Case Presentation
Examining the Feasibility of Radiofrequency Treatment for Chronic Knee Pain After Total Knee Arthroplasty Nicole M. Protzman, MS, Jennifer Gyi, DO, Amit D. Malhotra, MD, Jason E. Kooch, DO Recently, investigators began using radiofrequency to manage knee osteoarthritis pain in patients at high risk who cannot undergo surgical intervention. To our knowledge, no study has investigated the use of radiofrequency ablation of the genicular nerves to alleviate chronic knee pain after total knee replacement. A single case is presented here in which genicular nerve ablation successfully improved pain and restored function. We believe that these preliminary results could be used in the development of future prospective cohort studies and randomized controlled trials that focus on the use of radiofrequency ablation to treat persistent knee pain after total knee replacement. PM R 2014;6:373-376
INTRODUCTION Osteoarthritis is a painful and disabling condition that can dramatically influence quality of life. Although some patients can be treated successfully with conservative modalities, other patients with more severe symptoms require surgical intervention. With more than 20 years of documented follow-up, the success of total knee replacement (TKR) has been repeatedly demonstrated [1]. Although most patients demonstrate substantial improvements in pain, function, and overall quality of life after TKR [1], some patients continue to experience persistent pain and/or inadequate knee motion [1,2]. Recently, genicular nerve (GN) ablation has emerged as an alternative intervention for patients at high risk who are unable to undergo surgical intervention. By severing the nerve supply, the transmission of pain signals is disrupted, which purportedly alleviates pain and restores function [3,4]. Given the significant clinical improvements after GN ablation in patients with chronic knee osteoarthritis pain [3,4], this case presentation examines the feasibility of treating chronic knee pain after TKR with radiofrequency (RF) GN ablation.
CASE PRESENTATION In April 2013, a 48-year-old man was referred to the physical medicine office for persistent right anterior, medial, and lateral knee pain. His medical history indicated that, after an injury at work, he experienced persistent right knee pain for several months. Extensive conservative treatments in the form of medication, physical therapy, and injections, including cortisone and viscosupplementation were unsuccessful. In April 2012, the knee demonstrated swelling, with medial and lateral joint line tenderness as well as peripatella tenderness. Trace effusion was noted. Radiographs confirmed no acute fracture, no acute dislocation, and no subluxations. There was bone-on-bone contact in the medial joint space, a narrowed lateral joint space, and bone-on-bone contact in the patellofemoral space. In May 2012, the patient underwent a TKR. One year after surgery, the patient continued to report severe pain. The orthopedic surgeon deemed no loosening of hardware with presumed neuropathic discomfort, possibly secondary to postoperative neuroma formation, at which point, the orthopedic surgeon referred the patient to a physical medicine and rehabilitation physician (J.E.K.) for consideration of right knee RF nerve ablation. At the initial evaluation, palpation of the right knee demonstrated medial and lateral joint line tenderness. The patient’s right knee range of motion demonstrated flexion to 105 PM&R 1934-1482/13/$36.00 Printed in U.S.A.
N.M.P. Department of Clinical Education and Research, Coordinated Health, 2300 Highland Avenue, Bethlehem, PA 18020. Address correspondence to N.M.P.; e-mail: [email protected] Disclosure: nothing to disclose J.G. Department of Physical Medicine and Rehabilitation, Coordinated Health, Bethlehem, PA Disclosure: nothing to disclose A.D.M. Department of Imaging, Coordinated Health, Bethlehem, PA Disclosure: nothing to disclose J.E.K. Department of Physical Medicine and Rehabilitation, Coordinated Health, Bethlehem, PA Disclosure: nothing to disclose Submitted for publication July 17, 2013; accepted October 12, 2013.
