High prevalence of patellofemoral osteoarthritis in China: a multi-center population-based osteoarthritis study

Morphological analysis of three-dimensional MR images of patellofemoral joints in asymptomatic subjects

The existing methods for analyzing patellofemoral (PF) osteoarthritis (OA) are limited. Our purpose was to clarify the frequency, localization, and morphological progression of PFOA by observing three-dimensional (3D) magnetic resonance (MR) images from a cohort population. The subjects were 561 patients aged 30-79 years from the Kanagawa Knee Study who had not visited a hospital for more than three consecutive months for knee symptoms. MR images of the PF joints, separated into the medial and lateral types, were presented in order of the highest to lowest patella cartilage area ratios. Cartilage defects in the patella were detected in 37 subjects (6.6%). Medial lesions (4.6%) were significantly more frequent than lateral lesions (2.0%) (p < 0.01). For both medial and lateral lesions, the patellar cartilage defects were divided into confined and unconfined types. The 3D MR images of the PF joint showed that the patellar cartilage defect occurred along each ridge of the femoral trochlea. The 3D MR images revealed a 6.6% prevalence of patellar cartilage defects, higher in the medial than lateral regions. The 3D MR images can easily determine PF morphology and cartilage defect location, making them useful in understanding the pathophysiology and etiology of PFOA.

Automatic diagnosis and grading of patellofemoral osteoarthritis from the axial radiographic view: a deep learning-based approach

BACKGROUND

Patellofemoral osteoarthritis (PFOA) has a high prevalence and is assessed on axial radiography of the patellofemoral joint (PFJ). A deep learning (DL)-based approach could help radiologists automatically diagnose and grade PFOA via interpreting axial radiographs.

PURPOSE

To develop and assess the performance of a DL-based approach for diagnosing and grading PFOA on axial radiographs.

MATERIAL AND METHODS

A total of 1280 (dataset 1) axial radiographs were retrospectively collected and utilized to develop the high-resolution network (HRNet)-based classification models. The ground truth was the interpretation from two experienced radiologists in consensus according to the K-L grading system. A binary-class model was trained to diagnose the presence (K-L 2∼4) or absence (K-L 0∼1) of PFOA. A multi-class model was used to grade the stage of PFOA, i.e. from K-L 0 to K-L 4. Model performances were evaluated using the receiver operating characteristics (ROC), confusion matrix, and the corresponding evaluation metrics (positive predictive value [PPV], negative predictive value [NPV], F1 score, sensitivity, specificity, accuracy) of the internal test set (n = 129) from dataset 1 and an external validation set (dataset 2, n = 187).

RESULTS

For the binary-class model, the area under the curve (AUC) was 0.91 in the internal test set and 0.90 in the external validation set. For grading PFOA, moderate to severe stage of PFOA exhibited a good performance in these two datasets (AUC = 0.91-0.98, PPV = 0.69-0.90, NPV = 0.92-0.99, F1 score = 0.72-0.87, sensitivity = 0.75-0.87, specificity = 0.90-0.99, accuracy = 0.87-0.98).

CONCLUSION

The HRNet-based approach performed well in diagnosing and grading radiographic PFOA, especially for the moderate to severe cases.

The emerging roles of N6-methyladenosine in osteoarthritis

Finding new biomarkers and molecular targets to guide OA treatment remains a significant challenge. One of the most frequent forms of RNA methylation, N6-methyladenosine (m6A), can affect gene expression and RNA transcription, processing, translation, and metabolism. Osteoarthritis (OA) can cause disability and pain degenerative disease, reduce the quality of life of the elderly, and increase the social and economic burden. Changes in m6A levels are crucial in OA progress. In this review, the discussion will concentrate on the role that m6A plays in OA occurrence and progression. The m6A involved in the OA process mainly includes METTL3 and FTO. Current studies on m6A and OA primarily focus on four signaling pathways, namely, NF-κB, LNCRNAs, ATG7, and Bcl2. m6A participates in these signaling pathways and affects cellular inflammation, apoptosis, senescence, and autophagy, thus controlling the OA process. The modification of m6A affects so many signaling pathways. For the treatment of OA, it may represent a viable new therapeutic target.

