Increasing the osmolarity of joint irrigation solutions may avoid injury to cartilage: a pilot study

Making the Case for Hyperosmolar Saline Arthroscopic Irrigation Fluids: A Systematic Review of Basic Science, Translational, and Clinical Evidence

Commonly used isotonic arthroscopic irrigation fluids, such as normal saline or lactated Ringer's, were initially formulated for intravenous administration so they do not replicate the physiologic properties of healthy synovial fluid. Synovial fluid plays an important role in regulating joint homeostasis such that even transient disruptions in its composition and physiology can be detrimental. Previous studies suggest that hyperosmolar solutions may be a promising alternative to traditional isotonic fluids. This manuscript sought to systematically review and synthesize previously published basic science, translational, and clinical studies on the use of hyperosmolar arthroscopic irrigation fluids to delineate the optimal fluid for clinical use. A systematic literature search of MEDLINE/PubMed and Embase databases was performed in accordance with Preferred Reporting Items for Systemic Reviews and Meta-analyses (PRISMA) guidelines. The search phrases were: ("cartilage" AND "hyperosmolar"); ("arthroscopy" OR "arthroscopic" AND "hyperosmolar"). The titles, abstracts, and full texts were screened for studies on hyperosmolar solutions and articular cartilage. Study quality was assessed, and relevant data were collected. A meta-analysis was not performed due to study heterogeneity. A risk of bias assessment was performed on the included translational and clinical studies. There were 10 basic science studies, 2 studies performed in translational animal models, and 2 clinical studies included in this review. Of the basic science studies, 7 utilized a mechanical injury model. The translational studies were carried out in the canine shoulder and equine stifle (knee) joint. Clinical studies were performed in the shoulder and knee. Multiple basic science, translational, and clinical studies highlight the short-term safety, cost-effectiveness, and potential benefits associated with use of hyperosmolar solutions for arthroscopic irrigation. Further work is needed to develop and validate the ideal formulation for a hyperosmolar irrigation solution with proven long-term benefits for patients undergoing arthroscopic surgeries.

Response of Articular Cartilage to Hyperosmolar Stress: Report of an Ex Vivo Injury Model

BACKGROUND

Physiological 0.9% saline is commonly used as an irrigation fluid in modern arthroscopy. There is a growing body of evidence that a hyperosmolar saline solution has chondroprotective effects, especially if iatrogenic injury occurs.

PURPOSE

To (1) corroborate the superiority of a hyperosmolar saline solution regarding chondrocyte survival after mechanical injury and (2) observe the modulatory response of articular cartilage to osmotic stress and injury.

STUDY DESIGN

Controlled laboratory study.

METHODS

Osteochondral explants were isolated from bovine stifle joints and exposed to either 0.9% saline (308 mOsm) or hyperosmolar saline (600 mOsm) and then damaged with a sharp dermatome blade to attain a confined full-thickness cartilage injury site, incubated in the same fluids for another 3 hours, and transferred to chondropermissive medium for further culture for 1 week. Chondrocyte survival was assessed by confocal imaging, while the cellular response was evaluated over 1 week by relative gene expression for apoptotic and inflammatory markers and mediator release into the medium.

RESULTS

The full-thickness cartilage cut resulted in a confined zone of cell death that mainly affected superficial zone chondrocytes. Injured samples that were exposed to hyperosmolar saline showed less expansion of cell death in both the axial (P < .007) and the coronal (P < .004) plane. There was no progression of cell death during the following week of culture. Histological assessment revealed an intact cartilage matrix and normal chondrocyte morphology. Inflammatory and proapoptotic genes were upregulated on the first days postexposure with a notable downregulation toward day 7. Mediator release into the medium was concentrated on day 3.

CONCLUSION

This in vitro cartilage injury model provides further evidence for the chondroprotective effect of a hyperosmolar saline irrigation fluid, as well as novel data on the capability of articular cartilage to quickly regain joint homeostasis after osmotic stress and injury.

CLINICAL RELEVANCE

Raising the osmolarity of an irrigating solution may be a simple and safe strategy to protect articular cartilage during arthroscopic surgery.

Osmolarity-Induced Altered Intracellular Molecular Crowding Drives Osteoarthritis Pathology

Osteoarthritis (OA) is a multifactorial degenerative joint disease of which the underlying mechanisms are yet to be fully understood. At the molecular level, multiple factors including altered signaling pathways, epigenetics, metabolic imbalance, extracellular matrix degradation, production of matrix metalloproteinases, and inflammatory cytokines, are known to play a detrimental role in OA. However, these factors do not initiate OA, but are mediators or consequences of the disease, while many other factors causing the etiology of OA are still unknown. Here, it is revealed that microenvironmental osmolarity can induce and reverse osteoarthritis-related behavior of chondrocytes via altered intracellular molecular crowding, which represents a previously unknown mechanism underlying OA pathophysiology. Decreased intracellular crowding is associated with increased sensitivity to proinflammatory triggers and decreased responsiveness to anabolic stimuli. OA-induced lowered intracellular molecular crowding could be renormalized via exposure to higher extracellular osmolarity such as those found in healthy joints, which reverse OA chondrocyte's sensitivity to catabolic stimuli as well as its glycolytic metabolism.

