After a horrendous 2012, things are finally looking up for robotic surgery specialist MAKO Surgical (UNKNOWN:MAKO.DL); less than two weeks ago during its fourth-quarter and full-year 2012 earnings report, MAKO was thankfully able to answer a few of the key questions frustrated investors were asking.

Even so, I still enjoy poking and prodding my way deeper into the businesses underneath the stocks I own. After all, while it's smart to know your investments, even investing great Peter Lynch -- who is best known for his "buy what you know" mantra -- called for investors to maintain an intimate knowledge of their holdings, saying "Unfortunately, buying stocks on ignorance is still a popular American pastime."

Innovative implants
As it stands, MAKO's RIO system guidance called for relatively flat year-over-year sales of between 45 and 48 systems in 2013. Until these numbers manage to pick up, then, we can be sure MAKO will be focusing plenty of attention on growing procedures with its existing customer base.

And that, my fellow Fools, is where MAKO's much-heralded total hip arthoplasty, or THA, solution comes into play, and why I decided it might be useful to learn a bit more about it. After all, while MAKO's currently chunky revenue is largely affected by sales of its high-priced RIO systems, the company's bread and butter going forward will be the recurring revenue stream which results from the sales of its instruments and implants.

Sure enough, MAKO CEO Maurice Ferre had this to say during the company's most recent conference call:

...Hip is going to have a major contribution to our growth. And it's a very important piece of it, it's still early on. We love what we're seeing with our partners, Pipeline, and the type of feedback that we're getting on the PST Cup in particular. This is a very unique technology in terms of combining this porous structured technology and allows for rapid bone absorption. So we're using very novel and unique implants that I think in their own rights are best-in-class.

So what makes these implants so unique? As Dr. Ferre alluded and according to MAKO's THA literature, the porous structured technology in these titanium implants is "highly frictional and offers outer struts designed to interlock with bone." 


Source: MAKO Surgical Hip 2.0 brochure.

Highly frictional, indeed. In fact, those implants look more like sandpaper than anything else. The end result, apparently, is a more stable, precisely fitting implant.

Innovative, 3-D printed implants
That, however, isn't even the coolest part. Remember the above-mentioned implant specialist Pipeline Orthopedics? Yep, the same partner in which MAKO made a $7 million investment during the third quarter of 2012. 

According to a January press release from Intelligent Manufacturing Systems, Pipeline's Senior VP of R&D Robert Cohem was a presenter at a recent Penn State event, which was supported by the National Additive Manufacturing Innovation Institute, or NAMII for short.

What, you ask, was he presenting? A "state of the art hip replacement using additive manufacturing to create a bonelike structure to vastly improve the attachment of bone to titanium to the point of being stronger than bone at the attachment point, [greatly reducing] time to full recovery." Sounds an awful lot like the implants MAKO is using in its THA solution, right?

Sure enough, according to a presentation last year from additive manufacturing specialist EOS, Pipeline Orthopedics was all set in early 2012 to market titanium implants, which were created using EOS' specialized direct metal laser-sintering 3-D printing technology. For those of you keeping track, this is the same EOS which, until 2004, had outstanding patent infringement lawsuits against 3D Systems (NYSE:DDD), which it only agreed to drop after 3D Systems agreed to acquire its "Stereos" rapid prototyping technology.

Interestingly enough, this also serves as a fantastic reminder that highly visible publicly traded companies like 3D Systems aren't the only games in town for additive manufacturing. Nonetheless, as I've mentioned before, because the 3-D printing industry still arguably remains in its infancy, there should be plenty of room for multiple companies in the space to thrive -- especially market leading stalwarts like 3D Systems.

Foolish final thoughts
In the end, by investing in the development of innovative implants to complement its own cutting-edge robotic surgery system, MAKO is effectively working to differentiate itself from other implant providers like Zimmer, Stryker, and health care giant Johnson & Johnson (NYSE:JNJ) -- the last of which just lost its first of 10,750 lawsuits over defective metal-on-metal hip implants.

Finally, considering MAKO is also continuing to grow the mountain of clinical evidence in support of the effectiveness of its RIO systems and MAKOplasty knee and hip procedures, it seems an increasingly safe bet that the future is bright for this young robotic surgery company.

Fool contributor Steve Symington owns shares of MAKO Surgical . The Motley Fool recommends 3D Systems, Johnson & Johnson, and MAKO Surgical . The Motley Fool owns shares of 3D Systems, Johnson & Johnson, and Zimmer Holdings and has the following options: Short Jan 2014 $36 Calls on 3D Systems and Short Jan 2014 $20 Puts on 3D Systems. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.