Artificial intelligence in osteoarthritis: repair by knee joint distraction shows association of pain, radiographic and immunological outcomes.

OBJECTIVES: Knee joint distraction (KJD) has been associated with clinical and structural improvement and SF marker changes. The current objective was to analyse radiographic changes after KJD using an automatic artificial intelligence-based measurement method and relate these to clinical outcome and SF markers. METHODS: Twenty knee osteoarthritis patients were treated with KJD in regular care. Radiographs and WOMAC were collected before and ∼1 year post-treatment. SF was aspirated before, during and after treatment; biomarker levels were assessed by immunoassay. Radiographs were analysed to obtain compartmental minimum and standardized joint space width (JSW), Kellgren-Lawrence (KL) grades, compartmental joint space narrowing (JSN) scores, and osteophytosis and sclerosis scores. Results were analysed for the most affected compartment (MAC) and least affected compartment. Radiographic changes were analysed using the Wilcoxon signed rank test for categorical and paired t-test for continuous variables. Linear regression was used to calculate associations between changes in JSW, WOMAC pain and SF markers. RESULTS: Sixteen patients could be evaluated. JSW, KL and JSN improved in around half of the patients, significant only for MAC JSW (P < 0.05). MAC JSW change was positively associated with WOMAC pain change (P < 0.04). Greater monocyte chemoattractant protein 1 (MCP-1) and lower TGFß-1 increases were significantly associated with changes in MAC JSW (P < 0.05). MCP-1 changes were positively associated with WOMAC pain changes (P < 0.05). CONCLUSION: Automatic radiographic measurements show improved joint structure in most patients after KJD in regular care. MAC JSW increased significantly and was associated with SF biomarker level changes and even with improvements in pain as experienced by these patients.

Posttraumatic osteoarthritis: what have we learned to advance osteoarthritis?

PURPOSE OF REVIEW: Current thinking in the study of posttraumatic osteoarthritis (PTOA) is overviewed: the osteoarthritis which follows acute joint injury. The review particularly highlights important publications in the last 18 months, also reflecting on key older literature, in terms of what have we have we learned and have yet to learn from PTOA, which can advance the osteoarthritis field as a whole. RECENT FINDINGS: PTOA is a mechanically driven disease, giving insight into mechanical drivers for osteoarthritis. A mechanosensitive molecular tissue injury response (which includes activation of pain, degradative and also repair pathways) is triggered by acute joint injury and seen in osteoarthritis. Imaging features of PTOA are highly similar to osteoarthritis, arguing against it being a different phenotype. The inflammatory pathways activated by injury contribute to early joint symptoms. However, later structural changes appear to be dissociated from traditional measures of synovial inflammation. SUMMARY: PTOA remains an important niche in which to understand processes underlying osteoarthritis and seek interventional targets. Whether PTOA has true molecular or clinical differences to osteoarthritis as a whole remains to be understood. This knowledge is important for a field where animal modelling of the disease relies heavily on the link between injury and osteoarthritis.

Mining the Proteome Associated with Rheumatic and Autoimmune Diseases.

A steady increase in the incidence of osteoarthritis and other rheumatic diseases has been observed in recent decades, including autoimmune conditions such as rheumatoid arthritis, spondyloarthropathies, systemic lupus erythematosus, systemic sclerosis, and Sjögren's syndrome. Rheumatic and autoimmune diseases (RADs) are characterized by the inflammation of joints, muscles, or other connective tissues. In addition to often experiencing debilitating mobility and pain, RAD patients are also at a higher risk of suffering comorbidities such as cardiovascular or infectious events. Given the socioeconomic impact of RADs, broad research efforts have been dedicated to these diseases worldwide. In the present work, we applied literature mining platforms to identify "popular" proteins closely related to RADs. The platform is based on publicly available literature. The results not only will enable the systematic prioritization of candidates to perform targeted proteomics studies but also may lead to a greater insight into the key pathogenic processes of these disorders.

Hydroxychloroquine Effectiveness in Reducing Symptoms of Hand Osteoarthritis: A Randomized Trial.

