Risk factors for joint replacement in knee osteoarthritis; a 15-year follow-up study

Association of MRI-based knee osteoarthritis structural phenotypes with short-term structural progression and subsequent total knee replacement

BACKGROUND

The failure of disease-modifying osteoarthritis drugs (DMOADs) trials lies mainly in the heterogeneity of the disease, which calls for a more precise population with specific progression and outcomes. This study aimed to determine whether and which MRI-based structural phenotype of knee osteoarthritis (KOA) is associated with short-term structural progression and subsequent total knee replacement (TKR).

METHODS

A longitudinal study was conducted among participants with baseline Kellgren-Lawrence grade (KLG) ≥ 2 from the Osteoarthritis Initiative (OAI). The structural phenotypes at baseline were defined as subchondral bone, meniscus/cartilage and inflammatory phenotypes according to the MRI Osteoarthritis Knee Score (MOAKS). The primary outcome was the progression of structural abnormalities within 24 months and multivariable logistic regressions were applied to evaluate the associations. The secondary outcome was the incidence of TKR during 108 months. Cox regressions and Kaplan-Meier survival curves were used for the analysis.

RESULTS

A total of 733 participants with KOA were finally included in our study, with 493 (67.3%) having the three main structural phenotypes. For the primary outcome, the subchondral bone phenotype (OR [95% CI]:1.71 [1.02, 2.83], 1.52 [1.06, 2.18], 1.65 [1.11, 2.42], respectively) and the inflammatory phenotype (OR [95% CI]: 1.69 [1.05, 2.74], 1.82 [1.31, 2.52], 2.15 [1.48, 3.14], respectively) were both associated with the short-term progression of joint space narrowing, osteophytes and sclerosis in 24 months, whereas the meniscus/cartilage phenotype was only associated with the progression of osteophytes and sclerosis. For the secondary outcome, the subchondral bone phenotype (HR [95% CI]: 1.71 [1.06-2.78]) and inflammatory phenotype (HR [95%CI]: 2.00 [1.02-2.67]) were associated with shorter time to subsequent TKR, but not the meniscus/cartilage phenotype. Besides, the cumulative effect when the structural phenotype overlapped was confirmed in both outcomes.

CONCLUSIONS

The subchondral bone phenotype and inflammatory phenotype were associated with the progression of joint space narrowing, osteophytes and sclerosis in 24 months, along with subsequent TKR in 108 months. Besides, additive effects of overlapped phenotypes were further determined. These phenotypes could serve as valuable screening tools for future clinical trials and provide guidance for risk evaluation.

Extensive Metallosis in a Primary Knee Arthroplasty as a Result of Polyethylene Wear: Is It Avoidable?

Metallosis is known to occur in metal-on-metal arthroplasty and has been of concern to orthopaedic surgeons worldwide. It is a rare, late complication of total knee arthroplasty (TKA), in which metal-on-metal contact leads to metal debris deposition in the surrounding tissue. Reasons for metal-on-metal contact could range from wear of the polyethylene insert to abnormal joint biomechanics. Many components can affect the development of metallosis, with polyethylene wear being the most common cause of metallosis. This paper discusses the case of an 85-year-old man who developed metallosis, attributed to polyethylene wear, 24 years after undergoing TKA. It also highlights the different components of knee prostheses, evaluates the efficacy of different types of polyethylene, and explores whether ceramic coating can improve TKA outcomes and reduce complications such as metallosis.

Genkwanin suppresses mitochondrial dysfunction to alleviate IL-1β-elicited inflammation, apoptosis, and degradation of extracellular matrix in chondrocytes through upregulating DUSP1

Osteoarthritis (OA) is a form of chronic degenerative disease contributing to elevated disability rate among the elderly. Genkwanin is an active component extracted from Daphne genkwa possessing pharmacologic effects. Here, this study is designed to expound the specific role of genkwanin in OA and elaborate the probable downstream mechanism. First, the viability of chondrocytes in the presence or absence of interleukin-1 beta (IL-1β) treatment was detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay was used to assess cell apoptosis. Inflammatory response was estimated through enzyme-linked immunosorbent assay and Western blot. In addition, immunofluorescence staining and Western blot were utilized to measure the expression of extracellular matrix (ECM)-associated proteins. Dual-specificity protein phosphatase-1 (DUSP1) expression was tested by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blot. Following DUSP1 elevation in genkwanin-treated chondrocytes exposed to IL-1β, inflammatory response and ECM-associated factors were evaluated as forementioned. In addition, 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazolocarbocyanine iodide staining was to assess the mitochondrial membrane potential. Adenosine triphosphate (ATP) level was examined with ATP assay kit, and RT-qPCR was used to test mitochondrial DNA expression. Results indicated that genkwanin administration enhanced the viability while ameliorated the apoptosis, inflammatory response, and ECM degradation in IL-1β-induced chondrocytes. Besides, genkwanin treatment fortified DUSP1 expression in IL-1β-exposed chondrocytes. DUSP1 interference further offsets the impacts of genkwanin on the inflammation, ECM degradation, and mitochondrial dysfunction in IL-1β-challenged chondrocytes. In short, genkwanin enhanced DUSP1 expression to mitigate mitochondrial dysfunction, thus ameliorating IL-1β-elicited inflammation, apoptosis, and degradation of ECM in chondrocytes.

