Investigation of Optimal Needle Position for Radiofrequency Ablation-Based Blockade of Interspace between the Popliteal Artery and the Posterior Capsule of the Knee: A Cadaveric Study.

Background and Objectives: The interspace between the popliteal artery and the posterior capsule of the knee (iPACK) block has been widely used in perioperative settings to control posterior knee pain and can additionally be used for chronic knee pain. In this cadaveric study, we aimed to investigate the needle tip position and its proximity to the articular branch of the tibial nerve (ABTN) during an iPACK-targeted radiofrequency procedure. Materials and Methods: An ultrasound-guided iPACK block was performed on 20 knees of 10 cadavers. We injected 0.1 mL each of blue and green gelatinous dye near the tibial artery (point A) and posterior knee capsule (point B), respectively, and evaluated the spread of both around the ABTN. For a hypothetical conventional radiofrequency ablation (RFA) lesion (diameter, 2.95 mm) and cooled RFA lesion (diameter, 4.9 mm), we counted the number of specimens in which the ABTNs would be captured. Results: The percentage of specimens in which the ABTN would be captured by a cooled RFA lesion was 64.71% at point A and 43.75% at point B (p = 0.334). Meanwhile, the percentage of specimens in which the ABTN would be captured by a conventional RFA lesion was 58.82% from point A and 25% from point B (p = 0.065). Conclusions: When performing an RFA-based iPACK block, the needle tip may be positioned either lateral to the tibial artery or in the space between the posterior knee capsule and the tibial artery. However, more studies with larger samples are needed to verify these results before the clinical use of this procedure can be recommended.

Evaluation of Factors Affecting Illumination Intensity in Lightwand Endotracheal Intubation.

BACKGROUND/AIM: A lightwand is a stylet with a light bulb at its tip that can be used to guide intubation by confirming the illumination through the anterior neck. We aimed to determine the factors affecting the illumination intensity during lightwand endotracheal intubation. PATIENTS AND METHODS: We retrospectively collected data from 180 patients who underwent lightwand endotracheal intubation. We recorded illumination intensity on a 5-point scale. The patients were categorized into weak (score <3) and bright (score ≥3) groups based on the illumination intensity scale score. RESULTS: A total of 176 patients were analyzed, of whom 125 (71.1%) were enrolled in the bright group, and 51 (29.0%) were enrolled in the weak group. Multivariable logistic regression analysis revealed that an increased body mass index (BMI) and mask ventilation grade were associated with light intensity. For mask ventilation, moderate vs. easy (p=0.010) and difficult vs. easy (p=0.008) were associated with the weak group. Receiver operating characteristic curve analysis showed that BMI ≥24.6 kg/m2 was correlated with the weak group. CONCLUSION: BMI ≥24.6 kg/m2 or mask ventilation grade above moderate indicates increased odds of weak illumination intensity in lightwand intubation. Pre-intubation examination of these factors helps increase the chances of successful intubation.

Comparison of injectate spread and nerve coverage between single-injection intertransverse process block and paravertebral block at the T2 level: a cadaveric study.

BACKGROUND: We compared the spread of an injectate into the thoracic sympathetic chain resulting from a single-injection intertransverse process (ITP) block with that of a single-injection PV block at the T2 level. METHODS: Sixteen soft-embalmed cadavers were used. The right hemithorax was randomly allocated to receive either an ultrasound-guided single-injection ITP block or ultrasound-guided single-injection PV block at the T2 vertebral level, with the opposite block administered to the other side. Approximately 10 mL of latex dye solution was injected into each hemithorax using a random allocation technique. The presence of dye at the nerve root in the sympathetic chain and intercostal nerves at the injection and additional levels was examined by dissection. RESULTS: The injectate spread into the T2 sympathetic ganglion on both ITP (11/16, 68.8%) and PV (16/16, 100%) blocks. The ITP block demonstrated greater uniformity of dye staining in both the dorsal rami and dorsal root ganglion, which contrasts with the less consistent staining outcomes of the PV block in these regions. CONCLUSIONS: At the T2 level, we observed a lower efficacy of the ITP block for analgesic coverage of the sympathetic nerve. This suggested a potential preference by clinicians for the application of the T2 PV block over the ITP block, specifically for the management of sympathetically maintained pain in the upper extremities. In addition, our findings may hint at the potential advantages of the ITP block in specific clinical contexts where targeted nerve involvement, such as the medial branch block or dorsal root ganglion block, is sought.

