Articular Cartilage Pathology Research Articles

Type VI Collagen Regulates Pericellular Matrix Properties, Chondrocyte Swelling, and Mechanotransduction in Mouse Articular Cartilage.

Mechanical factors play a critical role in the physiology and pathology of articular cartilage, although the mechanisms of mechanical signal transduction are not fully understood. We undertook this study to test the hypothesis that type VI collagen is necessary for mechanotransduction in articular cartilage by determining the effects of type VI collagen knockout on the activation of the mechano-osmosensitive, calcium-permeable channel TRPV4 (transient receptor potential vanilloid channel 4) as well as on osmotically induced chondrocyte swelling and pericellular matrix (PCM) mechanical properties. Confocal laser scanning microscopy was used to image TRPV4-mediated calcium signaling and osmotically induced cell swelling in intact femora from 2- and 9-month-old wild-type (WT) and type VI collagen-deficient (Col6a1(-/-)) mice. Immunofluorescence-guided atomic force microscopy was used to map PCM mechanical properties based on the presence of perlecan. Hypo-osmotic stress-induced TRPV4-mediated calcium signaling was increased in Col6a1(-/-) mice relative to WT controls at 2 months. Col6a1(-/-) mice exhibited significantly increased osmotically induced cell swelling and decreased PCM moduli relative to WT controls at both ages. In contrast to our original hypothesis, type VI collagen was not required for TRPV4-mediated Ca(2+) signaling; however, knockout of type VI collagen altered the mechanical properties of the PCM, which in turn increased the extent of cell swelling and osmotically induced TRPV4 signaling in an age-dependent manner. These findings emphasize the role of the PCM as a transducer of mechanical and physicochemical signals, and they suggest that alterations in PCM properties, as may occur with aging or osteoarthritis, can influence mechanotransduction via TRPV4 or other ion channels.

Meniscal and Articular Cartilage Predictors of Clinical Outcome following Revision ACL Reconstruction

Objectives:Revision ACL reconstruction has been documented to have worse outcomes compared with primary ACL reconstructions. The reasons why remain unknown. The purpose of this study was to determine if both the prevalence and/or degree of meniscal and chondral damage noted at the time of ACL revision reconstruction predicts activity level, sports function, and OA symptoms at two year follow-up.Methods:Revision ACL reconstruction patients were identified and prospectively enrolled between 2006 and 2011. Data collected included baseline demographics, surgical technique and pathology, and a series of validated patient reported outcome instruments (IKDC, KOOS, WOMAC, and Marx activity rating score). Patients were followed up for 2 years, and asked to complete the identical set of outcome instruments. Regression analysis was used to control for age, gender, BMI, smoking status, activity level, baseline outcome scores, revision number, time since last ACLR, previous and current meniscal and articular cartilage pathology, in order to assess the meniscal and AC pathology risk factors for clinical outcomes 2 years after revision ACL reconstruction.Results:1205 patients met the inclusion criteria and were successfully enrolled. 697 (58%) were males, with a median cohort age of 26 years. The median time since their last ACL reconstruction was 3.4 years. Surgeons noted previous pathology in the medial meniscus (39%), lateral meniscus (20%), and articular surfaces (12%) at the time of revision surgery. Surgeons reported current pathology in the medial meniscus (45%), lateral meniscus (37%), MFC (43%), LFC (29%), MTP (11%), LTP (17%), patella (30%), and trochlea (20%). At 2 years, follow-up was obtained on 82% (989/1205). Previous meniscal pathology (both medial and lateral), as well as current AC pathology (in the MFC, LFC, MTP, LTP, and trochlea) were found to be significant drivers of poorer outcomes at 2 years (Table 1). The most consistent cartilage-related factors driving outcome in revision patients were previous lateral meniscus pathology and current trochlea AC pathology. Having a previous excision on the lateral meniscus resulted in significantly poorer outcomes on the IKDC (odds ratio=1.69; 95% CI=1.16-2.44; p=0.005), all KOOS subscales (OR range=1.54-2.08; 95% CI=1.04-3.03; p<0.029), and all WOMAC subscales (OR=1.56; 95% CI=1.06-2.27; p=0.02). Having a current Grade 3-4 AC chondrosis of the trochlea resulted in significantly poorer outcomes in the IKDC (OR=1.89; 95% CI=1.25-2.94; p-0.003), 4 of 5 KOOS subscales (OR range = 1.64-2.70; 95% CI=1.09-4.17; p<0.02), and 2 of 3 WOMAC subscales (OR range = 1.61-2.70; 95% CI=1.04-4.17; p<0.03). Lower baseline outcome scores, lower baseline activity level, and shorter time since the patient’s last ACL reconstruction all significantly increased the odds of reporting poorer clinical outcomes at 2 years. Meniscal and AC pathology was not found to be a significant risk factor for 2 year activity levels. Interestingly, previous AC pathology and current meniscal pathology were not found to be significant risk factors for 2 year outcomes in this revision cohort.Conclusion:Having a previous meniscal excision, as well as grade 3-4 chondral damage noted at the time of ACL revision reconstruction results in decreased sports outcome scores and worse WOMAC scores at two years following revision surgery. However, incidence of meniscal and AC pathology was not found to be a predictor of a patient’s activity level at 2 years.

