Risk factors for meniscal tears: a systematic review including meta-analysis.

STUDY DESIGN Systematic review with meta-analysis. OBJECTIVES To review and critically appraise the literature for factors that increase the risk for meniscal tears. BACKGROUND Meniscal tears are an important cause of disability and time lost from work, and are associated with a 4-fold increase in the long-term risk of knee osteoarthritis. Knowledge of the risk factors that lead to meniscal tears can help to correctly diagnose knee injuries and is important to the development of prevention strategies for knee osteoarthritis. METHODS A search of the Cochrane Database of Systematic Reviews, MEDLINE, and Embase, from 1950 to January 2012, and a hand search of reference lists of all initially selected studies, without restriction on language or date of publication, were conducted. Prospective, retrospective, and case-control studies that included individuals over 16 years of age, who had no previous meniscal injuries or surgeries, were selected. A meta-analysis for 17 risk factors was performed. Where considerable heterogeneity among studies was present or the data did not provide sufficient information to perform a meta-analysis, a qualitative synthesis was conducted. RESULTS Eleven studies, with a total of 7358 participants, were selected for systematic review. Data were available for meta-analysis for 10 of the 11 studies. Qualitative analysis was conducted using data from 3 of the 11 studies. Results showed strong evidence that age (older than 60 years), gender (male), work-related kneeling and squatting, and climbing stairs (greater than 30 flights) were risk factors for degenerative meniscal tears. We also found strong evidence that playing soccer and playing rugby were strong risk factors for acute meniscal tears. Waiting longer than 12 months between the anterior cruciate ligament injury and reconstructive surgery was a strong risk factor for a medial meniscal tear but not for a lateral meniscal tear. CONCLUSION The literature indicates a number of risk factors leading to either degenerative or acute meniscal tears, with some of these factors being potentially modifiable. LEVEL OF EVIDENCE Prognosis, level 2a.