Genicular nerve block for emergency department patient: a successful management of subacute osteoarthritic knee pain.

The genicular nerve block (GNB) performed under ultrasound is a common procedure in the perioperative and outpatient setting for the treatment of surgical knee pain and osteoarthritis. It provides motor-sparing analgesia to the knee, making it a potential alternative to other modes of pain management in the emergency department (ED). We present an elderly woman with acute-on-chronic osteoarthritic knee pain which was relieved for a week after a GNB during her ED visit. In patients with knee pain, the ultrasound guided GNB has the potential to provide short-term analgesia for patients with pain refractory to other modes of analgesia. The GNB shows promise as a reliable contribution to a multimodal approach to pain management in the ED setting.

Radiofrequency Ablation of the Infrapatellar Branch of the Saphenous Nerve for the Treatment of Chronic Anterior Inferomedial Knee Pain.

INTRO: Genicular nerve radiofrequency ablation (GNRFA) is an effective treatment for chronic knee pain related to osteoarthritis. It is often utilized when conservative management has failed and patients wish to avoid arthroplasty, are poor surgical candidates due to comorbid medical conditions, or in those suffering from persistent pain after arthroplasty. The classic targets for GNRFA include the superior lateral genicular nerve, superior medial genicular nerve, and inferior medial genicular nerve but multiple anatomic studies have demonstrated additional sensory innervation to the knee. OBJECTIVE: In this research article, we propose an image-guided technique that can safely target the infrapatellar branch of the saphenous nerve which also provides sensory innervation to the anterior capsule. PROPOSAL: The proposed technique includes variations for conventional bipolar radiofrequency ablation, cooled radiofrequency ablation, dual-tined bipolar radiofrequency ablation, and monopolar radiofrequency ablation using a long axis approach. The described technique is based on updated anatomic studies and takes into account safety concerns such as thermal risk to the skin and/or pes anserine tendons and breaching of the synovial cavity. CONCLUSION: Future clinical research should be performed to confirm the safety and effectiveness of this specific approach.

A case report of ultrasound-guided knee nerve pulse radiofrequency combined with platelet-rich plasma in the treatment of knee osteoarthritis.

RATIONABLE: Knee osteoarthritis (KOA) is a disease characterized by noninflammatory degenerative changes of articular cartilage. The main clinical manifestations are joint pain and stiffness. Pulsed radiofrequency (PRF) is thought to treat pain by destroying nerve tissue and changing the physical characteristics of nerve tissue membrane. PATIENT CONCERNS: The patients presents with joint pain and tenderness. Touching around the knee joint will induce pain and joint stiffness when the hand is pressed hard. INTERVENTIONS: Four patients with knee osteoarthritis underwent pulsed radiofrequency thermocoagulation in the knee joint cavity under ultrasound guidance and injected 2 mL of 10 mg/mL platelet-rich plasma into the joint cavity once a week for a total of 4 times. Record the patient's Visual Analogue Scale (VAS) score and the degree of knee movement limitation before treatment, 1, 3, and 6 months after treatment. DIAGNOSES: Four patients with knee osteoarthritis. OUTCOMES: After treatment, the patient's VAS score improved, and the knee joint mobility function recovered well. Ultrasound-guided knee nerve pulse radiofrequency combined with intra-articular injection of platelet-rich plasma can effectively improve the knee joint function and reduce the pain of the patient. The clinical effect is significant, and it is worthy of clinical application.

Anatomical Study of the Infrapatellar Branch of the Saphenous Nerve in Humans / Estudo anatômico do ramo infrapatelar do nervo safeno em humanos

Abstract Objective To perform an anatomical study of the location of the infrapatellar branch of the saphenous nerve in relation to the structures of the knee. Methods An anatomical study was performed by dissection of 18 humans knees (9 right and 9 left knees). After exposure of the infrapatellar branch and its direct and indirect branches, they were then measured. We adopted a quadrant in the medial region of the knee delimited by two transversal planes as a parameter of the study. Results In 17 of the 18 knees (94.4%) studied, a single infrapatellar branch was observed. The infrapatellar branch emerged as fibers of the womb of the sartorius muscle in 17 of the 18 knees (94.4%). In relation to the branch, we observed that in 100% of the knees the infrapatellar branch had at least one primary branch, resulting in a superior branch and an inferior branch. In 9 limbs (50% of the cases) this branch occurred outside the proposed quadrant, and, in the remaining limbs, it occurred within the quadrant. Conclusion The infrapatellar saphenous nerve branch was found in all dissected knees, and, in 94.4% of the cases, it was of the penetrating type; in 100% of the cases, it originated two primary direct branches. The direct and indirect branches presented great variability regarding their path.

