Pathogenesis and clinical management of obesity-related knee osteoarthritis: Impact of mechanical loading

Transcriptomics and metabolomics: Challenges of studying obesity in osteoarthritis

Objective

Obesity is a leading risk factor for both the incidence and progression of osteoarthritis (OA). Omic technologies, including transcriptomics and metabolomics are capable of identifying RNA and metabolite profiles in tissues and biofluids of OA patients. The objective of this review is to highlight studies using transcriptomics and metabolomics that contribute to our understanding of OA pathology in relation to obesity.

Design

We conducted a targeted search of PUBMED for articles, and GEO for datasets, published up to February 13, 2024, screening for those using high-throughput transcriptomic and metabolomic techniques to study human or pre-clinical animal model tissues or biofluids related to obesity-associated OA. We describe relevant studies and discuss challenges studying obesity as a disease-related factor in OA.

Results

Of the 107 publications identified by our search criteria, only 15 specifically used transcriptomics or metabolomics to study joint tissues or biofluids in obesity-related OA. Specific transcriptomic and metabolomic signatures associated with obesity-related OA have been defined in select local joint tissues, biofluids and other biological material. However, considerable challenges exist in understanding contributions of obesity-associated modifications of transcriptomes and metabolomes related to OA, including sociodemographic, anthropometric, dietary and molecular redundancy-related factors.

Conclusions

A number of additional transcriptomic and metabolomic studies are needed to comprehensively understand how obesity affects OA incidence, progression and outcomes. Integration of transcriptome and metabolome signatures from multiple tissues and biofluids, using network-based approaches will likely help to better define putative therapeutic targets that could enable precision medicine approaches to obese OA patients.

Hip and pelvic geometry as predictors of knee osteoarthritis severity

Malalignment is one of the most critical risk factors for knee osteoarthritis (KOA). Biomechanical factors such as knee varus or valgus, hip-knee-ankle angle, and femoral anteversion affect KOA severity. In this study, we aimed to investigate KOA severity predictive factors based on hip and pelvic radiographic geometry. In this cross-sectional study, 125 patients with idiopathic KOA were enrolled. Two investigators evaluated the knee and pelvic radiographs of 125 patients, and 16 radiological parameters were measured separately. KOA severity was categorized based on the medial tibiofemoral joint space widths (JSW). Based on JSW measurements, 16% (n = 40), 8.8% (n = 22), 16.4% (n = 41), and 56.8% (n = 147) were defined as grades 0, 1, 2, 3, respectively. There were significant differences between the JSW groups with respect to hip axis length, femoral neck-axis length, acetabular width, neck shaft angle (NSA), outer pelvic diameter, midpelvis-caput distance, acetabular-acetabular distance, and femoral head to femoral head length (P < .05). Two different functions were obtained using machine learning classification and logistic regression, and the accuracy of predicting was 74.4% by using 1 and 89.6% by using both functions. Our findings revealed that some hip and pelvic geometry measurements could affect the severity of KOA. Furthermore, logistic functions using predictive factors of hip and pelvic geometry can predict the severity of KOA with acceptable accuracy, and it could be used in clinical decisions.

Unicompartmental knee arthroplasty in obese patients, poorer survivorship at 15 years

Introduction

The preclusion of obese patients from unicompartmental knee arthroplasty (UKA) has increasingly been challenged. This study aimed to evaluate the impact of Body Mass Index (BMI) on UKA at 15-year follow-up.

Materials and methods

169 unilateral UKA patients from 2003 to 2007 were followed-up prospectively for at least 15 years. 70 patients were left for analysis after accounting for patient demise, revision surgery and loss to follow-up. 48 of these patients (69%) were in the Control group (BMI <30 kg/m2) and 22 (31%) were in the Obese group (BMI ≥30 kg/m2). Patients were assessed before and after operation using the Knee Society Function Score (KSFS), Knee Society Knee Score (KSKS), Oxford Knee Score (OKS), and Physical (PCS) and Mental (MCS) component of the Short Form 12. Survivorship analysis was also performed.

Results

Obese patients went through UKA at an earlier age than the non-obese patients (54.7 ± 4.7 years compared to 59.9 ± 7.8 years, p = 0.005). At 2, 10, and 15-year follow-up, both groups achieved clinically significant improvements in outcomes. There was no significant association found between obesity and outcome using multiple linear regression. While propensity matching found PCS improvement at 2 years to be greater in obese patients, no significant association between obesity and 15-year outcome was found. All 13 patients who required revision, underwent total knee arthroplasty (TKA). The overall 15-year survivorship was 74.2% within the obese group and 92.4% within the control group.

Conclusion

Compared to non-obese patients, obese patients had poorer 15-year survivorship with greater odds of requiring revision surgery. However, assuming implant survival, obese patients can expect a non-inferior outcome relative to their non-obese counterparts in all patient reported outcome measures 15 years after surgery.

Evaluation of Osteoarthritis Disease Burden in China During 1990-2019 and Forecasting Its Trend Over the Future 25 Years

OBJECTIVE

This study aimed to estimate the temporal trend of osteoarthritis (OA) burden in China by age, sex, and joint sites from 1990 to 2019 and predict the long-term trend over the next 25 years.

METHODS

Using data from the Global Burden of Disease Study 2019, we estimated incident cases, prevalent cases, disability-adjusted life years (DALYs) of OA, and DALYs of OA attributed to high body mass index (BMI), as well as corresponding age-standardized rates (ASRs) for aforementioned indicies. Estimated annual percentage change (EAPC) and Nordpred age-period-cohort model were used to describe temporal trend changes and predict future disease burden.

RESULTS

From 1990 to 2019, the ASR of OA incidence increased from 472.53 per 100,000 to 509.84 per 100,000 people (EAPC: 0.36, 95% confidence interval [CI] 0.29-0.44); the ASR of OA prevalence increased from 5,880.58 per 100,000 to 6,330.06 per 100,000 people (EAPC 0.35, 95% CI 0.28-0.42); the ASR of OA DALYs increased from 206.38 per 100,000 to 224.78 per 100,000 people (EAPC 0.40, 95% CI 0.32-0.48). The ASR of OA DALYs attributed to high BMI increased rapidly, especially in men and patients with hip OA. Projections suggest an increasing trend in the incidence, prevalence, and DALYs of OA from 2019 to 2044, with the prevalent cases and DALYs of OA in China expected to increase by approximately 1.5 times over the next 25 years.

CONCLUSION

The disease burden of OA has increased in China over the past 30 years and is expected to continue rising over the next 25 years.

Super-Obesity is Associated With an Increased Risk of Complications Following Primary Total Knee Arthroplasty

BACKGROUND

Obesity, defined as a body mass index (BMI) ≥ 30, is an ever-growing epidemic, with > 35% of adults in the United States currently classified as obese. Super-obese individuals, defined as those who have a BMI ≥ 50, are the fastest-growing portion of this group. This study sought to quantify the infection risk as well as the incidence of surgical, medical, and thromboembolic complications among super-obese patients undergoing total knee arthroplasty (TKA).

METHODS

An all-payer claims database was used to identify patients who underwent elective, primary TKA between 2016 and 2021. Patients who had a BMI ≥ 50 were compared to those who had a normal BMI of 18 to 25. Demographics and the incidence of 90-days postoperative complications were compared between the 2 groups. Univariate analysis and multivariable regression were used to assess differences between groups.

RESULTS

In total, 3,376 super-obese TKA patients were identified and compared to 17,659 patients who had a normal BMI. Multivariable analysis indicated that the super-obese cohort was at an increased postoperative risk of periprosthetic joint infection (adjusted odds ratio [aOR] 3.7, 95% confidence interval [CI]: 2.1 to 6.4, P < .001), pulmonary embolism (aOR 2.2, 95%-CI: 1.0 to 5.0, P = .047), acute respiratory failure (aOR 4.1, 95%-CI: 2.7 to 6.1, P < .001), myocardial infarction (aOR 2.5, 95%-CI: 1.1 to 5.8, P = .026), wound dehiscence (aOR 2.3, 95%-CI: 1.4 to 3.8, P = .001), and acute renal failure (aOR 3.2, 95%-CI: 2.4 to 4.2, P < .001) relative to patients who have normal BMI.

CONCLUSIONS

Super-obese TKA patients are at an elevated risk of postoperative infectious, surgical, medical, and thromboembolic complications. As such, risk stratification, as well as appropriate medical management and optimization, is of utmost importance for this high-risk group.

Preoperative weight loss interventions before total hip and knee arthroplasty: a systematic review of randomized controlled trials

BACKGROUND

The high co-prevalence of obesity and end-stage osteoarthritis requiring arthroplasty, with the former being a risk factor for complications during arthroplasty, has led to increasing interest in employing preoperative weight loss interventions such as bariatric surgery and diet modification. However, the current evidence is conflicting, and this study aimed to investigate the effect of weight loss intervention before arthroplasty in prospective randomized controlled trials.

METHODS

Four electronic databases (MEDLINE, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials) were searched for prospective randomized controlled trials that compared weight loss interventions with usual care from inception to October 2023 by following the PRISMA guidelines. The Cochrane risk of bias tool and GRADE framework were used to assess the quality of the studies. Meta-analyses were performed when sufficient data were available from 2 or more studies.

RESULTS

Three randomized controlled trials involving 198 patients were identified. Two studies employed diet modification, and one study utilized bariatric surgery. All three studies reported significant reductions in body weight and body mass index (BMI), and intervention groups had fewer postoperative complications. There was no difference in the length of stay between the intervention group and the control group. Variable patient-reported outcome measures were used by different research groups.

