Pain Trajectories in Knee Osteoarthritis-A Systematic Review and Best Evidence Synthesis on Pain Predictors

Interactions of cumulative load with biomarkers of cartilage turnover predict knee cartilage change over 2 years: data from the osteoarthritis initiative

The purpose was to investigate relationships of cumulative load and cartilage turnover biomarkers with 2-year changes in cartilage in knee osteoarthritis. From participants with Kellgren-Lawrence (KL) grades of 1 to 3, cartilage thickness and transverse relaxation time (T2) were computed from 24-month (baseline) and 48-month magnetic resonance images. Cumulative load was the interaction term of the Physical Activity Scale for the Elderly (PASE) and body mass index (BMI). Serum cartilage oligomeric matrix protein (COMP) and the nitrated form of type II collagen (Coll2-1 NO2) were collected at baseline. Multiple regressions (adjusted for baseline age, KL grade, cartilage measures, pain, comorbidity) evaluated the relationships of cumulative load and biomarkers with 2-year changes. In 406 participants (63.7 (8.7) years), interactions of biomarkers with cumulative load weakly predicted 2-year cartilage changes: (i) COMP × cumulative load explained medial tibia thickness change (R2 increased 0.062 to 0.087, p < 0.001); (ii) Coll2-1 NO2 × cumulative load explained central medial femoral T2 change (R2 increased 0.177 to 0.210, p < 0.001); and (iii) Coll2-1 NO2 × cumulative load explained lateral tibia T2 change (R2 increased 0.166 to 0.188, p < 0.001). Moderate COMP or Coll2-1 NO2 at baseline appeared protective. High COMP or Coll2-1 NO2, particularly with high BMI and low PASE, associated with worsening cartilage. Moderate serum concentrations of cartilage turnover biomarkers, at high and low physical activity, associated with maintained cartilage outcomes over 2 years. In conclusion, high concentrations of cartilage turnover biomarkers, particularly with high BMI and low physical activity, associated with knee cartilage thinning and increasing T2 over 2 years. Key Points • Higher quality cartilage may be better able to tolerate a larger cumulative load than poor quality cartilage. • Among participants enrolled in the Osteoarthritis Initiative Biomarkers Consortium Project, a representation of cumulative load exposure and its interaction with cartilage turnover biomarkers were weakly related with 2-year change in knee cartilage. • These findings suggest that cartilage turnover is a factor that modifies the relationship between loading exposure and cartilage loss in knee OA.

Significance of radiographic temporomandibular degenerative joint disease findings

The field of orthodontics has seen a recent increase in the number of patients over the age of 50 seeking treatment and also an increase in the use of cone beam technology. Similar to other joints in the body, the temporomandibular joint (TMJ) is associated with age-related degeneration. However, unlike other joints, degeneration of the TMJ is rarely symptomatic and when there is pain, it is usually self-limiting. In this article, we will review: a) the incidence and prevalence of TMJ degenerative diseases, b) similarities and differences of TMJ vs knee degenerative diseases, and c) current treatment recommendations for TMJ degenerative diseases. In the vast majority of people, radiographic evidence of TMJ degeneration is an incidental finding. Future longitudinal research is needed to follow the natural course of TMJ degenerative patients.

Movement-evoked pain is not associated with pain at rest or physical function in knee osteoarthritis

INTRODUCTION

Knee Osteoarthritis (KOA) is mainly characterized by pain. The assessment of KOA-related pain frequently focuses on different constructs subject to sources of bias or drawbacks, as the classical Pain at Rest (PAR). Movement-evoked pain (MEP), recently defined as 'pain during walking', emerges as a differential concept, since PAR and MEP are driven by different underlying mechanisms. Given the novelty of the MEP approach, its association with PAR or with different performance-based tests has not been studied in KOA yet.

MATERIALS AND METHODS

A cross sectional study was conducted. PAR was measured, alongside the performance of four mobility tests and their corresponding MEP: Timed Up and Go Test, 10-metre Walk Test, 2-Minute Walk Test, and 6-Minute Walk Test. Association and agreement were explored for MEP versus PAR, while the correlation of the tests versus each corresponding MEP-measure was assessed.

RESULTS

Neither association nor agreement were found in the duality MEP versus PAR. Also, the lack of association between the performance of a mobility test and the perceived level of pain during the development of the test was stated.

CONCLUSION

Movement-evoked pain is neither related to pain at rest nor to functional performance in subjects affected by knee osteoarthritis. The results from our study suggest that MEP and pain at rest measure and refer to different constructs in knee osteoarthritis. The implementation of MEP as an outcome in exercise-therapy could enhance the tracking of results, as well as the development of tailored interventions under different conditions.

SIGNIFICANCE

This research elucidates the relevance of MEP, recently defined as 'pain during walking', through the analysis of its association with PAR and with functional performance (measured through four mobility tests) in knee osteoarthritis. The results from our study highlight the absence of either association or agreement between MEP and PAR, fact that supports and endorses the idea that both concepts measure and refer to different constructs in knee osteoarthritis.

