A family history of knee joint replacement increases the progression of knee radiographic osteoarthritis and medial tibial cartilage volume loss over 10 years

Comparative Analysis of Short-Term and Long-Term Clinical Efficacy of Mesenchymal Stem Cells from Different Sources in Knee Osteoarthritis: A Network Meta-Analysis

Background

Joint articular injection of mesenchymal stem cells (MSCs) has emerged as a novel treatment approach for osteoarthritis (OA). However, the effectiveness of MSCs derived from different sources in treating OA patients remains unclear. Therefore, this study aimed to explore the differences between the effectiveness and safety of different sources of MSCs.

Materials and Methods

For inclusion consideration, we searched trial registries and published databases, including PubMed, Cochrane Library, Embase, and Web of Science databases. Revman (V5.3), STATA (V16.0), and R (V4.0) were utilized for conducting data analysis, while the Cochrane Risk of Bias Tool was employed for assessing the quality of the studies. We derived outcome measures at 6 and 12 months based on the duration of study follow-up, including visual analog scale (VAS) score, WOMAC score, WOMAC pain, WOMAC Functional Limitation, and WOMAC stiffness. The evaluation time for short-term effectiveness is set at 6 months, while 12 months is utilized as the longest follow-up time for most studies to assess long-term effectiveness.

Results

The evaluation of literature quality showed that the included studies had excellent methodological quality. A meta-analysis revealed that different sources of MSCs improved knee function and pain more effectively among patients suffering from knee OA (KOA) than controls. The results of the network meta-analysis showed the following: short-term functional improvement (the indexes were evaluated after 6 months of follow-up) (WOMAC total score: bone marrow-derived MSC (BMMSC) vs. adipose-derived MSC (ADMSC) (mean difference (MD) = -20.12, 95% confidence interval (CI) -125.24 to 42.88), umbilical cord-derived MSC (UCMSC) (MD = -7.81, 95% CI -158.13 to 74.99); WOMAC stiffness: BMMSC vs. ADMSC (MD = -0.51, 95% CI -7.27 to 4.29), UCMSC (MD = -0.75, 95% CI -9.74 to 6.63); WOMAC functional limitation: BMMSC vs. ADMSC (MD = -12.22, 95% CI -35.05 to 18.86), UCMSC (MD = -9.31, 95% CI -44.26 to 35.27)). Long-term functional improvement (the indexes were evaluated after 12 months of follow-up) (WOMAC total: BMMSC vs. ADMSC (MD = -176.77, 95% CI -757.1 to 378.25), UCMSC (MD = -181.55, 95% CI -937.83 to 541.13); WOMAC stiffness: BMMSC vs. ADMSC (MD = -0.5, 95% CI -26.05 to 18.61), UCMSC (MD = -1.03, 95% CI -30.44 to 21.69); WOMAC functional limitation: BMMSC vs. ADMSC (MD = -5.18, 95% CI -316.72 to 177.1), UCMSC (MD = -8.33, 95% CI -358.78 to 218.76)). Short-term pain relief (the indexes were evaluated after 6 months of follow-up) (VAS score: UCMSC vs. BMMSC (MD = -10.92, 95% CI -31.79 to 12.03), ADMSC (MD = -14.02, 95% CI -36.01 to 9.81), PLMSC (MD = -17.09, 95% CI -46.31 to 13.17); WOMAC pain relief: BMMSC vs. ADMSC (MD = -11.42, 95% CI -39.52 to 11.77), UCMSC (MD = -6.73, 95% CI -47.36 to 29.15)). Long-term pain relief (the indexes were evaluated after 12 months of follow-up) (VAS score: BMMSC vs. UCMSC (MD = -4.33, 95% CI -36.81 to 27.08), ADMSC (MD = -11.43, 95% CI -37.5 to 13.42); WOMAC pain relief: UCMSC vs. ADMSC (MD = 0.23, 95% CI -37.87 to 38.11), BMMSC (MD = 5.89, 95% CI -25.39 to 51.41)). According to the GRADE scoring system, WOMAC, VAS, and AE scores were of low quality.

