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The hook test is a widely used intraoperative method for assessing syndesmosis stability. However, there are no recommendations regarding the force required to perform this test. Furthermore, the reliability of the test is unclear. Ten experienced surgeons performed hook tests on a cadaver bone model. The applied forces were recorded in a blinded manner. In addition, standardized hook tests with defined forces (50, 80, and 100 N) were performed on 10 pairs of cadaver lower legs and the syndesmosis was sequentially destabilized. Diastasis of the syndesmosis was recorded using an optical 3D camera system. A median force of 81 N (Range: 50 N–145 N) was applied. A proportion of 82% of the tests showed a force < 100 N. The data showed good intraraterreliability and poor interraterreliability. In the standardized investigation of the hook test on the cadaver bone model, both the force and the instability of the syndesmosis had a significant influence on the syndesmosis diastasis. Nevertheless, even with maximum instability of the syndesmosis, diastasis > 2 mm could only be measured in 12 of the 19 evaluable specimens. The widely used hook test shows a high variability when performed in practice. Even in a standardized manner, the hook test cannot detect a relevant syndesmosis injury.

Plantar plate positioning has been demonstrated as biomechanically superior. However, some operators remain resentful about the morbidity of the surgical approach. To provide improved plate fixation for first tarsometatarsal joint arthrodesis with respect to the tibialis anterior tendon, a medio-plantar plate was developed. The purpose of this biomechanical study was to compare its construct stability to that of a plantar plate construct. Twelve pairs of fresh frozen human specimens were used in a matched pair test. Each pair was fixed with a 4 mm compression screw and either a plantar locking plate or a medio-plantar locking plate. A cantilever beam test was performed in dorsiflexion. Before and after cyclic loading (5000 cycles; 40 N), bending stiffness and relative movements at the joint space were monitored in a quasi-static test including optical motion tracking. Maximum load and bending moment to failure were investigated in a load-to-failure ramp test. The bending stiffness of both groups did not significantly differ before (plantar 49.9 N/mm ± 19.2; medio-plantar 53.9 N/mm ± 25.4, p = 0.43) or after (plantar 24.4 N/mm ± 9.7; medio-plantar 35.3 N/mm ± 22.0, p = 0.08) cyclic loading but decreased significantly in both groups (p < 0.01) after cyclic loading. Relative movement increased significantly during cyclic testing in both groups (p < 0.01) but did not differ significantly between the groups before (p = 0.29) or after (p = 0.16) cyclic loading. Neither load nor bending moment to failure were significantly different (plantar 225 N ± 78, 10.8 Nm; medio-plantar 210 N ± 86, 10.1 Nm, p = 0.61). Both plate constructs provided equivalent construct stability, both being well suited for Lapidus arthrodesis.

Purpose The study sought to investigate the reliability of CT-derived Hounsfield unit (HU) measurements and ascertain the correlation between HU with qCT-derived bone mineral density (BMD) in cases of traumatic thoracolumbar fracture, based on native CT scans. Methods This study is a retrospective cross-sectional analysis of data sets from patients, which received native CT scans and bone mineral density measurements (qCT) of the same vertebral body. Two different CT scanner models were used. The inter-rater reliability of four rater, which measured HU in native CT scans, was calculated using intra class correlation coefficient for absolute agreement (ICC(3, 1)). For the correlation between HU and qCT values, respectively the prediction of qCT based on HU, linear regression was used. Bland-Altman plots were used for visual comparison of predicted and measured qCT values. Results In total 305 datasets were analyzed. CT scanner model were found to have no significant impact on HU (p=0.125). The inter-rater reliability for HU measurements from native CT scans was ICC(3, 1)=0.932 (CI95: 0.919 – 0.943, p Conclusions HU measurement shows very high inter-rater reliability. The HU values correlate closely with qCT BMD values. In summary, it seems that HU measurement is a suitable tool to readily and accurately assess bone quality without further scans or effort in cases of thoracolumbar spinal trauma.