Adult mice lacking the type 2 iodothyronine deiodinase have increased subchondral bone but normal articular cartilage.

Although osteoarthritis (OA) is the commonest joint disorder and has a rising prevalence as the population ages, no drugs are available that prevent or delay the onset and progression of disease. Recent studies identified the DIO2 gene encoding type 2 deiodinase (D2) as a susceptibility locus for OA, and further data suggest deiodinase-regulated local availability of triiodothyronine (T3) in the joint plays an important role in cartilage maintenance and repair. To investigate the hypothesis that reduced tissue T3 availability protects joints from development of OA, the joint phenotypes of adult mice lacking D2 (D2KO) or lacking both D1 and D2 (D1D2KO), the only enzymes that catalyze conversion of the prohormone thyroxine to active T3, were determined. Knee joints were prepared from male 16-week-old adult wild type (WT; n=9), D2KO (n=5), and D1D2KO (n=3) mice. Articular cartilage pathology was scored using the Osteoarthritis Research Society International (OARSI) histopathology scale for murine OA to determine the severity and extent of disease. Digital X-ray microradiography was used to determine the area and mineral content of subchondral bone immediately beneath the articular cartilage surface. There were no differences in maximum and standardized OA scores, cartilage erosion indices, or articular cartilage cellularity among WT, D2KO, and D1D2KO mice. Subchondral bone area did not differ among genotypes, but mineral content was markedly increased in both D2KO and D1D2KO mice compared to WT. Although adult D2KO mice have normal articular cartilage and no other features of spontaneous joint damage, they exhibit increased subchondral bone mineral content.

Altered swelling and ion fluxes in articular cartilage as a biomarker in osteoarthritis and joint immobilization: a computational analysis.

In healthy cartilage, mechano-electrochemical phenomena act together to maintain tissue homeostasis. Osteoarthritis (OA) and degenerative diseases disrupt this biological equilibrium by causing structural deterioration and subsequent dysfunction of the tissue. Swelling and ion flux alteration as well as abnormal ion distribution are proposed as primary indicators of tissue degradation. In this paper, we present an extension of a previous three-dimensional computational model of the cartilage behaviour developed by the authors to simulate the contribution of the main tissue components in its behaviour. The model considers the mechano-electrochemical events as concurrent phenomena in a three-dimensional environment. This model has been extended here to include the effect of repulsion of negative charges attached to proteoglycans. Moreover, we have studied the fluctuation of these charges owning to proteoglycan variations in healthy and pathological articular cartilage. In this sense, standard patterns of healthy and degraded tissue behaviour can be obtained which could be a helpful diagnostic tool. By introducing measured properties of unhealthy cartilage into the computational model, the severity of tissue degeneration can be predicted avoiding complex tissue extraction and subsequent in vitro analysis. In this work, the model has been applied to monitor and analyse cartilage behaviour at different stages of OA and in both short (four, six and eight weeks) and long-term (11 weeks) fully immobilized joints. Simulation results showed marked differences in the corresponding swelling phenomena, in outgoing cation fluxes and in cation distributions. Furthermore, long-term immobilized patients display similar swelling as well as fluxes and distribution of cations to patients in the early stages of OA, thus, preventive treatments are highly recommended to avoid tissue deterioration.

Mesenchymal stem cells: A new diagnostic tool?

