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Objective@#To setup a custom-made gait simulator, and to provide an efficient tool for biomechanics research of ankle and foot.@*Methods@#From November 2017 to April 2018, a total of 6 fresh frozen specimens of the foot and ankle were collected. The donated specimens, free of diseases in the foot and ankle part, were from the Department of Anatomy, Shanghai Medical College of Fudan University. Donors were 3 males and 3 females, aged from 48 to 69 years old, with an average age of 58.8 years old. The nine tendons in the foot were divided into 4 bundles, including anterior group comprised of tibialis anterior (TA), extensor hallucis longus (EHL) and extensor digitorum longus (EDL). Posterior group comprised of Achilles's tendon (AT). Medial group comprised of tibialis posterior (TP), flexor hallucis longus (FHL), and flexor digitorum longus (FDL). Lateral group comprised of peroneus brevis (PB) and peroneus longus (PL). A custom-made gait simulator was set up by using four independent electro motors to actuate 4 bands of tendons in the foot and another six motors to control tibia to achieve 6 degree-freedom parallel mechanism. And a hydraulic machine was used to provide axial pressure along tibia. Gait cycle of six fresh frozen cadaver feet was reproduced using this machine, and the kinematics data of ankle movement and ground reaction force (GRF) data was collected. By comparing the data above with the normal human gait data, the simulation results were analyzed to explore the clinical usage of this machine.@*Results@#On the sagittal plane, the ankle appeared to plantarflexion at the beginning of gait, and then turned to dorsiflexion after the max plantar flexion (about 10°) at 18% of gait cycle. At the 40% gait cycle, ankle joint was in neutral position and reached its max dorsiflexion (about 22°) at 83% gait cycle. On the coronal plane, ankle joint appeared inversion at the beginning and eversion afterwards with 10° range of change. On the horizontal plane, movement of ankle joint was small. Results showed that the first peak of vertical ground reaction force can reach to 1.1-1.3 times of bodyweight at 25% of gait cycle and the second peak appeared little lower at 70% of gait cycle. The GRF in posterior direction reached its peak at 30%, and then turned to anterior with its peak at 83% gait cycle. The GRF had small variation at the internal to external direction.All of the coefficients of multiple correlations (CMC) of GRF and ankle joint movements were close to or greater than 0.90.@*Conclusion@#This custom-made gait simulator has good gait simulation ability with high intra repeatability in respect of ankle rotation and ground reaction force, and can satisfy the request for ankle and foot biomechanics research.
ABSTRACT
Objective To setup a custom?made gait simulator, and to provide an efficient tool for biomechanics research of ankle and foot. Methods From November 2017 to April 2018, a total of 6 fresh frozen specimens of the foot and ankle were collected. The donated specimens, free of diseases in the foot and ankle part, were from the Department of Anatomy, Shanghai Medical College of Fudan University. Donors were 3 males and 3 females, aged from 48 to 69 years old, with an average age of 58.8 years old. The nine tendons in the foot were divided into 4 bundles, including anterior group comprised of tibialis anterior (TA), extensor hallucis longus (EHL) and extensor digitorum longus (EDL). Posterior group comprised of Achilles's tendon (AT). Medial group comprised of tibialis posterior (TP), flexor hallucis longus (FHL), and flexor digitorum longus (FDL). Lateral group comprised of peroneus brevis (PB) and peroneus longus (PL). A custom?made gait simulator was set up by using four independent electro motors to actuate 4 bands of tendons in the foot and another six motors to control tibia to achieve 6 degree?freedom parallel mechanism. And a hydraulic machine was used to provide axial pressure along tibia. Gait cycle of six fresh frozen cadaver feet was reproduced using this machine, and the kinematics data of ankle movement and ground reaction force (GRF) data was collected. By comparing the data above with the normal human gait data, the simulation results were analyzed to explore the clinical usage of this machine. Results On the sagittal plane, the ankle appeared to plantarflexion at the beginning of gait, and then turned to dor?siflexion after the max plantar flexion (about 10°) at 18% of gait cycle. At the 40% gait cycle, ankle joint was in neutral position and reached its max dorsiflexion (about 22°) at 83% gait cycle. On the coronal plane, ankle joint appeared inversion at the begin?ning and eversion afterwards with 10° range of change. On the horizontal plane, movement of ankle joint was small. Results showed that the first peak of vertical ground reaction force can reach to 1.1-1.3 times of bodyweight at 25% of gait cycle and the second peak appeared little lower at 70% of gait cycle. The GRF in posterior direction reached its peak at 30%, and then turned to anterior with its peak at 83% gait cycle. The GRF had small variation at the internal to external direction.All of the coefficients of multiple correlations (CMC) of GRF and ankle joint movements were close to or greater than 0.90. Conclusion This custom?made gait simulator has good gait simulation ability with high intra repeatability in respect of ankle rotation and ground reaction force, and can satisfy the request for ankle and foot biomechanics research.
