The U.S. Internal Revenue Service on Wednesday released final rules for a new tax on medical devices, products ranging from surgical sutures to knee replacement implants, that starts next year as part of President Barack Obama's 2010 healthcare law. The 2.3-percent tax must be paid, effective after December 31, by device-makers on their gross sales. The tax is expected to raise $29 billion in government revenues through 2022. The tax applies mostly to devices used and implanted by medical professionals, including items as complex as pacemakers or as simple as tongue depressors.