zimmer biomet holdings , inc . 2015 form 10-k annual report notes to consolidated financial statements ( continued ) these unaudited pro forma results have been prepared for comparative purposes only and include adjustments such as inventory step-up , amortization of acquired intangible assets and interest expense on debt incurred to finance the merger . material , nonrecurring pro forma adjustments directly attributable to the biomet merger include : 2022 the $ 90