Epidemiology of osteoarthritis

OBJECTIVE

To summarize the current state of the evidence regarding osteoarthritis (OA) prevalence, incidence and risk factors at the person-level and joint-level.

DESIGN

This was a narrative review that took a comprehensive approach regarding inclusion of potential risk factors. The review complements prior reviews of OA epidemiology, with a focus on new research and emerging topics since 2017, as well as seminal studies.

RESULTS

Studies continue to illustrate the high prevalence of OA worldwide, with a greater burden among older individuals, women, some racial and ethnic groups, and individuals with lower socioeconomic status. Modifiable risk factors for OA with the strongest evidence are obesity and joint injury. Topics of high interest or emerging evidence for a potential association with OA risk or progression include specific vitamins and diets, high blood pressure, genetic factors, metformin use, bone mineral density, abnormal joint shape and malalignment, and lower muscle strength/quality. Studies also continue to highlight the heterogenous nature of OA, with strong interest in understanding and defining OA phenotypes.

CONCLUSIONS

OA is an increasingly prevalent condition with worldwide impacts on many health outcomes. The strong evidence for obesity and joint injury as OA risk factors calls for heightened efforts to mitigate these risks at clinical and public health levels. There is also a need for continued research regarding how potential person- and joint-level risk factors may interact to influence the development and progression of OA.

Novel Insights Into the Multifaceted Functions of RNA n6-Methyladenosine Modification in Degenerative Musculoskeletal Diseases

N⁶-methyladenosine (m⁶A) is an important modification of eukaryotic mRNA. Since the first discovery of the corresponding demethylase and the subsequent identification of m⁶A as a dynamic modification, the function and mechanism of m⁶A in mammalian gene regulation have been extensively investigated. “Writer”, “eraser” and “reader” proteins are key proteins involved in the dynamic regulation of m⁶A modifications, through the anchoring, removal, and interpretation of m⁶A modifications, respectively. Remarkably, such dynamic modifications can regulate the progression of many diseases by affecting RNA splicing, translation, export and degradation. Emerging evidence has identified the relationship between m⁶A modifications and degenerative musculoskeletal diseases, such as osteoarthritis, osteoporosis, sarcopenia and degenerative spinal disorders. Here, we have comprehensively summarized the evidence of the pathogenesis of m⁶A modifications in degenerative musculoskeletal diseases. Moreover, the potential molecular mechanisms, regulatory functions and clinical implications of m⁶A modifications are thoroughly discussed. Our review may provide potential prospects for addressing key issues in further studies.

[Expert consensus on surgical treatment of patellofemoral osteoarthritis]

Patellofemoral osteoarthritis (PFOA) is one of the most common causes of anterior knee pain in middle-aged and elderly population. In general, elementary therapy and drug therapy are the preferred choices for PFOA management. However, for those who cannot achieve satisfactory effectiveness with standard non-surgical treatment, surgical therapy stands as an alternative treatment. The surgical therapy includes repair surgery and reconstruction surgery. The choice of surgical plans for PFOA management mainly depends on the etiology, pathogenesis, location, and severity of the lesions. To aid clinical decision-making, the National Clinical Research Center for Geriatric Disorders (Xiangya Hospital) and the Joint Surgery Branch of the Chinese Orthopedic Association arranged nationwide orthopedic specialists to set up a work panel. After reviewing the research progress of surgical therapy and the latest guidelines and consensus for PFOA management, the work panel discussed repeatedly to reach this consensus. The present consensus aims to provide valid evidences for clinical practices of the surgical therapy of PFOA, so as to avoid inappropriate and irregular treatment behaviors, reduce surgical trauma, improve surgical efficacy and the quality of life, and to ease the burden of PFOA.