Periarticular Regional Analgesia in Total Knee Arthroplasty




Perioperative pain control after total knee arthroplasty may be insufficient, resulting in insomnia, antalgic ambulation, and difficulty with rehabilitation. Current strategies, including the use of femoral nerve catheters, may control pain but have been associated with falls, motor blockade, and quadriceps inhibition. Periarticular infiltration using the appropriate technique and knowledge of intraarticular knee anatomy may increase pain control and maximize rehabilitation.


Key points








  • Postoperative control after total knee arthroplasty may be insufficient, resulting in insomnia, antalgic ambulation, and difficulty with rehabilitation.



  • Current strategies, including the use of femoral nerve catheters, may control pain but have been associated with falls, motor blockade, and quadriceps inhibition.



  • Periarticular infiltration using the appropriate technique and knowledge of intraarticular knee anatomy may increase pain control and maximize rehabilitation.






Introduction


Total knee arthroplasty (TKA) is a frequently performed procedure, and its incidence is expected to increase 673% to 3.48 million procedures annually by 2030. Current literature confirms that TKA is an effective treatment for osteoarthritis with excellent outcomes. Despite these results, current postoperative pain management may be insufficient and prevent patients from sleeping, ambulating, and participating in physical therapy. Numerous strategies have been devised to control postoperative pain and reduce opioid consumption, including neuraxial anesthesia and peripheral nerve blocks. Continuous femoral nerve blockade, in particular, is associated with a 1.0% to 2.5% incidence of muscle weakness, nerve damage, and local infection, with 57% of catheters colonized at 48 hours.


In addition to peripheral nerve blocks, parenteral narcotics continue to be a mainstay of postoperative pain management despite significant side effects. Oderda and colleagues demonstrated that opioid-related adverse drug events after surgery were associated with significantly increased length of stay and hospitalization costs. With the goal of decreasing these adverse drug events, multimodal pain pathways have been developed to block pain at its source. Furthermore, a successful multimodal pathway should control pain but also maximize muscle control, promote rehabilitation, and decrease venous stasis. Periarticular injection (PAI), as an adjunct to multimodal pain management pathways, accomplishes these goals.


Evidence from the literature supports the use of PAI. In a study by Vendittoli and colleagues, morphine consumption was lower in the PAI group compared with the control group for up to 40 hours postoperatively. Other authors have compared different PAI protocols and reported that these are associated with lower narcotic consumption and pain scores compared with use of a femoral nerve block. In a recent prospective randomized trial by Chaumeron and colleagues, PAI provided equivalent pain control for up to 120 hours without the 37% incidence of motor blockade experienced by the group receiving a femoral nerve block. Patients who received PAI had an increased capacity to perform a straight leg raise, better active knee extension, and an increased ability to ambulate than those receiving a femoral nerve block. This article reviews the relevant neuroanatomy of the knee, with specific attention to the areas that are the most sensitive and should be infiltrated with an anesthetic.




Introduction


Total knee arthroplasty (TKA) is a frequently performed procedure, and its incidence is expected to increase 673% to 3.48 million procedures annually by 2030. Current literature confirms that TKA is an effective treatment for osteoarthritis with excellent outcomes. Despite these results, current postoperative pain management may be insufficient and prevent patients from sleeping, ambulating, and participating in physical therapy. Numerous strategies have been devised to control postoperative pain and reduce opioid consumption, including neuraxial anesthesia and peripheral nerve blocks. Continuous femoral nerve blockade, in particular, is associated with a 1.0% to 2.5% incidence of muscle weakness, nerve damage, and local infection, with 57% of catheters colonized at 48 hours.


In addition to peripheral nerve blocks, parenteral narcotics continue to be a mainstay of postoperative pain management despite significant side effects. Oderda and colleagues demonstrated that opioid-related adverse drug events after surgery were associated with significantly increased length of stay and hospitalization costs. With the goal of decreasing these adverse drug events, multimodal pain pathways have been developed to block pain at its source. Furthermore, a successful multimodal pathway should control pain but also maximize muscle control, promote rehabilitation, and decrease venous stasis. Periarticular injection (PAI), as an adjunct to multimodal pain management pathways, accomplishes these goals.


Evidence from the literature supports the use of PAI. In a study by Vendittoli and colleagues, morphine consumption was lower in the PAI group compared with the control group for up to 40 hours postoperatively. Other authors have compared different PAI protocols and reported that these are associated with lower narcotic consumption and pain scores compared with use of a femoral nerve block. In a recent prospective randomized trial by Chaumeron and colleagues, PAI provided equivalent pain control for up to 120 hours without the 37% incidence of motor blockade experienced by the group receiving a femoral nerve block. Patients who received PAI had an increased capacity to perform a straight leg raise, better active knee extension, and an increased ability to ambulate than those receiving a femoral nerve block. This article reviews the relevant neuroanatomy of the knee, with specific attention to the areas that are the most sensitive and should be infiltrated with an anesthetic.




Methods


The current available literature on knee neuroanatomy, pain generators, and concentrations of mechanoreceptors were reviewed. The databases searched include MEDLINE, MEDLINE In-Process, EMBASE, BIOSIS, ClinicalTrials.gov , and Cochrane Database of Systematic Reviews. Full text searching of key surgical journals was also performed. Searches were not restricted by study design, publication year, or language, and conference proceedings and abstracts were included in the search. Reference lists of all included studies were scanned to identify additional relevant studies. Search terms included “knee innervation,” “pain control,” ”knee mechanoreceptor,” “sartorial nerve,” “saphenous nerve,” “common peroneal nerve,” and “tibial nerve.” Studies were excluded if they did not provide pertinent information on human knee innervation or were not published in English. The search produced 56 articles, of which 15 met inclusion criteria. This article summarizes human knee innervation and relevant areas of increased mechanoreceptors.