Background: Synovitis is believed to play a role in producing symptoms in persons with hand osteoarthritis, but data on slow-acting anti-inflammatory treatments are sparse. Objective: To determine the effectiveness of hydroxychloroquine versus placebo as an analgesic treatment of hand osteoarthritis. Design: Randomized, double-blind, placebo-controlled clinical trial with 12-month follow-up. (ISRCTN registry number: ISRCTN91859104). Setting: 13 primary and secondary care centers in England. Participants: Of 316 patients screened, 248 participants (82% women; mean age, 62.7 years) with symptomatic (pain ≥4 on a 0- to 10-point visual analogue scale) and radiographic hand osteoarthritis were randomly assigned and 210 (84.7%) completed the 6-month primary end point. Intervention: Hydroxychloroquine (200 to 400 mg) or placebo (1:1) for 12 months with ongoing usual care. Measurements: The primary end point was average hand pain during the previous 2 weeks (on a 0- to 10-point numerical rating scale [NRS]) at 6 months. Secondary end points included self-reported pain and function, grip strength, quality of life, radiographic structural change, and adverse events. Baseline ultrasonography was done. Results: At 6 months, mean hand pain was 5.49 points in the placebo group and 5.66 points in the hydroxychloroquine group, with a treatment difference of -0.16 point (95% CI, -0.73 to 0.40 point) (P = 0.57). Results were robust to adjustments for adherence, missing data, and use of rescue medication. No significant treatment differences existed at 3, 6, or 12 months for any secondary outcomes. The percentage of participants with at least 1 joint with synovitis was 94% (134 of 143) on grayscale ultrasonography and 59% on power Doppler. Baseline structural damage or synovitis did not affect treatment response. Fifteen serious adverse events were reported (7 in the hydroxychloroquine group [3 defined as possibly related] and 8 in the placebo group). Limitation: Hydroxychloroquine dosage restrictions may have reduced efficacy. Conclusion: Hydroxychloroquine was no more effective than placebo for pain relief in patients with moderate to severe hand pain and radiographic osteoarthritis. Primary Funding Source: Arthritis Research UK.

Harmonising data collection from osteoarthritis studies to enable stratification: recommendations on core data collection from an Arthritis Research UK clinical studies group.

OBJECTIVE: Treatment of OA by stratifying for commonly used and novel therapies will likely improve the range of effective therapy options and their rational deployment in this undertreated, chronic disease. In order to develop appropriate datasets for conducting post hoc analyses to inform approaches to stratification for OA, our aim was to develop recommendations on the minimum data that should be recorded at baseline in all future OA interventional and observational studies. METHODS: An Arthritis Research UK study group comprised of 32 experts used a Delphi-style approach supported by a literature review of systematic reviews to come to a consensus on core data collection for OA studies. RESULTS: Thirty-five systematic reviews were used as the basis for the consensus group discussion. For studies with a primary structural endpoint, core domains for collection were defined as BMI, age, gender, racial origin, comorbidities, baseline OA pain, pain in other joints and occupation. In addition to the items generalizable to all anatomical sites, joint-specific domains included radiographic measures, surgical history and anatomical factors, including alignment. To demonstrate clinical relevance for symptom studies, the collection of mental health score, self-efficacy and depression scales were advised in addition to the above. CONCLUSIONS: Currently it is not possible to stratify patients with OA into therapeutic groups. A list of core and optional data to be collected in all OA interventional and observational studies was developed, providing a basis for future analyses to identify predictors of progression or response to treatment.

Night-time immobilization of the distal interphalangeal joint reduces pain and extension deformity in hand osteoarthritis.