Milnacipran Has an Antihyperalgesic Effect on Cisplatin-Induced Neuropathy.

(1) Background: Milnacipran is a typical serotonin-norepinephrine reuptake inhibitor and has been shown to have analgesic effects in several pain models. However, its antihyperalgesic effect in cisplatin-induced neuropathy remains unknown. We examined the effects of intraperitoneal (IP) milnacipran on allodynia in cisplatin-induced peripheral neuropathic mice. (2) Methods: Peripheral neuropathy was induced by injecting cisplatin (2.3 mg/kg/day, IP) six times, on every other day. Saline or milnacipran (10, 30, 50 mg/kg, IP) were then administered to the neuropathic mice. We examined mechanical allodynia using von Frey hairs at preadministration and at 30, 60, 90, 120, 180, 240 min and 24 h after drug administration. We also measured the dorsal root ganglion (DRG) activating transcription factor 3 (ATF3) to confirm the analgesic effects of milnacipran. (3) Results: For the milnacipran groups, the decreased paw withdrawal thresholds to mechanical stimuli were significantly reversed when compared to the preadministration values and the values in the saline-injected control group (p < 0.0001). Milnacipran administration to cisplatin-induced peripheral neuropathic mice resulted in a significant suppression of neuronal ATF3 activation (p < 0.01). (4) Conclusions: Milnacipran given via IP injection attenuates mechanical allodynia in mouse models of cisplatin-induced poly-neuropathic pain. These effects were confirmed by significant suppression of neuronal ATF3 activation in the DRG.

Non-Surgical Treatments of Trigeminal Neuralgia from the Perspective of a Pain Physician: A Narrative Review.

Trigeminal neuralgia (TN) is a unilateral disorder characterized by electric shock-like pain, abrupt onset and termination, and limited to one or more branches of the trigeminal nerve. Various therapeutic modalities for TN have been introduced. We searched for literature indexed in PubMed, Medline, and the National Library of Medicine and reviewed all relevant articles on non-surgical treatments for TN. Published studies were reviewed with no restrictions on date; reviews, clinical trials, animal studies, retrospective studies, and cases were included. Carbamazepine and oxcarbazepine are the recommended first-line pharmacotherapies. Interventional treatments should be considered when pharmacotherapy is insufficient or withdrawn because of adverse effects.

Investigation of the existence of and a block technique for the inferior lateral genicular nerve: cadaveric study.

Background: Among the four genicular nerves innervating the anterior aspect of the knee, the inferior lateral genicular nerve has been omitted as a target of blocking. Some authors have suggested that the inferior lateral genicular nerve of the knee might pass beneath the lateral collateral ligament of knee. The authors aimed to study the location of the inferior lateral genicular nerve and the spread of injectate during the inferior lateral genicular nerve block. Methods: In ten knees from fresh frozen cadavers, the authors performed on each an ultrasound-guided block of the inferior lateral genicular nerve of the knee just below the lateral collateral ligament. The needle was inserted below the lateral collateral ligament, and 2 mL of blue dye was injected. A week later, the cadavers were dissected, and the existence of the inferior lateral genicular nerve and the spread of dye around it was investigated. Results: The proportion of inferior lateral genicular nerves branching from the common peroneal nerve was found in 8 of 10 (80.0%) cadavers. Of these eight cadavers with inferior lateral genicular nerve, five specimens (62.5%) were stained with blue dye. The common peroneal nerve was not infiltrated with dye in any specimens. Conclusions: When 2 mL of dye was inserted inferiorly to the lateral collateral ligament, the inferior lateral genicular nerve could be blocked in 62.5% of specimens. Because the common peroneal nerve was not involved in any specimen, motor weakness would be avoided with this method.

