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Venous haemodynamics in both legs after total knee replacement
M A McNally1, R Bahadur, E A Cooke
1Department of Orthopaedic Surgery, The Queen's University of Belfast, Musgrave Park Hospital, Belfast, Northern Ireland.
Summary
Total knee replacement significantly reduces leg venous blood flow, increasing deep-vein thrombosis risk in early recovery. Mobilization quickly restores flow, highlighting the need for prophylactic devices post-surgery.
Area of Science:
- Orthopedic Surgery
- Vascular Physiology
- Thrombosis Research
Background:
- Total knee replacement (TKR) is a common procedure for knee arthritis.
- Postoperative venous stasis is a known risk factor for deep-vein thrombosis (DVT).
- Understanding altered hemodynamics post-TKR is crucial for DVT prevention.
Purpose of the Study:
- To investigate the impact of total knee replacement on venous blood flow.
- To determine the temporal changes in venous hemodynamics after TKR.
- To compare venous flow alterations after TKR with those observed after total hip replacement (THR).
Main Methods:
- Strain-gauge plethysmography was used to measure resting venous blood flow.
- Measurements were taken pre-operation, post-surgery, and at hospital discharge in 110 TKR patients.
- Hemodynamic data from TKR patients were compared with historical data from THR patients.
Main Results:
- A significant reduction in mean venous capacitance and outflow was observed in the operated leg post-TKR (p < 0.001 and p < 0.004, respectively).
- Venous flow parameters significantly improved after early postoperative mobilization.
- Preoperative venous flow levels were restored by approximately six days after surgery and before hospital discharge.
- Distinct hemodynamic patterns were noted when comparing TKR with THR.
Conclusions:
- Venous stasis following total knee replacement may contribute to deep-vein thrombosis, particularly in the initial postoperative days.
- The early postoperative period represents a critical window for implementing flow-enhancing prophylactic devices.
- Different mechanisms of venous stasis and thrombogenesis likely exist for hip and knee arthritis surgeries.