Knee Replacement Surgery: Tourniquet Use, Benefits, and Risks

Is a Tourniquet Used in Knee Replacement Surgery?

Yes, a tourniquet is frequently used in knee replacement surgery (total knee arthroplasty, TKA) to minimize blood loss and improve surgical visibility, although its application is subject to specific clinical considerations and evolving surgical practices.

The Role of the Tourniquet in Knee Arthroplasty

The primary purpose of a surgical tourniquet during knee replacement is to create a bloodless field, which offers several significant advantages for the operating surgeon:

• Reduced Blood Loss: By temporarily occluding arterial blood flow to the lower limb, the tourniquet significantly minimizes intraoperative blood loss. This can reduce the need for blood transfusions, which carry their own risks.
• Improved Surgical Field Visibility: A bloodless field allows the surgeon a clearer view of the anatomical structures, including bones, ligaments, and soft tissues. This precision is critical for accurate bone cuts, implant positioning, and cement application.
• Enhanced Cement Fixation: In cemented knee replacements, a dry surgical field is crucial for optimal bonding between the bone and the prosthetic components. Blood and fluid can compromise the strength and longevity of the cement interface.

How a Tourniquet is Applied

During TKA, a pneumatic tourniquet is typically applied to the upper thigh of the operative leg.

• Placement: The tourniquet cuff, similar to a large blood pressure cuff, is positioned high on the thigh.
• Inflation: Once the patient is anesthetized, the leg is elevated to allow for passive exsanguination (blood drainage) or wrapped with an elastic bandage (Esmarch bandage) to actively push blood out of the limb. The cuff is then inflated to a pressure significantly higher than the patient's systolic blood pressure, typically between 250-350 mmHg, to completely occlude arterial flow.
• Duration: The tourniquet is kept inflated for the duration of the critical surgical steps, often for 60-90 minutes, but typically no longer than 120 minutes to minimize the risk of complications. It is usually deflated before the wound is completely closed.

Potential Benefits of Tourniquet Use

While the immediate benefits of a bloodless field are clear, the overall impact on patient outcomes is a subject of ongoing research.

• Decreased Need for Blood Transfusion: Studies consistently show that tourniquet use reduces intraoperative blood loss and the rate of allogeneic blood transfusions.
• Potentially Shorter Surgical Time: A clear surgical field can allow the surgeon to perform the procedure more efficiently.
• Improved Implant Fixation: As mentioned, a dry field is beneficial for cement polymerization and mechanical interlock.

Potential Risks and Complications

Despite its benefits, tourniquet use is not without potential risks, which is why its application is carefully considered.

• Nerve Palsy: Prolonged or excessive pressure from the tourniquet can cause temporary or, rarely, permanent nerve damage, leading to sensory changes (numbness, tingling) or motor weakness.
• Muscle Ischemia and Damage: The lack of blood flow deprives muscle tissue of oxygen and nutrients, potentially leading to muscle injury, rhabdomyolysis, and post-operative pain.
• Thromboembolic Events: While controversial, some studies suggest a potential link between tourniquet use and an increased risk of deep vein thrombosis (DVT) or pulmonary embolism (PE) due to venous stasis or reperfusion injury.
• Reperfusion Injury: Upon tourniquet deflation, the sudden rush of blood to the ischemic tissues can trigger an inflammatory response, potentially leading to swelling, pain, and, in rare cases, systemic effects.
• Increased Post-Operative Pain and Swelling: Some patients report increased pain and swelling in the immediate post-operative period following tourniquet use, possibly due to muscle ischemia and reperfusion injury.

The Evolving Debate: Tourniquet vs. Tourniquet-Free Surgery

The decision to use a tourniquet in TKA is a topic of ongoing discussion among orthopedic surgeons.

• Arguments for Tourniquet-Free Surgery: Proponents of tourniquet-free TKA argue that it may lead to less post-operative pain, faster quadriceps recovery, reduced incidence of nerve complications, and potentially a quicker return to functional activities. They often rely on meticulous hemostasis (blood control) techniques and hypotensive anesthesia.
• Arguments for Tourniquet Use: Surgeons who prefer tourniquet use emphasize the benefits of a clear field for precision and cement fixation, which they believe contributes to better long-term implant survival and fewer complications related to bleeding.
• Current Trends: There is a growing trend towards minimizing tourniquet time or using lower pressures, and some surgeons have adopted a completely tourniquet-free approach, particularly in patients with significant comorbidities or those at high risk for tourniquet-related complications. The decision often depends on patient factors, surgeon preference, and the specific surgical technique employed.

Conclusion: A Clinical Decision

In summary, the use of a tourniquet in knee replacement surgery is a well-established practice with clear advantages in terms of controlling blood loss and providing a precise surgical field. However, it is associated with potential risks. The decision to use a tourniquet, its duration, and inflation pressure is a clinical one, made by the orthopedic surgeon based on the individual patient's health status, the specific surgical approach, and the latest evidence-based guidelines. Patients should discuss this aspect of their surgery with their surgical team.