Methods

Twenty patients (17 Females and 3 Males; mean 76 years old) with bilateral symptomatic knee osteoarthritis participated. They had radiographic bilateral OA of at least grade 3 severities according to the Kellgren-Lawrence scale. All the subjects underwent unilateral TKA using Balanced Knee System®, posterior stabilized design (Ortho Development, Draper, UT). All the subjects provided informed consent. All methods and procedures were approved by our institution's ethics committee. They were asked to step on the two scales and perform relaxed standing for five seconds, placing each foot on each scale independentlys. Thereafter, anteroposterior radiographs of the whole spine and bilateral long legs were taken with use of a vertical 35.4 × 101.7-cm film.

The shoulder tilting angle was defined by the height difference between the centers of the right and left acromioclavicular joints, and the pelvic tilting angle was defined by the height difference between the centers of the right and left femoral heads. To evaluate trunk bending, the shoulder-pelvis bending angle was defined as the angle between the shoulder girdle line (Fig. 1, Line a) and the pelvic line (Fig. 1, Line b). Femorotibial angle (FTA) was also evaluated. These radiographs were taken before the surgery and on postoperative day 21.

Simultaneously, knee flexion angles on TKA side, subjective pain level on TKA side and vertical knee forces (% body weight; BW) on TKA side during relaxed standing were also examined. Data evaluations were done both before and on postoperative day 21. Statistical difference between the data was evaluated using two-tailed Wilcoxon t-test. P-values of < 0.05 were considered as significant.

Methods

Thirty patients (25 Females and 5 Males) with knee osteoarthritis, 67 to 84 years old (mean 75), participated. All the subjects provided informed consent and the study was approved by our institution. The subjects were asked to step on the two scales and perform relaxed standing, placing each foot on each scale independently. Evaluations were divided into two categories; subjective and objective components. Subjective component was based on pain level, and objective component consisted of vertical knee force and knee flexion angle during relaxed standing. Namely, subjective pain level on TKA side, vertical knee forces (%BW) on TKA side, and knee flexion angles (degrees) on TKA side during relaxed standing, were examined. Each evaluation was done twice. Data evaluations were done pre- and post-operatively. Postoperative evaluations were done daily from postoperative day 3 to 21. Pain level, vertical knee force, and knee flexion angle were evaluated using visual analog scale (100 mm), same type of two scales, and goniometer, respectively. Vertical knee force (%BW) was defined as the ratio of weight bearing on TKA side to body weight in our study.

An average value of two trials was calculated. Values of preoperative measurements were used as controls. Statistical difference between the data was evaluated using two-tailed repeated-measures of analysis of variance. After a significant P value (< 0.05) was determined, a post hoc Bonferroni correction was performed to compare selected mean values, and P-values of < 0.05 was considered as significant.

Methods

This guide was applied consecutive 230 patients in primary THA. During planning, the distance from the acetabular edge to the reaming center and from the center to the perpendicular of the inter-teardrop line was measured on an anteroposterior (AP) X-ray. The reaming guide was adjusted depend on the reaming center by based planning. Acetabular reaming was performed with the process reamer.