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NCT Number: NCT07747116

Knee Positioning After Total Knee Replacement

Many total knee replacements are performed each year, but there is no clear recommendation regarding knee positioning following this surgery. While the surgical knee is usually positioned in a straight position immediately after surgery, there may be benefits of positioning it in a partially bent position. A trial will compare the outcomes of two groups of patients: a) those whose knees are positioned in a partially bent position for a few hours after surgery and b) those who receive usual care where the knee is most likely positioned in a straight position. The investigators are looking to see whether knee motion and pain differ for patients in the two groups.

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Key information

Conditions

Knee Arthroplasty

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

About this study

This parallel two-arm randomized controlled trial will compare outcomes for knee flexion versus usual care in the immediate postoperative period after total knee arthroplasty. Patients who are scheduled for elective primary unilateral total knee arthroplasty will be recruited from an academic health system, screened for inclusion/exclusion criteria, and enrolled. The experimental group will have their surgical knee positioned in approximately 60° of flexion for 2-4 hours after surgery. The control group will receive usual care, where the knee will generally be positioned in extension. Other than the study intervention, both groups will receive standard perioperative, intraoperative, and postoperative care as determined by their treating clinical team. The co-primary endpoints are 6-week knee passive total arc of motion and 7-day maximum pain intensity. Secondary outcomes will be assessed throughout the 12 months after surgery and will include knee motion and pain intensity at other time points; oral opioid consumption; patient-reported questionnaires of knee health, quality of life, and satisfaction; healthcare utilization; and complications. Adverse events will also be monitored for the 12 months after surgery. Outcomes will be assessed via phone or electronic surveys; routine care visits at 2.5 weeks, 6 weeks, 3 months, 6 months, and 12 months after surgery; and chart review.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Provision of signed and dated informed consent form
  • Stated willingness to comply with all study procedures and availability for the duration of the study
  • Males and females; Age >18 years
  • Scheduled for elective primary unilateral total knee arthroplasty
  • The planned arthroplasty is secondary to physician-confirmed diagnosis of knee osteoarthritis
  • English- or Spanish-speaking

Exclusion criteria

  • Patients with a history of chronic opioid use or chronic pain disorders
  • Patients with a history of bleeding disorders/coagulopathy
  • Patients receiving a total knee replacement secondary to trauma, avascular necrosis, tumor, or Charcot arthropathy
  • Patients scheduled to undergo multiple procedures simultaneously
  • Patients with cognitive impairment or inability to consent independently

Treatment and study plan

Knee Flexion

Other

Participants will receive knee flexion postoperatively following primary total knee arthroplasty. The surgical knee will positioned at approximately 60° flexion using an abduction pillow as a jig underneath the knee during the immediate postoperative recovery period. Positioning will occur following surgery while the participant is still in the operating room. This is a soft construct and a noninvasive intervention. A goniometer will be used to approximate 60° of flexion as closely as possible. It is expected that the knee will be positioned for 2-4 postoperative hours until a physical therapist comes to mobilize the patient. However, the duration may vary because of the pragmatic context. There is no minimum or maximum positioning time that would make the intervention duration ineligible.

Standard care

Procedure

Participants in this arm will receive usual care. No specific attention will be placed to knee positioning in the immediate period after surgery. However, the current usual practice in the health system is that the knee is positioned in extension.

Primary outcomes

  1. Knee Passive Total Arc of Motion

    Time frame: At 6 weeks after surgery

    Passive total arc of motion will be evaluated through goniometric assessment of maximal passive knee flexion and passive knee extension. Both measures will be recorded, but a single endpoint will be derived by subtracting available extension from available flexion.

  2. Maximum Pain Intensity

    Time frame: At 7 days after surgery

    Pain intensity will be evaluated via the patient-reported Numeric Rating Scale (NRS) for pain. The rating is from 0 to 10, with a higher score indicating worse pain. The worst (i.e., maximum) pain intensity will be used.

Secondary outcomes

  1. Knee Passive Total Arc of Motion

    Time frame: At 2.5 weeks, 3 months, 6 months, and 12 months after surgery

    Passive total arc of motion will be evaluated through goniometric assessment of maximal passive knee flexion and passive knee extension. Both measures will be recorded, but a single endpoint will be derived by subtracting available extension from available flexion.

  2. Maximum Pain Intensity

    Time frame: At 0 days, 1 day, 2 days, 3 days, 10 days, 14 days, 2.5 weeks, 6 weeks, 3 months, 6 months, and 12 months after surgery

    Pain intensity will be evaluated via the patient-reported Numeric Rating Scale (NRS) for pain. The rating is from 0 to 10, with a higher score indicating worse pain. The worst (i.e., maximum) pain intensity will be used.

  3. Total Opioid Consumption

    Time frame: Postoperative days 0 through 14

    Consumption of opioids standardized in oral morphine milligram equivalents based on medical records for in-hospital administration, prescriptions, and patient report for at-home consumption. Consumption will be summed across days, with higher numbers indicating greater opioid consumption.