CONCLUSION

Weight loss intervention can achieve significant reductions in body weight and body mass index before arthroplasty, with fewer postoperative complications reported. Further studies with different populations could confirm the effect of these interventions among populations with different obesity characteristics.

Predictors, Protective Factors, and Adverse Outcomes of Joint Pain among Malaysian Community-Dwelling Older Adults: Findings from the LRGS-TUA Longitudinal Study

Background: Joint pain has been recognized as one of the major causes of limitations in mobility, functional decline, and consequently declined quality of life in older adults. Hence, this study aimed to identify the predictors, protective factors, and adverse outcomes of joint pain in community-dwelling older adults. Methods: In this Long-term Research Grant Scheme-Towards Useful Ageing (LRGS-TUA) longitudinal study, a total of 1005 older participants aged 60 years and above who were successfully followed up after five years were included in the analysis. The participants self-reported their joint pain status at baseline and during the fifth year. Subsequently, the baseline characteristics were used to predict changes in joint pain status. Adverse outcomes related to joint pain were evaluated based on the participants' joint pain statuses. Results: Results showed that being female, having diabetes mellitus, and higher body mass index were associated with the incidence of joint pain. Meanwhile, increased intake of pantothenic acid and higher levels of blood albumin levels were associated with recovery from joint pain. Participants with persistent joint pain at baseline and follow-up showed higher levels of depression and disability compared to individuals who never experience any joint pain. However, participants who had recovered from joint pain did not differ significantly from those without joint pain at baseline and follow-up in these measures. Conclusions: By identifying the modifiable risk factors, factors associated with recovery, and adverse outcomes related to joint pain, this study adds to current evidence that may contribute to further management strategies for joint pain in older adults.

Female obesity: clinical and psychological assessment toward the best treatment

Obesity is a heterogeneous condition which results from complex interactions among sex/gender, sociocultural, environmental, and biological factors. Obesity is more prevalent in women in most developed countries, and several clinical and psychological obesity complications show sex-specific patterns. Females differ regarding fat distribution, with males tending to store more visceral fat, which is highly correlated to increased cardiovascular risk. Although women are more likely to be diagnosed with obesity and appear more motivated to lose weight, as confirmed by their greater representation in clinical trials, males show better outcomes in terms of body weight and intra-abdominal fat loss and improvements in the metabolic risk profile. However, only a few relatively recent studies have investigated gender differences in obesity, and sex/gender is rarely considered in the assessment and management of the disease. This review summarizes the evidence of gender differences in obesity prevalence, contributing factors, clinical complications, and psychological challenges. In addition, we explored gender differences in response to obesity treatments in the specific context of new anti-obesity drugs.

Exploration beyond osteoarthritis: the association and mechanism of its related comorbidities

Osteoarthritis is the most prevalent age-related degenerative joint disease and a leading cause of pain and disability in aged people. Its etiology is multifaceted, involving factors such as biomechanics, pro-inflammatory mediators, genetics, and metabolism. Beyond its evident impact on joint functionality and the erosion of patients' quality of life, OA exhibits symbiotic relationships with various systemic diseases, giving rise to various complications. This review reveals OA's extensive impact, encompassing osteoporosis, sarcopenia, cardiovascular diseases, diabetes mellitus, neurological disorders, mental health, and even cancer. Shared inflammatory processes, genetic factors, and lifestyle elements link OA to these systemic conditions. Consequently, recognizing these connections and addressing them offers opportunities to enhance patient care and reduce the burden of associated diseases, emphasizing the need for a holistic approach to managing OA and its complications.

Anthropometric measures of obesity in patients with knee joint pathology: Body surface area versus body mass index

BACKGROUND

Obesity is quantified using body mass index. Body surface area may provide a superior and more anthropometric method of quantifying obesity in patients with musculoskeletal knee disease. This study compares the effect of weight, height, age and gender on body mass index and body surface area in a population with orthopaedic knee disease.

METHODS

An observational cohort study was conducted of patients presenting with musculoskeletal knee disease. Associations between body mass index, body surface area, age, gender, height, weight and operative versus non-operative management were analysed.

RESULTS

A total of 151 patients were included. Body surface area was more strongly correlated to weight than body mass index (r = 0.98, p < 0.001 versus r = 0.84, p < 0.001). Body surface area also reflects height which body mass index under presents (r = 0.65, p < 0.001 versus r = -0.08, p = 0.35). Body mass index and body surface area were correlated with one another (r = 0.70, p < 0.001). Age was inversely correlated with body surface area (r = -0.20, p = 0.013) but not body mass index (r = 0.05, p = 0.585). Body mass index did not differ between males and females (30.1 versus 30.9, p = 0.37); however, BSA scores were significantly higher in males than females (2.11 versus 1.91, p < 0.001). Neither body surface area nor body mass index scores influenced operative versus non-operative treatment.

CONCLUSION

Body surface area could be a useful alternative to body mass index when considering obesity in patients with musculoskeletal knee pathology. Body surface area better reflects the effects of height, weight, age and gender than body mass index.

Surgical Interventions for the Management of Obesity-Related Joint Pain: A Narrative Review

Obesity-related joint pain is a common and debilitating condition that significantly impacts the quality of life, primarily due to the excess weight straining the joints. This results in inflammation and degeneration, which can cause pain, stiffness, and difficulty moving. We aimed to comprehensively review the literature discussing surgical interventions for obesity-related joint pain. We searched across databases (PubMed, Scopus, and Cochrane Library) to identify studies published between 2000 and 2023 that assessed surgical interventions for obesity-related joint pain. This review highlights the complex interplay of mechanical, inflammatory, and metabolic factors contributing to joint pain in obese individuals, highlighting both surgical and non-surgical interventions. Non-surgical interventions include weight loss, exercise, physical therapy, and medications. Surgical interventions include bariatric surgery and joint replacement surgery. Bariatric surgery significantly reduces body weight and improves the quality of life outcomes; however, multiple studies have found no improvement or worsening of joint pain post-surgery. Total joint arthroplasty has demonstrated good improvement in pain and function outcomes based on recent meta-analyses, although risks of complications are higher in obese patients. The treatment choice for obesity-related joint pain depends on the individual patient's circumstances. Non-surgical interventions are usually the first line of treatment. However, if these interventions are not effective, surgical interventions may be an option.

Factors predicting lower limb alignment after Oxford medial unicompartmental knee arthroplasty

This study aimed to identify the factors affecting hip-knee-ankle (HKA) angle following Oxford medial unicompartmental knee arthroplasty (MUKA). A retrospective analysis of 200 patients who underwent Oxford MUKA from June 2018 to October 2020 was conducted. Univariate and multivariate analyses were performed to investigate the impact of surgical and radiographic characteristics on the postoperative HKA angle. The mean HKA angle was 9.5 ± 4.3° before surgery and 3.6 ± 3.7° after surgery (p < 0.001). The postoperative HKA angle significantly correlated with the preoperative HKA angle, bearing size, tibial component alignment angle, and BMI (r = 0.71, p < 0.001; r =  - 0.24, p = 0.001; r = 0.21, p = 0.004; r =  - 0.18, p = 0.011). Multiple linear regression analysis revealed that the preoperative HKA angle (β = 0.68, p < 0.001), bearing size (β =  - 0.31, p < 0.001), tibial component alignment angle (β = 0.14, p = 0.003), and BMI (β =  - 0.09, p = 0.047) significantly affected the postoperative HKA angle. In conclusion, larger preoperative varus deformity, smaller bearing size, greater varus alignment of the tibial component, and lower BMI lead to greater postoperative varus alignment of the lower limb in Oxford MUKA. With this concept, surgeons can more accurately predict postoperative lower limb alignment and avoid malalignment in Oxford MUKA.

Knee osteoarthritis pendulum therapy: In vivo evaluation and a randomised, single-blind feasibility clinical trial

Background

Exercise is recommended as the first-line management for knee osteoarthritis (KOA); however, it is difficult to determine which specific exercises are more effective. This study aimed to explore the potential mechanism and effectiveness of a leg-swinging exercise practiced in China, called 'KOA pendulum therapy' (KOAPT). Intraarticular hydrostatic and dynamic pressure (IHDP) are suggested to partially explain the signs and symptoms of KOA. As such this paper set out to explore this mechanism in vivo in minipigs and in human volunteers alongside a feasibility clinical trial. The objective of this study is 1) to analyze the effect of KOAPT on local mechanical and circulation environment of the knee in experimental animals and healthy volunteers; and 2) to test if it is feasible to run a large sample, randomized/single blind clinical trial.

Methods

IHDP of the knee was measured in ten minipigs and ten volunteers (five healthy and five KOA patients). The effect of leg swinging on synovial blood flow and synovial fluid content depletion in minipigs were also measured. Fifty KOA patients were randomly divided into two groups for a feasibility clinical trial. One group performed KOAPT (targeting 1000 swings/leg/day), and the other performed walking exercise (targeting 4000 steps/day) for 12 weeks with 12 weeks of follow-up.

Results

The results showed dynamic intra-articular pressure changes in the knee joint, increases in local blood flow, and depletion of synovial fluid contents during pendulum leg swinging in minipigs. The intra-articular pressure in healthy human knee joints was -11.32 ± 0.21 (cmH2O), whereas in KOA patients, it was -3.52 ± 0.34 (cmH2O). Measures were completed by 100% of participants in all groups with 95-98% adherence to training in both groups in the feasibility clinical trial. There were significant decreases in the Oxford knee score in both KOAPT and walking groups after intervention (p < 0.01), but no significant differences between the two groups.