Dual-energy CT virtual non-calcium: an accurate method for detection of knee osteoarthritis-related edema-like marrow signal intensity

OBJECTIVES

To evaluate the performance of a dual-energy computed tomography (DECT) virtual non-calcium (VNCa) technique in the detection of edema-like marrow signal intensity (ELMSI) in patients with knee joint osteoarthritis (OA) compared to magnetic resonance imaging (MRI).

METHODS

The study received local ethics board approval, and written informed consent was obtained. DECT and MRI were used to examine 28 knees in 24 patients with OA. VNCa images were generated by dual-energy subtraction of calcium. The knee joint was divided into 15 regions for ELMSI grading, performed independently by two musculoskeletal radiologists, with MRI as the reference standard. We also analyzed CT numbers through receiver operating characteristics and calculated cut-off values.

RESULTS

For the qualitative analysis, we obtained CT sensitivity (Readers 1, 2 = 83.7%, 89.8%), specificity (Readers 1, 2 = 99.5%, 99.5%), positive predictive value (Readers 1, 2 = 95.3%, 95.7%), and negative predictive value (Readers 1, 2 = 97.9%, 98.7%) for ELMSI. The interobserver agreement was excellent (κ = 0.92). The area under the curve for Reader 1 and Reader 2 was 0.961 (95% CI 0.93, 0.99) and 0.992 (95% CI 0.98, 1.00), respectively. CT numbers obtained from the VNCa images were significantly different between regions with and without ELMSI (p < .001).

CONCLUSIONS

VNCa images have good diagnostic performance for the qualitative and quantitative analysis of knee osteoarthritis-related ELMSI.

Prediction of total knee replacement using deep learning analysis of knee MRI

Current methods for assessing knee osteoarthritis (OA) do not provide comprehensive information to make robust and accurate outcome predictions. Deep learning (DL) risk assessment models were developed to predict the progression of knee OA to total knee replacement (TKR) over a 108-month follow-up period using baseline knee MRI. Participants of our retrospective study consisted of 353 case-control pairs of subjects from the Osteoarthritis Initiative with and without TKR over a 108-month follow-up period matched according to age, sex, ethnicity, and body mass index. A traditional risk assessment model was created to predict TKR using baseline clinical risk factors. DL models were created to predict TKR using baseline knee radiographs and MRI. All DL models had significantly higher (p < 0.001) AUCs than the traditional model. The MRI and radiograph ensemble model and MRI ensemble model (where TKR risk predicted by several contrast-specific DL models were averaged to get the ensemble TKR risk prediction) had the highest AUCs of 0.90 (80% sensitivity and 85% specificity) and 0.89 (79% sensitivity and 86% specificity), respectively, which were significantly higher (p < 0.05) than the AUCs of the radiograph and multiple MRI models (where the DL models were trained to predict TKR risk using single contrast or 2 contrasts together as input). DL models using baseline MRI had a higher diagnostic performance for predicting TKR than a traditional model using baseline clinical risk factors and a DL model using baseline knee radiographs.

Tensile strain and altered synovial tissue metabolism in human knee osteoarthritis

Synovium is critical for maintaining joint homeostasis and may contribute to mechanobiological responses during joint movement. We investigated mechanobiological responses of whole synovium from patients with late-stage knee osteoarthritis (OA). Synovium samples were collected during total knee arthroplasty and assigned to histopathology or cyclic 10% tensile strain loading, including (1) static (control); (2) low-frequency (0.3 Hz); and iii) high-frequency (1.0 Hz) for 30-min. After 6-h incubation, tissues were bisected for RNA isolation and immunostaining (3-nitrotyrosine; 3-NT). RNA sequencing was analyzed for differentially expressed genes and pathway enrichment. Cytokines and lactate were measured in conditioned media. Compared to controls, low-frequency strain induced enrichment of pathways related to interferon response, Fc-receptor signaling, and cell metabolism. High-frequency strain induced enrichment of pathways related to NOD-like receptor signaling, high metabolic demand, and redox signaling/stress. Metabolic and redox cell stress was confirmed by increased release of lactate into conditioned media and increased 3-NT formation in the synovial lining. Late-stage OA synovial tissue responses to tensile strain include frequency-dependent increases in inflammatory signaling, metabolism, and redox biology. Based on these findings, we speculate that some synovial mechanobiological responses to strain may be beneficial, but OA likely disturbs synovial homeostasis leading to aberrant responses to mechanical stimuli, which requires further validation.

