Chondrotoxicity of low pH, epinephrine, and preservatives found in local anesthetics containing epinephrine

Review of intra-articular local anaesthetic administration in horses: Clinical indications, cytotoxicity, and outcomes

Equine practitioners frequently inject local anaesthetics (LA) intra-articularly in both diagnosis of lameness and for pain management intra- or post-operatively with synovial endoscopy. Recent reviews of the human and veterinary literature support the concept that chondrotoxicity of LA on joint tissues depends on the type of drug, dose administered, and duration of exposure. The purpose of this review is to summarise the current literature describing intra-articular local anaesthetic use, including both in vitro and in vivo studies, and to draw some comparisons to literature from other species where potential toxicity and duration of effect have been evaluated with the goal of advancing the field's understanding of intra-articular local anaesthetic use in horses, and indicating future directions for the field. The aggregate data available from all species, while generally sparse for horses, indicate that LA are rapidly cleared from the synovial fluid after injection, often within 30 min. In vitro data strongly suggest that lidocaine and bupivacaine are likely more chondrotoxic than other LA, although to what extent is still unknown, and cytotoxicity of LA may be mitigated through concurrent injection with HA, PRP, and drug combinations including nonsteroidal anti-inflammatories and opioids. The current body of in vitro research is not reflective of the in vivo environment, and further in vitro work, if performed, should focus on mimicking the native joint environment, utilising PK data and joint/injection volumes to replicate the native environment more accurately within the joint and the expected exposures to LA.

Is Ultrasound-guided or Landmark-guided Intra-articular Lidocaine Injection More Effective for Pain Control in Anterior Shoulder Dislocation Reduction? A Randomized Controlled Trial

BACKGROUND

Effective pain control during reduction of shoulder dislocation is essential for patient comfort. However, there is a lack of comprehensive research comparing the efficacy of different pain management techniques, specifically landmark-guided and ultrasound-guided intra-articular analgesic injections.

QUESTIONS/PURPOSES

Among patients undergoing closed reduction of a shoulder dislocation, were there differences between an intra-articular shoulder injection placed using anatomic landmarks and an ultrasound-guided intra-articular injection in terms of (1) pain before versus after the injection and pain before injection versus after the reduction, or (2) length of stay in the emergency department and complications of the procedure?

METHODS

Between August 2021 and March 2023, 28 patients with anterior shoulder dislocation were treated at the emergency department of a tertiary referral care center. They were randomly assigned to either the landmark-guided or ultrasound-guided intra-articular lidocaine injection group. Differences in pain levels between preinjection and postinjection, preinjection and postreduction, length of hospital stay, and complications were assessed and compared between the two groups. Patients were followed for 2 weeks.

RESULTS

There were no between-group differences in terms of age, gender, baseline pain score, and any other relevant factors. There were no differences between the groups in terms of pain reduction between preinjection and postinjection (landmark-guided: ΔVAS 2.8 ± 1.1, ultrasound-guided: ΔVAS 2.9 ± 1.0, mean difference -0.14 [95% confidence interval -0.97 to 0.68]; p = 0.72) or between preinjection and postreduction (landmark-guided: ΔVAS 6.6 ± 2.1, ultrasound-guided: ΔVAS 5.8 ± 1.8, mean difference 0.79 [95% CI -0.74 to 2.31]; p = 0.30). There were no differences in length of stay in the emergency department (landmark-guided: 162 ± 38 minutes, ultrasound-guided: 184 ± 73 minutes, mean difference 22 minutes [95% CI -67 to 24]; p = 0.33), and no complications were reported in either group during the 2-week follow-up period.

CONCLUSION

The results of the landmark-guided technique were not different from those of ultrasound-guided injection in terms of lower pain levels, length of stay, and complications. These findings provide valuable guidance for orthopaedic surgeons, enabling them to make informed decisions based on their expertise and available resources.

LEVEL OF EVIDENCE

Level I, therapeutic study.

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.

Tourniquet-less arthroscopic anterior cruciate ligament reconstruction: a technical guide & narrative review of the evidence

Arthroscopic anterior cruciate ligament reconstruction (ACLR) is often performed with the use of a thigh tourniquet. Surgeons believe this helps improve visualisation and reduce operative time. However, tourniquet use has been associated with many complications including increased pain, neurovascular injury, venous thromboembolism, haematoma formation, and others. In this article, we describe a method allowing comparable arthroscopic visualisation to be achieved without the aid of a tourniquet for ACLR procedures. The literature evidence relating to this technique as well as tourniquet use for ACLR is also reviewed. Tourniquet-less ACLR can be achieved through the combined application of hypotensive anaesthesia, intravenous tranexamic acid, and use of adrenaline-supplemented irrigation fluid and local anaesthetic. Performing ACLR without a tourniquet avoids the risks associated with its use and reduces the severity of post-operative haemarthrosis which may contribute to the patient's pain and limit their ability to perform their rehabilitation exercises.

Intra-articular administration of adrenaline plus an irrigation pump system for visibility during the arthroscopic reconstruction of multiple knee ligaments without a tourniquet

Objective

Multiple ligament knee injuries (MLKIs) are rare but severe systemic trauma. Single surgery in the acute setting is preferred, although with an extended operation time. To avoid the complications associated with a tourniquet, we herein describe a method for visibility without a tourniquet: intra-articular administration of adrenaline plus an irrigation pump system.

Study design

This is a cohort study with a level of evidence of 3.

Methods

From April 2020 to February 2022, 19 patients with MLKIs were reviewed retrospectively. All patients got intra-articular administration of adrenaline plus an irrigation pump system for visibility without a tourniquet. The following parameters were assessed: visibility, range of motion, knee stability, visual analog scale (VAS) score, range of motion (ROM), Lysholm score, Tegner activity level, and International Knee Documentation Committee Subjective Knee Form (IKDC).

Results

All patients were followed up for at least 6 months. At the latest follow-up, the mean VAS score, ROM, Lysholm score, and IKDC were 1.79 ± 0.86, 121.21 ± 10.96, 88.16 ± 5.21, and 88.53 ± 5.06, respectively. The average Tegner activity level decreased significantly from preinjury to postoperation (5.16 ± 0.83 vs. 3.11 ± 0.88, P < 0.001). Of the 19 patients, 17 (89.47%) had good knee function, while only two patients (10.53%) had asymptomatic knees with positive Lachman tests. A total of 17 patients (89.47%) had good or excellent visualization during arthroscopy. Of the 19 patients, three (15.79%) required an increased fluid pressure to achieve a clear operative view. Two patients converted to tourniquet inflation due to persistent intra-articular bleeding after using shavers.

Conclusions

The intra-articular administration of adrenaline plus an irrigation pump system is recommended as an alternative to a tourniquet to achieve a good visual field. Further evidence-based work with a larger sample is needed.