Microscale investigation of the anisotropic swelling of cartilage tissue and cells in response to hypo-osmotic challenges

Tissue swelling represents an early sign of osteoarthritis, reflecting osmolarity changes from iso- to hypo-osmotic in the diseased joints. Increased tissue hydration may drive cell swelling. The opposing cartilages in a joint may swell differently, thereby predisposing the more swollen cartilage and cells to mechanical injuries. However, our understanding of the tissue-cell interdependence in osmotically loaded joints is limited as tissue and cell swellings have been studied separately. Here, we measured tissue and cell responses of opposing patellar (PAT) and femoral groove (FG) cartilages in lapine knees exposed to an extreme hypo-osmotic challenge. We found that the tissue matrix and most cells swelled during the hypo-osmotic challenge, but to a different extent (tissue: <3%, cells: 11%-15%). Swelling-induced tissue strains were anisotropic, showing 2%-4% stretch and 1%-2% compression along the first and third principal directions, respectively. These strains were amplified by 5-8 times in the cells. Interestingly, the first principal strains of tissue and cells occurred in different directions (60-61° for tissue vs. 8-13° for cells), suggesting different mechanisms causing volume expansion in the tissue and the cells. Instead of the continuous swelling observed in the tissue matrix, >88% of cells underwent regulatory volume decrease to return to their pre-osmotic challenge volumes. Cell shapes changed in the early phase of swelling but stayed constant thereafter. Kinematic changes to tissue and cells were larger for PAT cartilage than for FG cartilage. We conclude that the swelling-induced deformation of tissue and cells is anisotropic. Cells actively restored volume independent of the surrounding tissues and seemed to prioritize volume restoration over shape restoration. Our findings shed light on tissue-cell interdependence in changing osmotic environments that is crucial for cell mechano-transduction in swollen/diseased tissues.

Prospective Randomized Controlled Clinical Trial Comparing Hyperosmolar Saline to Standard Isotonic Irrigation Fluid for Arthroscopic Knee Surgery: Initial Clinical Outcomes

Numerous in vitro studies suggest higher osmolarity irrigation fluids potentiate a chondroprotective environment, and a recent clinical study using hyperosmolar saline for shoulder arthroscopy reported potential clinical advantages. This prospective randomized double-blind controlled clinical trial was designed to assess initial clinical outcomes associated with use of a hyperosmolar irrigation solution in patients undergoing arthroscopic knee surgery. With institutional review board approval and informed consent, patients scheduled for arthroscopic knee surgery were randomized to surgery with either isotonic lactated Ringer's (273 mOsm/L) or hyperosmolar saline (593 mOsm/L) irrigation solution. Outcomes included perioperative blood pressure, knee girth, visual analogue scale (VAS) pain scores, and narcotic pain medication consumption. Forty-six patients underwent arthroscopic knee surgery with isotonic (n = 23) or hyperosmolar (n = 23) irrigation fluids. There were 11 males and 12 females (mean age = 44.0 years) in the isotonic cohort and 8 males and 15 females (mean age = 40.2 years) in the hyperosmolar cohort. There were no significant differences with respect to surgical duration (pump time) or amount of irrigation fluid used between the two cohorts. There were no significant differences with respect to change in knee girth, blood pressure, or VAS pain scores. However, patients treated with hyperosmolar saline consumed less narcotic medication on postoperative day 3 (4.0 ± 7.6 vs. 15.5 ± 17.4 mg, p = 0.01). The results of this randomized clinical trial suggest that a hyperosmolar irrigation solution is safe and relatively inexpensive for use in patients undergoing arthroscopic knee surgery and contributes to a reduction in initial postoperative narcotic pain medication consumption. A hyperosmolar saline irrigation fluid was not associated with any detrimental effects on the execution of the surgical procedure, postoperative pain, or periarticular fluid extravasation. Taken together with previous basic science, translational, and clinical studies, hyperosmolar saline irrigation fluid is promising alternative to traditional isotonic irrigation fluids for knee arthroscopy. This study is a prospective trial and reflects level of evidence I.

A Hyperosmolar Saline Solution Fortified with Anti-Inflammatory Components Mitigates Articular Cartilage Pro-Inflammatory and Degradative Responses in an In Vitro Model of Knee Arthroscopy

OBJECTIVE

To evaluate differences in pro-inflammatory and degradative mediator production from osteoarthritic knee articular cartilage explants treated with a hyperosmolar saline solution supplemented with anti-inflammatory components (l-glutamine, ascorbic acid, sodium pyruvate, epigallocatechin gallate [EGCG], and dexamethasone) or normal saline using an in vitro model for knee arthroscopy.

DESIGN

Full-thickness 6 mm articular cartilage explants (n = 12/patient) were created from femoral condyle and tibial plateau samples collected from patients who received knee arthroplasty. One explant half was treated for 3 hours with hyperosmolar saline (600 mOsm/L) supplemented with anti-inflammatory components and the corresponding half with normal saline (308 mOsm/L). Explants were cultured for 3 days and then collected for biomarker analyses. Media biomarker concentrations were normalized to the wet weight of the tissue (mg) and were analyzed by a paired t test with significance set at P < 0.05.

RESULTS

Cartilage was collected from 9 females and 2 males (mean age = 68 years). Concentrations of MCP-1 (P < 0.001), IL-8 (P = 0.03), GRO-α (P = 0.02), MMP-1 (P < 0.001), MMP-2 (P < 0.001), and MMP-3 (P < 0.001) were significantly lower in explant halves treated with the enhanced hyperosmolar solution. When considering only those cartilage explants in the top tercile of tissue metabolism, IL-6 (P = 0.005), IL-8 (P = 0.0001), MCP-1 (P < 0.001), GRO-α (P = 0.0003), MMP-1 (P < 0.001), MMP-2 (P < 0.001), MMP-3 (P < 0.001), and GAG expression (P = 0.0001) was significantly lower in cartilage explant halves treated with the enhanced hyperosmolar solution.

CONCLUSIONS

Treatment of cartilage explants with a hyperosmolar saline arthroscopic irrigation solution supplemented with anti-inflammatory components was associated with significant decreases in inflammatory and degradative mediator production and mitigation of proteoglycan loss.

Pulmonary edema following shoulder arthroscopy under general anesthesia with nerve block: An observational study

ABSTRACT

Shoulder arthroscopy requires a large of irrigation for a better surgical view, leading circulatory overload. This study was performed to prove whether pulmonary edema will be lead by a large of irrigation.General anesthesia with interscalene block was induced before operation. The primary outcome was ultrasound evaluation of B lines from the time before nerve block to the time 10 hours after operation. The secondary outcomes included oxygenation index, arterial partial pressure of carbon dioxide, visual analogue scale, muscle strength grade.A total of 93 patients were evaluated. Before surgery, B lines failed to be detected. While the highest total incidence of B lines was 49.4%, occurred at 4 hours after surgery. The highest incidences of severe and moderate pulmonary edema were 3.2% (P = .081) and 9.7% (P = .002), respectively. B lines were also found on both the affected and healthy side. During operation, the incidence of type 1 respiratory failure was 5.4% (P = .023) and that of both type 1 and 2 respiratory failure were 6.5% (P = .013). Pain was relieved in 6 hours after surgery (VAS < 3). At 12 hours after operation, the VAS of resting and motion were 4.68 ± 2.27, 6.90 ± 2.43, respectively. While the grade of muscle strength was 4.48 ± 0.51 at 12 hours after operation.There is a high incidence of pulmonary edema in shoulder arthroscopy, and ultrasound is a convenient tool to evaluate this complication. Pain is relieved in 6 hours after surgery by nerve block. While muscle strength can also recover at 12 hours after surgery.