Clinical Assessment of Osteoarthritis Pain: Contemporary Scenario, Challenges, and Future Perspectives

The multifaceted nature of osteoarthritis (OA) pain presents a challenge in understanding and managing the condition. The diverse pain experiences, progression rates, individual responses to treatments, and complex disease mechanisms contribute to heterogeneity in the clinical studies outcomes. The lack of a standardized methodology for assessing and classifying OA pain challenges healthcare practitioners. This complicates the establishment of universally applicable protocols or standardized guidelines for treatment. This article explores the heterogeneity observed in clinical studies evaluating OA pain treatments, highlighting the necessity for refined methodologies, personalized patient categorization, and consistent outcome measures. It discusses the role of the multidimensional nature of OA pain, underlying pain mechanisms, and other contributing factors to the heterogeneity in outcome measures. Addressing these variations is crucial to establishing a more consistent framework for evidence-based treatments and advancing care of the patient with OA pain.

Longitudinal Characterization of Pain Interference and Influential Factors in Former National Football League (NFL) Players Over a 19-Year Period: An NFL-LONG Study

Previous studies on pain experiences in retired contract sport athletes have been cross-sectional, leaving gaps in our understanding of the evolution of pain interference (PI) and factors that influence trajectories decades after sport discontinuation. This study investigated the longitudinal course of PI in former male National Football League (NFL) players over a 19-year period following sport discontinuation and examined factors influencing overall levels and trajectories of PI. Former NFL players completed health surveys in 2001, 2010, and 2019, with PI ratings measured using the 36-Item Short Form Health Survey (2001 and 2010) and the Patient-Reported Outcomes Measurement Information System (2019). Unconditional latent growth curve models analyzed overall PI severity and trajectories. Conditional latent growth curve models explored the influence of musculoskeletal injuries, osteoarthritis (OA), and depression diagnosis on PI. Over 19 years (N = 338; mean age = 48.96 ± 9.35), PI significantly increased (slope = .179, P < .001; mean Patient-Reported Outcomes Measurement Information System PI t-scores 2001 = 54.19, 2010 = 54.64, 2019 = 57.38). Cumulative musculoskeletal injuries (B = .092, P < .001) and baseline depression diagnosis (B = 4.463, P < .001) were associated with overall PI levels but not change over time. OA was significantly associated with overall PI levels (B = 6.536, P < .001) and trajectory (B = -.253, P < .001); those endorsing OA in 2001 had lower PI increases over 19 years. The body region of injury and level of play during injuries mirrored overall injury effects. PI mildly increased over 19 years, with multiple factors independently influencing overall PI levels. Enhancing former contact sport athletes' daily functionality may be achieved through holistic biopsychosocial interventions addressing musculoskeletal injuries, OA, and depression. Future research should identify factors influencing elevated trajectories of long-term PI post-sport discontinuation. PERSPECTIVE: This study assessed PI in former NFL athletes over 2 decades, revealing notable interindividual variability in trajectories over time. Musculoskeletal injuries, depression, and OA correlated with overall PI. Prevention and intervention in these 3 areas present the potential to improve disruptions in daily living due to pain in former athletes.

What do people living with chronic pain want from a pain forecast? A research prioritization study

Because people with chronic pain feel uncertain about their future pain, a pain-forecasting model could support individuals to manage their daily pain and improve their quality of life. We conducted two patient and public involvement activities to design the content of a pain-forecasting model by learning participants' priorities in the features provided by a pain forecast and understanding the perceived benefits that such forecasts would provide. The first was a focus group of 12 people living with chronic pain to inform the second activity, a survey of 148 people living with chronic pain. Respondents prioritized forecasting of pain flares (100, or 68%) and fluctuations in pain severity (94, or 64%), particularly the timing of the onset and the severity. Of those surveyed, 75% (or 111) would use a future pain forecast and 80% (or 118) perceived making plans (e.g., shopping, social) as a benefit. For people with chronic pain, the timing of the onset of pain flares, the severity of pain flares and fluctuations in pain severity were prioritized as being key features of a pain forecast, and making plans was prioritized as being a key benefit.

Is the Rate of Responders to Hyaluronic Acid Injection for Patients with Knee Osteoarthritis Stable Over Time? Post hoc Analyses of a 6-Month Follow-Up Study

INTRODUCTION

Recently, a study showing the non-inferiority of a single injection of sodium hyaluronate plus sorbitol (Synolis VA®) compared to hylan G-F20 (Synvisc-One®) over a 24-week period in patients with knee osteoarthritis was published. The objective of the present study is to assess if a short-term response to a single injection of sodium hyaluronate plus sorbitol can be maintained over a 6 month-period and if the maintenance of the response to treatment is dependent on the functional status at baseline.

