Now we're not going to give too many specifics on 20201, but he'll give you some color on what we're seeing from Q4 and, again, the impact we think that's going to have on 2021.
Certainly, I am, and on note, we said we're going to hit between 200 to 300 cumulative placements by the end of 2020.
We did realize our 2020 expectations of $100 million in gross revenue and almost $40 million in net of cannibalization revenue during the year.
And if I just look at Q4 specifically, we grew about 30% over Q3, again, even with the increased pressures of the pandemic in Q4, so very excited with what we're able to do with Avenir Complete.
And then finally for Signature ONE Planner, we demonstrated this again, strong sequential growth with registrations up nearly 25% in Q4 over Q3.
And we expect utilization to continue to expand significantly in 2021 with really a goal of having more than 50% of our shoulder procedures using pre-surgical planning.
That has not been a focus for ZB.
In fact, the spin-off transaction that we're going to do over the next year serves to de-risk if not accelerate our path to that 4% to 5% growth rate that we have talked about and our 30% operating margin profile by the end of 2023.
Net sales in the fourth quarter were $2.085 billion, a reported decrease of 1.9% and a constant currency decrease of 3.7% versus 2019.
Beginning with Asia-Pacific, the region grew 2% versus Q4 2019 with growth across all three of our largest markets of Japan, China and Australia/New Zealand.
As expected, the EMEA region was hardest hit by COVID-19, decreasing 17.5% versus 2019, with all sub-regions in decline.
Lastly, the Americas region was about flat, decreasing 0.3% compared to 2019, driven by continued COVID headwinds in Latin America, in tandem with a softening U.S. market.
Turning to our business performance for Q4, the Global Knee business declined 4.8% negatively impacted by the ongoing pressures in EMEA.
However, the U.S. Knee business continued to grow, increasing 1.8%, and Asia-Pacific Knee business returned to growth, increasing 2.9%.
Our Global Hip business decreased 3.4%, again driven by declines in EMEA.
Both U.S. Hips and APAC Hips continued their growth trends, increasing 1.4% and 1.3% respectively.
Sports, Extremity, and Trauma sales declined 3.3%.
Dental, Spine and CMFT continued to deliver better execution, increasing 0.8%, and finally, our Other category was down 9.3%.
Moving to the P&L, we reported GAAP diluted earnings per share of $1.59 and adjusted diluted earnings per share of $2.11.
On an adjusted basis, with revenue down 3.7%, earnings per share was down about 10% driven by a lower operating margin and a higher share count, which more than offset the favorable tax rate in the quarter.
Adjusted gross margin was 71.3%, sequentially better than Q3, but lower than Q4 2019.
The Q4 adjusted tax rate of 15% was better than the previous year due to geographic mix of income and certain discrete benefits in the quarter, related to recent audit settlements.
Turning to cash and liquidity in the quarter, free cash flow totaled $329 million, higher than the same period in 2019, driven by better working capital and lower capital expenditures, and we utilized better-than-expected cash flow to pay down $250 million of debt ahead of schedule, ending the year with cash and cash equivalents of approximately $800 million.
And in terms of capital allocation, we remain committed to maintaining our investment-grade rating and are planning to pay down an additional $500 million of debt in 2021.
In terms of the NewCo financial profile, 2019 and 2020 pro forma revenues totaled approximately $1.022 billion and $897 million respectively and is supported by a diversified geographic base with real opportunities for enhanced growth and margin expansion.
ZB delivered 2019 and 2020 pro forma revenue of $6.96 billion and $6.128 billion respectively.
For post-spin ZB, the transaction is expected to deliver an improved growth profile with accretion to our revenue growth of approximately 50 basis points over the course of our five-year strategic planning period.
We also expect that it will expand our adjusted EBITDA and operating margins on a pro forma basis by approximately 125 basis points.
We remain committed to at least 30% adjusted operating margins by the end of 2023, and with this transaction we have the opportunity to accelerate the timing of that goal.

Summary:
That has not been a focus for ZB.
Net sales in the fourth quarter were $2.085 billion, a reported decrease of 1.9% and a constant currency decrease of 3.7% versus 2019.
Moving to the P&L, we reported GAAP diluted earnings per share of $1.59 and adjusted diluted earnings per share of $2.11.