The Food & Drug Administration sent a warning letter to Smith & Nephew plc (NYSE:SNN) regarding quality control problems at its Tuttlingen, Germany, orthopedic plant.

Smith & Nephew failed to document certain steps regarding sterilization testing for hip-replacement components, the FDA said in its missive.

It’s the second warning for the London-based manufacturer of artificial knees and hips regarding the facility. The FDA cautioned SNN in August over the same issues, deeming SNN’s eventual response inadequate, according to the latest letter.

The warning does not affect product supply because Smith & Nephew also makes the parts at facilities in Memphis, Tenn., and Warwick, England. The sterilization process cited by the FDA is performed by a subcontractor; new procedures were put in place after the agency’s summer inspection, Smith & Nephew spokeswoman Liz Hewitt told Bloomberg.

The FDA sends warning letters to companies that run afoul of regulations for manufacturing and marketing drugs and medical devices. The warnings are not legally binding, but the watchdog agency can take companies to court if the alarms are not heeded.