OBJECTIVE: DIP joint OA is common but has few cost-effective, evidence-based interventions. Pain and deformity [radial or ulnar deviation of the joint or loss of full extension (extension lag)] frequently lead to functional and cosmetic issues. We investigated whether splinting the DIP joint would improve pain, function and deformity. METHODS: A prospective, radiologist-blinded, non-randomized, internally controlled trial of custom splinting of the DIP joint was carried out. Twenty-six subjects with painful, deforming DIP joint hand OA gave written, informed consent. One intervention joint and one control joint were nominated. A custom gutter splint was worn nightly for 3 months on the intervention joint, with clinical and radiological assessment at baseline, 3 and 6 months. Differences in the change were compared by the Wilcoxon signed rank test. RESULTS: The median average pain at baseline was similar in the intervention (6/10) and control joints (5/10). Average pain (primary outcome measure) and worst pain in the intervention joint were significantly lower at 3 months compared with baseline (P = 0.002, P = 0.02). Differences between intervention and control joint average pain reached significance at 6 months (P = 0.049). Extension lag deformity was significantly improved in intervention joints at 3 months and in splinted joints compared with matched contralateral joints (P = 0.016). CONCLUSION: Short-term night-time DIP joint splinting is a safe, simple treatment modality that reduces DIP joint pain and improves extension of the digit, and does not appear to give rise to non-compliance, increased stiffness or joint restriction. TRIAL REGISTRATION: clinical trials.gov, http://clinicaltrials.gov, NCT01249391.

Src and fibroblast growth factor 2 independently regulate signaling and gene expression induced by experimental injury to intact articular cartilage.

OBJECTIVE: To investigate whether cartilage injury activates protein tyrosine kinases distinct from fibroblast growth factor (FGF)-related signaling, and whether they contribute to injury-induced gene responses. METHODS: Phosphokinases and protein tyrosine phosphorylation were assayed by Western blotting of cartilage lysates. Immunoprecipitation and Western blotting with 4G10 antibody and immunoprecipitation kinase assay were carried out. Tyrosine-phosphorylated proteins on silver-stained gels of injured cartilage lysates were identified by mass spectrometry. Messenger RNA induction in cartilage explants was assessed by quantitative reverse transcriptase-polymerase chain reaction. RESULTS: Protein tyrosine phosphorylation occurred within seconds of injury to the surface of intact articular cartilage, as did activation of MAPKs and IKK. Activation did not reoccur upon reinjury of cultured explants. The prominent tyrosine-phosphorylated proteins focal adhesion kinase, paxillin, and cortactin were identified as substrates of Src family kinases. The Src family kinase inhibitor PP2 blocked injury-induced tyrosine phosphorylation. It did not prevent activation of the MAPKs and IKK but differentially inhibited 8 of 10 inflammatory response genes that were induced by injury. In contrast, FGF signaling blockade with PD173074 reduced all MAPK and IKK activation by ∼50% and inhibited a different subset of genes but had no effect on Src-like signaling. CONCLUSION: Injury to the surface of intact articular cartilage activates Src-like kinases as well as MAPKs and IKK (implying NF-κB activation). FGF-2 contributes to MAPK/IKK activation but not to Src-like signaling, suggesting that the latter is a parallel pathway that also regulates the injury-induced inflammatory gene response.

Fibroblast growth factor 2 drives changes in gene expression following injury to murine cartilage in vitro and in vivo.

OBJECTIVE: The articular cartilage is known to be highly mechanosensitive, and a number of mechanosensing mechanisms have been proposed as mediators of the cellular responses to altered mechanical load. These pathways are likely to be important in tissue homeostasis as well as in the pathogenesis of osteoarthritis. One important injury-activated pathway involves the release of pericellular fibroblast growth factor 2 (FGF-2) from the articular cartilage. Using a novel model of murine cartilage injury and surgically destabilized joints in mice, we examined the extent to which FGF-2 contributes to the cellular gene response to injury. METHODS: Femoral epiphyses from 5-week-old wild-type mice were avulsed and cultured in serum-free medium. Explant lysates were Western blotted for phospho-JNK, phospho-p38, and phospho-ERK or were fixed for immunohistochemical analysis of the nuclear translocation of p65 (indicative of NF-κB activation). RNA was extracted from injured explants, rested explants that had been stimulated with recombinant FGF-2 or FGF-18, or whole joints from either wild-type mice or FGF-2(-/-) mice. Reverse transcription-polymerase chain reaction was performed to examine a number of inflammatory response genes that had previously been identified in a microarray analysis. RESULTS: Murine cartilage avulsion injury resulted in rapid activation of the 3 MAP kinase pathways as well as NF-κB. Almost all genes identified in murine joints following surgical destabilization were also regulated in cartilage explants upon injury. Many of these genes, including those for activin A (Inhba), tumor necrosis factor-stimulated gene 6 (Tnfaip6), matrix metalloproteinase 19 (Mmp19), tissue inhibitor of metalloproteinases 1 (Timp1), and podoplanin (Pdpn), were significantly FGF-2 dependent following injury to cartilage in vitro and to joint tissues in vivo. CONCLUSION: FGF-2-dependent gene expression occurs in vitro and in vivo in response to cartilage/joint injury in mice.