An Injectable Containing Morphine, Ropivacaine, Epinephrine, and Ketorolac Is Not Cytotoxic to Articular Cartilage Explants From Degenerative Knees

PURPOSE

The purpose of this study was to determine the effects of a multidrug injectate containing morphine, ropivacaine, epinephrine, and ketorolac, commonly referred to as the "Orthococktail," on cartilage tissue viability and metabolic responses using an established in vitro model.

METHODS

With institutional review board approval and informed patient consent, tissues normally discarded after total knee arthroplasty (TKA) were recovered. Full-thickness cartilage explants (n = 72, Outerbridge grade 1 to 3) were created and bisected. Paired explant halves were treated with either 1 mL Orthococktail or 1 mL of saline and cultured for 8 hours at 37°C, with 0.5 mL of the treatment being removed and replaced with tissue culture media every hour. Explants were cultured for 6 days, and media were changed and collected on days 3 and 6. After day 6, tissues were processed for cell viability, weighed, and processed for histologic grading. Outcome measures were compared for significant differences between treated and untreated samples.

RESULTS

There were no significant differences in cartilage viability between control and Orthococktail-treated samples across a spectrum of cartilage pathologies. Orthococktail treatment consistently resulted in a significant decrease in the release of PGE2, MCP-1, MMP-7, and MMP-8 on day 3 of culture and PGE2, MMP-3, MMP-7, and MMP-8 on day 6 of culture, compared with saline controls.

CONCLUSION

The results of the present study indicate that an Orthococktail injection composed of morphine, ropivacaine, epinephrine, and ketorolac is associated with a transient decrease in degradative and inflammatory mediators produced by more severely affected articular cartilage and may mitigate perioperative joint pain such that postoperative narcotic drug use could be reduced.

CLINICAL RELEVANCE

The Orthococktail solution used in this study may be a safe intraoperative, intra-articular injection option for patients undergoing joint arthroplasty and other joint preservation surgical procedures.

Analgesia in Athletes: A Review of Commonly Used Oral and Injectable Modalities

Pain is common among athletes at all levels and the treatment of pain can be a challenging and frustrating task. The team physician needs a fundamental knowledge of analgesic strategies as it relates to athletes. It is important to understand the mechanism of action, side effect profile/associated complications, incidence of and indications for use, as well as the controversies associated with the most common analgesic medications used in sports medicine. Several "in vogue" treatment modalities, including cannabidiol, are also becoming more commonly used and are worth discussion.

Accuracy of Landmark-guided Glenohumeral Joint Injections as Assessed by Ultrasound in Anterior Shoulder Dislocations

Introduction

To determine the accuracy of landmark-guided shoulder joint injections (LGI) with point-of-care ultrasound for patients with anterior shoulder dislocations.

Methods

Patients with anterior shoulder dislocations who underwent LGI were enrolled at our tertiary-care and trauma center. LGI attempts were recorded by an ultrasound fellowship-trained ED physician who determined if they were placed successfully. Pain and satisfaction scores were recorded.

Results

A total of 34 patients with anterior shoulder dislocation and their treating ED physicians were enrolled. 41.1% of all LGI were determined to be misplaced (n=14). Patients with successful LGI had a greater decrease in mean pain scores post-LGI.

Conclusions

LGI had a substantial failure rate in our study. Using ultrasound-guidance to assist intra-articular injections may increase its accuracy and thus reduce pain and the need for subsequent procedural sedation.

Evaluation of the in vitro effects of local anesthetics on equine chondrocytes and fibroblast-like synoviocytes

OBJECTIVE

To investigate the in vitro effects of clinically relevant concentrations of the local anesthetics (LAs) bupivacaine, lidocaine, lidocaine with preservative (LP), mepivacaine, and ropivacaine on equine chondrocyte and fibroblast-like synoviocyte (FLS) viability.

SAMPLES

Chondrocytes and FLSs of the metacarpophalangeal joints of 4 healthy adult horses.

PROCEDURES

Viability of chondrocytes and FLSs was determined with 3 assays: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), lactate dehydrogenase (LDH), and trypan blue (TB) exclusion (only FLS). Viability was assessed after 30- and 60-minute exposures to 0.0625%, 0.125%, and 0.25% bupivacaine; 0.25%, 0.5%, and 1% lidocaine; 0.25%, 0.5%, and 1% LP; 0.25%, 0.5%, and 1% mepivacaine; and 0.125%, 0.25%, and 0.5% ropivacaine.

RESULTS

Viability of chondrocytes was significantly decreased with exposure to 0.25% bupivacaine, 1% lidocaine, 1% LP, 1% mepivacaine, and 0.25% ropivacaine. Viability of FLSs was significantly decreased with exposure to 0.25% bupivacaine, 1% mepivacaine, 1% LP, and 0.5% ropivacaine.

CONCLUSIONS AND CLINICAL RELEVANCE

Clinically relevant concentrations of LAs had in vitro time- and concentration-dependent cytotoxicity for chondrocytes and FLSs isolated from the metacarpophalangeal joints of healthy horses. Bupivacaine was more toxic to chondrocytes than lidocaine, mepivacaine, and ropivacaine, whereas bupivacaine, LP, mepivacaine, and ropivacaine were more toxic to FLSs than preservative-free lidocaine. Several LAs may negatively affect chondrocyte and FLS viability.

Avaliação da adição da epinefrina à bupivacaína intra-articular no controle da dor aguda em pacientes submetidos a reconstrução do ligamento cruzado anterior

Objective  To evaluate postoperative pain, using the visual analog scale (VAS), in patients undergoing anterior cruciate ligament reconstruction (ACLR) and receiving intra-articular anesthetic solutions.

Methods  The present is a randomized clinical trial with a sample of 48 patients divided into 4 groups: Group I (n = 12) – 20 mL of saline solution (control); Group II (n = 12) – 20 mL of 0.5% bupivacaine; Group III (n = 12) – 20 mL of 0.5% bupivacaine + 0.1 mg of epinephrine; and Group IV (n = 12) – 20 mL of saline solution + 0.1 mg of epinephrine. These solutions were injected into the knee at the end of the surgery. Pain was assessed using the VAS immediately and 6, 12, 24 and 48 hours after the procedure.

Results  The VAS scores were highly variable among the groups. A Kruskal-Wallis analysis of variance (ANOVA), considering a level of significance of 5%, revealed that all intra-articular anesthetic solutions influenced the assessment of pain ( p  = 0.003), and that Group-III subjects presented less postoperative pain. There was no evidence of a higher or lower use of supplemental analgesic agents, or of adverse effects resulting from these anesthetic solutions.

Conclusion  Bupivacaine combined with epinephrine was the most effective solution for pain control in patients undergoing ACLR, but with no statistically significant differences when compared to Group II ( p  = 0.547). There was no decrease or increase in the use of supplemental analgesics or in the occurrence of adverse systemic effects ( p  > 0.05).