Alterations in peripheral joint muscle force control in adults with musculoskeletal disease, injury, surgery, or arthroplasty: A systematic review and meta-analysis

PURPOSE

To systematically review and analyse whether musculoskeletal conditions affect peripheral joint muscle force control (i.e. magnitude and/or complexity of force fluctuations).

METHODS

A literature search was conducted using MEDLINE, CINAHL and SPORTDiscus databases (from inception-8th April 2021) for studies involving: 1) participants with musculoskeletal disease, injury, surgery, or arthroplasty in the peripheral joints of the upper/lower limb; 2) comparison with an unaffected control group or unaffected contralateral limb; and 3) measures of the magnitude and/or complexity of force fluctuations during targeted isometric contractions. The methodological quality of studies was evaluated using a modified Downs and Black Quality Index. Studies were combined using the standardized mean difference (SMD) in a random-effects model.

RESULTS

14 studies (investigating 694 participants) were included in the meta-analysis. There was a significant effect of musculoskeletal conditions on peripheral joint muscle force coefficient of variation (CV; SMD = 0.19 [95 % CI 0.06, 0.32]), whereby individuals with musculoskeletal conditions exhibited greater CV than controls. Subgroup analyses revealed that CV was only greater: 1) when comparison was made between symptomatic and asymptomatic individuals (rather than between affected and contralateral limbs; SMD = 0.22 [95 % CI 0.07, 0.38]); 2) for conditions of the knee (SMD = 0.29 [95 % CI 0.14, 0.44]); and 3) for ACL injury post-surgery (SMD = 0.56 [95 % CI 0.36, 0.75]).

CONCLUSION

Musculoskeletal conditions result in an increase in peripheral joint muscle force CV, with this effect dependent on study design, peripheral joint, and surgical status. The greater force CV is indicative of decreased force steadiness and could have implications for long-term tissue health/day-to-day function.

Knockdown of NEK7 alleviates anterior cruciate ligament transection osteoarthritis (ACLT)-induced knee osteoarthritis in mice via inhibiting NLRP3 activation

Osteoarthritis is thought to be a NLRP3-related disease. NEK7 is an essential mediator for NLRP3 inflammasome activation. This study aimed to demonstrate whether NEK7 has regulatory roles in the pathogenesis of osteoarthritis. C57BL/6 mice were subjected to anterior cruciate ligament transection osteoarthritis (ACLT) for constructing animal models of osteoarthritis. Injection of adeno-associated virus (AAV) expressing NEK7-specific shRNA into the knee joints of mice, following of which immunohistochemistry, qRT-PCR, western blotting, Safranin-O Fast Green staining, ELISA, and co-immunoprecipitation were performed to determine the effects of NEK7. NEK7 was highly expressed in the joint tissues of ACLT mice. As compared with shScr, AAV delivery of NEK7 shRNA significantly inhibited cartilage degeneration, OARSI score, and serum CTX-II and COMP levels. AAV delivery of NEK7 shRNA downregulated the expression of matrix-degrading enzymes (ADAMTS-4, MMP3, and MMP13) and upregulated the expression of ECM-related molecules (SOX9, collagen II, and aggrecan). In addition, AAV delivery of NEK7 shRNA alleviated ACLT-induced synovial inflammation, as was evidenced by the decreased levels of TNF-α, IL-6, IL-1β, and IL-18 and increased levels of IL-10. In the joint tissues of ACLT mice, NEK7 interacted with NLRP3 proteins. AAV delivery of NEK7 shRNA inhibited the protein interaction, and thereby inhibited the activation of the NLRP3 inflammasome. AAV delivery of NEK7 shRNA has no significant effects on cartilage degeneration and synovial inflammation in Nlrp3^-/- mice. In conclusion, knockdown of NEK7 exerted anti-osteoarthritic effects, possibly via inhibiting the activation of the NLRP3 inflammasome. This study provided a novel mechanism of NEK7-NLRP3 interaction affecting osteoarthritis.

Test-Retest Reliability and Sensitivity to Change of Ultrasound-Based Methods of Measuring Synovial Inflammation in Knee Osteoarthritis

OBJECTIVES

To assess test-retest reliability of musculoskeletal ultrasound (US) measures of inflammation in patients with knee osteoarthritis (OA) and to assess the sensitivity to change of US measures of inflammation in patients with knee OA.

METHODS

To mimic a common clinical scenario, 36 patients (n = 70 knees) with symptomatic knee OA who were in stable condition underwent 2 assessments within 14 days by different operators and different US machines, graded by a single rater. Test-retest reliability was measured using Cohen's kappa coefficient, intraclass correlation coefficient (ICC), and absolute agreement parameters. A total of 51 patients (n = 72 knees) were tested immediately before and 21-28 days after intraarticular glucocorticoid injection to investigate sensitivity to change and longitudinal construct validity. Paired t-tests and standardized response mean (SRM) were used to assess sensitivity to change. Multivariate linear regression was used to investigate longitudinal construct validity of US with Knee Injury and Osteoarthritis Outcome Score (KOOS) pain scores, while adjusting for covariates.

