OtisMed Corporation began creating surgical tools, or rather "guides," that were intended to assist surgeons in conducting more precise and efficient knee replacements. The OtisKnee guides were marketed by the company directly to physicians and hospitals - bypassing FDA regulations and making claims about the efficacy of the devices that were not approved by the FDA. The company claimed the OtisKnee was a Class I medical device - meaning that it did not require premarket review by the FDA as it was a low risk device. Classification of devices is voluntarily made by medical manufacturers, meaning that there is opportunity for companies to mis-classify and bypass FDA regulation. The FDA was tipped off to the OtisKnee misclassification in 2008 when Stryker planned to purchase OtisMed for $100 million. The FDA notified the company that the OtisKnee guides were a Class III device, requiring extensive testing to ensure they were safe for consumers. The OtisKnee had already been distributed, however, and more were shipped to physicians even after the FDA stepped in. Some phyisicians noticed malfunctions early on when they began using the OtisKnee, while others contended that the guides allowed them to provide custom knee replacements with faster recoveries and less pain. Several lawsuits have been filed against OtisMed and physicians who used the devices. It is unknown how many patients were negatively affected by the OtisKnee guides.