Latent infection after spinal cord stimulation device implantation for complex regional pain syndrome: A case report.

RATIONALE: Spinal cord stimulation (SCS) is one of the invasive treatments of complex regional pain syndrome (CRPS). The positive effect has been observed for several years after implantation. However, infection is a common cause of SCS failure and device removal. PATIENT CONCERNS: Here we describe a case of latent infection at the implantable generator pocket site 9 years after SCS implantation in a patient with CRPS. DIAGNOSES: A 52-year-old patient was diagnosed with type 1 CRPS. The right foot pain was intractable with standard treatments. SCS implantation was performed and SCS worked well without complication. Nine years later, the patient revisited due to pain, tenderness, and redness at the abdominal wall for 2 weeks. The right foot pain was maintained with NRS 4 for 8 years, and the stimulation stopped 1 year back. SCS infection was diagnosed. INTERVENTIONS: The patient underwent SCS removal surgery. OUTCOMES: All SCS devices were removed successfully. The patient was discharged without any complications. CONCLUSIONS: While uncommon, infection after SCS implantation can occur even 9 years later. Immediate diagnosis, proper antibiotics, and surgical removal could be needed to prevent further spread of infection and better prognosis.

Blood Biomarkers in Patients with Parkinson's Disease: A Review in Context of Anesthetic Care.

Parkinson's disease (PD) is the second most common inflammatory neurodegenerative disorder after dementia. Preclinical and epidemiological data strongly suggest that chronic neuroinflammation slowly induces neuronal dysfunction. Activated microglia secrete several neurotoxic substances, such as chemokines and proinflammatory cytokines, which may promote blood-brain barrier (BBB) permeabilization. CD4+ T cells comprise proinflammatory cells such as T helper (Th) 1 and Th17 cells, as well as anti-inflammatory cells such as Th2 and T regulatory cells (Tregs). Th1 and Th17 cells can be detrimental to dopamine neurons, whereas Th2 and Tregs are neuroprotective. The results of studies on the serum levels of cytokines such as IFN-γ and TNF-α secreted by Th1 T cells, IL-8 and IL-10 secreted by Th2 T cells, and IL-17 secreted by Th17 cells in PD patients are not uniform. In addition, the relationships between serum cytokine levels and motor and non-motor symptoms of PD are controversial. Surgical stress and anesthesia induce inflammatory responses by disturbing the balance between pro- and anti-inflammatory cytokines, which may exacerbate the neuroinflammatory response in PD patients. Here we review studies on blood inflammatory biomarkers in PD patients and discuss the roles of surgery and anesthesia in PD progression.

Anatomical and Radiological Assessments of Injectate Spread Stratified by the Volume of the Pericapsular Nerve Group Block.

BACKGROUND: The pericapsular nerve group (PENG) block was recently suggested as a regional technique for managing acute pain after hip surgery. However, few anatomical studies have confirmed the spread of injectate during the PENG block. This cadaver study aimed to analyze injectate spread to the target nerves during single-injection ultrasound-guided PENG block. METHODS: Ultrasound-guided PENG block with 3 different injectate volumes (10, 20, or 30 mL) was performed in 18 cadavers. Injectate spread by the volume was first evaluated on computed tomography, followed by cadaver dissection. The spread of the dye over the pelvis and lower limb was evaluated. RESULTS: The articular branches of the femoral nerve were stained nearly sufficiently with 20- and 30-mL specimens. The femoral nerve itself was stained simultaneously in six of 12 (50%) 20-mL specimens and 12 of 12 (100%) 30-mL specimens. The accessory obturator nerve was observed only in three (9%) of 36 specimens. The articular branches of the obturator nerve were rarely affected, regardless of injectate volume (1/12, 10 mL specimens; 2/12, 20 mL specimens; 1/12, 30 mL specimens; P > .999). Rather, the obturator nerve was affected. However, the obturator nerve was not stained consistently even with 30 mL of injectate (50%). CONCLUSIONS: After combining the dissection and radiological findings, the single-injection ultrasound-guided PENG blocks with volumes of 10, 20, and 30 mL do not support motor sparing or selective anterior hip capsule innervation in a clinical setting. If early rehabilitation is needed, high-volume PENG block might not be the ideal option, and persisting pain after PENG block might be attributed in part to the lack of obturator nerve articular branches blockade.