RESULTS

US measures of inflammation demonstrated moderate (κ = 0.41, 0.60) to substantial (κ = 0.61, 0.80) agreement. Quantitative measures of synovitis and effusion demonstrated good test-retest reliability (ICC_2,1 0.71, 0.92). US measures of synovitis and effusion demonstrated low-to-moderate sensitivity to change (SRM -0.29, -0.50). The associations between changes in US measures and KOOS pain scores over time were low, and 95% confidence intervals included zero.

CONCLUSION

In a clinical setting, US measures of inflammatory features of knee OA have substantial reliability and low-to-moderate sensitivity to change, whereas measures of structural OA features are less reliable. Longitudinal construct validity of US measures of synovitis and effusion to KOOS pain scores is not strongly supported.

Mid-term prognosis of the stromal vascular fraction for knee osteoarthritis: a minimum 5-year follow-up study

Background

The short-term safety and efficacy of stromal vascular fraction (SVF) in treating knee osteoarthritis (KOA) have been extensively studied but the mid-term and long-term prognoses remain unknown.

Methods

126 KOA patients were recruited and randomly assigned to SVF group and hyaluronic acid (HA) group (control group). The scores of visual analogue scale (VAS) and the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) were assessed and compared between the two groups 1, 2, 3, and 5 years after treatment. The endpoint was defined as surgeries related to KOA or clinical scores exceeding the patient acceptable symptom state (PASS).

Results

The VAS and WOMAC scores in the SVF group were significantly better than those in the HA group during the 5-year follow-up after treatment. The average responsive time to SVF treatment (61.52 months) was significantly longer than HA treatment (30.37 months). The adjusted Cox proportional hazards model showed that bone marrow lesion (BML) severity, body mass index (BMI) and treatment were independent risk factors and that the use of SVF reduced the risk of clinical failure by 2.602 times. The cartilage volume was reduced in both the SVF and control groups at 5 years but reduced less in the SVF group.

Conclusions

Up to 5 years after SVF treatment, acceptable clinical state was present for approximately 60% of patients. BML severity and BMI were independent predictors of the prognosis.

Trial Registry: This study was retrospectively registered at Chinses Clinical Trial Registry with identifier ChiCTR2100052818 and was approved by ethics committee of the First Affiliated Hospital of Zhejiang Chinese Medical University, number 2013-X-063.

Prediction models for the risk of total knee replacement: development and validation using data from multicentre cohort studies

Background

Few prognostic prediction models for total knee replacement are available, and the role of radiographic findings in predicting its use remains unclear. We aimed to develop and validate predictive models for total knee replacement and to assess whether adding radiographic findings improves predictive performance.

Methods

We identified participants with recent knee pain (in the past 3 months) in the Multicenter Osteoarthritis Study (MOST) and the Osteoarthritis Initiative (OAI). The baseline visits of MOST were initiated in 2003 and of OAI were initiated in 2004. We developed two predictive models for the risk of total knee replacement within 60 months of follow-up by fitting Cox proportional hazard models among participants in MOST. The first model included sociodemographic and anthropometric factors, medical history, and clinical measures (referred to as the clinical model). The second model added radiographic findings into the predictive model (the radiographic model). We evaluated each model's discrimination and calibration performance and assessed the incremental value of radiographic findings using both category-free net reclassification improvement (NRI) and integrated discrimination improvement (IDI). We tuned the models and externally validated them among participants in OAI.

Findings

We included 2658 participants from MOST (mean age 62·4 years [SD 8·1], 1646 [61·9%] women) in the training dataset and 4060 participants from OAI (mean age 60·9 years [9·1], 2379 [58·6%] women) in the validation dataset. 290 (10·9%) participants in the training dataset and 174 (4·3%) in the validation dataset had total knee replacement. The retained predictive variables included in the clinical model were age, sex, race, history of knee arthroscopy, frequent knee pain, current use of analgesics, current use of glucosamine, body-mass index, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain score, and the most predictive factors were age, race, and WOMAC pain score. The retained predictive variables in the radiographic model were age, sex, race, frequent knee pain, current use of analgesics, WOMAC pain score, and Kellgren-Lawrence grade, and the most predictive factors were Kellgren-Lawrence grade, race, and age. The C-statistic was 0·79 (95% CI 0·76-0·81) for the clinical model and 0·87 (0·85-0·99) for the radiographic model in the training dataset. The calibration slope was 0·95 (95% CI 0·86-1·05) and 0·96 (0·87-1·04), respectively. Adding radiograph findings significantly improved predictive performance with an NRI of 0·43 (95% CI 0·38-0·50) and IDI of 0·14 (95% CI: 0·10-0·18). Both models, with tuned coefficients, showed a good predictive performance among participants in the validation dataset.

Interpretation

The risk of total knee replacement can be predicted based on common risk factors with good discrimination and calibration. Additionally, adding radiographic findings of knee osteoarthritis into the model substantially improves its predictive performance.

