Innovative tissue transplant surgery helps soccer player return to form

Alex Penswater has been playing soccer since he could walk. Now a senior at Jackson Memorial High School, the 17-year-old left midfielder is no stranger to the aches and pains that come with a lifelong dedication to athletics. However, when he experienced severe pain in his right shin, he couldn’t ignore the discomfort.

“We looked for the closest sports medicine provider, which, thankfully, was Dr. Greller,” says Alex’s mother, Sandy.

Atlantic Health orthopedic surgeon and sports medicine specialist Michael Greller, MD, ordered X-rays of Alex’s leg, which revealed a fibula fracture that was in the process of healing. But it was the image of Alex’s knee that caught Dr. Greller’s attention.

After further imaging tests, Alex was diagnosed with osteochondritis dissecans (OCD), a condition in which the bone beneath the cartilage in a joint softens, weakens and eventually dies due to lack of blood flow.

Repairing the joint by replacing diseased tissue

“When you have a cartilage injury like this, you have to see if it involves just the cartilage layer, which is the lining of the knee joint, or if it also involves bone,” Dr. Greller explains. “Since Alex’s injury involved bone, we had to replace both.”

There are several options for treating OCD. Because the lesion in Alex’s knee was quite large, Dr. Greller chose allograft transplant surgery, which replaces the diseased bone and cartilage with fresh tissue from a deceased donor — similar to an organ transplant.

“Every cartilage lesion has its own personality,” Dr. Greller explains. “The surgeon and the patient are a team. We consider each patient’s activity level, type of injury, joint health and willingness to commit to an extensive rehabilitation process to determine the appropriate surgical approach.”

A donor match was identified using MRI and CT scans of Alex’s knee. During surgery, Dr. Greller shaped a “plug” of the donor bone to match Alex’s knee exactly. The plug was then inserted into the space after damaged bone and cartilage were removed from the knee. Alex’s healthy bone will grow into the donor bone, repairing and strengthening the knee joint.

After surgery, Alex used crutches for six weeks and underwent six months of physical therapy. He could not play soccer during this time to ensure that the bones and cartilage healed and joined properly. Because he had suffered fractures to the fibula, foot and hip — all on his right side within one year — Dr. Greller referred him to a metabolic medicine physician who specializes in diseases of the bone. Alex is also working with a sports medicine specialist to improve his body mechanics to prevent future injuries.

“Dr. Greller and his staff are wonderful,” says Sandy. “They walked us through everything step by step and even worked with our insurance company to ensure the surgery was covered.”

Now back to delivering pizzas after school and improving his golf game, Alex was recently cleared by Dr. Greller to resume playing soccer, too.

“Alex is an outstanding kid,” Dr. Greller says. “He was motivated to respect the healing and rehab process to get back to what he loves to do.”

“My knee feels great,” Alex says. “I don’t have any pain. I’m ready to get back on the field.”

Learn About Sports Medicine

Published: June 03, 2026

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