Finite element and biomechanical analysis of risk factors for implant failure during tension band plating

Growth modulation for angular knee deformities: a practical guideline

PURPOSE OF REVIEW

This study aimed to review the established concepts and advances related to growth modulation for treating knee angular deformities. Although they are considered well tolerated procedures, careful indications and accurate techniques are necessary to ensure good results.

RECENT FINDINGS

In addition to general clinical and radiographic evaluations, new tools such as two-dimensional low-dose radiography and gait analysis have been used to clarify angular and torsional combinations and the impact of mild angulations on the knee joint. Temporary epiphysiodesis is commonly the choice, and it can be performed with different implants such as staples, tension band plates (TBP), percutaneous transphyseal screws (PETS), sutures, and screws.

SUMMARY

Considering its principles, TBP has been preferred for younger children. Cost can be a limitation, and research for alternative implants such as screws and nonabsorbable sutures indicate they might be an alternative in the future. In adolescents, PETS becomes an attractive alternative; however, its reversible character has been controversial, and further studies are needed to establish limits in younger patients.

Biomechanical Analysis of Arm Manipulation in Tai Chi

In order to explore the kinematics and muscle force characteristics of competitive Taijiquan arm manipulation, and solve the problems of arm trajectory and control in the process of manipulation, this study puts forward the sports biomechanical analysis of arm manipulation in competitive Taijiquan. The technical characteristics and muscle force characteristics of 15 athletes from the competitive Taijiquan team of Xi'an Institute of physical education were studied. Use Excel 2007 and SPSS17.0 to statistically analyze and process the original data. According to the actual needs, the data indicators are summarized. The combined movements of competitive Taijiquan arm manipulation are captured through high-speed photography, and the kinematic data are statistically analyzed, mainly from the two aspects of action amplitude change and action braking. The results show the action track length, relative track length, and action track length of each plane of the two combined hands. The order of the two combined action tracks is: combination 1 > combination 2, in which the action track in the sagittal plane is the longest in combination 1, and it can also be considered that the motion amplitude in the sagittal plane is the largest in combination 1. The average acceleration of group A in the first beat is 0.51 m/s² smaller than that of group B, and the value is 0.22 m/s² smaller. Therefore, the deceleration of group A is larger than that of group B, and the braking capacity of group A is slightly stronger than that of group B. In the second beat, the average acceleration of group B is 1.5722 m/s² larger than that of group A, and the value is 0.210 m/s² larger. The average acceleration of group A in the third, fourth, fifth, and sixth beats is 0.9, 3.728, 0.57, and 0.837 m/s² smaller than that of group B, and the values are 0.466, 0.174, 0.250, and 0.003 m/s² smaller, indicating that the braking capacity of group A in the third, fourth, fifth, sixth, and eighth beats is slightly stronger than that of group B. In the braking of each beat in combination 1 and combination 2 of group AB, the braking ability of arm manipulation of group A is stronger than that of group B. In competitive Taijiquan, the movement techniques of manipulation include: bouncing technology, braking technology, and control technology. For arm manipulation, athletes should have the ability of "braking" technology. In the correlation analysis of movement track length, RMS and I EMG, the score of athletes in group A is high, and there is no correlation between movement track length and RMS. There is a significant correlation between RMS and movement track length in group B, and the correlation degree is moderate. This shows that when the movement of group B athletes is completed, the muscles are in a state of tension, the movement skills are not mastered well, and the energy saving is not achieved. During training, we should pay more attention to the proprioception of muscles and form a correct way of muscle exertion.

Biomechanical Analysis of Staples for Epiphysiodesis

Limb asymmetry can, and often does, cause various health problems. Blount bone staples (clips) are used to correct such uneven growth. This article analyzes the performance of a biomechanical staple during bone (tibia) growth arrest. The staples considered in this study were made of 1.4441 stainless steel, the model of tibia consisted of two materials representing corticalis and spongiosis. Hooke’s law was used for modeling materials’ behaviors for finite element analysis (FEA). The maxima of stress and total staple displacement were evaluated using the finite element method and verification of the results, along with the determination of the maximum loading (growing) force that the staples are capable of withstanding, was performed experimentally. The presented method can be used to determine the safety and usability of staples for bone growth arrest. According to our results, the design of Blount staples considered in this paper is safe and suitable for orthopedic treatment.