ABSTRACT
Sarcopenia, referred to as myopenia, is a systemic syndrome characterized by decreased muscle mass and muscle strength, and decline of motor function.The elderly are a high incidence group of myopenia.With the aging of the world's population becoming increasingly severe, the incidence rate of sarcopenia has also increased, which has brought a heavy burden to the elderly family and society, and has become an important social health problem for the elderly.At present, there are more and more researches on sarcopenia, but the pathogenic factors of sarcopenia are complex and diverse.The prevention and treatment of sarcopenia still need to be further explored and studied.The establishment of an ideal animal model is the key premise and basis for the related research of sarcopenia.In this paper, the different modeling methods, advantages and disadvantages as well as the scope of application of sarcopenia animal models are described, which can provide reference and help for the subsequent animal experimental research of sarcopenia.
ABSTRACT
A 3D printed patient-specific surgical guide plate is an auxiliary device made with the help of computer-aided design and 3D printing technology according to a surgical plan. It is used in reduction and internal fixation of fracture and specific corrective osteotomy as well. It is very adaptive as it has been widely used in trauma surgery, joint surgery and spine surgery, as well as in surgical treatment of bone tumors. Digital orthopedic technology is an important means to realize orthopedic precision medicine. This paper reviews the technical advantages, applications, main problems and future prospects of 3D printed patient-specific surgical guide plates in the field of orthopedics based on the recent literature.
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Objective To investigate biomechanical characteristics of femoral neck fracture with different reduction qualities. Methods Three cases of Sawbones artificial femoral models were selected, and two cases of Pauwel III femoral neck fracture were modeled. Three cannulated screws were inserted into the models in the form of inverted triangle to fix the fracture. Two cases maintained different reduction qualities (defined as Model 1 and Model 2). In the 3 third case, no modeling operation was performed (defined as intact model). Then the strain gauges were respectively pasted on regions of interest of the 3 femoral models. Finally, the femur model was applied with the vertical load on mechanical testing machine. Results When the displacement of femoral head reached 4 mm, the average load of intact model, Model 1 and Model 2 was (236.30±5.35), (196.57±3.56), (69.50±2.95) N, showing significant differences. When the displacement of femoral head reached 5 mm, the average load of intact model, Model 1 and Model 2 was (276.7±3.40)，(232.93±2.64)，(80.83±4.54) N, showing significant differences. Conclusions The lower the reduction quality of the femoral neck fracture, the weaker the ability of the femur to bear stress, the higher the probability of nonunion, re-fracture and femoral head necrosis in the process of postoperative rehabilitation.
ABSTRACT
Posttraumatic ankle arthritis caused by trauma, a common articular disease, mainly destroys the biomechanical balance of the ankle joint and results in degeneration of the joint.It often occurs in young people, leading to articular pain and stiffness and other symptoms which may deteriorate to end-stage posttrau-matic ankle arthritis with no intervention.At present, a variety of therapies are available for the disease. However, no domestic literature has addressed the choice and application of its treatment methods.To be useful in clinic, this review deals with the etiology, diagnosis and treatment (including choice, efficacy, indications and contraindications) of the disease.
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Objective To study the effects of natural walking on human plantar pressure and surface electromyogrphy (sEMG) of lower limbs.Methods 28 healthy male volunteers were enrolled,and their plantar pressure and surface electromyogrphy related parameters were measured before and after 30 min natural walking.These parameters not only include plantar peak pressure and peak impulse,but also include time domain parameter (integral electromyogrphy,iEMG) and frequency domain parameter (mean power frequency,MPF) of tibial anterior muscle,gastrocnemius,femoral rectus,and biceps femoris muscle.The correlations between peak pressure and height as well as weight were analyzed.Results The feature parameters showed significant difference between left and right foot before and after 30 min natural walking (all P＜0.05).The differences of peak pressure and peak impulse values between left and right limb were found in different plantar areas.In the metatarsal areas M3,M4 and M5,the pressure parameters of left side were larger than those of right side (all P＜0.05).The values of iEMG and sEMG of left limb were larger than those of right side in tibialis anterior,gastrocnemius,rectus femoris and biceps femoris (all P＜ 0.05).The MPF values of sEMG of left limb were larger than those of right side in tibialis anterior and gastrocnemius (all P＜0.05).After 30 min natural walking,the peak pressures in right toe2-5 areas were decreased (all P＜0.05),the differences of iEMG of sEMG in all muscles were not significantly,and the MPF value of sEMG in left rectus femoris was decreased.Weak correlations were observed between peak pressure and height as well as weight.Conclusions The differences of left and right lower limbs were found in plantar pressure and sEMG values during natural walking.The results showed that 30 min natural walking did not cause significant stress-related fatigue in plantar areas.Therefore,the stability of gait can be maintained for a 30 min natural walking.However,that may lead to fatigue of the femoris rectus in the left limb.