Could sex-specific subtypes of hand osteoarthritis exist? A retrospective study in women presenting to secondary care.

Introduction: Hand osteoarthritis is more common in women, and its risk increases around the time of the menopause. We set out to describe the timing between menopause and the onset of symptomatic hand osteoarthritis (OA), and associations with the use of hormone replacement therapy (HRT) or its discontinuation, describing any identifiable subgroups of women. Methods: Retrospective healthcare-records study of sequential women referred to a specialist hand OA clinic, 2007-2015. Confirmation of hand OA diagnosis was by clinican, by accepted criteria. Demographics and clinical variables were from healthcare-records, recorded by standardised proforma. Outcomes of interest were reported age of onset of hand symptoms, reported age at final menstrual period (FMP), time from FMP to reported onset of hand symptoms and time from cessation of HRT to reported onset of hand symptoms. Exposure categories for systemic HRT use were never users, current users, previous users. Analysis of Variance compared groups; linear regression analysed associations of exposure with outcome. Results: 82/92(89%) of eligible women were post-menopausal, mean age at FMP 49.9 years (SD5.4). In these post-menopausal women, median time from FMP to hand symptom onset was 3 years. 48/82 (59%) developed hand symptoms within the defined peri-menopausal period (FMP ± 4 years), whilst some women developed their symptoms before or after (range -25, 30 years). In women who discontinued HRT prior to symptom onset, the median time from HRT cessation to onset of hand symptoms was 6 months. Past HRT users were older at hand symptom onset than women who had not taken HRT [coeff.4.7 years (0.92, 8.39); P = 0.015]. Conclusions: This study adds to evidence associating the menopause/sex hormone deficiency with hand OA symptom onset in a sizeable subgroup of women (but not all). HRT use/cessation appears to influence the timing of onset of hand OA symptoms. It is not possible to interpret from this type of study whether sex hormone deficiency is causative of disease or modulates its symptoms. It is also not possible to judge whether painful hand osteoarthritis in post-menopausal women is a subtype of disease. Further investigation is indicated of sex-specific subtypes and potential for personalised medicine for post-menopausal women with hand osteoarthritis, as a clearly definable high-risk subgroup.

The Effect of Acute Knee Injuries and Related Knee Surgery on Serum Levels of Pro- and Anti-inflammatory Lipid Mediators and Their Associations With Knee Symptoms.

BACKGROUND: Despite an acute knee injury being a major risk factor for osteoarthritis, the factors that initiate and maintain this risk of longer-term knee symptoms are poorly understood. Bioactive lipids derived from omega-3 and -6 polyunsaturated fatty acids have key roles in the regulation of the inflammatory response and have been linked to joint damage and osteoarthritis pain in translational models. HYPOTHESIS: There would be associations between systemic levels of bioactive lipids and knee symptoms longitudinally after an acute knee injury and related knee surgery. STUDY DESIGN: Controlled laboratory study. METHODS: This study analyzed a subset of young, active adults who had sustained an acute knee injury (recruited via a surgical care pathway) and healthy age- and sex-matched controls. Surgery, if performed, was conducted after the baseline serum sample was taken and before the 3-month and 2-year visits. Liquid chromatography-tandem mass spectrometry of 41 bioactive lipids was carried out in sera of (1) 47 injured participants (median age, 28 years) collected at baseline (median, 24 days after injury), 3 months, and 2 years, along with the Knee injury and Osteoarthritis Outcome Score, and (2) age- and sex-matched controls. RESULTS: Levels of the omega-3 polyunsaturated fatty acids eicosapentaenoic acid (P≤ .0001) and docosahexaenoic acid (P≤ .0001) and the pro-resolving lipid mediators 17- and 14-hydroxydocosahexaenoic acid, and 18-hydroxyeicosapentaenoic acid were all significantly greater at baseline in injured participants compared with the later time points and also higher than in healthy controls (P = .0019 and P≤ .0001, respectively). Levels of pro-inflammatory prostaglandins E2 and D2, leukotriene B4, and thromboxane B2 were significantly lower at baseline compared with the later time points. Higher levels of 8,9-, 11,12-, and 14,15-dihydroxyeicosatrienoic acid (DHET) were cross-sectionally associated with more severe knee pain/symptoms according to the Knee injury and Osteoarthritis Outcome Score at 2 years (P = .0004, R2 = 0.251; P = .0002, R2 = 0.278; and P = .0012, R2 = 0.214, respectively). CONCLUSION: The profile of pro-resolving versus pro-inflammatory lipids at baseline suggests an initial activation of pro-resolution pathways, followed by the later activation of pro-inflammatory pathways. CLINICAL RELEVANCE: In this largely surgically managed cohort, the association of soluble epoxide hydrolase metabolites, the DHETs, with more severe knee symptoms at 2 years provides a rationale for further investigation into the role of this pathway in persisting knee symptoms in this population, including potential therapeutic strategies.