Resumo Objetivo Realizar um estudo anatômico da localização do ramo infrapatelar do nervo safeno em relação às estruturas do joelho. Métodos Estudo anatômico realizado por meio de dissecação de 18 joelhos (9 direitos e 9 esquerdos). Após a exposição do ramo infrapatelar e de seus ramos diretos e indiretos, seguiram-se as medidas deles. Como parâmetro do estudo, adotamos um quadrante na região medial do joelho delimitado por dois planos transversais. Resultados Em 17 dos 18 joelhos estudados (94,4%), observou-se um único ramo infrapatelar. O ramo infrapatelar emergia por entre as fibras do ventre do músculo sartório em 17 dos 18 joelhos (94,4%). Em relação à ramificação, observamos que em 100% dos joelhos o ramo infrapatelar apresentava pelo menos uma ramificação primária, resultando num ramo superior e em outro inferior. Em 9 membros (50% dos casos), esta ramificação ocorria fora do quadrante proposto, e, no restante, dentro do quadrante. Conclusão O ramo infrapatelar do nervo safeno foi encontrado em todos os joelhos dissecados e, em 94,4% dos casos, ele era do tipo penetrante; em 100% dos casos, ele originava 2 ramos diretos primários. Seus ramos diretos e indiretos apresentaram grande variabilidade quanto ao trajeto.

Functions necessary for gait independence in patients with stroke: A study using decision tree.

BACKGROUND: Little is known about the existence and impact of interactions among multiple impairments to gait independence. The purpose of this study is to reveal the interaction of physical functions and its impact on gait independence in stroke patients. METHODS: This retrospective study included 108 subacute stroke patients. We conducted a decision tree analysis to examine the existence of interactions in relation to gait independence among the gross motor function of lower limb, knee extension strength, sensory function, and trunk function. Further, we confirmed the existence and impact of interaction detected via the decision tree after adjusting for the effects of confounding factors using logistic regression. RESULTS: The knee extension strength and proprioception on the affected side were selected in the first and second level of the decision tree. In addition, the knee extension strength was selected in the third level. The interaction of the knee extension strength and proprioception on the affected side was significantly associated with gait independence, both before and after adjusting for age, visuospatial perception, and cognitive functions. CONCLUSIONS: Our results suggest that the interaction of the knee extension strength and proprioception on the affected side is strongly associated with gait independence in stroke patients.

Proclaim™ DRG Neurostimulator System for the management of chronic, intractable pain.

Chronic pain is consistently listed as one of the most costly and disabling health problems worldwide. In an effort to treat these suffering individuals, significant amounts of time and energy have been devoted to discover safe and effective pain relieving treatments. Dorsal root ganglion stimulation is the newest treatment modality to be created for chronic intractable pain. In this manuscript, we review the history and development, published research and safety profile of the Proclaim™ DRG Neurostimulator System (Abbott, TX, USA). At last, we offer our outlook on future developments with dorsal root ganglion stimulation.

Effect of ankle dorsiflexion on displacement and strain in the tibial nerve and biceps femoris muscle at the posterior knee during the straight leg raise: Investigation of specificity of nerve movement.

BACKGROUND: A structural differentiation maneuver has been proposed to differentiate between muscle and nerve involvement during the straight leg raise test. However, to date, the mechanical specificity of this maneuver for the tibial nerve at the posterior knee has not been tested. The aim of this study was to investigate the specificity of ankle dorsiflexion as a differentiation maneuver between the tibial nerve and the biceps femoris muscle at the posterior knee during the straight leg raise in cadavers. METHODS: A cross-sectional study was carried out. In fresh frozen cadavers, with microstrain devices and Vernier calipers, strain and excursion in the tibial nerve and distal biceps femoris muscle were measured during ankle dorsiflexion at 0°, 30°, 60° and 90° of hip flexion of the straight leg raise. FINDINGS: Ankle dorsiflexion resulted in significant distal excursion and increased strain in the tibial nerve (p < 0.05) whilst the muscle was not affected by the dorsiflexion (p > 0.05) at all hip flexion angles. INTERPRETATION: Ankle dorsiflexion was mechanically specific between the tibial nerve and biceps femoris during the straight leg raise. This study adds to evidence that, in certain circumstances, dorsiflexion may be used in differentiation of nerve and muscle disorders in the posterior knee.