Conclusion

Meta-analysis suggests MSCs can effectively treat KOA by improving pain and knee function compared to control groups. In terms of functional improvement in KOA patients, both short-term (6-month follow-up) and long-term (12-month follow-up) results indicated that while the differences between most treatments were not statistically significant, bone marrow-derived MSCs may have some advantages over other sources of MSCs. Additionally, BM-MSCs and UC-MSCs may offer certain benefits over ADMSCs in terms of pain relief for KOA patients, although the variances between most studies were not statistically significant. Therefore, this study suggests that BM-MSCs may present clinical advantages over other sources of MSCs.

Extracellular vesicles derived from mesenchymal stem cells mediate extracellular matrix remodeling in osteoarthritis through the transport of microRNA-29a

BACKGROUND

Knee osteoarthritis (KOA) is a common orthopedic condition with an uncertain etiology, possibly involving genetics and biomechanics. Factors like changes in chondrocyte microenvironment, oxidative stress, inflammation, and immune responses affect KOA development. Early-stage treatment options primarily target symptom relief. Mesenchymal stem cells (MSCs) show promise for treatment, despite challenges. Recent research highlights microRNAs (miRNAs) within MSC-released extracellular vesicles that can potentially promote cartilage regeneration and hinder KOA progression. This suggests exosomes (Exos) as a promising avenue for future treatment. While these findings emphasize the need for effective KOA progression management, further safety and efficacy validation for Exos is essential.

AIM

To explore miR-29a's role in KOA, we'll create miR-29a-loaded vesicles, testing for early treatment in rat models.

METHODS

Extraction of bone marrow MSC-derived extracellular vesicles, preparation of engineered vesicles loaded with miR-29a using ultrasonication, and identification using quantitative reverse transcription polymerase chain reaction; after establishing a rat model of KOA, rats were randomly divided into three groups: Blank control group injected with saline, normal extracellular vesicle group injected with normal extracellular vesicle suspension, and engineered extracellular vesicle group injected with engineered extracellular vesicle suspension. The three groups were subjected to general behavioral observation analysis, imaging evaluation, gross histological observation evaluation, histological detection, and immunohistochemical detection to compare and evaluate the progress of various forms of arthritis.

RESULTS

General behavioral observation results showed that the extracellular vesicle group and engineered extracellular vesicle group had better performance in all four indicators of pain, gait, joint mobility, and swelling compared to the blank control group. Additionally, the engineered extracellular vesicle group had better pain relief at 4 wk and better knee joint mobility at 8 wk compared to the normal extracellular vesicle group. Imaging examination results showed that the blank control group had the fastest progression of arthritis, the normal extracellular vesicle group had a relatively slower progression, and the engineered extracellular vesicle group had the slowest progression. Gross histological observation results showed that the blank control group had the most obvious signs of arthritis, the normal extracellular vesicle group showed signs of arthritis, and the engineered extracellular vesicle group showed no significant signs of arthritis. Using the Pelletier gross score evaluation, the engineered extracellular vesicle group had the slowest progression of arthritis. Results from two types of staining showed that the articular cartilage of rats in the normal extracellular vesicle and engineered extracellular vesicle groups was significantly better than that of the blank control group, and the engineered extracellular vesicle group had the best cartilage cell and joint surface condition. Immunohistochemical detection of type II collagen and proteoglycan showed that the extracellular matrix of cartilage cells in the normal extracellular vesicle and engineered extracellular vesicle groups was better than that of the blank control group. Compared to the normal extracellular vesicle group, the engineered extracellular vesicle group had a better regulatory effect on the extracellular matrix of cartilage cells.

CONCLUSION

Engineered Exos loaded with miR-29a can exert anti-inflammatory effects and maintain extracellular matrix stability, thereby protecting articular cartilage, and slowing the progression of KOA.

Towards a Transferable Modeling Method of the Knee to Distinguish Between Future Healthy Joints from Osteoarthritic Joints: Data from the Osteoarthritis Initiative

Computational models can be used to predict the onset and progression of knee osteoarthritis. Ensuring the transferability of these approaches among computational frameworks is urgent for their reliability. In this work, we assessed the transferability of a template-based modeling strategy, based on the finite element (FE) method, by implementing it on two different FE softwares and comparing their results and conclusions. For that, we simulated the knee joint cartilage biomechanics of 154 knees using healthy baseline conditions and predicted the degeneration that occurred after 8 years of follow-up. For comparisons, we grouped the knees using their Kellgren-Lawrence grade at the 8-year follow-up time and the simulated volume of cartilage tissue that exceeded age-dependent thresholds of maximum principal stress. We considered the medial compartment of the knee in the FE models and used ABAQUS and FEBio FE softwares for simulations. The two FE softwares detected different volumes of overstressed tissue in corresponding knee samples (p < 0.01). However, both programs correctly distinguished between the joints that remained healthy and those that developed severe osteoarthritis after the follow-up (AUC = 0.73). These results indicate that different software implementations of a template-based modeling method similarly classify future knee osteoarthritis grades, motivating further evaluations using simpler cartilage constitutive models and additional studies on the reproducibility of these modeling strategies.