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Objective To explore the mid-term efficacy of derotation of talus and medial column fusion for stage Ⅱ-Ⅴ Müller-Weiss disease (MWD).Methods Data of thirty-six patients (38 feet) with MWD treated by derotation of talus and talonavicular (tTN) or talonavicular-cuneiform (TNC) arthrodesis in our center during January 2008 to December 2016 were retrospectively analyzed.There were 3 males (3 feet) and 33 females (35 feet) with an average age of 54.0±9.2 years old (range,32-80 years old);there were 11 right feet and 27 left feet.According to Maceira and Rochera staging system,there were 9 stage Ⅱ cases,11 stage Ⅲ cases,10 stage Ⅳ cases and 8 stage Ⅴ cases.The external rotation of talus was intensively focused.After the TN articular surface was debrided,an "H" shape plate and a hollow lag screw were used to firmly fix the TN or TNC joint.American Orthopaedic Foot and Ankle Society Scale (AOFAS),visual analog scale (VAS) and relative radiological parameters were evaluated preoperatively and during follow-up.Results The mean follow-up duration was 37.2 months (range,25-113 months).The latest follow-up showed satisfactory outcomes.Overall,AOFAS score was improved from 41.3± 11.3 points (range,20-56 points) preoperatively to 85.5±7.1 points (range,68-100 points) postoperatively (Z=5.16,P＜ 0.001),and the VAS score was reduced from 5.6±1.5 points (range,3-8 points) preoperatively to 0.8± 1.2 points (range,0-4 points) postoperatively (Z=5.19,P＜ 0.001).These differences of functional score and pain evaluation were statistically significant.The Tomeno-Méary angle decreased from-6.6°± 12.2° to 0.5°± 2.9° (Z=3.43,P=0.001);the calcaneal pitch angle increased from 13.5°±3.9° to 22.1 °±3.4°(t=10.12,P＜ 0.001),and the talarnavicular coverage angle decreased from 27.1°±5.9° to 7.6°±3.3°(Z=5.16,P＜ 0.001).The AP talar-first metatarsal angle decreased from-16.0°±10.7° to-7.0°±8.5°(t=5.49,P＜ 0.001).The differences of radiological parameters were statistically significant.Conclusion The mid-term results showed that the TN or TNC joint fusion could achieve a favorable clinical and radiological outcome for MWD patients.Even for the patients with severe deformities (stage Ⅱ-Ⅴ),such treatment strategy could also achieve satisfactory deformity correction and functional improvement.Intraoperative restoration of talus rotation is the key to normal alignment of the subtalar joint / TN joint.
