Different Degrees Of Flexion Research Articles

In vivo changes in the neuroforaminal size at flexion-extension and axial rotation of the cervical spine in healthy persons examined using kinematic magnetic resonance imaging.

In vivo flexion-extension and axial rotation magnetic resonance imaging (MRI) studies of the cervical spine were performed inside a positioning device. To determine the functional changes of neuroforaminal size that occur during flexion-extension and axial rotation of the cervical spine in healthy persons. Kinematic MRI studies of the cervical spine were performed to obtain detailed information about the functional changes that occur in neuroforaminal size during flexion-extention and axial rotation. The results were compared with published data of in vitro functional flexion-extension and axial rotation studies of the cervical spine. Inside a positioning device, the cervical spines of 30 healthy persons were examined in a whole-body magnetic resonance scanner from 40 degrees of flexion to 30 degrees of extension at nine different angle positions. In addition, axial rotation was performed at neutral position (0 degrees ) and at 20 degrees and 40 degrees of axial rotation to both sides. The images were analyzed with respect to the neuroforaminal size at each position using a reformatted 3D-FISP sequence. At flexion, widening of the neuroforaminal size of up to 31% (compared with neutral position, 0 degrees ) was observed. Conversely, at extension a decrease in the size of the neuroforamen of up to 20% was recognized. At 20 degrees and 40 degrees of ipsilateral rotation of the head, a reduction in the neuroforaminal size of up to 15% and 23%, respectively, compared with the neutral position was noted. In contrast, a widening of the foraminal size was recognized on the contralateral side of 9% and 20% at 20 degrees and 40 degrees rotation. Statistically significant differences (p <== 0.05) were found in the neuroforaminal size between different degrees of flexion and extension and in addition for axial rotation compared to neutral position (0 degrees ). Compared with the results of previous biomechanical studies of human cadaver cervical spines, kinematic MRI provides additional noninvasive data concerning the physiological changes of the neuroforaminal size during flexion-extension and axial rotation in healthy individuals.

Biomechanical Effects of Different Surgical Procedures on the Extensor Mechanism of the Patellofemoral Joint

Loadbearing stresses in the patellofemoral joint were studied at different degrees of flexion before and after various surgical techniques recommended to treat knee disorders. Surgical procedures intended to reduce the intensity of stress were analyzed experimentally. The study was done using different experimental methods on whole knee specimens from fresh human cadavers that were not treated with formaldehyde. The results indicate that the most predictable procedure for increasing surface area and decreasing patellar stress is a combined procedure of anterior displacement of the anterior tibial tubercle by 1 cm while displacing it 0.5 to 1 cm medially.

Arthrography (Plica Views)

In 45 patients with chronic knee problems arthrograms of the knee were obtained with emphasis on plica views. Thirty arthrograms showed radiographic evidence of plica syndrome. Three patients had thin bands in the proximal part of the suprapatellar pouch. Four patients had infrapatellar plicae. Eighteen patients had suprapatellar plicae, and five had mediopatellar plicae. The cross-table lateral view of the knee in different degrees of flexion is a valuable prognostic method. Five patients with suprapatellar plicae demonstrated excursion of the thick fibrotic band over the anteromedial femoral condyle during arthrography with the knee in different degrees of flexion. These patients did not respond to conservative treatment and required surgical excision of the plicae. Cross-table anteroposterior and tangential views with the medial side of the knee facing upward demonstrate impingement of the medial femoral condyle or the medial facet joint of the patella by the fibrotic mediopatellar plica. All patients (5 of 5) with mediopatellar plicae required surgical excision of the plicae.

An experimental analysis of injuries to the menisci of the knee joint

Direct methods were used to determine the distribution of injuries to the menisci in formalin fixed knee joints, rotated under physiological pressures when extended and at different degrees of flexion. The position of the joint during rotation rather than the direction of rotation determined the distribution of injury between the menisci, whereas both direction of rotation and joint position determined the position of major types of lesion within the meniscus. Support is given for the view that the incidence of injury to the lateral meniscus is higher than generally accepted.