Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

OBJECTIVE: To develop a method of measuring the magnitude, direction and point of application of the patellofemoral force (PFF), directly and non-invasively in three dimensions. DESIGN AND METHODS: The compressive PFF is replaced exactly with a tensile force applied to the front of the patella. The magnitude, direction and point of application of the tensile force are then measured. The technique was applied to six normal knees mounted in a 6 degree of freedom rig with quadriceps tendon tension force (QTF) applied to balance a flexing load and to simulate weight bearing. RESULTS: The PFF was greater than in previous more invasive in vitro studies but the results correlated well with recent theoretical analyses. At 20 degrees knee flexion the force was 75% of QTF. It increased to 100% of QTF at 60 degrees knee flexion and remained at this level at higher angles of flexion. The lateral vector of the PFF was small compared to the sagittal plane vector and became negligible beyond 60 degrees of knee flexion. The point of application of the PFF to the patella moved proximally and medially with knee flexion. CONCLUSIONS: A new and reliable method of measuring PFF non-invasively and in three dimensions has been developed. RELEVANCE: A new technique is described for measuring the PFF in vitro. The non-invasive nature of the technique makes it useful for studying the effect on the PFF of simulated pathological conditions, surgical procedures and different types of knee replacement.

Type

Journal article

Journal

Clin biomech (bristol, avon)

Publication Date

01/1997

Volume

12

Pages

1 - 7