IP Law Daily, PATENT—Fed. Cir.: $20 million jury verdict in knee surgery patent infringement lawsuit vacated on appeal, (Oct 7, 2025)

By Saurabh Kashyap, B.A., M.A., LL.B., LL.M.

Plaintiff lacked ownership of asserted patents when filing the initial lawsuit; prior assignment to a third party rendered the suit jurisdictionally defective.

In a non-precedential disposition, the U.S. Court of Appeals for the Federal Circuit vacated a $20 million jury verdict and accompanying injunction awarded to Rasmussen Instruments, LLC, in a knee surgery device patent suit against DePuy Synthes Products, Inc. The court held that Rasmussen lacked Article III standing because it did not own either of the two asserted patents at the time the suit was filed (Rasmussen Instruments, LLC v. Depuy Synthes Products, Inc., No. 23-1855 (Fed. Cir. Oct. 6, 2025)).

Background. The plaintiff/cross-appellant, Rasmussen Instruments, LLC, is a medical device company founded in 2020 by orthopedic surgeon Dr. G. Lynn Rasmussen, specializing in joint replacement instrumentation. The company develops and markets surgical tools for knee replacement procedures. The defendants/appellants, DePuy Synthes Products, Inc. and DePuy Synthes Sales, Inc., subsidiaries of Johnson & Johnson, manufacture and sell orthopedic implants and surgical instruments. A related entity, Medical Device Business Services, Inc., was also named in the suit.

Rasmussen alleged infringement of U.S. Patent Nos. 9,492,180 (the ’180 patent) and 10,517,583 (the ’583 patent), both listing Dr. Rasmussen as inventor. The patents cover instruments used during total knee replacement surgery—the ’180 patent concerning an improved ligament tensioning device, and the ’583 patent covering modular instrument enhancements.

In 2006, Dr. Rasmussen entered into a Development and Licensing Agreement with Wright Medical, assigning all “inventions” and “know-how” related to his “Zen Instrument” and any future improvements. The agreement stated that Wright “shall be the sole owner” of the product and that Dr. Rasmussen “hereby assigns” all rights to Wright. A 2013 Settlement and License Agreement ended their collaboration but did not return intellectual property rights to Dr. Rasmussen.

In 2018, Dr. Rasmussen met with DePuy to discuss possible collaboration, but no deal was reached. Two years later, he formed Rasmussen Instruments and assigned the patents to it, which then sued DePuy in October 2020. A 14-day jury trial took place in early 2022 in the District of Massachusetts. The jury found that DePuy willfully infringed the '180 patent, awarded $20 million in damages, and found no infringement of the '583 patent. It upheld the validity of both patents. The district court denied DePuy's post-trial motion for judgment as a matter of law on ownership and infringement, granted Rasmussen's request for a permanent injunction and prejudgment interest, but denied enhanced damages and attorney fees. DePuy appealed the infringement and remedies rulings, while Rasmussen cross-appealed the non-infringement judgment on the '583 patent.

Standing and ownership. The Federal Circuit identified standing as a constitutional prerequisite for jurisdiction under Lujan v. Defenders of Wildlife, 504 U.S. 555, 560–61 (1992) and noted that a plaintiff must own the asserted patent on the filing date of the complaint.

Court’s analysis. The court conducted a de novo review, as the material facts were undisputed. It held that under 35 U.S.C. § 261, patent assignments must be in writing and transfer either the full right, an undivided interest, or exclusive territorial rights.

2006 agreement. The Federal Circuit found that Dr. Rasmussen’s 2006 agreement used present-tense language—“hereby assigns”—which automatically and immediately conveyed patent ownership to Wright. Citing Speedplay, Inc. v. Bebop, Inc., 211 F.3d 1245, 1253 (Fed. Cir. 2000), and Bd. of Trs. of the Leland Stanford Junior Univ. v. Roche Molecular Sys., Inc., 583 F.3d 832, 842 (Fed. Cir. 2009), the court held that this phrasing effected a self-executing transfer requiring no further action. Because the “Licensed Product” listed in the contract—the ADVANCE® Intra-Operative Knee Tensioner—was identical to the Zen Instrument, Wright became the exclusive owner of all inventions and subsequent improvements related to it.

2013 agreement. Rasmussen argued that the 2013 Settlement Agreement “recast” the parties’ rights and effectively restored ownership to Dr. Rasmussen nunc pro tunc. The Federal Circuit rejected this argument, noting that the 2013 documents deleted certain product references but contained no language reassigning patents. The court held that “broad language purporting to modify or restate rights” does not override a prior written assignment absent an explicit reassignment clause. Citing Jim Arnold Corp. v. Hydrotech Sys., Inc., 109 F.3d 1567, 1577 (Fed. Cir. 1997), the panel emphasized that assignments may only be undone by express contractual terms or operation of law—not by implication or “retroactive effect.”

Rasmussen also urged the court to consider Wright's post-agreement conduct and the parties' course of dealing as evidence that ownership had reverted. The Federal Circuit dismissed this contention, explaining that extrinsic evidence cannot contradict an unambiguous contract. Under the Tennessee and Utah versions of the Uniform Commercial Code, clear written terms prevail over course-of-performance evidence. The panel added that "nunc pro tunc” simply denotes retroactive effect and cannot revive extinguished property rights without a formal reassignment.

Scope of assignment. The appellate court also addressed Rasmussen’s argument that the 2006 assignment did not cover “after-acquired” patents such as the ’180 and ’583 patents. The panel rejected this, holding that the contract’s broad definitions of “Inventions” and “Know-How”—covering “improvements, modifications, enhancements, and later variations”—swept in all derivative patents related to the Zen Instrument. Relying on Regents of the Univ. of New Mexico v. Knight, 321 F.3d 1111, 1120 (Fed. Cir. 2003), the court found this language sufficient to convey ownership of all subsequent filings and applications linked to the original device.

The Case is No. 23-1855.

Judge: Hughes, T.

Attorneys: Kurt Louis Glitzenstein (Fish & Richardson PC) for Rasmussen Instruments, LLC. Gregory A. Castanias (Jones Day) for Depuy Synthes Products, Inc. and Depuy Synthes Sales, Inc.

Companies: Rasmussen Instruments, LLC.; Depuy Synthes Products, Inc.; Depuy Synthes Sales, Inc.

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