The in vitro chondrotoxicity of single-dose local anesthetics

Ultrasound-guided interventions in elite soccer players

In the world of elite soccer, or football as we call it in the UK, a player who cannot play for any length of time costs the team money and team performance. The time to return to play (RTP) is crucial in any player's career, and the use of ultrasound-guided ultrasound injections has become important in the management of injury. In this article, I will explain the importance of good practice when performing these procedures and the use of steroids, sodium hyaluronic acid, platelet-rich plasma (PRP), and other therapies in achieving the goal of decreasing the time of RTP for the footballer. KEY POINTS: •Injection therapies are routine practice in maintaining and treating soccer injuries. •Injection therapies can be safely performed under ultrasound guidance.

Ropivacaine and celecoxib-loaded injectable composite hydrogel for improved chronic pain-exacerbated myocardial ischemia-reperfusion injury

Chronic pain is a prevalent condition affecting a significant portion of the global population and is known to be associated with an increased risk of cardiovascular diseases. Despite the clinical relevance, the mechanisms underlying the link between chronic pain and myocardial ischemia-reperfusion (MI/R) injury remain poorly understood. This study aimed to investigate the role of the superior cervical ganglion (SCG) in mediating the effects of chronic pain on MI/R injury and to develop a novel therapeutic strategy. We identified that chronic pain upregulated TNF-α expression and induced hyperactivity in SCG sympathetic neurons, exacerbating MI/R injury. To address this, we engineered an injectable Pluronic/alginate-based composite hydrogel loaded with celecoxib and ropivacaine (celecoxib@Laponite-dopamine-alginate-Pluronic F-127@ropivacaine, CLDAFR). This hydrogel was designed to target the SCG, providing a localized and sustained release of the therapeutic agents, thereby mitigating neuronal inflammation and inhibiting neuronal hyperactivity. The CLDAFR hydrogel demonstrated excellent biocompatibility, heat-sensitive gelation properties, and controlled drug release in vitro. In vivo studies showed that applying CLDAFR effectively reduced MI/R injury in a chronic pain model by suppressing TNF-α expression and SCG neuronal activity. In conclusion, the CLDAFR hydrogel represents a promising therapeutic material for treating chronic pain-exacerbated MI/R injury by precisely targeting the SCG and providing a sustained anti-inflammatory and analgesic effect.

Lidocaine Shows Significant Antimicrobial Effects Against Staphylococcus Species: An In-Vitro Study Comparing Different Combinations of Lidocaine and Clinically Used Injectables, like Steroids and Hyaluronan, in the Context of Arthritis Management

INTRODUCTION

Intra-articular injections, commonly used in osteoarthritis treatment, are debated due to their potential link to septic arthritis, though its incidence remains low. Lidocaine, used as a "carrier" for therapeutic substances like hyaluronan or triamcinolone, has pain-relieving and antimicrobial properties. This study investigates the concentration-dependent antimicrobial effects of lidocaine in combination with hyaluronan and triamcinolone in both standard and synovial fluid cultures.

METHODS

The antimicrobial efficacy of lidocaine against Staphylococcus aureus was investigated, with variations in bacterial and lidocaine concentrations. Bacterial growth was monitored using a UV/VIS spectrometer at 600 nm. Lidocaine solutions of 1% and 2% were tested, both alone and in combination with hyaluronic acid or Triam40, in tryptic soy broth (TSB), to reflect knee joint applications. The groups included pure lidocaine (L), Triam (T), hyaluronan (H), and combinations (LT, LH, TH, LTH) with 1% or 2% lidocaine. A bacterial inoculum of 300 CFU/mL was used, and samples were incubated for 12 and 24 h. Additional tests were conducted on Staphylococcus epidermidis and methicillin-resistant Staphylococcus aureus (MRSA), as well as on S. aureus in human synovial fluid.

RESULTS

Lidocaine showed a concentration-dependent antimicrobial effect, with greater inhibition at higher concentrations and lower bacterial densities. All lidocaine-containing combinations significantly reduced the bacterial levels of S. aureus in TSB. Similar results were seen for S. epidermidis and MRSA, with notable inhibition in synovial fluid after 12 h, especially with 2% lidocaine.

CONCLUSIONS

Lidocaine exhibits dose-dependent antimicrobial effects against key pathogens responsible for septic arthritis. Its combination with Triam40 and hyaluronan may reduce the risk of septic arthritis, supporting its clinical relevance.

The Potency of Cytotoxic Mechanisms of Local Anesthetics in Human Chondrocyte Cells

Local anesthetics are commonly used in various clinical settings for both prevention and symptom relief. Numerous clinical studies have demonstrated that intra-articular injections of local anesthetics achieve high success rates in orthopedic practices. However, several widely used local anesthetics, including bupivacaine, lidocaine, and ropivacaine, have been shown to exhibit toxicity to chondrocytes, with the underlying mechanisms of chondrotoxicity remaining poorly understood. In this study, we aimed to investigate the cytotoxic effects of local anesthetics, specifically focusing on the consequences of a single intra-articular injection in human chondrocyte cells. Our results reveal that lidocaine, levobupivacaine, bupivacaine, and ropivacaine induced cell death, characterized by the induction of apoptosis and the suppression of cellular proliferation. These effects were mediated through mechanisms involving oxidative stress, mitochondrial dysfunction, and autophagy pathways. We found that the toxic effects of local anesthetics were concentration-dependent, with lidocaine exhibiting the lowest cytotoxicity among the tested agents in TC28a cells. Notably, bupivacaine and levobupivacaine displayed significant cytotoxic effects related to apoptosis, cellular proliferation, reactive oxygen species generation, mitochondrial membrane potential depolarization, and autophagy in human chondrocyte cells. Our findings not only support existing clinical studies but also highlight potential targets for developing protective agents to mitigate serious side effects associated with their use in orthopedic practices.

Injectable Hydrogel Delivery System with High Drug Loading for Prolonging Local Anesthesia

Peripheral nerve block is performed for precise pain control and lesser side effects after surgery by reducing opioid consumption. Injectable hydrogel delivery systems with high biosafety and moisture content have good clinical application prospects for local anesthetic delivery. However, how to achieve high drug loading and long-term controlled release of water-soluble narcotic drugs remains a big challenge. In this study, heterogeneous microspheres and an injectable gel-matrix composite drug delivery system are designed in two steps. First, heterogeneous hydrogel microspheres loaded with ropivacaine (HMS-ROP) are prepared using a microfluidic chip and in situ alkalization. An injectable self-healing hydrogel matrix (Gel) is then prepared from modified carboxymethylcellulose (CMC-ADH) and oxidized hyaluronic acid (OHA). A local anesthetic delivery system, Gel/HMS-ROP/dexmedetomidine (DEX), with long-term retention and drug release in vivo is prepared by combining HMS-ROP and Gel/DEX. The drug loading of HMS-ROP reached 41.1%, with a drug release time of over 160 h in vitro, and sensory and motor blockade times in vivo of 48 and 36 h, respectively. In summary, the sequential release and synergistic analgesic effects of the two anesthetics are realized using core-shell microspheres, DEX, and an injectable gel, providing a promising strategy for long-acting postoperative pain management.

Impact of gadolinium-based MRI contrast agent and local anesthetics co-administration on chondrogenic gadolinium uptake and cytotoxicity

The gadolinium-based contrast agent DOTA-Gd is clinically used in combination with local anesthetics for direct magnetic resonance arthrography. It remains unclear whether gadolinium uptake into cartilage is influenced by co-administration of bupivacaine or ropivacaine and whether DOTA-Gd alters their chondrotoxicity. Gadolinium quantification of chondrogenic spheroids revealed enhanced gadolinium uptake after simultaneous exposure to local anesthetics. Analyses of the spatial gadolinium distribution using synchrotron X-ray-fluorescence scanning indicates gadolinium exposed chondrocytes. In vitro exposure to DOTA-Gd does not alter viability and proliferation of human chondrocytes and the chondrotoxic potential of the anesthetics. Reduced viability induced by ropivacaine was found to be reversible, while exposure to bupivacaine leads to irreversible cell death. Our data suggest that ropivacaine is more tolerable than bupivacaine and that DOTA-Gd exposure does not alter the cytotoxicity of both anesthetics. Enhanced gadolinium uptake into cartilage due to co-administration of anesthetics should find attention.