ª 2014 by the American Academy of Physical Medicine and Rehabilitation Vol. 6, 373-376, April 2014 http://dx.doi.org/10.1016/j.pmrj.2013.10.003
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RADIOFREQUENCY TREATMENT FOR KNEE PAIN AFTER TKR
Figure 1. (A) Ultrasound-guided identification of the inferomedial genicular nerve; representative longitudinal medial image of the knee at the level of the medial tibial metaphysis, along the distal fibers of the medial collateral ligament (cranial is at the left of the image, and superficial is at the top of the image); the color-flow image helps to elucidate the position of the inferomedial genicular artery, which is located deep to the distal fibers of the medial collateral ligament; the inferior medial genicular nerve (yellow arrow) is the hypoechoic ovoid structure that runs parallel (inferior) to the inferomedial genicular artery. (B) Ultrasound-guided identification of the superomedial genicular nerve; a representative longitudinal image of the knee at the level of the distal medial femoral condyle (cranial is to the left of the image, and caudal is to the right of the image); color-Doppler ultrasound helps to detect the location of the superomedial genicular artery. Inferior to the artery is a tiny hypoechoic structure, noted to be ovoid in the shortaxis images, which corresponds to the accompanying superomedial genicular nerve (yellow arrow); the thick hyperechoic superior fibers of the medial collateral ligament are noted superficial to the artery and the nerve (yellow arrowhead). (C) Ultrasound-guided identification of the superolateral genicular nerve; a representative longitudinal image of the knee at the level of the distal femoral metaphysis (cranial is to the left of the image, and caudal is to the right of the image); color-Doppler ultrasound helps to elucidate the location of the superolateral genicular artery; deep to the artery is a tiny hypoechoic structure, noted to be ovoid on the shortaxis images, which corresponds to the accompanying superolateral genicular nerve (yellow arrow); the thin linear hyperechoic structure superficial to the nerve is the iliotibial band (yellow arrowhead).
and extension to 2 . Given the patient’s symptoms and the failure of all conservative and surgical interventions, the physician suggested a diagnostic nerve block and, depending upon the outcome, RF nerve ablation. The risks, benefits, and alternatives were discussed. Alternative treatments included the use of topical nonsteroidal anti-inflammatory drugs, opioids, and physical therapy. After all questions were answered to his satisfaction, the patient elected to proceed with the trial in an attempt to relieve residual neuropathic pain. One physician performed both procedures (J.E.K.).
fluoroscopic imaging. To anesthetize the GN branches, 1 mL of 1% bupivacaine and 1 mL of 1% lidocaine were injected. By using a visual analogue scale (VAS) from 0 to 10, with 0 representing no pain and 10 representing excruciating pain, the patient’s pain before surgery was a 9. For the 6 hours immediately after the procedure, he reported 100% pain relief. Based on the results of the nerve block, the patient was given the opportunity to proceed with RF GN ablation.
RF GN Ablation Diagnostic Nerve Block The patient’s right inferomedial, superomedial, and superolateral GN branches were identified using ultrasound guidance. Procedure needles were subsequently placed using
The procedure was performed in an outpatient setting. The patient was prepared and draped in a sterile fashion. With the patient in a supine position and the knee slightly flexed, the skin and soft tissues were anesthetized (1 mL of 1%
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Figure 2. Anteroposterior (A) and mediolateral (B) views of the right knee joint under fluoroscopy. After guidance of each of the 3 needles under ultrasound, a frontal spot fluoroscopic image was obtained to document the final needle position using the bony landmarks. The lateral metaphyseal needle is located at the top left of the image. The top right demonstrates the needle tip at the distal femoral metaphysis (superior to the origin of the medial collateral ligament), and the bottom right demonstrates the needle tip at the proximal tibial metaphysis (deep to the distal fibers of the medial collateral ligament).
