Total knee arthroplasty (TKA), also known as total knee replacement, is one of the most frequently performed orthopedic procedures. It can provide pain relief, improve function, and increase quality of life for patients. However, it is a major operation involving significant tissue trauma and pain. Comprehensive pain management is essential for positive outcomes and proper recovery. In particular, a peripheral nerve block is a key component of total knee replacement surgeries.

As of 2010, over 600,000 TKAs were being performed annually in the United States and were becoming increasingly common. Among older patients in the United States, the per capita number of primary TKAs doubled from 1991 to 2010 (from 31 to 62 per 10,000 annually). The number of TKAs performed annually in the United States is expected to increase in volume by 143 percent by 2050 compared with 2012.

TKA involves removing the damaged articular surfaces of the knee and replacing them with metal and polyethylene prosthetic components. Despite its advantages, TKA is typically elective and should be considered only after exhausting nonsurgical options and thoroughly discussing the risks, benefits, and alternatives. Generally, TKA is performed to address joint cartilage destruction caused by conditions such as osteoarthritis, rheumatoid arthritis, post-traumatic degenerative joint disease, or osteonecrosis, all of which can lead to pain and impaired knee joint function.

The aim of pain management following TKA is to provide effective analgesia, enabling immediate rehabilitation and early mobilization. Modern multimodal strategies for postoperative pain control after TKA have reduced the necessity for intravenous opioids. These strategies may involve the use of acetaminophen, nonsteroidal anti-inflammatory drugs (NSAIDs), gabapentinoids, regional anesthesia techniques, and periarticular local anesthetic infiltration.

Single-injection and continuous peripheral nerve blocks are commonly employed for postoperative pain relief following TKA. Numerous studies have demonstrated decreased perioperative complications and improved patient satisfaction when using peripheral nerve blocks compared to traditional opioid therapy.

The knee receives sensory innervation from the femoral, sciatic, and obturator nerves, providing several potential targets for a nerve block for total knee replacement. A common approach is to perform a single block of the femoral nerve or its distal sensory branches to achieve partial, yet generally sufficient, analgesia.

The femoral nerve block (FNB) numbs the front part of the upper leg and inner areas of the lower leg. It can be given as a single injection or through a catheter for continuous pain relief. Research suggests that the pain-relieving effects typically last 12-24 hours after a single injection, with some studies indicating effects may last up to 48 hours. Szcuzukowski Jr. et al. found that patients who received a single injection of bupivacaine with epinephrine had significantly reduced morphine consumption, sedation, and pain scores compared to those without an FNB. Ilfeld et al. reported that continuous femoral nerve blockade (CFNB) shortened the time to discharge for patients undergoing TKA. Multiple studies have consistently supported these findings, showing that FNB provides better pain management, speeds up functional recovery, and shortens hospital stays, all with a more favorable side effect profile than epidural techniques.

While FNB is considered safe overall, there are some reported adverse effects. Notably, approximately 2-2.7% of patients receiving FNB experience quadriceps weakness and femoral nerve palsy, which can result in falls or prolonged difficulty with mobility. Other documented side effects include nausea, vomiting, hematoma formation, catheter site infection, and blockade failure. Anesthesia providers and surgeons may prefer other nerve block options for total knee replacement for these reasons.

In conclusion, TKA offers significant pain relief and improved function for patients with joint cartilage destruction but requires careful consideration due to the need for extensive postoperative pain management, including the use of FNB. While FNB can provide effective pain relief, it is not without risks, as some patients may experience adverse effects. Other nerve block options for total knee replacement may be worth exploring.

References

Hasegawa M, Singh D, Urits I, Pi M, Nakasone C, Viswanath O, Kaye AD. Review on Nerve Blocks Utilized for Perioperative Total Knee Arthroplasty Analgesia. Orthop Rev (Pavia). 2022 Aug 5;14(3):37405. doi: 10.52965/001c.37405.

Ilfeld BM, Le LT, Meyer RS, Mariano ER, Vandenborne K, Duncan PW, Sessler DI, Enneking FK, Shuster JJ, Theriaque DW, Berry LF, Spadoni EH, Gearen PF. Ambulatory continuous femoral nerve blocks decrease time to discharge readiness after tricompartment total knee arthroplasty: a randomized, triple-masked, placebo-controlled study. Anesthesiology. 2008 Apr;108(4):703-13. doi: 10.1097/ALN.0b013e318167af46.

Szczukowski MJ Jr, Hines JA, Snell JA, Sisca TS. Femoral nerve block for total knee arthroplasty patients: a method to control postoperative pain. J Arthroplasty. 2004 Sep;19(6):720-5. doi: 10.1016/j.arth.2004.02.043.

Hebl JR, Kopp SL, Ali MH, Horlocker TT, Dilger JA, Lennon RL, Williams BA, Hanssen AD, Pagnano MW. A comprehensive anesthesia protocol that emphasizes peripheral nerve blockade for total knee and total hip arthroplasty. J Bone Joint Surg Am. 2005;87 Suppl 2:63-70. doi: 10.2106/JBJS.E.00491.

Cram P, Lu X, Kates SL, Singh JA, Li Y, Wolf BR. Total knee arthroplasty volume, utilization, and outcomes among Medicare beneficiaries, 1991-2010. JAMA. 2012 Sep 26;308(12):1227-36. doi: 10.1001/2012.jama.11153.

Inacio MCS, Paxton EW, Graves SE, Namba RS, Nemes S. Projected increase in total knee arthroplasty in the United States – an alternative projection model. Osteoarthritis Cartilage. 2017 Nov;25(11):1797-1803. doi: 10.1016/j.joca.2017.07.022.

Sloan M, Premkumar A, Sheth NP. Projected Volume of Primary Total Joint Arthroplasty in the U.S., 2014 to 2030. J Bone Joint Surg Am. 2018 Sep 5;100(17):1455-1460. doi: 10.2106/JBJS.17.01617.