Comparison of Polynucleotide, Sodium Hyaluronate, and Crosslinked Sodium Hyaluronate for the Management of Painful Knee Osteoarthritis: A Multi-Center, Randomized, Double-Blind, Parallel-Group Study.

OBJECTIVE: To compare the clinical effectiveness of sodium polynucleotide, classic hyaluronic acid, and crosslinked hyaluronic acid for the management of painful knee osteoarthritis. DESIGN: Randomized, double-blind, parallel-group clinical trial. SETTING: Multicenter study. SUBJECTS: Patients with chronic painful knee osteoarthritis. METHODS: Ninety patients were selected and randomized into polynucleotide, classic hyaluronic acid, and crosslinked hyaluronic acid groups (30 per group). Intra-articular injections of the viscosupplement for each group were administered to the patients three times at one-week intervals. The primary outcome was differences in changes of weight-bearing pain scores at 16 weeks between the groups. The secondary outcomes were changes in the intensity of knee pain during weight-bearing, walking, and rest, and functional disability, quality of life, and adverse events during the 16-week follow-up period. RESULTS: At 16 weeks, the polynucleotide group showed a higher reduction in pain score using a Visual Analog Scale score (0-100) than the classic hyaluronic acid (-17.6 [95% CI = -35.1 to -0.1]; P = .048) and crosslinked hyaluronic acid (-22.4 [95% CI = -41.5 to -3.3]; P = .016) groups. The polynucleotide and crosslinked hyaluronic acid groups showed an early-onset reduction in knee pain during weight-bearing, walking, and rest. All three groups showed reductions in functional disability and improved quality of life at 16 weeks without inter-group differences. No severe adverse events were reported throughout the study period. CONCLUSION: Polynucleotide significantly relieves pain more and relieves pain faster in patients with knee osteoarthritis than classic and crosslinked hyaluronic acid, with improved health-related quality of life.

The development of prediction model for cuffed tracheal tube size from the middle finger in pediatrics: a concise and feasible approach.

Background: Selecting the optimal tracheal tube size is critically important for pediatric patients. Age-based formulas are often used, but still have limitations. The aim of this prospective study was to investigate whether middle finger measurements correlate with cuffed tracheal tube size and to further develop a prediction model based on these measurements. Methods: Patients under 12 years of age scheduled for elective surgery involving tracheal intubation were enrolled in the study. The length was determined from the tip of the distal metacarpal to the palm's root on the palm side, while the circumference was measured at the base of the palm using a soft tape measure. The appropriate cuffed tracheal tube size was determined based on specific criteria. If the tube encountered resistance during insertion or required an airway pressure >25 cmH2O to detect an audible leak, it was replaced with a tube 0.5 mm smaller. Conversely, if an audible leak occurred at an airway pressure <10 cmH2O, or peak pressure >25 cmH2O, or the cuff pressure >25 cmH2O to achieve a seal, the tube was exchanged for one with a 0.5 mm larger. Linear regression analysis was used to examine the association between middle finger circumference and length with the cuffed tracheal tube size. Subsequently, regression equations were constructed based on the results of the linear regression analysis and their predictive performance was compared to the conventional age-based formulas, including the Khine formula and Motoyama formula. The predictive performance was evaluated by mean absolute error (MAE), root mean square error (RMSE), and prediction accuracy. Results: A total of 261 patients were analyzed in our study. The mean age of the patients was 46.19±35.83 months. The linear relationship was observed between the cuffed tracheal tube size and the middle finger circumference and middle finger length with R2 values of 0.77 and 0.73, respectively. In comparison to conventional age-based formulas, both middle finger circumference and middle finger length demonstrated superior predictive performance, characterized by lower MAE and RMSE, as well as higher prediction accuracy. Notably, the regression equation based on the middle finger circumference obtained the higher predictive accuracy of 0.590, with an MAE of 0.259 and an RMSE of 0.333 as opposed to the predictive accuracy of 0.391, MAE of 0.349, and RMSE of 0.473 derived from conventional age-based formulas. Based on the regression coefficients of linear regression, simplified formulas were proposed, with the middle finger circumference-based formula emerging as the most accurate and simple option. Conclusions: The appropriate cuffed tracheal tube size could be predicted by the middle finger circumference. Our proposed formula 'cuffed tracheal tube internal diameter (mm) = middle finger circumference (cm) - 0.2' has the potential to improve the selection of the cuffed tracheal tube size in pediatric patients.