Treatment with Mesenchymal Stem Cell-Derived Nanovesicle-Containing Gelatin Methacryloyl Hydrogels Alleviates Osteoarthritis by Modulating Chondrogenesis and Macrophage Polarization

Osteoarthritis is a degenerative disorder that can severely affect joints, and new treatment strategies are urgently needed. Administration of mesenchymal stem cell (MSC)-derived exosomes is a promising therapeutic strategy in osteoarthritis treatment. However, the poor yield of exosomes is an obstacle to the use of this modality in the clinic. Herein, a promising strategy is developed to fabricate high-yield exosome-mimicking MSC-derived nanovesicles (MSC-NVs) with enhanced regenerative and anti-inflammatory capabilities. MSC-NVs are prepared using an extrusion approach and are found to increase chondrocyte and human bone marrow MSC differentiation, proliferation, and migration, in addition to inducing M2 macrophage polarization. Furthermore, gelatin methacryloyl (GelMA) hydrogels loaded with MSC-NVs (GelMA-NVs) are formulated, which exhibit sustained release of MSC-NVs and are shown to be biocompatible with excellent mechanical properties. In a mouse osteoarthritis model constructed by surgical destabilization of the medial meniscus (DMM), GelMA-NVs effectively ameliorate osteoarthritis severity, reduce the secretion of catabolic factors, and enhance matrix synthesis. Furthermore, GelMA-NVs induce M2 macrophage polarization and inflammatory response inhibition in vivo. The findings demonstrate that GelMA-NVs hold promise for osteoarthritis treatment through modulation of chondrogenesis and macrophage polarization.

Echinacoside alleviates osteoarthritis in rats by activating the Nrf2-HO-1 signaling pathway

OBJECTIVE

Osteoarthritis (OA) is a progressive disease characterized by degeneration of cartilage and echinacoside (Ech) has anti-inflammatory and antioxidant effects in various human diseases. This study aimed to reveal the effect and potential mechanism of Ech on OA.

MATERIALS AND METHODS

The in vitro OA model was established by rat chondrocytes treated with IL-1β, and the in vivo OA model was established by anterior cruciate ligament transaction. The effect of Ech on the viability, inflammatory response, extracellular matrix (ECM) degradation, and oxidative stress of IL-1β-treated rat chondrocytes were evaluated by Cell Counting Kit-8 assay, enzyme-linked immunosorbent assay, quantitative real-time PCR, Western blot, and immunofluorescence assay. Meanwhile, the mechanism of Ech was assessed using Western blot, Cell Counting Kit-8 assay, enzyme-linked immunosorbent assay, and immunofluorescence analysis. Moreover, the function of Ech in vivo was analyzed in rat models of OA.

RESULTS

Functionally, Ech enhanced the viability of rat chondrocytes, repressed the inflammatory response and ECM degradation of rat chondrocytes induced by IL-1β with restrained oxidative stress. Mechanically, Ech repressed IL-1β-induced chondrocyte injury by activating the Nrf2/HO-1 signaling pathway. Meanwhile, Ech alleviated the degree of articular cartilage injury in rats and exerted protective effects on the rat model of OA in vivo.

DISCUSSION AND CONCLUSIONS

Ech alleviated OA in rats by activating the Nrf2-HO-1 signaling pathway.

hBMSC-Derived Extracellular Vesicles Attenuate IL-1β-Induced Catabolic Effects on OA-Chondrocytes by Regulating Pro-inflammatory Signaling Pathways

Background: Human bone marrow-derived mesenchymal stromal cells (hBMSCs) provide a promising therapeutic approach in the cell-based therapy of osteoarthritis (OA). However, several disadvantages evolved recently, including immune responses of the host and regulatory hurdles, making it necessary to search for alternative treatment options. Extracellular vesicles (EVs) are released by multiple cell types and tissues into the extracellular microenvironment, acting as message carriers during intercellular communication. Here, we investigate putative protective effects of hBMSC-derived EVs as a cell-free approach, on IL-1β-stimulated chondrocytes obtained from OA-patients.