FactFinders for patient safety: Preventing local anesthetic-related complications: Local anesthetic chondrotoxicity and stellate ganglion blocks

This series of FactFinders presents a brief summary of the evidence and outlines recommendations to improve our understanding and management of several potential local anesthetic-related complications. Evidence in support of the following facts is presented. (1) Chondrotoxicity: Which Local Anesthetics are Safest for Intraarticular Injection? -- There are drug-, concentration-, and time-dependent chondrotoxic effects that vary between local anesthetics. Current evidence related to commonly used local anesthetics indicates that with exposure to equivalent volumes, bupivacaine, at concentrations of 0.5 % or higher, is the most chondrotoxic agent, while ropivacaine, at concentrations equal to or less than 0.5 %, is the least chondrotoxic in vitro. There is minimal published evidence that confirms these findings in vivo. (2) Minimizing Risks with Stellate Ganglion Blocks -- Evidence suggests that fluoroscopic or ultrasound guidance reduces the risk and increases the accuracy of SGB. Utilizing ultrasound guidance has the added benefit of soft tissue visualization, especially vascular structures, which has the potential to prevent adverse outcomes when compared to the fluoroscopic technique.

Intraarticular Injections in the Foot and Ankle: Medication Selection Patterns and Perceived Risk Of Chondrotoxicity

Background

Intraarticular corticosteroid injections (ICIs) are widely used to treat foot and ankle conditions. Although laboratory studies indicate certain corticosteroids and local anesthetics used in ICIs are associated with chondrotoxic effects, and selected agents such as ropivacaine and triamcinolone may have less of these features, clinical evidence is lacking. We aimed to identify the patterns of drug selection, perceptions of injectate chondrotoxicity, and rationale for medication choice among surgeons in the American Orthopaedic Foot & Ankle Society (AOFAS).

Methods

An e-survey including demographics, practice patterns, and rationale was disseminated to 2011 AOFAS members. Frequencies and percentages were calculated for demographic data, anesthetic and steroid choice, rationale for injectate choice, and perception of chondrotoxicity. Bivariate analysis was used to identify practice patterns significantly associated with perceptions of injectate risk and rationale.

Results

In total, 387 surveys were completed. Lidocaine and triamcinolone were the most common anesthetic and corticosteroid used (51.2% and 39.3%, respectively). Less than half of respondents felt corticosteroids or local anesthetics bear risk of chondrotoxicity. Respondents agreeing that corticosteroids are chondrotoxic were more likely to use triamcinolone (P = .037). Respondents agreeing local anesthetics risk chondrotoxicity were less likely to use lidocaine (P = .023). Respondents choosing a local anesthetic based on literature were more likely to use ropivacaine (P < .001).

Conclusion

Corticosteroid and local anesthetic use in ICIs varied greatly. Rationale for ICI formulation was also variable, as the clinical implications are largely unknown. Those who recognized potential chondrotoxicity and who chose based on literature were more likely to choose ropivacaine and triamcinolone, as reflected in the basic science literature. Further clinical studies are needed to establish guidelines that shape foot and ankle ICI practices based on scientific evidence and reduce the variation identified by this study.

Level of Evidence

Level IV, cross-sectional survey study.

Return to Sport Using Corticosteroid Injections for Knee Pain in Triathletes

Introduction Despite the prevalence of corticosteroid injections in athletes, little is known about their efficacy in triathletes. We aim to assess attitudes, use, subjective effectiveness, and time to return to sport with corticosteroid injections compared to alternative methods in triathletes with knee pain. Methods This is an observational study during the COVID-19 pandemic. Triathletes answered a 13-question survey posted to three triathlon-specific websites. Results Sixty-one triathletes responded, 97% of whom experienced knee pain at some point in their triathlete career; 63% with knee pain received a corticosteroid injection as treatment (average age 51 years old). The most popular attitude (44.3%) regarding corticosteroid injections was "tried them, with good improvement". Most found the cortisone injection helpful for two to three months (28.6%), or more than one year (28.6%); of individuals who found the injections useful for more than one year, four-eight (50%) had received multiple injections during that same period. After injection, 80.6% returned to sport within one month. The average age of people using alternative treatment methods was 39 years old; most returned to sport within one month (73.7%). Compared to alternative methods, there was an ~80% higher odds of returning to sport within one month using corticosteroid injections; however, this relationship was not significant (OR=1.786, p=0.480, 95% CI:0.448-7.09). Conclusion This is the first study to examine corticosteroid use in triathletes. Corticosteroid use is more common in older triathletes and results in subjective pain improvement. A strong association does not exist for a quicker return to sport using corticosteroid injections compared to alternative methods. Triathletes should be counseled on the timing of injections, duration of side effects, and be aware of potential risks.

Effects of local anesthetics and contrast agents on musculoskeletal regenerative medicine procedures

In regenerative medicine, cells, tissues and organs are often replaced, engineered or regrown in order to restore their function after they have been damaged or lost. Local anesthetics, corticosteroids and contrast agents are commonly employed for both diagnostic and therapeutic objectives in interventional pain and musculoskeletal treatments for regenerative medicine. There is growing evidence that routine injectables promote catabolism and disease processes. Thus, understanding the effects of these compounds on regenerative medicine injectates and target tissues such as tenocytes, chondrocytes, nucleus pulposus and ligamentous tissue is critical. This review includes the current research on the effects of local anesthetics and contrast agents, as well as their use and recommendations in regenerative medicine operations.

Management of Patients with Adhesive Capsulitis via Ultrasound-Guided Hydrodilatation without Concomitant Intra-Articular Lidocaine Infusion: A Single-Center Experience

Considering the potential chondrotoxic effects of lidocaine, this retrospective study aimed to examine whether ultrasound-guided hydrodilatation without concurrent lidocaine infusion can still provide comparable treatment benefits for patients with adhesive capsulitis (AC). Outpatient data from 104 eligible AC patients who received ultrasound-guided hydrodilatation between May 2016 and April 2021 were reviewed. A total of 59 patients received hydrodilatation with diluted corticosteroid only, while 45 patients received treatment with mixed, diluted corticosteroid and 1% lidocaine. The overall treatment outcome was documented as the percentage of clinical improvement, ranging from 0% to 100% compared to baseline, and it was ranked into poor, moderate and good treatment outcomes. The results show no significant group-wise difference in demographics, overall treatment outcome, and number of hydrodilatations, while most patients showed moderate and good treatment outcomes. Patients with lidocaine infusion did not show greater treatment benefit. Our results suggest that ultrasound-guided hydrodilatation without concurrent lidocaine infusion can still deliver good treatment benefits for AC patients, and the findings are supportive of a modified approach toward careful intra-articular local anesthetic use during management of AC in the primary care setting.

Combine Approach of Proximal Fibula Osteotomy (PFO) Followed by Intra-Articular Dextrose Prolotherapy in Severe Medial Knee Osteoarthritis

Background

Knee osteoarthritis (OA) is a chronic and progressive degenerative disease. It resulted from mechanical and chemical disorders that damage the joint and the underlying bone. The management of knee OA is challenging due to poor self-regeneration of connective tissues. Surgical treatment with prolotherapy approaches was conducted to treat medial compartment knee OA.

Aim

To know the injection frequency to reach a 50% improvement in VAS score and WOMAC index.

Methods

Six patients who suffered from late-stage medial compartment knee OA underwent PFO followed by twelve sessions of intra-articular dextrose prolotherapy. The subjective pain score, visual analog scale (VAS), was assessed based on the patient subjectiveness before and after treatment. Patients marked the score from 0 to 10 cm to describe the current pain state. The functional index, the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) index used to evaluate the Patient's clinical symptoms. It ranges from 0 to 96 points consisting of three main sections: pain (total 20 points), stiffness (total: eight points), and physical function disability (total 68 points). Higher scores indicate severe symptoms and function.

Results

Four patients showed pain relief and functional improvement with more than 50% scores of VAS and WOMAC after the treatment. Two patients received more than twelve doses of intra-articular dextrose prolotherapy due to a lack of progress.

