The prevalence of articular cartilage changes in the knee joint in patients undergoing arthroscopy for meniscal pathology

Purpose: The purposes of this study were to evaluate the prevalence of articular cartilage changes in the knee joint and to analyze predictive factors for these changes in patients undergoing arthroscopy for meniscal pathology. Methods: Between March 2005 and June 2009, 1,010 patients underwent arthroscopic meniscectomy or meniscal repair by the senior author. During surgery, a precise diagram was used to carefully note the presence, location, size, and Outerbridge grade of changes to the articular surfaces of the knee joint. The prevalence of articular cartilage changes was calculated for 6 age groups: younger than 20 years, 20 to 29 years, 30 to 39 years, 40 to 49 years, 50 to 59 years, and 60 years or older. Demographic data including gender, ethnicity, smoking status, and body mass index (BMI) were acquired from patient charts. Results: Overall, 48% of patients showed changes to the medial compartment, 25% to the lateral compartment, and 45% to the patellofemoral compartment. Eighty-five percent of patients aged 50 to 59 years and 86% of patients aged 60 years or older showed articular cartilage changes to at least 1 knee compartment. In contrast, only 13% of patients aged younger than 20 years and 32% of patients aged 20 to 29 years showed changes to at least 1 compartment. A significant relation was found between age and the development of articular cartilage changes in each of the 3 compartments (P <.0001). BMI was also significantly related to articular cartilage changes in the medial and patellofemoral compartments (P <.0001) but not the lateral compartment (P =.08). Conclusions: This study shows a high prevalence of articular cartilage damage as defined by the Outerbridge classification in patients undergoing arthroscopic surgery for meniscal pathology. Risk factors that correlate with articular cartilage damage include increasing age, elevated BMI, medial compartment pathology, and knee contractures. Level of Evidence: Level IV, therapeutic case series.