To the Editors:

I appreciate the interest shown by Drs. Shin and Lee. I agree with their observations that the data on the effects of various MMPs in tendon injury are inconclusive at best, as referenced by the authors (1–3). Also, there are no studies to explore the direct effects of statins on MMP levels, and this theory is based on circumstantial evidence. However, I would like to highlight that tendon metabolism is a dynamic process and that any interference with metabolism, i.e., raising or lowering levels of MMPs, is likely to predispose to tendon damage (4). The theory of statins affecting eicosanoid metabolism leading to tendon injury is also tenable. More studies at a molecular level would be appropriate to find possible etiologies for statins leading to tendon rupture. However, before we embark on hypothesizing etiologies for effects of statins on tendon metabolism, we must remember that there is no comparative study to show that statins cause tendon rupture. A single case series and a few cases can by no means be used to judge causality (5). Future epidemiologic studies will help clarify the relationship between statins and tendon rupture.

Abhimanyu Beri MD*, * Michigan State University, East Lansing, MI.