Force measurement across the patellofemoral joint using a smart patellar implant following a total knee arthroplasty

Osteoarthritis is one of the leading causes of chronic pain and disability in the United States. The gold standard to treat osteoarthritis of the knee is to perform a total knee replacement. Post-operatively, as high as 21% of total knee replacement patients experience moderate to severe anterior knee pain. The exact mechanism(s) of anterior knee pain remains unknown. Patellofemoral contact forces are believed to play a significant role in the mechanism of anterior knee pain. Yet, measuring contact forces in the patella has remained a challenge. We have developed a “smart patella” to measure force magnitudes and distributions across the patellofemoral joint. We have designed and conducted proof-of-concept experiments demonstrating that our novel force sensing system has the potential to be implanted into the patellofemoral joint space with minimal alterations to modern implant design. Once implanted, our sensors measure in real time, in vivo patellofemoral contact forces.