Visualization in arthroscopic meniscectomy- portal-site injection versus tourniquet inflation: A prospective, double-blinded, randomised controlled study

Objectives

Alternatives to tourniquets include portal-site epinephrine injections. This prospective, randomised-controlled, double-blinded study compared intraoperative visibility and safety of portal-site injections with tourniquets in arthroscopic meniscectomies.

Methods

Sixty eligible adults [16-55ys, excluding vascular/neuromuscular/systemic illnesses] were randomly/equally divided across 3 groups A (controls)-local portal injections; B-local injections with tourniquet; C-local and 1:200,000epinephrine injections. A single surgeon operated blinded to patient group. Intraoperative visibility, surgeon visual analogue score (VAS)and other details were recorded.

Results

Superior visibility [p = 0.003,p = 0.027] and VAS [p = 0.010,p = 0.042] were reported in groups B, C versus A, Visibility [p = 0.705; p = 0.805] and operating times [p = 0.05] were comparable between B and C.

Conclusions

Portal-site epinephrine injections emerged as tenable surrogates for tourniquets for clear visualization in arthroscopy.

Effects of intra-articular administration of lidocaine, mepivacaine, and the preservative methyl parahydroxybenzoate on synovial fluid biomarkers of horses

OBJECTIVE

To compare the extent of inflammation and catabolic collagen response in the middle carpal joints (MCJs) of healthy horses following intra-articular injection of 2% lidocaine, 2% mepivacaine, lactated Ringer solution (LRS), or 0.1% methyl parahydroxybenzoate.

ANIMALS

17 adult horses.

PROCEDURES

In the first of 2 experiments, the left middle carpal joint (MCJ) of each of 12 horses was injected with 10 mL of 2% lidocaine (n = 3), 2% mepivacaine (3), or LRS (control; 6). After a 4-week washout period, the right MCJ of the horses that received lidocaine or mepivacaine was injected with 10 mL of LRS, and the right MCJ of horses that received LRS was injected with 10 mL of 2% lidocaine (n = 3) or 2% mepivacaine (3). In experiment 2, the left MCJ of each of 5 horses was injected with 10 mL of 0.1% methyl parahydroxybenzoate. After a 48-hour washout period, the right MCJ of each horse was injected with 10 mL of LRS. Synovial fluid (SF) samples were aseptically collected before and at predetermined times after each injection. Synovial fluid WBC count, neutrophil percentage, and total protein, neutrophil myeloperoxidase, neutrophil elastase, and Coll2-1 concentrations were compared among treatments.

RESULTS

Both lidocaine and mepivacaine induced SF changes indicative of inflammation and a catabolic collagen response, but the magnitude of those changes was more pronounced for lidocaine. Methyl parahydroxybenzoate did not cause any SF changes indicative of inflammation.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that mepivacaine was safer than lidocaine for intra-articular injection in horses.

Nonbiologic Injections in Sports Medicine

Nonbiologic medications (local anesthetics, corticosteroids, and nonsteroidal anti-inflammatory drugs) are commonly administered to athletes for analgesia after injury. However, the risks of nonbiologic injections often are overlooked simply because of their long-term market availability. A thorough understanding of the mechanism of action, the reported benefits, and the potential risks of nonbiologic medications is crucial prior to their use, especially in the treatment of young athletes. Sports medicine physicians and surgeons must be aware of the systemic and local effects of these medications to ensure an appropriate drug choice that minimizes side effects and avoids recently reported toxicity to myocytes, tenocytes, and chondrocytes.

Viability of Equine Chondrocytes After Exposure to Mepivacaine and Ropivacaine In Vitro

Chondrocyte health is altered when exposed to local anesthetics, raising concerns as to the long-term effects of local anesthetics intra-articularly for diagnosis and analgesia. To investigate the drug with the lowest toxic potential, the effect of ropivacaine and mepivacaine on chondrocytes was evaluated. Articular cartilage from normal metacarpophalangeal joints of five equine cadaver specimens was used to establish chondrocyte cultures. Following seven days, chondrocytes were exposed to standard culture medium (DMEM), ropivacaine 7.5 mg/ml (ROP7.5), ropivacaine 10 mg/ml (ROP10), mepivacaine 20 mg/ml (MEP20), mepivacaine 30 mg/ml (MEP 30), and 0.9% saline solution (SAL). Chondrocyte viability was evaluated by trypan blue exclusion, MTT, and flow cytometry via cellular staining with propidium iodide. No differences were observed between treatments following trypan blue exclusion assay. A difference was observed between DMEM and all other treatment groups (P < .0001) with a significant viability drop using the MTT assay. Mepivacaine 20 mg/ml and MEP30 exposure between showed greatest decrease in cellular viability compared to SAL, ROP7.5, and ROP10 (P < .0001). Cellular viability decreased as measured by flow cytometry in all groups compared to DMEM and ROP7.5 (P < .02). Interestingly, the trypan blue, MTT, and flow cytometry assays yielded different results. Although there was no difference using trypan blue, MTT demonstrated that ropivacaine-treated cells had lower viability than DMEM, and cytometry found that ROP7.5 did not differ from DMEM. Results in vitro suggest that short-term exposure to ropivacaine may result in less chondrotoxicity than mepivacaine. In vivo studies are warranted investigating long-term effects of local anesthetics on equine articular cartilage.

Effect of naproxen on proliferation and differentiation of primary cell cultures isolated from human cartilage tissue

Non-steroidal anti-inflammatory drugs (NSAIDs) that are applied through oral, injectable or topical routes have been widely used in painful and inflammatory musculoskeletal diseases. The current study aimed to determine whether naproxen, an aryl acetic acid derivative with analgesic and anti-inflammatory effects, has a toxic effect on human chondrocytes. Samples containing monolayer primary chondrocyte cultures were prepared following resection from osteochondral tissues obtained from patients with gonarthrosis. Cell viability, toxicity and proliferation and levels of stage-specific embryonic antigen-1, a precursor to human prechondrocytes, were evaluated spectrophotometrically. The results from the untreated control group were compared with those of the study groups, where naproxen was administered in varying doses (1-1,000 µM). Surface morphologies of the cells were compared using inverted light and environmental scanning electron microscopy. Treatment groups were compared by analysis of variance with Tukey's honest difference post hoc test. P<0.01 was considered to indicate a statistically significant difference. The research revealed significant changes to proliferation and differentiation of chondrocytes in all treatment groups (P<0.01). Naproxen was demonstrated to suppress chondrocyte proliferation and differentiation, which may be an important factor to consider when prescribing this medication to patients.

Effect of local infiltration analgesia, peripheral nerve blocks, general and spinal anesthesia on early functional recovery and pain control in unicompartmental knee arthroplasty

Background

The aim of the study was to analyze the effect of local infiltration analgesia (LIA), peripheral nerve blocks, general and spinal anesthesia on early functional recovery and pain control in primary unicompartmental knee arthroplasty (UKA).