Neuroanatomy


The degree to which the intraarticular components of the knee generate neurosensory signals that reach the spinal, cerebellar, and higher central nervous system levels is variable. These signals ultimately result in conscious perception. Biedert and colleagues performed a histologic examination of free nerve endings in the human knee to describe which intraarticular areas contain increased nerve endings and mechanoreceptors. They found that the retinacula, patellar ligament, pes anserinus, and ligaments of Wrisberg and Humphry had the greatest number of free nerve endings, whereas the lowest number was found in the anterior cruciate ligament (ACL). In a correlate study by Dye and colleagues, conscious patients underwent knee arthroscopy without anesthesia and were able to identify which areas of the knee were more painful on arthroscopic palpation. The following 8 knee regions have been identified as having increased neurosensory perception and an elevated concentration of mechanoreceptors: (1) suprapatellar pouch and quadriceps tendon, (2) medial retinaculum, (3) patellar tendon and fat pad, (4) medial collateral ligament and medial meniscus capsular attachment, (5) posterior cruciate ligament (PCL) tibial attachment, (6) ACL femoral attachment, (7) lateral collateral ligament and lateral meniscus capsular attachment, and (8) lateral retinaculum ( Fig. 1 ). The nerve contributions to each zone are discussed in the following sections.




Fig. 1


The 8 regions of the knee ( red markings ) that have increased pain receptors.

( From Best Infiltration Practices Local Analgesia Infiltration Techniques – Hip & Knee Arthroplasty. Copyright © 2014. All rights reserved GuidelineCentral.com , with permission from International Guidelines Center ( guidelinecentral.com ); and Courtesy of Erin Daniel, with permission.)


Zone 1: Suprapatellar Pouch/Quadriceps Tendon


The saphenous nerve is the longest and largest branch of the femoral nerve. It is a pure sensory nerve that supplies innervation to the anteromedial aspect of the lower leg from the knee to the foot. During its course in the thigh, the nerve runs in the adductor canal (Hunter canal) and migrates along with the sartorius muscle. Within the adductor canal, the saphenous nerve lays anteromedial to the femoral artery and vein. In addition to the saphenous nerve and the femoral vessels, the canal also includes the nerve to the vastus medialis and other motor branches of the femoral nerve. The minor branches of the femoral nerve, including the nerve to the vastus medialis and the nerve to the vastus lateralis, supply innervation to the quadriceps tendon. These nerves are also distributed to the articular capsule and the suprapatellar pouch.


Zone 2: Medial Retinaculum


The medial retinacular nerve, the terminal branch of the nerve to the vastus medialis, provides innervation to the medial retinaculum. It usually travels in the substance of the muscle, and enters the joint capsule to innervate medial articular structures, also sending a branch to the medial patella.


Zone 3: Patellar Tendon and Fat Pad


The infrapatellar fat pad is a densely innervated structure, receiving nerve contribution from the saphenous, tibial, and common peroneal nerves. The nerve to the vastus medialis and the saphenous nerve provide medial sensory innervation to the fat pad. The common peroneal nerve projects the recurrent articular branch, and the tibial nerve projects the posterior articular branch to provide the lateral sensory innervation.


Zone 4: Medial Collateral Ligament and Medial Meniscus Capsular Attachment


The main branch of the saphenous nerve, as it runs down the anterolateral edge of the sartorius, supplies innervation to the medial and anteroinferior side of the knee. It also supplies a wide area covering the articular capsule, medial collateral ligament, and meniscal capsular attachment.


Zone 5: Posterior Cruciate Ligament Tibial Attachment/Zone 6: Anterior Cruciate Ligament Femoral Attachment


Formed by the L4-S3 nerve roots, the sciatic nerve is the largest nerve in the body. The peroneal and tibial divisions of the sciatic nerve physically split at or above the popliteal fossa to form the common peroneal nerve and the tibial nerve. The tibial nerve is the medial and largest terminal branch of the sciatic nerve. The tibial nerve branches off from the sciatic nerve at the apex of the popliteal fossa, which looks like a diamond-shaped fatty space bordered by the biceps femoris and the semimembranosus muscles superiorly and the 2 heads of the gastrocnemius muscle inferiorly. During its vertical course in the popliteal fossa, the nerve is virtually median, typically just posterior to the popliteal vein, whereas the popliteal artery is anterior to the vein. Collaterals of the tibial nerve in the knee region include the posterior articular branch, which supplies sensory innervation to the ACL and PCL.


Zone 7: Lateral Collateral Ligament and Lateral Meniscus Capsular Attachment/Zone 8: Lateral Retinaculum


The tibial nerve projects articular branches at the popliteal fossa, innervating the posterolateral capsule. The common peroneal nerve projects articular branches as it runs down medially along the long head of the biceps femoris. These branches run toward the deep part of the long head of the biceps femoris and innervate the posterior and lateral side of the articular capsule. The common peroneal nerve also projects an articular branch as it runs down to the origin of the lateral head of the gastrocnemius and extends to the head of the fibula. This branch runs with the inferolateral popliteal vessels and innervates the anterolateral side of the lateral retinaculum, lateral cruciate ligament, and the lateral meniscus remnant. There is also some contribution to the patellar tendon and infrapatellar fat pad.

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Oct 6, 2017 | Posted by in ORTHOPEDIC | Comments Off on Periarticular Regional Analgesia in Total Knee Arthroplasty

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