Changes in patellofemoral bone marrow lesions and knee pain: Natural history and the associations with structure

Abstract

s / Osteoarthritis and Cartilage 23 (2015) A82eA416 A298 2. IGF-II is capable of promoting cartilage matrix maintenance in injuryinduced OA in mice and in human OA cartilage ex vivo cultures. 469 CHANGES IN PATELLOFEMORAL BONE MARROW LESIONS AND KNEE PAIN: NATURAL HISTORY AND THE ASSOCIATIONS WITH STRUCTURE Z. Zhu y, C. Ding y, X. Jin y, B. Antony y, W. Han y, L. Laslett y, F. Cicuttini z, G. Jones y. yMenzies Inst. for Med. Res., Hobart, Australia; zDept. of Epidemiology and Preventive Med., Monash Univ., Melbourne, Melbourne, Australia Purpose: Bone marrow lesions (BMls) are recognized as an important subchondral feature in knee OA and play a vital role in the diease progression. The patellofemoral joint (PFJ) is a common site of pain and contributes to functional limitations among OA patients. However, there are very few clinical or epidemiological studies that reveal the association between PFJ BMLs and clinical symptoms as well as cartilage structural morphologies. Meanwhile, the natural history of PFJ BMLs has not yet been described. The aims of this study were, therefore, to describe the natural history of MRI-detected BMLs in PFJ over 2.6 years and evaluate the association between increases in PFJ BMLs, knee pain and knee cartilage morphology in older adults. Methods: 406 males and females were randomly selected from local community (mean age 63 years, range 51 to 79) and followed up for 2.6 years. PFJ BMLs were determined on T2-weighted fat saturated magnetic resonance imaging (MRI) using Whole-Organ MRI Score system (WORMS). Knee cartilage volume and cartilage defects scores (0-4) were determined on T1-weighted fat suppression MRI using WORMS. Knee pain was accessed byWestern Ontario and McMaster Universities Osteoarthritis (WOMAC) scores. Student's t-tests and Pearson's c2 tests were used to compare the differences between subjects with and without an increase in PFJ BMLs. Crude and adjusted linear regression was used to determine whether PFJ BML changes over 2.5 years were associated with changes in knee pain in the different sub-scales over 5 years, before and after adjustment for potential confounders. Binary logistic regression was used to examine the associations between increases in PFJ BMLs as an outcome, and baseline cartilage volumes as well as baseline cartilage defect scores as predictors, both before and after adjustment for potential confounders. Results: At baseline, 27% (n1⁄4109) had PFJ BMLs, 24% of these showed progression (change in score of 1) at follow-up, 44% persisted and 21% completely resolved. Of those 73% (n1⁄4297) who did not have PFJ BMLs at baseline, 19.7% of them developed new PFJ BMLs over 2.6 years. In multivariable analysis, change in PFJ BMLs was positively associated with increases in total knee pain (b: 0.81, 95% CI: 0.15, 1.48) and knee pain when going up/down stairs (b: 0.29, 95% CI: 0.08, 0.50) over 5 years. While baseline patellar cartilage volume predicted a decrease in PFJ BMLs (OR: 0.62, 95% CI: 0.43, 0.90), baseline patellar cartilage defects were associated with an increase in PFJ BMLs (OR: 1.75, 95% CI: 1.28, 2.40) over 2.6 years. Tibiofemoral cartilage volume and defects were not associated with changes in PFJ BMLs. Conclusions: PFJ BMLs are not static and change is clinically relevant. An increase in PFJ BMLs can be predicted by reduced patellar cartilage volume and increased patellar cartilage defects site-specifically.