Use of a Hyperosmolar Saline Solution to Mitigate Proinflammatory and Degradative Responses of Articular Cartilage and Meniscus for Application to Arthroscopic Surgery

PURPOSE

This study was designed to evaluate differences in proinflammatory and degradative mediator production and extracellular matrix degradation from osteoarthritic knee articular cartilage and meniscus explants treated with either hyperosmolar saline or isotonic saline.

METHODS

6 mm-diameter full-thickness explants were created from articular cartilage and menisci recovered after patients underwent knee surgery. One explant half was treated for 3 hours with hyperosmolar saline (600 mOsm/L) and the corresponding half with isotonic saline (300 mOsm/L). Explants were subsequently cultured for 3 days in tissue culture media. On day 3, media were collected for biomarker analyses. Results were normalized to tissue wet weight and analyzed statistically.

RESULTS

Articular cartilage was collected from 10 patients (5 male, 5 female; mean age = 66.9 years) and menisci were collected from 8 patients (2 male, 6 female; mean age = 66 years). Articular cartilage media concentrations of monocyte chemoattractant protein-1 (P = .001) and interleukin (IL)-6 (P = .049) were significantly lower in explants treated with hyperosmolar saline. Meniscus media concentrations of prostaglandin E₂ (P = .008), monocyte chemoattractant protein-1 (P = .011), IL-6 (P = .029), IL-8 (P = .012), matrix metalloproteinase-2 (P = .011), and glycosaminoglycan (P = .008) were significantly lower in explants treated with hyperosmolar saline.

CONCLUSIONS

Treatment of cartilage and meniscus explants with hyperosmolar saline effectively mitigated key proinflammatory mediator production, as well as degradative mediator production and glycosaminoglycan loss from meniscus, with no detrimental effects noted compared to isotonic saline.

CLINICAL RELEVANCE

These results suggest that hyperosmolar saline irrigation fluid may provide a safe alternative to standard isotonic saline irrigation fluid, and could mitigate untoward effects associated with inflammatory responses after standard-of-care knee arthroscopy.

Optimizing the Composition of Irrigation Fluid to Reduce the Potency of Staphylococcus aureus α-Toxin: Potential Role in the Treatment of Septic Arthritis

OBJECTIVE

Septic arthritis is commonly caused by Staphylococcus aureus and is a medical emergency requiring antibiotics and joint irrigation. The bacteria produce α-toxin causing rapid cartilage cell (chondrocyte) death. Saline (0.9%NaCl) lavage is normally used to remove bacteria and toxins, however, its composition might be suboptimal to suppress the lethal effects of α-toxin. We utilized rabbit erythrocyte hemolysis as a sensitive, biologically relevant assay of α-toxin levels to determine if changes to osmolarity, temperature, pH, and divalent cation (Mg²⁺, Ca²⁺) concentration were protective.

DESIGN

Erythrocytes were incubated in the various conditions and then exposed to α-toxin ("chronic" challenge) or incubated with α-toxin and then exposed to experimental conditions ("acute" challenge).

RESULTS

Raising osmolarity from 300 mOsm (0.9%NaCl) to 400, 600, or 900 mOsm (sucrose addition) when applied chronically, significantly reduced hemolysis linearly. As an acute challenge, osmotic protection was significant and similar over 400 to 900 mOsm. Reducing temperature chronically from 37°C to 25°C and 4°C significantly reduced hemolysis, however, when applied as an acute challenge although significant, was less marked. Divalent cations (Mg²⁺, Ca²⁺ at 5mM) reduced hemolysis. Varying pH (6.5, 7.2, 8.0) applied chronically marginally reduced hemolysis. The optimized saline (0.9% NaCl; 900 mOsm with sucrose, 5 mM MgCl₂ (37°C)) rapidly and significantly reduced hemolysis compared with saline and Hank's buffered saline solution applied either chronically or acutely.

CONCLUSIONS

These results on the effect of S. aureus α-toxin on erythrocytes showed that optimizing saline could markedly reduce the potency of S. aureus α-toxin. Such modifications to saline could be of benefit during joint irrigation for septic arthritis.

Damage control articular surgery: Maintaining chondrocyte health and minimising iatrogenic injury

Articular cartilage has limited intrinsic regenerative potential. The maintenance of healthy articular cartilage is essential to prevent joint degeneration and the morbidity associated with arthritis. In this review, we outline the structure and function of healthy articular cartilage. We summarise some of the recent literature outlining the influence of surgical factors on chondrocyte health. These factors include mechanical injury from instrumentation and drilling, drying, and the influence of irrigation fluids, antimicrobial solutions and local anaesthetics. We demonstrate that there is scope for improving cartilage viability at the time of surgery if simple chondroprotective measures are routinely adopted.

