Are Korean Patients Different from Other Ethnic Groups in Total Knee Arthroplasty?

Most of the implants used for total knee arthroplasty (TKA) in Asian patients have been produced based on anthropometry of Western people. Since anatomic features and life styles are different between Western and Eastern people, there would be ethnic differences in terms of conformity of implants to the patient's anatomy or clinical results after TKA. Therefore, surgeons in Asia are particularly interested in related surgical techniques and implant designs used in TKA for improved clinical results and patient satisfaction. In this review, we investigated the anthropometric differences of Koreans from Westerners. Koreans are of shorter stature, less weight, and smaller skeletal structure and have a higher incidence of constitutional varus alignment of the lower extremity. Moreover, compared to Westerner TKA populations, the proportion of female patients was large and primary osteoarthritis was prevalent in preoperative diagnosis in Korean TKA patients. Culturally, Koreans have life styles that demand high flexion positions of the knee such as squatting, kneeling, and cross-legged sitting. Although there were no notable differences in the complication and revision rates following TKA between Westerners and Koreans, the incidence of postoperative deep vein thrombosis and pulmonary thromboembolism was lower in Koreans than Westerners. We hope that further research on implant designs and more interest in TKA will improve outcomes in Korean patients.

Effect of rotational speed of Protaper(TM) rotary file on the change of root canal configuration / 대한치과보존학회지

This study was conducted to evaluate canal configuration after shaping by ProTaper(TM) with various rotational speed in J-shaped simulated resin canals. Forty simulated root canals were divided into 4 groups, and instrumented using by ProTaper(TM) at the rotational speed of 250, 300, 350 and 400 rpm. Pre-instrumented and post-instrumented images were taken by a scanner and those were superimposed. Outer canal width, inner canal width, total canal width, and amount of transportation from original axis were measured at 1, 2, 3, 4, 5, 6, 7 and 8 mm from apex. Instrumentation time, instrument deformation and fracture were recorded. Data were analyzed by means of one-way ANOVA followed by Scheffe's test. The results were as follows 1. Regardless of rotational speed, at the 1~2 mm from the apex, axis of canal was transported to outer side of a curvature, and at 3~6 mm from the apex, to inner side of a curvature. Amounts of transportation from original axis were not significantly different among experimental groups except at 5 and 6 mm from the apex. 2. Instrumentation time of 350 and 400 rpm was significantly less than that of 250 and 300 rpm (p < 0.01). In conclusion, the rotational speed of ProTaper(TM) files in the range of 250~400 rpm does not affect the change of canal configuration, and high rotational speed reduces the instrumentation time. However, appearance of separation and distortion of Ni-Ti rotary files can occur in high rotational speed.