Objective:To compare the clinical efficacy between our first generation and second generation dynamic anterior plate-screw system for quadrilateral area (DAPSQ) in the treatment of T-shaped acetabular fractures.Methods:A retrospective study was conducted of the 28 patients with T-shaped acetabular fractures who had been treated at Department of Orthopaedics, General Hospital of Central Theater Command from January 2008 to December 2019. They were divided into 2 groups according to fixation methods. Group A [15 patients, 11 males and 4 females, an age of (43.5±9.1) years] were treated with the first generation DAPSQ while Group B [13 patients, 8 males and 5 females, an age of (42.5±7.0) years] with the second generation DAPSQ. Operation time, intraoperative bleeding, fracture reduction, function of the affected hip and postoperative complications were recorded and compared between the 2 groups.Results:The 2 groups were comparable because there was no significant difference between them in the preoperative general data ( P>0.05). The 28 patients were followed up for 12 to 60 months (average, 35.0 months). The operation time [(193.9±33.3) min] and intraoperative bleeding [(830.8±177.4) mL] for Group B were significantly less than those for Group A [(231.3±40.0) min and (1,043.3±190.7) mL] ( P<0.05). In Group A, according to the Matta scoring, the fracture reduction was rated as excellent in 8 cases, good in 5 and poor in 2; in Group B, the fracture reduction was rated as excellent in 8 cases, good in 4 and poor in one. According to the modified Merle d'Aubigné & Postel scoring at the final follow-up, the function of the affected hip was rated as excellent in 9 cases, as good in 3, as fair in 2 and as poor in one in Group A while as excellent in 9 cases, as good in 2 and as fair in 2 in Group B. There were no statistically significant differences between the 2 groups in reduction quality or in the function of the affected hip ( P>0.05). Follow-up observed hip traumatic arthritis in 2 cases in Group A and in one in Group B. Conclusion:In the treatment of T-shaped acetabular fractures, compared with the first generation DAPSQ, the second generation DAPSQ can shorten operation time and decrease intraoperative bleeding significantly, though both achieve comparable functional outcomes.

Objective:To explore the effects of whole-body fatigue on the balance and ankle proprioception during drop landing of individuals with functional ankle instability(FAI)by comparing the differences in balance and pro-prioception between the FAI group and the control group before and after fatigue. Method:A total of 31 participants with unilateral FAI and 31 healthy participants were included in this study.A static balance test,dynamic balance test,and ankle proprioception test were conducted before and after fa-tigue.Sway distance(D)of the center of pressure(COP),root mean square of the COP(RMS),95％confi-dence ellipse area of the COP movements(95％AREA),normalized reach distance,and the area under the curve(AUC)were calculated and analyzed. Result:Before whole-body fatigue,the static balance,dynamic balance,and ankle proprioception during drop landing in FAI group were significantly lower than those in control group.After whole-body fatigue,the static balance,dynamic balance,and ankle proprioception during drop landing in the FAI group and control group decreased significantly(P＜0.05),and the increase of D,RMS and 95％AREA in FAI group were significant-ly larger than those in control group(P＜0.05),and the decrease of normalized reach distance in the postero-medial and posterolateral directions and AUC were significantly larger than those in control group(P＜0.05). Conclusion:Whole-body fatigue reduced the static balance,dynamic balance,and ankle proprioception,and the reduction was larger in FAI individuals than in healthy individuals.Therefore,whole-body fatigue may in-crease the risk of recurrent ankle sprain by reducing posture control and proprioception in FAI individuals.

