Preoperative carbohydrate drink in fast-track primary total knee arthroplasty: a randomized controlled trial of 168 patients.

A key component in fast-track total knee arthroplasty (TKA) is early mobilization. Preoperative fasting might cause orthostatic hypotension and -intolerance which both can interfere with early mobilization. It was hypothesized that consuming a carbohydrate drink 2-3 hours prior to surgery is a viable option to reduce orthostatic hypotension, and as a result, improve rehabilitation. In this randomized controlled trial, all consecutive unilateral primary TKA patients were reviewed for eligibility. Exclusion criteria were American Society of Anesthesiologists (ASA) class above 3, older than 80 years of age, Diabetes Mellitus, and an insufficient comment of Dutch language. Patients were distributed in two groups. The control group was allowed to eat till 6 hours and drink clear fluids till 2 hours before surgery (standard treatment). The intervention group consumed, additionally to the standard treatment, a carbohydrate drink 2-3 hours before surgery. Blood pressure was measured both lying and standing as a measure for orthostatic hypotension during first time postoperative mobilization on day of surgery. A total of 168 patients were included. Prevalence of orthostatic hypotension in the control- and intervention group was 24 patients (34%) and 14 patients (19%) respectively, (p=0.05). Prevalence of orthostatic intolerance was 13 patients (19%) in the control group and 9 patients (13%) in the intervention group (p=0.32). No drink related adverse events occurred. In conclusion, taking a carbohydrate drink 2-3 hours before TKA significantly lowers the number of patients with orthostatic hypotension in early mobilization. However, the clinical relevance of the carbohydrate drink has to be studied further.