Interferon-Gamma Stimulated Murine Macrophages In Vitro: Impact of Ionic Composition and Osmolarity and Therapeutic Implications

Background: Injections of osmolytes are promising immunomodulatory treatments for medical benefit, although the rationale and underlying mechanisms are often lacking. The goals of the present study were twofold: (1) to clarify the anti-inflammatory role of the potassium ion and (2) to begin to decouple the effects that ionic strength, ionic species, and osmolarity have on macrophage biology. Materials and Methods: RAW 264.7 murine macrophages were encapsulated in three-dimensional, poly(ethylene glycol) diacrylate hydrogels and activated with interferon-gamma to yield M(IFN). Gene and protein profiles were made of M(IFN) exposed to different hyperosmolar treatments (80 mM potassium gluconate, 80 mM sodium gluconate, and 160 mM sucrose). Results: Relative to M(IFN), all hyperosmolar treatments suppressed expression of pro-inflammatory markers (nitric oxide synthase-2 [NOS-2], tumor necrosis factor-alpha, monocyte chemoattractant protein-1 [MCP-1]) and increased messenger RNA (mRNA) expression of the pleiotropic and angiogenic markers interleukin-6 (IL-6) and vascular endothelial growth factor-A (VEGF), respectively. Ionic osmolytes also demonstrated a greater level of change compared to the nonionic treatments, with mRNA levels of IL-6 the most significantly affected. M(IFN) exposed to K+ exhibited the lowest levels of NOS-2 and MCP-1, and this ion limited IL-6 release induced by osmolarity. Conclusion: Cumulatively, these data suggest that osmolyte composition, ionic strength, and osmolarity are all parameters that can influence therapeutic outcomes. Future work is necessary to further decouple and mechanistically understand the influence that these biophysical parameters have on cell biology, including their impact on other macrophage functions, intracellular osmolyte composition, and cellular and organellular membrane potentials.

An in vitro study of the effect of the optimal irrigation solution conditions during canine articular surgery

OBJECTIVES

To establish whether chondrocyte viability, matrix degradation and the induction of proteolytic gene expression in canine cartilage is independent of irrigation fluid osmolality and time following exposure to the irrigation fluid.

METHODS

Canine cartilage explants were exposed to one of three different solution types i) Culture medium (270-280 mOsmol/kg) ii) NaCl 0.9% (302 mOsmol/kg) iii) NaCl 0.9% with sucrose (600 mOsmol/kg). Chondrocyte viability and selected proteolytic gene expression were measured at two time points; immediately following exposure and 24 h following exposure. The media samples at 24 h following exposure were assessed for sulphated glycosaminoglycan (sGAG) release.

RESULTS

In all samples, no cell death was observed across the superficial or deeper layers of the cartilage. When adjusting for time, gene expression was not shown to be dependent on solution type. However for all solution types, Matrix Metalloproteinase 13 (MMP13) and A Disintegrin and Metalloproteinase with Thrombospondin Motifs 5 (ADAMTS5) expression was significantly decreased in cartilage samples at 24 h post exposure comparatively to samples tested immediately post exposure. No significant differences were identified in the relative sGAG release between the solution types.

CLINICAL SIGNIFCANCE

Arthroscopic solution irrigation of cartilage explants had no effect on cell viability or proteinase production. At present there is no indication to optimise irrigation fluid osmolarity, as conventional arthroscopic solution was not deleterious to healthy cartilage in this model.

Electrical Characterization of Pork Tissue Measured by a Monopolar Injection Needle and Discrete Fourier Transform based Impedance Measurement

Ultrasonography or fluoroscopy-guided needle injection has been used for intra-articular injection therapy against adhesive capsulitis and joint diseases. To improve the image-guided intra-articular injection therapy, electrical impedance measurement based positioning of the needle tip in the target tissue can be applied. The feasibility of the discrimination for the tissue layer at which the disposable monopolar injection needle tip position was investigated using the discrete Fourier transform (DFT)-based impedance measurement system and the ultrasound imaging device. The electrical impedance spectra of the pork tissue measured in the frequency range of 200 Hz to 50 kHz were characterized by designed equivalent circuit modeling analysis. The normalized impedance data of the tissue layers (dermis, hypodermis, and muscle) were significantly different from each other (p-value < 0.001). The DFT-based impedance measurement system with a monopolar injection needle can be complementary to the image-guided intra-articular injection therapy.

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.

Hyperosmolar Potassium (K+) Treatment Suppresses Osteoarthritic Chondrocyte Catabolic and Inflammatory Protein Production in a 3-Dimensional In Vitro Model

OBJECTIVE

The main goal of this study was to provide a proof-of-concept demonstrating that hyperosmolar K⁺ solutions can limit production of catabolic and inflammatory mediators in human osteoarthritic chondrocytes (OACs).

METHODS

A 3-dimensional in vitro model with poly(ethylene glycol) diacrylate (PEGDA) hydrogels was used. Catabolic and pro-inflammatory protein production from encapsulated OACs was assessed following culture for 1 or 7 days in the presence or absence of 80 mM K⁺ gluconate, 80 mM sodium (Na⁺) gluconate, or 160 mM sucrose, each added to culture media (final osmolarity ~490 mOsm).

RESULTS

Relative to untreated controls, OACs treated with hyperosmolar (80 mM Na⁺ gluconate or 160 mM sucrose) solutions produced lower levels of catabolic and inflammatory mediators in a marker- and time-dependent manner (i.e., MMP-9 after 1 day; MCP-1 after 7 days ( P ≤ 0.015)). In contrast, OAC treatment with 80 mM K⁺ gluconate reduced catabolic and inflammatory mediators to a greater extent (both the number of markers and degree of suppression) relative to untreated, Na⁺ gluconate, or sucrose controls (i.e., MMP-3, -9, -13, TIMP-1, MCP-1, and IL-8 after 1 day; MMP-1, -3, -9, -13, TIMP-1, MCP-1, and IL-8 after 7 days ( P ≤ 0.029).

CONCLUSIONS

Hyperosmolar K⁺ solutions are capable of attenuating protein production of catabolic and inflammatory OA markers, providing the proof-of-concept needed for further development of a K⁺-based intra-articular injection for OA treatment. Moreover, K⁺ performed significantly better than Na⁺- or sucrose-based solutions, supporting the application of K⁺ toward improving irrigation solutions for joint surgery.

Low pH irrigation fluids have positive effect on intra-articular chondral healing

PURPOSE

The aim of this study was to evaluate the effect of Ringer's lactate (RL) solutions with different pH values on early histologic healing in a microfracture model in vivo. The null hypothesis of the presented study is that irrigation fluids with lower pH (6.4) have negative effects on fibrous cartilage healing.

