Knee Osteoarthritis Grading Using Deep Learning: Review

Abdulkader Helwan
4 min readDec 30, 2023

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Knee osteoarthritis (OA) is a common joint disease that causes pain, deformity, and dysfunction in the bones, joint membranes, and surrounding ligaments that form joints due to gradual damage or degenerative changes in the articular cartilage. Knee OA is one of the leading causes of disability in the elderly and is the most common form of OA[1]. The standard method for measuring the severity of knee OA using X-ray images is the Kellgren – Lawrence (KL) grading system, which uses five grades ranging from 0 to 4 according to severity[2].

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Review

In recent years, deep learning has shown promising results in interpreting radiographic images for the diagnosis of knee OA[2]. Several studies have employed deep neural networks in automatically predicting KL grade from plain knee joint radiographs[1–6]. However, these studies treat KL grading as a multi-class classification task and ignore the inherent ordinal nature within the KL grades [6]. In this study, the authors proposed an ordinal regression module for neural networks to treat KL grading as an ordinal regression task. Their module takes input from a neural network and produces 4 cut-points to partition the prediction space into 5 respective KL grades. The proposed model is optimized by a cumulative-link loss function.

Challenges Facing KOA Grading Using Deep Learning

Despite the promising results, creating a good model for knee OA grading system using deep learning is challenging. One of the main challenges is the lack of large-scale datasets with accurate annotations[7]. Another challenge is the presence of visual disturbances such as implants, casts, and non-degenerative pathologies, which can affect the accuracy of the model. Moreover, the KL grading system depends on the clinician’s subjective assessment, and the accuracy varies significantly depending on the clinician’s experience [8]. Therefore, developing a model that can predict a consistent and accurate KL grade for knee OA severity using a deep learning approach is crucial.

Suggestions to Help in Solving KOA Grading

In my opinion, the latest deep learning models and transformers can help solve this problem. For instance, ensemble deep-learning networks have been developed to predict a consistent and accurate KL grade for knee OA severity using a deep-learning approach. Transfer learning-assisted 3D deep learning models have also been used for knee OA detection[13]. Moreover, pre-trained SOTA deep learning models including ConvNeXt and ConvNeXt V2 have been fine-tuned using the ordinal loss function for automatic detection of knee OA stages according to the KL grading system[11]. These models have shown promising results and can be further improved by using large-scale datasets with accurate annotations and by developing models that can handle visual disturbances.

Another potential concept for solving KOA Grading problem can be the Mixture of experts (MoE). This can be a promising approach for knee osteoarthritis (KOA) grading system using deep learning. MoE is a neural network architecture that combines multiple sub-networks, each of which specializes in a different part of the input space. MoE has been used for various medical image analysis tasks, including segmentation, classification, and detection. MoE can be used to handle the ordinal nature of the KL grading system by partitioning the prediction space into multiple regions, each of which corresponds to a different KL grade.

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In short, MoE is a promising approach for KOA grading system using deep learning. It can be used to handle the ordinal nature of the KL grading system by partitioning the prediction space into multiple regions, each of which corresponds to a different KL grade. However, further research is needed to evaluate the effectiveness of MoE for KOA grading system..

Lastly, deep learning has shown promising results in interpreting radiographic images for the diagnosis of knee OA. However, creating a good model for knee OA grading system using deep learning is challenging due to the lack of large-scale datasets with accurate annotations, the presence of visual disturbances, and the subjective nature of the KL grading system. The latest deep learning models and transformers can help solve this problem by using large-scale datasets with accurate annotations and by developing models that can handle visual disturbances.

References

(1) Ensemble deep-learning networks for automated osteoarthritis grading in …. https://www.nature.com/articles/s41598-023-50210-4.pdf.

(2) Exploring deep learning capabilities in knee osteoarthritis case study …. https://ieeexplore.ieee.org/abstract/document/8900714.

(3) Osteo-Doc: KL-Grading of Osteoarthritis Using Deep-Learning. https://ieeexplore.ieee.org/document/9787470.

(4) Knee osteoarthritis severity classification with ordinal regression …. https://link.springer.com/article/10.1007/s11042-021-10557-0.

(5) Knee arthritis severity measurement using deep learning: a publicly …. https://arxiv.org/abs/2203.08914.

(6) Transfer learning-assisted 3D deep learning models for knee …. https://www.frontiersin.org/articles/10.3389/fbioe.2023.1164655/full.

(7) Automatic Detection of Knee Osteoarthritis Severity with SOTA Deep …. https://ieeexplore.ieee.org/document/10223879/.

(8) Automating classification of osteoarthritis according to Kellgren …. https://bmcmusculoskeletdisord.biomedcentral.com/articles/10.1186/s12891-021-04722-7.

(9) A Modified Comprehensive Grading System for Murine Knee Osteoarthritis …. https://www.biorxiv.org/content/10.1101/2021.05.05.442864v1.

(10) Automated grading of knee osteoarthritis X-ray images based on …. https://ieeexplore.ieee.org/document/9669623/.

(11) Toward automatic quantification of knee osteoarthritis severity using …. https://link.springer.com/article/10.1007/s11548-019-02096-9.

(12) Improved Prediction of Knee Osteoarthritis by the Machine … – Springer. https://link.springer.com/article/10.1007/s43465-023-00936-0.

(13) Hybrid Techniques of X-ray Analysis to Predict Knee Osteoarthritis …. https://www.mdpi.com/2075-4418/13/9/1609/html.

(14) A Modified Comprehensive Grading System for Murine Knee Osteoarthritis …. https://www.biorxiv.org/content/biorxiv/early/2021/05/06/2021.05.05.442864.full.pdf.

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