ConforMIS (NSDQ:CFMS) has sued Zimmer Biomet  (NYSE:ZBH) alleging infringement of four different patents for personalized joint replacement surgery.

In the lawsuit filed last week in U.S. District Court in Delaware, ConforMIS claims that Zimmer Biomet has infringed its patents for personalized knee and hip replacement surgery and for shoulder arthroplasty. Bedford, Mass.-based ConforMIS is targeting Zimmer Biomet’s Vanguard, Persona, NexGen and Gender Solutions knee systems; its PSI shoulder for trabecular metal reverse glenoid and Signature personalized total and reverse shoulder systems; and its Signature acetabular guide system for hip replacement surgery.

In 2018, ConforMIS won a $10.5 million settlement in a patent infringement lawsuit against Smith & Nephew (NYSE:SNN) over technology for patient-specific knee implants. In March 2019, a federal appeals court declined a full review of its earlier decision to affirm a $248 million win for Stryker (NYSE:SYK) in its surgical tool patent case against Warsaw, Ind.-based Zimmer Biomet.

In June, ConforMIS lined up $33 million in financing for its customized joint replacement devices.