METHODS

Eighteen Wistar albino rats were randomly divided into three groups. Anterior midline incision was performed. Microfracture procedure was performed with a 1.2 mm k-wire at the lateral femoral condyle of each knee. the skin was sutured and joints were irrigated for 30 min with low pH (6.4) RL in Group 1, high pH (7.6) RL in Group 2 and no irrigation in Group 3. Three rats from each group were randomly selected and killed on the 3rd and 7th day. On the 3rd day, the healed chondral area was examined. On the 3rd and 7th day, the chondral depth and morphology were evaluated. On the 7th day, bone cellularity was assessed with osteoblast; osteoclast number and bone quality were evaluated with trabecular area and the number of trabeculae.

RESULTS

Chondral healing area on the 3rd day was significantly higher in Group 1 compared to other groups. Chondral morphology was also qualitatively superior in Group 1 compared to other groups on the 3rd and 7th day. There were no differences in chondral depths between the groups on the 3rd day; however, increased chondral depths were observed in Group 1 on the 7th day. There were statistically significant increases in trabecular area and the number of trabeculae, as well as the number of osteoblasts and osteoclasts in Group 1 on the 7th day.

CONCLUSIONS

The presented study revealed that low pH irrigation fluids have positive effects on the healing characteristics of intra-articular fibrous cartilage after microfracture procedure in vivo. In light of this study, we can assume that lower pH solutions could be safely used during microfracture procedures and it can also facilitate intra-articular fibrous cartilage formation and cartilage healing. Selection of irrigation solution is also important for intra-articular fibrous cartilage healing after microfracture procedure in vivo.

The influence of the irrigating solution on articular cartilage in arthroscopic surgery: A systematic review

Purpose

Arthroscopic surgery has become an important and popular orthopedic procedure for numerous joint disorders. Continuous irrigation is performed to replace synovial fluid for optimal joint distension and clear visualization of the synovial cavity. Irrigation solutions may, however, negatively impact articular cartilage and chondrocyte viability. This systematic review aims to compare different irrigating solutions and their properties to determine whether one is superior in its effects on articular cartilage and chondrocytes.

Methods

A systematic literature review was conducted. The online databases: Embase, Medline, HealthStar, Emcare and PubMed were searched from 1946 to August 2018. Methodological index for non-randomized studies (MINORS) was used to assess methodological quality of the included studies.

Results

Sixteen studies met the inclusion/exclusion criteria and were included in this review. Although the studies used different criteria to define superiority, solution superiority was based on results that focused on articular cartilage and chondrocyte viability. Seven of the sixteen included studies compared Ringer's/lactate solution or Ringer's lactate to normal saline. Three found Ringer's solution or Ringer's lactate to be superior to saline, whereas, three studies found no significant differences and one study found Ringer's lactate to be inferior to saline only when their osmolarities differed. Four studies compared ionic to non-ionic solutions. Two of the four studies demonstrated non-ionic solutions to be superior, one had demonstrated no significant differences between solutions, while one had mixed results. Six of the sixteen included studies compared differing osmolarities. One found no statistically significant differences between solutions of differing osmolarities, whereas, the remaining five studies found superiority with hyperosmolarity. Two of the sixteen included studies examined the effects of different temperatures. Both studies concluded that the use of a warmer (more physiological) temperature is more ideal. Two of the sixteen studies included in this review compared solutions with differing pH levels. Both studies concluded on the importance of utilizing the more physiological solutions for arthroscopic procedures.

Conclusion

Ringer's Lactate and Ringer's Solution as well as non-ionic solutions may have merit over the use of the normal saline for irrigation. Hyperosmolarity, warmer solutions and ones with more physiological pH values may be beneficial when considering potential effects on articular cartilage and chondrocytes. The current review demonstrated trends found in the current literature, which require human studies - preferably high quality RCTs -to make recommendations that aid surgeons in making the best decision regarding the ideal irrigation solution to use on their patients.

Level of evidence

Level IV, Systematic review of Level IV studies.

Total Knee Arthroplasty in Patients With Prior Anterior Cruciate Ligament Reconstruction

BACKGROUND

Few studies have analyzed the outcomes of total knee arthroplasty (TKA) in patients with prior anterior cruciate ligament (ACL) reconstruction, and the reported outcomes are controversial. The purpose of this study is to assess if prior ACL reconstruction had any impact on the outcome of subsequent TKA.

METHODS

A matched case-control study was conducted in patients who underwent TKA, including 37 with prior ACL reconstruction and 37 patients without ACL reconstruction. Preoperative and postoperative clinical and radiological data were collected from a prospective arthroplasty database with a minimum follow-up of 5 years. The mean age was 69.6 years, and 59.4% were men. The Knee Society scores, Short Form-12, and Western Ontario and McMaster Universities questionnaires were used for functional evaluations. Visual analogue scale 0-10 was used for patient satisfaction.

RESULTS

The mean follow-up after TKA was 6.1 (range 5-7.3) years. Two patients in the ACL group developed knee stiffness requiring manipulation under anesthesia, while 1 patient in the control group suffered superficial wound infection. At last follow-up, no significant differences in functional or radiologic outcomes were found between both groups. The performance of TKA in ACL patients had increased technical difficulty and significantly longer time of surgery, but this had no influence on the outcomes. In the ACL group, 24 knees had technical difficulty in surgery. The main difficulty in most ACL patients was due to varus deformity and increased retraction of the medial soft structures which required progressive medial release. Other 2 knees had difficult knee exposure. One was an unexpected partial patellar tendon avulsion and the other required planned quadriceps snip.

CONCLUSION

TKA was an effective procedure for patients with prior ACL reconstruction. The surgeon should be warned of the possible difficulties in the knee exposure and possible need of medial release to obtain an appropriate ligament balance. However, these additional procedures had no negative effect on the outcomes of TKA.

Safety and efficacy of hyperosmolar irrigation solution in shoulder arthroscopy

BACKGROUND

A hyperosmolar irrigation solution has been reported to be safe and have potential benefits for use during shoulder arthroscopy in an animal model study. In this study, the clinical effects of a hyperosmolar solution were compared with a standard isotonic solution when used for shoulder arthroscopy.