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Objective@#To explore the mid-term efficacy of derotation of talus and medial column fusion for stage II-V Müller-Weiss disease (MWD).@*Methods@#Data of thirty-six patients (38 feet) with MWD treated by derotation of talus and talona-vicular (TN) or talonavicular-cuneiform (TNC) arthrodesis in our center during January 2008 to December 2016 were retrospective-ly analyzed. There were 3 males (3 feet) and 33 females (35 feet) with an average age of 54.0±9.2 years old (range, 32-80 years old); there were 11 right feet and 27 left feet. According to Maceira and Rochera staging system, there were 9 stage II cases, 11 stage III cases, 10 stage IV cases and 8 stage V cases. The external rotation of talus was intensively focused. After the TN articular surface was debrided, an "H" shape plate and a hollow lag screw were used to firmly fix the TN or TNC joint. American Orthopae-dic Foot and Ankle Society Scale (AOFAS), visual analog scale (VAS) and relative radiological parameters were evaluated preoper-atively and during follow-up.@*Results@#The mean follow-up duration was 37.2 months (range, 25-113 months). The latest follow-up showed satisfactory outcomes. Overall, AOFAS score was improved from 41.3±11.3 points (range, 20-56 points) preoperatively to 85.5±7.1 points (range, 68-100 points) postoperatively (Z=5.16, P< 0.001), and the VAS score was reduced from 5.6±1.5 points (range, 3-8 points) preoperatively to 0.8±1.2 points (range, 0-4 points) postoperatively (Z=5.19, P< 0.001). These differences of functional score and pain evaluation were statistically significant. The Tomeno-Méary angle decreased from-6.6°±12.2° to 0.5°±2.9° (Z=3.43, P=0.001); the calcaneal pitch angle increased from 13.5°±3.9° to 22.1°±3.4°(t=10.12, P< 0.001), and the talarnavic-ular coverage angle decreased from 27.1°±5.9° to 7.6°±3.3°(Z=5.16, P< 0.001). The AP talar-first metatarsal angle decreased from-16.0°±10.7° to-7.0°±8.5°(t=5.49, P< 0.001). The differences of radiological parameters were statistically significant.@*Conclusion@#The mid-term results showed that the TN or TNC joint fusion could achieve a favorable clinical and radiological outcome for MWD patients. Even for the patients with severe deformities (stage II-V), such treatment strategy could also achieve satisfacto-ry deformity correction and functional improvement. Intraoperative restoration of talus rotation is the key to normal alignment of the subtalar joint/TN joint.
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Objective:To explore whether there will be attentional bias under the condition of fear,disgust and positive emotional arousal. Methods:Totally 96 college students were selected as participants in this study,inclu-ding 60 males and 36 femalesaged 18-22 years. Affective priming videos were adopted to prime participants'emo-tion (dread,disgust,joviality),and then they named the color of the cognitive words (positive words,negative words,neutral words)as quickly and accurately as possible. Reaction time and correctness were recorded. E-prime was adopted to write the experimental program. The reaction time for neutral words was baseline. Results:The aver-age reaction time (RT)of color-naming tasks of negative words were shorter than that of neutral words after fright-ening affective priming[(648 ±118)ms vs. (743 ±124)ms,P<0. 01]. Furthermore,the average RT of color-na-ming tasks of positive words were also shorter than that of neutral after frightening affective priming[(683 ±123) ms vs. (743 ±124)ms,P<0. 05]. The average RT of color-naming tasks of negative words were shorter than that of neutral words after disgusting affective priming[(579 ±86)ms vs. (720 ±101 )ms;P<0. 01 ]. Moreover,the av-erage RT of color-naming tasks of positive words were shorter than that of neutral words after delighted affective priming[(634 ±122)ms vs. (716 ±141)ms;P<0. 01]. Furthermore,the average RT of disgusting priming group-were shorter than the frightening priming grouptowards negative information[(579 ±86)ms vs. (648 ±118)ms,P<0. 05 ]. Conclusion:It suggests that the youth perform more obvious attentional bias towards negative information after disgusting affective priming than the frightening one. Frightening affective priming could evidently induce the attentional bias on positive information.