Objective The reliability and validity of the SGGC-Net-based motion capture system(SGGC-Net system)and SIMI system for parsing walking gait were compared using a three-dimensional(3D)motion capture system(Vicon)with marker points as a reference standard.Methods Thirty healthy college students were recruited,and their gait characteristics while walking on a treadmill were analyzed.Kinematic data were collected using the Vicon system,and video data were collected synchronously using four cameras to obtain the right shoulder,elbow,hip,knee,and ankle joint angles.Reliability was assessed using intraclass correlation coefficients(ICCs)with 95％confidence intervals and standard error of measurement(SEM).Validity was assessed using multiple correlation coefficients(MCCs)and root mean square errors(RMSEs).Results The ICCs of the maximum and minimum 3D coordinate angles of the upper and lower limb joints of the SGGC-Net system ranged from 0.798-0.990 with an SEM of 0.04°-0.95°,and the ICCs of the SIMI system ranged from 0.650-0.967,with an SEM of 0.31°-1.24°.The ICCs of the SGGC-Net system were higher than those of the SIMI system for all joint angles except for the minimum hip and maximum knee angles.Compared to the joint angle curves derived from the SIMI system,the MCCs of the curves derived from the SGGC-Net system ranged from 0.945-0.996,with RMSEs of 1.44°-4.65°,and the multiple correlation coefficients of the SIMI system ranged from 0.815-0.986,with RMSEs of 2.56°-9.99°.The MCCs of the SGGC-Net system were greater than those of the SIMI system at all angles except for the ankle joint.The RMSEs of the SGGC-Net system were smaller than those of the SIMI system at all angles except for the ankle joints.Conclusions The SGGC-Net system has better reliability and validity than the SIMI system in most of the variables,and it has better repeatability and accuracy in analyzing walking gait.It can be applied to motion capture environments without marker points,such as technical analysis of athletes'movements and clinical gait analysis of special populations.

Objective To explore the effect of proprioceptive neuromuscular facilitation(PNF)on the knee abduction torque and vastus medialis-medial gastrocnemius(VM-MG)co-contraction index during walking among the old patients with medial compartment knee osteoarthritis. Methods From March to May,2022,32 old patients with medial compartment knee osteoarthritis in communities in Ji'nan were enrolled and randomly allocated to control group(n=16)and training group(n=16).The training group received PNF and the control group received home-based exercise,for six weeks.The knee abduction torque and VM-MG co-contraction index were measured using an infrared motion capture system synchronized with 3D force plate and electromyography system before and after treatment. Results Three cases in the control group and two cases in the training group dropped off.The first and the second peaks of knee abduction torque,and the VM-MG co-contraction index improved in the training group after treatment(|t|>2.460,P<0.05),and the first and the second peaks of knee abduction torque were better in the training group than in the control group(|t|>2.454,P<0.05). Conclusion PNF may optimize the load distribution between the medial and lateral compartments of the knee in patients with knee osteoarthritis.

BACKGROUND:Individuals with chronic ankle instability are prone to inversion ankle sprains during landing.Moderately increasing the foot toe-out angle during landing may reduce the occurrence of inversion ankle sprains,but no studies have directly demonstrated this effect. OBJECTIVE:To explore the effect of increased toe-out angle during landing on the peak inversion angle,peak angular velocity,and the time to peak inversion among individuals with and without chronic ankle instability. METHODS:A total of 60 participants were recruited for this study,including 30 individuals with chronic ankle instability and 30 without chronic ankle instability.The study utilized a simulated sprain apparatus for drop-landing tests,featuring a platform that could tilt forward by 24° and inward by 15°,thus simulating the foot position during an ankle inversion sprain.Participants were required to perform drop-landing tests under two landing conditions:natural landing and toe-out landing,with the latter involving a greater foot toe-out angle,over 150%more than the former.Kinematic data of participants were recorded using a 12-camera three-dimensional motion capture system.Data analysis was conducted using two-way repeated measures analysis of variance and Spearman correlation analysis. RESULTS AND CONCLUSION:(1)Significant main effects of condition were found for peak inversion angle during drop-landing(P<0.001,η2 p=0.270),peak inversion velocity(P=0.015,η2 p=0.098),and peak inversion time(P<0.001,η2 p=0.260);a significant main effect of group was found for peak inversion velocity(P=0.029,η2 p=0.080).(2)There were significant negative correlations between the foot toe-out angle at landing and the peak ankle inversion angle(P=0.021,r=-0.310;P=0.042,r=-0.278)as well as the peak inversion time(P=0.018,r=-0.312;P=0.021,r=-0.309)in both chronic ankle instability and non-chronic ankle instability groups.Moreover,a significant negative correlation was also found between the foot toe-out angle and peak inversion velocity in the chronic ankle instability group(P=0.021,r=-0.312).(3)It is indicated that increasing the foot toe-out angle at landing can reduce the peak inversion angle,peak inversion velocity,and the peak inversion time during landing in patients with chronic ankle instability and non-chronic ankle instability,thereby decreasing the risk of ankle inversion sprains.

