San Diego-based KFx Medical, the venture-backed developer of medical devices used for orthopedic surgery, said this week that it has launched a patent infringement suit against a competitor, Arthrex. KFx medical alleges that Arthrex is infringing on a patent (U.S. Patent No. 7,585,311) covering knotless double row rotator cuff repair. Rotator cuff injuries are common in baseball players and other athletes. KFx Medical said the patent lawsuit was a result of a re-examination of it patent--requested by an anonymous party--which was rejected by the U.S. Patent Office, upholding the firm's patent. KFx Medical is being represented by Knobbe, Martens, Olson & Bear, LLP in the lawsuit. KFx Medical is venture backed by Alloy Ventures, Arboretum Ventures, Charter Life Sciences, MB Venture Partners and Montreux Equity Partners.