Analysis of intraoperative technique and its effect on loading patterns across the patellofemoral joint using a smart patellar implant

Abstract

To better understand the effects of total knee arthroplasty on knee biomechanics, we developed and validated a “smart” patellar implant for measuring forces in the knee. Patellar implants were created by instrumenting implants with three wireless, passive force sensors. The smart patellar implants were then used to characterize the biomechanics of the patellofemoral joint using a knee simulator and in cadavers. The effect of clinical technique on patellofemoral biomechanics was measured. This novel diagnostics tool has the potential to provide novel information on patellofemoral biomechanics and reduce post-operative complications and costs after total knee arthroplasty through objective, intraoperative feedback.

Total knee arthroplasty is a common orthopaedic procedure with approximately 700,000 new surgeries performed in the United States annually. A common complication following total knee arthroplasty is anterior knee pain, which affects tens to hundreds of thousands of people each year. The exact mechanism that leads to anterior knee pain remains unknown, but improper implant sizing may cause pathologic loading of the knee resulting in pain.