Objective:To introduce the standard screw implantation methods and to analyze the biomechanical stability of the second-generation dynamic anterior plate-screw system for quadrilateral area (DAPSQ).Methods:Six adult formalin-preserved corpses were selected to make a complete pelvic specimen. Further, the left high double-column fracture models were made and randomly fixed with second-generation DAPSQ or anterior reconstruction titanium plate and 1/3 tube buttress-plate (ARTPB). The specimens of intact pelvis (IP) group, DAPSQ group and ARTPB group were fixed on a Zwick Z100 material machine and loaded vertically with 200 N, 300 N, 400 N, 500 N, 600 N, 700 N, and 800 N in a simulated sitting position, respectively. The axial displacement and strain changes in the anterior and posterior columns were tested in the three groups. The stiffness was calculated accordingly.Results:The axial compression displacement in the three groups showed an increase trend as well with the vertical load increased from 200 N to 800 N ( F=68.581, P<0.001; F=91.795, P<0.001; F=33.819, P=0.002). The axial displacement in ARTPB group was significantly larger than that in DAPSQ group and IP group ( P<0.05), while the difference between DAPSQ and IP groups was not significant ( P>0.05). Under the vertical load of 600 N, the pelvic axial stiffness of IP group, DAPSQ group, and ARTPB group were 220.72±70.33 N/mm, 185.68±48.49 N/mm and 135.83±60.58 N/mm, respectively. The axial stiffness of ARTPB group was significantly lower than that in DAPSQ group and IP group ( t=5.345, P=0.003; t=6.443, P=0.001), while the difference between DAPSQ and IP groups was not significant ( t=2.138, P=0.086). There were no significant differences of the strain values in anterior column among the three groups during the load increasing from 200 N to 800 N ( P>0.05). With the load increasing from 500 N to 800 N, the strain values of the posterior column in ARTPB group were significantly greater than those of IP and DAPSQ groups ( P<0.05). However, the differences between IP and DAPSQ groups were not statistically significant in strain values of the posterior column ( P>0.05). Conclusion:Compared with anterior reconstruction titanium plate and 1/3 tube buttress-plate, acetabular double-column fracture model fixed with the second-generation DAPSQ has less axial compression displacement but with greater axial stiffness. The stress change in the posterior columns of the acetabulum is like in IP. Therefore, the second-generation DAPSQ has reliable biomechanical stability.

Objective To explore the impacts of proprioception, cutaneous sensitivity and strength on dynamic and static postural stability.Methods From June to November, 2020, a total of 164 elderly participated in this study. Independent parameters included proprioception of knee flexion/extension and ankle dorsi/plantar flexion with proprioception measurement; the cutaneous sensitivity of great toe, first and fifth metatarsals, arch, and heel with monofilament; and strength of ankle dorsi/plantar flexion and hip abduction with isokinetic test. The Berg Balance Scale (BBS) and center of pressure (COP)-based postural stability tests were conducted to represent dynamic and static postural stability. Exploratory factor and multivariable linear regression analyses were used to explore the relationship of each generated factor to postural stability outcomes.Results Proprioception was significantly correlated to the score of BBS (r=-0.449, P<0.001) and the root mean square (RMS) of COP in mediolateral direction (r=0.254, P=0.004). Cutaneous sensitivity was significantly correlated to the RMS of COP in the anteroposterior direction (r=0.281, P=0.002). Strength was significantly correlated to the score of BBS (r=0.493, P<0.001).Conclusion Proprioception and strength are related to dynamic postural stability, while proprioception and cutaneous sensitivity are associated with static postural stability.