Conclusion

We conclude that KOAPT exhibited potential as an intervention to improve symptoms of KOA possibly through a mechanism of normalising mechanical pressure in the knee; however, optimisation of the method, longer-term intervention and a large sample randomized-single blind clinical trial with a minimal 524 cases are needed to demonstrate whether there is any superior benefit over other exercises.

The translational potential of this article

The research aimed to investigate the effect of an ancient leg-swinging exercise on knee osteoarthritis. A minipig animal model was used to establish the potential mechanism underlying the exercise of knee osteoarthritis pendulum therapy, followed by a randomised, single-blind feasibility clinical trial in comparison with a commonly-practised walking exercise regimen. Based on the results of the feasibility trial, a large sample clinical trial is proposed for future research, in order to develop an effective exercise therapy for KOA.

Quadriceps muscle reaction time in obese children

This study aimed to determine the influence of obesity, according to body mass index (BMI) and fat mass percentage, on quadriceps muscle reaction times. The study utilized a cross-sectional design. The sample size consisted of 42 schoolchildren (54.5% girls) aged 11 to 12 years old. Participant measurements included weight and height, which were used to categorize individuals based on BMI. Additionally, the electrical bioimpedance technique was employed to categorize participants based on their body fat percentage. A sudden destabilization test of the lower limb was performed to assess the reaction time of the rectus femoris, vastus medialis, and vastus lateralis muscles. The results show that overweight/obese children have a longer muscle reaction time for both the rectus femoris (β = 18.13; p = 0.048) and the vastus lateralis (β = 14.51; p = 0.042). Likewise, when the children were classified by percentage of body fat the results showed that overfat/obese children have a longer muscle reaction time for both the rectus femoris (β = 18.13; p = 0.048) and the vastus lateralis (β = 14.51; p = 0.042). Our results indicate that BMI and fat mass classification negativity alter the muscle reaction time in children. Overweight/obese or overfat/obese children showed longer reaction times in the rectus femoris and vastus lateralis muscles compared to children with normal weight. Based on these findings, it is suggested that in overweight and obese children, efforts not only focus on reducing body weight but that be complemented with training and/or rehabilitation programs that focus on preserving the normal physiological function of the musculoskeletal system.

Investigation of periodontitis, halitosis, xerostomia, and serological characteristics of patients with osteoarthritis and rheumatoid arthritis and identification of new biomarkers

Rheumatoid arthritis (RA) and osteoarthritis (OA) are two different types of arthritis. Within RA, the subsets between seronegative RA (snRA) and seropositive RA (spRA) represent distinct disease entities; however, identifying clear distinguishing markers between them remains a challenge. This study investigated and compared the oral health conditions in patients with RA and OA to clarify the differences from healthy controls. In addition, we investigated the serological characteristics of the patients, the factors that distinguished patients with RA from those with OA, and the main factors that differentiated between snRA and spRA patients. A total of 161 participants (mean age: 52.52 ± 14.57 years, 32 males and 129 females) were enrolled in this study and categorized as: normal (n = 33), OA (n = 31), and RA (n = 97). Patients with RA were divided into the following two subtypes: snRA (n = 18) and spRA (n = 79). Demographics, oral health, and serological characteristics of these patients were compared. The prevalence of periodontal diseases was significantly higher in patients with OA (100%) and RA (92.8%) than in healthy controls (0.0%). However, the presence of periodontal diseases was not utilized as a distinguishing factor between OA and RA. Xerostomia occurred more frequently in patients with RA (84.5%) than in patients with OA (3.2%) and healthy controls (0.0%) (all p < 0.001). ROC analysis revealed that periodontal disease was a very strong predictor in the diagnosis of OA compared to healthy controls, with an AUC value of 1.00 (p < 0.001). Additionally, halitosis (AUC = 0.746, 95% CI 0.621-0.871, p < 0.001) and female sex (AUC = 0.663, 95% CI 0.529-0.797, p < 0.05) were also significant predictors of OA. The strongest predictors of RA diagnosis compared to healthy controls were periodontal diseases (AUC = 0.964), followed by xerostomia (AUC = 0.923), age (AUC = 0.923), female sex (AUC = 0.660), and halitosis (AUC = 0.615) (all p < 0.05). Significant serological predictors of RA were anti-CCP Ab (AUC = 0.808), and RF (AUC = 0.746) (all p < 0.05). In multiple logistic regression analysis, xerostomia (odds ratio, OR: 8124.88, 95% CI 10.37-6368261.97, p-value = 0.008) and Anti-CCP Ab (OR: 671.33, 95% CI 2.18-207,074.02, p = 0.026) were significant predictors for RA compared to OA. When diagnosing spRA compared to snRA, anti-CCP Ab (AUC = 1.000, p < 0.001) and RF (AUC = 0.910, 95%CI 0.854-0.967, p < 0.001) had outstanding predictive performances. Therefore, clinicians and researchers should thoroughly evaluate the oral status of both OA and RA patients, alongside serological factors, and consider these elements as potential predictors.

Integration of risk factor polygenic risk score with disease polygenic risk score for disease prediction

Polygenic risk score (PRS) is useful for capturing an individual's genetic susceptibility. However, previous studies have not fully exploited the potential of the risk factor PRS (RFPRS) for disease prediction. We explored the potential of integrating disease-related RFPRSs with disease PRS to enhance disease prediction performance. We constructed 112 RFPRSs and analyzed the association of RFPRSs with diseases to identify disease-related RFPRSs in 700 diseases, using the UK Biobank dataset. We uncovered 6157 statistically significant associations between 247 diseases and 109 RFPRSs. We estimated the disease PRSs of 70 diseases that exhibited statistically significant heritability, to generate RFDiseasemetaPRS-a combined PRS integrating RFPRSs and disease PRS-and compare the prediction performance metrics between RFDiseasemetaPRS and disease PRS. RFDiseasemetaPRS showed better performance for Nagelkerke's pseudo-R2, odds ratio (OR) per 1 SD, net reclassification improvement (NRI) values and difference of R2 considered by variance of R2 in 31 out of 70 diseases. Additionally, we assessed risk classification between two models by examining OR between the top 10% and remaining 90% individuals for the 31 diseases; RFDiseasemetaPRS exhibited better R2, NRI and OR than disease PRS. These findings highlight the importance of utilizing RFDiseasemetaPRS, which can provide personalized healthcare and tailored prevention strategies.

Stemmed Tibial Fixation for Primary Total Knee Arthroplasty in Obese Patients-A National Registry Study

BACKGROUND

We investigated if the use of augmented tibial fixation with stems in primary total knee arthroplasty (TKA) in obese patients was associated with a difference in reason for revision, type of revision, or overall revision rate.

METHODS

Data from the Australian Orthopaedic Association National Joint Replacement Registry compared reason for revision, rate, and type of revision between primary TKA using stemmed tibial prostheses to nonstemmed prostheses, stratified by body mass index (BMI) and obesity. The cumulative percent revision was obtained using the Kaplan-Meier method, and Cox proportional hazards models estimated hazard ratios (HRs) adjusted for age and sex with 95% confidence intervals (CIs). All tests were 2-tailed at 5% statistical significance (P < .05). There were 66,508 procedures available for analyses.

RESULTS

Obese class 2 (BMI 35 to 39.99) had higher rates of revision in the stemmed group compared to the nonstemmed group (HR 1.44, 95% CI 1.00, 2.05, P = .047). There was no significant difference in revision rates between stemmed and nonstemmed tibial prostheses in any other BMI group. Primary TKA in obese patients (BMI ≥30) with a stem extension had a significantly higher rate of minor revisions compared to no stem extension (HR 1.31, 95% CI 1.03, 1.66, P = .025). There was no significant difference between stemmed and nonstemmed groups for major revision in obese patients and for minor or major revision in nonobese patients.

CONCLUSION

Using a tibial stem during primary TKA in obese patients is not associated with a lower rate of revision.

Association of body composition and physical activity with pain and function in knee osteoarthritis patients: a cross-sectional study

OBJECTIVE

The objective of this study is to delineate disparities between patients with knee osteoarthritis (KOA) based on obesity status, investigate the interplay among body composition, physical activity and knee pain/function in patients with KOA and conduct subgroup analyses focusing on those with KOA and obesity.

DESIGN

Cross-sectional study.

SETTING

Residents of eight communities in Shijiazhuang, Hebei Province, China, were surveyed from March 2021 to November 2021.

PARTICIPANTS

178 patients with symptomatic KOA aged 40 years or older were included.

MAIN OUTCOMES AND MEASURES

The primary outcome measure was knee pain, assessed using the Western Ontario and McMaster Universities Osteoarthritis Index-pain (WOMAC-P) scale. Secondary outcome measures included function, evaluated through the WOMAC-function (WOMAC-F) scale and the Five-Time-Sit-to-Stand Test (FTSST). Data analysis involved t-tests, Wilcoxon rank-sum tests, χ2 tests, linear and logistical regression analysis.

RESULTS

Participants (n=178) were 41-80 years of age (median: 65, P25-P75: 58-70), and 82% were female. Obese patients (n=103) had worse knee pain and self-reported function (p<0.05). In general patients with KOA, body fat mass was positively associated with bilateral knee pain (β=1.21 (95% CI 0.03 to 0.15)), WOMAC-P scores (β=0.25 (95% CI 0.23 to 1.22)), WOMAC-F scores (β=0.28 (95% CI 0.35 to 1.29)) and FTSST (β=0.19 (95% CI 0.03 to 0.42)), moderate-intensity to low-intensity physical activity was negatively associated with bilateral knee pain (β=-0.80 (95% CI -0.10 to -0.01)) and Skeletal Muscle Index (SMI) was negatively associated with WOMAC-F scores (β=-0.16 (95% CI -0.66 to -0.03)). In patients with KOA and obesity, SMI was negatively associated with FTSST (β=-0.30 (95% CI -3.94 to -0.00)).