Conclusion

This study provides clinical evidence for a new treatment strategy for advanced knee OA. This combined therapy improves the patient's daily activity function and postpones the need for total knee arthroplasty (TKA).

Intra-articular triamcinolone hexacetonide injections in hands osteoarthritis ‒ A double-blinded randomized controlled trial with a one year follow-up

OBJECTIVE

to evaluate the effectiveness of triamcinolone Hexacetonide (TH) Intra-Articular Injection (IAI) in hand Interphalangeal Joints (IP) of Osteoarthritis (OA) patients to improve pain and joint swelling; improve function, goniometry, and grasping force, and assess IAI influence on radiographic evolution over 1-year.

METHODS

A randomized, double-blind study. 60 patients who underwent IAI at the most symptomatic IP joint were randomly assigned to receive TH+Lidocaine (LD) (TH/LD group) or just LD (LD group). Patients were assessed blindly for 1-year, at baseline and 1, 4, 8, 12, and 48 weeks. The following variables were assessed: articular pain and swelling, AUSCAN and COCHIN functional questionnaires, grip and pinch strength, goniometry, perception of improvement, acetaminophen consumption, and simple radiography. Repeated-measures ANOVA test was used to analyze the intervention response.

RESULTS

Sixty patients completed the follow-up. There were nine missed assessments. 97% were women; mean age of 61-years (SD = 8.2), and approximately 5-years of disease (SD = 3.6). Half of the patients present radiographic classification Kellgren and Lawrence (KL) grades I and II, and the other half grades III and IV. The two groups evolved similarly at 48-weeks. TH/LD group had a better evaluation in joint swelling and acetaminophen consumption (p = 0.04 and p < 0.001, respectively) at 48-weeks. Radiographically there was no statistical difference between groups (KL, p = 0.564; erosive OA, p = 0.999; worsening, p = 0.573).

CONCLUSION

The IAI IP hands OA is effective for the improvement of joint swelling and decrease of analgesic consumption and does not influence the radiographic evolution of the injected joint.

Effect of local anesthetics on platelet physiology and function

Local anesthetics are often used at the site of injury or mixed with platelet-rich plasma to reduce pain when treating orthopedic and sports-related injuries. Local anesthetics have been shown to have deleterious effects on stromal cells, but their impact on platelets has not been investigated. In this study, we aimed to assess the effects of lidocaine, bupivacaine, and ropivacaine on platelet health. Based on the deleterious effects of local anesthetics on nucleated cells, we hypothesized that these compounds would affect platelet viability, intracellular physiology, and function. Platelet preparations were derived from randomly selected donors and exposed to lidocaine 1%, bupivacaine 0.75%, ropivacaine 0.5%, and saline at 1:1 and 1:3 ratios. Platelet morphology, viability, intracellular calcium, production of radical oxygen species (ROS), apoptosis, and adhesion were assessed via fluorescent microscopy and flow cytometry. Bupivacaine resulted in increased ROS production, calcium dysregulation, apoptosis, and reduced platelet adhesion. By contrast, ropivacaine and lidocaine were similar to saline in most assays, except for a low degree of mitochondrial stress as evidenced by increased ROS production. Ultimately, bupivacaine 0.75% was harmful to platelets as evidenced by reduced platelet viability, adhesion, and increased apoptosis, whereas lidocaine 1% and ropivacaine 0.5% were relatively safe at the 1:1 and 1:3 dilutions. Clinical significance: Lidocaine 1% and ropivacaine 0.5% can be used at up to a 1:1 ratio with platelet preparations to reduce the pain and discomfort of PRP procedures while maintaining platelet therapeutic potential.

The Influence of a Single Intra-Articular Lidocaine Injection on the Viability of Articular Cartilage in the Knee

OBJECTIVE

To evaluate the in vivo effect of a single intra-articular injection of local anesthetic (LA) lidocaine on the viability of articular cartilage in the intact or osteoarthritic (OA) human knees, and to measure the synovial postinjection concentration of lidocaine in the knee.

DESIGN

This study includes 3 interconnected experiments: (A) Synovial LA concentration measurement after a 2% lidocaine injection before knee arthroscopy in 10 patients by liquid chromatography-tandem mass spectrometry (LC-MS/MS). (B) Human osteochondral explants (N = 27) from intact knees procured at autopsies were incubated for different time intervals (30 minutes, 2 hours, 24 hours) with 2% lidocaine, 0.04% lidocaine (measured), or culture medium (control), and later evaluated for cell viability by LIVE/DEAD staining. (C) Ten out of 19 matched patients scheduled for knee replacement received a single intra-articular injection of 2% lidocaine approximately 30 minutes prior to the procedure; 9 patients served as control. Osteochondral samples with OA changes were harvested during surgery and analyzed for chondrocyte viability by LIVE/DEAD staining.

RESULTS

(A) The synovial LA concentration was significantly lower than the primary concentration injected: average 0.23 mg/mL (0.02%), highest measured 0.37 mg/mL (0.04%). (B) In vitro exposure to a reduced LA concentration had no significant influence on chondrocyte viability in intact cartilage explants (24-hour averages: control, 93%; 0.04% lidocaine, 92%; 2% lidocaine, 79%). (C) Viability of chondrocytes in OA knees was similar between 2% lidocaine injection (85%) and control (80%).

CONCLUSIONS

A single intra-articular knee injection of 2% lidocaine did not influence the chondrocyte viability neither in healthy nor in OA cartilage. A fast postinjection reduction of synovial LA concentration (more than 40 times) is the most likely protective mechanism.

Safety of Intra-articular Hip Corticosteroid Injections: A Matched-Pair Cohort Study

Background

Recent studies have suggested there is an increased risk of avascular necrosis (AVN), subchondral insufficiency fracture (SIF), femoral head collapse, and osteoarthritis (OA) progression in the 12-month period after hip corticosteroid/anesthetic injection (CSI); however, these studies have failed to account for preinjection OA severity or preexisting AVN/SIF.

Purpose

To compare these complication rates in patients treated with versus without hip CSI, while minimizing the aforementioned forms of selection bias present in previous investigations.

Study Design

Cohort study; Level of evidence, 3.

Methods

For all patients who had undergone a single hip CSI and hip magnetic resonance imaging (MRI) within the preceding 12 months at a single institution (CSI cohort), 2 musculoskeletal radiologists retrospectively graded OA severity (modified Kellgren-Lawrence classification) and femoral head collapse on hip radiographs taken within 12 months before, and 1 to 12 months after, CSI. Using identical methodology, radiographs from a control cohort (composed of hips that had never undergone CSI and had undergone hip MRI with hip radiographs taken within 12 months before, and 1-12 months after, MRI) were also graded. The cohorts were matched for age, sex, body mass index, and OA severity. Readers were blinded to cohort and time point. OA progression was defined as an increase in modified Kellgren-Lawrence grade ≥1 between radiographs.

Results

Included were 141 matched pairs. After exclusion of 48 matched pairs with at least 1 incidence of preexisting AVN or SIF on index MRI, CSI (n = 93; mean time between CSI and final hip radiograph, 5.43 months) and control (n = 93; mean time between MRI and final hip radiograph, 4.87 months), groups did not significantly differ in rates of OA progression (3.2% vs 3.2%) or new femoral head collapse (3.2% vs 2.2%).

Conclusion

In contrast to the findings of recent retrospective investigations, we did not find that patients treated with hip CSI had significantly higher rates of short-term OA progression or femoral head articular surface collapse after controlling for baseline OA severity and preexisting AVN or SIF. Future randomized trials investigating safety of hip CSI are needed to determine its exact short-term risk profile.

