Implementation of a Pain Management Protocol for Total Knee Arthroplasty

An Analysis of the Functional Benefit, Narcotic Use and Time to Discharge Readiness Following the Implementation of a Comprehensive Pain Management Protocol for Primary Total Knee Arthroplasty

Study question: Is there an ideal combination of intraoperative long acting analgesics (periarticular infiltration (PI), femoral nerve block (FB) and intrathecal opioids (IO)) to optimize post-operative functional recovery, decrease overall narcotic consumption and enable faster 'readiness to discharge' for patients undergoing primary total knee replacement (TKR)?

Our study design is a five-arm double blinded randomized control trial. In order to create a blinded study, each participant will have all three interventions (Femoral Nerve Block (FB), Periarticular Injection (PI) and Intrathecal Opioid (IO)) performed during their visit. Normal saline (NS) will be substituted for opioid or local anesthetic in cases where a control is required.

Specific 5 arms include:

• Using all three anesthetics:

  o PI + FB + IO (arm 1)

• Using a combination of two anesthetics + normal saline substitute for control:

  • NS + FB + IO (arm 2)
  • PI + NS + IO (arm 3)
  • PI + FB + NS (arm 4)

• Control:

  • NS + NS + IO (arm 5)

The control arm would include IO as the sole intervention as this is simply added to the spinal anesthetic used for the surgery itself. It is felt that having a study arm without any long-acting analgesic medication (opioid or local anesthetic) as the "control" arm following a spinal anesthetic would not meet current standard of care and cause harm to the participant

The investigators hypothesize that the combination of three forms of long acting analgesia (PI, FB, IO) will result in the greatest outcomes compared to a combination of any two or control. Our aim is to demonstrate that this optimal analgesic combination will have an additive pain control effect and will minimize side effects thus translating to less acute pain, improve patient mobility, and attaining "readiness to discharge" quicker.

Inclusion Criteria:

• Age 18 years or older
• primary total knee replacement for osteoarthritis
• agrees to a spinal anesthetic for TKR

Exclusion Criteria:

• History of chronic pain or opioid tolerance (individuals requiring equivalent of 1 mg or more intravenous or 3 mg or more oral morphine per hour for greater than 1 month)
• general anesthetic for TKR
• major neurological deficit
• allergy to local anesthetic
• allergy to morphine or hydromorphone, anti-inflammatory, acetaminophen
• renal insufficiency
• liver failure