Mesenchymal stem cells (MSCs) are progenitor cells capable of self-renewal that can differentiate in multiple tissues and, under specific and standardized culture conditions, expand in vitro with little phenotypic alterations. In recent years, preclinical and clinical studies have focused on MSC analysis and understanding the potential use of these cells as a therapy in a wide range of pathologies, and many applications have been tested. Clinical trials using MSCs have been performed (e.g., for cardiac events, stroke, multiple sclerosis, blood diseases, auto-immune disorders, ischemia, and articular cartilage and bone pathologies), and for many genetic diseases, these cells are considered an important resource. Considering of the biology of MSCs, these cells may also be useful tools for understanding the physiopathology of different diseases, and they can be used to develop specific biomarkers for a broad range of diseases. In this editorial, we discuss the literature related to the use of MSCs for diagnostic applications and we suggest new technologies to improve their employment.

Spatial mapping of proteoglycan content in articular cartilage using near-infrared (NIR) spectroscopy.

Diagnosis of articular cartilage pathology in the early disease stages using current clinical diagnostic imaging modalities is challenging, particularly because there is often no visible change in the tissue surface and matrix content, such as proteoglycans (PG). In this study, we propose the use of near infrared (NIR) spectroscopy to spatially map PG content in articular cartilage. The relationship between NIR spectra and reference data (PG content) obtained from histology of normal and artificially induced PG-depleted cartilage samples was investigated using principal component (PC) and partial least squares (PLS) regression analyses. Significant correlation was obtained between both data (R(2) = 91.40%, p<0.0001). The resulting correlation was used to predict PG content from spectra acquired from whole joint sample, this was then employed to spatially map this component of cartilage across the intact sample. We conclude that NIR spectroscopy is a feasible tool for evaluating cartilage contents and mapping their distribution across mammalian joint.

Mesenchymal stem-cell potential in cartilage repair: an update.

Articular cartilage damage and subsequent degeneration are a frequent occurrence in synovial joints. Treatment of these lesions is a challenge because this tissue is incapable of quality repair and/or regeneration to its native state. Non-operative treatments endeavour to control symptoms and include anti-inflammatory medications, viscosupplementation, bracing, orthotics and activity modification. Classical surgical techniques for articular cartilage lesions are frequently insufficient in restoring normal anatomy and function and in many cases, it has not been possible to achieve the desired results. Consequently, researchers and clinicians are focusing on alternative methods for cartilage preservation and repair. Recently, cell-based therapy has become a key focus of tissue engineering research to achieve functional replacement of articular cartilage. The present manuscript is a brief review of stem cells and their potential in the treatment of early OA (i.e. articular cartilage pathology) and recent progress in the field.

Characterization of Meniscal Pathology Using Molecular and Proteomic Analyses.

The meniscus is a complex tissue and is integral to knee joint health and function. Although the meniscus has been studied for years, a relatively large amount of basic science data on meniscal health and disease are unavailable. Genomic and proteomic analyses of meniscal pathology could greatly improve our understanding of etiopathogenesis and the progression of meniscal disease, yet these analyses are lacking in the current literature. Therefore, the objective of this study was to use microarray and proteomic analyses to compare aged-normal and pathologic meniscal tissues. Meniscal tissue was collected from the knees of five patient groups (n = 3/group). Cohorts included patients undergoing meniscectomy with or without articular cartilage pathology, patients undergoing total knee arthroplasty with mild or moderate-severe osteoarthritis, and aged-normal controls from organ donors. Tissue sections were collected from the white/white and white/red zones of posterior medial menisci. Expression levels were compared between pathologic and control menisci to identify genes of interest (at least a ×1.5 fold change in expression levels between two or more groups) using microarray analysis. Proteomics analysis was performed using mass spectrometry to identify proteins of interest (those with possible trends identified between the aged-normal and pathologic groups). The microarray identified 157 genes of interest. Genes were categorized into the following subgroups: (1) synthesis, (2) vascularity, (3) degradation and antidegradation, and (4) signaling pathways. Mass spectrometry identified 173 proteins of interest. Proteins were further divided into the following categories: (1) extracellular matrix (ECM) proteins; (2) proteins associated with vascularity; (3) degradation and antidegradation proteins; (4) cytoskeleton proteins; (5) glycolysis pathway proteins; and (6) signaling proteins. These data provide novel molecular and biochemical information for the investigation of meniscal pathology. Further evaluation of these disease indicators will help researchers develop algorithms for diagnostic, therapeutic, and prognostic strategies related to meniscal disorders.

Cartilage Repair With or Without Meniscal Transplantation and Osteotomy for Lateral Compartment Chondral Defects of the Knee: Case Series With Minimum 2-Year Follow-up.