Funding

National Natural Science Foundation of China, National Key Research and Development Program, and Beijing Municipal Science & Technology Commission.

Changes to the activity and sensitivity of nerves innervating subchondral bone contribute to pain in late-stage osteoarthritis

ABSTRACT

Although it is clear that osteoarthritis (OA) pain involves activation and/or sensitization of nociceptors that innervate knee joint articular tissues, much less is known about the role of the innervation of surrounding bone. In this study, we used monoiodoacetate (MIA)-induced OA in male rats to test the idea that pain in OA is driven by differential contributions from nerves that innervate knee joint articular tissues vs the surrounding bone. The time-course of pain behavior was assayed using the advanced dynamic weight-bearing device, and histopathology was examined using haematoxylin and eosin histology. Extracellular electrophysiological recordings of knee joint and bone afferent neurons were made early (day 3) and late (day 28) in the pathogenesis of MIA-induced OA. We observed significant changes in the function of knee joint afferent neurons, but not bone afferent neurons, at day 3 when there was histological evidence of inflammation in the joint capsule, but no damage to the articular cartilage or subchondral bone. Changes in the function of bone afferent neurons were only observed at day 28, when there was histological evidence of damage to the articular cartilage and subchondral bone. Our findings suggest that pain early in MIA-induced OA involves activation and sensitization of nerves that innervate the joint capsule but not the underlying subchondral bone, and that pain in late MIA-induced OA involves the additional recruitment of nerves that innervate the subchondral bone. Thus, nerves that innervate bone should be considered important targets for development of mechanism-based therapies to treat pain in late OA.

Knee Intraosseous Injections: A Systematic Review of Clinical Evidence of Different Treatment Alternatives

OBJECTIVE

To systematically review the available clinical evidence regarding the safety and efficacy of knee intraosseous injections for the treatment of bone marrow lesions in patients affected by knee osteoarthritis.

DESIGN

A literature search was carried out on PubMed, Embase, and Google Scholar databases in January 2020. The following inclusion criteria were adopted: (1) studies of any level of evidence, dealing with subchondral injection of bone substitute materials and/or biologic agents; (2) studies with minimum 5 patients treated; and (3) studies with at least 6 months' follow-up evaluation. All relevant data concerning clinical outcomes, adverse events, and rate of conversion to arthroplasty were extracted.

RESULTS

A total of 12 studies were identified: 7 dealt with calcium phosphate administration, 3 with platelet-rich plasma, and 2 with bone marrow concentrate injection. Only 2 studies were randomized controlled trials, whereas 6 studies were prospective and the remaining 4 were retrospective. Studies included a total of 459 patients treated with intraosseous injections. Overall, only a few patients experienced adverse events and clinical improvement was documented in the majority of trial. The lack of any comparative evaluation versus subchondral drilling alone is the main limitation of the available evidence.

CONCLUSIONS

Knee intraosseous injections are a minimally invasive and safe procedure to address subchondral bone damage in osteoarthritic patients. They are able to provide beneficial effects at short-term evaluation. More high-quality evidence is needed to confirm their potential and to identify the best product to adopt in clinical practice.

Exploring the Mechanism of Resveratrol in Reducing the Soft Tissue Damage of Osteoarthritis Based on Network Pharmacology and Experimental Pharmacology

AIM

To explore the mechanism of resveratrol in reducing the soft tissue damage of osteoarthritis (OA) based on network pharmacology.

METHODS

Pharmmapper was used to predict the target of resveratrol, OMIM and Genecards were used to collect OA-related disease genes, and David ver 6.8 was used for enrichment analysis. Then, animal experiments were carried out for verification. The rat OA model was established and the rats were randomly divided into 4 groups: model group, resveratrol low-dose group, resveratrol high-dose group, and blank control group for follow-up experiments. Hematoxylin-eosin (HE) staining was used to detect the degree of pathological damage of rat bones and joints. Enzyme-linked immunosorbent assay (ELISA) was used for the content of inflammatory factors. Western blot was used to detect the expression of Toll-like receptor 4 (TLR4), Myeloid differentiation factor 88 (MyD88), nuclear factor kappa B protein (NF-κB), cysteine protease-9 (CASP-9), Bcl-2 protein, and Bax protein.

RESULTS

Through network pharmacological analysis, this study found that resveratrol may regulate the TLR4 signaling pathway, PI3K-Akt signaling pathway, FoxO signaling pathway, Osteoclast differentiation, Rheumatoid arthritis, etc. Animal experiments showed that compared with the model group, the pathological damage of bone and joint in the resveratrol low-dose and high-dose groups was significantly improved. Compared with the model group, the serum levels of IL-1beta, IL-6, IL-17, TNF-α, and MCP-1 in the resveratrol low-dose and high-dose groups were significantly reduced (P < 0.05); protein levels of TLR-4, MyD88, and NF-κB p65 were significantly reduced (P < 0.05); caspase-9 and Bax protein levels were significantly reduced (P < 0.05), and Bcl-2 was significantly increased (P < 0.05).

