Editorial Commentary: Losartan May Prevent Clinically Significant Postoperative Fibrosis, but Large Database Studies May Not Provide an Answer.

Losartan and other modulators of the renin-angiotensin system have been used for their antifibrotic effects by nonsurgeons for decades when suppression of maladaptive scar deposition is helpful, such as heart failure and chronic kidney disease. Only recently have orthopaedic surgeons begun to explore whether these medications might reduce or prevent postoperative joint stiffness. The relationship between orthopaedic surgeons and fibrosis is more complicated. When immune cell recruitment, fibroblast activation, collagen deposition, and extracellular matrix remodeling occurs in a fashion we like, we call it "healing." When it occurs in a fashion we dislike, we call it "fibrosis." There is growing interest in chemoprophylaxis against postoperative fibrosis after shoulder surgery, arthroplasty, and hip arthroscopy. Limited studies examining the issue to date have produced conflicting results. Mining large databases for answers is unlikely to produce clinically meaningful results, and specific trials will be necessary to answer the question. Future research should not ignore the fact that medications other than losartan function in similar ways-and may also have antifibrotic effects.