Methods: EVs were harvested from the cell culture supernatant of hBMSCs by a sequential ultracentrifugation process. Western blot, scanning electron microscopy (SEM), and nanoparticle tracking analysis (NTA) were performed to characterize the purified particles as EVs. Intracellular incorporation of EVs, derived from PHK26-labeled hBMSCs, was tested by adding the labeled EVs to human OA chondrocytes (OA-CH), followed by fluorescence microscopy. Chondrocytes were pre-stimulated with IL-1β for 24 h, followed by EVs treatment for 24 h. Subsequently, proliferation, apoptosis, and migration (wound healing) were analyzed via BrdU assay, caspase 3/7 assay, and scratch assay, respectively. With qRT-PCR, the relative expression level of anabolic and catabolic genes was determined. Furthermore, immunofluorescence microscopy and western blot were performed to evaluate the protein expression and phosphorylation levels of Erk1/2, PI3K/Akt, p38, TAK1, and NF-κB as components of pro-inflammatory signaling pathways in OA-CH.

Results: EVs from hBMSCs (hBMSC-EVs) promote proliferation and reduce apoptosis of OA-CH and IL-1β-stimulated OA-CH. Moreover, hBMSC-EVs attenuate IL-1β-induced reduction of chondrocyte migration. Furthermore, hBMSC-EVs increase gene expression of PRG4, BCL2, and ACAN (aggrecan) and decrease gene expression of MMP13, ALPL, and IL1ß in OA-CH. Notably, COL2A1, SOX9, BCL2, ACAN, and COMP gene expression levels were significantly increased in IL-1β⁺ EV groups compared with those IL-1β groups without EVs, whereas the gene expression levels of COLX, IL1B, MMP13, and ALPL were significantly decreased in IL-1β⁺ EV groups compared to IL-1β groups without EVs. In addition, the phosphorylation status of Erk1/2, PI3K/Akt, p38, TAK1, and NF-κB signaling molecules, induced by IL-1β, is prevented by hBMSC- EVs.

Conclusion: EVs derived from hBMSCs alleviated IL-1β-induced catabolic effects on OA-CH via promoting proliferation and migration and reducing apoptosis, probably via downregulation of IL-1ß-activated pro-inflammatory Erk1/2, PI3K/Akt, p38, TAK1, and NF-κB signaling pathways. EVs released from BMSCs may be considered as promising cell-free intervention strategy in cartilage regenerative medicine, avoiding several adverse effects of cell-based regenerative approaches.

Knee joint biomechanics of patients with unilateral total knee arthroplasty during stationary cycling

Stationary cycling is typically recommended following total knee arthroplasty (TKA) operations. However, knee joint biomechanics during cycling remains mostly unknown for TKA patients. Biomechanical differences between the replaced and non-replaced limb may inform applications of cycling in TKA rehabilitation. The purpose of this study was to examine the knee joint biomechanics of TKA patients during stationary cycling. Fifteen TKA participants cycled at 80 revolutions per minute and workrates of 80 W and 100 W while kinematics (240 Hz) and pedal reaction forces using a pair of instrumented pedals (1200 Hz) were collected. A 2x2 (limb × workrate) repeated measures ANOVA was run with an alpha of 0.05. Peak knee extension moment (KEM, p = 0.034) and vertical pedal reaction force (p = 0.038) were significantly reduced in the replaced limbs compared to non-replaced limbs by 21.3% and 5.3%, respectively. Peak KEM did not change for TKA patients with the increased workrate (p = 0.750). However, both peak hip extension moment (p = 0.009) and ankle plantarflexion moment (p = 0.017) increased due to increased workrate. Patients following TKA showed similar decreases in peak KEM and vertical pedal reaction force in their replaced compared to non-replaced limbs, as previously seen in gait. Patients of TKA may rely on their hip and ankle extensors to increases in workrate. Increasing intensity by 20 W did not exacerbate any inter-limb differences for peak KEM and vertical PRF.

