KNEE PAIN
Total knee replacement is one of the most common surgeries performed in orthopedics. Despite the well-documented success of joint replacement in reducing pain and improving function, many patients are hesitant to consider surgery because of concerns over postoperative pain. Uncontrolled pain has many deleterious effects after joint replacement, including patient discomfort, slowed rehabilitation, and perioperative medical complications. Unfortunately, pain after joint replacement has often been inadequately managed in the past. Historically, high-dose opioid medications in the form of patient-controlled analgesia (PCA) have been used to manage postoperative pain. Opioids are associated with many dose-dependent side effects, such as nausea, vomiting, constipation, respiratory depression, urinary retention, and somnolence, which can subsequently hinder recovery.
In response to inadequately managed postoperative pain and the associated side effects of high-dose opioid usage, recent efforts have been focused on the development multi-modal methods for controlling postoperative pain. The goal of multi-modal therapy is to use various interventions that target different steps in the pain pathway. This allows individual agents to act synergistically while requiring lower doses of each drug, which results in better pain relief with fewer side effects. A comprehensive pain management plan utilizes pre-emptive analgesia using preoperative medications, neuraxial anesthesia, regional nerve blocks, periarticular injections, and postoperative oral and intravenous medications.
Preoperative: Patients receive a cocktail of medications with a sip of water approximately one hour prior to surgery for pre-emptive analgesia. This allows therapeutic drug levels upon the completion of surgery, which minimizes pain levels in the recovery unit. A combination of acetaminophen (an antipyretic and analgesic medication), an anti-inflammatory medication, and an opioid medication is provided in the preoperative holding area. In addition, a regional nerve block is often administered. With a nerve block, local anesthetic is injected under ultrasound guidance around peripheral nerves that relay sensation from the operative site. This can improve postoperative pain levels for up to 24 hours.
Intraoperative: Anesthetic pain medications are injected locally into and around the joint and surgical wound.
Postoperative: Again, a combination of medications is used in conjunction for pain relief. Acetaminophen and an anti-inflammatory medication are generally provided around-the-clock. In addition, gapapentinoids are gaining popularity for the treatment of neuropathic pain associated with surgery. Finally, oral and intravenous opioid medications are provided for breakthrough pain as needed.
Techniques for controlling postoperative pain after total knee replacement surgery have advanced significantly in the past decade. Multi-modal pain management protocols have consistently demonstrated improved postoperative pain control while limiting adverse affects associated with high dosages of each individual medication. Furthermore, better pain management results accelerated rehabilitation, shorter hospitalizations, and improved patient satisfaction. Because of this, multi-modal regimens have been steadily replacing high-dose opioid medications in the treatment of postoperative pain.
In summary, recent literature suggests that multi-modal pain protocols have drastically improved patient comfort, satisfaction, and outcome after elective total knee replacement. If you are considering total knee replacement, I encourage you to discuss your postoperative pain management options with your surgeon.