Permeable spaces between glenohumeral ligaments as potential gateways for rapid regional anesthesia of the shoulder

Shoulder pain is a highly prevalent condition, often resulting in major life limitations, and requiring effective treatments. In this work, we explore the anatomical basis of a proposed approach to the regional anesthesia of the shoulder through a single injection under the subscapularis muscle. Bilateral experimental injections in shoulders from body donors (Radiolar ® and Methylene-Blue) under the subscapular muscle (n = 11) and cadaveric systematic dissections of other 35 shoulders from body donors were performed. Injectate spread was then qualitatively assessed. Long axis of permeable foramina in the anterior aspect of the shoulder joint capsule was measured in centimeters using a digital caliper. More than 40% of specimens had at least one permeable space (Weitbrech and/or Rouvière foramina) communicating the subscapular bursa and the articular space. We further demonstrate that an ultrasonography-guided injection under the subscapularis muscle allows the spread of the injectate through the anterior, inferior and posterodorsal walls of the articular capsule, the subacromial bursa, and the bicipital groove, as well as into the articular space for some injections. The odds of accidental intraarticular injection decrease when injecting with low volumes. This anatomical study provides a detailed description of foramina between glenohumeral ligaments. Furthermore, the data shown in this work supports, as a proof of concept, a safe alternative for rapid and specific blockade of terminal sensory branches innervating the shoulder joint capsule.

In Vitro Effects of Bupivacaine on the Viability and Mechanics of Native and Engineered Cartilage Grafts

BACKGROUND

Although the toxic effects of bupivacaine on chondrocyte monolayer culture have been well described, its cellular and mechanical effects on native and engineered articular cartilage remain unclear. For the repair of articular cartilage defects, fresh autologous and allogenic cartilage grafts are commonly used, and engineered cell-based therapies are emerging. The outcome of grafting therapies aimed at repairing damaged cartilage relies largely on maintaining proper viability and mechanical suitability of the donor tissues.

PURPOSE

To investigate the in vitro effects of single bupivacaine exposure on the viability and mechanics of 2 cartilage graft types: native articular cartilage and engineered neocartilage.

STUDY DESIGN

Controlled laboratory study.

METHODS

Articular cartilage explants were harvested from the bovine stifle femoral condyles, and neocartilage constructs were engineered from bovine stifle chondrocytes using the self-assembling process, a scaffold-free approach to engineer cartilage tissue. Both explants and neocartilage were exposed to chondrogenic medium containing a clinically applicable bolus of 0.5%, 0.25%, or 0% (control) bupivacaine for 1 hour, followed by fresh medium wash and exchange. Cell viability and matrix content (collagen and glycosaminoglycan) were assessed at t = 24 hours after treatment, and compressive mechanical properties were assessed with creep indentation testing at t = 5 to 6 days after treatment.

RESULTS

Single bupivacaine exposure was chondrotoxic in both explants and neocartilage, with 0.5% bupivacaine causing a significant decrease in chondrocyte viability compared with the control condition (55.0% ± 13.4% vs 71.9% ± 13.5%; P < .001). Bupivacaine had no significant effect on matrix content for either tissue type. There was significant weakening of the mechanical properties in the neocartilage when treated with 0.5% bupivacaine compared with control, with decreased aggregate modulus (415.8 ± 155.1 vs 660.3 ± 145.8 kPa; P = .003), decreased shear modulus (143.2 ± 14.0 vs 266.5 ± 89.2 kPa; P = .002), and increased permeability (14.7 ± 8.1 vs 6.6 ± 1.7 × 10^-15 m⁴/Ns; P = .009). Bupivacaine exposure did not have a significant effect on the mechanical properties of native cartilage explants.

CONCLUSION

Single bupivacaine exposure resulted in significant chondrotoxicity in native explants and neocartilage and significant weakening of mechanical properties of neocartilage. The presence of abundant extracellular matrix does not appear to confer any additional resistance to the toxic effects of bupivacaine.

CLINICAL RELEVANCE

Clinicians should be judicious regarding the use of intra-articular bupivacaine in the setting of articular cartilage repair.

Effect of bupivacaine concentration and formulation on canine chondrocyte viability in vitro

OBJECTIVE

To quantitate bupivacaine concentration and formulation effects on chondrocyte viability in vitro.

STUDY DESIGN

Controlled laboratory study.

SAMPLE POPULATION

Primary canine chondrocyte isolates.

METHODS

Cell passage 3 and 4 canine chondrocytes were exposed to 0.9% saline; canine chondrocyte growth medium; 0.4, 0.5, 0.6, 1.5, 2.5, 3.5, or 5 mg/mL preservative-free standard formulation bupivacaine (SFB); or 13.3 or 6.65 mg/mL liposomal encapsulated bupivacaine (LEB) for 1 hour. Chondrocyte viability and clonogenicity were quantitated with 3-(4,5-dimethylthiazol-2-31 yl)-2,5-diphenyltetrazolium bromide (MTT) and clonogenic assays, respectively. Differences among concentrations and formulations were assessed with Kruskal-Wallis and Dwass-Steel-Critchlow-Fligner post hoc tests.

RESULTS

Growth medium had the highest cell viability based on MTT metabolism. Similarly, all LEB concentration groups had higher cell viability compared with SFB concentration cells treated with 3.5 or 5 mg/mL SFB (P < .03). Among SFB concentrations, cell viability was higher at 0.6 mg/mL compared with at 2.5 mg/mL or greater (P < .03). Cell clonogenicity was not significantly different between saline, culture medium, or 0.5 mg/mL SFB. Clonogenicity was lower with all tested LEB concentrations compared with saline or medium (P < .02).

CONCLUSION

In vitro toxicity of SFB on canine chondrocytes is concentration dependent. Liposomal encapsulated bupivacaine may have time-dependent effects resulting in chondrotoxicity.

CLINICAL SIGNIFICANCE

Clinically relevant concentrations of SFB after a single injection may not result in chondrotoxic effects in vitro. Liposomal encapsulated bupivacaine should not be used in the articular environment.

Differences in Cytotoxicity of Lidocaine, Ropivacaine, and Bupivacaine on the Viability and Metabolic Activity of Human Adipose-Derived Mesenchymal Stem Cells

PURPOSE

We evaluated biological effects of distinct local anesthetics on human adipose-derived mesenchymal stem cells when applied to reduce periprocedural pain during mesenchymal stem cell injections.

METHODS AND MATERIALS

Metabolic activity (MTS assay), viability (Live/Dead stain), and gene expression (quantitative real-time reverse-transcriptase polymerase chain reaction) were measured in mesenchymal stem cells incubated with various concentrations of lidocaine, ropivacaine, or bupivacaine during a 12-hr time course.

RESULTS

Cell viability and metabolic activity decreased in a dose, time, and substance-specific manner after exposure to lidocaine, ropivacaine, and bupivacaine, with ropivacaine being the least cytotoxic. Cell viability decreases after brief exposure (<1.5 hrs) at clinically relevant concentrations (eg, 8 mg/ml of lidocaine, 2.5 mg/ml of ropivacaine or bupivacaine). Mesenchymal stem cells exposed to local anesthetics change their expression of mRNA biomarkers for stress response (EGR1, EGR2), proliferation (MKI67, HIST2H4A), ECM (COL1A1, COL3A1), and cell surface marker (CD105).

CONCLUSIONS

Local anesthetics are cytotoxic to clinical-grade human mesenchymal stem cells in a dose-, time-, and agent-dependent manner and change expression of ECM, proliferation, and cell surface markers. Lidocaine and bupivacaine are more cytotoxic than ropivacaine. Single-dose injections of local anesthetics may affect the biological properties of mesenchymal stem cells in vitro but may not affect the effective dose of MSCs in a clinical setting.

How does intraarticular dexmedetomidine injection effect articular cartilage and synovium? An animal study

Background

Intraarticular injections are widely used to provide pain relief after arthroscopic procedures and minimize the use of opioids. Dexmedetomidine has been proven to potentiate pain relief and postpone the demand for the first analgesic drug when it is used intraarticularly following arthroscopic knee procedures. However, the effects of dexmedetomidine on articular structures have not yet been evaluated. Our aim was to determine the effects of intraarticular dexmedetomidine injection on articular structures such as cartilage and synovium.

Design

Animal study.

Methods

Twenty adult rats (Sprague-Dawley) were enrolled in the study. Following appropriate aseptic and anesthetic conditions, dexmedetomidine (100 mcg/ml) (0.25 ml) was injected into the right knee joint (the study group) and normal saline solution (0.25 ml) into the left knee joint (the control group) of the rats. Four rats were sacrificed from each group on days 1, 2, 7, 14, and 21, and knee joint samples were obtained. Histologists evaluated the articular and periarticular regions and the synovium using histological sections, and a five-point scale was used to grade the inflammatory changes in a blinded manner.