Background Anxiety in combination with osteoporotic vertebral compression fractures (OVCFs) of the spine remains understudied. The purpose of this study was to analyze whetheranxiety has an impact on the short-term functional outcome of patients with an OVCF. Furthermore, a direct impact of the fracture on the patient’s anxiety during hospitalization should be recognized. Methods A prospective multicentric study in a German-speaking area was performed. All inpatients with an OVCF of the thoracolumbar spine from 2017 to 2020 were included. Trauma mechanism, analgetic medication, anti-osteoporotic therapy, timed-up-and-go test (TuG), mobility, Barthel index, Oswestry-Disability Index (ODI) and EQ5D-5L were documented. For statistical analysis, the U test, chi-square independence test, Spearman correlation, General Linear Model for repeated measures, Bonferroni analysis and Wilcoxon test were used. The item anxiety/depression of the EQ5D-5L was analyzed to describe the patients’ anxiousness. Results Data from 518 patients from 17 different hospitals were evaluated. Fracture severity showed a significant correlation (r=0.087, p=0.0496) with anxiety. During the hospital stay, pain medication (pConclusions Higher anxiety is associated with lower functional outcome after OVCF. The item anxiety/depression of the EQ5D-5L provides an easily accessible, quick and simple tool that can be used to screen for poor outcomes and may also offer the opportunity for a specific anxiety intervention.

Zusammenfassung Einleitung Bei der Behandlung von Verletzungen der oberen Halswirbelsäule hat das semikonservative Verfahren des Halofixateurs heute eine untergeordnete Rolle. Ältere Studien aus den 2000er-Jahren zeigten unbefriedigende Durchbauungsraten sowie hohe Komplikationsraten. Jedoch resultiert aufgrund aktueller Daten zur Therapieeffektivität derzeit eine kontroverse Literaturlage. Ziel der Arbeit ist es, eigene Erfahrungen und Ergebnisse der Behandlung der aktuellen Literatur gegenüberzustellen und einen klärenden Beitrag zur Rolle des Halofixateurs zu leisten. Material und Methoden In einer monozentrischen retrospektiven Kohortenstudie wurden Patienten mit instabilen Verletzungen der axialen Halswirbelsäule untersucht, die im Halofixateur ausbehandelt werden sollten. Anhand der elektronischen Krankenakte wurden individuelle Variablen (Geschlecht, Alter, Nebenerkrankungen, Charlson Comorbidity Index) und Therapiekennwerte (Dauer der Behandlung, Konsolidierungszustand, Komplikationen) erfasst. Die Verletzungen wurden aufgrund der CT-Daten zum Unfallzeitpunkt und zum Behandlungsende anhand gängiger Klassifikationssysteme eingeteilt und hinsichtlich der Konsolidierungsrate beurteilt. Mögliche Einflussfaktoren auf die knöcherne Konsolidierung sowie Komplikationen wurden statistisch analysiert. Ergebnisse Insgesamt 54 Patienten/-innen entsprachen den Einschlusskriterien. Die Behandlungsdauer lag im Median bei 83 Tagen. Die häufigsten Verletzungen waren die isolierte Atlasfraktur Typ III (7; 13%) und die isolierte Densfraktur Typ III (24; 44%). Eine knöcherne Konsolidierung konnte in 34 Fällen (63%) und eine straffe Pseudarthrose in 13 Fällen (24%) nachgewiesen werden. In 6 Fällen (11%) wurde sekundär eine operative Stabilisierung durchgeführt. Isolierte Atlasfrakturen Typ III und Densfrakturen Typ III wiesen mit 86% bzw. 92% sehr hohe Konsolidierungsraten auf. In den Subgruppen von Patienten/-innen über 65 Jahren bzw. mit einem CCI ≥ 4 fanden sich häufiger instabile Pseudarthrosen. Als Komplikationen traten Pin-Infektionen (6%), Pin-Dislokationen (9%) und Druckulzerationen durch die Haloweste (6%) auf. Kardiopulmonale Komplikationen traten nicht auf. Kein Patient verstarb. Diskussion Es zeigten sich für Atlasfrakturen Typ III sowie Densfrakturen Typ III gute Raten für die knöcherne Konsolidierung, die mit den Angaben in der Literatur korrelieren. Densfrakturen Typ II (isoliert und kombiniert) und Atlasfrakturen Typ III in Kombination mit Densfrakturen zeigten ein schlechteres radiologisches Outcome, das auch im Vergleich zur Literatur unbefriedigend ist. Die Raten für verfahrensspezifische Komplikationen waren relativ niedrig. Insbesondere Arbeiten aus den letzten Jahren konnten sehr gute Raten für die knöcherne Konsolidierung und niedrige Komplikationsraten für die Behandlung von Atlas- und /oder Densfrakturen mit dem Halofixateur nachweisen, die durch unsere Ergebnisse bestätigt werden. Im Kontrast dazu wird allerdings über eine deutlich höhere kardiale/respiratorische Komplikationsrate berichtet, als sie im eigenen Patientenkollektiv auftrat.