Methods

Between January 2016 until August 2016, 134 patients underwent primary UKA and were subdivided into four groups according to their concomitant pain and anesthetic procedure with catheter-based techniques of femoral and sciatic nerve block (group GA&FNB, n = 38) or epidural catheter (group SP&EPI, n = 20) in combination with general anesthesia or spinal anesthesia, respectively, and LIA combined with general anesthesia (group GA&LIA, n = 46) or spinal anesthesia (group SP&LIA, n = 30). Outcome parameters focused on the evaluation of pain (NRS scores), mobilization, muscle strength and range of motion up to 7 days postoperatively. The cumulative consumption of (rescue) pain medication was analyzed.

Results

The LIA groups revealed significantly lower (about 50%) mean NRS scores (at rest) compared to the catheter-based groups at the day of surgery. In the early postoperative period, the dose of hydromorphone as rescue pain medication was significantly lower (up to 68%) in patients with SP&EPI compared to all other groups. No significant differences could be detected with regard to grade of mobilization, muscle strength and range of motion. However, there seemed to be a trend towards improved mobilization and muscle strength with general anesthesia and LIA, whereof general anesthesia generally tended to ameliorate mobilization.

Conclusions

Except for a significant lower NRS score at rest in the LIA groups at day of surgery, pain relief was comparable in all groups without clinically relevant differences, while the use of opioids was significantly lower in patients with SP&EPI. A clear clinically relevant benefit for LIA in UKA cannot be stated. However, LIA offers a safe and effective treatment option comparable to the well-established conventional procedures.

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.

Improved Chondrotoxic Profile of Liposomal Bupivacaine Compared With Standard Bupivacaine After Intra-articular Infiltration in a Porcine Model

BACKGROUND

Increasingly, liposomal bupivacaine is being used with multimodal pain management strategies. In vitro investigations have shown decreased chondrotoxicity profiles for liposomal bupivacaine; however, there is no evidence regarding its in vivo effects. Hypothesis/Purpose: This study sought to investigate the in vivo chondrotoxicity of liposomal bupivacaine, hypothesizing that there would be increased chondrocyte viability after exposure to liposomal bupivacaine when compared with standard bupivacaine.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eight juvenile, female Yorkshire cross piglets underwent a lateral stifle joint injection with either 1.3% liposomal bupivacaine or 0.5% bupivacaine. Injections were performed on one joint per animal with no injection to the contralateral knee, which served as the control. Chondrocyte viability was assessed 1 week after injection with a live-dead staining protocol and histologic examination.

RESULTS

Significant chondrocyte death was seen with the live-dead staining in the bupivacaine group (33% nonviable cells) in comparison with liposomal bupivacaine (6.2%) and control (5.8%) groups ( P < .01). However, histologic examination showed no differences in chondral surface integrity, fibrillation, and chondrocyte viability.

CONCLUSION

Liposomal bupivacaine was found to be safe for intra-articular injection in this animal model. Although bupivacaine demonstrated decreased chondrocyte viability on a cellular level, histologically there were no changes. This study highlights the dichotomy between fluorescent staining and histologic appearance of articular chondrocytes in short-term analyses of viability.

CLINICAL RELEVANCE

This study supports the peri-articular application of liposomal bupivacaine in the setting of preserved articular cartilage. A single injection of standard bupivacaine did not produce histologic changes in the articular cartilage.

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.

Glucosamine reduces the inhibition of proteoglycan metabolism caused by local anaesthetic solution in human articular cartilage: an in vitro study

Background

We assessed whether local anaesthetics caused inhibition of proteoglycan metabolism in human articular cartilage and whether the addition of Glucosamine sulphate could prevent or allow recovery from this adverse effect on articular cartilage metabolism.

Methods

Cartilage explants obtained from 13 femoral heads from fracture neck of femur patients (average age 80 years, 10 female) were exposed to either 1% Lidocaine, 2% Lidocaine, 0.25% Bupivacaine, 0.5% Bupivacaine, 0.5% Levo-bupivacaine or a control solution (M199 culture medium). Glucosamine-6-Sulphate was added during or 1 h after exposure to 0.5% Bupivacaine to assess its protective and reparative effects. After exposure, the explants were incubated in culture medium containing radio labelled 35-sulphate and uptake was measured after 16 h to give an assessment of proteoglycan metabolism.

Results

The reduction in 35-S uptake compared to control was 65% for 1% Lidocaine (p < 0.001), 79% for 2% Lidocaine (p < 0.001), 61% for 0.25% Bupivacaine (p < 0.001), 85% for 0.5% Bupivacaine (p < 0.001) and 77% for 0.5% Levobupivacaine (p < 0.001). Glucosamine was able to protect the articular cartilage by reducing the inhibition of proteoglycan metabolism of 0.5% Bupivacaine from 85 to 30% (p < 0.001). When added after 0.5% Bupivacaine exposure, Glucosamine allowed some recovery with inhibition of metabolism to 70% (p = 0.004).

Conclusion

Our results showed that all local anaesthetic solutions inhibited proteoglycan metabolism in articular cartilage and the addition of Glucosamine was able to reduce the inhibition of metabolism caused by 0.5% Bupivacaine. Intra-articular injection of local anaesthetics requires careful consideration of risks and benefits.

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.

Epinephrine Diluted Saline-Irrigation Fluid in Arthroscopic Shoulder Surgery: A Significant Improvement of Clarity of Visual Field and Shortening of Total Operation Time. A Randomized Controlled Trial

PURPOSE

To determine the influence of epinephrine saline irrigation in therapeutic shoulder arthroscopy procedures on the clarity of arthroscopic view. Three subgroups were analyzed; (1) Bankart/SLAP repairs; (2) rotator cuff repairs; and (3) subacromial procedures without rotator cuff repair. Secondary objectives were to evaluate the influence on total operating time and potential cardiovascular adverse reactions.

METHODS

The design of the study was a prospective, randomized, double-blind controlled trial. A total of 101 patients were included. Pressure pump-controlled regular saline irrigation fluid was used in the control group. In the epinephrine group, epinephrine (0.33 mg/L) was added to the saline-irrigation fluid. Visual clarity was rated by a Numeric Rating Scale. Total operation time, total use of irrigation fluid, increases in pump pressure, heart rate, blood pressure, and electrocautery use were registered.

RESULTS

Visual clarity (P = .002) was significantly better and total operating time (P = .008) significantly shorter in the epinephrine group. Total irrigation fluid used was significantly lower in the epinephrine group (P = .001). The greatest effect on visual clarity and shortening of operation time up to 15 minutes was seen in Bankart and SLAP repairs. No significant effect of the addition of epinephrine on heart rate and blood pressure was observed.

CONCLUSIONS

The addition of epinephrine (0.33 mg/L) to irrigation fluid significantly improves visual clarity in most common types of therapeutic shoulder arthroscopy. A significant reduction in total operating time and use of irrigation fluid was observed. The greatest effect on visual clarity and shortening of operation time was seen in Bankart and SLAP group. Therefore, one of our initial hypotheses that the greatest effect would be observed in subacromial and rotator cuff repair procedures was not supported by the data presented. No cardiovascular adverse reactions were seen.