Results

The groups were found to be similar in terms of median congestion scores, edema and inflammation scores, subintimal fibrosis, neutrophil activation and cartilage structure at each of the time intervals.

Conclusion

In our placebo-controlled, in vivo trial, the intraarticular use of dexmedetomidine seemed to be safe with respect to the studied histopathological parameters. However, complementary studies investigating the histopathological effects, analgesic dosage and adverse effects of dexmedetomidine on damaged articular structure models are needed.

Return to Sports After Joint Preservation Hip Surgery

Femoroacetabular impingement results from a mismatch of congruency between the femoral head and the acetabulum. This condition is most common among young, active patients and may lead to pain, decreased quality of life, and inability to participate in athletics. Hip preservation surgery is widely performed is used as a definitive treatment option in athletes at all levels of competition. Athletes have reported high rates of return to play and satisfaction and expect rehabilitation to require approximately 4 to 6 months. This article provides an overview of femoroacetabular impingement, including diagnosis and treatment, with focus on athletes and return to play.

Corticosteroid and Local Anesthetic Use Trends for Large Joint and Bursa Injections: Results of a Survey of Sports Medicine Physicians

BACKGROUND

Physician decision-making surrounding choices for large joint and bursa injections is poorly defined, yet influences patient safety and treatment effectiveness.

OBJECTIVE

To identify practice patterns and rationale related to injectate choices for large joint and bursal injections performed by physician members of the American Medical Society for Sports Medicine (AMSSM).

DESIGN

An electronic survey was sent to 3400 members of the AMSSM. Demographic variables were collected: primary specialty (residency), training location, practice location, years of clinical experience, current practice type, and rationale for choosing an injectate.

PARTICIPANTS

A total of 674 physicians responded (minimum response rate of 20%).

INTERVENTION

Not applicable.

MAIN OUTCOME MEASURES

Outcomes of interest included corticosteroid type and dose, local anesthetic type, and total injectate volume for each large joint or bursa (hip, knee, and shoulder).

RESULTS

Most respondents used triamcinolone (50% to 56% of physicians, depending on injection location) or methylprednisolone (25% to 29% of physicians), 21 to 40 mg (53% to 60% of physicians), diluted with lidocaine (79% to 87%) for all large joint or bursa injections. It was noted that 36.2% (244/674) of respondents reported using >40 mg for at least one injection type. Most (90.5%, 610/674) reported using an anesthetic other than ropivacaine for at least one type of joint or bursa injection. Physicians who reported lidocaine use were less likely to report that their injectate choice was based on the literature that they reviewed (odds ratio [OR] 0.41 [0.27-0.62], P < .001). Respondents predominantly used 5 to 7 mL of total injectate for all large joints or bursae (45% to 54% of respondents), except for the pes anserine bursa, where 3-4 mL was more common (51% of physicians).

CONCLUSIONS

It appears that triamcinolone and methylprednisolone are the most commonly used corticosteroids for sports medicine physicians; most physicians use 21 to 40 mg of corticosteroid for all injections, and lidocaine is the most-often used local anesthetic; very few use ropivacaine. Over one-third of respondents used high-dose (>40 mg triamcinolone or methylprednisolone) for at least one joint or bursa.

Chondrotoxicity of Local Anesthetics: Liposomal Bupivacaine Is Less Chondrotoxic than Standard Bupivacaine

Objective

The purpose of this study is to determine whether (1) liposomal bupivacaine is chondrotoxic; (2) the chondrotoxicity of liposomal bupivacaine differs from standard bupivacaine; and (3) chondrotoxic effects are time dependent.

Materials and Methods

We obtained 72 10 mm articular cartilage plugs from 12 fresh bovine distal femoral knee joints and exposed them to either saline, 0.5% bupivacaine, or liposomal bupivacaine for either 30 or 90 minutes. Twenty-four hours after treatment, chondrocyte viability was measured with the use of a fluorescent live/dead assay. An ANOVA test of variance was performed followed by a Holm-Sidak test to make pairwise comparisons across conditions. Student's t-test was used to compare means.

Results

Percent viability of cells exposed to liposomal bupivacaine for 30 minutes was less versus saline control (53.9% ± 21.5% vs. 73.7 ± 18.4%, p=0.035), and this remained significant at 90 minutes (49.1% ± 20.3% vs. 67.2% ± 25.6%, p < 0.001). Liposomal bupivacaine had less chondrotoxic effects when compared with bupivacaine after 90 minutes, with greater viability (49.1% ± 20.3% vs. 21.4% ± 14.0%, p=0.003). Chondrotoxicity was found to be time dependent within the bupivacaine group (percent viability at 30 min: 45.5 ± 18.2%, 90 min: 21.4 ± 14.0%, p=0.001); however, liposomal bupivacaine did not demonstrate a significant time-dependent chondrotoxic relationship (p=0.583).

Conclusions

Bupivacaine and liposomal bupivacaine are both toxic to chondrocytes. Liposomal bupivacaine is less chondrotoxic than standard bupivacaine and does not demonstrate a time-dependent toxicity.

Orthobiologics for the Hip Region: A Narrative Review

Management of hip region disorders is challenging. Orthobiologic treatments including platelet rich plasma (PRP), mesenchymal stem cells, and amniotic injectables have gained popularity as promising treatments despite a lack of robust evidence for their effectiveness. We review rationale and current evidence for orthobiologics for three common hip region conditions: hip osteoarthritis, gluteal tendinopathy, and proximal hamstring tendinopathy. Overall, the current state of evidence is extremely limited for orthobiologic treatments and is predominantly relevant to PRP injections. There is currently a lack of data to support the use of mesenchymal stem cells or amniotic injectables in these conditions of the hip.

Treatment of Osteoarthritis Secondary to Developmental Dysplasia of the Hip with Prolotherapy Injection versus a Supervised Progressive Exercise Control

BACKGROUND Osteoarthritis secondary to developmental dysplasia of the hip (DDH) is one of the major causes of hip pain and disability. The aim of the study was to compare the effectiveness of prolotherapy (PrT) injections versus exercise protocol for the treatment of DDH. MATERIAL AND METHODS There were 46 hips of 41 patients who had osteoarthritis secondary to DDH included in this study. Patients were divided into 2 groups: treated with PrT (PrT group; n=20) and exercise (control group; n=21). Clinical outcomes were evaluated with visual analog scale for pain (VAS) and Harris hip score (HHS) at baseline, 3 weeks, 3 months, 6 months, and a minimum of 1-year follow-up. In PrT group clinical results were also compared in Crowe type I-IV hips. RESULTS Between group analysis revealed no significant between group differences at baseline. Dextrose injection recipients out performed exercise controls for VAS pain change score at 6 months (-4.6±2.6 versus -2.8±2.5; P=0.016), and 12 months (-4.5±2.4 versus -2.9±2.5; P=0.017) and for HHS at 6 months (24.2±14.0 versus 14.8±12.4; P=0.007) and 12 months (24.3±13.4 versus 16.5±11.3; P=0.018). CONCLUSIONS To our best knowledge, this study is the first regarding the effects of an injection method in the treatment of osteoarthritis secondary to DDH. According to our study, PrT is superior to exercises. PrT could provide significant improvement for clinical outcomes in DDH and might delay surgery.

Risks and Complications Associated With Intra-articular Arthroscopy of the Knee and Shoulder in an Office Setting

BACKGROUND

Classically, arthroscopy has been considered one of the diagnostic gold standards for assessing intra-articular knee and shoulder abnormality.

PURPOSE

To assess the risks associated with in-office needle arthroscopy.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A retrospective case series analysis was performed by evaluating consecutive diagnostic needle arthroscopies performed by 13 physicians at 13 independent institutions. The findings of both major and minor complications were reported by each of the 13 surgeons based on office documentation. The data were analyzed as a lump sum of both knee and shoulder cases and then subdivided and examined separately. The patients' ages ranged from 14 to 78 years, and no statistical difference was noted between the numbers of men and women. A major complication was defined as infection, chondral toxicity, or the need for alternative treatment at an urgent care or emergency room secondary to the procedure. Minor complications were defined as a vasovagal event, pain that persisted after 24 hours, or the need for crutches or sling postprocedure.

