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

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.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.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.Cadaveric studies demonstrate that the posterior cruciate ligament (PCL) is the most important constraint to posterior translation of the tibia above 30 degrees of knee flexion[1,2]. This finding has been supported by invivo studies that have demonstrated significant posterior translation of the medial tibia in subjects with PCL injuries as the knee flexes from 0 to 90 degrees in comparison to the contralateral side[3]. However, it is debateable whether the contralateral knee can be used as a valid normal control because anatomical variations such as narrower intercondylar notch anatomy and variation in tibial slope have been identified as risk factors for cruciate ligament injury[4]. The cruciate ligaments provide important proprioceptive feedback about knee stability[5]. It has not been investigated whether the contralateral knee in a subject with a PCL injury undergoes any adaptive changes as a result of the abnormal articulation pattern in the injured knee. The aim of this study is to investigate whether the