Experimental Stem Cell Therapy Could Treat Damaged Knee Cartilage

Skiing in Aspen, Sean Fair mistimed a landing and felt a shooting pain in his right knee as he crumpled into the snow. He had to slide down the steep slope on his left ski. The doctor revealed that Fair’s agony originated from a quarter-sized hole in the cartilage of his knee.

For an active person like Fair, traditional surgery options, like a total knee replacement, restrict motion and are less than ideal. Advances in experimental cartilage repair stem cell treatments, however, now offer new opportunities for young patients to preserve mobility, that defining value of youth.

Fair played football, among other sports, in high school. He played tennis in college and continued to play until he had his ski incident at the age of 31.

“All of a sudden, not being able to do anything, I felt 80,” he said. “All my friends would play tennis together but I would have to sit back and watch.”

Sean Fair was diagnosed with OCD, or osteochondritis dissecans. This condition typically develops in teenagers but doesn’t usually present symptoms until adulthood when the joint experiences some form of trauma. OCD lesions involve holes, cracks, or loose articular cartilage in a joint.

Fair met with Dr. Andreas Gomoll, an orthopedic surgeon at the Brigham and Women’s Hospital in Boston. They discussed knee replacement surgery, microfracture surgery and the possibility of using healthy cartilage from a cadaver donor.

Knee replacement surgery for patients as young as Fair often results with low satisfaction. People who receive the standard metal and plastic knee replacement are functionally limited and face unexpected physical challenges when it comes to activities more intense than a walk. Microfracture surgery would be better, but Fair’s injury was too large for that to be practical.  Fair and Gomoll decided to wait for a cadaver donor. While waiting, however, Fair joined a clinical trial to test a new approach that would fill the gap in his cartilage with stem cells.

Stem cells can be thought of as undecided cells. They’re mostly present in embryos and neonates, but they are also found in adults as well. Given the correct environment, and depending on the type of stem cell, they can become more specific cells, like muscle cells or cartilage-forming cells. In Fair’s case, Gomoll used donated umbilical cord stem cells from healthy babies delivered in the US. Umbilical cord stem cells are useful because they are able to morph into cartilage-forming cells, they don’t require the destruction of an embryo and they have immunosuppressive properties that wouldn’t cause Fair’s body to reject them.

The procedure looked simple. Gomoll made a vertical incision in Fair’s kneecap, cutting through the skin and the yellow fat to expose the white cartilage. Gomoll used stainless steel tools to clamp open the incision, while he used a metal ring spanner to scrape the edges of the cartilage pothole. (Picture using a spoon to carve a hole in a large eraser.) Next, the surgeon drilled seven coffee stirrer-sized holes into the bone at the bottom of the quarter-sized pothole. He injected the clear stem cell gel into each coffee stirrer-sized hole and then filled the quarter-sized hole up to its edges with the rest of the stem cell gel. Gomoll smoothed down the stem cell gel like icing on a cake. Then he sutured the wound closed.

Fair wasn’t quick to start walking right after the procedure. His knee needed to heal and then he would have to follow a strict rehabilitation process of weekly physical therapy sessions.

Months after his surgery, the stem cells in Fair’s knee developed into chondrocytes, cells that secrete a matrix of cartilage, and sealed the pothole in Fair’s knee. As of now, Fair is thankful for his treatment. His right knee has healed, but he’s still not at 100 percent.

“My other knee unfortunately, because of all the issues the [right knee] had, also needs reconstruction,” Fair said. “I’ve got to be careful when I carry my two-and-half-year–old down the steps. Functionally I can walk. I can chase him. I can outrun him, still. Other than that, it’s not a lot of peripheral movement I can do yet.”

According to Gomoll, about 15 other Americans have received the same experimental treatment as Fair. Before this therapy can be offered at any hospital in the US, the clinical trial must obtain FDA approval after proving its efficacy with a larger, more randomized sample of patients. But Gomoll doesn’t seem too worried. He says hundreds of patients in South Korea have already undergone the same procedure. Getting there will take some time and money; running comprehensive trials is expensive. Once the procedure is approved, Gomoll imagines thousands of cartilage damaged patients like Fair would potentially be treated with stem cells in the United States.