Tourniquet Pressure in Primary Total Knee Arthroplasty

This proposed novel randomized control trial (RCT) seeks to address this gap in TKA protocol by gaining a better understanding of the relationship between tourniquet pressure and time, and intraoperative performance and post-operative outcomes. This study does not seek to answer the question of "tourniquet vs no tourniquet", but to seek a tourniquet usage that would maximize the intraoperative benefits for the surgeon and minimize the negative consequences for patient outcomes.

Specific Aim #1: enroll around 146 primary TKA patients.

Specific Aim #2: evaluate different tourniquet cuff pressures (TCP) and tourniquet times in relation to intraoperative performance.

Specific Aim #3: evaluate different TCP and tourniquet times in relation to post-operative pain and complications of short-term, intermediate, and long-term followup.

Specific Aim #4: evaluate different TCP and tourniquet times in relation to post-operative function of short-term, intermediate, and long-term followup.

The overall goal of the project is to evaluate the relationship of two variables: 1) tourniquet cuff pressure (TCP); and 2) tourniquet time (i.e. duration of inflation) during primary TKA relative to three categories of outcomes: 1) intraoperative performance; 2) post-operative pain and complications; and 3) post-operative complications.

Design

This study will use a randomized controlled trial that is double-blinded. The co-investigator, Mark Nazal, along with the principal investigator, Dr. Maxwell Langfitt, will work with the Orthopaedic Clinic Research Coordinator to recruit around 146 patients. Mark Nazal will then randomize these patients into one of six tourniquet cuff pressure (TCP) groups:

1. 220 mmHg 4) 300 mmHg
2. 250 mmHg 5) 325 mmHg
3. 275 mmHg 6) 350 mmHg

The primary TKA procedure will be performed by one of the three fellowship-trained orthopedic surgeons at Wake Forest Baptist Hospital (Dr. Maxwell Langfitt, Dr. Jason Lang, and Dr. John Shields). The orthopedic surgeon and the patient will be blinded to the TCP assignment and will not be told what tourniquet pressure is being applied. The OR nursing team will be told what the patient's assigned TCP is in order to perform the actual inflation.

Data collection will include short-term data: post-operative day 1 (POD1), post-operative day 2 (POD2), and 2-week followup; intermediate data: 6-week and 12-week followup; and long-term data: 1-year followup.

The data collection for the first category of outcomes, intraoperative performance, will begin preoperatively, with the recording of baseline characteristics: circumference of the thigh in centimeters, baseline hemoglobin levels, and thromboembolism risk evaluation.

Intraoperative data will include: the type of anesthesia, the tourniquet size in centimeters, and whether or not a drain is inserted into the joint. The time of inflation and time of deflation will be noted in order to determine the duration of tourniquet inflation.

Then preincisional blood pressure (BP) will be measured and will continue to be noted every 15 minutes. At the conclusion of the procedure the surgeon will rate intraoperative bloodlessness on a four-point scale: 1-bloodless, 2-nearly bloodless, some bleeding; 3-bloody, tourniquet is no better than not using; or 4-venous tourniquet, tourniquet is making the procedure more difficult. Intraoperative bloodlessness is being used to determine the functionality and effectiveness of the tourniquet, surgical field visualization, and surgical site dryness.

The data collection for the second category of outcomes, post-operative pain and complications, will begin on post-operative day 1 (POD1). Post-operative (post-op) pain will be assessed using a 0-10 pain rating visual analog scale for both the knee and the thigh, and will be measured at POD1, POD2, 2-week followup, 6-week followup, 12-week followup, and 1-year followup. Next, wound healing issues will be assessed at POD1, POD2, 2-week followup, 6-week followup, and 12-week followup. Wound healing issues include blisters, wound drainage, thigh bruising, significant erythema, decreased peripheral pulse, evidence of decreased distal perfusion, or decreased distal sensation.13 Estimated total blood loss will be assessed at POD2 using pre-operative Hgb-level compared to Hgb-level on post-op day 2. The patient's estimated blood volume (EBV) will be calculated using Nadler's formulas for men and women.16

Then Meunier's formula will be used to calculate estimated blood loss.16 If a drain was inserted, then the volume of drainage will be measured at POD1. Finally, aseptic loosing of the implant leading to the need for revision will be assessed at 1-year followup.

The data collection for the third category of outcomes, post-operative function, will begin at POD1. Ability to ambulate will be measured in distance by feet at POD1 and POD2. Furthermore, assessment of any use of assisted device for ambulation (wheelchair, walker, 4-point cane, and 1-point cane) will be done at POD1, POD2, 2-week followup, 6-week followup, 12-week followup and 1-year followup. Quadriceps strength and range of motion (ROM) will be recorded at 2-week followup, 6-week followup, and 12-week followup. Quadriceps strength will be measured on a 5-point scale, where 0 is no movement and 5 is full strength. ROM will be measured in degrees of motion. Next, the necessity of performing a manipulation under anesthesia (MUA) due to limited joint motion will be recorded at 6-week followup and 12-week followup. The type of PT will be recorded at 2-week followup, 6-week followup, and 12-week followup. Types of PT include out-patient PT, home health PT, PT rehabilitation, and skilled nursing facility PT.

Eligibility Criteria:
Inclusion Criteria:

1. 18 - 80 years old
2. primary TKA, not revision

Exclusion Criteria:

1. systolic blood pressure (BP) ≥ 170 mmHg
2. one-staged bilateral TKA or stages less than three months apart
3. history of peripheral vascular disease
4. history of thromboembolism