Tourniquet on Total Knee Arthroplasty

Functional recovery after total knee arthroplasty (TKA) has seen dramatic improvement over the past 20 years through advances in surgical technique, implant design, perioperative pain management strategies, and physical therapy protocols. Tourniquet use during TKA, however, remains controversial due to conflicting reports in the literature on these benefits and risks of its use. Reported advantages of tourniquet use include improved visualization of the surgical field and decreased intraoperative blood loss. Reported disadvantages of tourniquet use include increased postoperative pain and slower functional recovery as a direct result of the pressure of the tourniquet on the thigh during the procedure.

Traditionally with tourniquet use during TKA, the limb is exsanguinated and the tourniquet is raised to a fixed, pressure at the beginning of the case, typically 250mmHg to 350mmHg, and let down after closure. A novel tourniquet design that adjusts the tourniquet pressure in real-time based on intraoperative patient blood pressure measurements. This design may allow for the tourniquet to be inflated at a lower mean pressure while still maintaining efficacy.

A prospective study comparing total blood loss, pain and functional recovery after TKA using this novel tourniquet design, design (Zimmer A.T.S.® 4000TS Automatic Tourniquet System, with disposable contour cuffs) and TKA without tourniquet would further the current literature. Total blood loss will be calculated by previously validated methods. Pain and functional recovery will be closely monitored throughout the postoperative period using a patient wearable activity tracker (FitBit Inspire HR) and a smartphone-based patient engagement platform with integrated digital surveys paired with smart-brace based home PT assessments (FocusMotion).Pain and functional recovery will be closely monitored throughout the postoperative period using a patient wearable activity tracker (FitBit Inspire HR) and a smartphone-based patient engagement platform with integrated digital surveys paired with smart-brace based home PT assessments (FocusMotion). Applying this technology to the proposed study can help identify problematic pain that is not appreciable during admission; given the fact that markers of inflammation and myocyte damage increase over time until at least post-operative day 3, it is possible that TKAs performed under tourniquet may have pain and narcotic requirements not appreciated with short-stay admissions . The proposed study will further the literature on pain and narcotic use in the early time period after TKA, and will help identify if tourniquet has an effect on these variables.

Furthermore, sleep quality is a component of functional recovery and is correlated with pain. Knee osteoarthritis affects general quality of life by increasing sleep disturbance and nighttime wakening, and this is correlated with the pre-operative radiographic severity of disease. Sleep quality is affected in the immediate post-operative period after TKA as well, but improves by 3-6 months post-operatively . The proposed study would be the largest prospective study investigating the effect of TKA on pain and sleep quality, as well as being the first to investigate tourniquet use as a factor affecting sleep quality and pain. The proposed study would be the first to collect both subjective and objective data on the subject, using validated survey measurements as well as the data collected by the Fitbit Inspire HR device.

Inclusion criteria

• Age 18 and up
• Primary unilateral TKA
• BMI<45
• Primary diagnosis of osteoarthritis
• Patient has a iOS or Android smartphone capable of running FitBit and FocusMotion applications

Exclusion criteria

• Revision TKA
• Bilateral TKA
• Pregnancy
• Prisoners
• Pre-existing functionally-limiting neurologic disorder
• Narcotic dependence, defined as oxycodone/hydrocodone use >5days/week
• History of unprovoked VTE/PE
• Inability to complete baseline functional testing