preservative-free lidocaine). Before needle insertion, bony landmarks were noted using fluoroscopy, and the patient’s right inferomedial, superomedial, and superolateral GN branches were identified under ultrasound guidance. RF needles and probes were advanced to each of the target nerves under ultrasound guidance (Figure 1), and final placement was confirmed by fluoroscopy in both the anteroposterior and lateral views, with reference to bony landmarks (Figure 2). Proximity to the nerve was verified with sensory testing. A total of 2 mL of anesthetic (1 mL of 1% lidocaine and 1 mL of 0.5% bupivacaine) was injected at each target site. An RF current was applied to the 3 sensory nerves. RF was performed at 80 C for 90 seconds using a NT1000 RF Generator (NeuroTherm, Wilmington, MA). With the VAS, the patient’s pain was 0 at 2 weeks and at 3 months. After physical therapy, however, the patient’s reported pain was a 3 of 10. At the 3-month visit, the right knee demonstrated active range of motion of 4 to 108 and passive range of motion of 0 to 112 . The therapist noted gains of strength and range of motion, with a marked
improvement in ambulating upstairs and downstairs without the hand rail. The patient scored a 70.30% on the Knee Injury and Osteoarthritis Outcome Score, with a 71.43% on the symptoms subscale, 69.44% on the pain subscale, 72.06% on the function and daily living subscale, and 62.50% on the quality of life subscale. He did not complete the function in sports and recreational activities subscale.
DISCUSSION Innervation of the knee joint is considerably complex. According to the Hilton law, joints tend to be innervated by articular branches of nerves that supply the muscles that cross the joint [5]. In 1982, Kennedy et al [6] proposed that the articular nerves of the knee form 2 groups, an anterior group and a posterior group. Reportedly, the anterior aspect of the knee is innervated by branches of the femoral, common peroneal, and saphenous nerves, whereas the posterior aspect of the knee is innervated by branches of the obturator, tibial, and sciatic nerves [6,7]. The sciatic nerve extends the
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length of the thigh, and, at the popliteal fossa, it bifurcates into the tibial and common peroneal nerves. The tibial nerve then projects branches that innervate the articular capsule and follow the superior medial genicular and superior lateral vessels [8]. Similarly, the common peroneal nerve has 2 articular branches that innervate the inferolateral aspect of the articular capsule [7,8]. An additional branch of the common peroneal nerve innervates the anterolateral side of the articular capsule and follows the inferior lateral genicular artery [8]. Given the neural intricacy of the knee, RF neurotomy requires identification of anatomic landmarks to locate nerve branches that innervate the knee [4]. The inferomedial, superomedial, and superolateral GN branches have been targeted due to their proximity to bony structures [4]. Therefore, the present report replicated this approach and targeted these specific GNs. By using ultrasound, neurovascular bundles were identified, and, using fluoroscopy, the proximity to the previously reported bony landmarks was confirmed. As opposed to the traditional approach under fluoroscopy, ultrasound allowed the visualization of neurovascular bundles and, presumably, more accurate nerve identification. We found that the use of ultrasound reduced the technical difficulty of locating the nerves, and we believe that this technique can be easily learned. When considering these collective benefits, we advocate the use of ultrasound when performing RF GN ablation. Although this approach is promising, we recognize its potential limitations. The exact pathologic processes that lead to osteoarthritis and the source of pain remain uncertain. Pain is suspected to emanate from the deformation of periarticular tissues, secondary synovitis, and subchondral bone [9]. Although the GNs serve as one of the primary innervating branches, additional innervations exist. Consequently, pain transmission may continue, despite RF ablation. RF has been used to treat a variety of pain conditions. It was originally used to treat trigeminal neuralgia and was expanded to address spinal pain [10]. More recently, investigators used this technique for the management of knee osteoarthritis pain for patients at high risk who could not undergo TKR. These reports have proved promising thus far. In 2011, Ikeuchi et al [3] conducted a controlled trial to examine the efficacy of RF application to sensory nerves. Twelve weeks after the intervention, the patients treated with RF had greater improvements in pain compared with the
RADIOFREQUENCY TREATMENT FOR KNEE PAIN AFTER TKR
control group [3]. Similarly, Choi et al [4] investigated the use of RF treatment to alleviate chronic knee osteoarthritis pain. The randomized controlled trial demonstrated greater improvements in pain, function, and satisfaction for patients treated with RF than for controls [4]. Although the follow-up was limited to 12 weeks, analysis of these findings suggests that RF neurotomy of the GNs has the potential to significantly improve pain, function, and satisfaction [4]. The present study extended RF application from patients at high risk who were unable to undergo TKR to a patient who underwent TKR but continued to present with persistent pain. Also unique to this report, nerve identification was performed under ultrasound guidance. RF neurotomy of the GNs is presumed to eliminate the transmission of sensory signals, with resultant improvements in pain and restoration of function. This case warrants review because it is the first published case of a patient successfully treated with GN RF after TKR. Although the findings of the present study are limited to 1 individual, we believe that these preliminary results could be used to develop prospective, randomized controlled trials that focus on the use of RF ablation to treat persistent knee pain after TKR.
