Title: Changes of stabilization ability and sensation of the foot after ankle injury by volleyball players Objectives: To examine if volleyball players have any changes of stabilization ability and afferent function of the foot, using examination of stabilization ability and afferent function examination of the foot after ankle injury. To discover if any interrelated connections exist between stabilization ability and afferent function of the foot after ankle injury by volleyball players. Methods: We used a single-leg stance to examine postural control. We performed a common neurological examination (two-point discrimination, graphestesia, kinesthesia and vibration sense) to examine afferent function - superficial sensation and deep sensation with two-point esthesiometer, tuning-fork, and blunt object. Results: Stabilization ability after ankle injury using a single-leg stance examination deteriorated for 62.5% probands. Afferent function of the foot after ankle injury wasn't significantly impacted. Only two-point discrimination in the middle of the instep injured foot (area Lisfranc joint) decreased by 62.5% probands. Graphestesia, kinesthesia and vibration sense examination didn't show significant changes of afferent function after distorsion injury of the ankle. A change of stabilization ability...

abstract: It has been repeatedly shown that females have lower stability and increased risk of ankle injury when compared to males participating in similar sports activities (e.g., basketball and soccer), yet sex differences in neuromuscular control of the ankle, including the modulation of ankle stiffness, and their contribution to stability remain unknown. To identify sex differences in human ankle stiffness, this study quantified 2- dimensional (2D) ankle stiffness in 20 young, healthy men and 20 young, healthy women during upright standing over a range of tasks, specifically, ankle muscle co-contraction tasks (4 levels up to 20% maximum voluntary co-contraction of ankle muscles), weight-bearing tasks (4 levels up to 90% of body weight), and ankle torque generation tasks accomplished by maintaining offset center-of-pressure (5 levels up to +6 cm to the center-of-pressure during quiet standing). A dual-axial robotic platform, capable of perturbing the ankle in both the sagittal and frontal planes and measuring the corresponding ankle torques, was used to reliably quantify the 2D ankle stiffness during upright standing. In all task conditions and in both planes of ankle motion, ankle stiffness in males was consistently greater than that in females. Among all 26 experimental conditions, all but 2 conditions in the frontal plane showed statistically significant sex differences. Further analysis on the normalized ankle stiffness scaled by weight times height suggests that while sex differences in ankle stiffness in the sagittal plane could be explained by sex differences in anthropometric factors as well as neuromuscular factors, the differences in the frontal plane could be mostly explained by anthropometric factors. This study also demonstrates that the sex differences in the sagittal plane were significantly higher as compared to those in the frontal plane. The results indicate that females have lower ankle stiffness during upright standing thereby providing the neuromuscular basis for further investigations on the correlation of ankle stiffness and the higher risk of ankle injury in females. / Dissertation/Thesis / Masters Thesis Biomedical Engineering 2020

Injuries to the lower extremity are frequent and severe in frontal automotive collisions, often leading to pain and long-term impairment. Most injury criteria developed for the lower extremity are conducted with the foot and ankle in a neutral posture, do not take into account footwear, and assess injury risk to the entire lower extremity at the tibia. An instrumented boot, designed to address some of these challenges, was calibrated over a range of impact energies expected in frontal automotive collisions. A dynamic calibration method was developed to convert changes in voltage across a piezoresistive polymer to the applied axial force. The instrumented boot was then used to examine the axial impact response of two commonly used Anthropomorphic Test Device (ATD) lower legs, under altered ankle postures. Both posture and ATD model were found to affect the load distribution on the foot, highlighting the need to establish injury limits for non-neutral postures as well as selecting the appropriate ATD model. The instrumented boot provided regional loading information that was not reflected in standard industry metrics, emphasizing the importance of increased instrumentation in this area. A technique was developed for mounting cadaveric feet to ATD tibia shafts, in order to gather industry-relevant load data while examining the impact characteristics of the foot. Load data were collected at the plantar surface of the foot using the instrumented boot, as well as the tibia load cells in the ATD shaft, that highlighted differences in load transmission through cadaveric and ATD feet. Understanding the impact characteristics of ATDs under non-standard ankle postures as well as examining the load transmission through cadaveric feet highlighted some shortcomings with current injury assessment techniques. The results of this work can be used to improve future collision testing practices, in order to reduce the incidence of lower extremity injuries. / Thesis / Master of Applied Science (MASc) / Foot and ankle injuries are common in automotive collisions and often lead to pain and long-term impairment. Experimental work on these types of injuries is traditionally conducted with the foot and ankle positioned in a neutral ankle posture, which does not reflect the range of ankle postures individuals may assume in a car crash. The purpose of this work was to use biomechanical tools to assess foot/ankle injury risk. Impact testing was performed on two commonly used crash test dummy lower legs in conditions relevant to those experienced in car crashes. A technique was developed to mount cadaveric feet to crash test dummy tibias to gather injury information of the foot, while also collecting load data in the tibia shaft – relevant metrics for industry crash testing. The results of this work outline the shortcomings of traditional injury assessment methods and may be used to improve future practices.

