The Zimmer MDL at one time included over 1,400 plaintiffs. It currently includes approximately 500. In general, the plaintiffs have claimed that they received certain knee implants manufactured by Zimmer which “loosened” prematurely. When a knee implant loosens, it can allegedly cause difficulty walking or standing, pain and swelling, and “popping'; or “clicking” noises in the knee. Patients who experience premature loosening often need corrective surgery to remedy the issue.

In 2013, after the parties had conducted initial discovery and Zimmer had produced millions of pages of documents from over 100 custodians (and after plaintiffs had already voluntarily dismissed nine “trial ready” cases), Zimmer moved for a Lone Pine order contending that “this litigation is rampant with facially unsupportable claims that should never have survived the due diligence that plaintiffs’ attorneys must apply before filing a claim.” Zimmer identified several categories of suspect claims, including: (1) claims that appeared to be barred by the applicable statutes of limitations; (2) cases in which the plaintiff had not experienced loosening; (3) cases in which the plaintiff had not received one of the implants at issue, but rather a different implant; and (4) cases in which the plaintiff had not had corrective surgery. Zimmer asked the court to use its authority under Rule 16(c) to require plaintiffs to provide “certain basic documentation” confirming that their allegations of legally actionable injury had a reasonable basis in fact.


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