Mechanical Behavior of a Porous, Sub-total Meniscus Implant Based on Poly(trimethylene carbonate): a Pilot Study in the Knee

Meniscus tears often occur in the avascular inner part of the meniscus and therefore do not heal spontaneously. Current treatments such as meniscectomy and the implantation of allografts are insufficient. In this study we prepared a designed, sub-total, porous meniscus implant from functionalized poly(trimethylene carbonate) by stereolithography, and investigated its mechanical behavior in a human cadaveric knee. The sub-total meniscus implant was sutured to the peripheral rim of the meniscus and placed in the medial compartment of the knee. To determine the peak- and mean pressures and the contact area pressure distribution, measurements were made and compared to those of the native meniscus-, meniscectomy- and allograft implant situations. Compared to the native meniscus, meniscectomy results in considerably higher peak- and mean pressures. Compared to meniscectomy, the allograft and PTMC implants show a limited decrease in peak pressures and a much lower mean pressure. The mean pressures are close to those of the native meniscus. Both the allograft and the PTMC implant show improved mechanical behavior compared to meniscectomy. It can be expected that the mechanical function of the PTMC implant will improve upon the formation of tissue in the pores of the implant after implantation in patients.