METHODS

Responders to treatment at days 28, 84, and 168 were evaluated according to the responder criteria proposed by the OMERACT-OARSI. The Western Ontario and McMaster Universities Arthritis Index (WOMAC) was used to assess functional status at baseline. All analyses were adjusted for age, gender, BMI, and baseline WOMAC total score using data from the intention-to-treat (ITT) population.

RESULTS

Out of the 96 patients included in the study who were receiving Synolis VA®, 59.38% were responders at day 28 according to the OMERACT/OARSI responder criteria, 59.78% at day 84, and 64.52% at day 168. Among the responders at D28, the probability of being responder at D84 and D168 was significantly higher than among non-responders, with corresponding odds ratio (95% CI) of 2.85 (1.07-7.59) and 7.28 (2.53-20.93), respectively. Patients with a poorer physical function at baseline were more likely to respond to the treatment at all time points, compared to those with a better physical function (OR 3.74 [1.37-10.21]).

CONCLUSIONS

An early response of a single injection of sodium hyaluronate plus sorbitol is predictive of long-term response, up to 24 weeks. Patients with a poorer physical function may best benefit from the treatment.

Determination and characterization of patient subgroups based on pain trajectories in hand osteoarthritis

OBJECTIVES

To investigate pain, pain trajectories and their determinants in hand osteoarthritis (OA).

METHODS

Data from the HOSTAS (Hand OSTeoArthritis in Secondary care) consisting of consecutive hand OA patients were used. Australian Canadian Osteoarthritis Hand Index (AUSCAN) pain was measured yearly for four years. Patients with complete AUSCAN at ≥2 time points were eligible for longitudinal analysis. Associations between variables of interest and baseline AUSCAN pain were investigated with linear regression. Development of pain over time was modelled using latent class growth analysis (LCGA). Associations of LCGA classes with variables of interest were analysed using multinomial logistic regression adjusted for baseline pain.

RESULTS

A total of 484/538 patients [mean (s.d.) age 60.8 (8.5) years, 86% women, mean (s.d.) AUSCAN pain 9.3 (4.3)] were eligible for longitudinal analysis. Sex, marital and working status, education, disease duration and severity, anxiety and depression scores, lower health-related quality of life (HR-QoL), specific illness perceptions and coping styles were associated with baseline pain. LCGA yielded three classes, characterized by average pain levels at baseline; average pain remained stable over time within classes. Classes with more pain were positively associated with BMI, tender joint count, symptom duration, hand function scores and depression scores, negatively with physical HR-QoL, and education level.

CONCLUSION

Baseline pain was associated with patient and disease characteristics, and psychosocial factors. LCGA showed three pain trajectories in hand OA patients, with different baseline pain levels and stable pain over time. Classes were distinguished by BMI, education level, disease severity, depression and HR-QoL.

Factors Associated with Osteoarthritis and Their Influence on Health-Related Quality of Life in Older Adults with Osteoarthritis: A Study Based on the 2020 Korea National Health and Nutrition Examination Survey

Numerous studies have investigated factors associated with osteoarthritis (OA), but few have investigated their effects on psychological problems and health-related quality of life in older adults with OA. We aimed to investigate factors associated with OA and their influence on health-related quality of life in older adults with OA. Among 1394 participants aged ≥65 years, 952 and 442 were categorized into the OA and non-OA groups, respectively. Comprehensive data on demographic characteristics, medical conditions, health-related quality of life, blood test results, and nutritional intake were obtained. Univariate and multivariate logistic regression analyses were used to evaluate the odds ratio for factors associated with OA, including age (odds ratio (OR), 1.038; p = 0.020), female sex (OR, 5.692; p < 0.001), body mass index (OR, 1.108; p < 0.001), hypertension (OR, 1.451; p < 0.050), hyperlipidemia (OR, 1.725; p = 0.001), osteoporosis (OR, 2.451; p < 0.001), and depression (OR, 2.358; p = 0.041). The OA group showed a significantly lower subjective health status (p < 0.001) and higher difficulty in mobility (p < 0.001) and pain/discomfort (p = 0.010) than the non-OA group. The sleeping hours were significantly shorter in the OA group than those in the non-OA group (p = 0.013). OA was a significant contributing factor for unfavorable health-related quality of life in older adults. Controlling the factors associated with OA should be prioritized, and health-related quality of life should be monitored in older adults with OA.

Quantifying sustained pain worsening in knee osteoarthritis

OBJECTIVE

Recent work suggests that many persons with knee osteoarthritis (OA) experience stable symptoms over time. Whether patients experience periods of symptom exacerbation or flare which interrupt this stable course, and how long such periods last, has received little study. Our objective is to describe the frequency and duration of episodes of pain worsening in persons with knee OA.

METHODS

We selected participants from the Osteoarthritis Initiative with radiographic, symptomatic knee OA. We defined a clinically relevant increase in knee pain as an increase in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain of ≥9 points. We defined sustained worsening as maintaining at least 80% of the initial increase. We used Poisson regression to estimate the incidence rate (IR) of episodes of pain worsening.

