Tourniquet Use Independently Predicts Early Quadriceps Inhibition Following Primary Total Knee Arthroplasty: A Dose-Response Analysis.

BACKGROUND: The purpose of the study was to evaluate the effect of tourniquet use on early postoperative quadriceps muscle function following primary total knee arthroplasty (TKA) and to identify independent predictors of quadriceps muscle inhibition. METHODS: In this retrospective comparative cohort study, 110 consecutive patients undergoing primary unilateral TKA were included. Patients were allocated to tourniquet (n = 57) or tourniquet-free (n = 53) groups based on a temporal change in surgical practice. Quadriceps muscle inhibition was defined as the inability to perform an active straight leg raise (SLR) with the knee in full extension. Straight leg raise performance was assessed on postoperative days one and three by a blinded independent observesr. Multivariable logistic regressions were used to determine independent predictors. RESULTS: Quadriceps muscle inhibition was more frequent in the tourniquet group (40.4 versus 18.9%, P = 0.023), while SLR performance on postoperative day one was higher in the tourniquet-free group (52.8 versus 28.1%, P = 0.008). Multivariable analyses identified tourniquet use (odds ratio [OR] = 6.25, P = 0.002), body mass index (BMI) (OR = 1.23, P = 0.003), and operative duration (OR = 1.48, P < 0.001) as independent predictors. The model demonstrated good discrimination (area under the curve [AUC] = 0.834). A significant dose-response relationship was observed between tourniquet duration and inhibition risk (OR = 1.65, P < 0.001). CONCLUSION: Tourniquet use is independently associated with impaired early quadriceps muscle recovery after TKA, with a dose-dependent effect. Higher BMI and longer operative duration further increase risk, supporting a patient-specific approach to tourniquet use.