Toward designing human intervention studies to prevent osteoarthritis after knee injury: A report from an interdisciplinary OARSI 2023 workshop.

Objective: The global impact of osteoarthritis is growing. Currently no disease modifying osteoarthritis drugs/therapies exist, increasing the need for preventative strategies. Knee injuries have a high prevalence, distinct onset, and strong independent association with post-traumatic osteoarthritis (PTOA). Numerous groups are embarking upon research that will culminate in clinical trials to assess the effect of interventions to prevent knee PTOA despite challenges and lack of consensus about trial design in this population. Our objectives were to improve awareness of knee PTOA prevention trial design and discuss state-of-the art methods to address the unique opportunities and challenges of these studies. Design: An international interdisciplinary group developed a workshop, hosted at the 2023 Osteoarthritis Research Society International Congress. Here we summarize the workshop content and outputs, with the goal of moving the field of PTOA prevention trial design forward. Results: Workshop highlights included discussions about target population (considering risk, homogeneity, and possibility of modifying osteoarthritis outcome); target treatment (considering delivery, timing, feasibility and effectiveness); comparators (usual care, placebo), and primary symptomatic outcomes considering surrogates and the importance of knee function and symptoms other than pain to this population. Conclusions: Opportunities to test multimodal PTOA prevention interventions across preclinical models and clinical trials exist. As improving symptomatic outcomes aligns with patient and regulator priorities, co-primary symptomatic (single or aggregate/multidimensional outcome considering function and symptoms beyond pain) and structural/physiological outcomes may be appropriate for these trials. To ensure PTOA prevention trials are relevant and acceptable to all stakeholders, future research should address critical knowledge gaps and challenges.

The influence of sex hormones on musculoskeletal pain and osteoarthritis.

The association of female sex with certain rheumatic symptoms and diseases is now indisputable. Some of the most striking examples of this association occur in individuals with musculoskeletal pain and osteoarthritis, in whom sex-dependent changes in incidence and prevalence of disease are seen throughout the lifecourse. Joint and muscle pain are some of the most common symptoms of menopause, and there is increasingly compelling evidence that changes in or loss of sex hormones (be it natural, autoimmune, pharmacological, or surgical) influence musculoskeletal pain propensity and perhaps disease. However, the effects of modulation or replacement of sex hormones in this context are far less established, particularly whether these approaches could represent a preventative or therapeutic opportunity once symptoms have developed. In this Review, we present evidence for the association of changes in sex hormones with musculoskeletal pain and painful osteoarthritis, discussing data from diverse natural, therapeutic, and experimental settings in humans and relevant animal models relating to hormone loss or replacement and the consequent effects on health, pain, and disease. We also postulate mechanisms by which sex hormones could mediate these effects. Further research is needed; however, increased scientific understanding of this complex area could lead to real benefits in musculoskeletal and women's health.

Hormone replacement therapy (conjugated oestrogens plus bazedoxifene) for post-menopausal women with symptomatic hand osteoarthritis: primary report from the HOPE-e randomised, placebo-controlled, feasibility study.