REFERENCES 1. NIH consensus statement on total knee replacement. NIH Consens State Sci Statements 2003;20:1-34. 2. Scranton PE Jr. Management of knee pain and stiffness after total knee arthroplasty. J Arthroplasty 2001;16:428-435. 3. Ikeuchi M, Ushida T, Izumi M, Tani T. Percutaneous radiofrequency treatment for refractory anteromedial pain of osteoarthritic knees. Pain Med 2011;12:546-551. 4. Choi WJ, Hwang SJ, Song SG, et al. Radiofrequency treatment relieves chronic knee osteoarthritis pain: A double-blind randomized controlled trial. Pain 2011;152:481-487. 5. Hilton J. The classic: On rest and pain: Lecture XIV. Clin Orthop Relat Res 2009;467:2208-2214. 6. Kennedy JC, Alexander IJ, Hayes KC. Nerve supply of the human knee and its functional importance. Am J Sports Med 1982;10:329-335. 7. Horner G, Dellon AL. Innervation of the human knee joint and implications for surgery. Clin Orthop Relat Res 1994;301:221-226. 8. Hirasawa Y, Okajima S, Ohta M, Tokioka T. Nerve distribution to the human knee joint: Anatomical and immunohistochemical study. Int Orthop 2000;24:1-4. 9. Ogino S, Sasho T, Suzuki M, et al. Origin of osteoarthritic knee pain: Immunohistochemical analysis of subchondral bone-second report. Trans Orthop Res Soc 2007;23:134. 10. Bogduk N. Pulsed radiofrequency. Pain Med 2006;7:396-407.
Examining the Feasibility of Radiofrequency Treatment for Chronic Knee Pain After Total Knee Arthroplasty Nicole M. Protzman, MS, Jennifer Gyi, DO, Amit D. Malhotra, MD, Jason E. Kooch, DO Recently, investigators began using radiofrequency to manage knee osteoarthritis pain in patients at high risk who cannot undergo surgical intervention. To our knowledge, no study has investigated the use of radiofrequency ablation of the genicular nerves to alleviate chronic knee pain after total knee replacement. A single case is presented here in which genicular nerve ablation successfully improved pain and restored function. We believe that these preliminary results could be used in the development of future prospective cohort studies and randomized controlled trials that focus on the use of radiofrequency ablation to treat persistent knee pain after total knee replacement. PM R 2014;6:373-376
INTRODUCTION Osteoarthritis is a painful and disabling condition that can dramatically influence quality of life. Although some patients can be treated successfully with conservative modalities, other patients with more severe symptoms require surgical intervention. With more than 20 years of documented follow-up, the success of total knee replacement (TKR) has been repeatedly demonstrated [1]. Although most patients demonstrate substantial improvements in pain, function, and overall quality of life after TKR [1], some patients continue to experience persistent pain and/or inadequate knee motion [1,2]. Recently, genicular nerve (GN) ablation has emerged as an alternative intervention for patients at high risk who are unable to undergo surgical intervention. By severing the nerve supply, the transmission of pain signals is disrupted, which purportedly alleviates pain and restores function [3,4]. Given the significant clinical improvements after GN ablation in patients with chronic knee osteoarthritis pain [3,4], this case presentation examines the feasibility of treating chronic knee pain after TKR with radiofrequency (RF) GN ablation.
