Radiographic assessment of osteoarthritis: analysis of disease progression

Osteoarthritis (OA) is one of the most prevalent and disabling chronic conditions affecting older adults, and is a significant public health problem among adults of working age. The knee is the most frequently involved joint site associated with disability in OA. Diagnosis of OA is primarily based on history and physical examination, but radiographic findings, including asymmetric joint space narrowing (JSN), subchondral sclerosis, osteophyte formation, subluxation, and distribution patterns of osteoarthritic changes are all helpful when diagnosis is uncertain. Structural morphological changes on X-rays are also considered the primary outcome variables for assessing the progression of OA. The development of new methods for prevention and treatment of OA requires improved understanding of the factors that influence its progression. The ability to assess progression quantitatively is a necessary first step in understanding factors that influence the disease process. Depending on the joint studied, several indices are currently used for assessing radiological progression of OA, including individual radiographic features (e.g., marginal osteophytes), composite indices (e.g., Kellgren and Lawrence scoring systems), and quantitative measures (e.g., joint space width measurement). Unfortunately, the review of studies evaluating the longitudinal rate of JSN indicates that the yearly change may be very small and of doubtful clinical significance. This emphasizes the need for further refinement in the definition of radiographic outcomes in prospective clinical trials. This review focuses on the available scoring methods used for the sites most frequently involved in OA (hand, knee, hip) and their various advantages and disadvantages.