CONCLUSION

Patients with KOA and obesity had worse knee pain and self-reported function compared with non-obese patients. Greater fat mass, lower muscle mass and lower moderate-intensity to low-intensity physical activity were associated with increased knee pain and poor self-reported function. More skeletal muscle mass was associated with the improvement of objective function.

Pathogenic Mechanisms and Therapeutic Approaches in Obesity-Related Knee Osteoarthritis

The knee is the joint most frequently involved in osteoarthritis, a common joint disorder in the adult population that is associated with significant chronic joint pain, reduced mobility and quality of life. Recent studies have established an association between obesity and the development of knee osteoarthritis that goes beyond the increased mechanical load on the knees as weight-bearing joints. This link is based on the maintenance of a chronic low-grade inflammation, altered secretion of adipokines by the adipose tissue and development of sarcopenia. Major adipokines involved in the pathogenesis of obesity-related knee osteoarthritis include adiponectin, which appears to have a protective effect, as well as leptin, resistin and visfatin, which are associated with higher pain scores and more severe structural damage. Joint pain in knee osteoarthritis may be both nociceptive and neuropathic and is the result of complex mechanisms driven by nerve growth factor, calcitonin gene-related peptide and pro-inflammatory cytokines. The role of endogenous cannabinoids and gut microbiota in common mechanisms between obesity and knee pain has recently been studied. The aim of the present review is to highlight major pathogenic mechanisms in obesity-related knee osteoarthritis with special attention on pain and to comment on possible therapeutic approaches.

Pathological progress and remission strategies of osteoarthritic lesions caused by long-term joint immobilization

OBJECTIVE

While joint immobilization is a useful repair method for intra-articular ligament injury and periarticular fracture, prolonged joint immobilization can cause multiple complications. A better understanding how joint immobilization and remobilization impact joint function and homeostasis will help clinicians develop novel strategies to reduce complications.

DESIGN

We first determined the effects of long-term immobilization on joint pain and osteophyte formation in patients after an extraarticular fracture or ligament injury. We then developed a mouse model of joint immobilization and harvested the knee joint samples at 2, 4, and 8 weeks. We further determined the effects of remobilization on recovery of the osteoarthritis (OA) lesions induced by immobilization in mice.

RESULTS

We found that the long-term (6 weeks) joint immobilization caused significant joint pain and osteophytes in patients. In mice, 2-week immobilization already induced moderate sensory innervation and increased pain sensitivity and infiltration in synovium without inducing marked osteophyte formation and cartilage loss. Long-term immobilization (4 and 8 weeks) induced more severe sensory innervation and inflammatory infiltration in synovium, massive osteophyte formation on both sides of the femoral condyle, and the edge of the tibial plateau and significant loss of the articular cartilage in mice. Remobilization, which ameliorates normal joint load and activity, restored to certain extent some of the OA lesions and joint function in mice.

CONCLUSIONS

Joint immobilization caused multiple OA-like lesions in both mice and humans. Joint immobilization induced progressive sensory innervation, synovitis, osteophyte formation, and cartilage loss in mice, which can be partially ameliorated by remobilization.

Effect of knee osteoarthritis on the postoperative outcome of proximal femoral nail anti-rotation in the treatment of intertrochanteric fractures in the elderly: a retrospective analysis

BACKGROUND

The proximal femoral nail anti-rotation (PFNA) is a commonly used internal fixation system for intertrochanteric fractures (IFs) in older adults. Knee osteoarthritis (KOA) is a degenerative lower extremity disease that occurs most frequently in the elderly. Some patients have already had KOA before the IFs. However, whether KOA impacts the postoperative outcome of IFs has not been reported.

OBJECTIVE

This study aimed to investigate the effect of KOA on the fracture side on the outcome after PFNA for IFs in the elderly.

METHODS

Between January 2016 and November 2021, 297 elderly patients treated with PFNA for IFs were enrolled in this study. They were divided into two groups according to the American Rheumatism Association KOA clinical and radiographic criteria: the control group and the KOA group. Intraoperative bleeding, operative time, length of hospital stay, postoperative time out of bed, fracture healing time, postoperative complications, postoperative Harris hip function score, and Barthel ability to daily living Score were compared between the two groups. Follow-up was routinely scheduled at 1, 3, 6, and 12 months postoperatively.

RESULTS

Based on the exclusion criteria, 254 patients who met the requirements were left to be included in this study, including the control group (n = 133) and the KOA group (n = 121). Patients were followed up for a mean of 17.5 months (12-24 months). There was no significant difference between the two groups in preoperative demographic data, intraoperative blood loss, operation time, and length of stay in the hospital. The control group was statistically significant compared to the KOA group in terms of postoperative time out of bed (17.8 ± 4.0 days vs. 19.1 ± 5.8 days), fracture healing time (13.7 ± 2.2 weeks vs. 14.6 ± 3.7 weeks), and postoperative complications (12.8 vs. 23.1%). The Harris hip function score and Barthel ability to daily living score were higher in the control group than in the KOA group at 1, 3, 6, and 12 months postoperatively (the control group: 63.8 ± 10.9, 71.8 ± 10.3, 81.5 ± 8.7, and 91.6 ± 6.3 vs. The KOA group 61.0 ± 10.4, 68.6 ± 9.1, 79.0 ± 9.2, and 88.5 ± 5.9).

CONCLUSIONS

In elderly patients with IFs combined with KOA of the fracture side treated with PFNA internal fixation, KOA increases the incidence of postoperative complications of the fracture, prolongs postoperative time out of bed and fracture healing, and reduces postoperative hip function and ability to daily living. Therefore, treating KOA on the fractured side needs to be considered when treating IFs in the elderly.

Older age and the presence of intrameniscal signs are risk factors for nonsurgical treatment failure of symptomatic intact discoid lateral meniscus

PURPOSE

The treatment for symptomatic intact discoid lateral meniscus (DLM) is controversial and the long-term clinical outcome remains unknown. The purpose of this study was to analyze the overall failure rate of nonsurgical treatment for symptomatic intact DLM and identify the risk factors for nonoperative management failure.

METHODS

Consecutive patients who underwent nonsurgical treatment for symptomatic intact DLM at our hospital from 2014 to 2017 were retrospectively reviewed. Patients were divided into Group A (failure group) and Group B (nonfailure group) based on overall failure criteria: conversion to surgery, progression of a tear on MRI re-examination, or severely abnormal International Knee Documentation Committee (IKDC) scores. Statistical analyses between the two groups were performed for demographic and radiographic characteristics. Multivariate regression analysis was used to determine the risk factors associated with worse outcomes.

RESULTS

One-hundred and four knees in 96 patients were included in this study. After a mean follow-up of 76.9 ± 11.1 months, 25 knees (24.0%) met the overall failure criteria. Multivariate regression analysis demonstrated that age and the presence of intrameniscus signals increased the risk of nonoperative management failure. The clinical criterion of age > 37.5 years combined with the imaging criterion of the presence of intrameniscal signals predicted conservative treatment failure of symptomatic intact DLM with a sensitivity of 0.87 and a specificity of 0.91.

CONCLUSION

Twenty-five (24.0%) knees that underwent nonsurgical treatment met the overall failure criteria after a mean follow-up of 76.9 months. With increased age and the presence of intrameniscal signals, the nonoperative results become worse.

LEVEL OF EVIDENCE

III.

Xanthohumol alleviates palmitate-induced inflammation and prevents osteoarthritis progression by attenuating mitochondria dysfunction/NLRP3 inflammasome axis

Osteoarthritis (OA) is a prevalent chronic degenerative joint disease worldwide. Obesity has been linked to OA, and increased free fatty acid levels (e.g., palmitate) contribute to inflammatory responses and cartilage degradation. Xanthohumol (Xn), a bioactive prenylated chalcone, was shown to exhibit antioxidative, anti-inflammatory, and anti-obesity capacities in multiple diseases. However, a clear description of the preventive effects of Xn on obesity-associated OA is unavailable. This study aimed to assess the chondroprotective function of Xn on obesity-related OA. The in vitro levels of inflammatory and ECM matrix markers in human chondrocytes were assessed after the chondrocytes were treated with PA and Xn. Additionally, in vivo cartilage degeneration was assessed following oral administration of HFD and Xn. This study found that Xn treatment completely reduces the inflammation and extracellular matrix degradation caused by PA. The proposed mechanism involves AMPK signaling pathway activation by Xn, which increases mitochondrial biogenesis, attenuates mitochondrial dysfunction, and inhibits NLRP3 inflammasome and the NF-κB signaling pathway induced by PA. In summary, this study highlights that Xn could decrease inflammation reactions and the degradation of the cartilage matrix induced by PA by inhibiting the NLRP3 inflammasome and attenuating mitochondria dysfunction in human chondrocytes.

