Evaluation of the Effect of Strain on ACL Graft Healing and Remodeling in a Rabbit Model


Scott A. Rodeo, MD

Project Description

Hypotheses: 1. Excessive graft strain will adversely affect healing of a tendon graft in a bone tunnel. 2. Novel MRI pulse sequences will allow detection of differences in graft collagen ultrastructure in response to varying levels of strain loading. Methods: ACL reconstruction will be performed in a rabbit model. We have verified that we can induce different levels of graft strain by varying the location of the femoral tunnel and knee flexion angle for graft fixation. We then use an external fixator on the knee to control post-operative knee motion. The independent variable (graft strain) is controlled by knee motion done using a custom-designed motion device with the animal under anesthesia. We vary the magnitude, frequency, and time of onset of strain loading. The primary outcome measure is MRI appearance of the graft (quantitative MRI- measurement of T2 relaxation time and T1 rho). Secondary outcome measures are graft healing to bone (histology) and graft attachment strength and stiffness (biomechanical testing). Role of Student: The student will participate in all aspects including animal surgery, specimen harvest, tissue dissection, biomechanical testing, data analysis, and manuscript preparation. The student will be exposed to the research environment in our laboratory, which includes senior scientists, post-doctoral fellows, technicians, and other students. They will be exposed to numerous basic laboratory techniques, and will also participate in regular laboratory meetings.

This Position Has Been Filled.