Avoiding Orthostatic Intolerance During Early Ambulation After Total Knee Arthroplasty: The Impact of...

Orthostatic intolerance (OI), characterized by dizziness, blurred vision, syncope, can occur during ambulation after total knee arthroplasty (TKA) causing delayed rehabilitation and hospital discharge. Standardized guidelines to prevent OI during early ambulation are lacking. This study aimed to provide evidence regarding the impact of postural transition timing or lying-to-standing time (LTST) on OI during early postoperative ambulation following TKA.

We evaluated 120 patients undergoing unilateral primary TKA for OI with varying LTST. Patients with significant comorbidities, body mass index ≥40 kg/m², or presence of preoperative OI or orthostatic hypotension were excluded. Preoperatively and at 12 hours postoperatively, patients performed three protocols with varying LTST: after changing position from lying to sitting, wait 60 seconds before standing (protocol A), wait 30 seconds before standing (protocol B), and immediate standing (protocol C). Systolic blood pressure, diastolic blood pressure, heart rate, and oxygen saturation were measured at sitting and standing positions for each protocol. OI was defined if signs of cerebral hypoperfusion were detected, or decrease in systolic blood pressure >20 mmHg, or decrease in diastolic blood pressure >10 mmHg.

From 120 TKAs, 98 patients were included (mean age 74 years, mean body mass index 26.46 kg/m²). The incidences of postoperative OI were 0% for protocol A, 16.3% for protocol B, and 44.9% for protocol C. All protocol B patients with OI also experienced it in protocol C.

This study demonstrates that a 60-second sitting interval between lying and standing effectively prevents OI during early ambulation after TKA.