Background: Symptomatic hand osteoarthritis is more common in women than in men, and its incidence increases around the age of menopause, implicating oestrogen deficiency. No randomised controlled trials of hormone replacement therapy (HRT) have been done in people with hand osteoarthritis. We aimed to determine the feasibility and acceptability of a form of HRT (conjugated oestrogens plus bazedoxifene) in post-menopausal women with painful hand osteoarthritis. Methods: The HOPE-e feasibility study was a randomised, double-blind, placebo-controlled trial, for which we recruited women aged 40-65 years, for whom 1-10 years had passed after their final menstrual period, with definite hand osteoarthritis and at least two painful hand joints. Participants were recruited across three primary or secondary care sites and from the community and were randomly assigned (1:1) to receive conjugated oestrogens plus bazedoxifene or placebo, orally once every day for 24 weeks, before weaning for 4 weeks until the end of the study. The primary feasibility outcomes were rates of identification, recruitment, randomisation, retention, and compliance of eligible participants, and the likelihood of unmasking. The secondary objective was to generate proof-of-concept quantitative and qualitative data on the acceptability of proposed clinical outcomes for a full trial and adverse events. We used an intention-to-treat analysis, and criteria for progression to a full trial were pre-defined as recruitment of at least 30 participants across all sites in 18 months; a dropout rate of less than or equal to 30% of randomised individuals; and acceptability to the majority of participants, including acceptable rates of adverse events. Due to the COVID-19 pandemic, the recruitment window was reduced to 12-15 months. A proportionately reduced minimum sample size of 22 was judged to be sufficient to test feasibility. This trial was registered at ISRCTN, ISRCTN12196200. Findings: From May 9, 2019 to Dec 31, 2020, 434 enquiries or referrals were received. We did 96 telephone pre-screens; of the 35 eligible participants, seven were excluded as ineligible at the telephone or face-to-face screening and 28 (80% [95% CI 63-92]) were randomly assigned. Of the 406 who were not randomly assigned, 250 (62%) were ineligible (with contraindicated medications accounting for 50 [20%] of these), 101 (25%) did not respond to further enquiries, and 55 (14%) chose not to proceed (with the most common reason being not wanting to take a hormone-based drug). All 28 randomised participants completed all follow-up assessments with high compliance and outcome measure completeness. All three adverse event-related treatment withdrawals were in the placebo group. No serious adverse events were reported. Participants and investigators were successfully masked (participant Bang's blinding index placebo group 0·50 [95% CI 0·25-0·75]). The trial met the prespecified criteria for progression to a full trial. Interpretation: This first-ever feasibility study of a randomised controlled trial of HRT for post-menopausal women with painful hand osteoarthritis met its progression criteria, although it was not powered to detect a clinical effect. This outcome indicates that a full trial of an HRT in this population is feasible and acceptable and identifies potential refinements with regard to the design of such a trial. Funding: Research for Patient Benefit programme, National Institute for Health Research.

Variants in ALDH1A2 reveal an anti-inflammatory role for retinoic acid and a new class of disease-modifying drugs in osteoarthritis.

More than 40% of individuals will develop osteoarthritis (OA) during their lifetime, yet there are currently no licensed disease-modifying treatments for this disabling condition. Common polymorphic variants in ALDH1A2, which encodes the key enzyme for synthesis of all-trans retinoic acid (atRA), are associated with severe hand OA. Here, we sought to elucidate the biological significance of this association. We first confirmed that ALDH1A2 risk variants were associated with hand OA in the U.K. Biobank. Articular cartilage was acquired from 33 individuals with hand OA at the time of routine hand OA surgery. After stratification by genotype, RNA sequencing was performed. A reciprocal relationship between ALDH1A2 mRNA and inflammatory genes was observed. Articular cartilage injury up-regulated similar inflammatory genes by a process that we have previously termed mechanoflammation, which we believe is a primary driver of OA. Cartilage injury was also associated with a concomitant drop in atRA-inducible genes, which were used as a surrogate measure of cellular atRA concentration. Both responses to injury were reversed using talarozole, a retinoic acid metabolism blocking agent (RAMBA). Suppression of mechanoflammation by talarozole was mediated by a peroxisome proliferator-activated receptor gamma (PPARγ)-dependent mechanism. Talarozole was able to suppress mechano-inflammatory genes in articular cartilage in vivo 6 hours after mouse knee joint destabilization and reduced cartilage degradation and osteophyte formation after 26 days. These data show that boosting atRA suppresses mechanoflammation in the articular cartilage in vitro and in vivo and identifies RAMBAs as potential disease-modifying drugs for OA.