Background:Treatment decision making for chondral defects in the knee is multifactorial. Articular cartilage pathology, malalignment, and meniscal deficiency must all be addressed to optimize surgical outcomes.Purpose:To determine whether significant clinical improvements in validated clinical outcome scores are observed at minimum 2-year follow-up after articular cartilage repair of focal articular cartilage defects of the lateral compartment of the knee with or without concurrent distal femoral osteotomy and lateral meniscus transplant.Study Design:Case series; Level of evidence, 4.Methods:Symptomatic adults who underwent surgical treatment (microfracture, autologous chondrocyte implantation [ACI], osteochondral autograft or allograft) of full-thickness lateral compartment chondral defects of the knee with or without a postmeniscectomy compartment or valgus malalignment by a single surgeon with minimum 2-year follow-up were analyzed. Validated patient-reported and surgeon-measured outcomes were collected pre- and postsurgery. Pre- and postoperative outcomes were compared via Student t tests.Results:Thirty-five subjects (mean age, 29.6 ± 10.5 years) were analyzed. Patients had been symptomatic for 2.51 ± 3.52 years prior to surgery and had undergone 2.11 ± 1.18 surgeries prior to study enrollment, with a mean duration of follow-up of 3.65 ± 1.71 years. The mean defect size was 4.42 ± 2.06 cm2. Surgeries included ACI (n = 18), osteochondral allograft (n = 14), osteochondral autograft (n = 2), and microfracture (n = 1). There were 18 subjects who underwent concomitant surgery (14 lateral meniscus transplant, 3 distal femoral osteotomy, and 1 combined). Statistically significant (P < .05) and clinically meaningful improvements were observed at final follow-up in Lysholm, subjective International Knee Documentation Committee (IKDS), Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales, Short Form–12 (SF-12) scores, and patient satisfaction. At follow-up, patients undergoing isolated articular cartilage surgery had a significantly higher KOOS quality of life subscore than did those undergoing articular cartilage surgery and lateral meniscus transplant (P = .039). Otherwise, there were no significant postoperative differences between the isolated and combined surgery groups in any outcome score. Five patients underwent 6 reoperations (1 revision osteochondral allograft, 5 chondroplasties). No patient was converted to knee arthroplasty.Conclusion:In patients with lateral compartment focal chondral defects with or without lateral meniscal deficiency and valgus malalignment, surgical cartilage repair and correction of concomitant pathology can significantly improve clinical outcomes at 2-year follow-up with no significant differences between isolated and combined surgery and a low rate of complications and reoperations.

Cartilage Repair with or without Meniscal Transplantation and Osteotomy for Lateral Compartment Chondral Defects

Background:Treatment decision making for chondral defects in the knee is multifactorial. Articular cartilage pathology, malalignment, and meniscal deficiency must all be addressed to optimize surgical outcomes.Purpose:To determine whether significant clinical improvements in validated clinical outcome scores are observed at minimum 2-year follow-up after articular cartilage repair of focal articular cartilage defects of the lateral compartment of the knee with or without concurrent distal femoral osteotomy and lateral meniscus transplant.Study Design:Case series; Level of evidence, 4.Methods:Symptomatic adults who underwent surgical treatment (microfracture, autologous chondrocyte implantation [ACI], osteochondral autograft or allograft) of full-thickness lateral compartment chondral defects of the knee with or without a postmeniscectomy compartment or valgus malalignment by a single surgeon with minimum 2-year follow-up were analyzed. Validated patient-reported and surgeon-measured outcomes were collecte...