Biomechanical analysis of wood processing work in tropical forest regions: A study in Midwest Brazil

In the wood processing industry, working with machines exposes workers to occupational risks. This study evaluates the biomechanics of work activities carried out in a wood processing operation in tropical forest regions to identify risks associated with the development of musculoskeletal injuries. Data were collected in a wood processing industry from a tropical forest region in Midwest Brazil. Forty forest workers were evaluated, equivalent to 100% of the population of the company participating in the study. Biomechanical movements were measured using the Three-Dimensional Biomechanical Model for Predicting Stances and Static Forces. There was a risk of injury to the joints of the upper limbs (wrists and shoulders), as well as to the torso. When splitting and manually stacking wood, a risk of spinal injury was identified. All workers had a high risk of developing injuries in all joints evaluated in addition to a risk of serious spinal injury. In this way, the development of these activities without any ergonomic interventions makes the risk of developing musculoskeletal injuries in the workers involved imminent, with consequent early professional incapacity.

The Medical Burden of Obesity and Overweight in the US Military: Association of BMI with Clinically Diagnosed Medical Conditions in United States Military Service Members

BACKGROUND

A high BMI is associated with various medical conditions, notably type 2 diabetes, cardiovascular disease, and mental health disorders. In the US military, BMI increased linearly between 1975 and 2015.

OBJECTIVE

This cross-sectional study investigated the associations between BMI and a comprehensive range of clinically diagnosed medical conditions (CDMCs) in US military service members (SMs).

METHODS

A stratified random sample of SMs (n=26,177) completed an online questionnaire reporting their height, weight, and demographic/lifestyle characteristics. Medical conditions for 6 mo before questionnaire completion were obtained from a comprehensive military electronic medical surveillance system and grouped into 39 CDMCs covering both broad (largely systemic) and specific medical conditions. BMI was calculated as weight/height2 (kg/m2). The prevalence of CDMCs was compared among normal weight (<25.0 kg/m2), overweight (25.0-29.9 kg/m2), and obese (≥30 kg/m2) SMs.

RESULTS

After multivariable adjustment for demographic/lifestyle characteristics, higher BMI was associated with higher odds of a diagnosed medical condition in 30 of 39 CDMCs, with all 30 displaying dose-response relationships. The 5 major CDMCs with the largest odds ratios comparing obese to normal weight were endocrine/nutritional/metabolic diseases (OR=2.67, 95%CI=2.24-3.15), nervous system diseases (odds ratio [OR]=2.59, 95%CI=2.32-2.90), circulatory system diseases (OR=2.56, 95%CI=2.15-3.06), musculoskeletal system diseases (OR=1.92, 95%CI=1.76-2.09), and mental/behavioral disorders (OR=1.69, 95%CI=1.51-1.90). Compared with normal weight SMs, overweight or obese SMs had a higher number of CDMCs (1.8±1.9 vs. 2.0±2.0 and 2.5±2.3, mean ± standard deviation, respectively, P<0.01).

CONCLUSIONS

In a young, physically active population, higher BMI was associated with a host of medical conditions, even after adjustment for demographic/lifestyle characteristics. The US Department of Defense should improve nutrition education and modify other factors that contribute to overweight and obesity. This study demonstrates that the medical burden of obesity is substantial in overweight and obese SMs.

Differences Between Patients With Diabetes Mellitus and Obese Patients in Occurrence of Peri-Prosthetic Joint Infection: A Systemic Review and Meta-Analysis

Background: To understand the differences between patients with diabetes mellitus and obese patients with respect to the occurrence of peri-prosthetic joint infection (PJI) after lower-extremity joint arthroplasty as well as to identify differences in PJI occurrence at different time periods. Patients and Methods: The Cochrane Library, CINAHL, MEDLINE, and PubMed were searched for literature published between January 2000 and July 2022. Our targets were studies involving patients with PJI who had already been diagnosed as having diabetes mellitus or being obese before receiving lower-extremity joint arthroplasty. Analysis was performed using Comprehensive Meta-Analysis Software (CMA) Version 3 (Biostat, Inc., Englewood, NJ, USA). Results: A total of 53,522 patients with diabetes mellitus and 360,018 obese patients were included. The forest plot for patients with and without diabetes mellitus indicated that patients with diabetes mellitus were more likely to contract PJIs than were patients without diabetes mellitus (odds ratio, 1.84; 95% confidence interval [CI], 1.56-2.16) and that no differences existed among early, delayed, and late PJI occurrence in patients with diabetes mellitus. The forest plot for obese and non-obese patients indicated that obese patients were more likely to contract PJIs than were non-obese patients (odds ratio, 1.86; 95% CI, 1.53-2.14) and that among obese patients, early PJI occurrence was higher than was late PJI occurrence. In addition, the mixed model indicated that obese patients were more likely to develop early PJIs than were patients with diabetes mellitus. Conclusions: Patients with diabetes mellitus and obese patients were more likely to develop PJIs than were patients without diabetes mellitus and non-obese patients, and that obese patients were more likely to develop early PJIs than late PJIs. Also, obese patients were more likely to develop early PJIs than patients with diabetes mellitus.

'Obesity and arthritis' as the morbid duo: Designing and experimenting a novel strategy for weight reduction at a secondary care ayurveda -arthritis center

Obesity has been a critical confounding factor in arthritis. Its impacts are seemingly more apparent in conditions like knee osteoarthritis but it affects the net outcome in almost every type of arthritis. Reduction of weight is the obvious first advice by a treating physician in such cases. In the absence of a clear roadmap however to reach the goal, It remains an unmet advise for most arthritis patients. Obesity combined with arthritis, becomes a morbid combination where addition of weight adds to intensity of arthritis and arthritis induced limitation of movements adds to the weight. Weight reduction is much tougher in arthritis due to the physical limitations. Noticing this gap of knowledge between desired and achieved, Ayurveda -arthritis treatment and advanced research center at Lucknow has designed a strategic plan as a real help to such people and executed it through the activities focusing upon educating the obese arthritis patients for causes and concerns of obesity in general and individualized management plan through an interactive workshop. A workshop of its own kind was conducted on 24 April 2022. 28 obese arthritics as participants had offered to understand the real need and feasibility of doing these strategically focused activities aiming at weight reduction. This has come up as a new opportunity of help to the obese arthritis patients by empowering them with practical knowledge and tools to reduce weight suiting to their individual capacities and needs. The feedback of the participants provided at the end of the workshop was highly encouraging and has shown that strategically focused activities to bridge the gaps in clinical practice are highly desired and useful.

Obesity, Metabolic Syndrome, and Osteoarthritis-An Updated Review

PURPOSE OF REVIEW

Metabolic syndrome (MetS), also called the 'deadly quartet' comprising obesity, diabetes, dyslipidemia, and hypertension, has been ascertained to have a causal role in the pathogenesis of osteoarthritis (OA). This review is aimed at discussing the current knowledge on the contribution of metabolic syndrome and its various components to OA pathogenesis and progression.

RECENT FINDINGS

Lately, an increased association identified between the various components of metabolic syndrome (obesity, diabetes, dyslipidemia, and hypertension) with OA has led to the identification of the 'metabolic phenotype' of OA. These metabolic perturbations alongside low-grade systemic inflammation have been identified to inflict detrimental effects upon multiple tissues of the joint including cartilage, bone, and synovium leading to complete joint failure in OA. Recent epidemiological and clinical findings affirm that adipokines significantly contribute to inflammation, tissue degradation, and OA pathogenesis mediated through multiple signaling pathways. OA is no longer perceived as just a 'wear and tear' disease and the involvement of the metabolic components in OA pathogenesis adds up to the complexity of the disease. Given the global surge in obesity and its allied metabolic perturbations, this review aims to throw light on the current knowledge on the pathophysiology of MetS-associated OA and the need to address MetS in the context of metabolic OA management. Better regulation of the constituent factors of MetS could be profitable in preventing MetS-associated OA. The identification of key roles for several metabolic regulators in OA pathogenesis has also opened up newer avenues in the recognition and development of novel therapeutic agents.

MATN3 delivered by exosome from synovial mesenchymal stem cells relieves knee osteoarthritis: Evidence from in vitro and in vivo studies

Background

Synovial mesenchymal stem cell (SMSC) exerts chondroprotective effects in osteoarthritis (OA) clinical models. However, the regulatory potentials of SMSC-derived exosomes (SMSC-Exo) in OA still need to be discovered, which attracted our attention.

Methods

The destabilization of the medial meniscus surgery was performed on the knee joints of a mouse OA model, followed by injection of SMSC-Exo. In addition, SMSC-Exo was administrated to mouse chondrocytes to observe the functional and molecular alterations.

Results

Both of SMSC-Exo and overexpression of Matrilin-3 (MATN3) alleviated cartilage destruction and suppressed degradation of extracellular matrix (ECM) in the OA rat model. In addition, assays concerning the in vitro OA model induced by IL-1β showed that SMSC-Exo could promote chondrocyte viability and inhibit autophagy defects. Furthermore, SMSC-Exo achieved the chondroprotective effects through the delivery of MATN3/IL-17A, and MATN3 could suppress the activation of PI3K/AKT/mTOR signaling through IL-17A.

Conclusion

SMSC-Exo exerts beneficial therapeutic effects on OA by preventing ECM degradation and autophagy defects by delivering MATN3/IL-17A.

The Translational Potential of this Article

The translational potential of this study is not only limited to the treatment of knee osteoarthritis but also provides new insights for the treatment of other joint diseases by exploring the mechanism of MATN3. In addition, SMSCExo, as a novel drug carrier, has great potential for treating and diagnosing other diseases. With further research, these findings will provide new directions for developing personalized and innovative treatment options.