In the treatment of ankle fractures, complications such as wound healing problems following open reduction and internal fixation are a major problem. An innovative alternative to this procedure offers a more minimally invasive nail stabilization. The purpose of this biomechanical study was to clarify whether this method was biomechanically comparable to the established method. First, the stability (range of motion, diastasis) and rotational stiffness of the native upper ankle were evaluated in eight pairs of native geriatric specimens. Subsequently, an unstable ankle fracture was created and fixed with a locking plate or a nail in a pairwise manner. The ankles showed significantly less stability and rotational stiffness properties after nail and plate fixations than the corresponding native ankles (p < 0.001 for all parameters). When comparing the two methods, both showed no differences in their range of motion (p = 0.694) and diastasis (p = 0.166). The nail also presented significantly greater rotational stiffness compared to the plate (p = 0.001). However, both fixations remained behind the native stability and rotational stiffness. Due to the comparable biomechanical properties of the nail and plate fixations, an early weight-bearing following nail fixation should be assessed on a case-by-case basis considering the severity of fractures.

Background: The correction of malposition according to vertebral fractures is difficult because the alignment at the time before the fracture is unclear. Therefore, we investigate whether the spinal alignment can be determined by the spino-pelvic parameters. Methods: Pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), adjacent endplate angles (EPA), age, sex, body weight, body size, BMI, and age were used to predict mono- and bisegmental EPA (mEPA, bEPA) in the supine position using linear regression models. This study was approved by the Ethics Committee of the Medical Association of Saxony-Anhalt Germany on 20 August 2020, under number 46/20. Results: Using data from 287 patients, the prediction showed R2 from 0.092 up to 0.972. The adjacent cranial and caudal EPA showed by far the most frequently significance in the prediction of all parameters used. Anthropometric and spino-pelvic parameters showed sparse impact, which was frequently in the lower lumbar regions. On average, a very good prediction was found. For two mEPA (L3/4 R2 = 0.914, L4/5 R2 = 0.953) and two bEPA (L3 R2 = 0.899, L4 R2 = 0.972), the R2 was >0.8. However, the predicted EPA differed for individual patients, even in these very effective prediction models—roughly around ±10° as compared to the measured EPA. Conclusions: In general, the prediction showed good to perfect results. In the supine position, the spinopelvic and anthropometric parameters show sparse impact on the prediction of mEPA or bEPA.

Zusammenfassung Hintergrund Ziel der Operation von Wirbelsäulenverletzungen ist eine stabile Ausheilung in physiologischer Stellung. Für offene und perkutane Operationen stehen unterschiedliche Techniken zur Verfügung. Fragestellung Das Ausmaß der offenen Reposition und das Retentionspotenzial der Techniken nach AOSpine (AT) und nach Kluger (KT) sollen verglichen werden. Der Einfluss von Frakturmorphologie, Alter, Geschlecht und Knochenqualität auf Reposition und Retention werden untersucht. Material und Methoden In dieser monozentrischen retrospektiven Kohortenstudie wurden Daten von Patienten mit traumatischen thorakolumbalen und lumbalen Frakturen untersucht, welche entweder mit AT oder KT reponiert wurden. Mittels bisegmentalen Grund-Deckplatten-Winkels (bGDW) wurde die Stellung des verletzten Wirbelsäulenabschnitts beschrieben. Normalwerte für die bGDW wurden anhand von Literaturdaten angenommen. Die Veränderung des bGDW im zeitlichen Verlauf wurde unter Einbeziehung der Knochenqualität in Hounsfield Units (HU), der Verletzungsschwere nach AOSpine und des Patientenalters und -geschlechts analysiert. Ergebnisse Es wurden 151 Datensätze ausgewertet. Beide Methoden reponieren vom Umfang nicht unterschiedlich (AT 10 ± 6°, KT 11 ± 8°; p = 0,786). Im Follow-up trat ein Korrekturverlust von −5 ± 4° auf. Die Technik (p = 0,998) hatte keinen Einfluss darauf. Die Frakturmorphologie zeigte einen knapp signifikanten Einfluss (p = 0,043). Niedrige HU korrelierten mit geringerem Repositionsumfang (r = 0,241, p p p Diskussion Die Techniken sind gleichwertig bezüglich der Repositions- und Retentionseigenschaften. Der hohe Anteil von Patienten mit HU

