Influence of partial meniscectomy on attachment forces, superficial strain and contact mechanics in porcine knee joints.

PURPOSE

Numerous studies investigated the reasons for premature osteoarthritis due to partial meniscectomy (PM). However, the influence of meniscectomy on attachment forces and superficial strain of the tibial meniscus is unclear. It is hypothesised that these parameters depend on the degree of PM.

METHODS

Six porcine medial menisci were placed in a custom made apparatus, and each meniscal attachment was connected to a force sensor. After printing markers onto the tibial meniscal surfaces, the menisci were positioned on a glass plate enabling optical superficial strain measurement. Additionally, contact area and pressure were investigated. Each meniscus was axially loaded up to 650 N using its respective femoral condyle. Testing was conducted intact and after 50 and 75% PM of the posterior horn and extending 75% PM to the anterior horn.

RESULTS

With increasing meniscectomy, the attachment forces decreased anteriorly by up to 17% (n.s.) and posteriorly by up to 55% (p = 0.003). The circumferential strain in the peripheral meniscal zones was not affected by the meniscectomy, while in some meniscal zones the radial strain changed from compression to tension. Contact area decreased by up to 23% (p = 0.01), resulting in an increase in 40% (p = 0.02) for the maximum contact pressure.

CONCLUSION

Partial meniscectomy significantly alters the loading situation of the meniscus and its attachments. Specifically, the attachment forces decreased with increasing amount of meniscal tissue loss, which reflects the impaired ability of the meniscus to transform axial joint load into meniscal hoop stress.