An estimated 23,000 ankle injuries occur every day in the U.S. Ankle sprains account for 85% of all ankle injuries and inversion ankle sprains account for 85% of all ankle sprains. There is growing evidence that suggests gender and fatigue may increase the risk for inversion ankle sprains. Investigating the effects of fatigue and gender on peroneal reflex response after ankle inversion may help explain the differences in sprain rates with fatigue and gender. Therefore, the purpose of this study was to investigate the effects of fatigue and gender on peroneus brevis and peroneus longus reflexes after ankle inversion. A "trap-door" platform was used to elicit peroneal reflexes from sixteen males and fifteen females by suddenly inverting the ankle to 20°. Five unfatigued peroneal reflex measurements were performed before and after a fatigue protocol that attempted to fatigue the ankle evertors over 12 minutes to 75% of the unfatigued MVC torque. Results showed that reflex delay was not affected by fatigue, gender, or their interaction. PL reflex amplitude was not affected by fatigue or gender but was affected by their interaction. Results showed that PL reflex amplitude decreased by 11.3% in males and increased 22.1% in females with fatigue. A secondary analysis attempted to rule out extraneous factors that could have contributed to the differences in reflex response, but no experimental explanations were found. The differences in PL reflex amplitude were attributed to biomechanical, physiological, and anatomical differences between males and females. / Master of Science

Die Einrichtungen der Verkehrsunfallforschung Hannover und (ab 1999) Dresden registrierten 736 Beinverletzungen eines Schweregrades AIS ≥ 2 im Zeitraum von 1983 bis März 2007. 174 dieser Verletzungen (23,6 %) waren Frakturen und Luxationen des Fußes und des oberen Sprunggelenkes. Es waren 149 Füße von 141 Frontinsassen (140 PKW) betroffen. Die Insassen untergliederten sich in 117 Fahrer und 24 Beifahrer. Das durchschnittliche Alter der Insassen betrug 38.5 ± 16.8 Jahre. Die häufigste Verletzung war die Fraktur des oberen Sprunggelenkes (n=82; 80 Malleolarfrakturen, 2 Pilonfrakturen). 34 Frakturen und Luxationen betrafen den Rückfuß (5 Talus- und 26 Calcaneusfrakturen, 2 subtalare Luxationen, 1 subtotale Amputation), 16 den Mittfuß (4 Navicularefrakturen, 5 Cuboidfrakturen, 3 Cuneiformefrakturen, 2 Chopart-Gelenksluxationen, 1 subtotale Amputation, 1 schweres Decollement) und 39 den Vorfuß (Metatarsalefrakturen). Offene Frakturen wurden nur in 3 Fällen registriert (2 Malleolarfrakturen, 1 Metatarsalefraktur). In 10 Fällen wurden beide Füße verletzt. 33 Insassen (23,4 %) waren polytraumatisiert, davon starben 17. 81 % der Insassen waren angeschnallt. Die verunfallten PKW wurden in prä- (Baujahr 1997 und älter) und post-EuroNCAP- (Baujahr 1998 und jünger) Fahrzeuge unterteilt. Die meisten Fußverletzungen fanden sich in prä-EuroNCAP-Autos. Die meisten Insassen befanden sich in Fahrzeugen der unteren Mittelklasse (40 Fahrer und 9 Beifahrer) und der Mittelklasse (27 Fahrer und 7 Beifahrer). 