RESULTS

1093 participants were included in the analysis. Eighty-eight percent had ≥1 increase in WOMAC pain ≥9 points (IR: 26.3 per 100 person years (95% CI: 25.2, 27.4)). Forty-eight percent had ≥1 episode of sustained worsening (IR: 9.7 per 100 person-years (95% CI: 8.9, 10.5)). Elevated pain was maintained an average of 2.4 years after the initial increase.

CONCLUSION

Most participants with knee OA reported at least one clinically relevant increase in WOMAC pain, but fewer than half experienced an episode of sustained pain worsening. These individual-level data portray a more nuanced and fluctuating course of OA pain than suggested by trajectory studies. These data could be useful in shared decision-making regarding prognosis and treatment choices in persons affected by symptomatic knee OA.

Infrared Thermography in Symptomatic Knee Osteoarthritis: Joint Temperature Differs Based on Patient and Pain Characteristics

The aim of this study was to evaluate osteoarthritis (OA) patients with infrared thermography to investigate imaging patterns as well as demographic and clinical characteristics that influence knee inflammation. Forty patients with one-sided symptomatic knee OA were included and evaluated through knee-specific PROMs and the PainDETECT Questionnaire for neuropathic pain evaluation. Thermograms were captured using a thermographic camera FLIR-T1020 and temperatures were extracted using the software ResearchIR for the overall knee and the five ROIs: medial, lateral, medial patella, lateral patella, and suprapatellar. The mean temperature of the total knee was 31.9 ± 1.6 °C. It negatively correlated with age (rho = −0.380, p = 0.016) and positively correlated with BMI (rho = 0.421, p = 0.007) and the IKDC objective score (tau = 0.294, p = 0.016). Men had higher temperatures in the knee medial, lateral, and suprapatellar areas (p = 0.017, p = 0.019, p = 0.025, respectively). Patients with neuropathic pain had a lower temperature of the medial knee area (31.5 ± 1.0 vs. 32.3 ± 1.1, p = 0.042), with the total knee negatively correlating with PainDETECT (p = 0.045). This study demonstrated that the skin temperature of OA symptomatic knees is influenced by demographic and clinical characteristics of patients, with higher joint temperatures in younger male patients with higher BMI and worst objective knee scores and lower temperatures in patients affected by neuropathic pain.

Pain Trajectory after Short-Stay Anorectal Surgery: A Prospective Observational Study

The evolution of pain after anorectal surgery has not been well characterized. The main objective of this study is to evaluate patterns in acute postoperative pain in patients undergoing short-stay anorectal surgery. A total of 217 patients were included in the study, which used group-based trajectory modeling to estimate postoperative pain and then examined the relationships between sociodemographic or surgical factors and pain trajectories. Three distinct postoperative pain trajectories were determined: hemorrhoidectomy (OR, 0.15), higher anxiety (OR, 3.26), and a higher preoperative pain behavior score (OR, 3.15). In multivariate analysis, they were associated with an increased likelihood of being on the high pain trajectory. The pain trajectory group was related to postoperative analgesic use (p < 0.001), with the high-low group needing more nonsteroidal analgesics. The study showed that there were three obvious pain trajectories after anorectal surgery, including an unreported low-moderate-low type. More than 60% of patients maintained moderate to severe pain within 7 days after the operation. These postoperative pain trajectories were predominantly defined by surgery factors and patient factors.

The Minimal Clinically Important Difference Changes Greatly Based on the Different Calculation Methods

BACKGROUND

The minimal clinically important difference (MCID) for patient-reported outcome measures (PROMs) expresses both the extent of the improvement and the value that patients place on it. MCID use is becoming increasingly widespread to understand the clinical efficacy of a given treatment, define guidelines for clinical practice, and properly interpret trial results. However, there is still large heterogeneity in the different calculation methods.

PURPOSE

To calculate and compare the MCID threshold values of a PROM by applying various methods and analyzing their effect on the study results interpretation.

STUDY DESIGN

Cohort study (Diagnosis); Level of evidence, 3.

METHODS

The data set used to investigate the different MCID calculation approaches was based on a database of 312 patients affected by knee osteoarthritis and treated with intra-articular platelet-rich plasma. MCID values were calculated on the International Knee Documentation Committee (IKDC) subjective score at 6 months using 2 approaches: 9 methodologies referred to an anchor-based approach and 8 methodologies to a distribution-based approach. The obtained threshold values were applied to the same series of patients to understand the effect of using different MCID methods in evaluating patient response to treatment.