Bone marrow mesenchymal stem cell-derived exosomes protect cartilage damage and relieve knee osteoarthritis pain in a rat model of osteoarthritis

Background

This study aimed to investigate the effect of bone marrow mesenchymal stem cell (BMSC)-derived exosome injection on cartilage damage and pain relief in both in vitro and in vivo models of osteoarthritis (OA).

Methods

The BMSCs were extracted from rat bone marrow of the femur and tibia. Chondrocytes were treated with IL-1β to establish the in vitro model of OA. Chondrocyte proliferation and migration were assessed by CCK-8 and transwell assay, respectively. A rat model of OA was established by injection of sodium iodoacetate. At 6 weeks after the model was established, the knee joint specimens and dorsal root ganglion (DRG) of rats were collected for histologic analyses. For pain assessment, paw withdrawal threshold (PWT) and paw withdrawal latency (PWL) were evaluated before model establishment and at 1, 2, 4, and 6 weeks after model establishment.

Results

Exosomes can be endocytosed with the chondrocytes in vitro. Exosome treatment significantly attenuated the inhibitory effect of IL-1β on the proliferation and migration of chondrocytes. Exosome pre-treatment significantly attenuated IL-1β-induced downregulation of COL2A1 and ACAN and upregulation of MMP13 and ADAMTS5. In the animal study, exosome treatment significantly upregulated COL2A1 protein and downregulated MMP13 protein in the cartilage tissue of the OA rat. At weeks 2, 4, and 6, the PWL value was significantly improved in the exosome-treated OA rats as compared with the untreated OA animals. Moreover, exosome treatment significantly alleviated the upregulation of CGRP and iNOS in the DRG tissue of OA rats.

Conclusion

BMSC-derived exosomes can effectively promote cartilage repair and extracellular matrix synthesis, as well as alleviate knee pain in the OA rats.

Intergenerational Transmission of Diet-Induced Obesity, Metabolic Imbalance, and Osteoarthritis in Mice

OBJECTIVE

Obesity and osteoarthritis (OA) are 2 major public health issues affecting millions of people worldwide. Whereas parental obesity affects the predisposition to diseases such as cancer or diabetes in children, transgenerational influences on musculoskeletal conditions such as OA are poorly understood. This study was undertaken to assess the intergenerational effects of a parental/grandparental high-fat diet on the metabolic and skeletal phenotype, systemic inflammation, and predisposition to OA in 2 generations of offspring in mice.

METHODS

Metabolic phenotype and predisposition to OA were investigated in the first and second (F1 and F2) generations of offspring (n = 10-16 mice per sex per diet) bred from mice fed a high-fat diet (HFD) or a low-fat control diet. OA was induced by destabilizing the medial meniscus. OA, synovitis, and adipose tissue inflammation were determined histologically, while bone changes were measured using micro-computed tomography. Serum and synovial cytokines were measured by multiplex assay.

RESULTS

Parental high-fat feeding showed an intergenerational effect, with inheritance of increased weight gain (up to 19% in the F1 generation and 9% in F2), metabolic imbalance, and injury-induced OA in at least 2 generations of mice, despite the fact that the offspring were fed the low-fat diet. Strikingly, both F1 and F2 female mice showed an increased predisposition to injury-induced OA (48% higher predisposition in F1 and 19% in F2 female mice fed the HFD) and developed bone microarchitectural changes that were attributable to parental and grandparental high-fat feeding.

CONCLUSION

The results of this study reveal a detrimental effect of parental HFD and obesity on the musculoskeletal integrity of 2 generations of offspring, indicating the importance of further investigation of these effects. An improved understanding of the mechanisms involved in the transmissibility of diet-induced changes through multiple generations may help in the development of future therapies that would target the effects of obesity on OA and related conditions.

Exosomes from embryonic mesenchymal stem cells alleviate osteoarthritis through balancing synthesis and degradation of cartilage extracellular matrix

Background

Mesenchymal stem cell therapy for osteoarthritis (OA) has been widely investigated, but the mechanisms are still unclear. Exosomes that serve as carriers of genetic information have been implicated in many diseases and are known to participate in many physiological processes. Here, we investigate the therapeutic potential of exosomes from human embryonic stem cell-induced mesenchymal stem cells (ESC-MSCs) in alleviating osteoarthritis (OA).