The role of ank in catabolic events of articular chondrocytes

s / Osteoarthritis and Cartilage 22 (2014) S57–S489 S133 210 THE ROLE OF ANK IN CATABOLIC EVENTS OF ARTICULAR CHONDROCYTES T. Kirsch y, T. Minashima y, K. Campbell y, S. Hadley z, Y. Zhang x. yNYU Sch. of Med., New York, NY; zBrigham Women’s Hosp., Harvard Med. Sch., Boston, MA, USA; xCtr. for Joint Surgery, Southwest Hosp., Third Military Med. Univ., Chong Qing, China Purpose: The progressive ankylosis protein (ANK) is a transmembrane protein that transports intracellular pyrophosphate (PPi) to the extracellular milieu. Lack of functional ANK in ank/ank mice or ank knockout mice leads to pathological mineralization of articular cartilage, ligaments, menisci and tendons resulting in arthritic changes because of the reduced amounts of extracellular PPi, a main mineralization inhibitor. We and others, however, have shown that ANK is expressed at low levels in healthy articular cartilage, and ANK expression levels drastically increase during osteoarthritis (OA) initiation and progression. These findings raise the possibility that ANK plays more complex and unknown functions in articular cartilage and OA pathology than only preventing basic calcium crystal formation. Therefore, the purpose of this study was to determine the role of ANK in catabolic events of articular chondrocytes. Methods: The interactions of ANK with Myb-binding protein 1a (MYBBP1a) and sphingosine kinase 1 (SPHK1)were identified using yeast two-hybrid screening and co-immunoprecipitation. To determine the role of these interactions in catabolic events of articular chondrocytes, ank/ank and wild type (WT) mouse chondrocytes or femoral heads were treated with interleukin-1beta (IL-1b) in the absence or presence of the SPHK inhibitor, SKI-II. Catabolic marker mRNA levels were analyzed by real time PCR; proteoglycan loss using safranin O staining and MMP-13 immunostaining were determined in femoral head explants; NF-kB activity was determined by transfecting chondrocytes with a NF-kBspecific luciferase reporter and analyzing nuclear translocation of p65 by immunoblotting; MYBBP1a nuclear or cytoplasmic amounts were determined by immunohistochemistry and immunoblotting. Results: Yeast two-hybrid screening and co-immunoprecipitation experiments revealed that the N-terminal region of ANK interacts with SPHK1, whereas the C-terminal region interacts withMYBBP1a. MYBBP1a isa cytoplasmicprotein that canshuttle into thenucleuswhere it represses NF-kB transcriptional activity. Consequently, the loss of ANK/MYBBP1a interactions resulted in increased MYBBP1a nuclear amounts and decreasedNF-kB activity in IL-1b-treated ank/ank chondrocytes compared to IL-1b-treated WT cells. The loss of ANK/SPHK1 interaction resulted in decreased SPHK1 activity in IL-1b-treated ank/ank chondrocytes compared to IL-1b-treated WT cells. Activation of NF-kB-dependent transcriptional activity by IL-1b involves translocation of NF-kB family members, in particular p65 (RelA) and p50, from the cytoplasm to the nucleus. The increase of the nuclear p65 amount and the decrease of the cytoplasmic p65 amount in IL-1b-treated ank/ank chondrocytes were markedly reduced compared to IL-1b-treatedWTcells. The SPHK inhibitor, SKI-II reduced the amount of nuclear p65 and increased the amount of cytoplasmicp65 in IL-1b-treatedWTchondrocytes butnot in IL-1b-treated ank/ank chondrocytes. Transfection with ank expression vector reduced nuclearMYBBP1a amounts and fully restored SPHK andNF-kB activities in IL-1b-treated ank/ank chondrocytes, whereas transfection with P5L mutant ank that doesnot interactwith SPHK1or F376del ank thatdoes not interact with MYBBP1a increased SPHK activity or reduced nuclear MYBBP1a, respectively, and consequently either transfection with P5L or F376del ank only partially restored NF-kB activity. Finally, lack of ANK/ MYBBP1a and SPHK1 interactions in ank/ank chondrocytes resulted in decreased catabolic marker mRNA levels, proteoglycan loss, and MMP-13 immunostaining in IL-1b-treated articular chondrocytes or femoral heads. Conclusion: This study shows that ANK interacts via the N-terminal and C-terminal cytoplasmic regions with SPHK1 and MYBBP1a, respectively. The ANK/MYBBP1a interaction results in the inhibition of the nuclear translocation of MYBBP1a. Nuclear MYBBP1a acts as a corepressor of NF-kB transcriptional activity. The ANK/SPHK1 interaction is a major regulator of SPHK1 activity. Both interactions stimulate NF-kB activity and ultimately catabolic events in IL-1b-treated articular chondrocytes. Since IL-1b and NF-kB play major roles in OA pathogenesis, our findings suggest that increased ANK expression in OA cartilage may be a major contributor to cartilage destruction. Future experiments are needed to fully understand the mechanisms of the interactions between ANK, MYBBP1a and SPHK1 in OA pathology and develop strategies to interfere with these interactions as a potential novel therapy for the treatment of OA. 211 OSX-CRE DIRECTED ABLATION OF SITE-1 PROTEASE IN MICE RESULTS IN KYPHOSIS AND SCOLIOSIS D. Patra, E. DeLassus, L.J. Sandell.Washington Univ. Sch. of Med., St. Louis,

Pathology of Articular Cartilage and Synovial Membrane From Elbow Joints With and Without Degenerative Joint Disease in Domestic Cats