49 der 140 Unfälle ereigneten sich auf Landes- bzw. Kreisstraßen, 26 auf Bundesstraßen und 13 auf Autobahnen. Es wurden überwiegend Frontalzusammenstöße beobachtet. Zwischen den verletzten Fußregionen fanden sich keine signifikanten Unterschiede hinsichtlich der Delta v- und EES-Werte, es ergab sich aber ein Trend zu höheren Delta v- und EES-Werten bei neueren PKW (post-EuroNCAP). Die Häufigkeit von Fußverletzungen stieg linear mit steigendem Delta v-Wert, oberhalb eines Delta v-Wertes von 55 km/h kam es nur noch in prä-EuroNCAP-Autos zu einem weiteren linearen Anstieg, während post-EuroNCAP-Fahrzeuge keinen weiteren Anstieg der Verletzungshäufigkeit zeigten. Die Fußraumintrusion zeigte keine signifikanten Unterschiede zwischen den einzelnen Fußregionen, jedoch zeigte sich in post-EuroNCAP-Fahrzeugen ein Trend zu höheren Intrusionswerten. Zwischen den einzelnen Fahrzeugklassen zeigten sich keine Unterschiede in der Fußraumintrusion. Nur 29 der 174 Frakturen und Luxationen des Fußes und des oberen Sprunggelenkes wurden in post-EuroNCAP-Fahrzeugen registiert, die überwiegende Zahl dieser Verletzungen (n=145) ereignete sich in prä-EuroNCAP-Fahrzeugen. Bei Betrachtung des AIS2008-assoziierten FCI (functional capacity index) für die Fußregion zeigte sich eine geringere Wahrscheinlichkeit einer dauerhaften Behinderung in post-EuroNCAP-Fahrzeugen bei gleichem Delta v-Wert. / The accident research of Hanover and (from 1999 on) Dresden registered 736 leg injuries (AIS ≥ 2) from 1983 to March 2007. 174 of these injuries (23.6 %) were fractures or dislocations of foot and ankle. 149 feet of 141 front seat car occupants in 140 cars were affected. Of these 117 were drivers, 24 were front seat passengers. The mean age of occupants was 38.5 ± 16.8 years. Ankle fractures were the most frequent injury (n = 82; 80 malleolar fractures, 2 pilon fractures). 34 fractures and dislocations affected the hindfoot (5 talus and 26 calcaneal fractures, 2 subtalar dislocations and 1 subtotal amputation) , 16 to midfoot (4 navicular fractures, 5 cuboid fractures, 3 fractures of cuneiformia, 2 dislocations of chopart joint, 1 subtotal amputation, and one severe decollement) and 39 the forefoot (metatarsal fractures). Open fractures were seldom seen (2 malleolar fractures, 1 metatarsal fracture). Both feet were injured in 10 cases. 33 occupants (23.4 %) were polytaumatic had a polytrauma, 17 of them died. 81 percent of the occupants were belted. The cars were divided in pre EuroNCAP (year of manufacture 1997 and older) and post EuroNCAP cars (year of manufacture 1998 and newer). Most of the foot injuries were seen in pre EuroNCAP cars. Most of the occupants sat in compact cars (40 drivers and 9 front seat passengers) and large family cars (27 drivers and 7 co-drivers). 49 of 140 accidents occurred on country roads, 26 on main roads and 13 on motorways. The crash direction was mostly frontal. Generally were found no differences of delta v- and EES-level between the injured foot regions, but divided into pre- and post-EuroNCAP cars there was a tendency to higher delta v- and EES-levels in newer cars. The frequency of foot injuries increased linearly with increasing delta v-level; but above delta v-level of 55 km/h the linear increase only was seen in pre-EuroNCAP cars, post-EuroNCAP cars showed no further increase of injuries. The footwell intrusion showed no difference between the injured foot regions but post-EuroNCAP cars had a tendency to higher footwell intrusion. There were no differences in footwell intrusion between the car types. Only 29 of 174 fractures or dislocations of foot and ankle were seen in post-EuroNCAP cars, the predominate number of these injuries (n = 145) were noticed in pre-EuroNCAP cars. A lower probability of long-term impairment was found in post-EuroNCAP cars for equal delta v levels, using the AIS2008 associated Functional Capacity Index (FCI) for the foot region.