Effects of high-dose opioid analgesia on survival, pain relief, quality of life and adverse drug reactions in cancer and neuropathic pain patients: a retrospective cohort study in real-world clinical practice.

Background: Pain is a common symptom among cancer patients and directly affects their prognosis. As the leading drug for pain management, opioids are widely prescribed. So it is necessary to get people a correct understanding and application of opioids. In order to examine whether the use of high-dose opioids might affect survival and quality of life, this retrospective cohort study was performed to explore the outcomes of patients receiving high-dose opioids for pain management in a first-class tertiary hospital in China. Methods: We retrospectively searched medical records of inpatients and outpatients with pain who were treated with opioids in The First Affiliated Hospital, Zhejiang University School of Medicine from July to December 2021. Forty-three cases who were treated with high-dose opioids meeting inclusion criteria. Among these patients, 37 had cancer pain and 6 had neuropathic pain. All patients had regular follow-up when readmission until to April 7, 2022. Medical records of patients on high-dose opioids (equivalent to morphine ≥300 mg/d) was collected, including numerical rating scale (NRS), Karnofsky performance score (KPS), survival and adverse drug reactions (ADRs). Pain relief, quality of life, survival, and ADRs of patients after pain treatment were analyzed and evaluated. Results: The NRS score was significantly reduced and pain was relieved after high-dose opioid treatment. The before and after average NRS score of cancer pain was 5.2±1.6 vs. 2.2±1.1 points (P<0.001), neuropathic pain was 5.0±2.2 vs. 1.3±1.2 points (P<0.05), respectively. Although there is no statistical difference, quality of life showed a trend of improvement compared with before treatment. The before and after average KPS scores of cancer pain patients was 55.7±17.3 vs. 62.4±20.0, and neuropathic pain patients was 71.7±9.0 vs. 83.3±4.7. There were no intolerable ADRs. The median survival time was 238 days and 83 days in patients with cancer pain who received high-dose opioids and ultra-high dose opioids (equivalent to morphine ≥600 mg/d). Conclusions: Multimodal high-dose opioid pain treatments are important approaches to effectively relieve moderate to severe pain and improve the quality of life of patients. This study provides a clinical basis for future pain treatment with high-dose opioids.

Effect of Previous Caudal Block to Predict Successful Outcome after Adhesiolysis using a Steerable Catheter in Lumbar Failed Back Surgery Syndrome: A Retrospective Study.

