MR-IMAGING OF BAKER CYSTS - ASSOCIATION WITH INTERNAL DERANGEMENT, EFFUSION, AND DEGENERATIVE ARTHROPATHY

PURPOSE: To determine the prevalence of Baker cyst in a general orthop edic population and its association with effusion, internal derangemen t, and degenerative arthropathy. MATERIALS AND METHODS: Reports of 400 knee magnetic resonance imaging examinations were reviewed. Presence of Baker cyst effusion, internal derangement (meniscal and/or anterior cruciate ligament tears), medial collateral ligament injury, and dege nerative arthropathy was recorded. Uni- and multivariate logistic regr essions were used to evaluate associations between Baker cyst and thes e conditions. Probabilities of having a Baker cyst given these conditi ons were also calculated. RESULTS: No association was found between Ba ker cyst and anterior cruciate ligament tear or medial collateral liga ment injury. There were significant associations (P <.001) with effusi on, meniscal tear, and degenerative arthropathy. There were also signi ficant associations (P <.01) for effusion, meniscal tear, and degenera tive arthropathy, independent of one another. Probability of having Ba ker cyst given the presence of any one variable was .08-.10; any two v ariables, .19-.21; and all three variables, .38. CONCLUSION: The assoc iation between Baker cyst and joint effusion was confirmed. A relation ship with meniscal tear and degenerative joint disease independent of effusion was also demonstrated. The probability of having a Baker cyst increases as the number of these associated conditions increases.