Loss of anterior cruciate ligament integrity and the development of radiographic knee osteoarthritis: A sub-study of the osteoarthritis initiative

Introduction: The aim of this study was to determine whether loss of ACL integrity in an older cohort precedes the onset of radiographic OA (ROA). Methods: Participants in this nested case-control study were selected from the Osteoarthritis Initiative (OAI) study who had risk factors for OA development but did not have ROA (Kellgren-Lawrence grading (KLG) of 0 or 1) in both knees at baseline. The MRIs were assessed for the presence of ACL tears. Case knees were defined by the development of ROA on knee radiographs between the 12 and 48 month visits. Their radiographs were assessed at P0 (time of onset of radiographic knee OA), 1 year prior to P0 (P-1) and at baseline. Controls were selected from amongst those who did not develop incident ROA and were matched to cases. Results: 355 persons who developed ROA were matched to 355 controls. No relationship between loss of ACL integrity and incident ROA was found at any assessment time point. Odds ratios (OR) for baseline, 1year prior to incident ROA (P1) and at point of occurrence of incident ROA (P0) were 2.00 (0.66-6.06), 2.5 (0.76-8.24) and 2.75 (0.85-8.88) respectively. A significant risk of incident ROA was found in participants who had a history of knee injury with an OR of 1.51 (1.05-2.16). Conclusion: Loss of ACL integrity does not confer a significantly increased risk of incident ROA in an older adult cohort. In contrast, a history of knee injury was associated with an increased risk of incident ROA.