LEVEL OF EVIDENCE

Level 1, Randomized controlled trial.

Comparative effects of vitamin C on the effects of local anesthetics ropivacaine, bupivacaine, and lidocaine on human chondrocytes

BACKGROUND

Intra-articular injections of local anesthetics are commonly used to enhance post-operative analgesia following orthopedic surgery as arthroscopic surgeries. Nevertheless, recent reports of severe complications due to the use of intra-articular local anesthetic have raised concerns.

OBJECTIVES

The study aims to assess use of vitamin C in reducing adverse effects of the most commonly employed anesthetics - ropivacaine, bupivacaine and lidocaine - on human chondrocytes.

METHODS

The chondrocyte viability following exposure to 0.5% bupivacaine or 0.75% ropivacaine or 1.0% lidocaine and/or vitamin C at doses 125, 250 and 500 μM was determined by LIVE/DEAD assay and annexin V staining. Expression levels of caspases 3 and 9 were assessed using antibodies by Western blotting. Flow cytometry was performed to analyze the generation of reactive oxygen species.

RESULTS

On exposure to the local anesthetics, chondrotoxicity was found in the order ropivacaine<bupivacaine<lidocaine. Vitamin C effectively improved the reduced chondrocyte viability and decreased the raised apoptosis levels following exposure to anesthesia. At higher doses, vitamin C was found efficient in reducing the generation of reactive oxygen species and as well down-regulate the expressions of caspases 3 and 9.

CONCLUSIONS

Vitamin C was observed to effectively protect chondrocytes against the toxic insult of local anesthetics ropivacaine, bupivacaine and lidocaine.

Articular cartilage and local anaesthetic: A systematic review of the current literature

BACKGROUND

Chondrolysis involves the breakdown of cartilage following arthroscopic surgery, most commonly affecting the glenohumeral joint.

METHODS

This review summarises all clinical and laboratory studies regarding local anaesthetic (LA) and its association with chondrolysis. We identified 289 papers, 41 of which met our inclusion criteria and were included in the final review.

RESULTS

Bupivacaine, lidocaine, ropivacaine and levobupivacaine are all toxic to cartilage. Intra-articular infusions confer a greater toxicity to cartilage than single injections.

CONCLUSIONS

Intra-articular LA pain pumps carry a high risk of chondrolysis and should be avoided. Further studies are indicated to assess long-term single exposure LA implications.

A Single-Dose Intra-Articular Morphine plus Bupivacaine versus Morphine Alone following Knee Arthroscopy: A Systematic Review and Meta-Analysis

Objectives

The purpose of this study was to compare the efficacy and safety of a single-dose intra-articular morphine plus bupivacaine versus morphine alone in patients undergoing arthroscopic knee surgery.

Methods

Randomized controlled trials comparing a combination of morphine and bupivacaine with morphine alone injected intra-articularly in the management of pain after knee arthrocopic surgery were retrieved (up to August 10, 2014) from MEDLINE, the Cochrane Library and Embase databases. The weighted mean difference (WMD), relative risk (RR) and their corresponding 95% confidence intervals (CIs) were calculated using RevMan statistical software.

Results

Thirteen randomized controlled trials were included. Statistically significant differences were observed with regard to the VAS values during the immediate period (0-2h) (WMD -1.16; 95% CI -2.01 to -0.31; p = 0.007) and the time to first request for rescue analgesia (WMD = 2.05; 95% CI 0.19 to 3.92; p = 0.03). However, there was no significant difference in the VAS pain score during the early period (2-6h) (WMD -0.36; 95% CI -1.13 to 0.41; p = 0.35), the late period (6-48h) (WMD 0.11; 95% CI -0.40 to 0.63; p = 0.67), and the number of patients requiring supplementary analgesia (RR = 0.78; 95% CI 0.57 to 1.05; p = 0.10). In addition, systematic review showed that intra-articular morphine plus bupivacaine would not increase the incidence of adverse effects compared with morphine alone.

Conclusion

The present study suggested that the administration of single-dose intra-articular morphine plus bupivacaine provided better pain relief during the immediate period (0-2h), and lengthened the time interval before the first request for analgesic rescue without increasing the short-term side effects when compared with morphine alone.

Level of Evidence

Level I, meta-analysis of Level I studies.

Opioids as an alternative to amide-type local anaesthetics for intra-articular application

PURPOSE

Recently, the safety profile of local anaesthetics in intra-articular use became into focus of investigation. Opioid drugs have a different mode of action and may be a safe and potent alternative for intra-articular application. The purpose of this in vitro study is to provide evidence for significant chondrotoxicity of amide-type local anaesthetics even after short-term application on human chondrocytes and to demonstrate the absence of such negative effects for opioids [morphine, morphine-6-glucuronide (M6G)].

METHOD

Visually intact cartilage explants of human, mainly osteoarthritic joints (n = 9), were harvested and cultivated in monolayer for expansion and transferred into alginate bead. The beads were incubated for increasing incubation times (15 min, 1 and 4 h) in decreasing concentrations (full, ½, ¼ for 15 min) of bupivacaine, ropivacaine, morphine, M6G or saline control. Adenosine triphosphate content of 798 beads was measured 3 days post-incubation to assess cell viability.

RESULTS

A clear ranking of cytotoxic potency: bupivacaine > ropivacaine > morphine = M6G = saline was observed. Results reveal a dose- and time-dependent manner of cytotoxic effects on human chondrocytes for bupivacaine and ropivacaine but not for opioids. Cell viability after exposure to morphine and M6G was comparable to exposure to saline.

CONCLUSION

The results confirm dose- and time-dependent cytotoxic effects on human chondrocytes for amide-type local anaesthetics. This study confirms the safety of morphine and M6G in terms of an absence of cytotoxic effects after intra-articular application, making them safe potential alternatives in clinical practice.

Are biological agents toxic to human chondrocytes and osteocytes?

Purpose

The aim of the present study is to investigate the effects of biological agents (BAs) on human chondrocytes and osteocytes in vitro.

Methods

Primary cell cultures obtained from gonarthrosis patients were divided into four groups, two of which were designated as control cultures of chondrocyte and osteocyte, and the other two groups were exposed to BAs administered via the culture medium. Cultured cells were characterized by immunophenotyping. Before and after administration of the agents, the cultures were observed by inverted and environmental scanning electron microscopy (ESEM). The number of live cells and the proliferation rate were monitored by MTT assay.

Results

Rituximab and adalimumab were the least toxic agents to chondrocytes, whereas adalimumab and etanercept were to osteocytes.

Conclusion

During periods of intense active inflammation, the concentration of the preferred BAs after inhibition of inflammation needs to be emphasized when their effects on cartilage and bone tissue are considered at the cellular level if the clinical practice is to continue.