Heat stress is a major environmental stress type that can limit plant growth and development. To survive sudden temperature increases, plants utilize the heat shock response, an ancient signaling pathway. Initial results had suggested a role for brassinosteroids (BRs) in this response. Brassinosteroids are growth-promoting steroid hormones whose activity is mediated by transcription factors of the BES1/BZR1 subfamily. Here, we provide evidence that BES1 can contribute to heat stress signaling. In response to heat, BES1 is activated even in the absence of BRs and directly binds to heat shock elements (HSEs), known binding sites of heat shock transcription factors (HSFs). HSFs of the HSFA1 type can interact with BES1 and facilitate its activity in HSE binding. These findings lead us to propose an extended model of the heat stress response in plants, in which the recruitment of BES1 is a means of heat stress signaling cross-talk with a central growth regulatory pathway.

The goal of surgery for spinal injuries is fracture reduction, fixation and stable healing in a physiological position. Several open and minimally invasive surgical techniques are available.The extent of open reduction and the fixation potential achieved by the AOSpine (AT) and Kluger (KT) techniques were compared. The influence of fracture morphology, age, sex, and bone quality on fracture reduction and secure fixation was investigated.In this monocentric retrospective cohort study data of patients with traumatic thoracolumbar and lumbar fractures treated by AT or KT were analyzed. The bisegmental kyphotic angle (bGDW) of each injured spinal segment was determined. Normal bGDW values were extrapolated from the literature. The change of bGDW over time was analyzed under consideration of the bone quality in Hounsfield units (HU), injury severity according to the AOSpine classification, gender and age of patients.A total of 151 data sets were evaluated. The AT and KT methods achieved a similar extent of reduction (AT 10 ± 6°, KT 11 ± 8°; p = 0.786). In follow-up a mean reduction loss of -5 ± 4° was seen. The technique had no influence on this (p = 0.998). The fracture morphology just managed to achieve a significant influence (p = 0.043). Low HU correlated significantly but weakly with lower extent of reduction (r = 0.241, p 0.003) and greater reduction loss (r = 0.272, p 0.001). In the age group 50-65 years 21% of men and 43% of women had bone quality of 110 HU. Age and HU were significantly correlated (r = -0.701, p 0.001).The AT and KT are equivalent in terms of reduction and secure fixation properties. The high proportion of male and female patients with HU 110 in the age group under 65 years and the influence on reduction and secure fixation emphasize the need for preoperative bone densitometry.HINTERGRUND: Ziel der Operation von Wirbelsäulenverletzungen ist eine stabile Ausheilung in physiologischer Stellung. Für offene und perkutane Operationen stehen unterschiedliche Techniken zur Verfügung.Das Ausmaß der offenen Reposition und das Retentionspotenzial der Techniken nach AOSpine (AT) und nach Kluger (KT) sollen verglichen werden. Der Einfluss von Frakturmorphologie, Alter, Geschlecht und Knochenqualität auf Reposition und Retention werden untersucht.In dieser monozentrischen retrospektiven Kohortenstudie wurden Daten von Patienten mit traumatischen thorakolumbalen und lumbalen Frakturen untersucht, welche entweder mit AT oder KT reponiert wurden. Mittels bisegmentalen Grund-Deckplatten-Winkels (bGDW) wurde die Stellung des verletzten Wirbelsäulenabschnitts beschrieben. Normalwerte für die bGDW wurden anhand von Literaturdaten angenommen. Die Veränderung des bGDW im zeitlichen Verlauf wurde unter Einbeziehung der Knochenqualität in Hounsfield Units (HU), der Verletzungsschwere nach AOSpine und des Patientenalters und -geschlechts analysiert.Es wurden 151 Datensätze ausgewertet. Beide Methoden reponieren vom Umfang nicht unterschiedlich (AT 10 ± 6°, KT 11 ± 8°; p = 0,786). Im Follow-up trat ein Korrekturverlust von −5 ± 4° auf. Die Technik (p = 0,998) hatte keinen Einfluss darauf. Die Frakturmorphologie zeigte einen knapp signifikanten Einfluss (p = 0,043). Niedrige HU korrelierten mit geringerem Repositionsumfang (r = 0,241, p 0,003) und größerem Korrekturverlust (r = 0,272, p 0,001) signifikant, aber schwach. In der Altersgruppe 50 bis 65 Jahre wiesen 21 % der Männer und 43 % der Frauen eine Knochenqualität von HU 110 auf. Alter und HU korrelieren signifikant (r = −0,701, p 0,001).Die Techniken sind gleichwertig bezüglich der Repositions- und Retentionseigenschaften. Der hohe Anteil von Patienten mit HU 110 in der Gruppe unter 65 Jahren bei Frauen und Männern und der Einfluss auf Reposition und Retention weisen auf die Notwendigkeit einer präoperativen Knochendichtemessung hin.

