Suprapatellar versus Infra-Patellar Intramedullary Nail Insertion of the Tibia: A Cadaveric Model for Comparison of Patellofemoral Contact Pressures and Forces

It is known that structural integrity of articular cartilage is compromised at impact loads exceeding 25 MPa, and chondrocyte apoptosis can occur at sustained loads of as little as 4.5 MPa in immature bovine cartilage. The results of this study indicate that although the patellofemoral contact pressures are higher with SP nail insertion, they remain below the values reported to be detrimental to articular cartilage. Based on these data, we do not believe that the SP entry portal poses a significant risk to the viability or structural integrity of the articular cartilage of the patellofemoral joint. Clinical correlation is needed.