RESULTS

The different methods employed led to MCID values ranging from 1.8 to 25.9 points. The anchor-based methods ranged from 6.3 to 25.9, while the distribution-based ones were from 1.8 to 13.8 points, showing a 4.1× variation of the MCID values within the anchor-based methods and a 7.6× variation within the distribution-based methods. The percentage of patients who reached the MCID for the IKDC subjective score changed based on the specific calculation method used. Among the anchor-based methods, this value varied from 24.0% to 66.0%, while among the distribution-based methods, the percentage of patients reaching the MCID varied from 44.6% to 75.9%.

CONCLUSION

This study proved that different MCID calculation methods lead to highly heterogeneous values, which significantly affect the percentage of patients achieving the MCID in a given population. The wide-ranging thresholds obtained with the different methodologies make it difficult to evaluate the real effectiveness of a given treatment questioning the usefulness of MCID, as currently available, in the clinical research.

Test-retest precision and longitudinal cartilage thickness loss in the IMI-APPROACH cohort

OBJECTIVE

To investigate the test-retest precision and to report the longitudinal change in cartilage thickness, the percentage of knees with progression and the predictive value of the machine-learning-estimated structural progression score (s-score) for cartilage thickness loss in the IMI-APPROACH cohort - an exploratory, 5-center, 2-year prospective follow-up cohort.

DESIGN

Quantitative cartilage morphology at baseline and at least one follow-up visit was available for 270 of the 297 IMI-APPROACH participants (78% females, age: 66.4 ± 7.1 years, body mass index (BMI): 28.1 ± 5.3 kg/m², 55% with radiographic knee osteoarthritis (OA)) from 1.5T or 3T MRI. Test-retest precision (root mean square coefficient of variation) was assessed from 34 participants. To define progressor knees, smallest detectable change (SDC) thresholds were computed from 11 participants with longitudinal test-retest scans. Binary logistic regression was used to evaluate the odds of progression in femorotibial cartilage thickness (threshold: -211 μm) for the quartile with the highest vs the quartile with the lowest s-scores.

RESULTS

The test-retest precision was 69 μm for the entire femorotibial joint. Over 24 months, mean cartilage thickness loss in the entire femorotibial joint reached -174 μm (95% CI: [-207, -141] μm, 32.7% with progression). The s-score was not associated with 24-month progression rates by MRI (OR: 1.30, 95% CI: [0.52, 3.28]).

CONCLUSION

IMI-APPROACH successfully enrolled participants with substantial cartilage thickness loss, although the machine-learning-estimated s-score was not observed to be predictive of cartilage thickness loss. IMI-APPROACH data will be used in subsequent analyses to evaluate the impact of clinical, imaging, biomechanical and biochemical biomarkers on cartilage thickness loss and to refine the machine-learning-based s-score.

CLINICALTRIALS

GOV IDENTIFICATION

NCT03883568.

Recall Bias Affects Pain Assessment in Knee Osteoarthritis: A Pilot Study

OBJECTIVE

The objective of this study was to evaluate the recall bias of symptoms evaluation in knee osteoarthritis (OA).

DESIGN

In this multicentric pilot study, 50 patients with knee OA used a mobile App (Ecological Momentary Assessment [EMA]) to collect pain and function on two 0 to 10 numerical rating scales (NRS) 2 times a day for 2 months. At the 1-month and at the 2-month follow-up visits, patients retrospectively evaluated the mean level of pain/function of the last month. Recall bias was computed as the difference between the mean level of pain/function reported using the App and the level reported with the retrospective assessment. The correlation between the recall bias and patients' characteristics, as well as pain/function trajectories, was analyzed.

RESULTS

A statistically significant recall bias was documented with higher pain reported at 1-month with the retrospective assessment (P < 0.001). These results were confirmed also at the 2-month follow-up (P = 0.002). For function, no significant recall bias was documented. During the first and second months, 47 and 31 patients showed pain peaks, respectively. The number of pain peaks during the first month was correlated with the magnitude of the recall bias (P = 0.02).

CONCLUSIONS

The recall bias influences the retrospective self-assessment of pain at the follow-up visits and the presence of pain peaks, a common event in the patients with OA, increases the magnitude of recall bias. The EMA performed with a mobile App is a useful tool to limit the influence of recall bias in the clinical and research setting evaluation of knee OA.

Predicting Depression in Patients With Knee Osteoarthritis Using Machine Learning: Model Development and Validation Study

Background

Knee osteoarthritis (OA) is the most common form of OA and a leading cause of disability worldwide. Chronic pain and functional loss secondary to knee OA put patients at risk of developing depression, which can also impair their treatment response. However, no tools exist to assist clinicians in identifying patients at risk. Machine learning (ML) predictive models may offer a solution. We investigated whether ML models could predict the development of depression in patients with knee OA and examined which features are the most predictive.

Objective

The primary aim of this study was to develop and test an ML model to predict depression in patients with knee OA at 2 years and to validate the models using an external data set. The secondary aim was to identify the most important predictive features used by the ML algorithms.