RESULTS

Of the 1419 cases, no major complications were reported. The overall rate of vasovagal events was 1.9% for all procedures (1.6% in knees, 3% in shoulders). Persistent pain longer than 24 hours postprocedure was reported in 0.3% of cases. No patient required crutches or a sling. Postarthroscopy magnetic resonance imaging was needed in 1.4% of cases. No device failures were reported.

CONCLUSION

Previous literature has evaluated the efficacy, sensitivity, and specificity of in-office diagnostic arthroscopy, and this study validates needle arthroscopy as safe in the office setting, with minimal risk of major or minor complications.

Effect of different anaesthetic techniques on gene expression profiles in patients who underwent hip arthroplasty

Objectives

To investigate the modulation of genes whose expression level is indicative of stress and toxicity following exposure to three anaesthesia techniques, general anaesthesia (GA), regional anaesthesia (RA), or integrated anaesthesia (IA).

Methods

Patients scheduled for hip arthroplasty receiving GA, RA and IA were enrolled at Rizzoli Orthopaedic Institute of Bologna, Italy and the expression of genes involved in toxicology were evaluated in peripheral blood mononuclear cells (PBMCs) collected before (T0), immediately after surgery (T1), and on the third day (T2) after surgery in association with biochemical parameters.

Results

All three anaesthesia methods proved safe and reliable in terms of pain relief and patient recovery. Gene ontology analysis revealed that GA and mainly IA were associated with deregulation of DNA repair system and stress-responsive genes, which was observed even after 3-days from anaesthesia. Conversely, RA was not associated with substantial changes in gene expression.

Conclusions

Based on the gene expression analysis, RA technique showed the smallest toxicological effect in hip arthroplasty.

Trial registration

ClinicalTrials.gov number NCT03585647.

Local Anesthetics' Toxicity toward Human Cultured Chondrocytes: A Comparative Study between Lidocaine, Bupivacaine, and Ropivacaine

OBJECTIVE

In orthopedic joint injection, the most frequently used local anesthetics are ropivacaine, bupivacaine, and 1% or 2% lidocaine. The aim of this study was to examine effects of these various anesthetics on the viability of human chondrocytes. Our hypothesis was that all local anesthetics tested damage human chondrocytes in vitro.

METHODS

Primary human chondrocytes were isolated and cultured from 6 donated human knee joints (mean age of donors 61.2 years). Local anesthetics were added to these cultures. Toxicity analysis was performed by visualization of cell structure using light microscopy. Determination of vital chondrocytes was performed by use of a Casy cell counter. Chondrocytes' cell death was examined by fluorescence microscopy and an XTT ELISA assay.

RESULTS

Light microscope and fluorescence microscope data revealed a defect cell structure and increased number of dead cells after addition of 1% or 2% lidocaine and bupivacaine but not ropivacaine. We were able to show an increased level of XTT activity after treatment with bupivacaine, 2% lidocaine or ropivacaine. The count of vital chondrocytes was significantly decreased after treatment with bupivacaine, 1% or 2% lidocaine, and ropivacaine.

CONCLUSIONS

The data show that treatment with local anesthetics induces cell damage of human chondrocytes in vitro. Ropivacaine seems to be a local anesthetic with the lowest toxic potential on human chondrocytes, a feature that may favor its preference for use in joint injection.

Ultrasound-Guided Hip Injections

The diagnosis of hip pain can be difficult to isolate because the discomfort can originate from several locations and compensatory pain patterns. Pain generators can include the intra- and extra-articular hip structures, the lumbar spine, the pelvic floor, or a combination of these. It can also be referred as pain from the bowel, bladder, or reproductive organs. Injections into and around the hip have become an important part of both diagnostic and nonsurgical treatment algorithm for hip pain. The proximity of the hip to important neurovascular structures, lack of palpable anatomic landmarks, and deep location of targets can make use of ultrasonography-guided injections ideal. These injections have been growing in popularity in the orthopedic community because ultrasonography allows for a real-time visualization of dynamic anatomy without any radiation exposure to the patient and physician. The use of ultrasonography has allowed for in-office image guidance with improved accuracy for more targeted and advanced procedures. The patient's response to these injections can help guide patient selection for surgery and allow for better pain control of the soft-tissue pathology that often accompanies intra-articular pathology. This article highlights the diagnostic and therapeutic value of ultrasonography-guided hip injections for an orthopedic practice. The focus is on sonographic anatomy, introduction to technique, common indications, and pearls and pitfalls of these procedures.

Absence of cytotoxic and inflammatory effects following in vitro exposure of chondrogenically-differentiated human mesenchymal stem cells to adenosine, lidocaine and Mg2+ solution

Background

ALM solution, a combination of adenosine, lidocaine and Mg²⁺, is an emerging small volume therapy that has been shown to prevent and correct coagulopathy and surgery-related inflammation in preclinical models, though its application in orthopaedic surgery is yet to be demonstrated. The effect of ALM solution on chondrocytes is unknown. The aim of this preliminary study was to investigate the effect of ALM solution on viability and inflammatory responses of chondrogenically-differentiated human bone marrow-derived mesenchymal stem cells (chondro-MSC), in vitro.

Methods

Chondro-MSC were exposed to media only, saline (0.9% NaCl or 1.3% NaCl) only, or saline containing ALM (1 mM adenosine, 3 mM lidocaine, 2.5 mM Mg²⁺) or tranexamic acid (TXA, 100 mg/ml) for 1 or 4 h. Responses to ALM solutions containing higher lidocaine concentrations were also compared. Chondrocyte viability was determined using WST-8 colorimetric assays and inflammatory cytokine (TNF-α, IL-1β, IL-8) and matrix metalloproteinases (MMP-3, MMP-12, MMP-13) concentrations using multiplex bead arrays.

Results

The viability of chondro-MSC was significantly greater after 1 h treatment with ALM compared to saline (96.2 ± 7.9 versus 75.6 ± 7.3%). Extension of exposure times to 4 h had no significant adverse effect on cell viability after treatment with ALM (1 h, 85.4 ± 5.6 v 4 h, 74.0 ± 15.2%). Cytotoxicity was evident following exposure to solutions containing lidocaine concentrations greater than 30 mM. There were no significant differences in viability (80 ± 5.4 v 57.3 ± 16.2%) or secretion of IL-8 (60 ± 20 v 160 ± 50 pg/ml), MMP-3 (0.95 ± 0.6 v 3.4 ± 1.6 ng/ml), and MMP-13 (4.2 ± 2.4 v 9.2 ± 4.3 ng/ml) in chondro-MSC exposed to saline, ALM or TXA.

Conclusions

Short-term, in vitro exposure to clinically-relevant concentrations of ALM solution had no adverse inflammatory or chondrotoxic effects on human chondro-MSC, with responses comparable to saline and TXA. These findings provide support for continued evaluation of ALM solution as a possible therapeutic to improve outcomes following orthopaedic procedures.

Protective effects of platelet-rich plasma against lidocaine cytotoxicity on canine articular chondrocytes

Background

Lidocaine (LD) is one of the most commonly used local anesthetics for performing arthroscopic surgery and managing of osteoarthritic pain in both human and veterinary medicine. However, over the last years, several studies have focused on the chondrotoxic effects of LD. In order to ensure that intra-articular lidocaine is safe to use, treatments aimed at mitigating chondrocyte death have recently been investigated. The aim of this study is to evaluate the possible protective effects of platelet-rich plasma (PRP) against LD cytotoxicity on canine articular chondrocytes.

Results

Articular canine chondrocytes, were exposed to 1% or 1.8% LD alone or in co-presence with 10% PRP for 30 min. In order to evaluate the effects of PRP pre-treatments, experiments were carried out on cells cultured in serum-free medium-or in medium supplemented with 10% PRP or 10% fetal bovine serum. Cell viability was evaluated by methyl thiazolyl tetrazolium assay and cell apoptosis was analyzed by flow cytometry using annexin V-fluorescein isothiocyanate/propidium iodide. The results showed that LD significantly reduced canine chondrocytes viability, probably due to apoptosis induction. Pre-treatment or the co-presence of PRP in the media restored the number of viable chondrocytes. The PRP also seemed to protect the cells from LD-induced apoptosis.

