Structural features of early-stage OA: Keep your menisci in good shape

Knee osteoarthritis (OA) is a common disease in the aging population and causes a great burden to society worldwide. Identifying early OA changes and initiating interventions in OA risk populations is important. Meniscus pathologies, which include meniscal tears, meniscus extrusion, and meniscal morphometrical abnormalities, play an important role in OA development. In this thesis, we assess the role of meniscus volume in OA. We also explore several factors that are associated with meniscus volume and extrusion. In addition, we systematically review all studies that evaluated the association between PA levels and knee OA features on MRI in non-OA subjects. Meniscus volume was positively associated with incident radiographic knee OA. Varus alignment, BMI, physical activity level, and quadriceps muscle strength are modifiable factors and could be targeted in the prevention of abnormity in meniscus volume. Those non-modifiable factors such as higher age, injury, meniscus pathologies, meniscus extrusion, and cartilage lesions could provide some mechanism pathway for OA development. We found that two SNPs were associated with decreased volume in the lateral meniscus, GDF5 (rs78110303) and COG5 (rs3815148). No evidence was found that postmenopausal women have an increased risk for meniscal extrusion. Although little evidence was available, the review suggested that PA was not associated with the presence and progression of OA MRI features among non-OA subjects. With the findings in this thesis, we get a deeper insight into meniscus pathologies and OA development. The thesis provides new possibilities for the early diagnosis and prevention of knee OA.