Targeting the Inflammatory Hallmarks of Obesity-Associated Osteoarthritis: Towards Nutraceutical-Oriented Preventive and Complementary Therapeutic Strategies Based on n-3 Polyunsaturated Fatty Acids

Obesity (Ob), which has dramatically increased in the last decade, is one of the main risk factors that contribute to the incidence and progression of osteoarthritis (OA). Targeting the characteristics of obesity-associated osteoarthritis (ObOA) may offer new chances for precision medicine strategies in this patient cohort. First, this review outlines how the medical perspective of ObOA has shifted from a focus on biomechanics to the significant contribution of inflammation, mainly mediated by changes in the adipose tissue metabolism through the release of adipokines and the modification of fatty acid (FA) compositions in joint tissues. Preclinical and clinical studies on n-3 polyunsaturated FAs (PUFAs) are critically reviewed to outline the strengths and weaknesses of n-3 PUFAs' role in alleviating inflammatory, catabolic and painful processes. Emphasis is placed on potential preventive and therapeutic nutritional strategies based on n-3 PUFAs, with a focus on ObOA patients who could specifically benefit from reformulating the dietary composition of FAs towards a protective phenotype. Finally, tissue engineering approaches that involve the delivery of n-3 PUFAs directly into the joint are explored to address the perspectives and current limitations, such as safety and stability issues, for implementing preventive and therapeutic strategies based on dietary compounds in ObOA patients.

Tactile acuity and left/right judgment performance in patients with knee osteoarthritis: A cross-sectional study

BACKGROUND

Left/right judgment task (LRJT) performance and tactile acuity are impaired in chronic pain conditions, however, evidence is limited for knee osteoarthritis (OA).

OBJECTIVE

To compare LRJT performance and the two-point discrimination threshold (TPDT) of chronic knee OA patients with asymptomatic knee and pain-free controls.

DESIGN

Cross-sectional study.

METHODS

Fifty knee OA patients and 50 age and gender-matched pain-free controls were assessed using the Recognize® application by displaying knee images and a digital caliper for the TPDT of the medial and lateral knee joint line.

RESULTS

TPDTs over the lateral joint line in symptomatic (mean difference [MD]: 13.59 mm; 95% confidence interval [CI]: 8.72, 18.46; d = 1.40) and asymptomatic knee (MD: 10.15 mm; 95% CI: 5.08, 15.22; d = 0.99) were significantly increased compared to pain-free controls. Similarly, TPDTs of the medial joint line were significantly increased in symptomatic (MD: 12.19 mm; 95% CI: 7.59, 16.79; d = 1.31) and asymptomatic knee (MD: 7.64 mm; 95% CI: 3.64, 11.64; d = 1.31) compared to pain-free controls. Patients with knee OA were less accurate (MD: 7.80%; 95% CI: 15.32, -0.27; d = 0.52) recognizing images of their symptomatic knee. No correlation was found between pain severity, pain duration, LRJT performance, and TPDTs. Post-hoc analysis revealed no differences in LRJT and TPDTs between patients with and without clinically relevant symptoms of central sensitization.

CONCLUSION

Chronic knee OA is associated with increased TPDT for medial and lateral knee joint lines and decreased recognition accuracy performance which should be considered during treatment process.

Prognostic Factors for the Clinical Outcome after Microfracture Treatment of Chondral and Osteochondral Defects in the Knee Joint: A Systematic Review

OBJECTIVE

The objective of this study is to establish which patient and lesion characteristics are related to the clinical outcome after microfracture of cartilage defects in the knee.

STUDY DESIGN

Systematic review.

METHODS

After preregistration, PubMed, Embase, and Cochrane were searched for studies that analyzed prognostic factors for the outcome of microfracture treatment in the knee. The criteria for inclusion were outcome measured using Patient-Reported Outcome Measures (PROMs), a clinical study with ≥10 participants receiving microfracture, and a minimal follow-up period of 1 year.

RESULTS

For none of the investigated prognostic factors, effect size reporting was sufficiently homogeneous to conduct a meta-analysis. However, a majority of the included studies identified higher age, larger lesion size, longer preoperative symptom duration, and previous surgery on the ipsilateral knee, especially meniscectomy and anterior cruciate ligament reconstruction, as factors that are reported to be correlated to a less favorable outcome. A lesion location that does not include the trochlea or the patellofemoral joint and is not weightbearing, a nondegenerative mechanism of injury, and a single lesion were reported as factors that predict a favorable outcome. As to gender, body mass index, preoperative activity level, smoking, and concomitant knee surgery, the included articles were inconclusive or no effect was reported.

CONCLUSIONS

Several factors correlated with the clinical result after microfracture treatment. However, the information on the effect sizes of the influence on clinical outcome is incomplete due to poor reporting. Large-scale registries or pooling of homogeneous, well-reported data is needed to work toward prognostic models. That would be an important step toward personalized treatment.

An investigation on tribological behavior of methacrylated κ-carrageenan and gellan gum hydrogels as a candidate for chondral repair

Natural polysaccharides have recently attracted attention as structural biomaterials to replace focal chondral defects. In the present study, in-vitro tribological performance of methacrylated κ-carrageenan and gellan gum hydrogels (KA-MA and GG-MA) was evaluated under physiological conditions. Coefficient of friction (COF) was continuously recorded over testing whilst worn area was measured post-testing. The findings help improve our understanding of KA-MA-H and GG-MA-H tribological performance under various physiological conditions. The friction and wear performance of the hydrogels improved in bovine calf serum lubricant at lower applied loads. Adhesion was the dominant wear mechanism detected by SEM. Among the proposed hydrogels GG-MA-H found robust mechanical properties, increased wear resistance and considerably low COF, which may suggest its potential usage as a cartilage substitute.

The role of the therapeutic physical exercise and the complex recovery treatment for the patients with chronic degenerative diseases during the COVID-19 pandemic

Abstract: Background: Osteoarthritis is one of the most common causes of pain and musculoskeletal disability and mainly affects the middle-aged and the elderly. The condition is chronic and disabling, it diminishes the patients' quality of life. Purpose. The study had the purpose of pointing out a possible connection between physical ac-tivity and the reduction of pain accompanied by the increased functional capacity in patients with chronic degenerative diseases during the COVID-19 pandemic. Material and method: The study was conducted on an outpatient basis for a period of 6 months on a number of 40 patients diagnosed with osteoarthritis. The evaluation of the pa-tients was made at the beginning of the treatment and at its end (after 4 weeks), as well as at the control after 12 weeks. Results: The study included a number of 40 patients over 45 years old, divided into 2 study groups: in group L1-knee osteoarthritis and in group L2 -hip osteoarthritis. The therapeutic physical exercise reduced pain and stiff-ness, and it also improved the functional capacity. Conclusions: Therapeutic physical exercise has an important role in the reduction of pain and disability, as well as in the increase in the quality of life, if it is done properly. Keywords: osteoarthritis, therapeutic physical exercise, pain, pandemic COVID-19

Deciphering postnatal limb development at single-cell resolution

The early postnatal limb developmental progression bridges embryonic and mature stages and mirrors the pathological remodeling of articular cartilage. However, compared with multitudinous research on embryonic limb development, the early postnatal stage seems relatively unnoticed. Here, a systematic work to portray the postnatal limb developmental landscape was carried out by characterization of 19,952 single cells from murine hindlimbs at 4 postnatal stages using single-cell RNA sequencing technique. By delineation of cell heterogeneity, the candidate progenitor sub-clusters marked by Cd34 and Ly6e were discovered in articular cartilage and enthesis, and three cellular developmental branches marked by Col10a1, Spp1, and Tnni2 were reflected in growth plate. The representative transcriptomes and developmental patterns were intensively explored, and the key regulation mechanisms as well as evolvement in osteoarthritis were discussed. Above all, these results expand horizons of postnatal limb developmental biology and reach the interconnections between limb development, remodeling, and regeneration.

Localization and Likelihood of Chondral and Osteochondral Lesions After Patellar Dislocation in Surgically Treated Children and Adolescents

Background

Patellar dislocation is a common injury in children and adolescents. There is a lack of information about concomitant osteochondral lesions in these patients.

Hypothesis

We hypothesized that the likelihood of chondral or osteochondral lesions would increase with each prior patellar dislocation and that the appearance of lesions in surgically treated children and adolescents would be influenced by age, sex, injury mechanism, and body mass index (BMI).

Study Design

Case-control study; Level of evidence, 3.

Methods

Inclusion criteria were (1) age <18 years, (2) surgical treatment with diagnostic arthroscopy of the knee including description of chondral and osteochondral lesions, and (3) maximum time period between the last patellar dislocation and presentation in our department of 6 weeks and maximum of 4 weeks between presentation and surgery. A total of 153 children (173 knees) with a mean age of 13.0 ± 2.1 years were included. All surgical reports and intraoperative arthroscopic imaging were analyzed retrospectively for the location and severity of lesions. The likelihood of lesions was calculated with multiple stepwise regression models regarding injury mechanism, number of dislocations, sex, age, physeal closure, and BMI.

Results

The regression model to predict femoral lesions was statistically significant (χ²[5] = 26.55; P < .001) and identified male sex, BMI ≥25, traumatic injury mechanism, and physeal closure as independent factors associated with the appearance of femoral lesions. The second regression model predicting the appearance of patellar lesions was also statistically significant (χ²[4] = 26.07; P < .001) and identified the traumatic injury mechanism as a single independent predictor for patellar lesions.

Conclusion

BMI ≥25, male sex, and physeal closure were factors significantly associated with femoral chondral and osteochondral lesions in our cohort. In case of traumatic lateral patellar dislocation (LPD), the likelihood of patellar and femoral chondral and osteochondral lesions is significantly higher than in nontraumatic LPD. Early magnetic resonance imaging and surgical treatment should be considered in obese patients, male patients, and patients with physeal closure and after traumatic LPD.