Single-dose intra-articular bupivacaine plus morphine after knee arthroscopic surgery: a meta-analysis of randomised placebo-controlled studies

OBJECTIVES

To evaluate the efficacy and safety of single-dose intra-articular bupivacaine plus morphine after knee arthroscopic surgery.

DESIGN

Meta-analysis.

DATA SOURCES AND STUDY ELIGIBILITY CRITERIA

A comprehensive literature search, using Medline (1966-2014), the Cochrane Central Register of Controlled Trials and Embase databases, was conducted to identify randomised placebo-controlled trials that used a combination of single-dose intra-articular bupivacaine and morphine for postoperative pain relief.

RESULTS

12 articles were included in this meta-analysis. The mean visual analogue scale (VAS) scores of the bupivacaine plus morphine group were significantly lower than those of the placebo group (weighted mean difference (WMD) -1.75; 95% CI -2.16 to -1.33; p<0.001). The VAS scores at the last follow-up time point (last VAS scores) of the bupivacaine plus morphine group were also significantly lower than those of the placebo group (WMD -1.46; 95% CI -1.63 to -1.29; p<0.001). The number of patients requiring supplementary analgesia was also significantly reduced (RR 0.60; 95% CI 0.39 to 0.93; p=0.02), while there was no significant difference in the time to first analgesic request (WMD 3.46; 95% CI -1.81 to 8.72; p=0.20) or short-term side effects (RR 1.67; 95% CI 0.65 to 4.26; p=0.29).

CONCLUSIONS

The administration of single-dose intra-articular bupivacaine plus morphine after knee arthroscopic surgery is effective for pain relief, and its short-term side effects remain similar to saline placebo.

In Vivo Toxicity of Local Anesthetics and Corticosteroids on Chondrocyte and Synoviocyte Viability and Metabolism

OBJECTIVE

Intra-articular injection of local anesthetic and/or corticosteroid is an adjunct treatment for arthritic and inflammatory orthopedic conditions. Despite potential benefits, there is growing concern that these medications may cause significant morbidity, including potential toxicity to intra-articular chondrocytes and synoviocytes.

DESIGN

Twenty dogs underwent intra-articular injection of the shoulder joint using ultrasound guidance, with the following injectates (n = 5 each): negative control (saline), methylprednisolone/1.0% lidocaine, triamcinolone/1.0% lidocaine, and triamcinolone/0.0625% bupivacaine. The dogs were euthanized 24 hours postinjection for reasons unrelated to this study. Synovium/cartilage explants were harvested under sterile conditions and assessed immediately or cultured for 7 days. Synoviocyte and chondrocyte viability was determined on day 1 and day 7 using Calcien AM and Sytox Blue live/dead fluorescent stains, and cell metabolism determined on day 2 using the alamar blue additive test. Results were compared statistically.

RESULTS

On day 1 synovium exposed to 1%L/M demonstrated a significant decrease in cell metabolism (P = 0.0107) and subjective synoviocyte viability scores (P = 0.013) compared with the negative control. Cartilage exposed to 1%L/M demonstrated decreased chondrocyte viability and cell metabolism versus all other groups, although not significantly. After 7 days of culture, cartilage viable cell density in the 1%L/M group was significantly (P ≤ 0.001) lower than the negative control. Subjective synoviocyte viability scores was significantly lower in the 1%L/M (P = 0.013), 1%L/T (P ≤ 0.001), and 0.0625%B/T groups (P = 0.006) compared with the negative control.

CONCLUSIONS

This study suggests potential negative effects of combination local anesthetic/corticosteroid on intra-articular cell viability and cell metabolism. Further study is needed before determining definitive clinical recommendations.

Single-dose intra-articular bupivacaine after knee arthroscopic surgery: a meta-analysis of randomized placebo-controlled studies

PURPOSE

The purpose of this meta-analysis was to examine the efficacy and safety of single-dose intra-articular bupivacaine in the management of pain after knee arthroscopic surgery.

METHOD

The comprehensive literature search, using MEDLINE, the Cochrane Central Register of Controlled Trials, and Embase databases, was conducted to identify randomized controlled trials that used single-dose intra-articular bupivacaine for postoperative pain. The relative risk (RR), weighted mean difference (WMD), and their corresponding 95 % confidence intervals (CIs) were calculated using RevMan(®) statistical software.

RESULT

Twenty-three studies (n = 1287) were included (647 subjects in bupivacaine group and 640 subjects in the control group). Statistically significant differences were observed in the VAS values (WMD -1.1; 95 % CI -1.7 to -0.5), number of patients requiring supplementary analgesia (RR 0.83; 95 % CI 0.74-0.94), and time to first analgesic request (WMD 129.3; 95 % CI 15.4-243.1) among the bupivacaine group when compared to the control group. However, short-term side effects had no significant difference between these two groups (RR 0.73; 95 % CI 0.44-1.24).

CONCLUSIONS

On the basis of the currently available literature, single-dose intra-articular bupivacaine was shown to be significantly better than placebo at relieving pain after knee arthroscopic surgery. More high-quality randomized controlled trials with long follow-up are highly required for examining the safety of single-dose intra-articular bupivacaine. Besides, routine use of single-dose intra-articular bupivacaine is still an effective way for pain management after knee arthroscopic surgery.

Effect of intra-articular local anesthesia on articular cartilage in the knee

PURPOSE

To evaluate the hypothetical toxic effect of local anesthetics on the articular cartilage using patient data from autologous chondrocyte cultivation with different anesthesia types used for arthroscopic cartilage biopsy specimen procurement.

METHODS

A retrospective analysis of patient data from the national autologous chondrocyte implantation registry and the corresponding hospital records was approved by the National Medical Ethics Committee. Articular cartilage biopsy specimens from the knees of 49 consecutive patients assigned for autologous chondrocyte implantation (aged 14 to 44 years) were procured from the non-weight-bearing articular surface during arthroscopy under general anesthesia (12 patients), spinal anesthesia (18 patients), or local anesthesia (intra-articular injection of 15 to 20 mL of 2% lidocaine hydrochloride) (19 patients). All the biopsy specimens were further manipulated following the same chondrocyte cultivation protocol. General patient data and surgery-related parameters, together with chondrocyte viability, population doublings, and chondrocyte morphology in biopsy specimens and primary cell cultures, were analyzed and compared across different types of anesthesia.

RESULTS

Patients in the general, spinal, and local anesthesia groups showed no statistical differences in age (27 years, 29 years, and 32 years, respectively), duration of surgery (36 minutes, 37 minutes, and 39 minutes, respectively), weight of biopsy specimens (110 mg, 178 mg, and 130 mg, respectively), cell viability in cartilage biopsy specimens (67%, 69%, and 78%, respectively) or primary cultures (95%, 95%, and 95%, respectively), and population doublings (5.2, 5.2, and 5.2, respectively). Similar chondrocyte morphology in primary cell cultures was observed among the 3 groups.

