Oral Losartan to Decrease the Risk of Postoperative Arthrofibrosis Following Primary and Revision Anterior Cruciate Ligament Reconstruction

Losartan, an angiotensin-II receptor blocker (ARB), approved by the Food and Drug Administration (FDA) for the treatment of hypertension and diabetic nephropathy, has garnered recent interest in the field of orthopedic surgery as an anti-fibrotic (anti-scarring) agent. Losartan's primary mechanism of action as an anti-hypertensive involves acting as a receptor antagonist for angiotensin II, a peptide produced by the liver which causes vasoconstriction, release of anti-diuretic hormone from the pituitary gland, and release of aldosterone from the adrenal glands, among other functions. Losartan secondary function is to act as a TGF-β1 blocker. TGF-β1 has been implicated in pro-fibrotic pathways in multiple organs systems. Losartan, initially as a treatment for hypertension and diabetic nephropathy, was found to have benefits against fibrosis in the renal system. As a result, the use of losartan has gained interest in several other fields in medicine, including plastic surgery for wound healing and keloid prevention, in ophthalmology to prevent corneal scarring, and orthopedic surgery. The potential use of losartan presents an attractive anti-fibrotic prophylaxis candidate against the formation of postoperative arthrofibrosis following ACLR.