METHODS

A prospective, double-blind, randomized controlled trial was performed to compare isotonic (273 mOsm/L) and hyperosmolar (593 mOsm/L) irrigation solutions used for arthroscopic rotator cuff repair. Primary outcomes focused on the amount of periarticular fluid retention based on net weight gain, change in shoulder girth, and pain. All patients were tracked through standard postsurgical follow-up to ensure no additional complications arose. Patients were contacted at 1 year to assess American Shoulder and Elbow Surgeon score, visual analog scale pain score, and the Single Assessment Numeric Evaluation shoulder scores RESULTS: Fifty patients (n = 25/group) were enrolled and completed the study. No statistically significant differences were noted between cohorts in demographics or surgical variables. The hyperosmolar group experienced significantly less mean weight gain (1.6 ± 0.82 kg vs. 2.25 ± 0.77 kg; P = .005), significantly less change in shoulder girth (P < .05), and a significantly lower immediate postoperative visual analog scale pain score (P = .036). At 1 year postoperatively, the differences between groups for American Shoulder and Elbow Surgeons, visual analog scale pain, and Single Assessment Numeric Evaluation were not significant (P > .2).

CONCLUSION

A hyperosmolar irrigation solution provides a safe and effective way to decrease periarticular fluid retention associated with arthroscopic rotator cuff surgery without any adverse long-term effects. Use of a hyperosmolar irrigation solution for shoulder arthroscopy has potential clinical benefits to surgeons and patients.

Elution profiles of tobramycin and vancomycin from high-purity calcium sulphate beads incubated in a range of simulated body fluids

The aim of this study was to characterise the elution profiles of antibiotics in combination with pharmaceutical grade calcium sulphate beads in phosphate buffered saline and other physiological solutions which more closely mimic the in vivo environment. Synthetic recrystallised calcium sulphate was combined with vancomycin hydrochloride powder and tobramycin sulphate solution and the paste was formed into 3 mm diameter hemispherical beads. Then 2 g of beads were immersed in 2 ml of either phosphate buffered saline, Dulbecco's Modified Eagle Medium or Hartmann's solution and incubated at 37℃ for up to 21 days. At a range of time points, eluent was removed for analysis by liquid chromatography-mass spectrometry (LC-MS). Tobramycin sulphate and vancomycin hydrochloride release was successfully quantified against standard curves from solutions eluted in all three physiological media (phosphate buffered saline, Dulbecco's Modified Eagle Medium and Hartmann's solution) during incubation with calcium sulphate beads. One hour eluate concentrations were high, up to 2602 µg/ml for tobramycin in phosphate buffered saline and 7417 µg/ml for vancomycin, whereas in DMEM, the levels of tobramycin were 2458 µg/ml and 4401 µg/ml for vancomycin. The levels in HRT were 2354 µg/ml for tobramycin and 5948 µg/ml for vancomycin. The results show highest levels of antibiotic elution over the first 24 h, which gradually diminish over the following 21 days.

Effects of Cold Irrigation on Early Results after Total Knee Arthroplasty: A Randomized, Double-Blind, Controlled Study

Several studies have indicated that pain peaks at 24 to 48 hours after total knee arthroplasty (TKA) surgery. TKA has been associated with disruption in normal sleep patterns, swelling knee, and significant blood loss. However, a satisfactory regime to resolve these mentioned problems has yet to be found.In this study, a total of 420 patients were randomly allocated into two groups and treated with continuous irrigation of either 4000 mL cold saline with 0.5% epinephrine or normal temperature solution. Clinical outcomes including pain scores at rest during postoperative three days, drainage output, analgesic consumption, decreased hemoglobin, sleep quality, and satisfaction rate were analyzed. Mean scores and postoperative change in scores were calculated.Visual analog scale (VAS) pain scores in the treatment group were significantly reduced from 4 hours (P = 0.0016) to 24 hours (P = 0.0004) after TKA. Additional benefits including reduced analgesic consumption, improved satisfaction rate, and sleep quality were observed. In addition, a significant reduction in blood loss reflected by decreased Hb and drainage was found.In this study, irrigation with a cold 0.5% epinephrine solution was a beneficial and cost-effective treatment that decreased acute postoperative VAS pain scores immediately after and 1 day after surgery. Patients reported postoperative improvement in sleep quality and overall satisfaction rate with a decrease in morphine usage. In addition, a reduction of intraoperative blood loss might decrease the blood transfusion rate and related costs. Collectively, irrigation with cold 0.5% epinephrine offers a safe, simple, and effective treatment that might improve recovery and enhance quality of life of patients undergoing TKA.

Dexamethasone Release from Within Engineered Cartilage as a Chondroprotective Strategy Against Interleukin-1α

While significant progress has been made toward engineering functional cartilage constructs with mechanical properties suitable for in vivo loading, the impact on these grafts of inflammatory cytokines, chemical factors that are elevated with trauma or osteoarthritis, is poorly understood. Previous work has shown dexamethasone to be a critical compound for cultivating cartilage with functional properties, while also providing chondroprotection from proinflammatory cytokines. This study tested the hypothesis that the incorporation of poly(lactic-co-glycolic acid) (PLGA) (75:25) microspheres that release dexamethasone from within chondrocyte-seeded agarose hydrogel constructs would promote development of constructs with functional properties and protect constructs from the deleterious effects of interleukin-1α (IL-1α). After 28 days of growth culture, experimental groups were treated with IL-1α (10 ng/mL) for 7 days. Reaching native equilibrium moduli and proteoglycan levels, dexamethasone-loaded microsphere constructs exhibited tissue properties similar to microsphere-free control constructs cultured in dexamethasone-supplemented culture media and were insensitive to IL-1α exposure. These findings are in stark contrast to constructs containing dexamethasone-free microspheres or no microspheres, cultured without dexamethasone, where IL-1α exposure led to significant tissue degradation. These results support the use of dexamethasone delivery from within engineered cartilage, through biodegradable microspheres, as a strategy to produce mechanically functional tissues that can also combat the deleterious effects of local proinflammatory cytokine exposure.

