
Andrew Usner, a military veteran and nursing student at Colorado State University Pueblo, experienced knee pain that significantly impacted his daily life.
He previously served in the Army Reserves as a mechanic for five years, moved to Fort Carson and was deployed to Afghanistan in 2016. Following his discharge, Usner and his wife, Charissa, stayed in Colorado, where he worked at the Pueblo Chemical Depot and the federal prison complex. He used the GI Bill to pursue a degree in nursing at Colorado State University Pueblo.
Years of weightlifting and physical demands from military service contributed to his deteriorating condition. Then during a seemingly innocuous light jog, his pain became particularly noticeable.
The knee pain caused Usner to lose the ability to lift between 100 to 200 pounds during his usual weightlifting squat exercise in the gym. “I knew that something was wrong. I went to multiple doctors, and they were pretty much like, ‘You’re fine, let’s put a brace on it, you know. Don’t worry about it.’”
Despite multiple medical consultations, including physical therapy, his condition did not improve. Eventually, an MRI revealed severe focal cartilage loss, leading him to meet Dr. Benjamin Kam to discuss treatment options, including the MACI (Matrix-Induced Autologous Chondrocyte Implantation) procedure.
“When I saw Andrew’s MRI results, it was clear that he was dealing with a significant focal cartilage defect,” Dr. Kam said. “Given his age, activity level, and overall health, he was an ideal candidate for MACI.”

Usner agreed to surgery, understanding it could provide long-term relief and reduce the likelihood of additional surgeries in the future. The catch: not everyone is an ideal candidate for a MACI procedure, and it requires more than one surgery. The first surgery determines whether the damage can be fixed in this way, with a follow-on surgery to complete the cartilage implantation.

“Dr. Kam really walked me through the process,” Usner said. “I trusted his recommendation, and it made sense for my situation. As a nurse, I’ll be on my feet all day long. I wanted a solution that keeps me mobile and without pain for as long as possible.”
The MACI procedure: First of its kind in Pueblo
Dr. Kam explained that the MACI procedure involves harvesting cartilage cells from the patient’s body and cultivating them in a laboratory. These cells are later re-implanted into the damaged area to encourage cartilage regeneration.
“We’re essentially using the patient’s own cells to repair the damage,” Dr. Kam said. “This is one of only a few techniques proven to regrow your body’s own cartilage back into your knee joint —robust enough that you can eventually return to sporting activity.”
The first stage of the procedure involves arthroscopic surgery to extract a small piece of cartilage, which is sent to a specialized lab for culturing. After several weeks of growth, the cultivated cells are embedded onto a collagen membrane and prepared for the second surgery. In the second stage, the prepared matrix is implanted into the affected area, where it integrates with surrounding tissue.
Usner’s first surgery occurred in October 2024 with the second surgery occurring in December 2024. Both procedures were conducted at UCHealth Parkview Pueblo West hospital.
“Andrew’s commitment to following all post-surgical protocols was also critical,” Dr. Kam emphasized. “The success of MACI relies heavily on the patient’s rehabilitation efforts.”
Staying motivated through rehabilitation and recovery after MACI
The recovery process after MACI involves gradual rehabilitation to ensure the implanted cartilage integrates properly. Following surgery, Usner used a continuous passive motion (CPM) machine to gently move his knee, maintaining mobility and promoting cell growth.
“It was tough at first,” Usner said. “The CPM machine kept my knee moving, but it was a constant reminder to be patient with the process.”
Weight-bearing restrictions and structured physical therapy were also part of the recovery plan.
“The key is controlled movement,” Dr. Kam said. “We want the new cartilage cells to adapt to their environment without being overloaded too quickly.”

Usner credits his wife’s unwavering support as crucial to the first stages of the recovery process.
“My wife, Charissa, has been great dealing with essentially two kids at this point — taking care of me and my 2-year-old son, Sidney,” Usner joked. “She’s been very kind and supportive and instrumental in helping me stay on track. She’s starting to let me test my limits a little bit.”
Throughout his recovery, Usner looks toward achieving significant milestones, including regaining increased range of motion and progressing to partial weight-bearing. By the spring semester, he anticipates walking unaided.
“Seeing progress, even small wins like bending my knee further, keeps me motivated,” Usner remarked.
Full recovery is expected to take up to a year, with gradual improvements over time. Usner’s focus remains on returning to activities like weightlifting and enjoying outdoor time with his family.
Looking ahead and optimistic for a future free of knee pain
The MACI procedure has already alleviated some of Usner’s pain, and he sees improvement to his knee function. These improvements have enabled him to concentrate on his nursing studies and prepare for a physically demanding career.
“I’m grateful for the care I received,” Usner said. “As the cartilage heals and I get stronger, I expect to see a significant difference in my quality of life.”
Dr. Kam highlighted the broader implications of Usner’s success. “Stories like Andrew’s show what is possible with advancements in orthopedic surgery. It’s rewarding to see patients regain their mobility and return to the activities they enjoy.”
A national survey highlighted the significant impact of knee pain on patients’ lives. The survey revealed that nearly three in five (57%) patients have experienced knee pain for more than five years, and almost one-third (32%) have had knee pain for more than 10 years. Long-term arthritic pain can have widespread consequences on patients’ mental health and social life.
Dr. Kam and the UCHealth Parkview Pueblo West team provided comprehensive care throughout the process.
“From the hospital staff, nurses, offsite lab technicians growing the cartilage cells to our local physical therapists guiding rehabilitation, every step along the path matters,” Dr. Kam said.
Physical therapists and support staff will work closely with Usner to monitor his progress and adjust his rehabilitation program as needed. UCHealth’s Parkview facilities and resources ensure a seamless experience from initial consultation to recovery.
Usner’s experience highlights the potential benefits of MACI for patients with similar conditions.
“Procedures like MACI can provide meaningful solutions for those dealing with cartilage damage,” Dr. Kam added. “It’s important to seek expert guidance and consider all available options.”
Usner’s journey through the MACI procedure demonstrates the effectiveness of new, modern cartilage repair techniques. With careful planning, dedicated support, and a commitment to recovery, Usner has taken significant steps toward regaining his mobility and achieving his personal and professional goals.
To learn more about MACI or schedule a consultation, visit UCHealth Orthopedics or call their office at 719-595-7780.