CASE PRESENTATION In April 2013, a 48-year-old man was referred to the physical medicine office for persistent right anterior, medial, and lateral knee pain. His medical history indicated that, after an injury at work, he experienced persistent right knee pain for several months. Extensive conservative treatments in the form of medication, physical therapy, and injections, including cortisone and viscosupplementation were unsuccessful. In April 2012, the knee demonstrated swelling, with medial and lateral joint line tenderness as well as peripatella tenderness. Trace effusion was noted. Radiographs confirmed no acute fracture, no acute dislocation, and no subluxations. There was bone-on-bone contact in the medial joint space, a narrowed lateral joint space, and bone-on-bone contact in the patellofemoral space. In May 2012, the patient underwent a TKR. One year after surgery, the patient continued to report severe pain. The orthopedic surgeon deemed no loosening of hardware with presumed neuropathic discomfort, possibly secondary to postoperative neuroma formation, at which point, the orthopedic surgeon referred the patient to a physical medicine and rehabilitation physician (J.E.K.) for consideration of right knee RF nerve ablation. At the initial evaluation, palpation of the right knee demonstrated medial and lateral joint line tenderness. The patient’s right knee range of motion demonstrated flexion to 105 PM&R 1934-1482/13/$36.00 Printed in U.S.A.
N.M.P. Department of Clinical Education and Research, Coordinated Health, 2300 Highland Avenue, Bethlehem, PA 18020. Address correspondence to N.M.P.; e-mail: [email protected] Disclosure: nothing to disclose J.G. Department of Physical Medicine and Rehabilitation, Coordinated Health, Bethlehem, PA Disclosure: nothing to disclose A.D.M. Department of Imaging, Coordinated Health, Bethlehem, PA Disclosure: nothing to disclose J.E.K. Department of Physical Medicine and Rehabilitation, Coordinated Health, Bethlehem, PA Disclosure: nothing to disclose Submitted for publication July 17, 2013; accepted October 12, 2013.
ª 2014 by the American Academy of Physical Medicine and Rehabilitation Vol. 6, 373-376, April 2014 http://dx.doi.org/10.1016/j.pmrj.2013.10.003
373
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Protzman et al
RADIOFREQUENCY TREATMENT FOR KNEE PAIN AFTER TKR
Figure 1. (A) Ultrasound-guided identification of the inferomedial genicular nerve; representative longitudinal medial image of the knee at the level of the medial tibial metaphysis, along the distal fibers of the medial collateral ligament (cranial is at the left of the image, and superficial is at the top of the image); the color-flow image helps to elucidate the position of the inferomedial genicular artery, which is located deep to the distal fibers of the medial collateral ligament; the inferior medial genicular nerve (yellow arrow) is the hypoechoic ovoid structure that runs parallel (inferior) to the inferomedial genicular artery. (B) Ultrasound-guided identification of the superomedial genicular nerve; a representative longitudinal image of the knee at the level of the distal medial femoral condyle (cranial is to the left of the image, and caudal is to the right of the image); color-Doppler ultrasound helps to detect the location of the superomedial genicular artery. Inferior to the artery is a tiny hypoechoic structure, noted to be ovoid in the shortaxis images, which corresponds to the accompanying superomedial genicular nerve (yellow arrow); the thick hyperechoic superior fibers of the medial collateral ligament are noted superficial to the artery and the nerve (yellow arrowhead). (C) Ultrasound-guided identification of the superolateral genicular nerve; a representative longitudinal image of the knee at the level of the distal femoral metaphysis (cranial is to the left of the image, and caudal is to the right of the image); color-Doppler ultrasound helps to elucidate the location of the superolateral genicular artery; deep to the artery is a tiny hypoechoic structure, noted to be ovoid on the shortaxis images, which corresponds to the accompanying superolateral genicular nerve (yellow arrow); the thin linear hyperechoic structure superficial to the nerve is the iliotibial band (yellow arrowhead).
and extension to 2 . Given the patient’s symptoms and the failure of all conservative and surgical interventions, the physician suggested a diagnostic nerve block and, depending upon the outcome, RF nerve ablation. The risks, benefits, and alternatives were discussed. Alternative treatments included the use of topical nonsteroidal anti-inflammatory drugs, opioids, and physical therapy. After all questions were answered to his satisfaction, the patient elected to proceed with the trial in an attempt to relieve residual neuropathic pain. One physician performed both procedures (J.E.K.).
fluoroscopic imaging. To anesthetize the GN branches, 1 mL of 1% bupivacaine and 1 mL of 1% lidocaine were injected. By using a visual analogue scale (VAS) from 0 to 10, with 0 representing no pain and 10 representing excruciating pain, the patient’s pain before surgery was a 9. For the 6 hours immediately after the procedure, he reported 100% pain relief. Based on the results of the nerve block, the patient was given the opportunity to proceed with RF GN ablation.
