Lower tourniquet pressure does not affect pain nor knee-extension strength in patients after total knee arthroplasty: a randomized controlled trial.

PURPOSE

The use of a tourniquet in total knee replacement has advantages and drawbacks. Some studies suggest that using ischaemia at low pressures could reduce its negative effects. Our objective is to verify whether the use of ischaemia at low pressures (100 mmHg above the systolic blood pressure) produces greater pain and loss of strength than surgery without a tourniquet.

METHODS

By the means of a prospective randomized clinical trial, patients were assigned to the control group (no tourniquet, NT) or the experimental group (tourniquet, T). The main variables measured were pain (VAS) and isometric muscle strength (preoperatively, 10 days and 3 months after surgery). Secondary variables were haemoglobin at 24 h, transfusion index, need for rescue drugs and days of admission.

RESULTS

A total of 71 patients (73 prosthesis) were studied. Both groups were homogeneous in terms of age, body mass index, sex ratio, preoperative strength and level of anesthetic risk. We did not find significative differences in any of the main variables (pain and strength) nor in the secondary ones. We could only find differences in the days of admission (2.77 vs. 3.05; p = 0.031).

CONCLUSIONS

Use of a tourniquet at low pressures (100 mmHg above systolic blood pressure) did not result in an increase in postoperative pain or a decrease in quadriceps extension force within the first 3 months after surgery.

LEVEL OF EVIDENCE

Level 1-Randomized controlled trial.