  4. Knee Injury and Osteoarthritis Outcome Score for Joint Replacement

    Time frame: At 6 weeks, 3 months, 6 months, and 12 months after surgery

    The Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS, JR) is a patient-reported measure of knee health (i.e., pain and function). Scores range from 0 to 100, with higher scores indicating better health.

  5. Veterans RAND 12-item Health Survey

    Time frame: At 6 weeks, 3 months, 6 months, and 12 months after surgery

    The Veterans RAND 12-item Health Survey (VR-12) is a patient-reported measure of global physical and mental health. It provides a physical component summary score and a mental component summary score. These are T-scores with a mean of 50, and higher scores indicate better health.

  6. Goodman Satisfaction Score

    Time frame: 12 months after surgery

    The Goodman Satisfaction Score assesses patient satisfaction with total hip or knee arthroplasty outcomes. Scores range from 0 to 100, with higher scores indicating greater satisfaction.

  7. Length of Hospital Stay

    Time frame: Through hospital discharge, average of 1 day, up to 30 days after surgery

    Number of days the patient stays in the hospital after the index surgery. This information will be extracted from the medical record.

  8. Percentage of Participants with an Emergency Department Visit

    Time frame: Within 7 days, 30 days, and 90 days after surgery

    Percentage of participants with an all-cause emergency department visit after surgery. This information will be extracted from the medical record, with supplementation by participant queries during the postoperative visit after the respective timepoint.

  9. Percentage of Participants with a Hospital Readmission

    Time frame: Within 30 days and 90 days after surgery

    Percentage of participants with an all-cause hospital readmission after surgery. This information will be extracted from the medical record, with supplementation by participant queries during the postoperative visit after the respective timepoint.

  10. Percentage of Participants with Deep Vein Thrombosis

    Time frame: Within 30 days and 90 days after surgery

    Percentage of participants who have deep vein thrombosis after surgery.

  11. Percentage of Participants with a Pulmonary Embolism

    Time frame: Within 30 days and 90 days after surgery

    Percentage of participants who have a pulmonary embolism after surgery. This information will be extracted from the medical record, with supplementation by participant queries during the postoperative visit after the respective timepoint.

  12. Percentage of Participants with a Venous Thromboembolism

    Time frame: Within 30 days and 90 days after surgery

    Percentage of participants who have a venous thromboembolism after surgery. This information will be extracted from the medical record, with supplementation by participant queries during the postoperative visit after the respective timepoint.

  13. Percentage of Participants with a Coronary Event

    Time frame: Within 30 days and 90 days after surgery

    Percentage of participants who have a myocardial infarction or other coronary event after surgery. This information will be extracted from the medical record, with supplementation by participant queries during the postoperative visit after the respective timepoint.

  14. Percentage of Participants with a Stroke

    Time frame: Within 30 days and 90 days after surgery

    Percentage of participants who have a stroke after surgery. This information will be extracted from the medical record, with supplementation by participant queries during the postoperative visit after the respective timepoint.

  15. Percentage of Participants with a Blood Transfusion

    Time frame: Within 30 days after surgery

    Percentage of participants who receive a blood transfusion after surgery. This information will be extracted from the medical record, with supplementation by participant queries during the postoperative visit after the respective timepoint.

  16. Percentage of Participants with a Wound Dehiscence

    Time frame: Within 30 days and 90 days after surgery

    Percentage of participants who have a wound dehiscence after surgery. This information will be extracted from the medical record, with supplementation by participant queries during the postoperative visit after the respective timepoint.

  17. Percentage of Participants with a Mechanical Complication

    Time frame: Within 30 days and 90 days after surgery

    Percentage of participants who have a mechanical complication after surgery. This information will be extracted from the medical record, with supplementation by participant queries during the postoperative visit after the respective timepoint.

  18. Percentage of Participants with a Manipulation under Anesthesia

    Time frame: Within 12 months after surgery

    Percentage of participants who undergo a manipulation under anesthesia after surgery. This information will be extracted from the medical record, with supplementation by participant queries during the postoperative visit after the respective timepoint.

  19. Percentage of Participants with a Knee Revision Surgery

    Time frame: Within 12 months after surgery

    Percentage of participants who undergo a knee revision surgery after the index surgery. This information will be extracted from the medical record, with supplementation by participant queries during the postoperative visit after the respective timepoint.

Study contacts

Contact information is provided by the study sponsor or research team.

Brocha Stern

CONTACT

[email protected]

212-659-9650

Sponsors and collaborators

Lead sponsor

Icahn School of Medicine at Mount Sinai

Other

Registry information

Official study title

The Effects of Postoperative Positioning in Knee Flexion Versus Usual Care After Total Knee Arthroplasty: A Randomized Controlled Trial

Important dates

Study start
2026
Primary completion
2028
Study completion
2029
First posted
Aug 5, 2026
Registry last updated
Aug 5, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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