CONCLUSION

Resveratrol may inhibit the activation of the TLR4-mediated NF-κB signaling pathway and has a repairing effect on soft tissue damage in OA.

The predictive significance of bone mineral density on postoperative pain relief in knee osteoarthritis patients after total knee arthroplasty: A prediction model

BACKGROUND

Bone mineral density (BMD) may be an important factor affecting the clinical outcomes after total knee arthroplasty (TKA). However, further information regarding BMD in postoperative pain relief is not present yet. This study aims to gain further insight into the predictive significance of BMD in postoperative pain relief in knee osteoarthritis (KOA) patients after TKA.

METHODS

156 KOA patients treated by TKA were included in this study. Visual analogue scale (VAS) was used to measure the pain intensity in patients within one year after TKA. The patients were divided into good pain relief group (the improvement of VAS ≥ 3) and poor pain relief group (the improvement of VAS < 3). BMD and other clinical characteristics were also collected. Logistic regression analysis and receiver operating characteristic curve (ROC curve) were used to evaluate the predictive significance of BMD. Subgroup analysis was used to compare the difference of postoperative pain between High BMD group and Low BMD group extra.

RESULTS

34 (21.8%) patients had poor pain relief after TKA. Logistic regression analysis indicated that age, BMD, preoperative hospital for special surgery (HSS) scores, preoperative VAS score and postoperative posterior slope angles (PSA) were the risk factors of poor pain relief (P < 0.05). Using BMD as a predictor, the optimum cut-off value of poor pain relief was T-level = -3.0 SD in the ROC curve, where sensitivity and specificity were 73.5% and 83.7%, respectively. Based on this cut-off value, obvious pain relief was observed in the High BMD group compared with Low BMD group from the 6th month after TKA in the subgroup analysis (P < 0.05).

CONCLUSIONS

BMD is an effective predictor for postoperative pain relief in KOA patients after TKA, and the poor pain relief should be fully considered especially when BMD T-level ≤ -3.0 SD.

Validation of a new topographic classification of bone marrow lesions in the knee: the six-letter system

PURPOSE

The aim of this study was to propose and validate a new six-item topographical classification of knee bone marrow lesions in coronal MRI images, to provide an easy-to-use aid to describe their location in a more reproducible and accurate way.

METHODS

This study was conducted in four phases. The first was to do a literature search for methods of describing bone marrow lesions in MRI of the knee. The second was creation of a six-area topographic classification of bone marrow lesions in coronal MRI of the knee. The third phase was selection of cases with bone marrow lesions on knee MRI performed in a single hospital between January of 2017 and December of 2018. The fourth phase was categorization of the bone marrow lesions' location according to the new proposed classification by three independent examiners, two orthopedic surgeons and one radiologist. Patient's demographic data and associated lesions were collected. The inter-observer and intra-observer reliability of the proposed classification was then calculated.

RESULTS

MRI examination of 4000 patients were studied and in 520 patients a total of 666 bone marrow lesions were identified and their location classified using the new system. The inter-observer and intra-observer reliability analysis found a Fleiss' Kappa value of 0.96 (0.95-0.97) and 0.97 (0.96-0.97), respectively, confirming the high reproducibility of the proposed classification.

CONCLUSIONS

The proposed six-location classification of bone marrow lesions is highly reproducible and can help researchers develop studies and share information in a more accurate and reliable way. The correct classification of bone marrow lesions can lead to a more accurate description of this pathology and help clinicians to propose appropriate therapies for this group of patients.

LEVEL OF EVIDENCE

V.

Meniscus tears accelerate joint space loss and lateral meniscal extrusion increases risk of knee arthroplasty in middle-aged adults

We sought to use publicly available data from the Osteoarthritis Initiative (OAI), a multicenter prospective cohort study, to determine the rate of joint space loss and likelihood of knee arthroplasty due to magnetic resonance imaging (MRI)-diagnosed meniscal tears or meniscal extrusion in middle-aged adults with no to mild knee osteoarthritis. Participants (n = 2199; mean age, 60.2 years) with Kellgren-Lawrence osteoarthritis grades 2 (mild) (48.7%) or 0 to 1 (none) (51.3%) underwent knee MRIs at enrollment and were followed radiographically for 8 years and for total knee arthroplasty (TKA) for 9 years. Rate of joint space loss and risk of arthroplasty due to meniscal tears and/or extrusion were determined by multivariate modeling. Prevalence of baseline medial meniscus tears was 21.3% and lateral tears was 12.8%; 26.9% had medial meniscal extrusion (79.6%, <2 mm; 20.4%, +2 mm) and 5.4% had lateral extrusion (75.9%, <2 mm; 24.1%, +2 mm). Median medial joint space loss was 0.06 mm/y and lateral was 0.05 mm/y. Medial tears regardless of extrusion were associated with accelerated medial joint space loss (additional mean, 0.05 mm/y; P = .001). Lateral tears were associated with accelerated lateral joint space loss (additional 0.09 mm/y; P < .001) as was lateral extrusion (additional 0.10 mm/y; P < .001). The yearly incidence of knee arthroplasty was 0.5% without lateral extrusion, 1.5% with extrusion less than 2.0 mm, and 3.7% with extrusion greater than or equal to 2.0 mm. Both medial and lateral tears accelerate joint space loss in middle-aged adults. Lateral meniscal extrusion further accelerates joint space loss and increases risk of progression to TKA within 9 years.