Research priorities to reduce the impact of musculoskeletal disorders: a priority setting exercise with the child health and nutrition research initiative method.

Involving research users in setting priorities for research is essential to ensure the outcomes are patient-centred and maximise its value and impact. The Musculoskeletal Disorders Research Advisory Group Versus Arthritis led a research priority setting exercise across musculoskeletal disorders. The Child Health and Nutrition Research Initiative (CHNRI) method of setting research priorities with a range of stakeholders was used, involving four stages and two surveys, to: (1) gather research uncertainties, (2) consolidate these, (3) score uncertainties against importance and impact, and (4) analyse scoring for prioritisation. 213 people responded to the first survey and 285 people to the second, representing clinicians, researchers, and people with musculoskeletal disorders. Key priorities included developing and testing new treatments, better treatment targeting, early diagnosis, prevention, and better understanding and management of pain, with an emphasis on understanding underpinning mechanisms. We present a call to action to researchers and funders to target these priorities.

Prevention of posttraumatic osteoarthritis at the time of injury: Where are we now, and where are we going?

This overview of progress made in preventing post-traumatic osteoarthritis (PTOA) was delivered in a workshop at the Orthopaedics Research Society Annual Conference in 2019. As joint trauma is a major risk factor for OA, defining the molecular changes within the joint at the time of injury may enable the targeting of biological processes to prevent later disease. Animal models have been used to test therapeutic targets to prevent PTOA. A review of drug treatments for PTOA in rodents and rabbits between 2016 and 2018 revealed 11 systemic interventions, 5 repeated intra-articular or topical interventions, and 5 short-term intra-articular interventions, which reduced total Osteoarthritis Research Society International scores by 30%-50%, 20%-70%, and 0%-40%, respectively. Standardized study design, reporting of effect size, and quality metrics, alongside a "whole joint" approach to assessing efficacy, would improve the translation of promising new drugs. A roadblock to translating preclinical discoveries has been the lack of guidelines on the design and conduct of human trials to prevent PTOA. An international workshop addressing this in 2016 considered inclusion criteria and study design, and advocated the use of experimental medicine studies to triage candidate treatments and the development of early biological and imaging biomarkers. Human trials for the prevention of PTOA have tested anakinra after anterior cruciate ligament rupture and dexamethasone after radiocarpal injury. PTOA offers a unique opportunity for defining early mechanisms of OA to target therapeutically. Progress in trial design and high-quality preclinical research, and allegiance with patients, regulatory bodies, and the pharmaceutical industry, will advance this field.

Clinical and molecular associations with outcomes at 2 years after acute knee injury: a longitudinal study in the Knee Injury Cohort at the Kennedy (KICK).