PurposeThe aim of this study was to evaluate the reliability of Hounsfield units (HU) for bone density measurement in spinal trauma. HU have already been demonstrated to be reliable for this purpose in degenerative spine disease.Methods This study is a retrospective cross-sectional analysis considering CT scanner model, slice thickness and HU in native and contrast CT scans. Linear regression, bivariate correlation and ROC analyses were performed to analyze the relationship between qCT values and HU. The inter-rater reliability of HU measurements was assessed using the intra-class correlation coefficient.Results344 patient datasets were analyzed. CT scanner model and slice thickness were found to have no significant impact on HU. The inter-rater reliability for HU measurements from native CT scans was ICC(3, 1)=0.932 (CI95: 0.919 – 0.943, pwithout CM+5 can be used to predict qCT values from native CT scan HU. ROC analysis revealed maximum sensitivity and specificity of 0.91 and 0.93, respectively, with a cut-off value of 93 HU to predict osteoporosis.For contrast CT scans we determined an ICC(3,1) of 0.889 (CI95: 0.801 – 0.948, pwith CM-4. The maximum sensitivity and specificity calculated using HU in the presence of contrast medium were 0.83 and 0.89 with cut-off of values of 122 and 125 HU, respectively, depending on the observer.ConclusionsHU are reliable for measurement of bone quality in spinal trauma, especially in native CT scans. HU measurements from contrast CT scans should be used more cautiously for bone quality estimation.

Purpose Posterior multilevel fixation of traumatic instability in ankylosing spinal disease (ASD) can be performed by open surgery (OS) or minimally invasive surgery (MIS). We investigated whether both methods differ based on the reduction results and perioperative parameters. Methods In this retrospective cohort study, OS and MIS groups were investigated. The bisegmental Cobb angles and dislocation angles were measured using pre- and postoperative CT images, and the initial malalignment and achieved reduction were calculated. Cut-seam time, calculated blood loss, transfusion number, fluoroscopy time, pedicle screw placement accuracy, duration of ICU stay, in-patient stay, and complications (bleeding, postoperative thrombosis and embolism, and postoperative mortality) were recorded. Results Seventy-five ASD patients with spine fractures (Ø 75 ± 11 years, male: 52, female: 23) (MIS: 48; OS: 27) were included in this study. The extent of reduction did not differ in the OS and MIS groups (p = 0.465; MIS:− 1 ± 3°, OS:−2 ± 6°). The residual postoperative malalignment angle was not significantly different (p = 0.283). Seventy-eight of the implanted screws (11%) showed malpositioning. No difference was found between OS and MIS (MIS, 37 [7%]; OS, 41 [16%]; p = 0.095). MIS was associated with less blood loss (OS: 1.28 ± 0.78 l, MIS: 0.71 ± 0.57 l, p = 0.001), cut-seam time (MIS: 98 ± 44 min, OS: 166 ± 69 min, p p = 0.02) than OS. Conclusion OS and MIS show equally limited performance in terms of the fracture reduction achieved. The MIS technique was superior to OS based on the perioperative outcome. Therefore, MIS should be preferred over OS for unstable spinal injuries, excluding C-type fractures, in ASD patients without neurological impairment.