Conclusions

Pre-treatments and/or the simultaneous administration of PRP reduced LD-induced cytotoxicity in canine chondrocytes. Further in vivo studies are required to determine whether PRP can be used as a save protective treatment for dogs receiving intra-articular LD injections.

Injectable nanocomposite analgesic delivery system for musculoskeletal pain management

Musculoskeletal pain is a major health issue which results from surgical procedures (i.e. total knee and/or hip replacements and rotator cuff repairs), as well as from non-surgical conditions (i.e. sympathetically-mediated pain syndrome and occipital neuralgia). Local anesthetics, opioids or corticosteroids are currently used for the pain management of musculoskeletal conditions. Even though local anesthetics are highly preferred, the need for multiple administration presents significant disadvantages. Development of unique delivery systems that can deliver local anesthetics at the injection site for prolonged time could significantly enhance the therapeutic efficacy and patient comfort. The goal of the present study is to evaluate the efficacy of an injectable local anesthetic nanocomposite carrier to provide sustained analgesic effect. The nanocomposite carrier was developed by encapsulating ropivacaine, a local anesthetic, in lipid nanocapsules (LNC-Rop), and incorporating the nanocapsules in enzymatically crosslinked glycol chitosan (0.3GC) hydrogels. Cryo Scanning Electron Microscopic (Cryo SEM) images showed the ability to distribute the LNCs within the hydrogel without adversely affecting their morphology. The study demonstrated the feasibility to achieve sustained release of lipophilic molecules from the nanocomposite carrier in vitro and in vivo. A rat chronic constriction injury (CCI) pain model was used to evaluate the efficacy of the nanocomposite carrier using thermal paw withdrawal latency (TWL). The nanocomposite carriers loaded with ropivacaine and dexamethasone showed significant improvement in pain response compared to the control groups for at least 7 days. The study demonstrated the clinical potential of these nanocomposite carriers for post-operative and neuropathic pain.

STATEMENT OF SIGNIFICANCE

Acute or chronic pain associated with musculoskeletal conditions is considered a major health issue, with healthcare costs totaling several billion dollars. The opioid crisis presents a pressing clinical need to develop alternative and effective approaches to treat musculoskeletal pain. The goal of this study was to develop a long-acting injectable anesthetic formulation which can sustain a local anesthetic effect for a prolonged time. This in turn could increase the quality of life and rehabilitation outcome of patients, and decrease opioid consumption. The developed injectable nanocomposite demonstrated the feasibility to achieve prolonged pain relief in a rat chronic constriction injury (CCI) model.

Procaine and saline have similar effects on articular cartilage and synovium in rat knee

Background

Intra-articular local anaesthetics are widely used for providing postoperative analgesia and decreasing the need for opioids. Procaine has proven positive effects in carpal tunnel syndrome and chondromalacia patella. However, the effect of procaine on articular cartilage has not yet been studied. The aim of this study was to evaluate the effects of intra-articular procaine injection on the articular cartilage and the synovium.

Methods

Twenty adult Sprague-Dawley rats were enrolled in the study. After providing anaesthesia and aseptic conditions, 0.25 ml of 10% procaine was injected to the right knee joint, and 0.25 ml of normal saline (as control group) was injected to the left knee joint. Knee joint samples were obtained from four rats in each group after appropriate euthanasia on days 1, 2, 7, 14 and 21. The histological sections of the articular and periarticular regions and the synovium were evaluated by two histologists, and inflammatory changes were graded according to a five-point scale in a blinded manner. The apoptosis of chondrocytes was determined by the caspase-3 indirect immunoperoxidase method.

Results

There were no significant differences in inflammation between procaine and saline groups at any of the time intervals. Slight inflammatory infiltration due to injection was seen in both groups on the 1st day. Haemorrhage was observed in both groups at days 1 and 2, and the difference between groups was not found to be significant. No significant difference was detected in the percentage of apoptotic chondrocytes between groups at any of the time intervals.

Conclusions

Injection of procaine seems safe to use intra-articularly based on this in vivo study on rat knee cartilage. However, further studies investigating both the analgesic and histopathological effects of procaine on damaged articular cartilage and synovium models are needed.

Single-dose local anesthetics exhibit a type-, dose-, and time-dependent chondrotoxic effect on chondrocytes and cartilage: a systematic review of the current literature

PURPOSE

Many studies have shown that local anesthetics may impede chondrocyte metabolism. However, the influence of a single-dose local anesthetics is controversial. The aim of this metaanalysis was to review the literature for studies investigating the cytotoxic effects of single-dose local anesthetics on chondrocytes and cartilage.

METHODS

A comprehensive literature search was performed using established search engines (Medline, Embase) to identify studies, investigating the influence of single-dose local anesthetics on cartilage. The systematic analysis included the influence on histology, cell viability, morphology, and matrix production depending upon dose, exposure time, and type of local anesthetics.

RESULTS

Twelve studies with four different local anesthetics were included in this metaanalysis. Bupivacaine and lidocaine were found to be more chondrotoxic than mepivacaine and ropivacaine. The amount of dead cells increased in a substance-, dose-, and time-dependent process. Osteoarthritic cartilage seems to be more vulnerable compared to intact cartilage. The toxic effects occur first in the superficial cartilage layers and include damage to membrane integrity, mitochondrial DNA, and nuclear changes. There is no study that could show a significant chondrotoxic effect with low concentrations of bupivacaine (0.0625%), ropivacaine (0.1 and 0.2%), and mepivacaine (0.5%).

CONCLUSIONS

The cytotoxicity of local anesthetics on chondrocytes is dependent on dose, time, and type of local anesthetics. Single-dose intra-articular administration of local anesthetics impede chondrocyte metabolism and should be performed only with low concentrations for selected diagnostic purposes and painful joints. The use of lidocaine should be avoided.

LEVEL OF EVIDENCE

II.

Comparison of Cytotoxic Effects of Intra-Articular Use of Tranexamic Acid versus Epinephrine on Rat Cartilage

Background

Adequate visualization is known to be essential to perform arthroscopic procedures effectively and efficiently. We hypothesized that tranexamic acid may be considered as an alternative agent to reduce intra-articular bleeding during arthroscopic procedures, after comparing its potential chondrotoxicity with that of epinephrine.

Material/Methods

Seventy-two rats were randomized into 3 groups with 24 rats each. The injections were performed in the right knees, as follows: Group 1: 0.25 mL of tranexamic acid solution, Group 2: 0.25 mL of epinephrine solution, and Group 3: 0.25 mL of 0.9% saline, serving as control. One week after the injections, the animals were euthanized. Samples were evaluated histologically based on the Osteoarthritis Research Society International (OARSI) Histopathology Grading and Staging System and the “live/dead” staining technique to determine chondrocyte viability.

Results

Comparison of epinephrine and tranexamic acid revealed significantly higher OARSI scores in the epinephrine group (epinephrine: 3.42±1.31, TA: 0.92±0.90; P<0.001). The most significant difference between the 2 groups was in the number of joints diagnosed with OARSI grade III. The percentage of viability was significantly higher in the tranexamic acid group when compared with the epinephrine group (tranexamic acid: 79.74±3.343; epinephrine: 63.81±1.914; P<0.05).

Conclusions

Based on the histologic parameters and chondrocyte viability, tranexamic acid is less cytotoxic than epinephrine in rat chondrocytes at the doses typically used in irrigation fluid, and may be a good alternative to epinephrine in arthroscopic surgery.