The elbow joint is one of the feline appendicular joints most commonly and severely affected by degenerative joint disease. The macroscopic and histopathological lesions of the elbow joints of 30 adult cats were evaluated immediately after euthanasia. Macroscopic evidence of degenerative joint disease was found in 22 of 30 cats (39 elbow joints) (73.33% cats; 65% elbow joints), and macroscopic cartilage erosion ranged from mild fibrillation to complete ulceration of the hyaline cartilage with exposure of the subchondral bone. Distribution of the lesions in the cartilage indicated the presence of medial compartment joint disease (most severe lesions located in the medial coronoid process of the ulna and medial humeral epicondyle). Synovitis scores were mild overall and correlated only weakly with macroscopic cartilage damage. Intra-articular osteochondral fragments either free or attached to the synovium were found in 10 joints. Macroscopic or histologic evidence of a fragmented coronoid process was not found even in those cases with intra-articular osteochondral fragments. Lesions observed in these animals are most consistent with synovial osteochondromatosis secondary to degenerative joint disease. The pathogenesis for the medial compartmentalization of these lesions has not been established, but a fragmented medial coronoid process or osteochondritis dissecans does not appear to play a role.

Platelet-Rich Plasma in the Management of Articular Cartilage Pathology

Using systematic review methodology, we endeavored to answer the following questions concerning the treatment of osteochondral pathology: (1) what pathologies have been treated in vivo with the use of platelet-rich plasma (PRP); (2) what methods of PRP preparation and delivery have been reported; (3) what assessment tools and comparison group have been used to assess its effectiveness; and (4) what are the clinical outcomes of its use. A systematic literature search was performed of the OVID, EMBASE, and Evidence Based Medicine Reviews databases to identify all studies published up to October 2012 that assessed clinical outcomes of the use of PRP for the treatment of chondral and osteochondral pathology, excluding those including concomitant management of acute fractures or ligament reconstruction. The included studies were reviewed and the following data were extracted and tabulated: study authors' year and journal, study design and level of evidence, pathology treated, methods of PRP preparation and delivery, and clinical outcome scores. Ten studies were included in the final analysis. The majority of studies assessed the use of PRP in the treatment of degenerative osteoarthritis of the knee or hip (representing 570 of a total of 662 joints). The majority of patients were treated with intra-articular injections, whereas 2 studies used PRP as an adjunct to surgical treatment. Significant improvements in joint-specific clinical scores (7 of 8 studies), general health scores (4 of 4 studies), and pain scores (4 of 6 studies) compared with baseline were reported up to 6-month follow-up, but few studies provided longer-term data. No studies reported worse scores compared with baseline at final follow-up. Three of 4 comparative studies reported significantly better clinical and/or pain scores when compared with hyaluronic acid injections at similar follow-up times. Currently, there is a paucity of data supporting the use of PRP for the management of focal traumatic osteochondral defects. There is limited evidence suggesting short-term clinical benefits with the use of PRP for symptomatic osteoarthritis of the knee, but the studies published to date are of poor quality and at high risk for bias. Further high-quality comparative studies with longer follow-up are needed to ascertain whether PRP is beneficial, either alone or as an adjunct to surgical procedures, in the management of articular cartilage pathology.

Basic Knee Arthroscopy Part 3: Diagnostic Arthroscopy

Knee arthroscopy is an important diagnostic and therapeutic tool in the management of disorders of the knee. In a series of 4 articles, the basics of knee arthroscopy are reviewed. In this article (part 3), step-by-step diagnostic arthroscopy is reviewed. Diagnostic arthroscopy is a crucial skill for diagnosing intra-articular disorders of the knee including meniscal, synovial, ligamentous, and articular cartilage pathology. Mastery of the basic diagnostic arthroscopy is a critical tool for orthopaedic surgeons treating disorders of the knee.

