Patellofemoral kinematics during different loaded dynamic activities: an in vivo pilot study

Abstract Optical motion capture (OMC) is the current gold standard for motion analysis, however measuring patellofemoral kinematics is not possible using the technique. One approach to measuring in-vivo kinematics is to use biplane video X-ray (BVX) and 3D models generated from MRI to track the movement of the patellar. Understanding how the patellar is moving during different loaded dynamic activities can help with understanding the effects of different interventions when treating disease or injury. Objective To develop a protocol and compare patellofemoral kinematics for different activities using biplane video X-ray (BVX) Methods Two healthy volunteers performed level walk, lunge, and stair ascent activities while simultaneous capturing BVX and synchronised OMC. Participants undertook MR imaging (Magnetom 3T Prisma, Siemens) which was manually segmented into 3D bone models (Simpleware Scan IP, Synopsis). Bone position and orientation for the patellar and femur were calculated by manual matching of 3D Bone models to X-Rays (DSX Suite, C-Motion, Inc.). Patellofemoral kinematics were calculated using Visual 3D (C-Motion, Inc.). Results Initial results show that patellar flexion(+) (PF) was greatest during lunge (52.1º) compared with stair ascent (49.4º) and stance phase of gait (5.4º), however stair ascent had the largest PF range of motion (ROM) of 48.8º. The lunge activity had the greatest ROM for patellar lateral rotation (12.8º) compared with stair ascent (8.7º) and gait (3.7º). Patellar lateral (+) tilt was found to be greatest during gait (8.4º) compared with stair ascent (6.7º) and lunge (6.8º). Conclusions These results highlight the variability of patellofemoral kinematics between different loaded dynamic activities. When considering the influence and efficacy of patellofemoral interventions it is important to investigate different activities to fully understand their effects. Future work will look at more dynamic activities and to investigate further the effect of different activities on patellofemoral tracking. Declaration of Interest (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project