An Effective Treatment in the Austere Environment? A Critical Appraisal into the Use of Intra-Articular Local Anesthetic to Facilitate Reduction in Acute Shoulder Dislocation

Acute shoulder dislocation is a common injury in the outdoor environment. The objective of this systematic review of the literature was to determine if intra-articular local anesthetic (IAL) is an effective treatment that could have prehospital application. A methodical search of MEDLINE, PubMed, and EMBASE databases targeted publications from January 1, 1990 until January 1, 2017. Eligible articles compared IAL with other analgesic techniques in patients 16 years or older experiencing acute glenohumeral dislocation. Reduction success, complications, and patient-reported outcome measures underwent comparison. All identified publications originated from the hospital setting. Procedural success rates ranged widely among randomized control trials comparing IAL with intravenous analgesia and sedation (IAL 48-100%, intravenous analgesia and sedation 44-100%). A pooled risk ratio [RR] favored intravenous analgesia and sedation (RR 0.91, 95% confidence interval [CI] 0.84-0.98), but there was significant inconsistency within the analysis (I² = 75%). IAL provided lower complication rates (4/170, 2%) than intravenous analgesia and sedation (20/150, 13%) (RR 1.11, 95% CI 1.04-1.19, I² = 63%). One trial found a clinically relevant reduction in visual analogue pain scores when comparing IAL against no additional analgesia in the first minute (IAL 21±13 mm; control 49±15 mm; P<0.001) and fifth minute (IAL 10±10 mm; control 40±14 mm, P<0.001) after reduction. The results suggest that IAL is an effective intervention for acute anterior shoulder dislocation that would have a place in the repertoire of the remote physician. Further research might be beneficial in determining the outcomes of performing IAL in the prehospital setting.

In Vitro Chondrotoxicity of Nonsteroidal Anti-inflammatory Drugs and Opioid Medications

BACKGROUND

A variety of medications are administered to the intra-articular space for the relief of joint pain. While amide-type local anesthetics have been extensively studied, there is minimal information regarding the potential chondrotoxicity of nonsteroidal anti-inflammatory drugs (NSAIDs) and opioid medications.

PURPOSE

To investigate the in vitro chondrotoxicity of single-dose equivalent concentrations of ketorolac, morphine, meperidine, and fentanyl on human chondrocytes.

STUDY DESIGN

Controlled laboratory study.

METHODS

Human cartilage was arthroscopically harvested from the intercondylar notch and expanded in vitro. Gene expression of cultured chondrocytes before treatment was performed with quantitative polymerase chain reaction for type I collagen, type II collagen, aggrecan, and SOX9. Chondrocytes were then exposed to 0.01%, 0.02%, and 0.04% morphine sulfate; 0.3% and 0.6% ketorolac tromethamine; 0.5%, 1.0%, and 1.5% meperidine hydrochloride; 0.0005% and 0.001% fentanyl citrate; and saline. A custom bioreactor was used to constantly deliver medications, with the dosage of each medication and the duration of exposure based on standard dose equivalents, medication half-lives, and differences in the surface area between the 6-well plates and the native joint surface. After treatment, a live/dead assay was used to assess chondrocyte viability and if minimal cell death was detected. A subset of samples after treatment was maintained to analyze for possible delayed cell death.

RESULTS

All tested concentrations of ketorolac and meperidine caused significantly increased cell death versus the saline control, demonstrating a dose-response relationship. The morphine and fentanyl groups did not show increased chondrotoxicity compared with the saline group, even after 2 weeks of additional culture.

CONCLUSION

In vitro exposure of chondrocytes to single-dose equivalent concentrations of either ketorolac or meperidine demonstrated significant chondrotoxicity, while exposure to morphine or fentanyl did not lead to increased cell death.

Local anaesthetics or their combination with morphine and/or magnesium sulphate are toxic for equine chondrocytes and synoviocytes in vitro

Background

Chondrotoxic effects of local anaesthetics are well reported in humans and some animal species but knowledge on their toxic effects on synoviocytes or equine chondrocytes or the effects on cellular production of inflammatory cytokines is limited. The purpose of this study was to evaluate the in vitro effects of local anaesthetics, morphine, magnesium sulphate (MgSO₄) or their combinations on cell viability and pro-inflammatory cytokine gene expression of equine synoviocytes and chondrocytes.

Equine synoviocytes and cartilage explants harvested from normal joints in a co-culture system were exposed to mepivacaine (4.4 mg/ml), bupivacaine (2.2 mg/ml), morphine (2.85 mg/ml) and MgSO₄ (37 mg/ml) alone or each local anaesthetic plus morphine or MgSO₄ or both together. Chondrocyte and synoviocyte cell viability was assessed by CellTiter-Glo Luminescent Cell Viability Assay. Synoviocyte gene expression of IL-1β, IL-6 or TNF-α was measured and compared using the ∆∆CT method.

Results

Morphine alone, MgSO₄ alone or their combination did not alter cell viability or the expression of IL-1β, IL-6 or TNF-α. However, local anaesthetics alone or in combination with morphine and/or MgSO₄ reduced cell viability and increased the gene expression of IL-1β, IL-6 or TNF-α. Single short exposure to local anaesthetics is toxic to both chondrocytes and synoviocytes and their combination with morphine and/or MgSO₄ enhanced the cytotoxic effects.

Conclusions

This in vitro study gives further evidence of the absence of cytotoxic effects of morphine alone, MgSO₄ alone or their combination on normal articular tissues. However, local anaesthetics alone or in combination with morphine and/or MgSO₄ have cytotoxic effects on equine articular tissues.

Electronic supplementary material

The online version of this article (10.1186/s12917-017-1244-8) contains supplementary material, which is available to authorized users.

Effect of platelet concentration on clinical improvement in treatment of early stage-knee osteoarthritis with platelet-rich plasma concentrations

[Purpose] To compare two platelet-rich plasma kits with different platelet concentrations for treatment of knee osteoarthritis. [Subjects and Methods] Male and female patients with knee osteoarthritis who had confirmed diagnosis with X-ray and magnetic resonance imaging were included in this retrospective study. Eligible patients were divided into two groups: Group I, which received platelet-rich plasma kit I, and Group II, which received platelet-rich plasma kit II. Platelet concentrations of both kits were measured by manual counting. For each group, platelet-rich plasma kit was injected twice with a one-month interval between injections. The Western Ontario and McMaster Universities Osteoarthritis Index and the Visual Analog Scale were applied for clinical evaluation before the first injection and one, three and six months after the second injection. [Results] Kits I and II contained 1,000,000 and 3,000,000 platelets/µl respectively. In both groups, initial Western Ontario and McMaster Universities Osteoarthritis Index and Visual Analog Scale scores were significantly higher compared to the latter evaluations. However, no significant difference was observed between groups in terms of clinical evaluations. [Conclusion] Similar clinical results were found in groups receiving different platelet concentrations, therefore, a concentration of 1,000,000 platelet/µl is considered sufficient for pain relief and functional recovery.

N-acetyl cysteine protects cells from chondrocyte death induced by local anesthetics

Local anesthetics (LA) are among the drugs most frequently used for musculoskeletal problems, in procedures ranging from diagnosis to postoperative pain control. Chondrocyte toxicity induced by LA is an emerging area of concern. The purpose of this study was to determine whether N-acetyl cysteine (NAC), an antioxidant, will exert cytoprotective effects against chondrocyte death induced by LA. Primary cultured human chondrocytes were used for this study. This study used control, NAC, LA, and NAC-LA groups. Cytotoxicity was induced in the LA subgroups and their paired NAC-LA subgroups through exposure to ropivacaine (0.075%), bupivacaine (0.05%), or lidocaine (0.2%) for 24 h. The NAC-LA subgroups were exposed to 10 mM NAC for 1 h, before LA exposure. These study groups were evaluated for rates of cell viability, apoptosis, necrosis, intracellular ROS production, and caspase-3/7 activity. Cell viability in all LA subgroups was significantly lower than in the control group (p < 0.001). Cell viability in the NAC-LA subgroups was significantly higher than in their paired LA subgroups (p < 0.001). In the LA subgroups, rates of apoptosis and necrosis, intracellular ROS production, and caspase-3/7 activity were significantly higher than in the control group (p ≤ 0.029). In the NAC-LA subgroups, rates of apoptosis and necrosis, intracellular ROS production, and caspase-3/7 activity were significantly lower than in their paired LA subgroups (p ≤ 0.023). These results indicate that N-acetyl cysteine, an antioxidant, has cytoprotective effects against LA-induced toxicity to chondrocytes in vitro. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:297-303, 2017.