Humans are living longer than ever before. While that comes with a lot of advantages, it also means many people will eventually suffer from arthritis.
David Kulber, MD
“Our joints are made of hyaline cartilage, which is very fragile and not meant to last into a person’s 70s or 80s,” said David Kulber, MD, director of hand and upper extremity surgery at Cedars-Sinai. “It’s no surprise that as cartilage wears down, it can be painful and debilitating.”
Traditionally, the only way to reconstruct joints in upper extremities was to use artificial materials, such as silicone or pyrocarbon implants. These come with potential complications such as infection, breakage or loosening and are only a short-term solution lasting 10 years or less.
Dr. Kulber developed a novel biologic solution using homograft meniscus.
“All of these innovations are based in the idea of using the body to help heal itself. Our whole team is committed to finding tailored approaches to help our aging population stay active and pain free.”
Restoring, not distorting, normal anatomy
When it comes to reconstructive surgery, the goal has always been to restore normal anatomy rather than distort it. Previous methods of treating arthritis in the hand tended to distort anatomy, requiring the removal of bones, the insertion of artificial implants, or arthrodesis, the fusion of two bones together that would inevitably limit movement. Dr. Kulber’s research was focused on finding a more natural solution.
"I chose the meniscus because it’s made of fibrocartilage, which is hearty, strong and doesn’t deteriorate," said Dr. Kulber. "If you look at the meniscus of a person who is 90 years old and has never been injured, it will look like new. It doesn’t require a lot of blood supply or nutrients to keep it alive, and its cells are resilient to injury."
"In some ways,” Dr. Kulber adds, “meniscus is better than the hyaline cartilage we are born with."
The technique relies on the use of homograft (cadaveric) meniscus as well as stem cells within the medullary canal of the bone that serve to revascularize the tissue. Research began with basic science studies in pigs to test the efficacy of use of the meniscus to resurface joints. Within one week of implantation, the meniscus reintegrated into the tissue and within several weeks it functioned like a brand-new joint.
Dr. Kulber performed the first clinical procedure of this kind in 2014 on a finger metacarpal and has since expanded its use to other joints—finger, thumb, wrist, distal radioulnar and elbow joints. Since then, he has examined joints resurfaced via this method by using a camera inserted into the joints and found them functioning good as new.
"This revolutionizes the way we think about arthritis, because it allows us to leave everything in place and realign the bone biologically with even stronger, more resilient cartilage," said Dr. Kulber. "It’s simple and it works."
Expanding adoption and access
The success of this technique is undeniable but remains fairly unique to Cedars-Sinai due to some systematic barriers.
"I and some close peers have adopted this method of treatment and experienced great outcomes," said Dr. Kulber. "We have published three papers detailing its efficacy and look forward to teaching others how to work through it. The challenge is the availability of the homograft meniscus itself."
The meniscus must be cut and shaped in a specific manner before use, which is a difficult process that many physicians and institutions are not able to do independently. Dr. Kulber and his team are working to facilitate easier, wider access to the material and subsequently begin distributing educational content to share their knowledge with other surgeons.
"There are ways to make the procedure very easy," says Dr. Kulber. "At first it took me a couple of hours, but now it only takes about 30 minutes to replace a joint. I’ve learned a lot about how to work through the finer details to make it as simple, efficient, and effective as possible."
Innovating for the Future
The team has translated this focus on biologic solutions to solve other problems facing patients with arthritis.
"Our joints can loosen over time and, even if reconstructed, ligaments can rupture and cause arthritis as we age," says Kulber. “When ligaments are stretched or injured, they move side to side and wear away the cartilage. Even if you reline the joint with meniscus, everything else will fail if the joint is unstable."
In these cases, the team has developed methods to both reconstruct the joint itself using meniscus and regenerate the collateral ligaments. It is common to use tendons to reconstruct collateral ligaments, but even those can stretch out over time. Dr. Kulber realized that collateral ligaments in the knee have similar properties to those in our other joints and spearheaded a biomechanical study to test their use compared to the tendons traditionally used. The knee ligaments turned out to be superior based on the biomechanical stress tests.
"No one has ever done this before, and we are just beginning clinical application," says Kulber. "We’re excited about where this might lead."
Another trend becoming prevalent is thumb arthritis in young patients.
"When I first started, those getting surgery for thumb arthritis were in their 60s and 70s,” says Kulber. “Now it’s common for someone in their 30s or 40s—potentially due to repetitive use of the hands operating our phones and keyboards. The idea of doing a big operation on someone so young made us wonder how many more operations they might need over time and how we can make the process as minimally invasive as possible.”
The team turned to a nano scope—a camera so tiny it can fit into a thumb joint. Using that technology, surgeons can shave out inflammation, debride the joint and relieve a lot of the pain. Then, a small amount of liposuction is performed to extract fat with anti-inflammatory, regenerative stem cells. This is mixed with platelet-rich plasma and injected into the thumb joint. It only requires two tiny incisions and allows for quick recovery
"As part of a study, we performed this procedure on more than 30 patients and have followed them for about two years so far,” says Dr. Kulber. “Many could use their thumb within a couple weeks post-surgery, and none have needed additional procedures at this point.”
Dr. Kulber and team have now expanded indications for this procedure to include those with extensive arthritis and, after seeing great success in the thumb, are also beginning to apply it to the metacarpophalangeal joint.
"All of these innovations are based in the idea of using the body to help heal itself,” says Dr. Kulber. "Our whole team is committed to finding tailored approaches to help our aging population stay active and pain free.”