Adhesiolysis is minimally invasive and commonly used for pain associated with adhesion after lumbar spine surgery. Caudal epidural block may be used for radiating pain due to failed back surgery syndrome. We evaluated the predictive value of response to caudal block performed prior to adhesiolysis in failed back surgery syndrome. Between January 1, 2013 and June 30, 2020, 150 patients with failed back surgery syndrome were treated with adhesiolysis using a steerable catheter at the pain clinic of a tertiary hospital after failed conservative treatment (including caudal block). Patient demographics, pain duration, and lumbar magnetic resonance imaging findings were examined. Response to previous caudal block was determined as a binary result (yes or no). Patients were followed up 3 months after adhesiolysis. Successful outcome was defined as a ≥2-point reduction in the numeric rating scale scores for radicular pain 3 months after adhesiolysis, evident in 81/150 (46%) patients. Multivariable logistic regression analysis revealed that caudal block response was an independent predictor of successful adhesiolysis (odds ratio = 4.403; p = 0.015). Response to prior caudal block is a positive predictor of successful adhesiolysis.

Effect of Pregabalin Combined with Duloxetine and Tramadol on Allodynia in Chronic Postischemic Pain and Spinal Nerve Ligation Mouse Models.

Although there are various drugs for Neuropathic pain (NP), the effects of single drugs are often not very satisfactory. The analgesic effects of different combinations of pregabalin, duloxetine, and tramadol or the combination of all three are still unclear. Mixtures of two or three drugs at low and high concentrations (7.5, 10, 15, and 20 mg/kg pregabalin; 7.5, 10, 15, and 30 mg/kg duloxetine; 5 and 10 mg/kg tramadol) were administered to chronic postischemic pain (CPIP) and spinal nerve ligation (SNL) model mice. The effects of these combinations of drugs on mechanical allodynia were investigated. The expression of the glial fibrillary acidic protein (GFAP) in the spinal cord and dorsal root ganglia (DRGs) was measured. The combination of pregabalin, duloxetine, and tramadol significantly alleviated mechanical hyperalgesia in mice with CPIP and SNL. After the administration of this drug combination, the expression of GFAP in the spinal cord and DRGs was lower in the CPIP and SNL model mice than in control mice. This result suggests that the combination of these three drugs may be advantageous for the treatment of NP because it can reduce side effects by preventing the overuse of a single drug class and exert increased analgesic effects via synergism.

Pain changes and new neurologic sign in post-herpetic neuralgia: a clue in the diagnosis of malignancy-a case report.

Herpes zoster (HZ) results from the reactivation of latent varicella-zoster virus in the dorsal root ganglion neurons. The most common complication of HZ is post-herpetic neuralgia (PHN), characterized by persisting neuropathic pain in the affected dermatome after the rash recedes. The immune system is more compromised in older people, which leads to an increase in the incidence of HZ and PHN. Several studies have revealed that HZ or PHN is associated with an increased risk of malignancy in immune-suppressed patients. An 83-year-old man visited our pain clinic with facial pain 6 months after he was diagnosed with recurred HZ on the right V1 dermatome. He was diagnosed with HZ on the right C2 dermatome 5 years ago. He could not perform a right lateral gaze for the past 3 months. Moreover, the symptoms did not improve and the pain was aggravated on the face and head. We considered two possibilities: HZ affecting motor neuron and occult malignancy. Brain magnetic resonance imaging and magnetic resonance angiography showed a mass lesion that should have been differentiated, and his blood was positive for prostate specific antigen. The probability of occult malignancy should be taken into account in elderly patients with HZ or PHN.

The analgesic effect of lumbar sympathetic ganglion block in patients with failed back surgery syndrome.

