It's no secret that in-person medical appointments are hard to come by in the age of COVID-19. But now that the U.S. appears to be getting the pandemic under control, people are eagerly flocking back to the clinic for everything they've put off, from dental cleanings to heart surgery. 

Okay, perhaps some aren't exactly thrilled to be catching up on their deferred healthcare, but the ongoing influx of business is certainly going to drive the next few quarters of earnings across the industry. And, luckily for investors, there is a pair of reliable and rapidly growing medical device companies that are poised to benefit in a big way. Though neither of the two stocks are cheap at their present valuations, both could soar higher as life gets back on track, and that makes them worth a closer look.

Young female healthcare worker wearing scrubs stands in front of desktop computers at work.

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1. Align Technologies

When the pandemic hit, cosmetic dentistry ground to a halt, and that gave Align Technologies (NASDAQ:ALGN) a rough start to 2020. The company makes the Invisalign brand of transparent tooth straighteners, each of which is individually shaped to fit for all of its nine million patients by an army of nearly 190,000 expert orthodontists.

In the second quarter of 2020, it moved only 221,900 cases of its straighteners, compared to 359,400 cases in the prior three months. While its business quickly recovered and ended the year on a high note of 568,000 cases sold in the final quarter, there's no way around the fact that patients need to attend in-person consultations with their doctor before starting to use teeth aligners. 

Worldwide, Align only grew its volume of shipments by 13.3% in 2020. That's a sharp drop from its growth of 34% in 2019 and 45% in 2018. So, as more and more people get vaccinated and start to be more willing to initiate consultations to start their tooth straightening treatment, it's highly likely that sales growth will return to the steep upward trajectory that it was on before the pandemic.

That's especially probable given the company's new advertising and consumer outreach campaigns in its high-growth markets like Germany. For investors seeking a reliable growth stock that's approaching its prime, it's hard to go wrong with Align.

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2. Abiomed

As a result of chaos in the second quarter of last year, heart pump manufacturer Abiomed (NASDAQ:ABMD) took a major performance hit, with its total revenue growing by only 9%, reaching $841 million. With people staying at home and deferring nonessential activities, there aren't as many opportunities for them to get into the kind of medical trouble that might require mechanical support for their heart.

Now that nonessential surgeries are resuming and hospital capacity is no longer scarce, the company is ready to return to its prior rate of growth. From 2017 to 2019, its total revenues grew between 30% and 35% each year -- and in the near future, that could accelerate for two key reasons. 

The first reason is that in June 2020, Abiomed's Impella pumps received emergency approval to be used in patients who are experiencing heart failure as a result of COVID-19 infections. Given that the virus can cause heart issues in many people, the newly approved indication is an entirely new market for the company's products, though it remains to be seen how large the opportunity will be in the long term. 

The second reason that investors should be bullish about Abiomed's future is that management has been diligent in continuing to invest in future opportunities during the doldrums of the pandemic. The company recently initiated a new clinical trial investigating whether its Impella heart pump is suitable for use in high-risk percutaneous coronary interventions, a class of heart surgeries.

The trial builds on previous studies of the Impella that showed a 29% reduction in adverse outcomes like death, heart attacks, and strokes in the 90 days after being treated. If it is successful in the ongoing study, it'll expand the addressable market for its pumps significantly, and revenue growth will be sure to follow. Still, it could be a few years until the trial and the regulatory paperwork are complete, so investors should set their expectations accordingly.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.