Die Einrichtungen der Verkehrsunfallforschung Hannover und (ab 1999) Dresden registrierten 736 Beinverletzungen eines Schweregrades AIS ≥ 2 im Zeitraum von 1983 bis März 2007. 174 dieser Verletzungen (23,6 %) waren Frakturen und Luxationen des Fußes und des oberen Sprunggelenkes. Es waren 149 Füße von 141 Frontinsassen (140 PKW) betroffen. Die Insassen untergliederten sich in 117 Fahrer und 24 Beifahrer. Das durchschnittliche Alter der Insassen betrug 38.5 ± 16.8 Jahre. Die häufigste Verletzung war die Fraktur des oberen Sprunggelenkes (n=82; 80 Malleolarfrakturen, 2 Pilonfrakturen). 34 Frakturen und Luxationen betrafen den Rückfuß (5 Talus- und 26 Calcaneusfrakturen, 2 subtalare Luxationen, 1 subtotale Amputation), 16 den Mittfuß (4 Navicularefrakturen, 5 Cuboidfrakturen, 3 Cuneiformefrakturen, 2 Chopart-Gelenksluxationen, 1 subtotale Amputation, 1 schweres Decollement) und 39 den Vorfuß (Metatarsalefrakturen). Offene Frakturen wurden nur in 3 Fällen registriert (2 Malleolarfrakturen, 1 Metatarsalefraktur). In 10 Fällen wurden beide Füße verletzt. 33 Insassen (23,4 %) waren polytraumatisiert, davon starben 17. 81 % der Insassen waren angeschnallt. Die verunfallten PKW wurden in prä- (Baujahr 1997 und älter) und post-EuroNCAP- (Baujahr 1998 und jünger) Fahrzeuge unterteilt. Die meisten Fußverletzungen fanden sich in prä-EuroNCAP-Autos. Die meisten Insassen befanden sich in Fahrzeugen der unteren Mittelklasse (40 Fahrer und 9 Beifahrer) und der Mittelklasse (27 Fahrer und 7 Beifahrer). 49 der 140 Unfälle ereigneten sich auf Landes- bzw. Kreisstraßen, 26 auf Bundesstraßen und 13 auf Autobahnen. Es wurden überwiegend Frontalzusammenstöße beobachtet. Zwischen den verletzten Fußregionen fanden sich keine signifikanten Unterschiede hinsichtlich der Delta v- und EES-Werte, es ergab sich aber ein Trend zu höheren Delta v- und EES-Werten bei neueren PKW (post-EuroNCAP). Die Häufigkeit von Fußverletzungen stieg linear mit steigendem Delta v-Wert, oberhalb eines Delta v-Wertes von 55 km/h kam es nur noch in prä-EuroNCAP-Autos zu einem weiteren linearen Anstieg, während post-EuroNCAP-Fahrzeuge keinen weiteren Anstieg der Verletzungshäufigkeit zeigten. Die Fußraumintrusion zeigte keine signifikanten Unterschiede zwischen den einzelnen Fußregionen, jedoch zeigte sich in post-EuroNCAP-Fahrzeugen ein Trend zu höheren Intrusionswerten. Zwischen den einzelnen Fahrzeugklassen zeigten sich keine Unterschiede in der Fußraumintrusion. Nur 29 der 174 Frakturen und Luxationen des Fußes und des oberen Sprunggelenkes wurden in post-EuroNCAP-Fahrzeugen registiert, die überwiegende Zahl dieser Verletzungen (n=145) ereignete sich in prä-EuroNCAP-Fahrzeugen. Bei Betrachtung des AIS2008-assoziierten FCI (functional capacity index) für die Fußregion zeigte sich eine geringere Wahrscheinlichkeit einer dauerhaften Behinderung in post-EuroNCAP-Fahrzeugen bei gleichem Delta v-Wert.:1. Einleitung zur Unfallforschung in Deutschland 6 2. Fragestellung 10 3. Patientengut und Methodik 13 4. Charakteristische Frakturen und zu Grunde liegende Unfälle 23 5. Auswertung 28 5.1 Erfasste Verletzungen 28 5.2 Charakterisierung der Fahrzeuge 32 5.2.1 Fahrzeugsegment 32 5.2.2 Unfallort 33 5.2.3 Aufprallrichtung 35 5.2.4 Verletzungsverursachendes Fahrzeugteil 36 5.3 Geschwindigkeitsparameter bei den beobachteten Verletzungen 37 5.4 Fußraumintrusion bei den beobachteten Verletzungen 41 5.5 Häufigkeit von Fußverletzungen 53 6. Diskussion 54 7. Zusammenfassung 67 8. Literaturverzeichnis 69 Danksagung 95 Thesen zur Dissertation 96 / The accident research of Hanover and (from 1999 on) Dresden registered 736 leg injuries (AIS ≥ 2) from 1983 to March 2007. 