Kellgren & Lawrence grade 1 osteophytes in the knee—doubtful or definite?

The most universally accepted methods of classification of radiographic osteoarthritis (OA) is the Kellgren & Lawrence (K & L) grading system. However, there have been many criticisms of this including the grading of a doubtful osteophyte as a grade 1. We report the natural history of a given prevalent grade 1 osteophyte in a 10-year follow-up knee study. 62% of women graded at baseline with a doubtful osteophyte went on to develop true osteophytic knee OA compared with only 22% of controls with no sign of disease. So called ‘doubtful’ osteophytes appear to be ‘real’ and significantly related to OA knee and therefore cannot be ignored or classified as normal. Copyright 2002 OsteoArthritis Research Society International. Published by Elsevier Science Ltd. All rights reserved.