Gait analysis and muscle weight analysis after lower extremity fractures in a small animal model

Background: Besides adequate healing of bone and soft tissues, mobility represents a significant factor in functional outcome after lower extremity fractures. Although gait analysis is gaining clinical interest and importance in the rehabilitation of patients with fractures, it is rarely used in experimental fracture healing research. The aim of this study is to establish an accurate gait analysis method for fracture healing research in small animal models and to evaluate the influence of a lower extremity fracture on gait pattern and muscle atrophy in rats.Research question: How does an intramedullary stabilized femur fracture influence the gait pattern and muscle atrophy during fracture healing in rats?Methods: An isolated femur fracture with intramedullary stabilization was induced in 26 Sprague Dawley rats. Different gait parameters (e.g. intensity, print area, stand duration, duty cycle, and swing speed) were evaluated with the CatWalk gait analysis system during the fracture healing process. Furthermore, muscle weight analysis was performed at different time points.Results: The gait analyses with the CatWalk system showed a high correlation with the osteogenesis of fracture healing in this model. Muscle atrophy increased during the early fracture healing stages and then decreased in the later stages.Significance: We are the first to show that the CatWalk system is a useful tool to perform gait analyses after lower extremity fractures in a murine model. These results could form a basis for future gait analyses research in fracture healing studies to improve knowledge about bone regeneration and rehabilitation after lower extremity fractures.