RF GN Ablation Diagnostic Nerve Block The patient’s right inferomedial, superomedial, and superolateral GN branches were identified using ultrasound guidance. Procedure needles were subsequently placed using
The procedure was performed in an outpatient setting. The patient was prepared and draped in a sterile fashion. With the patient in a supine position and the knee slightly flexed, the skin and soft tissues were anesthetized (1 mL of 1%
PM&R
Vol. 6, Iss. 4, 2014
375
Figure 2. Anteroposterior (A) and mediolateral (B) views of the right knee joint under fluoroscopy. After guidance of each of the 3 needles under ultrasound, a frontal spot fluoroscopic image was obtained to document the final needle position using the bony landmarks. The lateral metaphyseal needle is located at the top left of the image. The top right demonstrates the needle tip at the distal femoral metaphysis (superior to the origin of the medial collateral ligament), and the bottom right demonstrates the needle tip at the proximal tibial metaphysis (deep to the distal fibers of the medial collateral ligament).
preservative-free lidocaine). Before needle insertion, bony landmarks were noted using fluoroscopy, and the patient’s right inferomedial, superomedial, and superolateral GN branches were identified under ultrasound guidance. RF needles and probes were advanced to each of the target nerves under ultrasound guidance (Figure 1), and final placement was confirmed by fluoroscopy in both the anteroposterior and lateral views, with reference to bony landmarks (Figure 2). Proximity to the nerve was verified with sensory testing. A total of 2 mL of anesthetic (1 mL of 1% lidocaine and 1 mL of 0.5% bupivacaine) was injected at each target site. An RF current was applied to the 3 sensory nerves. RF was performed at 80 C for 90 seconds using a NT1000 RF Generator (NeuroTherm, Wilmington, MA). With the VAS, the patient’s pain was 0 at 2 weeks and at 3 months. After physical therapy, however, the patient’s reported pain was a 3 of 10. At the 3-month visit, the right knee demonstrated active range of motion of 4 to 108 and passive range of motion of 0 to 112 . The therapist noted gains of strength and range of motion, with a marked
improvement in ambulating upstairs and downstairs without the hand rail. The patient scored a 70.30% on the Knee Injury and Osteoarthritis Outcome Score, with a 71.43% on the symptoms subscale, 69.44% on the pain subscale, 72.06% on the function and daily living subscale, and 62.50% on the quality of life subscale. He did not complete the function in sports and recreational activities subscale.
DISCUSSION Innervation of the knee joint is considerably complex. According to the Hilton law, joints tend to be innervated by articular branches of nerves that supply the muscles that cross the joint [5]. In 1982, Kennedy et al [6] proposed that the articular nerves of the knee form 2 groups, an anterior group and a posterior group. Reportedly, the anterior aspect of the knee is innervated by branches of the femoral, common peroneal, and saphenous nerves, whereas the posterior aspect of the knee is innervated by branches of the obturator, tibial, and sciatic nerves [6,7]. The sciatic nerve extends the
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Protzman et al
length of the thigh, and, at the popliteal fossa, it bifurcates into the tibial and common peroneal nerves. The tibial nerve then projects branches that innervate the articular capsule and follow the superior medial genicular and superior lateral vessels [8]. Similarly, the common peroneal nerve has 2 articular branches that innervate the inferolateral aspect of the articular capsule [7,8]. An additional branch of the common peroneal nerve innervates the anterolateral side of the articular capsule and follows the inferior lateral genicular artery [8]. Given the neural intricacy of the knee, RF neurotomy requires identification of anatomic landmarks to locate nerve branches that innervate the knee [4]. The inferomedial, superomedial, and superolateral GN branches have been targeted due to their proximity to bony structures [4]. Therefore, the present report replicated this approach and targeted these specific GNs. By using ultrasound, neurovascular