SBIR Phase I: A Compliant Intramedullary Stem to Increase Longevity of Total Knee Replacements

The broader impact/commercial potential of this Small Business Innovation Research (SBIR) Phase I project is a novel ancillary orthopedic implant for increasing the lifespan of total knee replacement devices, with a tibial stem which bends and flexes to accommodate knee motion and relieve mechanical stress. Knee replacement is a common procedure for osteoarthritis with one million patients undergoing knee replacement in the United States each year. These systems have a failure rate of 10-20% within 20 years due to mechanical wear and fatigue. Failures often require subsequent invasive surgical revisions with decreased success, and increased risks of knee fusion or above-knee amputation. Each revision also results in approximately $30,000 of additional costs and resources needed for the surgical revision and follow on care. The purpose of this project is to develop a novel ancillary implanted device that reduces the mechanical stress and strain of total knee replacement orthopeduc implants, extending their functional lifespans. This Small Business Innovation Research (SBIR) Phase I project will prototype and validate a flexible tibial stem providing mechanical relief for orthopedic knee replacement implants. The device integrates a compliant mechanical mechanism accommodating the multi-dimensional knee motion to reduce wear on the primary implant while avoiding additional wear surfaces. During this Phase 1 project, the design engineering of system will be finalized, full implant prototypes fabricated, and the prototypes validated in an accelerated mechanical testing model. The specific technical objectives are to optimize structural features for overload protection of the stem, validate short-term implant performance in overload scenarios and failure, and cycle test prototype stems under accelerated mechanical testing to validate long-term survivorship under simulated patient conditions including walking and general movement under daily use. The results are expected to demonstrate feasibility for the design and contraints for developing a device suitable for eventual human use at a future date. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.