Randomized controlled trial of aquatic exercise for treatment of knee osteoarthritis in elderly people

Aim

The aim of this study is to assess the efficacy of aquatic exercise on pain, gait, and balance among elderly patients with knee osteoarthritis.

Methods

We performed a randomized controlled trial at a university hospital. Overall, 32 men with knee osteoarthritis, aged ≥ 60 years, were included. Pain, balance, and gait were evaluated before and 2 months after interventions. The group control used acetaminophen and followed lifestyle recommendations. The intervention group performed the aquatic exercise three sessions per week for 8 weeks.

Results

At the end of the study, mean pain scores were significantly different between the groups (p = 0.010). Within-group analyses showed that group intervention experienced significant pain relief (p = 0.019), whereas group control did not show the significant change (p = 0.493). There was significant improvement in favor of aquatic exercise with regard to static (p = 0.001) and dynamic (p = 0.001) balance, step length (p = 0.038), stride length (p < 0.001), and cadence (p < 0.001). However, we did not find a significant difference in step time and width between the two groups.

Conclusions

Aquatic exercise would be beneficial in decreasing subjective pain of osteoarthritis. There are some recognizable improvements in patients’ gait and balance as well.

Target-based approach for osteoarthritis treatment

There is still no definitive treatment for knee osteoarthritis (OA). We are certainly far from a consensus on the best form of treatment or on an effective treatment recommendation. There are reasons for the current equivocal treatment recommendations in the face of this very serious health problem. The greatest of these reasons, undoubtedly, is the great complexity of the factors involved in the development and progression of knee OA and the complex pathophysiology including mechanical, inflammatory, metabolic, post-traumatic, molecular, genetic, and psychological changes. For several years, an attempt has been made to correlate different patient phenotypes to different patterns of response to treatment, thus creating the possibility of developing specific treatments for certain groups of patients and theoretically allowing better treatment efficacy. However, in practice we still find totally different responses and evolutions even in individuals belonging to the same phenotype. Thus, classification by phenotypes, despite being an advance, is not sufficient. The present article proposes a fragmented look at each of the many factors or targets involved in the genesis and evolution of OA. Therefore, we propose not the treatment of OA per se but the management of an individual set of targets to achieve personalized OA management. We believe that, paradoxically, by fragmenting the view of the disease we will be able to treat our patients more holistically in an individualized way.

The efficacy and safety of Botulinum Toxin Type A in painful knee osteoarthritis: a systematic review and meta-analysis

Objective

A systematic review and meta-analysis was carried out to evaluate the efficacy and safety of Botulinum Toxin Type A in painful knee osteoarthritis.

Methods

The EMBASE and MEDLINE databases were searched to identify randomized controlled trials (RCTs) of Botulinum Toxin Type A in the treatment of painful knee osteoarthritis. The references of included literature were also searched.

Results

Five articles involving 5 RCTs including 314 patients were included in this analysis. There was a significant difference between Botulinum Toxin Type A and placebo in the visual analog scale (VAS) pain scale and Western Ontario & McMaster Universities Osteoarthritis Index (WOMAC) questionnaire score in both the short-term (≤4 weeks) and long-term (≥8 weeks) treatment period. There were no serious adverse events in the Botulinum Toxin Type A groups.

Conclusions

This meta-analysis suggests that Botulinum Toxin Type A is effective and safe in the painful knee OA treatment. However, high-quality randomized controlled studies are still needed to further confirm our findings.

The Significance of Osteoarthritis-associated Bone Marrow Lesions in the Knee

Bone marrow lesions of the knee in patients with osteoarthritis (OA-BML) are an important clinical entity that may explain progressive pain, decreased quality of life, and impaired function. MRI of OA-BMLs demonstrates a region of subchondral bone with hyperintense marrow signal on T2-weighted images. Histopathology retrieval studies have demonstrated that these lesions correlate with microdamage of the trabecular bone, and subsequently, this leads to a vicious cycle of subchondral bone attrition, attempts at repair, pain, and progressive deformity. These lesions have also been linked to accelerated loss of adjacent articular cartilage and increases in the severity of knee pain, prompting patients to seek musculoskeletal care and treatment. Multiple studies have also correlated the presence of an OA-BML with an increased probability of seeking knee arthroplasty. Knowledge of these lesions is important in the context that knee OA is both a cartilage-based and bone-based disease. Further study of OA-BMLs may provide opportunities for early intervention and OA disease-modifying treatments.