CONCLUSIONS

This retrospective study showed that a single intra-articular injection of lidocaine hydrochloride used for knee arthroscopy did not influence the viability, morphology, and cultivation potential of chondrocytes in articular cartilage biopsy specimens assigned for autologous chondrocyte implantation.

LEVEL OF EVIDENCE

Level IV, retrospective comparative study.

Inhibition of chondrocyte and synovial cell death after exposure to commonly used anesthetics: chondrocyte apoptosis after anesthetics

BACKGROUND

An intra-articular injection of local anesthetics is a common procedure for diagnostic and therapeutic purposes. It has been shown that these agents are toxic to articular cartilage and synovial tissue in a dose- and time-dependent fashion, and in some cases, they may lead to postarthroscopic glenohumeral chondrolysis (PAGCL). However, the role of apoptosis in cell death is still unclear, and the potential role of apoptosis inhibition in minimizing chondrocyte and synovial cell death has not been reported.

PURPOSE

(1) To quantify the degree of apoptotic cell death in chondrocytes and synovial cells exposed to local anesthetics, and (2) to determine whether caspase inhibition could reduce cell death.

STUDY DESIGN

Controlled laboratory study.

METHODS

Human chondrocytes and synovial cells were expanded in vitro and exposed to normal saline, 0.5% bupivacaine, 0.5% ropivacaine, 1% lidocaine, or 1:1000 epinephrine for 90 minutes. Apoptosis was then detected at 1, 3, 5, and 7 days after exposure using terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) and immunohistochemistry. Apoptosis was then inhibited using the pan-caspase inhibitor z-vad-fmk. Results were normalized to normal saline controls and analyzed by generalized regression models and pairwise confidence intervals.

RESULTS

Analysis of cumulative chondrocyte apoptosis relative to controls after anesthetic exposure demonstrated more than 60% cell death with 0.5% bupivacaine and 1:1000 epinephrine. The greatest chondroprotective effect of caspase inhibition occurred with 0.5% ropivacaine. Similarly, in synovial cells, epinephrine was also very cytotoxic; however, 1% lidocaine induced the most apoptosis. Synovial cells exposed to 0.5% ropivacaine were again most sensitive to protective caspase inhibition.

CONCLUSION

Local anesthetics induce chondrocyte and synovial cell apoptosis in a time-dependent fashion, with peak apoptosis occurring 5 days after exposure. Both chondrocytes and synovial cells are most sensitive to caspase inhibition after exposure to 0.5% ropivacaine.

CLINICAL RELEVANCE

Apoptosis inhibition may be an effective strategy in minimizing chondrocyte and synovial cell death after exposure to anesthetics. Further investigation is clinically warranted.

Co-administration of hyaluronic acid with local anaesthetics shows lower cytotoxicity than local anaesthetic treatment alone in bovine articular chondrocytes

OBJECTIVE

To study the effect of hyaluronic acid (HA) on local anaesthetic chondrotoxicity in vitro.

METHODS

Chondrocytes were harvested from bovine femoral condyle cartilage and isolated using collagenase-containing media. At 24 hours after seeding 15 000 cells per well onto a 96-well plate, chondrocytes were treated with media (DMEM/F12 + ITS), PBS, 1:1 lidocaine (2%):PBS, 1:1 bupivacaine (0.5%):PBS, 1:1 lidocaine (2%):HA, 1:1 bupivacaine (0. 5%):HA, or 1:1 HA:PBS for one hour. Following treatment, groups had conditions removed and 24-hour incubation. Cell viability was assessed using PrestoBlue and confirmed visually using fluorescence microscopy.

RESULTS

Media-treated groups had a mean of 1.55×10(4) cells/well (sem 783). All treated cells showed statistically significant reduced viability when compared with media alone (all p < 0.003). Cells treated with bupivacaine + HA (6.70×10(3) cells/well (sem 1.10×10(3))) survived significantly more than bupivacaine (2.44×10(3) cells/well (sem 830)) (p < 0.001). Lidocaine + HA (1.45×10(3) cells/well (sem 596)) was not significantly more cytotoxic than lidocaine (2.24×10(3) cells/well (sem 341)) (p = 0.999). There was no statistical difference between the chondrotoxicities of PBS (8.49×10(3) cells/well (sem 730) cells/well) and HA (4.75×10(3) cells/well (sem 886)) (p = 0.294).

CONCLUSIONS

HA co-administration reduced anaesthetic cytotoxicity with bupivacaine but not lidocaine, suggesting different mechanisms of injury between the two. Co-administered intra-articular injections of HA with bupivacaine, but not lidocaine, may protect articular chondrocytes from local anaesthetic-associated death. Cite this article: Bone Joint Res 2013;2:270-5.

Influence of intradiscal medication on nucleus pulposus cells

BACKGROUND CONTEXT

Eugene Carragee was the first to prove that provocative discography may contribute to intervertebral disc degeneration. Disc degeneration can be induced either by mechanical trauma caused by the puncturing needle or as a pharmacological effect of the drugs instilled into the disc.

PURPOSE

The aim of this study was to test the influence of cortisone, lidocaine, and iopamidol on nucleus pulposus cells under an in vitro setting.

STUDY DESIGN

Controlled in vitro study is the design type.

METHODS

The nucleus pulposus was excised from 12 bovine tail intervertebral discs and monolayer cell cultures were generated. The cultures were divided into four sample groups and incubated in either standard cell culture medium (control group) or medium supplemented with the test substances. The dose rate was adapted based on a total dose of 3 mL iopamidol, 1 mL lidocaine, and 10 mg cortisone per nucleus pulposus. Cell count, viability, proliferation, and differentiation features were analyzed. The study was supported by DePuy. No conflicts of interest arise from this support.

RESULTS

After 24 hours, a significant decrease in cell counts was observed in all three test groups. Population doubling time was 16 hours in the control group cultured in standard medium and increased to 21 hours (cortisone), 25 hours (iopamidol), and 38 hours (lidocaine) after incubation in discography medication (p<.001). Cell viability was slightly, but not significantly decreased in all medication groups. Cells incubated in Lidocaine were significantly smaller (p<.01) and showed clearly reduced pseudopodia formation. Incubation in lidocaine and iopamidol also significantly reduced glycosaminoglycan synthesis.

CONCLUSION

Although only a small decrease in cell viability was observed in all three substances tested, cell count and proliferation decreased significantly. Incubation in lidocaine inhibited pseudopodia formation and might therefore interfere with intercellular signalling and cell migration. Glycosaminoglycan synthesis was significantly decreased after contact with lidocaine as well as Iopamidol. These observations suggest that all three medications tested might interfere with biological repair mechanisms of the intervertebral disc and therefore contribute to a further degeneration.