TGFβ1 increases oxidative stress in human osteoarthritis articular chondrocytes through mechanisms involving NOX4

TGFβ1 increases oxidative stress in human osteoarthritis articular chondrocytes through mechanisms involving NOX4

The relationship between synovial fluid ARGS, cytokines, MMPs & TIMPs following acute ACL injury

s / Osteoarthritis and Cartilage 21 (2013) S63–S312 S75 active ADAMTS-4 where surface fibrillation and clustered chondrocytes were observed and lost when there was no proteoglycan observed. MMP-9 staining was strong throughout the OA sections when pronounced OA characteristics, such as fibrillation, erosion and hypertrophy, were present Conclusions: Better understanding on the dynamics of proteolytical activity profiles in OA cartilage may aid in improved insight to joint pathology. This should lead to enhanced targeting of novel intervention for OA. 123 THE RELATIONSHIP BETWEEN SYNOVIAL FLUID ARGS, CYTOKINES, MMPS & TIMPS FOLLOWING ACUTE ACL INJURY T.W. Tourville y, R.J. Johnson y, J.R. Slauterbeck y, S. Naud y, L.S. Lohmander z,x, A. Struglics z, B.D. Beynnon y. yUniv. of Vermont Coll. of Med., Burlington, VT, USA; z Lund Univ., Dept. of Orthopaedics, Clinical Sci. Lund, Lund, Sweden; xRes. Unit for Musculoskeletal Function and Physiotherapy, Inst. for Sports and Clinical Biomechanics, Univ. of Southern Denmark, Denmark, Sweden Purpose: Injury to the Anterior Cruciate Ligament (ACL) results in a high incidence of Post-Traumatic Osteoarthritis (PTOA). Limited information is available regarding the role of inflammatory mediators in PTOA, especially during the onset and earliest stages of the disease process. Recent investigations have provided evidence that a biochemical response occurs very soon after acute knee trauma, and aggrecan degradation (evidenced by elevated levels of synovial fluid (SF) aggrecanase generated N-terminal ARGS) is associated with inflammatory activity during the initial few weeks following acute ACL rupture. It is not known, however, if this process persists for a longer time interval following trauma; if ARGS concentrations are associated with additional cytokines not previously described; or how ARGS concentrations relate to levels of matrix metalloproteases (MMPs) or tissue inhibitors of metalloproteases (TIMPs) found in the synovial fluid following ACL disruption. Consequently, the purpose of this study was to evaluate relationships between SF ARGS levels and an array of cytokines, MMPs and TIMPs within the 6 months following acute ACL rupture. Methods: Synovial fluid samples from 67 ACL-injured patients (29 women) were used for analysis in this exploratory, cross sectional study. Entry criteria included: Age at the time of enrollment 1⁄4 1455yrs; BMI 1⁄4 18.5-30, Tegner score > 4; no relevant knee pathologies other than the index ACL injury; normal lower extremity alignment; and relatively minor articular cartilage and meniscal pathologies. All samples were obtained within 6 months of injury (18-155 days) via non-lavage arthrocentesis immediately prior to surgical ACL reconstruction. SF samples were analyzed for ARGS concentration via electrochemiluminescence immunoassay. Concentrations of 42 different cytokines were evaluated using commercially available Luminex-based multiplex analysis kits (42-Plex), as were 8 MMPs (panels 1 & 2), and 4 TIMPs (panel 1) (Millipore, Billerica, MA). Relationships between ARGS concentrations and individual analyte concentrations as well as MMP/TIMP ratios were evaluated statistically with partial Spearman Partial Correlation tests (rs), while adjusting for age, sex, and time since injury. This analysis technique was chosen because it is not strongly influenced by normality of data or “outliers.” Results: Statistically significant relationships were found between ARGS concentrations and FGF-2 (rs 1⁄4 -0.27, p 1⁄4 0.03) and TIMP-3 (rs 1⁄4 0.33, p 1⁄4 0.01). Although not statistically significant, FLT-3L, IP-10, and TIMP-1 had correlations greater than 0.20 (absolute values), trending toward significant correlations (Table 1). All other analytes tested received r-values less than 0.2 and were not significant.

Raman spectroscopy investigation of load-assisted microstructural alterations in human knee cartilage: Preliminary study into diagnostic potential for osteoarthritis

A preliminary investigation into the diagnostic potential of Raman spectroscopy for assessing pathological articular cartilage was conducted. Five arthritic human tibial cartilages retrieved after total knee arthroplasty were examined using near-infrared (NIR) Raman spectroscopy excited with 647.1nm lines of a Kr-ion laser. A “healthy” cartilage obtained from cadaver donor was also examined as a control sample. Degradation severity was first visually classified into five grades (Grade 0–VI) on the surface of both medial and lateral zones in each tibial plateau, according to the Collins scale. Raman spectra were then collected from selected zones with different damage severity. A systematic increase in relative intensity ratio between the Raman bands located at 1241 and 1269cm−1 (amide III doublet) was observed with increasing degradation grades, which could be related to structural changes under loading in type II collagen. This finding suggests that the present spectroscopic approach might be useful for recognizing and quantitatively assessing the degree of osteoarthritis (OA) in its early manifestation stage.

