Biomedical Engineering Reference
In-Depth Information
Designs Without Allowance for Rollback
Do Not Allow Femoral-Tibial Shift
Tipping Moment
Tipping Moment
Excessive Posterior
Loading
Excessive Anterior
Loading
Unable to Shift
in Extension
Unable to Shift
in Flexion
Fig. 6.27
Excessive Anterior-Posterior Tipping Forces Resulting from Lack of Provision
for Roll Back
Less constrained designs such as the "Marmor" and "Gunston" designs of the
late 60's failed due to excessive contact stress and material overloading [15, 16] as
shown in Fig. 6.28.
Fig. 6.28
Worn Gunston Tibial Component