Intra-articular botulinum toxin type A for treatment of knee osteoarthritis: Clinical trial

In recent years, there is a growing interest in new medical applications of botulinum toxin, including pain control, osteoarthritis treatment, and wound healing. While clinical applications of botulinum toxin seem promising, existing evidence regarding the therapeutic effects is still inadequate. The aim was to assess the efficacy of a single injection of abobotulinumtoxin A into the knee joint cavity to reduce pain in elderly people. We carried out a single group clinical trial in a University Hospital. Thirty participants (24 women) more than 50 years of age with knee osteoarthritis were included. Diagnosis of osteoarthritis was based on clinical and radiologic findings. We gave a single injection containing 250 units of Dysport (= 100 units of botulinum neurotoxin type A) diluted with 5 ml of normal saline. The primary outcome measure was knee pain. The secondary outcome was the patients' opinion about their knee and associated problems measured with the Knee injury and Osteoarthritis Outcome Score. The outcomes were measured at the baseline and at 4 weeks after the intervention. Within-group comparisons based on the Knee injury and Osteoarthritis Outcome Scores showed favorable results for joint pain and stiffness, sports, severity of symptoms, quality of life, and daily activities (all p-values < 0.001). Also, pain intensity, joint effusion, knee clicking and locking, and flexion-extension scores showed significant beneficial results (all p-values ≤ 0.005). We concluded that botulinum neurotoxin type A is an effective and safe initial treatment of knee osteoarthritis with clear clinical advantages. Patients' satisfaction, minimum adverse effects in addition to single-dose prescription make the toxin as a choice for the first-line therapy of osteoarthritis at least at the short-term in elderly people. The symptom relief increases the patient's compliance and willing to participate in other therapeutic programs. REGISTRATION: Iranian Registry of Clinical Trials (IRCT) website http://www.irct.ir/, a WHO Primary Register setup, with registration code: Irct ID: IRCT20180416039323N1.

Osteoarthritis year in review 2018: imaging

PURPOSE

To provide a narrative review of the most relevant original research published in 2017/2018 on osteoarthritis imaging.

METHODS

The PubMed database was used to recover all relevant articles pertaining to osteoarthritis and medical imaging published between 1 April 2017 and 31 March 2018. Review articles, case studies and in vitro or animal studies were excluded. The original publications were subjectively sorted based on relevance, novelty and impact.

RESULTS AND CONCLUSIONS

The publication search yielded 1,155 references. In the assessed publications, the most common imaging modalities were radiography (N = 708) and magnetic resonance imaging (MRI) (355), followed by computed tomography (CT) (220), ultrasound (85) and nuclear medicine (17). An overview of the most important publications to the osteoarthritis (OA) research community is presented in this narrative review. Imaging studies play an increasingly important role in OA research, and have helped us to understand better the pathophysiology of OA. Radiography and MRI continue to be the most applied imaging modalities, while quantitative MRI methods and texture analysis are becoming more popular. The value of ultrasound in OA research has been demonstrated. Several multi-modality predictive models have been developed. Deep learning has potential for more automatic and standardized analyses in future OA imaging research.

Abnormal expression of miR-4784 in chondrocytes of osteoarthritis and associations with chondrocyte hyperplasia

The aim of the present study was to assess the expression of microRNA (miRNA)-4784 in the chondrocytes of early osteoarthritis (OA) and to determine the effect of double-stranded (ds)-miRNA-4784 transfection on chondrocyte function. Following the construction of an OA rabbit model, normal chondrocytes (normal control group), OA chondrocytes obtained 4 weeks after modeling (OA at week 4 group) and 8 weeks after modeling (OA at week 8 group) were used. The relative expression of miRNA-4784 in each group was detected using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Western blotting was performed to measure the expression of type II collagen (Col2a1) and matrix metalloproteinase (MMP)-3 in each group with or without ds-miRNA-4784 transfection. The results revealed that the levels of miR-4784 in groups OA at week 4 and 8 were significantly lower than that of normal control group (P<0.05). It was also demonstrated that Col2a1 mRNA expression levels in groups OA at week 4 and 8 were 49 and 38% of that in the normal control group, respectively. Furthermore, MMP-3 mRNA expression levels increased by 3.12- and 3.95-fold in groups OA at week 4 and 8, respectively, compared with those in the normal control group (P<0.01). Following transfection with ds-miRNA-4784, Col2a1 mRNA expression levels increased by 63 and 126% compared with the levels prior to treatment in groups OA at week 4 and 8, respectively (P<0.01). The expression levels of MMP-3 mRNA in groups OA at week 4 and 8 decreased following transfection compared with the levels prior to treatment. Col2a1 and MMP-3 protein expression exhibited similar patterns to the mRNA expression. In summary, the results of the present study suggest that miRNA-4784 expression is significantly reduced in early stage OA chondrocytes. Transfection with ds-miRNA-4784 promotes the expression of Col2a1 and inhibits the MMP-3 expression in chondrocytes.