抄録
Introduction: Objective assessment of disease severity of osteoarthritis of the knee joint (OA knee) is fundamental to establish adequate treatment system. Regrettably, there is no such a reliable system. Grading system based upon X-ray findings or measurement of joint space narrowing is widely used method for this purpose but they are still far from satisfaction. Our previous study elucidated that measuring irregularity of the contour of the femoral condyle on MRI (irregularity index) using newly developed software enabled us to assess disease severity of OA objectively. Advantages of this system are expressing severity by metric variable and semi-automatic character. In the present study, we examined relationship between treatment selection and irregularity index.
Material and Methods: Sixty-one medial type OA knees that received total knee arthropaslty (TKA), arthroscopic surgery (AS), and conservative treatment (CT) were involved. Their x-ray grading, irregularity index were recorded at the time of corresponding treatment. Irregularity index of each group were compared. As for AS group, pre- and post-operative knee score employing JOA score were also examined to study relationship between irregularity index and improvement of knee score.
Results: 1) All the four parameters that represent irregularity of femoral condyle were significantly higher in TKA group than in AS group, whereas no significant difference was observed between AS group and CT group.2) Negative correlation was observed between irregularity index and improvement of knee score after arthroscopic surgery.
Discussion: Although treatment selection was determined by skillful knee surgeon in this series, irregularity index could indicate adequate timing of TKA. It also served as an indicator to predict outcome of arthroscopic surgery, and could be used as to show limitation of arthroscopic surgery.
Conclusion: Our new system to assess disease severity of OA knee can serve as an index to determine treatment options.