Methods

Osteoarthritis Initiative Study (OAI) data were used for model development and external validation was performed using Multicenter Osteoarthritis Study (MOST) data. Forty-two features were selected, which denoted routinely collected demographic and clinical data such as patient demographics, past medical history, knee OA history, baseline examination findings, and patient-reported outcome measures. Six different ML classification models were trained (logistic regression, least absolute shrinkage and selection operator [LASSO], ridge regression, decision tree, random forest, and gradient boosting machine). The primary outcome was to predict depression at 2 years following study enrollment. The presence of depression was defined using the Center for Epidemiological Studies Depression Scale. Model performance was evaluated using the area under the receiver operating characteristic curve (AUC) and F1 score. The most important features were extracted from the best-performing model on external validation.

Results

A total of 5947 patients were included in this study, with 2969 in the training set, 742 in the test set, and 2236 in the external validation set. For the test set, the AUC ranged from 0.673 (95% CI 0.604-0.742) to 0.869 (95% CI 0.824-0.913), with an F1 score of 0.435 to 0.490. On external validation, the AUC varied from 0.720 (95% CI 0.685-0.755) to 0.876 (95% CI 0.853-0.899), with an F1 score of 0.456 to 0.563. LASSO modeling offered the highest predictive performance. Blood pressure, baseline depression score, knee pain and stiffness, and quality of life were the most predictive features.

Conclusions

To our knowledge, this is the first study to apply ML classification models to predict depression in patients with knee OA. Our study showed that ML models can deliver a clinically acceptable level of performance (AUC>0.7) in predicting the development of depression using routinely available demographic and clinical data. Further work is required to address the class imbalance in the training data and to evaluate the clinical utility of the models in facilitating early intervention and improved outcomes.

Does Bone Marrow Edema Influence the Clinical Results of Intra-Articular Platelet-Rich Plasma Injections for Knee Osteoarthritis?

Platelet-rich plasma (PRP) is increasingly used for the intra-articular treatment of knee osteoarthritis (OA). However, clinical studies on PRP injections reported controversial results. Bone marrow edema (BME) can cause symptoms by affecting the subchondral bone and it is not targeted by intra-articular treatments. The aim of this study was to investigate if the presence of BME can influence the outcome of intra-articular PRP injections in knee OA patients. A total of 201 patients were included in the study, 80 with and 121 without BME at the baseline MRI. BME area and site were evaluated, and BME was graded using the Whole-Organ Magnetic Resonance Imaging Score (WORMS). Patients were assessed with International Knee Documentation Committee (IKDC) score Knee injury and Osteoarthritis Outcome Score (KOOS) subscales, the EuroQol-Visual Analogue Scale (EQ-VAS), and the Tegner score at baseline, 2, 6, and 12 months. Overall, the presence of BME did not influence the clinical results of intra-articular PRP injections in these patients treated for knee OA. Patients with BME presented a similar failure rate and clinical improvement after PRP treatment compared to patients without BME. The area and site of BME did not affect clinical outcomes. However, patients with a higher BME grade had a higher failure rate.

A Comprehensive Update of Prolotherapy in the Management of Osteoarthritis of the Knee

This is a comprehensive review of the literature focusing on the use of prolotherapy in the treatment of osteoarthritis of the knee. It covers the background, efficacy, and advantages of prolotherapy in the management of osteoarthritis symptoms and then covers the existing evidence of the use of prolotherapy for this purpose. Current treatments for osteoarthritis of the knee are numerous, yet patients continue to endorse chronic pain and poor quality of life. Prolotherapy is a treatment that has been inadequately studied with poor sample sizes and lack of standardization between trials. However, in recent years the literature on prolotherapy in the treatment of knee osteoarthritis has grown. Although there is still a lack of homogeneity, trials have shown that dextrose prolotherapy, autologous conditioned serum, hyaluronic injections, and normal saline administered either intra- or peri-articularly are comparable in reducing pain scores to other primary treatment options. The mechanism of action for prolotherapy is still unclear, but researchers have found that prolotherapy plays some role in cartilage growth or chondrogenesis and has been shown to have improved radiographic outcomes. Prolotherapy appears to be a safe treatment alternative that has been shown to improve stiffness, pain, function, and quality of life in osteoarthritis of the knee. Knee osteoarthritis is remarkably prevalent in the United States and is one of the most common causes of disability in the elderly population. Although there are many treatment options, patients continue to live with chronic pain which can incur high costs for patients. A safe, long-term, and effective solution has not yet been identified. Prolotherapy has been shown to be a safe option for improving pain, function, and quality of life as effectively as other treatment options.

Risk assessment for hip and knee osteoarthritis using polygenic risk scores

Objective

Polygenic risk scores (PRS) allow risk stratification using common single‐nucleotide polymorphisms (SNPs), and clinical applications are currently explored for several diseases. This study was undertaken to assess the risk of hip and knee osteoarthritis (OA) using PRS.

