Sagittal plane articulation of the contralateral knee of subjects with posterior cruciate ligament deficiency: an observational study

Abstract

Background: The aim of the present study was to compare the in vivo articulation of the healthy knee to the contralateral knee of subjects with acute and chronic PCL injuries.

Methods: Magnetic resonance was used to generate sagittal images of 10 healthy knees and 10 knees with isolated PCL injuries (5 acute and 5 chronic). The subjects performed a supine leg press against a 150 N load. Images were generated at 15 degree intervals as the knee flexed from 0 to 90 degrees. The tibiofemoral contact (TFC), and the centre of the femoral condyle (as defined by the flexion facet centre (FFC)), were measured from the posterior tibial cortex.

Results: There was no significant difference in the TFC and FFC between the healthy knee and contralateral knee of subjects with acute and chronic PCL injuries in the medial and lateral compartments of the knee.

Conclusions: The findings of this study suggest there is no predisposing articulation abnormality to PCL injury, in the setting of chronic injury the contralateral knee does not modify its articulation profile and the contralateral knee can be used as a valid control when evaluating the articulation of the PCL deficient knee.

Figure 1

Subjects' position in the MRI scanning tunnel. The knees were positioned at 15 degree intervals between 0 and 90 degrees flexion, pressing down through the feet against a 150 N load

Figure 2

Sagittal images through the centre of the compartment of the knee were used to measure the tibiofemoral contact. The distance was measured through the posterior tibial cortex to the centre of the area of contact

Figure 3

The position of the flexion facet centre over the tibial plateau was measured in three steps: the arc and centre (FFC) of the posterior femoral condyle were defined, the tibial plateau was defined, and the distance from the perpendicular through the centre to the posterior tibial cortex was determined.

Figure 4

Graph comparing tibiofemoral contact points in the healthy and contralateral acute and chronic PCL injured knees, performing a leg press against a 150 N load through a flexion arc of 0 to 90 degrees. The pattern of tibiofemoral contact positions in healthy and contralateral acute and chronic PCL injured knees is not significantly different in both the lateral and medial compartments from 0 to 90 degrees of knee flexion

Figure 5

Graph comparing flexion facet centre positions in the healthy and contralateral acute and chronic PCL injured knees, performing a leg press against a 150 N load through a flexion arc of 0 to 90 degrees. The pattern of FFC positions in healthy and contralateral acute and chronic PCL injured knees is not significantly different in both the lateral and medial compartments from 0 to 90 degrees of knee flexion.