Are these former FTSE 100 shares now brilliant contrarian buys?

With global healthcare investment set to continue steadily rising in the years ahead, I reckon ConvaTec Group(LSE: CTEC) could prove a terrific growth stock.

The medical products and technologies company -- a leader in wound care and continence products -- fell out of the FTSE 100 in November in the wake of a disastrous trading update the previous month.

Back then, ConvaTec chopped down its full-year revenues forecasts on the back of disappointing performances from its new products, in addition to supply delays, the latter predicted to cancel out previous margin improvements. The firm printed a painful daily share price loss of 28% on the back of the news.

The business failed to snap back until Thursday's bright, full-year trading statement, the share last trading 8% higher and at four-month peaks. I reckon this could prove a significant moment in the company's investment story.

Bag it up

ConvaTec declared today that while the impact of the aforementioned supply problems will seep over into the current year, sales managed to beat expectations last year.

Group revenues rose 4.5% in 2017 to $1.76bn, although this was not enough to stop adjusted pre-tax profit from falling 3.3% year-on-year to $456.8m. ConvaTec attributed the result to "increased investment in growth" on top of the cost of listing the company in 2016.

Investors cheered news that revenues on an organic basis rose 2.3% in the last fiscal period, beating the company's revised predictions of a 1-2% advance put out last year.

But ConvaTec is predicted to see earnings expansion cool from recent years. That's due, in part, to lost orders related to last year's supply problems as well as the firm's attempts to tackle the resultant backlogs, both of which will continue during the first half of 2018, it noted.

That said, a predicted 14% rise for 2018 is nothing to be scoffed at. And the medical mammoth is expected to print a further 9% advance next year.

In my opinion, ConvaTec's long-term profits outlook remains a compelling one and last year's manufacturing problems, also in my opinion, will represent nothing more than a bump in the road.

I reckon a forward P/E ratio of 15 times represents an attractive level at which to tap into the FTSE 250 firm's compelling earnings picture.

Not such a hot stock...

I'm not so optimistic over the earnings prospects of Merlin Entertainments (LSE: MERL).

The Alton Towers owner -- which was also kicked out of Britain's blue chip index at the end of last year -- has fallen out of favour with share pickers. That came after announcing in October that like-for-like revenues had flatlined during the 40 weeks to October 7 due to "the series of terror attacks and unfavourable weather" during the period.

These troubles have led City analysts to predict that Merlin's earnings will have fallen 3% in 2017, a rare dip if realised.

Now while City analysts are predicting that Merlin will return to earnings growth straight away (rises of 5% and 10% are estimated for 2018 and 2019, respectively), I'm not convinced as the issues that were prevalent in 2017 are in danger of continuing for much longer.

And I believe a prospective P/E ratio of 15.9 times is a little too high given these problems.

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Royston Wild has no position in any of the shares mentioned. The Motley Fool UK has no position in any of the shares mentioned. Views expressed on the companies mentioned in this article are those of the writer and therefore may differ from the official recommendations we make in our subscription services such as Share Advisor, Hidden Winners and Pro. Here at The Motley Fool we believe that considering a diverse range of insights makes us better investors.