Methods

We analyzed 12,732 individuals from a population‐based cohort from the Rotterdam Study (n = 11,496), a clinical cohort (Cohort Hip and Cohort Knee [CHECK] study; n = 908), and a high‐risk cohort of overweight women (Prevention of Knee OA in Overweight Females [PROOF] study; n = 328), for the association of the PRS with prevalence/incidence of radiographic OA, of clinical OA, and of total hip replacement (THR) or total knee replacement (TKR). The hip PRS and knee PRS contained 44 and 24 independent SNPs, respectively, and were derived from a recent genome‐wide association study meta‐analysis. Standardized PRS (with Z transformation) were used in all analyses.

Results

We found a stronger association of the PRS for clinically defined OA compared to radiographic OA phenotypes, and we observed the highest PRS risk stratification for TKR/THR. The odds ratio (OR) per SD was 1.3 for incident THR (95% confidence interval [95% CI] 1.1–1.5) and 1.6 (95% CI 1.3–1.9) for incident TKR in the Rotterdam Study. The knee PRS was associated with incident clinical knee OA in the CHECK study (OR 1.3 [95% CI 1.1–1.5]), but not for the PROOF study (OR 1.2 [95% CI 0.8–1.7]). The OR for OA increased gradually across the PRS distribution, up to 2.1 (95% CI 1.4–3.2) for individuals with the 10% highest PRS compared to the middle 50% of the PRS distribution.

Conclusion

Our findings validated the association of PRS across OA definitions. Since OA is becoming frequent and primary prevention is not commonly applicable, PRS‐based risk assessment could play a role in OA prevention. However, the utility of PRS is dependent on the setting. Further studies are needed to test the integration of genetic risk assessment in diverse health care settings.

Short-term pain trajectories in patients with knee osteoarthritis

AIM

It is unknown if pain in knee osteoarthritis (KOA) follows distinct patterns over the short term. Therefore, the aim of this study was to identify whether persons with a previous history of KOA pain fluctuations have distinct trajectories of pain over 90 days and to examine associations between baseline characteristics and pain trajectories.

METHOD

People with a previous history of KOA were selected from a web-based longitudinal study. Baseline variables were sex, age, being obese/overweight, years of KOA, knee injury, knee buckling, satisfactory Lubben Social Support Score, pain and stress scales, Intermittent Constant Osteoarthritis Pain Score (ICOAP), medication use, and physical activity. Participants completed a Knee Injury and Osteoarthritis Outcomes Score (KOOS) pain subscale (KOOS-p, rated 0 = extreme to 100 = no knee problems) at 10-day intervals for 90 days. Short-term KOOS-p trajectories were identified using latent growth mixture modeling and the baseline risk factors for these pain trajectories were examined.

RESULTS

Participants (n = 313) had a mean age of 62.2 (SD ± 8.1) years and and a body mass index of 29.8 (SD ± 6.6) kg/m² . The three-class latent growth mixture modeling quadratic model with best fit indices was chosen (based on lowest sample-size-adjusted Bayesian Information Criterion, high probability of belonging, interpretability). Three distinct pain trajectory clusters (over 90 days) were identified: low-moderate pain at baseline with large improvement (n = 11), minimal change in pain over 90 days (n = 248), and moderate-high pain with worsening (n = 46). Higher ICOAP (intermittent scale), perceived stress, negative affect score, and knee buckling at baseline were associated with a worse knee pain trajectory (P < 0.05).

CONCLUSIONS

Persons with KOA showed unique short-term pain trajectories over 90 days, with distinct characteristics at baseline associated with each trajectory.

Depression in Osteoarthritis: Current Understanding

Depression, one of the most common comorbidities with osteoarthritis (OA), affects patient prognosis and quality of life. It also increases the overall burden of disease. This subgroup of patients has not been effectively managed in clinical settings. The study aimed to direct physicians' attention to the co-occurrence of depression and OA. Therefore, this review summarizes the relevant literature published over the past 10 years. The focus is on the prevalence of and risk factors for depression in OA, the effects of depression on OA development and treatment response, comorbidity mechanisms, screening, and non-pharmacological treatment. The research on the etiology of depression has been driven largely by epidemiological studies. Recent studies have shown that high levels of pain, poor levels of function, high numbers of OA sites, and slow gait might be associated with depression. However, the pathophysiology of OA and depression comorbidities remains unclear. In addition to immune inflammation and structural changes in the brain, which have been documented in brain imaging studies, psychosocial factors may also play a role. The evidence indicates that depression can be treated with early intervention; however, adjustments may need to be made for individuals with comorbid depression in OA. It is recommended that health care providers pay more attention to depressive symptoms in patients with OA. Clinicians should develop and implement an individualized and comprehensive treatment plan for patients based on a mental health assessment and in teams with other professionals to optimize treatment outcomes.

Minimal Clinically Important Difference and Patient Acceptable Symptom State in Patients With Knee Osteoarthritis Treated With PRP Injection

Background:

Although several injection-based treatments have been proposed to address knee osteoarthritis (OA), it is often difficult to understand the clinical relevance of the obtained results. The psychometric measures of minimal clinically important difference (MCID) and Patient Acceptable Symptom State (PASS) were developed to better interpret study findings.