174 of these injuries (23.6 %) were fractures or dislocations of foot and ankle. 149 feet of 141 front seat car occupants in 140 cars were affected. Of these 117 were drivers, 24 were front seat passengers. The mean age of occupants was 38.5 ± 16.8 years. Ankle fractures were the most frequent injury (n = 82; 80 malleolar fractures, 2 pilon fractures). 34 fractures and dislocations affected the hindfoot (5 talus and 26 calcaneal fractures, 2 subtalar dislocations and 1 subtotal amputation) , 16 to midfoot (4 navicular fractures, 5 cuboid fractures, 3 fractures of cuneiformia, 2 dislocations of chopart joint, 1 subtotal amputation, and one severe decollement) and 39 the forefoot (metatarsal fractures). Open fractures were seldom seen (2 malleolar fractures, 1 metatarsal fracture). Both feet were injured in 10 cases. 33 occupants (23.4 %) were polytaumatic had a polytrauma, 17 of them died. 81 percent of the occupants were belted. The cars were divided in pre EuroNCAP (year of manufacture 1997 and older) and post EuroNCAP cars (year of manufacture 1998 and newer). Most of the foot injuries were seen in pre EuroNCAP cars. Most of the occupants sat in compact cars (40 drivers and 9 front seat passengers) and large family cars (27 drivers and 7 co-drivers). 49 of 140 accidents occurred on country roads, 26 on main roads and 13 on motorways. The crash direction was mostly frontal. Generally were found no differences of delta v- and EES-level between the injured foot regions, but divided into pre- and post-EuroNCAP cars there was a tendency to higher delta v- and EES-levels in newer cars. The frequency of foot injuries increased linearly with increasing delta v-level; but above delta v-level of 55 km/h the linear increase only was seen in pre-EuroNCAP cars, post-EuroNCAP cars showed no further increase of injuries. The footwell intrusion showed no difference between the injured foot regions but post-EuroNCAP cars had a tendency to higher footwell intrusion. There were no differences in footwell intrusion between the car types. Only 29 of 174 fractures or dislocations of foot and ankle were seen in post-EuroNCAP cars, the predominate number of these injuries (n = 145) were noticed in pre-EuroNCAP cars. A lower probability of long-term impairment was found in post-EuroNCAP cars for equal delta v levels, using the AIS2008 associated Functional Capacity Index (FCI) for the foot region.:1. Einleitung zur Unfallforschung in Deutschland 6 2. Fragestellung 10 3. Patientengut und Methodik 13 4. Charakteristische Frakturen und zu Grunde liegende Unfälle 23 5. Auswertung 28 5.1 Erfasste Verletzungen 28 5.2 Charakterisierung der Fahrzeuge 32 5.2.1 Fahrzeugsegment 32 5.2.2 Unfallort 33 5.2.3 Aufprallrichtung 35 5.2.4 Verletzungsverursachendes Fahrzeugteil 36 5.3 Geschwindigkeitsparameter bei den beobachteten Verletzungen 37 5.4 Fußraumintrusion bei den beobachteten Verletzungen 41 5.5 Häufigkeit von Fußverletzungen 53 6. Diskussion 54 7. Zusammenfassung 67 8. Literaturverzeichnis 69 Danksagung 95 Thesen zur Dissertation 96

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