Methods

Exosomes were harvested from conditioned culture media of ESC-MSCs by a sequential centrifugation process. Primary mouse chondrocytes treated with interleukin 1 beta (IL-1β) were used as an in vitro model to evaluate the effects of the conditioned medium with or without exosomes and titrated doses of isolated exosomes for 48 hours, prior to immunocytochemistry or western blot analysis. Destabilization of the medial meniscus (DMM) surgery was performed on the knee joints of C57BL/6 J mice as an OA model. This was followed by intra-articular injection of either ESC-MSCs or their exosomes. Cartilage destruction and matrix degradation were evaluated with histological staining and OARSI scores at the post-surgery 8 weeks.

Results

We found that intra-articular injection of ESC-MSCs alleviated cartilage destruction and matrix degradation in the DMM model. Further in vitro studies illustrated that this effect was exerted through ESC-MSC-derived exosomes. These exosomes maintained the chondrocyte phenotype by increasing collagen type II synthesis and decreasing ADAMTS5 expression in the presence of IL-1β. Immunocytochemistry revealed colocalization of the exosomes and collagen type II-positive chondrocytes. Subsequent intra-articular injection of exosomes derived from ESC-MSCs successfully impeded cartilage destruction in the DMM model.

Conclusions

The exosomes from ESC-MSCs exert a beneficial therapeutic effect on OA by balancing the synthesis and degradation of chondrocyte extracellular matrix (ECM), which in turn provides a new target for OA drug and drug-delivery system development.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0632-0) contains supplementary material, which is available to authorized users.

The relationship between smoking and knee osteoarthritis in the Osteoarthritis Initiative

OBJECTIVE

To estimate the extent that smoking history is associated with symptoms and disease progression among individuals with radiographically confirmed knee Osteoarthritis (OA).

METHOD

Both cross-sectional (baseline) and longitudinal studies employed data from the Osteoarthritis Initiative (OAI) (n = 2250 participants). Smoking history was assessed at baseline with 44% current or former smokers. The Western Ontario and McMaster Universities Arthritis Index (WOMAC) was used to measure knee pain, stiffness, and physical function. Disease progression was measured using joint space width (JSW). We used adjusted multivariable linear models to examine the relationship between smoking status and exposure in pack years (PY) with symptoms and JSW at baseline. Changes in symptoms and JSW over time were further assessed.

RESULTS

In cross-sectional analyses, compared to never-smokers high PY (≥15 PY) was associated with slightly greater pain (beta 0.36, 95% CI: 0.01-0.71) and stiffness (beta 0.20, 95% CI: 0.03-0.37); and low PY (<15 PY) was associated with better JSW (beta 0.15, 95% CI: 0.02-0.28). Current smoking was associated with greater pain (beta 0.59, 95% CI: 0.04-1.15) compared to never-smokers. These associations were not confirmed in the longitudinal study. Longitudinally, no associations were found between high or low PY or baseline smoking status with changes in symptoms (at 72 months) or JSW (at 48 months).

CONCLUSION

Cross-sectional findings are likely due residual confounding. The more robust longitudinal analysis found no associations between smoking status and symptoms or JSW. Long-term smoking provides no benefits to knee OA patients while exposing them to other well-documented serious health risks.

State of the evidence

PURPOSE OF REVIEW

This review focuses on recent studies of osteoarthritis epidemiology, including research on prevalence, incidence, and a broad array of potential risk factors at the person level and joint level.

RECENT FINDINGS

Studies continue to illustrate the high impact of osteoarthritis worldwide, with increasing incidence. Person-level risk factors with strong evidence regarding osteoarthritis incidence and/or progression include age, sex, socioeconomic status, family history, and obesity. Joint-level risk factors with strong evidence for incident osteoarthritis risk include injury and occupational joint loading; the associations of injury and joint alignment with osteoarthritis progression are compelling. Moderate levels of physical activity have not been linked to increased osteoarthritis risk. Some topics of high recent interest or emerging evidence for association with osteoarthritis include metabolic pathways, vitamins, joint shape, bone density, limb length inequality, muscle strength and mass, and early structural damage.

SUMMARY

Osteoarthritis is a complex, multifactorial disease, and there is still much to learn regarding mechanisms underlying incidence and progression. However, there are several known modifiable and preventable risk factors, including obesity and joint injury; efforts to mitigate these risks can help to lessen the impact of osteoarthritis.