Purpose:

To establish the MCID and the PASS for the International Knee Documentation Committee (IKDC) Subjective score and the Knee injury and Osteoarthritis Outcome Score (KOOS) in patients treated with intra-articular platelet-rich plasma (PRP) injections for knee OA.

Study Design:

Case series; Level of evidence, 4.

Methods:

This study included 215 patients with knee OA (68% men, 32% women; age, 53.2 ± 11.3 years; body mass index, 26.8 ± 4.3 kg/m²) who underwent intra-articular PRP injections. Patients were assessed through the IKDC Subjective score and KOOS subscales, and the MCID and the PASS for both measures were independently calculated at 6 and 12 months post-injection. The MCID was calculated using the value equal to half of the standard deviation of the overall cohort improvement. The PASS was assessed using a 2-point scale (satisfied or not satisfied), with threshold values being detected through a receiver operating characteristic curve analysis and the Youden index to maximize the sensitivity and the specificity of the threshold values.

Results:

All scores improved significantly from baseline to 6 months and baseline to 12 months (P < .001 for all scores). All scores were stable from 6 to 12 months except for the KOOS Quality of Life subscale, which improved further (P = .033). For the IKDC, the MCID values were 8.6 and 8.5 points and the PASS scores were 59.7 and 62.1 at 6 and 12 months, respectively. Overall, the MCID and the PASS for all KOOS subscales remained constant at the 2 follow-up points. The percentage of patients who achieved the MCID and the PASS was higher than 85% at both 6 and 12 months post-injection.

Conclusion:

This study provided the MCID and PASS thresholds for the IKDC and KOOS scores in patients with knee OA treated with PRP injections. These psychometric measures may allow a better interpretation of the clinical relevance of injection-based treatment outcomes for knee OA.

Intra-Articular Administration of Autologous Purified Adipose Tissue Associated with Arthroscopy Ameliorates Knee Osteoarthritis Symptoms

The aim of this study was to evaluate the safety and efficacy of the intra-articular administration of autologous purified adipose tissue to treat knee osteoarthritis (OA) following arthroscopy. Thirty patients with radiological evidence of knee OA were recruited. A small liposuction and arthroscopic lavage and debridement were performed in the same surgical time. The harvested fat was processed intraoperatively with Lipocell (Tiss’You, RSM) to purify the adipose tissue injected into the knee. Clinical evaluations were performed with VAS, Womac, and Lequesne questionnaires before treatment and after 1, 3, 6, and 12 months of follow-up. Pain, measured with VAS, significantly decreased, showing a reduction of 53% after 1 month and 83% after a year. Functional recovery, measured with Womac, showed an improvement of 47% after 1 month post-treatment and 84% after 1 year. No adverse effects have been observed. The intra-articular administration of purified adipose tissue associated with arthroscopic lavage and debridement is a safe and significantly effective strategy in improving the symptoms of knee osteoarthritis in up to 1 year of follow-up.

Knee pain trajectories over 18 months in non-Hispanic Black and non-Hispanic White adults with or at risk for knee osteoarthritis

BACKGROUND

Pain is the hallmark symptom of knee osteoarthritis (OA), and varies widely across individuals. Previous research has demonstrated both fluctuating and stable pain trajectories in knee OA using various time periods. Changes in pain assessed quarterly (i.e. 3-month intervals) in knee OA are relatively unknown. The current study aimed to investigate temporal variations in pain over a one and a half year period (18 months) based on quarterly characteristic pain assessments, and to examine differences in pain patterns by sociodemographic and baseline pain characteristics.

METHODS

The sample included a prospective cohort of 188 participants (mean age 58 years; 63% female; 52% non-Hispanic Black) with or at risk for knee OA from an ongoing multisite investigation of ethnic/race group differences. Knee pain intensity was self-reported at baseline and quarterly over an18-month period. Baseline pain assessment also included frequency, duration, and total number of pain sites. Group-based trajectory modeling was used to identify distinct pain trajectories. Multinomial logistic regression was used to examine associations between sociodemographic characteristics, risk factors, and pain trajectory groups.

RESULTS

Pain trajectories were relatively stable among a sample of adults with knee pain. Four distinct pain trajectories emerged in the overall sample, with the largest proportion of participants (35.1%) classified in the moderate-high pain group. There were significant relationships between age, education, income, ethnicity/race and trajectory group; with younger, less educated, lower income, and non-Hispanic Black participants had a greater representation in the highest pain trajectory group.

CONCLUSIONS

Pain remained stable across a one and a half-year period in adults with or at risk for knee osteoarthritis, based on quarterly assessments. Certain sociodemographic variables (e.g. ethnicity/race, education, income, age) may contribute to an increased risk of experiencing greater pain.