Steroid injections in the upper extremity: experienced clinical opinion versus evidence-based practices

A survey regarding upper-extremity steroid injection practices was distributed to all active members of the American Society for Surgery of the Hand (ASSH) and American Shoulder and Elbow Surgeons (ASES) using SurveyMonkey. Response rates for the ASSH and ASES were 26% and 24%, respectively. The potency-adjusted dose of steroid injected for common hand and wrist injections ranged from 0.375 to 133.33 mg and for shoulder injections ranged from 0.375 to 250 mg. These ranges span 356-fold and 667-fold differences, respectively. Potency-adjusted doses differed significantly between steroid types for all injections evaluated in this study. American Society for Surgery of the Hand members gave significantly smaller doses of steroid for the glenohumeral and acromioclavicular joints than ASES members. Only 9% of respondents based injection practice on a scientific reference. Sixteen percent of ASSH and 31% of ASES respondents reported no specific rationale for their steroid injection practice; 78% of ASSH and 52% of ASES respondents attributed their rationale to some kind of instruction from their mentors or colleagues. Upper-extremity surgeons demonstrate substantial variability in their practice of steroid injections, with up to a 667-fold range in steroid dose. Experienced clinical opinion is the principal rationale for these injection practices; little rationale is based on formal scientific evidence.

The effect of local anaesthetics on synoviocytes: a possible indirect mechanism of chondrolysis

PURPOSE

While the effect of local anaesthetics on chondrocyte viability is widely documented, the effect of these medications on synoviocytes is largely unknown. The purpose of this study was to understand the effect of 0.5 % bupivacaine and 0.5 % bupivacaine with epinephrine on synoviocyte viability, cytokine and growth factor release, and breakdown product formation.

METHODS

Rabbit fibroblast-like synoviocyte (Type B) cultures were perfused with 0.5 % bupivacaine or 0.5 % bupivacaine with epinephrine (1:200,000) for 24 h. Cell viability was evaluated using a two-colour fluorescence assay. The supernatant was analysed using multiplex inflammatory and matrix metalloproteinase assays.

RESULTS

Synoviocytes treated for 24 h with 0.5 % bupivacaine with epinephrine demonstrated a significant decrease in viability (31.3 ± 19.4 % cell death) when compared with synoviocytes cultured in control media (3.8 ± 1.3 % cell death, p = 0.000) and those cultured in 0.5 % bupivacaine alone (12.6 ± 11.1 % cell death, p = 0.003). No significant decrease in cell viability was observed in synoviocytes treated with 0.5 % bupivacaine compared to those in control media (12.6 ± 11.1 % vs 3.8 ± 1.3 % cell death, p = 0.194). Significantly greater amounts of MMP-1 (47.0 ± 9.2 pg/ml) and MMP-3 (250.0 ± 68.8 pg/ml) were observed in 0.5 % bupivacaine cultures compared with controls (14.3 ± 14.3, p = 0.023 and 72.0 ± 84.9, p = 0.045, respectively).

CONCLUSIONS

0.5 % bupivacaine with epinephrine caused a significant increase in cell death of the synoviocytes, while 0.5 % bupivacaine alone produced cell injury and a significant release of matrix metalloproteinases, which may also lead to indirect injury of the surrounding chondrocytes. These results may help explain the onset of chondrolysis observed in patients who have been treated with intra-articular local anaesthetics.

Knee osteoarthritis in women

Osteoarthritis is a disease that progresses over time and culminates in the destruction of articular cartilage and joints. Thus, with an increasing elderly population the treatment of knee osteoarthritis has become a major healthcare issue. It has been shown that women are more severely impacted by knee osteoarthritis. Differences in knee anatomy, kinematics, previous knee injury, and hormonal influences may play a role. Sex difference with respect to osteoarthritis presentation, treatment, and the allocation of resources also exists. In general, women present for treatment in more advanced stages of osteoarthritis and have more debilitating pain than their male counterparts. In addition, healthcare providers are more likely to recommend total joint arthroplasty for their male patients. Understanding how and why these gender differences occur is instrumental in formulating an inclusive strategy for combating osteoarthritis in the future.

Local anaesthetics and chondrotoxicty: What is the evidence?

PURPOSE

Recent reports have suggested that local anaesthetic agents have a toxic effect on articular chondrocytes. This is despite the widespread intra-articular use of local anaesthetic agents following arthroscopic procedures for a number of years.

METHODS

We have reviewed the available basic science literature focusing on the studies assessing the effect of exposing articular chondrocytes to local anaesthetic agents. We attempt to highlight the key findings and, where possible, extrapolate the laboratory findings to the operating theatre.

RESULTS

Basic science reports are analysed according to their setting of either in vitro, ex vivo or in vivo and according to cell line. A majority of work to date has been done using in vitro models. Only a small number of in vivo models using animal cell lines have been used and the best of these have conflicting results with regard lasting toxicity secondary to local anaesthetic exposure.

CONCLUSIONS

Numerous reports suggest a toxic effect of local anaesthetic agents on articular chondrocytes, however, further work is warranted to establish the precise mechanism of toxicity and whether or not single bolus administration results in long-term deleterious outcomes. Determining the ideal in vitro model will help in extrapolating laboratory data to the operating theatre.

The efficacy of intra-articular injections for pain control following the closed reduction and percutaneous pinning of pediatric supracondylar humeral fractures: a randomized controlled trial

BACKGROUND

The purpose of this single-blinded, randomized, controlled trial was to compare the analgesic efficacy of intra-articular injections of bupivacaine or ropivacaine with that of no injection for postoperative pain control after the operative treatment of supracondylar humeral fractures in a pediatric population.

METHODS

Subjects (n=124) were randomized to treatment with 0.25% bupivacaine (Group B) (n=42), 0.20% ropivacaine (Group R) (n=39), or no injection (Group C) (n=43). The opioid doses and the times of administration as well as child-reported pain severity (Faces Pain Scale-Revised) and parent-reported pain severity (Total Quality Pain Management survey) were recorded.

RESULTS

The proportion of subjects who required morphine and/or fentanyl injections was significantly (p=0.004) lower in Group B (10%) as compared with Group R (36%) and Group C (44%). On the basis of the log-rank test, the opioid-free survival rates were significantly greater in Group B as compared to Groups C and R. Total opioid consumption (morphine equivalent mg/kg) in the first seventy-two hours postoperatively was significantly less in Group B as compared with Group C (mean difference, 0.225; [95% confidence interval (CI), 0.0152 to 0.435]; p=0.036). Parent-reported pain scores were also significantly lower in Group B as compared with both Group C (mean difference, 1.81 [95% CI, 0.38 to 3.25]; p=0.014) and Group R (mean difference, 1.66; 95% CI, 0.20 to 3.12; p=0.027). There were no significant differences across the three groups in terms of self-reported pain. Differences between Groups R and C were not significant for any of the outcome variables.

CONCLUSIONS

The intra-articular injection of 0.25% bupivacaine significantly improves postoperative pain control following the closed reduction and percutaneous pinning of supracondylar humeral fractures in pediatric patients.