Are Articular Cartilage Lesions and Meniscus Tears Predictive of IKDC, KOOS, and Marx Activity Level Outcomes after ACL Reconstruction? A 6-Year MOON Cohort Study

Objectives:Identifying risk factors for inferior outcomes after ACL reconstruction (ACLR) is important for prognosis and future treatment. Study goal: analyze a sufficiently large enough cohort to evaluate whether articular cartilage and meniscal variables are predictive of three validated sports outcome instruments. We hypothesized that articular cartilage lesions and meniscus tears/treatment would be predictors of IKDC, KOOS (all 5 subscales), and Marx Activity Level at 6 years after ACLR.Methods:From 2002-2004, 1411 ACLR subjects were prospectively enrolled and followed longitudinally with the IKDC, KOOS, and Marx completed at entry, 2 and 6 years. A logistic multivariable model consisted of patient demographics, surgical technique variables, and articular cartilage injuries and meniscus tears/treatment for determining predictors (risk factors) of IKDC, KOOS, and Marx at 6 years.Results:We completed a minimum follow-up on 93% (1307/1411) of our cohort at 6 years. Baseline results: 56% male, median age 23 years, 75% with non-contact injury mechanism, articular cartilage pathology (MFC-25%, LFC-20%, MTP-6%, LTP-12%, patella-20%, and trochlear-9%), and meniscal pathology (medial-38%, lateral-46%). Both articular cartilage lesions and meniscal tears significantly predicted 6 year outcomes on IKDC and KOOS (Table 1). Grade 3 or 4 articular cartilage lesions (excluding patella) significantly reduced IKDC and KOOS scores at 6 years. Figure 1 focuses on IKDC and demonstrates worse outcomeswith chondral injuries on the MFC, MTP, and LFC. Likewise, KOOS was negatively affected by cartilage injury. The sole significant predictor of reduced Marx activity was the presence of a grade 4 lesion on the MFC. Lateral meniscus repairs did not correlate with inferior results, but medial meniscus repairs predicted worse IKDC and KOOS scores. Lateral meniscus tears left alone significantly improved prognosis. Small partial meniscectomies (<33%) on medial meniscus fared worse, but conversely, larger excisions on lateral meniscus (>50%) improved prognosis. Analogous to previous studies, other significant predictors of worse outcome scores were lower baseline scores, higher BMI, lower education level, smoking, and revisions.Conclusion:Both articular cartilage injury and meniscal tears/treatment at the time of ACLR were significant predictors of both IKDC and KOOS scores at 6 year follow-up. Similarly, having a grade 4 MFC lesion significantly reduced a patient’s Marx activity level score at 6 years.

Long term followup of fresh osteochondral allografting of the femoral condyle

Long term followup of fresh osteochondral allografting of the femoral condyle

Engineering endostatin-expressing cartilaginous constructs using injectable biopolymer hydrogels

The release of an anti-angiogenic agent, such as type XVIII/endostatin, from an implantable scaffold may be of benefit in the repair of articular cartilage. The objectives of this study are to develop an injectable mesenchymal stem cell (MSC)-incorporating collagen-based hydrogel capable of undergoing covalent cross-linking in vivo and overexpressing endostatin using nonviral transfection, and to investigate methods for the retention of the endostatin protein within the scaffolds. The effects of different cross-linking agents (genipin, transglutaminase-2, and microbial transglutaminase) and different binding molecules for endostatin retention (heparin, heparan sulfate, and chondroitin sulfate) are evaluated. Cartilaginous constructs that overexpress endostatin for 3weeks are successfully engineered. Most of the endostatin is released into the surrounding media and is not retained within the constructs. The presence of two common basement membrane molecules, laminin and type IV collagen, which have been reported in developing and mature articular cartilage and are generally associated with type XVIII collagen in vivo, is also observed in the engineered cartilaginous constructs. Endostatin-producing cartilaginous constructs can be formulated by growing nonvirally transfected mesenchymal stem cells in collagen gels covalently cross-linked using genipin, transglutaminase-2, and microbial transglutaminase. These constructs warrant further investigation for cartilage repair procedures. The novel finding of laminin and type IV collagen in the engineered cartilage constructs may be of importance for future work toward understanding the role of basement membrane molecules in chondrogenesis and in the physiology and pathology of articular cartilage.