The influence of tibial resection on the PCL in PCL-retaining total knee arthroplasty: A clinical and cadaveric study.

BACKGROUND: The influence of tibial resection on the joint gap and on stability against posterior laxity in posterior cruciate ligament-retaining total knee arthroplasty (CR-TKA) remains unclear. In addition, there are no detailed reports regarding how much of the tibial attachment of the posterior cruciate ligament (PCL) is preserved during tibial resection. Our goals were to evaluate the influence of tibial resection on the intraoperative joint gap and on postoperative anteroposterior stability in a clinical population, and to assess the preserved area of the tibial PCL attachment using cadaveric knees. METHODS: In 20 consecutive patients, the joint gaps before and after tibial resection at 90° flexion and full extension were analyzed during CR-TKA, and anteroposterior stability was evaluated postoperatively. In 11 cadaveric knees, tibial resection with a thickness of 8, 10, 12, or 14 mm and a posterior slope of 3, 4, 5, 6, or 7° was simulated using computed tomography images, and the percentage of the preserved area of the attachment was calculated. RESULTS: The flexion gaps before and after tibial resection were 18.1 ± 1.9 mm and 18.4 ± 2.2 mm, respectively, with no statistically significant difference (p = 0.08). Similarly, the extension gap did not increase significantly before and after tibial resection (20.8 ± 2.5 mm and 21.0 ± 2.6 mm; p = 0.45). All knees maintained anteroposterior stability at the follow-up period (32.0 ± 1.9 months). The posterior slope of the tibial resection was 5.9 ± 1.4°, and the thickness of the lateral tibial resection was 10.4 ± 1.1 mm. The cutoffs to preserve more than 50% of the attachment were 10-mm thickness and 5° slope. CONCLUSIONS: Our results showed that tibial resection did not influence the intraoperative joint gap or postoperative anteroposterior stability. However, our analysis demonstrated that increased amounts of tibial resection led to considerable damage to the attachment.

Fat embolism syndrome: A severe case diagnosed early using dual-energy CT and saved with VA-ECMO and inhaled nitric oxide.

Diagnosing FES is difficult and time-consuming, and identify FES as an etiology of right ventricular volume overload for early diagnosis. Because FES is a reversible condition, even severe cases can bse treated if the patient survives the acute phase.

Pacemaker implantation for persistent sinus node dysfunction in a patient with COVID-19.

A 46-year-old woman was admitted with coronavirus disease-2019 infection. Symptomatic sinus bradycardia occurred, followed by congestive heart failure. Therapeutics such as isoproterenol, theophylline, and cilostazol could not safely improve her symptoms. She underwent pacemaker implantation 53 days after admission. Atrial pacing remained was at 60% after 6 months.

Trans-aortic pulmonary vein isolation using magnetic navigation system for paroxysmal atrial fibrillation in a patient with dextrocardia, situs inversus, and inferior vena cava continuity with azygos vein.

A 51-year-old male with dextrocardia and situs inversus underwent catheter ablation for paroxysmal atrial fibrillation. Because the procedure through the trans-septal approach was impossible due to the inferior vena cava continuity with azygos vein, we performed pulmonary vein isolation using magnetic navigation system through the retrograde trans-aortic approach. Superior and inferior left-sided and superior right-sided pulmonary veins could be isolated which was confirmed by the ablation catheter. The patient was free from atrial fibrillation episode at the 12 months follow-up except only one palpitation episode lasting nearly 12 hours at 9 months after the ablation.

Three-dimensional motion analysis of the patellar component in total knee arthroplasty by the image matching method using image correlations.

In total knee arthroplasty (TKA), the patella is significantly associated with range of motion and gait performance. Currently, no highly accurate methods are available that can measure the 3D in vivo behavior of the TKA patellar component, as the component is made of x-ray-permeable ultra-high molecular weight polyethylene. Previously, we developed a computer simulation that matches CT scan and unidirectional radiographic images using image correlations, and applied it to kinematic studies of natural and TKA knees. The examination of the measurement accuracy for the patellar bone of a fresh-frozen pig knee joint yielded a root mean square error of 0.2 mm in translation and 0.2° in rotation. In this study, we recruited four patients who had a TKA and investigated 3D movements of the patellar component during squatting. We could visualize the patellar component using the position of the holes drilled for the component peg, and estimated and visualized the contact points between the patellar and femoral components. The principles and the utility of the simulation method are reported. This analytical method is useful for evaluating the pathologies and post-surgical conditions of the knee and other joints.

A three-dimensional computed tomography study of distal femoral morphology in Japanese patients: gender differences and component fit.

BACKGROUND: Previous anthropometric studies have reported gender differences in distal femoral morphology. However, to date, very few studies have investigated the knee morphology of Japanese adults and possible gender differences. The purpose of this study was to examine the distal femoral morphology of Japanese patients, to characterize anatomical differences between male and female, and to evaluate the need to create gender-specific knee prostheses. MATERIAL AND METHODS: We evaluated 80 knees in 40 male and 40 female Japanese patients scheduled for total knee arthroplasty (TKA). The mediolateral (ML) and anteroposterior (AP) dimensions of the knees at different levels were measured preoperatively using three-dimensional computed tomography, and ML/AP aspect ratios were calculated. RESULTS: On the distal femoral cut surface, the mean ML widths were 74.9 mm for male and 65.1mm for female, and the mean AP lengths were 63.4mm for male and 58.9 mm for female. Such values were generally smaller compared to data from European and North American studies. In this study, the mean ML/AP aspect ratios were 1.31 for male and 1.25 for female, higher than those from non-Asian regions. The ML/AP ratios of Japanese patients were negatively correlated with distal femoral AP length. CONCLUSIONS: Japanese female had a relatively narrower femoral width for a given AP length than male. Our study suggests the utility of Japanese-specific implants and provides useful insights for manufacturers to design components of appropriate sizes and aspect ratios for Japanese TKA patients.