Current understanding of osteoarthritis pathogenesis and relevant new approaches

Osteoarthritis (OA) is the most common degenerative joint disease that causes painful swelling and permanent damage to the joints in the body. The molecular mechanisms of OA are currently unknown. OA is a heterogeneous disease that affects the entire joint, and multiple tissues are altered during OA development. To better understand the pathological mechanisms of OA, new approaches, methods, and techniques need to be used to understand OA pathogenesis. In this review, we first focus on the epigenetic regulation of OA, with a particular focus on DNA methylation, histone modification, and microRNA regulation, followed by a summary of several key mediators in OA-associated pain. We then introduce several innovative techniques that have been and will continue to be used in the fields of OA and OA-associated pain, such as CRISPR, scRNA sequencing, and lineage tracing. Next, we discuss the timely updates concerning cell death regulation in OA pathology, including pyroptosis, ferroptosis, and autophagy, as well as their individual roles in OA and potential molecular targets in treating OA. Finally, our review highlights new directions on the role of the synovial lymphatic system in OA. An improved understanding of OA pathogenesis will aid in the development of more specific and effective therapeutic interventions for OA.

The effects and significance of gut microbiota and its metabolites on the regulation of osteoarthritis: Close coordination of gut-bone axis

Osteoarthritis (OA) is a common chronic degenerative disease of articular cartilage in middle-aged and older individuals, which can result in the joint pain and dysfunction, and even cause the joint deformity or disability. With the enhancing process of global aging, OA has gradually become a major public health problem worldwide. Explaining pathogenesis of OA is critical for the development of new preventive and therapeutic interventions. In recent years, gut microbiota (GM) has been generally regarded as a “multifunctional organ,” which is closely relevant with a variety of immune, metabolic and inflammatory functions. Meanwhile, more and more human and animal researches have indicated the existence of gut-bone axis and suggested that GM and its metabolites are closely involved in the pathogenic process of OA, which might become a potential and promising intervention target. Based on the close coordination of gut-bone axis, this review aims to summarize and discuss the mechanisms of GM and its metabolites influencing OA from the aspects of the intestinal mucosal barrier modulation, intestinal metabolites modulation, immune modulation and strategies for the prevention or treatment of OA based on perspectives of GM and its metabolites, thus providing a profound knowledge and recognition of it.

The burden of end-stage osteoarthritis in Australia: a population-based study on the incidence of total knee replacement attributable to overweight/obesity

OBJECTIVES

To determine the risk of total knee replacement (TKR) for primary osteoarthritis (OA) associated with overweight/obesity in the Australian population.

METHODS

This population-based study analyzed 191,723 cases of TKR collected by the Australian Orthopaedic Association National Joint Registry and population data from the Australian Bureau of Statistics. The time-trend change in incidence of TKR relating to BMI was assessed between 2015 and 2018. The influence of obesity on the incidence of TKR in different age and gender groups was determined. The population attributable fraction (PAF) was then calculated to estimate the effect of obesity reduction on TKR incidence.

RESULTS

The greatest increase in incidence of TKR was seen in patients from obese class III. The incidence rate ratio for having a TKR for obesity class III was 28.683 at those aged 18-54 years but was 2.029 at those aged >75 years. Females in obesity class III were 1.7 times more likely to undergo TKR compared to similarly classified males. The PAFs of TKR associated with overweight or obesity was 35%, estimating 14,287 cases of TKR attributable to obesity in 2018. The proportion of TKRs could be reduced by 20% if overweight and obese population move down one category.

CONCLUSIONS

Obesity has resulted in a significant increase in the incidence of TKR in the youngest population in Australia. The impact of obesity is greatest in the young and the female population. Effective strategies to reduce the national obese population could potentially reduce 35% of the TKR, with over 10,000 cases being avoided.

The efficacy and safety of Jinwu Gutong capsule in the treatment of knee osteoarthritis: A meta-analysis of randomized controlled trials

ETHNOPHARMACOLOGICAL RELEVANCE

The Jinwu Gutong (JWGT) capsule is a Chinese patent medicine that is widely used in the treatment of knee osteoarthritis (KOA) and osteoporosis in China and is considered to have the potential for good clinical efficacy.

AIM OF THE STUDY

The purpose of this study was to systematically evaluate the clinical efficacy and safety of JWGT in the treatment of KOA.

MATERIALS AND METHODS

We searched the China National Knowledge Infrastructure (CNKI), Wanfang, SinoMed, PubMed, Embase and Cochrane Library databases to identify clinical trials that explore the use of JWGT only or JWGT combined with Western drugs (JWGT group) compared with the use of conventional Western drugs (Western drugs group) for the treatment of KOA. The clinical trials, that were retrieved from each database from the inception of the database to December 2021, were screened. We used the risk of bias assessment tool recommended by Cochrane to evaluate the quality of the included literature and RevMan 5.3 software for data analysis.

RESULTS

A total of 17 clinical randomized controlled trials (RCTs) were included in this study, with a total of 1930 participants, including 1015 people in the experimental group and 915 people in the control group. The results of the meta-analysis showed that the JWGT group exhibited better efficacy than the Western drug group with respect to WOMAC score (WMD = -6.25, 95% CI = -8.09 to -4.41, P < 0.001), VAS score (WMD = -1.36, 95% CI = -2.17 to -0.55, P = 0.001), KSS score (WMD = 23.01, 95% CI = 21.42 to 24.59, P < 0.001), IL-6 (SMD = -3.30, 95% CI = -4.84 to -1.76, P < 0.001), TNF-α (SMD = -1.70, 95% CI = -2.02 to -1.38, P < 0.001). The effective rate (OR = 2.56, 95% CI = 1.83 to 3.57, P < 0.001) and incidence of adverse reactions was significantly lower in the JWGT group than in the control group (OR = 0.13, 95% CI = 0.07 to 0.21, P < 0.001). Subgroup analysis showed that JWGT + NSAIDs had more advantages in regard to efficacy (OR = 2.05, 95% CI = 1.35 to 3.12, P < 0.001), and reducing adverse reactions (OR = 0.10, 95% CI = 0.06 to 0.18, P < 0.001), VAS score (WMD = -1.00, 95% CI = -1.93 to -0.07, P = 0.04), KSS score (WMD = 17.39, 95% CI = 15.39 to 19.39, P < 0.001), WOMAC score (WMD = -2.84, 95% CI = -10.75 to 5.08, P < 0.001), IL-6 (SMD = -1.42, 95% CI = -2.08 to -0.75, P < 0.001) and TNF-α (SMD = -1.68, 95% CI = -1.93 to -1.43, P < 0.001) than NSAIDs alone. Compared with hyaluronic acid (HA) alone, JWGT + HA had better clinical efficacy (OR = 3.08, 95% CI = 1.48 to 6.40, P < 0.001). Compared with glucosamine (GS) alone, JWGT + GS significantly reduced the Lequesne index score (WMD = -0.53, 95% CI = -0.85 to -0.21, P = 0.001) and the serum TNF-α level (SMD = -1.68, 95% CI = -1.93 to -1.43, P < 0.001), but it had no significant advantage in reducing the serum IL-6 level (SMD = -4.53, 95% CI = -10.13 to 1.07, P = 0.11).

CONCLUSION

JWGT is considered effective and safe in the treatment of KOA and is worthy of clinical application. In addition, the application of JWGT combined with NSAIDs, HA or GS can significantly improve the clinical efficacy of the latter agents in KOA treatment.

Curcumin exerts chondroprotective effects against osteoarthritis by promoting AMPK/PINK1/Parkin-mediated mitophagy

Osteoarthritis (OA), a chronic degenerative disease with heterogeneous properties, is difficult to cure due to its complex pathogenesis. Curcumin possesses excellent anti-inflammatory and antioxidant properties and may have potential therapeutic value in OA. In this study, we investigated the action targets of curcumin and identified potential anti-OA targets for curcumin. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathway analyses were performed to evaluate these targets. Furthermore, we established a sodium monoiodoacetate-induced rat knee OA model and IL-1β induced OA chondrocyte model to verify the effect and mechanism of curcumin against OA. The GO and KEGG analyses screened seven hub genes involved in metabolic processes and the AMPK signaling pathway. Curcumin can significantly attenuate OA characteristics according to Osteoarthritis Research Society International (OARSI) and Mankin scores in OA rats. Additionally, curcumin is notably employed as an activator of mitophagy in maintaining mitochondrial homeostasis (ROS, Ca²⁺, ATP production, and mitochondrial membrane potential). The expression levels of mitophagy-related proteins were increased not only in articular cartilage but also in chondrocytes with curcumin intervention. Combining validation experiments and network pharmacology, we identified the importance of mitophagy in the curcumin treatment of OA. The chondroprotective effects of curcumin against OA are mediated by the AMPK/PINK1/Parkin pathway, and curcumin may serve as a potential novel drug for OA management.

Instructive cartilage regeneration modalities with advanced therapeutic implantations under abnormal conditions

The development of interdisciplinary biomedical engineering brings significant breakthroughs to the field of cartilage regeneration. However, cartilage defects are considerably more complicated in clinical conditions, especially when injuries occur at specific sites (e.g., osteochondral tissue, growth plate, and weight-bearing area) or under inflammatory microenvironments (e.g., osteoarthritis and rheumatoid arthritis). Therapeutic implantations, including advanced scaffolds, developed growth factors, and various cells alone or in combination currently used to treat cartilage lesions, address cartilage regeneration under abnormal conditions. This review summarizes the strategies for cartilage regeneration at particular sites and pathological microenvironment regulation and discusses the challenges and opportunities for clinical transformation.

