A federal judge in Texas shot down a salvo fired by Kinetic Concepts Inc. (KCI) in its wound care war with Smith & Nephew (SNN), denying KCI’s motion to bar its British competitor from marketing negative pressure wound therapy kits using foam dressings.

KCI sued Smith & Nephew for patent infringement, alleging that its Renasys-F foam dressing kits violated a pair of KCI patents. The San Antonio, Texas-based wound care firm wanted Judge Royal Fergeson of the U.S. District Court for Western Texas to enjoin Smith & Nephew from selling any NPWT kits using the Renasys dressing.

But Fergeson ruled that Smith & Nephew raised “a substantial question regarding whether their device contains each element” of the disputed patents, as would be required if a preliminary injunction were to be granted.

The judge also noted Smith & Nephew’s contention that a U.S. Patent and Trademark Office decision upholding KCI’s patents was flawed.

“Additionally, [Smith & Nephew’s lawyers] have raised several issues regarding the validity of KCI’s patents,” Fergeson wrote. “After reviewing the entire record, the Court is unable to conclude whether KCI will likely succeed on the issue of validity. While the patents’ successful reexamination is strong evidence of validity, [Smith & Nephew’s lawyers] have raised substantial questions regarding whether the PTO’s determination of validity was based on flawed claim construction.”

It’s the latest episode in a long-running battle over the wound care technology that has seen each side notch victories. KCI won decisions in the U.S. and Australia, while the British conglomerate won decisions in Germany and the United Kingdom over equivalent intellectual property.