02475603). The patients were randomly assigned to the tourniquet (n = 50) or non-tourniquet (n = 49) group after receiving a written informed consent. As primary outcome parameter, the functional outcome, patient expectation/satisfaction and the health status were assessed preoperatively, 6 weeks, 6 months postoperatively using Oxford knee score, WOMAC score, Mancuso score, EQ-5D index, EQ-VAS, anxiety score, depression score, hospital anxiety and depression scale, respectively. Additionally, a rope pulley isokinetic system (Moflex, Recotec/Bernina, Switzerland) was applied to quantify the muscle strength preoperatively, 1 week, 6 weeks and 6 months postoperatively.

No difference in any of the outcome parameters could be observed between the groups at all time points after TKA (n.s.). Also the isokinetic muscle strength of the knee joint as quantified by concentric/eccentric peak force (N), workload (J), total workload (J) and power (W) did not reveal statistically significant differences between the groups and time points. However, in both groups improved results were found with respect to the functional outcome, patient satisfaction, health status and isokinetic muscle strength up to 6 months postoperatively.

The application of the tourniquet did not affect the isokinetic muscle strength, the functional outcome, the patient satisfaction and the health status following primary TKA. However, with and without tourniquet use, the level of the knee functionality, the patient satisfaction as well as the health status improved significantly.

I.