bundles were identified, and, using fluoroscopy, the proximity to the previously reported bony landmarks was confirmed. As opposed to the traditional approach under fluoroscopy, ultrasound allowed the visualization of neurovascular bundles and, presumably, more accurate nerve identification. We found that the use of ultrasound reduced the technical difficulty of locating the nerves, and we believe that this technique can be easily learned. When considering these collective benefits, we advocate the use of ultrasound when performing RF GN ablation. Although this approach is promising, we recognize its potential limitations. The exact pathologic processes that lead to osteoarthritis and the source of pain remain uncertain. Pain is suspected to emanate from the deformation of periarticular tissues, secondary synovitis, and subchondral bone [9]. Although the GNs serve as one of the primary innervating branches, additional innervations exist. Consequently, pain transmission may continue, despite RF ablation. RF has been used to treat a variety of pain conditions. It was originally used to treat trigeminal neuralgia and was expanded to address spinal pain [10]. More recently, investigators used this technique for the management of knee osteoarthritis pain for patients at high risk who could not undergo TKR. These reports have proved promising thus far. In 2011, Ikeuchi et al [3] conducted a controlled trial to examine the efficacy of RF application to sensory nerves. Twelve weeks after the intervention, the patients treated with RF had greater improvements in pain compared with the
RADIOFREQUENCY TREATMENT FOR KNEE PAIN AFTER TKR
control group [3]. Similarly, Choi et al [4] investigated the use of RF treatment to alleviate chronic knee osteoarthritis pain. The randomized controlled trial demonstrated greater improvements in pain, function, and satisfaction for patients treated with RF than for controls [4]. Although the follow-up was limited to 12 weeks, analysis of these findings suggests that RF neurotomy of the GNs has the potential to significantly improve pain, function, and satisfaction [4]. The present study extended RF application from patients at high risk who were unable to undergo TKR to a patient who underwent TKR but continued to present with persistent pain. Also unique to this report, nerve identification was performed under ultrasound guidance. RF neurotomy of the GNs is presumed to eliminate the transmission of sensory signals, with resultant improvements in pain and restoration of function. This case warrants review because it is the first published case of a patient successfully treated with GN RF after TKR. Although the findings of the present study are limited to 1 individual, we believe that these preliminary results could be used to develop prospective, randomized controlled trials that focus on the use of RF ablation to treat persistent knee pain after TKR.
REFERENCES 1. NIH consensus statement on total knee replacement. NIH Consens State Sci Statements 2003;20:1-34. 2. Scranton PE Jr. Management of knee pain and stiffness after total knee arthroplasty. J Arthroplasty 2001;16:428-435. 3. Ikeuchi M, Ushida T, Izumi M, Tani T. Percutaneous radiofrequency treatment for refractory anteromedial pain of osteoarthritic knees. Pain Med 2011;12:546-551. 4. Choi WJ, Hwang SJ, Song SG, et al. Radiofrequency treatment relieves chronic knee osteoarthritis pain: A double-blind randomized controlled trial. Pain 2011;152:481-487. 5. Hilton J. The classic: On rest and pain: Lecture XIV. Clin Orthop Relat Res 2009;467:2208-2214. 6. Kennedy JC, Alexander IJ, Hayes KC. Nerve supply of the human knee and its functional importance. Am J Sports Med 1982;10:329-335. 7. Horner G, Dellon AL. Innervation of the human knee joint and implications for surgery. Clin Orthop Relat Res 1994;301:221-226. 8. Hirasawa Y, Okajima S, Ohta M, Tokioka T. Nerve distribution to the human knee joint: Anatomical and immunohistochemical study. Int Orthop 2000;24:1-4. 9. Ogino S, Sasho T, Suzuki M, et al. Origin of osteoarthritic knee pain: Immunohistochemical analysis of subchondral bone-second report. Trans Orthop Res Soc 2007;23:134. 10. Bogduk N. Pulsed radiofrequency. Pain Med 2006;7:396-407.
