Background/Purpose: Meniscal tears are a key player in knee osteoarthritis (OA) and family history of the disease has been shown to play an important role. However, there is limited longitudinal data on the natural history of meniscal tears. The aim of this study was to track natural history of meniscal tears over 8 years, describe the association with change in pain and describe structural and non-structural predictors of change in meniscal tears.

Methods: 220 participants [mean age 47 (28-63); 57% female] were studied at baseline and 8 years. Approximately half were the adult offspring of subjects who had a knee replacement performed for knee OA and the remaining half were randomly selected controls without a family history of OA. Meniscal tears were evaluated, using T-1 weighted fat saturated MRI, on a 0-2 (0=absence; 1=simple; 2=complex tear) scale within 6 defined regions: anterior horn, body, and posterior horn at both medial and lateral menisci. Cartilage volume/defects, bone marrow lesions (BMLs), meniscal extrusion and effusion were assessed on MRI and joint space narrowing (JSN) and osteophytes on radiographs using standard protocols. Pain was assessed using Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC).

Results: Using updated methodology, 22% of the participants had a meniscal tear at any site at baseline, without a significant difference between the two groups at any site. 16% of the participants had any increase in meniscal score (incident tears + increase from baseline score) over 8 years. Offspring had a significantly higher change in mean meniscal score compared to controls over 8 years (total knee score: offspring= 0.493, controls= 0.164, p=0.034). Change in meniscal tears was independently associated with worsening pain over 8 years (Table 1). There was also a significant offspring-control interaction (all p<0.05) at all sites, with offspring having a significantly higher increase in pain on WOMAC scale per unit change in tears compared to controls (Table 1). Higher BMI at baseline was independently associated with a greater risk of increase in mean meniscal score (total knee: RR= 1.10 (1.04, 1.16)). Change in total medial tears was associated with cartilage loss over 8 years in the medial (tibial + femoral) compartment (β= -176 (-302, -49)) only. Change in tears at all sites was associated with change in compartment specific and total knee BMLs (total knee: β=+0.39 (+0.26, +0.53)). Furthermore, change in tears showed the strongest independent correlation with change in both JSN (ρ=+0.37, p= <0.01) and osteophytes (ρ=+0.31, p= <0.01) in the medial compartment.

Conclusion: In this midlife cohort, meniscal tears are common. Change in tears is independently associated with change in pain, BMLs, cartilage volume and radiographic OA. In turn, change in tears is influenced by family history of OA and BMI but not history of knee injury.