Recently, kinematic aligned total knee arthroplasty (TKA) has gained interest for achieving better clinical outcomes over mechanical aligned TKA. The primary goal of kinematic aligned TKA is to position the femoral and tibial components so that the angles and levels of the distal and posterior femoral joint lines and the tibial joint line are each restored to the patient's natural alignment, and not to a neutral limb alignment that is unnatural for most patients. Despite good clinical outcomes reported at short to mid-term follow-up, surgeons should know reasons why this method is useful and safe surgery and carefully assess the long-term outcomes until this new technique is settled as standardized procedure for TKA. The main purpose of the present study was to compare postoperative radiography and clinical scores following kinematic and mechanical aligned TKA. Sixty TKAs—30 kinematic and 30 mechanical aligned—were performed in patients with varus-type osteoarthritis using a navigation system. Using postoperative double-leg and single-leg standing long leg radiographs, joint line orientation angle to the floor, conventional mechanical axis (cMA), and true mechanical axis (tMA; line from hip center to the lowest point of calcaneus) were compared between the two groups. One-year after surgeries, range of motion and the patient-derived score of the 2011 Knee Society Score (2011 KSS), which includes four categories: symptoms, patient satisfaction, patient expectations, and functional activities, e.g., walking/standing, standard activities, advanced activities, and discretionary activities, were compared between the two groupsPurpose
Methods
The use of cervical pedicle screws as anchors in posterior reconstruction surgery has not been widely accepted due to the neurological or vascular injury. We thus sought to investigate the accuracy of free-handed pedicle screw placement in the cervical and upper thoracic spine at the early stage of clinical application. Eight patients (five males and three females) were included in this study. Mean age was 63 years (31 to 78 years). There were three patients with rheumatoid arthritis, three with cervical fracture-dislocation, and two with spinal metastasis. Twenty-four pedicle screws (3.5 mm diameter: Vertex, Medtronic Sofamordanek) were placed into the pedicle from C2 to T2 level by free-handed technique2). Grade of breaching of pedicle cortex was divided into four groups (Grade 0–3). In addition, screw axis angle (SAA) were calculated from the horizontal and sagittal CT images and compared with pedicle transverse angle (PTA). Furthermore, perioperative complications were also examined. Our free-handed pedicle screw placement with carving technique is as follows: A longitudinal gutter was created at the lamina-lateral mass junction and then transverse gutter perpendicular to the longitudinal gutter was made at the lateral notch of lateral mass. The entry point of the pedicle screw was on the midline of lateral mass. Medial pedicle cortex through the ventral lamina was identified using the probes to create the hole within the pedicle. The hole was tapped and the screw was gently introduced into the pedicle to ensure the sagittal trajectory using fluoroscopy. In the transverse direction, 22 out of 24 screws (92%) were entirely contained within the pedicle (Grade 0). In contrast, only teo screws (8%) produced breaches less than half the screw diameter (Grade 1). In the sagittal direction, all screws were within the pedicle (Grade 0). Screw trajectories were not consistent with anatomical pedicle axis angle; the mean SAA were smaller than the mean PTA at all levels. The pedicle diameter ranged from 3.9 to 9.2 mm. The mean value gradually increased toward the caudal level. There were no neurological and vascular complications related to screw placement.
