Background Knee osteoarthritis (OA) is commonly associated with joint pain at multiple sites 1,2. Whether this pain is associated with cartilage loss in the knee is unknown.
Objectives To determine whether joint pain at multiple sites is a predictor of cartilage loss in the knee amongst older community–dwelling adults and whether this reflects more severe disease or shared risk factors.
Methods Data from the prospective Tasmanian Older Adult Cohort study (n=394; mean age, 63 years; range from 52 to 79) was used. Pain experience in the different joints was measured by a questionnaire at baseline. T1-weighted fat saturated MRI of the right knee was performed to assess the cartilage volume at baseline and after 2.7 years. Linear regression modelling was used with adjustment for potential confounders.
Results The median number of painful sites was 3 (range from 0 to 7). Participants reporting more painful joints had greater cartilage volume loss at lateral and total but not medial tibiofemoral compartments. A strong linear relationship between number of painful joints and cartilage volume loss at lateral tibiofemoral and total compartments was observed in univariate analysis, and remained significant in multivariate analysis (β = -0.28% to -0.25% per annum, P<0.05 for all comparisons). In subgroup analyses, there was a dose-response relationship for lateral and total tibiofemoral cartilage volume loss with increasing number of painful joints (all adjusted P for trend<0.05) in participants without radiographic OA. These significant associations were independent of severity of knee pain or radiographic OA, knee structures and body mass index as well as other potential confounding factors. However, no significant associations were found in any compartments for participants with radiographic OA.
Conclusions The number of painful joints independently predicts cartilage volume loss especially in people without radiographic OA, suggesting that widespread joint pain may be a marker of risk for more rapid early cartilage loss possibly mediated by systemic, central or genetic factors.
Dieppe PA, Lohmander LS. Pathogenesis and management of pain in osteoarthritis. Lancet 2005;365:965-73.
Malfait AM, Schnitzer TJ. Towards a mechanism-based approach to pain management in osteoarthritis. Nat Rev Rheumatol 2013;9:654-64.
Disclosure of Interest None declared