Background: Persistent or recurrent lumbosacral pain is a common symptom after spinal surgery. Several interventions have been introduced for failed back surgery syndrome; however, their clinical efficacy, safety, and cost-effectiveness are insufficient. Sympathetic ganglion block has been selected for pain associated with the sympathetic nervous system. In this study, we compared pain and quality of life in patients with failed back surgery syndrome who responded and did not respond to lumbar sympathetic ganglion block. Methods: We included 84 patients diagnosed with failed back surgery syndrome who had lumbosacral pain and underwent lumbar sympathetic ganglion block between January 2020 and April 2021. The patients' data were retrospectively analyzed; clinical outcomes were assessed before (T0), 1 week after (T1), and 4 weeks after (T4) lumbar sympathetic ganglion block. Based on the pain difference from T0 to T1, we categorized patients into two groups: patients with ≥ 50% pain reduction (responder group) and patients with < 50% pain reduction (non-responder group). Demographic, clinical, surgical, and fluoroscopic data were evaluated and compared. The primary outcome was pain scores and the EuroQol-5D score from T0 to T4. Results: Among the 84 patients analyzed, 41 (48.8%) experienced ≥ 50% pain reduction at 1 week after lumbar sympathetic ganglion block. Lumbar sympathetic ganglion block significantly improved pain at T1 and T4 compared to T0 in both groups. Lumbar sympathetic ganglion block improved the EuroQol-5D score at T1 compared to T0 in the responder group. The responder group had a significant decrease in pain at T1 from T0 and T4 from T0 and a significant decrease in the EuroQol-5D score at T1 from T0 compared with the non-responder group. Coldness of the leg over time did not differ between the groups. No serious adverse events occurred in either of the groups. Conclusion: Lumbar sympathetic ganglion block may improve pain at 1 and 4 weeks in patients with failed back surgery syndrome. Patients with ≥ 50% pain reduction at 1 week showed simultaneous improvement in quality of life and pain reduction at 4 weeks. Clinical trial registration: https://cris.nih.go.kr/cris/index/index.do, identifier KCT0007236.

Using the iPACK block to reduce chronic pain in a patient with knee osteoarthritis: A case report.

Infiltration between the popliteal artery and capsule of the knee (iPACK) block is an emerging modality to control perioperative knee joint pain. This case report describes the successful control of chronic knee joint pain using iPACK block in a patient with knee osteoarthritis. We suggest that iPACK block could be applied in the fields of both pain medicine and perioperative analgesia. In addition, by placing the needle closely to the popliteal plexus, iPACK block could serve as an intervention for pain related to procedures such as radiofrequency ablation.

Pilot Study to Evaluate the Efficacy of Polynucleotide Sodium Compared to Sodium Hyaluronate and Crosslinked Sodium Hyaluronate in Patients with Knee Osteoarthritis.

Degenerative arthritis of the knee joint has become a major social problem worldwide due to population aging. There are several treatment options for knee osteoarthritis, and the intraarticular injection of sodium hyaluronate is commonly selected by many clinicians as a nonsurgical treatment. However, the efficacy of the treatment is controversial. In this pilot study, we aimed to compare polynucleotide sodium (Conjuran®) with sodium hyaluronate (Hyruan Plus®) and 1,4-butanediol diglycidyl ether-crosslinked sodium hyaluronate (Synovian®) in terms of analgesic efficacy after intraarticular injection in patients with knee osteoarthritis. One of the three intraarticular agents was selected according to what agents were available for outpatients when each patient was enrolled in the study. The 15 enrolled patients were subdivided into 3 groups of 5 patients each. Three injections were performed under ultrasound guidance at a 1-week intervals over a total of 3 weeks. The visual analog scale (VAS) score, the Korean version of the Western Ontario and McMaster Universities Arthritis Index (K-WOMAC), the EuroQol five-dimension scale (EQ-5D) score, and the Korean version of the painDETECT Questionnaire (K-PDQ) score were evaluated before injection and at 1, 2, and 6 weeks after the start of the treatment protocol. The primary endpoint was the change in weight-bearing pain at 4 weeks after the last injection. Secondary endpoints included pain at rest and during walking and the K-WOMAC, EQ-5D, and K-PDQ scores. Weight-bearing pain decreased significantly more from pretreatment to 6 weeks after the start of the treatment protocol in the polynucleotide sodium-treated patients than in the patients who were treated with other agents (p = 0.006, one-way ANOVA). There were no significant between-group differences in the other secondary endpoints. No adverse events occurred. In conclusion, polynucleotide sodium could effectively reduce weight-bearing pain in the patients with knee osteoarthritis compared to standard hyaluronic acid viscosupplementation.