Risk factors associated with the occurrence of total knee arthroplasty in patients with knee osteoarthritis: a nested case–control study

Objectives:

The aim of this study was to investigate changes over time in osteoarthritis risk factors most closely associated with the occurrence of total knee arthroplasty (TKA). We hypothesize that the robustness of a longitudinal case–control study will provide new information on the association between changes in various clinical and structural parameters in different time frames before TKA.

Methods:

Cases (195; TKA after cohort entry) and controls (468) matched for age, gender, income, WOMAC pain, Kellgren–Lawrence grade and follow-up duration were from the Osteoarthritis Initiative cohort. Associations between changes in sociodemographic, clinical, imaging and osteoarthritis therapies with the occurrence of TKA were performed using conditional logistic regression analyses.

Results:

Worsening of WOMAC scores (cOR 1.02–1.20, p ⩽ 0.012), KOOS (1.02–1.04, p ⩽ 0.014), knee injuries sustained in the previous 30–40 years (women 2.70, p = 0.034) and valgus alignment (1.10, p = 0.052) were associated with the occurrence of TKA. Also associated with TKA was cartilage volume loss in the lateral (overall 1.76, p = 0.025; women 1.93, p = 0.047) and medial compartments (⩾10%, overall 1.54, p = 0.027; men 2.34, p = 0.008), occurrence of medial meniscal extrusion (overall 1.77, p = 0.046; men 2.86, p = 0.028), and increase in bone marrow lesions (BMLs) for women (1.09, p = 0.048). The association of risk factors with TKA was reinforced when both an increase in WOMAC pain and cartilage volume loss (1.85, p = 0.001) were combined. Pain medication usage, mainly narcotics and intra-articular steroid injections (IASI), was also associated with TKA, with no impact on changes in cartilage loss or structure.

Conclusion:

This study provides new information about gender differences in risk factors associated with the occurrence of TKA. Worsening of valgus alignment, cartilage volume loss in the lateral compartment, BMLs and older injuries are important risk factors in women, while medial compartment cartilage loss and meniscal extrusion are in men. The use of pain medication and IASI although associated was found not causal with TKA.

Clinical significance of serum GPX2 levels in patients with osteoarthritis was suppressed and reduced inflammation of osteoarthritis through STAT3 function

The main alterations of osteoarthritis are degenerative lesions of articular cartilage and secondary hyperostosis. Despite the unclear pathogenic mechanism, experimental studies have confirmed that the incidence of osteoarthritis is closely associated with inflammation-related substances. In this study, we explored the significance of serum GPX2 levels in patients with osteoarthritis and the mechanism of GPX2 in the anti-inflammation effects in osteoarthritis. As a result, serum GPX2 level was down-regulated and there was a negative correlation between GPX2 levels and IL-1β levels in patients with osteoarthritis. Over-expression of GPX2 decreased the inflammatory levels and down-regulation of GPX2 increased inflammatory levels in vitro. In contrast, GPX2 combined and regulated STAT3 protein expression. Over-expression of GPX2 promoted ubiquitination-STAT3 protein expression to decrease p-STAT3 protein expression in vitro. The inhibition of STAT3 attenuated the anti-inflammation effects of GPX2 in osteoarthritis. Thus, we proposed that GPX2 was down-regulated in patients with osteoarthritis and GPX2 played vital roles in osteoarthritis for clinical diagnosis or therapy.

The Association of Blood Biomarkers and Body Mass Index in Knee Osteoarthritis: A Cross-Sectional Study

OBJECTIVE

Despite massive efforts, there are no diagnostic blood biomarkers for knee osteoarthritis (KOA). This study investigated several candidate diagnostic biomarkers and the metabolic phenotype in end-stage KOA in the context of obesity.

DESIGN

In this cross-sectional study, adult patients undergoing knee arthroplasty were enrolled and KOA severity was assessed using the Lequesne index. Blood biomarkers with an important role in obesity, the metabolic syndrome, or KOA (oxidized form of low-density lipoprotein [oxLDL], advanced glycation end product [AGE], soluble AGE receptor [sRAGE], fatty acid binding protein 4 [FABP4], phospholipase A2 group IIA [PLA2G2A], fibroblast growth factor 23 [FGF-23], ghrelin, leptin, and resistin) were measured using enzyme-linked immunosorbent assay (ELISA; n = 70) or Luminex technique (subgroup of n = 35). H1-NMR spectroscopy was used for the quantification of metabolite levels (subgroup of n = 31). The hip-knee-ankle angle was assessed. Multivariable and multivariate regression analysis was used to examine the relationship of biomarkers with body mass index (BMI) and KOA severity in complete case and multiple imputation analysis.

RESULTS

While most of the investigated biomarkers were not associated with KOA severity, FABP4 and leptin were found to correlate with BMI and gender. Resistin was associated with Lequesne index in complete case analysis. Using a targeted metabolomics approach, BMI-dependent changes in the metabolome were hardly visible.

CONCLUSIONS

Our findings confirm studies on FABP4, leptin, and resistin with regard to obesity and the metabolic syndrome. There was no association of the investigated biomarkers with KOA severity, most likely due to the patient selection (end-stage KOA patients). Based on this absence of BMI-dependent changes in the metabolome, we might assume that BMI is not correlated with KOA severity in this specific patient group.

Disease burden of osteoarthritis of the knee and hip due to a high body mass index in China and the USA: 1990-2019 findings from the global burden of disease study 2019

Background

Osteoarthritis (OA) is a leading cause of disability and a source of societal costs among older adults, especially with an increasingly obese population. However, very few published studies have investigated the burden of knee and hip OA due to a high body mass index (BMI). Therefore, this study aimed to systematically summarize the trends of knee and hip OA due to a high BMI in China and the USA between 1990 and 2019.

Methods

Data from the Global Burden of Disease Study 2019 were used to estimate the age-standardized prevalence, disability-adjusted life years (DALYs) rates of knee and hip OA, and the burden of knee and hip OA due to a high BMI by sex. Joinpoint regression analysis was used to determine the temporal trend changes in the related DALYs rates of knee and hip OA.

Results

The trends in the DALYs rates of knee OA due to a high BMI have shown a steady and large increase in China, while the trends first showed an increase followed by a large decrease near 2001-2005 and finally a steady increase in the USA. The trends in the DALYs rates of hip OA due to a high BMI have shown a steady and large increase in both men and women in China and the USA from 1990 to 2019. For the comparison by age categories from 30 to 34 years to 90–94 years in 2019, the age-standardized DALYs rates due to a high BMI first increased and then decreased after 60–64 years and 70-74 years in both men and women from China and the USA for knee OA, respectively. For hip OA, the age-standardized DALYs rates first increased and then decreased after 70–74 years in both men and women from China and the USA.

Conclusions

The burden of knee and hip OA due to a high BMI is substantially increasing in China and the USA in recent years. Researchers and health policy makers should assess the changing patterns of high BMI on the burden of OA and devise corresponding weight-control strategies.

Sprifermin: Effects on Cartilage Homeostasis and Therapeutic Prospects in Cartilage-Related Diseases

When suffering from osteoarthritis (OA), articular cartilage homeostasis is out of balance and the living quality declines. The treatment of knee OA has always been an unsolved problem in the world. At present, symptomatic treatment is mainly adopted for OA. Drug therapy is mainly used to relieve pain symptoms, but often accompanied with adverse reactions; surgical treatment involves the problem of poor integration between the repaired or transplanted tissues and the natural cartilage, leading to the failure of repair. Biotherapy which aims to promote cartilage in situ regeneration and to restore endochondral homeostasis is expected to be an effective method for the prevention and treatment of OA. Disease-modifying osteoarthritis drugs (DMOADs) are intended for targeted treatment of OA. The DMOADs prevent excessive destruction of articular cartilage through anti-catabolism and stimulate tissue regeneration via excitoanabolic effects. Sprifermin (recombinant human FGF18, rhFGF18) is an effective DMOAD, which can not only promote the proliferation of articular chondrocyte and the synthesis of extracellular matrix, increase the thickness of cartilage in a dose-dependent manner, but also inhibit the activity of proteolytic enzymes and remarkedly slow down the degeneration of cartilage. This paper reviews the unique advantages of Sprifermin in repairing cartilage injury and improving cartilage homeostasis, aiming to provide an important strategy for the effective prevention and treatment of cartilage injury-related diseases.

Monocytes, Macrophages, and Their Potential Niches in Synovial Joints - Therapeutic Targets in Post-Traumatic Osteoarthritis?

Synovial joints are complex structures that enable normal locomotion. Following injury, they undergo a series of changes, including a prevalent inflammatory response. This increases the risk for development of osteoarthritis (OA), the most common joint disorder. In healthy joints, macrophages are the predominant immune cells. They regulate bone turnover, constantly scavenge debris from the joint cavity and, together with synovial fibroblasts, form a protective barrier. Macrophages thus work in concert with the non-hematopoietic stroma. In turn, the stroma provides a scaffold as well as molecular signals for macrophage survival and functional imprinting: “a macrophage niche”. These intricate cellular interactions are susceptible to perturbations like those induced by joint injury. With this review, we explore how the concepts of local tissue niches apply to synovial joints. We introduce the joint micro-anatomy and cellular players, and discuss their potential interactions in healthy joints, with an emphasis on molecular cues underlying their crosstalk and relevance to joint functionality. We then consider how these interactions are perturbed by joint injury and how they may contribute to OA pathogenesis. We conclude by discussing how understanding these changes might help identify novel therapeutic avenues with the potential of restoring joint function and reducing post-traumatic OA risk.