Objective: Arthroscopic partial medial meniscectomy (APMM) is a common procedure to treat a medial meniscal tear. Individuals who undergo APMM have a heightened risk of developing tibio-femoral osteoarthritis (OA). Cartilage defects scored from magnetic resonance imaging (MRI) scans predict cartilage loss over time. It is not known whether cartilage defects in the early years following APMM are more common or of greater severity than in age-matched controls. This study compared the prevalence and severity of tibio-femoral cartilage defects in patients 3-5 years post-APMM with that of age-matched controls.Methods: Twenty-five individuals who had undergone APMM in the previous 46.9 +/- 5.0 months and 24 age-matched controls participated in this study. Sagittal plane knee MRI scans were acquired from the operated knees of patients and from randomly assigned knees of the controls and graded (0-4) for tibio-femoral cartilage defects. Defect prevalence (score of >= 2 for any compartment) and severity of the cartilage from both tibio-femoral compartments were compared between the groups.Results: The APMM group had greater prevalence (77 vs 42%, P= 0.012) and severity (4.1 +/- 1.9 vs 2.8 +/- 1.1, P = 0.005) of tibio-femoral cartilage defects than controls. Age was positively associated with tibio-femoral cartilage defect severity for APMM, r=0.523, P=0.007, but not for controls, r = 0.045, P = 0.834.Conclusion: Tibio-femoral joint cartilage defects are more prevalent and of greater severity in individuals who had undergone APMM similar to 44 months earlier than in age-matched controls. (C) 2008 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.