Minimally invasive fixation of pelvic fragility fractures is recommended to reduce pain and allow early mobilization. The purpose of this study was to evaluate the outcome of two different stabilization techniques in bilateral fragility fractures of the sacrum (BFFS).A non-randomized, prospective study was carried out in a level 1 trauma centre. BFFS in 61 patients (mean age 80 years (SD 10); four male, 57 female) were treated surgically with bisegmental transsacral stablization (BTS; n = 41) versus spinopelvic fixation (SP; n = 20). Postoperative full weightbearing was allowed. The outcome was evaluated at two timepoints: discharge from inpatient treatment (TP1; Fitbit tracking, Zebris stance analysis), and ≥ six months (TP2; Fitbit tracking, Zebris analysis, based on modified Oswestry Disability Index (ODI), Majeed Score (MS), and the 12-Item Short Form Survey 12 (SF-12). Fracture healing was assessed by CT. The primary outcome parameter of functional recovery was the per-day step count; the secondary parameter was the subjective outcome assessed by questionnaires.Overall, no baseline differences were observed between the BTS and SP cohorts. In total, 58 (BTS = 19; SP = 39) and 37 patients (BTS = 14; SP = 23) could be recruited at TP1 and TP2, respectively. Mean steps per day at TP1 were median 308 (248 to 434) in the BTS group and 254 (196 to 446) in the SP group. At TP2, median steps per day were 3,759 (2,551 to 3,926) in the BTS group and 3,191 (2,872 to 3,679) in the SP group, each with no significant difference. A significant improvement was observed in each group (p0.001) between timepoints. BTS patients obtained better results than SP patients in ODI (p0.030), MS (p = 0.007), and SF-12 physical status (p = 0.006). In all cases, CT showed sufficient fracture healing of the posterior ring.Both groups showed significant outcome improvement and sufficient fracture healing. Both techniques can be recommended for BFFS, although BTS was superior with respect to subjective outcome. Step-count tracking represents a reliable method to evaluate the mobility level. Cite this article

A retrospective, longitudinal cohort study.The purpose of this study was to examine whether Hounsfield units (HUs), as an alternative bone mineral density measurement to dual-energy X-ray absorptiometry and quantitative computed tomography, which lead to additional radiation exposure for patients, has an effect on the maintenance of reduction in bisegmental Cobb angle (CA) and cage subsidence in patients who receive bisegmental spine stabilization after traumatic thoracolumbar spine fractures.A total of 81 patients with a mean follow-up of 12 months were analyzed. CAs and cage subsidence were measured intraoperatively and at follow-up. HU was measured, and patients were subsequently assigned based on HU to three HU subgroups (group 1: HU 110 [poor bone quality (BQ)]; group 2: HU 180-110 [diminished BQ]; group 3: HU 180 [good BQ]).Following anterior stabilization, loss of reduction and cage subsidence differed between patients with poor and diminished BQ but not significantly, and both groups showed significantly more loss of reduction and cage subsidence than patients with good BQ.BQ, estimated with HU, had significant effects on cage subsidence and loss of reduction. We recommend measuring HU before surgery and applying additional treatment strategies, such as polymethylmethacrylate augmentation of endplates or anterior plates, for patients with HU 180. These slides can be retrieved under Electronic Supplementary Material.

Muscle architecture parameters change when the muscle changes in length. This has multiple effects on the function of the muscle, e.g. on force production and on contraction velocity. Here we present a versatile geometrical model that predicts changes in muscle architecture as a consequence of length changes of the muscle on the basis of the known architecture at a given muscle length. The model accounts for small changes in aponeuroses’ dimensions relative to changes in fascicle length and keeps muscle volume constant. We evaluate the model on the rabbit soleus muscle by comparing model predictions of fascicle lengths and pennation angles with experimental data. For this, we determined the internal architecture of the soleus muscle at different muscle belly lengths (67.8 mm at 35° ankle angle and 59.3 mm at 80° ankle angle). The long and the short soleus muscle exhibited mean fascicle lengths and pennation angles of 20.8 ± 1.3 mm, 4 ± 2° and 13.5 ± 1 mm, 10 ± 4°, respectively. The model predicted reasonable mean fascicle lengths and pennation angles for the long and short soleus that differed only by 1 mm and 1° from the measured data, respectively. Differences between predicted and measured distributions seem to stem from interindividual variability in muscle architecture. