Matthew Teeter carefully rotates a cementless tibial baseplate in his hands, its surface etched with faint lines and discolorations that tell a story years in the making—242 stories, to be exact. In London, Ontario, at the Implant Retrieval Laboratory housed within the London Health Sciences Centre Research Institute (LHSCRI), Teeter and his team have been decoding the hidden life of hip and knee implants, examining more than 240 retrieved components to understand how these medical marvels degrade over time. While most patients experience decades of pain-free mobility, the reality inside the body is far from static. Every step, every movement, sets off a microscopic chain reaction of wear and chemical change that can, over time, compromise even the most advanced devices.
The study, published in npj Materials Degradation, reveals that the dominant degradation process in both hip and knee implants is tribocorrosion—mechanically assisted corrosion where motion and biology conspire to accelerate damage. Using optical and scanning electron microscopy alongside spectroscopy, researchers assigned damage scores and mapped corrosion patterns across the retrieved implants. What they found was not just wear, but a dynamic, repeating cycle: the protective oxide layer on titanium implants is stripped away in milliseconds with each movement, exposing the metal to body fluids. The body responds chemically, reforming the oxide layer—only for it to be worn away again. This constant breaking and rebuilding creates a surface in perpetual crisis.
Certain patient factors significantly influence this process. Infection before or during surgery was linked to higher damage scores at the trunnion—the critical junction in hip implants where the stem meets the ball. Meanwhile, patients with inflammatory arthritis or those with cemented hip implants showed lower levels of damage, suggesting that biological and design factors can either accelerate or mitigate degradation. Yolanda Hedberg, a chemistry professor at Western University, emphasizes that even asymptomatic patients undergo continuous chemical changes around their implants. "Having an implant in your body is going to change your body chemistry," she says. "You might not feel it, but it’s happening."
Teeter, who also directs Western’s Bone and Joint Institute, sees this research as a bridge between engineering and medicine. By analyzing real-world implant failures, his team provides manufacturers with data to refine materials and design, and surgeons with insights to make more personalized decisions. The lab’s collection—the largest in Canada of failed orthopedic implants—offers an unprecedented window into long-term performance.
As implant technology advances, so must our understanding of its interaction with the human body. This research doesn’t undermine the success of joint replacements—it enhances it. By illuminating the invisible processes within, it paves the way for longer-lasting, more resilient implants, ensuring that the second chance mobility provides can truly last a lifetime.