Validation of an Internal Measurement Unit to Measure Knee Kinematics and ACL Fatigue in Cadaveric Specimens During Simulated One-Legged Landing

Abstract

Participation in sports has been on the rise in the last few years, and while regular activity in sports has many benefits, there is always an associated risk of injury. Sport related injury can happen in any part of an athlete’s body, however the most common of these injuries occur in the lower limbs with of the most devastating injuries being damage to a ligament. Among ligament damage, a rupture in the Anterior Cruciate Ligament is most common. While there are several different mechanisms for Anterior Cruciate Ligament tears, fatigue induced non-contact injuries are the most trackable. The purpose of this research was to correlate the data obtained through a commercially available IMU to that obtained through cadaveric testing to determine whether the selected IMU is valid for field testing and tracking potential fatigue levels of the ACL. Using 10 cadaveric specimens, regression models were developed and RMSE and abs % error values were calculated in addition to BA plots being constructed between aspects of both systems. Very strong correlations were observed between linear acceleration and force, with strong correlations in nearly all others compared aspects. Additionally, nearly all constructed models produced an abs % error of less than 10%. And while we recognize there to be several limitations with our study, we ultimately conclude that APDM Opal might be viable for on-field usage. However, additional laboratory studies to account for different actions and artifact motion that may be experienced by the IMU may be required before on-field usage begins.