BACKGROUND: Joint injury is a major risk factor for osteoarthritis and provides an opportunity to prospectively examine early processes associated with osteoarthritis. We investigated whether predefined baseline demographic and clinical factors, and protein analytes in knee synovial fluid and in plasma or serum, were associated with clinically relevant outcomes at 2 years after knee injury. METHODS: This longitudinal cohort study recruited individuals aged 16-50 years between Nov 1, 2010, and Nov 28, 2014, across six hospitals and clinics in London, UK. Participants were recruited within 8 weeks of having a clinically significant acute knee injury (effusion and structural injury on MRI), which was typically treated surgically. We measured several predefined clinical variables at baseline (eg, time from injury to sampling, extent and type of joint injury, synovial fluid blood staining, presence of effusion, self-reported sex, age, and BMI), and measured 12 synovial fluid and four plasma or serum biomarkers by immunoassay at baseline and 3 months. The primary outcome was Knee Injury and Osteoarthritis Outcome Score (KOOS4) at 2 years, adjusted for baseline score, assessed in all patients. Linear and logistic regression models adjusting for predefined covariates were used to assess associations between baseline variables and 2-year KOOS4. This study is registered with ClinicalTrials.gov, number NCT02667756. FINDINGS: We enrolled 150 patients at a median of 17 days (range 1-59, IQR 9-26) after knee injury. 123 (82%) were male, with a median age of 25 years (range 16-50, IQR 21-30). 98 (65%) of 150 participants completed a KOOS4 at 2 (or 3) years after enrolment (50 participants were lost to follow-up and two were withdrawn due to adverse events unrelated to study participation); 77 (51%) participants had all necessary variables available and were included in the core variable adjusted analysis. In the 2-year dataset mean KOOS4 improved from 38 (SD 18) at baseline to 79 (18) at 2 years. Baseline KOOS4, medium-to-large knee effusion, and moderate-to-severe synovial blood staining and their interaction significantly predicted 2-year KOOS4 (n=77; coefficient -20·5, 95% CI -34·8 to -6·18; p=0·0060). The only predefined biomarkers that showed independent associations with 2-year KOOS4 were synovial fluid MCP-1 (n=77; -0·015, 0·027 to -0·004 per change in 1 pg/mL units; p=0·011) and IL-6 (n=77; -0·0005, -0·0009 to -0·0001 per change in 1 pg/mL units; p=0·017). These biomarkers, combined with the interaction of effusion and blood staining, accounted for 39% of outcome variability. Two adverse events occurred that were linked to study participation, both at the time of blood sampling (one presyncopal episode, one tenderness and pain at the site of venepuncture). INTERPRETATION: The combination of effusion and haemarthrosis was significantly associated with symptomatic outcomes after acute knee injury. The synovial fluid molecular protein response to acute knee injury (best represented by MCP-1 and IL-6) was independently associated with symptomatic outcomes but not with structural outcomes, with the biomarkers overall playing a minor role relative to clinical predictors. The relationship between symptoms and structure after acute knee injury and their apparent dissociation early in this process need to be better understood to make clinical progress. FUNDING: Versus Arthritis, Kennedy Trust for Rheumatology Research, and NIHR Oxford Biomedical Research Centre.

Hand Osteoarthritis: investigating Pain Effects of estrogen-containing therapy (HOPE-e): a protocol for a feasibility randomised placebo-controlled trial.

BACKGROUND: Hand osteoarthritis (OA) is a common condition, causing pain, stiffness and reduced quality of life. Incidence is higher amongst women, particularly around the age of the menopause. Whilst the relationship between sex hormones and OA has been studied in vitro, in epidemiological studies and in clinical trials of hormone replacement therapy (HRT), this study is the first to investigate the effect of estrogen-containing therapy on hand pain in post-menopausal women with symptomatic hand OA in a randomised study design. METHODS: This is a feasibility study of a double-blinded placebo-controlled intervention with 1:1 randomisation to either a combination of conjugated estrogens 0.45 mg and bazedoxifene acetate 20 mg (Duavive) or placebo. The target population is post-menopausal women with symptomatic hand OA, aiming to recruit 60-90 study participants. The primary objective is to assess the feasibility of a future fully powered randomised controlled trial (RCT). Participants will take the study medication for 24 weeks and be followed up for 28 weeks after randomisation. The primary outcomes used to determine feasibility are eligible participant identification rates and routes; recruitment, randomisation and retention rates of eligible participants; study medication compliance; and the likelihood of unintentional unblinding. Secondary outcomes include measures of hand pain, function, appearance and menopausal symptoms. An end of study questionnaire and focus groups will help to refine the final protocol for a full study. DISCUSSION: Identifying new treatments for symptomatic hand OA is a recognised research priority. The study will help us to understand whether there are sufficient interested and eligible individuals in this target population who would consider HRT for their hand symptoms. It will provide proof-of-concept RCT data on the effects of HRT on hand pain and other clinically relevant outcomes in this population. The study will gain valuable information on the feasibility of a full RCT and how best to run this. The findings will be published in a peer-reviewed journal and presented at a relevant conference. TRIAL REGISTRATION: ISRCTN12196200 registered on 15 January 2019.