Hyperosmolar irrigation compared with a standard solution in a canine shoulder arthroscopy model

BACKGROUND

A hyperosmolar irrigation solution may decrease fluid extravasation during arthroscopic procedures. Demonstrating the safety of a hyperosmolar irrigation solution with respect to chondrocyte viability and cartilage water content was deemed necessary before designing a clinical efficacy study.

METHODS

We designed a translational animal model study in which hyperosmolar arthroscopy irrigation fluid (1.8%, 600 mOsm/L) was compared with normal saline (0.9%, 300 mOsm/L). Purpose-bred research dogs (n = 5) underwent bilateral shoulder arthroscopy. Irrigation fluid was delivered to each shoulder joint (n = 10) at 40 mm Hg for 120 minutes using standard ingress and egress portals. The percentage change in shoulder girth was documented at the completion of 120 minutes. Articular cartilage sections from the glenoid and humeral head were harvested from both shoulders. Chondrocyte viability and tissue water content were evaluated. Differences between groups and compared with time 0 controls were determined, with significance set at P <.05.

RESULTS

The mean percentage change in shoulder girth was higher in the isotonic control group (13.3%) than in the hyperosmolar group (10.4%). Chondrocyte viability and tissue water content for glenoid and humeral head cartilage were well maintained in both treatment groups, and differences were not statistically significant.

CONCLUSIONS

The data from this study suggest that doubling the osmolarity of the standard irrigation solution used for arthroscopy was not associated with any detrimental effects on chondrocyte viability or tissue water content after 2 hours of arthroscopic irrigation. On the basis of potential benefits in conjunction with the safety demonstrated in these data, clinical evaluation of a hyperosmolar solution for irrigation during shoulder arthroscopy appears warranted.

The use of hyperosmotic saline for chondroprotection: implications for orthopaedic surgery and cartilage repair

OBJECTIVE

Articular cartilage may experience iatrogenic injury during routine orthopaedic/arthroscopic procedures. This could cause chondrocyte death, leading to cartilage degeneration and posttraumatic osteoarthritis. In an in vitro cartilage injury model, chondrocyte death was reduced by increasing the osmolarity of normal saline (NS), the most commonly-used irrigation solution. Here, we studied the effect of hyperosmolar saline (HS) on chondrocyte viability and cartilage repair in an in vivo injury model.

DESIGN

Cartilage injury was induced by a single scalpel cut along the patellar groove of 8 week old rats in the absence of irrigation or with either NS (300 mOsm) or HS (600 mOsm). The percentage of cell death (PCD) within the injured area was assessed using confocal microscopy. Repair from injury was evaluated by histology/immunostaining, and inflammatory response by histology, cytokine array analysis and ELISA (enzyme-linked immunosorbent assay).

RESULTS

The PCD in saline-irrigated joints was increased compared to non-irrigated (NI) joints [PCD = 20.8% (95%CI; 14.5, 27.1); PCD = 9.14% (95%CI; 6.3, 11.9); P = 0.0017]. However, hyperosmotic saline reduced chondrocyte death compared to NS (PCD = 10.4% (95%CI; 8.5, 12.3) P = 0.0024). Repair score, type II collagen and aggrecan levels, and injury width, were significantly improved with hyperosmotic compared to NS. Mild synovitis and similar changes in serum cytokine profile occurred in all operated joints irrespective of experimental group.

CONCLUSIONS

Hyperosmotic saline significantly reduced the chondrocyte death associated with scalpel-induced injury and enhanced cartilage repair. This irrigation solution might be useful as a simple chondroprotective strategy and may also reduce unintentional cartilage injury during articular reconstructive surgery and promote integrative cartilage repair, thereby reducing the risk of posttraumatic osteoarthritis.

Osmolarity influences chondrocyte repair after injury in human articular cartilage

Background

The purpose was to determine the influence of irrigation solution osmolarity on articular chondrocytes survival and metabolic state following mechanical injury.

Methods

Osteochondral explants were harvested from patients undergoing total knee arthroplasty for osteoarthritis and then cut through their full thickness to establish mechanical injury models. Cartilage explants were incubated in irrigation solutions (saline and balanced salt) with different osmolarities (180, 280, 380, 580 mOsm/L) for 2 h. The percentage of cell death (100 × number of dead cells/number of dead and live cells) was quantified with the laser confocal microscopy. The terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) assay was performed to detect apoptosis index of injured cartilage. The contents of proteoglycan elution were determined by spectrophotometer at 530 nm, and HIF-1α and type II collagen mRNA yields were quantified with real-time PCR.

Results

In situ dead chondrocytes were mainly localized to the superficial tangential region of injured cartilage edge after mechanical injury. The percentage of cell death was decreased, and proteoglycan elution was gradually reduced with the increasing of osmolarity. The apoptosis indices of TUNEL assay in different osmolarities had no significant difference (P = 0.158). HIF-1α and type II collagen mRNA yields were the least for chondrocytes exposed to 180 mOsm/L medium and were the greatest for chondrocytes exposed to 380 mOsm/L medium. Compared with the saline group, the cell death of superficial zone was significantly decreased (P = 0.001) and contents of proteoglycan elution were also significantly decreased (P = 0.045) in the balanced salt. HIF-1α (P = 0.017) and type II collagen (P = 0.034) mRNA yields in the chondrocytes exposed to the balanced salt were significantly more than the saline group.

Conclusion

The osmolarity of irrigation solutions plays an important role in the survival and metabolic state of chondrocytes following mechanical injury, and the chondrocyte death is not caused by apoptosis. Increasing osmolarity of irrigation solutions may be chondroprotective with decreasing the chondrocyte death, reducing inhibition of metabolism and proteoglycan elution, ultimately preventing cartilage degeneration and promoting integrative repair.

The effect of environmental pH change on bovine articular cartilage metabolism: implications for the use of buffered solution during arthroscopy?

PURPOSE

The purpose of this study is to determine the immediate effects of pH change on the metabolism of bovine chondrocytes.

