Sex differences in three-dimensional talocrural and subtalar joint kinematics during stance phase in healthy young adults.

The ankle joint, including the talocrural and subtalar joints, plays an important role in human locomotion. Sex differences in walking patterns among young and old adults have been studied; however, little information exists on sex-based variations in talocrural and subtalar joint kinematics during walking. Thus, the purpose of this study was to investigate sex-based differences in the talocrural and subtalar joint kinematics during walking. We obtained lateral fluoroscopic images from 10 male and 7 female healthy volunteers during stance phase, and determined the three-dimensional bone orientations using 3D-2D model-image registration techniques to compare sex-specific differences. The orientation of the tibia, talus, and calcaneus were comparable in the static reference position. Sex-based differences in the range of motion were observed in talocrural dorsi/plantar flexion, subtalar eversion/inversion and subtalar external/internal rotation while walking. The ranges of motion in talocrural dorsi/plantar flexion (male, 13 ±â€¯4°; female, 17 ±â€¯3°), subtalar eversion/inversion (male, 8 ±â€¯3°; female, 11 ±â€¯3°) and subtalar external/internal rotation (male, 5 ±â€¯2°; female, 7 ±â€¯2°) were significantly larger in females than in males. Differences in rearfoot kinematics between males and females may reflect anatomic, physiologic and locomotor differences. Greater bone rotations in the female hindfoot may predispose women to different pathologies, or merit different treatments, than men based upon subtalar and talocrural kinematics during gait.

Matched comparison of kinematics in knees with mild and severe varus deformity using fixed- and mobile-bearing total knee arthroplasty.

BACKGROUND: We examined knee kinematics in three 16-knee cohorts with the same implant design to clarify the influence of bearing mobility and preoperative deformity on the kinematics of posterior-stabilized knee arthroplasty. Compared to knees with mild deformity and a fixed-bearing implant, we hypothesized that a matched group of knees with mobile-bearing prostheses would show greater tibial axial rotation. We hypothesized that knees with the same fixed-bearing implant, but severe preoperative deformity, would have less axial rotation. METHODS: A total of 58 knees in 48 patients were involved in this study from a consecutive single-surgeon total knee arthroplasty series. Sixteen knees received mobile-bearing prostheses, and a best-matched cohort of knees with fixed-bearing implants was selected. The 16 fixed-bearing knees with most severe preoperative deformity were selected as a third group. All knees were examined at least 1.5 years after surgery. Flexion, femoral external rotation, anteroposterior translation of both femoral condyles during squatting and deep knee flexion activities were evaluated using model-image registration techniques. FINDINGS: We found some statistically significant, but small differences among the three groups in dynamic and static knee kinematics. In squatting, total femoral rotation for knees with fixed- and mobile-bearing implants, and knees with fixed-bearing implants after severe preoperative varus deformity, was not significantly different. [7° (SD3°), 9° (SD3°), 8° (SD3°), respectively, P=0.08]. INTERPRETATION: Similar kinematic results for knees with different tibial bearing surfaces and preoperative deformities indicate a robust treatment with this posterior stabilized implant. However, knees did not exhibit normal femoral rotations or functional flexion ranges.

Fluoroscopic and gait analysis of the functional performance in stair ascent of two total knee replacement designs.

Understanding total knee replacement mechanics and their influence on patient mobility requires accurate analysis of knee joint kinematics and traditional full body kinematics and kinetics. Three-dimensional fluoroscopic and gait analysis techniques were carried out on patients with either mobile bearing or posterior stabilized knee prostheses during stair ascent. Statistically significant correlation was found between knee flexion at foot strike and the position of the mid-condylar contact points, and between maximum knee adduction moment and corresponding lateral trunk tilt. A more complete and powerful assessment of the functional performances of different TKR designs can be performed in-vivo by combining gait and fluoroscopic analyses.