A whole company built around one stubborn, overlooked joint - and a single titanium implant designed to fix it.
The Catamaran implant: named for its twin-keel hull, photographed here looking far calmer than the surgery it ends.
In an operating room somewhere this morning, a surgeon slides a single implant along the back of a patient's pelvis, threading an angle most of their colleagues never use. The patient has spent years being told their back hurts for reasons no scan could pin down. The implant they're getting comes from a 27-person company in Los Gatos, California, that decided to wager its entire existence on the sacroiliac joint - the small, load-bearing hinge between spine and pelvis that the rest of medicine has spent decades politely ignoring.
That company is Tenon Medical. It trades on the Nasdaq under TNON, it booked $3.9 million in revenue in 2025, and it is not, by the standards of the medical device industry, large. What it has instead is focus. Where the giants of spine sell catalogs, Tenon sells essentially one idea - the Catamaran SI Joint Fusion System - and the clinical data to back it up.
Lower-back pain is the most relatable complaint in medicine and one of the least understood. The sacroiliac joint is a prime suspect - it carries the weight of the upper body and absorbs every step - and it is estimated to be the source of pain in somewhere between 15% and 30% of chronic low-back cases. The trouble is that it hides. It does not show up neatly on imaging, it mimics disc problems, and for years patients with SI joint dysfunction got disc surgeries that fixed the wrong thing.
When surgeons did decide to fuse the joint, the standard playbook was a lateral approach: come in from the side of the pelvis and drive implants across. It works, but it is a particular geometry with particular trade-offs. Tenon's founders looked at that and asked a quieter question - not "how do we sell more lateral implants," but "is the side actually the best door into this joint?"
Tenon was incorporated in Delaware in 2012 by Richard Ferrari and Richard Ginn - a financier-operator and an inventor, which is roughly the two halves any device company needs. Ferrari, now Executive Chairman, spent his career in medical device venture and operating roles and has helped raise more than $1 billion across the companies he has touched. Ginn, the Chief Technology Officer, is a named inventor on more than 300 medical device patents. One of them grew up to be the Catamaran.
Their bet was almost contrarian in its modesty: instead of a bigger system, a smaller one. A single implant. A different trajectory - inferior-posterior, coming in from below and behind, threading dense cortical bone for a sturdier purchase. The pitch was less metal, a less invasive procedure, and a more reproducible result. Easy to say. The next decade was spent proving it.
Steven M. Foster runs the company as President & CEO, with three decades in device marketing and operations. Richard Ginn holds the CTO/COO seat. The board folds in spine luminary Stephen H. Hochschuler, M.D., and longtime device executive Robert K. Weigle, whose name sits on the company's investor correspondence.
Org-chart trivia: a company this small carries a board this deep mostly because spine surgeons trust other spine surgeons.
The Catamaran SI Joint Fusion System earned FDA clearance in 2018. Its name is not marketing whimsy alone - the implant's twin-keel geometry straddles the joint the way a catamaran's two hulls straddle the water, and the company's clinical program is named, fittingly, MAINSAIL. The system places a single implant directly across the SI joint under fluoroscopic guidance, along that inferior-posterior path, packed with autologous bone to encourage the joint to fuse into one solid unit.
One device, placed directly into the joint - fewer parts, a less invasive footprint than multi-implant lateral constructs.
A different entry trajectory through dense cortical bone, aimed at biomechanical stability and neural/vascular safety.
Image-guided placement using modified inlet, outlet and lateral views for optimized positioning.
Packed with the patient's own bone to drive radiographic fusion over time.
Tenon Medical incorporated in Delaware by Richard Ferrari and Richard Ginn.
FDA clearance for the Catamaran SI-Joint Fusion System.
Initial public offering; lists on the Nasdaq as TNON.
National commercial launch of Catamaran at the NASS meeting in Chicago.
MAINSAIL post-market study reports interim and 12-month outcomes; two peer-reviewed publications follow.
Acquires the SiVantage SImmetry / SImmetry+ portfolio - one approach becomes three.
Reports full-year 2025 revenue of $3.9M (+20%) and Q1 2026 revenue up ~90% YoY.
A clever trajectory is a hypothesis until patients report back. The MAINSAIL study - an IRB-approved, prospective, multi-center, post-market investigation - is Tenon's attempt to turn its design argument into evidence. The early readouts are the kind a small company likes to put on a slide.
Clinical sites reported no serious adverse events in the interim cohort, high satisfaction, and procedures that often wrapped in under three-quarters of an hour. On the business side, the story rhymes: full-year 2025 revenue rose 20% to $3.9 million, gross profit climbed 38% to a record $2.4 million, the fourth quarter nearly doubled, and the first quarter of 2026 came in roughly 90% ahead of the prior year. Small numbers, steep slope.
Tenon's stated mission is plain to the point of being unfashionable: "optimize SI joint surgical solutions." No talk of disruption, no manifesto. In August 2025 it backed the words with capital, acquiring the SiVantage SImmetry and SImmetry+ technologies. That move added a lateral approach to Tenon's inferior-posterior one - which is a quietly interesting admission. The company that built its identity on a different door into the joint decided the smarter long game was to hold the keys to several doors.
The same year, Tenon moved to run more of its own commercial infrastructure rather than lean on a national distributor, trading the comfort of outsourced sales for control over its growth. For a company of its size, that is a meaningful, slightly nervy choice.
Return to that surgeon and that patient. The implant goes in, the angle holds, and over the following months the joint fuses into a single quiet unit. The patient stops cataloguing their pain by the hour. Multiply that by a market where a large slice of chronic back pain traces to a joint medicine spent years failing to name, and the size of the opportunity - and the obligation - comes into focus.
Tenon Medical is still small, still proving itself, still a long way from the spine industry's heavyweights. But it has done the hard, unglamorous part: pick a real problem, design for it, and put numbers behind the design. The sacroiliac joint used to be the thing nobody could find. A company in Los Gatos decided to make it the only thing worth looking for.