Finite element study of a partial meniscectomy of a complete discoid lateral meniscus in adults

Incidence of osteoarthritis and genu valgus is higher after partial meniscectomy of the discoid lateral meniscus. We aimed to provide a biomechanical reference for slowing the development of osteoarthritis and genu valgus after complete discoid lateral meniscus (CDLM) surgery.

Computed tomography and magnetic resonance images of the knee were used to establish a finite element model of the knee. The discoid lateral meniscus model was cut at 2-mm intervals to obtain 10 lateral meniscus models of different widths (2-20 mm). The instantaneous stress peak and knee valgus angle were obtained by finite element analysis under the same coaxial load.

When the residual width of the lateral meniscus was greater than 12 mm, the peak stress of the knee joint and angle of genu valgus did not significantly change from preoperative levels. The contact stress peak increased slightly as the width decreased from 12 to 8 mm. When the width was reduced from 8 to 0 mm, the contact stress peak increased significantly.

For partial meniscectomy in CDLM patients, meniscus width of 8-10 mm provides a better biomechanical environment. This may reduce risk of early knee degeneration and valgus from excessive meniscectomy in conventional surgery.