The posterior drawer is a commonly used test to diagnose an isolated PCL injury and combined PCL and PLC injury. Our aim was to analyse the effect of tibial internal and external rotation during the posterior drawer in isolated PCL and combined PCL and PLC deficient cadaver knee. Ten fresh frozen and overnight-thawed cadaver knees with an average age of 76 years and without any signs of previous knee injury were used. A custom made wooden rig with electromagnetic tracking system was used to measure the knee kinematics. Each knee was tested with posterior and anterior drawer forces of 80N and posterior drawer with simultaneous external or internal rotational torque of 5Nm. Each knee was tested in intact condition, after PCL resection and after PLC (lateral collateral ligament and popliteus tendon) resection. Intact condition of each knees served as its own control. One-tailed paired student's t test with Bonferroni correction was used. The posterior tibial displacement in a PCL deficient knee when a simultaneous external rotation torque was applied during posterior drawer at 90° flexion was not significantly different from the posterior tibial displacement with 80N posterior drawer in intact knee (p=0.22). In a PCL deficient knee posterior tibial displacement with simultaneous internal rotation torque and posterior drawer at 90° flexion was not significantly different from tibial displacement with isolated posterior drawer. In PCL and PLC deficient knee at extension with simultaneous internal rotational torque and posterior drawer force the posterior tibial displacement was not significantly different from an isolated PCL deficient condition (p=0.54). We conclude that posterior drawer in an isolated PCL deficient knee could result in negative test if tibia is held in external rotation. During a recurvatum test for PCL and PLC deficient knee, tibial internal rotation in extension results in reduced posterior laxity.
The hip joints are commonly affected in Juvenile Idiopathic Arthritis (JIA) in childhood. Common features are pain, subluxation, femoral anteversion, coxa valga, significant fixed flexion deformity and a true arthritis, with loss of articular cartilage principally from the femoral head but also the acetabulum. In children with JIA, it is accepted that a medial soft tissue release of the hips, dividing adductor longus, adductor brevis and the ilio-psoas, is a useful tool in the management of significant hip joint involvement. The principal indication for surgery is the relief of pain, but other benefits are correction of fixed flexion deformity, restoration of articular cartilage, increased abduction of the hips and, in those children who are unable to walk, frequently a transition to the potential to walk. The procedure is nearly always performed bilaterally. Our study aimed to document the restoration of articular cartilage at the hips following soft tissue release. It has been noted in the literature that there is regrowth of articular cartilage in the hip but there has been no true documentation of this and x-ray studies are unreliable as the elimination of fixed flexion deformity can prejudice accurate analysis of femoral head geometry on 2 –dimensional views. We therefore carried out MRI scanning of the hips, immediately prior to the soft tissue release and 12–18 months post-operatively. In 10 consecutive patients analysed, scans demonstrated true articular cartilage regrowth in 8 cases. We thus conclude that soft tissue release of the hips in JIA is a useful management tool, and may to some extent reverse the severe articular cartilage loss seen in these children. The next stage of our study is to analyse the articular cartilage at the time of subsequent hip arthroplasty to determine whether true hyaline cartilage is reformed or whether the reconstitute represents fibrocartilage.