METHODS

Bovine osteochondral explants were pre-cultured and placed in Ringer's lactate solution. Thirty explants were randomly divided into 3 groups. Buffered Ringer's lactate, pH 7.2, was used in Group I; buffered Ringer's lactate, pH 7.4 (normal bovine knee joint pH), was used in Group II; and this group was also set as the control group. Buffered Ringer's lactate, pH 7.6, was used in Group III. All specimens were soaked for 2 h. RNA yield analyses were performed to evaluate the changes in cartilage metabolism at different pH levels.

RESULTS

Mean RNA yields of (hypoxia-induced factor) 1α that were immersed at pH 7.2 and 7.6 were 10.5- and 9.9-fold from base, respectively, which were lower compared to explants at pH 7.4 which was found as 15.2-fold. Mean RNA yields of aggrecan that were immersed at pH 7.2 and 7.6 were 12.2- and 13.6-fold from base, respectively, which were lower compared to explants at pH 7.4 which was found as 20-fold. RNA yields of collagen type II at pH 7.2 and 7.6 were 16.1- and 16.6-fold from base, respectively, which were lower compared to explants immersed at pH 7.4 which was found as 22.1-fold.

CONCLUSION

The findings of the presented study suggest that short-term exposures to both acidic and basic pH may have effects on chondrocyte function. Our findings also indicate that exposures to solutions with a pH different from normal by only 0.2 unit could suppress chondrocyte metabolism and RNA synthesis.

CLINICAL RELEVANCE

Using buffered irrigation solutions with a pH closer to the normal joint pH could be more physiologic and causes less ultra-structural damage than regular irrigation solutions.

LEVEL OF EVIDENCE

II.

Effect of different irrigation fluids on human articular cartilage: an in vitro study

PURPOSE

The goal of this study was to examine the effect of different irrigation fluids on human articular cartilage.

METHODS

Femoral heads were obtained from 9 patients with fractured neck of femur (mean age, 89 years; 7 female) and tibial plateaus from 2 female patients at the time of total knee replacement (mean age, 73 years). Chrondral explants were harvested and exposed to 1 of 4 different irrigation fluids for 1 hour: Ringer's solution, normal saline (0.9% NaCl), 1.5% glycine, or 5% mannitol. M199 culture medium was used as a positive control, and 0.5% bupivicaine, previously shown to be harmful to articular cartilage, as a negative control. After exposure, explants were incubated with radiolabeled sulfate ((35)S0(4)), and uptake was measured after 16 hours as an indicator of proteoglycan synthesis.

RESULTS

(35)S0(4) uptake was inhibited 10% by Ringer's solution (P = .3), 24% by 1.5% glycine (P = .08), 31% by 5% mannitol (P = .03), 35% by normal saline (P = .04), and 90% by 0.5% bupivacaine (P < .001), compared with the M199 control. Comparisons of the different solutions showed that all solutions were less inhibitory than 0.5% bupivacaine (P < .001). The only significant difference was that between normal saline and Ringer's solution (P = .03).

CONCLUSIONS

In an in vitro model of human articular cartilage, Ringer's solution had the least effect on cartilage metabolism, and normal saline caused the greatest inhibition of cartilage metabolism.

CLINICAL RELEVANCE

Normal saline, the most commonly used irrigation fluid, may have an inhibitory effect on proteoglycan metabolism in articular cartilage. Additional studies are required to assess the potential damage to cartilage from normal saline in the clinical setting.

Effect of a solution of hyaluronic acid-chondroitin sulfate-N-acetyl glucosamine on the repair response of cartilage to single-impact load damage

OBJECTIVE

To investigate effects of 1% hyaluronic acid-chondroitin sulfate-N-acetyl glucosamine (HCNAG) on the damage repair response in equine articular cartilage.

SAMPLE

Articular cartilage from 9 clinically normal adult horses.

PROCEDURES

Full-thickness cartilage disks were harvested from the third metacarpal bone. Cartilage was single-impact loaded (SIL) with 0.175 J at 0.7 m/s and cultured in DMEM plus 1 % (vol/vol) HCNAG or fibroblastic growth factor (FGF)-2 (50 ng/mL). Histologic and immunohistochemical techniques were used to identify tissue architecture and apoptotic cells and to immunolocalize type I and II collagen and proliferating nuclear cell antigen (PCNA).

RESULTS

Type II collagen immunoreactivity increased in SIL cartilage, compared with control samples. At days 14 and 28 (day 0 = initiation of culture), control samples had significantly fewer repair cells than did other treatment groups. In control samples and SIL + HCNAG, there was a significant decrease in apoptotic cell number, compared with results for SIL and SIL + FGF-2 samples. At days 14 and 28, there was a significant increase in chondrocytes stained positive for PCNA in the control samples.

CONCLUSIONS AND CLINICAL RELEVANCE

1% HCNAG significantly affected apoptotic and repair cell numbers in an SIL damage-repair technique in adult equine articular cartilage. However, HCNAG had no effect on the number of PCNA-positive chondrocytes or on type II collagen immunohistochemical results. The inclusion of 1% HCNAG in lavage solutions administered after arthroscopy may be beneficial to cartilage health by increasing the number of repair cells and decreasing the number of apoptotic cells.

Hyperosmolarity protects chondrocytes from mechanical injury in human articular cartilage

The aim of this study was to determine whether exposure of human articular cartilage to hyperosmotic saline (0.9%, 600 mOsm) reduces in situ chondrocyte death following a standardised mechanical injury produced by a scalpel cut compared with the same assault and exposure to normal saline (0.9%, 285 mOsm). Human cartilage explants were exposed to normal (control) and hyperosmotic 0.9% saline solutions for five minutes before the mechanical injury to allow in situ chondrocytes to respond to the altered osmotic environment, and incubated for a further 2.5 hours in the same solutions following the mechanical injury.

Using confocal laser scanning microscopy, we identified a sixfold (p = 0.04) decrease in chondrocyte death following mechanical injury in the superficial zone of human articular cartilage exposed to hyperosmotic saline compared with normal saline.

These data suggest that increasing the osmolarity of joint irrigation solutions used during open and arthroscopic articular surgery may reduce chondrocyte death from surgical injury and could promote integrative cartilage repair.