Meniscal Replacement With a Silk Fibroin Scaffold Reduces Contact Stresses in the Human Knee

The aim of the current study was to verify if a previously developed silk fibroin scaffold for meniscal replacement is able to restore the physiological distribution of contact pressure (CP) over the articulating surfaces in the human knee joint, thereby reducing peak loads occurring after partial meniscectomy. The pressure distribution on the medial tibial articular surface of seven human cadaveric knee joints was analysed under continuous flexion–extension movements and under physiological loads up to 2,500 N at different flexion angles. Contact area (CA), maximum tibiofemoral CP, maximum pressure under the meniscus and the pressure distribution were analysed for the intact meniscus, after partial meniscectomy as well as after partial medial meniscal replacement using the silk fibroin scaffold. Implantation of the silk fibroin scaffold considerably improved tibiofemoral contact mechanics after partial medial meniscectomy. While the reduced CA after meniscectomy was not fully restored by the silk fibroin scaffold, clinically relevant peak pressures on the articular cartilage surface occurring after partial meniscectomy were significantly reduced. Nevertheless, at high flexion angles static testing demonstrated that normal pressure distribution comparable to the intact meniscus could not be fully achieved. The current study demonstrates that the silk fibroin implant possesses attributes that significantly improve tibiofemoral CPs within the knee joint following partial meniscectomy. However, the failure to fully recapitulate the CAs and pressures observed in the intact meniscus, particularly at high flexion angles, indicates that the implant's biomechanical properties may require further improvement to completely restore tibiofemoral contact mechanics. © 2019 The Authors. Journal of Orthopaedic Research^® published by Wiley Periodicals, Inc. on behalf of Orthopaedic Research Society. J Orthop Res 37:2583–2592, 2019