K.P. is a 71-year-old retired accountant who had a right total knee arthroplasty (TKA) yesterday afternoon. To optimize pain control and promote early mobilization, the hospital follows a multimodal analgesia protocol in the perioperative period for individuals undergoing joint replacements. This protocol involves nonsteroidal anti-inflammatory drugs and acetaminophen, femoral nerve block with bupivacaine, and opiates as needed for additional pain control. On postoperative day one, the physical therapist enters the patient’s room to initiate an evaluation. She finds K.P. seated at the edge of the bed and attempting to stand with the front-wheeled walker. The therapist asks the patient to permit her to assist, but to first allow her to don the knee immobilizer. The patient gets upset and states that he urgently needs to use the bathroom and does not want to waste time. The therapist explains that if he were to attempt standing without the knee immobilizer, he would risk a fall to the floor because of the femoral nerve block that was administered.
Local anesthetics have applications in many different clinical settings. These drugs share a similar mechanism of action and their generic drug names end in “-caine.” These drugs may be applied topically to relieve pain from minor skin injuries or irritations. Local anesthetics such as lidocaine may be infiltrated locally prior to suturing wounds. These drugs are used for inpatient and outpatient day surgeries as the sole form of anesthesia, in combination with general anesthesia, and/or to provide postoperative analgesia. When administered via portable infusion pumps, local anesthetics may be used in ambulatory patients with various chronic pain states. Physical therapists may also directly apply local anesthetics either topically or transdermally for pain management in musculoskeletal disorders (eg, tendonitis, bursitis).
Use of local anesthetics for acute and chronic pain is increasing because they have demonstrated increased pain control and improved functional outcomes under many different clinical scenarios. These drugs are being substituted for opioids in both acute and chronic pain control because local anesthetics have minimal abuse potential. Physical therapists should be aware that patients with postsurgical indwelling spinal catheters delivering a local anesthetic could have temporary motor and sensory loss in the affected extremities. Before attempting rehabilitation interventions, thorough motor and sensory assessment is vital to ensure safe outcomes. Because of the seriousness of systemic adverse effects associated with local anesthetics, therapists should also be alert for signs and symptoms of central nervous system (CNS) effects in patients receiving these drugs.
Local anesthetics block sensory transmission from a specific area of the body to the CNS. Their primary use is to temporarily and reversibly block the sensation of pain, although all peripheral sensations are blocked. Local anesthesia differs from general anesthesia, which is delivered to the systemic circulation in order to depress the CNS. With local anesthesia, the drug is ...