Ultrasound-guided cooled radiofrequency ablation of the genicular nerves: a technique paper.

Aim: Cooled radiofrequency ablation (CRFA) has demonstrated efficacy in the management of knee pain caused by osteoarthritis. A typical procedure involves fluoroscopic placement of internally cooled radiofrequency probes to ensure the probes are located near target genicular nerves. Patients & methods: A new technique was developed to perform CRFA using ultrasound (US) guidance. Patient outcomes were reported using a telephone survey. Results: Ablation procedures were successfully performed using US guidance. A total of 51 patients were retrospectively identified for telephone screening. A total of 22 patients completed the telephone questionnaire. There were no safety concerns identified and the majority of patients reported satisfactory outcomes. Conclusion: Patient outcomes demonstrate that US-guided CRFA procedures provide pain relief and functional improvement. Further studies are needed to compare the efficacy of US-guided CRFA to fluoroscopy-guided CRFA procedures.

Disparate kinetics of change in responses to electrical stimulation at the thoracic and lumbar level during fatiguing isometric knee extension.

The present study compared the fatigue-induced change of matched-amplitude thoracic evoked potential (TMEP) and lumbar evoked potential (LEP) following electrical stimulation. Ten participants performed a 3 × 3 min isometric knee extension contraction separated by 4 min of recovery at the level of EMG required to produce 50% maximal voluntary contraction (MVC) force at baseline. The TMEP and LEP were evoked during the ongoing contraction at baseline and every minute into the fatiguing protocol and during recovery. Both responses were also assessed during a transcranial magnetic stimulation (TMS) evoked silent period to elicit a TMS-TMEP and TMS-LEP to assess responses without the confounding influence of descending drive. The results displayed disparate kinetics of the TMS-TMEP and TMS-LEP throughout the fatiguing protocol. The TMS-TMEP was reduced at all time points during exercise (P < 0.001), whereas the TMS-LEP was reduced at 2 min into set 1 and 1 min into sets 2 and 3 (P ≤ 0.04). TMS-LEPs were higher than the TMS-TMEPs at most time points (P ≤ 0.04). No change was observed in the TMEP or LEP. When evoked during the silent period, the reduction in TMEP is greater than the LEP during fatiguing isometric exercise. The disparate kinetics of change suggest that differential mechanisms are responsible for evoked responses to thoracic and lumbar stimulation. More research is required to identify the mechanisms responsible for the TMEP and LEP before precise inferences can be made on what fatigue-induced changes in these variables reflect.NEW & NOTEWORTHY Assessing spinal excitability using lumbar stimulation when measuring responses in lower limbs has been suggested as an alternative method that could circumvent the issues associated with thoracic stimulation. The present study compared responses to the two types of stimuli throughout a fatiguing protocol and demonstrated that lumbar evoked responses differ substantially from thoracic responses when measured in the absence of voluntary drive. These findings suggest that different mechanisms are responsible for evoked responses to thoracic and lumbar stimuli.

Contralateral Obturator Nerve to Femoral Nerve Transfer for Restoration of Knee Extension After Acute Flaccid Myelitis: A Case Report.

CASE: A 7-year-old boy presented with left femoral and obturator nerves (ONs) palsy after an asthmatic attack with a viral prodrome, and his right lower limb was unaffected. He was diagnosed with acute flaccid myelitis (AFM) after positive spinal magnetic resonance imaging findings. After contralateral ON to femoral nerve transfer (CONFNT), his left quadriceps was reinnervated at 5.5 months, full knee extension was recovered at 14 months, and good functional outcomes were achieved at 31 months. CONCLUSIONS: This first clinical report on CONFNT demonstrated a feasible good alternative in treating young patients with AFM with unilateral L2-L4 palsy and short duration of deficit.

Bloqueos de los nervios geniculados de la rodilla: ¿lo estamos haciendo bien? / Genicular nerve blockade: are we doing well?

No disponible

Anatomical study of the infrapatellar branch of the saphenous nerve with applications to knee surgery / Estudio anatómico de la rama infrapatelar del nervio safeno con aplicaciones a la cirugía de rodilla

The infrapatellar branch of the saphenous nerve is a cutaneous nerve that innervates the area surrounding the patella and contributes to the peripatellar plexus. This nerve is target to iatrogenic injuries during a great deal of knee procedures, such as tendon harvesting, total knee arthroplasty and medial arthroscopic approaches to the knee. Lesion to this nerve can produce sensorial loss at its innervation territory. The study conducted herein aims to observe the anatomical aspects of the infrapatellar branch in cadaveric specimens. The infrapatellar branch of the saphenous nerve of 40 male cadavers was dissected with the purpose of identifying the number of branches, its relation with the patella, tibial tuberosity and sartorius muscle. The nerve was dissected and several measurements were performed with the aid of a digital caliper. Statistical analysis was performed with the MedCalc 16.1 software. The infrapatellar branch of the saphenous nerve was present in 100 % of the sample. Its mean distance from its origin to its branching point was 16.35±6.48 mm on the right and 21.94±4.31 mm on the left, with statistically significant differences (p < 0.05). A relatively safe zone for surgery was observed on the superior and medial aspect of the patella, which received less branches.

La rama infrapatelar del nervio safeno es un nervio cutáneo que inerva el área que rodea la patela y contribuye al plexo peripatelar. Este nervio es objeto de lesiones iatrogénicas durante una gran cantidad de procedimientos de rodilla, como la extracción de tendones, la artroplastía total de rodilla y los abordajes artroscópicos mediales de la rodilla. La lesión de este nervio puede producir pérdida sensorial en su territorio de inervación. El estudio realizado aquí tiene como objetivo observar los aspectos anatómicos de la rama infrapatelar en muestras de cadáveres. La rama infrapatelar del nervio safeno de 40 cadáveres masculinos se disecó con el propósito de identificar el número de ramas, su relación con la patela, la tuberosidad tibial y el músculo sartorio. Se disecó el nervio y se realizaron varias mediciones con la ayuda de un calibrador digital. El análisis estadístico se realizó con el software MedCalc 16.1. La rama infrapatelar del nervio safeno estaba presente en el 100 % de las muestras. La distancia media desde su origen hasta su punto de ramificación fue de 16,35±6,48 mm a la derecha y de 21,94±4,31 mm a la izquierda, con diferencias estadísticamente significativas (p <0,05). Se identificó una zona relativamente segura para la cirugía en el aspecto superior y medial de la patela, que recibió menos ramas.

Sensory feedback restoration in leg amputees improves walking speed, metabolic cost and phantom pain.

Conventional leg prostheses do not convey sensory information about motion or interaction with the ground to above-knee amputees, thereby reducing confidence and walking speed in the users that is associated with high mental and physical fatigue1-4. The lack of physiological feedback from the remaining extremity to the brain also contributes to the generation of phantom limb pain from the missing leg5,6. To determine whether neural sensory feedback restoration addresses these issues, we conducted a study with two transfemoral amputees, implanted with four intraneural stimulation electrodes7 in the remaining tibial nerve (ClinicalTrials.gov identifier NCT03350061). Participants were evaluated while using a neuroprosthetic device consisting of a prosthetic leg equipped with foot and knee sensors. These sensors drive neural stimulation, which elicits sensations of knee motion and the sole of the foot touching the ground. We found that walking speed and self-reported confidence increased while mental and physical fatigue decreased for both participants during neural sensory feedback compared to the no stimulation trials. Furthermore, participants exhibited reduced phantom limb pain with neural sensory feedback. The results from these proof-of-concept cases provide the rationale for larger population studies investigating the clinical utility of neuroprostheses that restore sensory feedback.

Valoración de la efectividad y seguridad de dos técnicas de radiofrecuencia para el tratamiento de la gonalgia secundaria a gonartrosis. Estudio prospectivo randomizado doble ciego / Assessment of the effectiveness and safety of two radiofrequency techniques for the treatment of knee pain secondary to gonarthrosis. Prospective randomized double blind study

Antecedentes y objetivo: En los pacientes con gonalgia por gonartrosis, disponemos de tratamientos no exentos de efectos secundarios. Objetivo: evaluar la eficacia analgésica de la radiofrecuencia (pulsada y convencional) sobre el nervio safeno a nivel subsartorial y los nervios geniculares de la rodilla, mediante la localización por ultrasonografía. Materiales y métodos: Ensayo clínico prospectivo, aleatorizado, doble ciego. G1 (RDF1): sujetos sometidos a radiofrecuencia, G2 (PLCB): sujetos sometidos a placebo. Se consideró clínicamente relevante una disminución ≥30% del dolor, según escala visual numérica y en el Western Ontario and McMaster Universities Osteoartritis Index, cuestionario de impresión global del paciente (PGIC) y cuestionario de estado de salud (SF-12) en la evaluación al mes, a los tres meses y a los seis meses de la realización de la técnica. Resultados: Veintiocho pacientes (G1: 12, G2: 16), 72% mujeres, edad: 75,2 (9,1) años, índice de masa corporal: 29,9 (4,64). El análisis no mostró una reducción del dolor, ni estadísticamente significativa, ni clínicamente relevante, al mes, tres, o seis meses respecto al inicio del tratamiento, en el cuestionario Western Ontario and McMaster Universities Osteoartritis Index y en la escala visual numérica (reposo, movimiento). Respecto al PGIC y al cuestionario SF-12, tampoco existieron diferencias estadísticamente significativas entre G1 y G2 antes ni después del tratamiento. Conclusiones: La combinación de dos técnicas de radiofrecuencia, no provoca una reducción en la intensidad de la gonalgia, al mes, tres, ni a los seis meses después de su realización. Es necesario cambiar la técnica de radiofrecuencia e incluir más variables para proseguir con el estudio de eficacia

Background and objective: In patients with knee pain due to gonarthrosis, we have treatments that are not free of side effects. Objective: to evaluate the analgesic efficacy of radiofrequency (pulsed and conventional) on the saphenous nerve at the subsartorial level and the genicular nerves of the knee, by ultrasonography. Materials and methods: Prospective, randomized, double-blind clinical trial. G1 (RDF1): subjects subjected to radiofrequency, G2 (PLCB): subjects subjected to placebo. A decrease ≥30% of the pain was considered clinically relevant, according to numerical rating scale and in the Western Ontario and McMaster Universities Osteoarthritis Index, global patient impression questionnaire (PGIC) and health status questionnaire (SF-12) in the evaluation at month, three months and six months after the completion of the technique. Results: 28 patients (G1: 12, G2: 16), 72% women, age: 75.2+/-9.1 years, body mass index: 29.9+/-4.64. The analysis did not show a pain reduction, neither statistically significant, not clinically relevant, at one month, three, or six months with respect to the start of treatment, in the Western Ontario and McMaster Universities Osteoarthritis Index questionnaire and numerical rating scale (rest, movement). Regarding PGIC and the SF-12 questionnaire, there were no statistically significant differences between G1 and G2 either before or after treatment. Conclusions: The combination of two radiofrequency techniques, does not cause a reduction in the intensity of the knee pain, at month, three, or at six months after its completion. It is necessary to change the radiofrequency technique and include more variables to continue with the efficacy study

Continuous adductor canal blockade facilitates increased home discharge and decreased opioid consumption after total knee arthroplasty.

BACKGROUND: There is a growing interest in avoiding discharging patients to rehab to maximize outcome and minimize complications after total knee arthroplasty (TKA). In addition, use of postoperative pain pathways that minimize opioid use is critical amidst the current opioid epidemic. However, the ideal pain regimen after TKA has yet to be determined. METHODS: From July 1, 2013 to October 1, 2014 two perioperative pathways were used to address surgical pain. These included either a single shot femoral nerve block plus liposomal bupivacaine pericapsular injection (FNB + LB-PAI) or adductor canal catheter plus posterior capsule single shot block (ACC + iPACK), each with an oral analgesic protocol. Little modification occurred with regard to surgical technique, postoperative medications, or postoperative physical therapy (PT). RESULTS: Overall, 264 unilateral, primary TKA patients (146 FNB + LB-PAI, 118 ACC + iPACK) were included. ACC + iPACK patients had a shorter median length of stay (LOS, 2.0 vs 3.0, p < 0.001), more discharges home (79.7% vs 67.8%, p = 0.002), and less median opioid consumption (IV morphine equivalents, IVME, 20.0 vs 44.1, p < 0.001) than the FNB + LB-PAI group. In multivariable analysis, use of ACC + iPACK remained independently associated with shorter LOS, increased discharge home, and less IVME consumed when controlling for confounding variables. ACC + iPACK patients also had fewer opioid related adverse events (0.8 vs 5.5, p = 0.045) and a lower rate of MUA (0.8% vs 6.2%, p = 0.026). CONCLUSIONS: We recommend ACC + iPACK with a multimodal oral analgesic protocol as the primary postoperative analgesia in enhanced recovery TKA protocols. This resulted in an easier recovery with fewer complications. LEVEL OF EVIDENCE: Level III.

Neuromuscular electrical stimulation increases serum brain-derived neurotrophic factor in humans.

Brain-derived neurotrophic factor (BDNF) plays several important roles in nervous system function including neuronal growth and plasticity. The purpose of the present study was to clarify whether neuromuscular electrical stimulation (NMES) and voluntary exercise to the same integrated force as by the NMES-induced exercise would enhance serum BDNF. Eleven healthy male subjects completed three interventions (NMES, voluntary exercise, and resting interventions) for 20 min on different days. In the NMES intervention, NMES was applied to the quadriceps femoris muscles. The stimulus intensity of NMES was progressively increased to the highest tolerated intensity during the experiment. In the voluntary exercise intervention, subjects performed an isometric knee-extension task; in this intervention, the target torque was calculated in accordance with the integrated force of knee extension obtained during the NMES intervention. In the resting intervention, subjects relaxed in a sitting posture. We measured serum BDNF, blood lactate, heart rate, oxygen uptake, respiratory ratio, and blood pressure. Serum BDNF was increased in the NMES (p = 0.003) and voluntary exercise interventions (p = 0.004) after each intervention. At the post-timepoint, serum BDNF in the NMES intervention was highest among all interventions (p = 0.038) and significantly higher than in the voluntary exercise (p = 0.036) and resting (p = 0.037) interventions. Our results showed that NMES was more effective for enhancing serum BDNF than voluntary exercise at least when employing the same method and integrated force.

Muscle force strategies for poststroke hemiparetic patients during gait.

BACKGROUND AND OBJECTIVE: Individuals who survive a stroke often display considerable gait impairments that occur in part due to inadequate muscle force production. This study aimed to investigate lower limb muscle forces in poststroke patients during walking. METHODS: Kinematics, kinetics, and electromyographic (EMG) measurements were performed on nine poststroke and healthy individuals walking at natural speed in a cross-sectional study. Recorded parameters were used in an EMG-driven model to estimate the forces exerted by the muscles around the knee and ankle joints during the stance (braking and propulsion) and swing phases. RESULTS: For hemiparetic patients, in comparison to healthy controls, the paretic side exhibited (i) lower forces generated by plantar-flexors and quadriceps respectively during the braking and propulsion phases, but (ii) higher knee-flexors forces during the propulsion phase. Regarding the non-paretic side, it displayed (i) higher forces generated by knee-flexors and quadriceps (only for the propulsion phase) forces during the stance phase, and (iii) higher plantar-flexors forces during the swing phase, in comparison to controls. CONCLUSION: Reduced forces exerted by the plantar-flexors and the knee-extensors along with increased force generated by the knee-flexors on the paretic side give possible explanation for hemiparetic gait abnormalities. Increased muscle forces exerted by the non-paretic side might be a compensatory strategy to better support body weight and properly adjust the center of mass forward.

Adductor Canal Block or Local Infiltrate Analgesia for Pain Control After Total Knee Arthroplasty? A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Total knee arthroplasty is a treatment option for debilitating arthritis. In the postoperative period, patients experience moderate to severe pain affecting the rehabilitation, hospital stay, and patient satisfaction. This study aims at utilizing current best evidence to determine whether adductor canal block (ACB) or periarticular injection (PAI) is a better modality for managing short-term postoperative pain and opioid consumption. METHODS: Embase, MEDLINE, HealthStar, Emcare, and PubMed were searched for randomized controlled trials from 1946 to August 2018, for literature addressing the comparison of ACB and PAI for pain management in the setting of total knee arthroplasty. A systematic review and meta-analysis were performed. RESULTS: Six studies were included in our meta-analysis. When examining the combined visual analog scale (VAS) pain values for each group, analysis demonstrated greater reduction in scores for the PAI group, and the difference was statistically significant (P = .001). When comparing the VAS scores of subgroups analyzed at specific periods in time, there was a trend toward lower VAS scores in subgroups analyzed at 24 hours and 48 hours postoperatively (at rest and at movement) in the PAI group. Overall opioid consumption was lower in the PAI group, with demonstrated statistical significance (P = .03). When comparing the postoperative subgroups, there was a trend toward decreased opioid use in the PAI group, with 13.25% less opioid use at 48 hours and 9.5% less opioid use at 24 hours. CONCLUSION: PAI could significantly improve postoperative pain and opioid consumption when compared with ACB. Additional, high-quality studies are required to further address this topic.