Preschool teacher gets a new knee, a new hip—and a pain-free path forward

Christy Hofmanner could no longer ignore that she was having a difficult time lowering herself to the floor and standing back up. As a preschool teacher at a Montessori school, this was a problem.

Gradually, the pain in her knees began to affect other aspects of her life. She lived just outside West Chester Borough and enjoyed walking through town. But more and more, it took everything she had just to walk from her car into her home at the end of the day.

At her wit’s end, Hofmanner scheduled an appointment with Andrew B. Old, MD, an orthopaedic surgeon at Penn Medicine Chester County Hospital. X-rays showed she had advanced osteoarthritis. The cartilage in both of her knees had worn away, leaving bone rubbing against bone. The deterioration was slightly less severe in her left knee.

Hofmanner was 47 at the time. Her mother had also needed a knee replacement—but in her 60s. Old explained that osteoarthritis, while more common in older adults, wasn’t unusual in people under 50. It could be triggered by a serious injury or by professions, like Hofmanner's, that put a lot of wear and tear on the joints.

Old prescribed two months of physical therapy, but Hofmanner’s pain persisted. Next came steroid injections in each knee, which worked very well. For eight months, she felt like a new woman. But the next round of injections only held the pain at bay for two months.

At that point, Old shifted course. He injected Hofmanner’s knees with Euflexxa, a treatment that replenishes some of the joint’s lost hyaluronic acid, helping with lubrication and shock absorption. The first round gave her six pain-free months. The second round had no effect at all.

Increasingly, Hofmanner—an avid traveler—felt limited by her physical condition. On good days, she could live life normally. On bad days, she could barely make it around her three-story townhouse.

From their first meeting, Hofmanner appreciated Old’s straightforward approach. After exhausting all available “conservative measures,” he told her it was time to consider replacing her more problematic right knee. With several trips on the horizon, she agreed.

Progress impeded

Old replaced Hofmanner’s right knee at Chester County Hospital on June 5, 2023. He performed the surgery with assistance from the state-of-the-art Zimmer Biomet Rosa Knee System. He estimated that at least 75 percent of his knee replacements that year were robotic-assisted.

According to Old, the primary advantage of robot-assisted knee replacement is precision. Traditionally, knee surgery had been done—at least in part—by feel.

“When we do the knee replacement without the robot, we're making some assumptions for each patient, within a set of parameters,” he said. “With the robot, I can customize the surgery to the patient's anatomy. The key to knee replacement surgery is balancing the ligaments, and the robot can help me with that. It also allows me to rotate the implant based on the objective data it’s providing.”

Old added that although published studies hadn’t yet quantified differences in patient experience or recovery between robotic and conventional surgery, he believed the metrics simply hadn’t caught up to the technology.

“I’m not doing as much soft tissue dissection or ligament releases with the robot as I do manually because the robot tells me how much I need to free up,” he said. “And so, I'm hopeful that might be providing patients with a little less pain and a little faster recovery.”

Hofmanner was walking just four hours after her surgery. After completing a series of mobility challenges the next morning, she was discharged.

“It was a very different process from what my mom went through,” she said. “She was in the hospital for two or three days after her surgery, and she was much more stationary.”

Hofmanner admitted that the first couple of weeks were tough. But she approached recovery like a marathon. Old had told her to expect to feel back to normal within eight to ten months. She dutifully attended physical therapy sessions at Premier Orthopedics throughout the summer.

By October, Hofmanner's range of motion had returned to normal, but she still experienced pain in her right leg. At her physical therapist’s recommendation, she scheduled another appointment with Old.

An X-ray revealed that her right hip was in even worse shape than her knee had been. Though it had been less than five months since her last surgery, Old recommended replacing the hip as well.

“I had a big summer coming up,” she said. “My son was graduating from high school, and I was taking my mom to Venice. The thinking was, the longer we waited, the more this was going to interfere with all of that.”

So, the day after her class’s holiday party in December, Hofmanner underwent her second major surgery.

Hofmanner might have been trying to put a positive spin on her situation, but she insisted the second surgery was easier than the first.

“Three days after my hip surgery, I didn’t need a walker,” she said. “And I was like, ‘Wait, this is it?’ There wasn’t much swelling or pain. Even the physical therapy exercises, by comparison, were ridiculously easy.”

It wasn’t just her perception, said Old, who doesn’t use a robot for hip replacements.

“A hip replacement is a much better-tolerated operation from a patient's standpoint,” he said. “That's actually one of the main factors that led me to robotic knee replacements.”

Satisfaction rates for hip replacement surgery, he said, averaged better than 95 percent. For knee replacement, satisfaction hovered around 85 percent.

“I see that 15 percent of people who don’t like their knee replacement as a huge opportunity for the medical field to try to play catch up,” Old said. “The hip replacement is a fantastic operation, and the knee replacement is not. That's just the reality. But many surgeons like me see this as a tremendous opportunity for change. And I believe we're closing the gap in increments.”

“Everybody’s anatomy is not the same,” he continued. “And yet, we've treated everyone with this bell-curve approach. Robotic knee replacement is changing the paradigm by enabling surgeons to tailor the surgery to the patient. It's just scratching the surface, but it's already clear this is the way forward.”

Meanwhile, Hofmanner conceded she’d likely need to have her left knee replaced too; however, Old believes that's a conversation for a few years down the road.

More immediate was her son’s graduation in June. To celebrate, she was taking him to a resort in Punta Cana, Mexico. Soon after, she would travel to Italy with her mom, a once-in-a-lifetime experience. They’d return just in time for Hofmanner to help move her son into college.

And this time, she was looking forward to doing all of it free of pain.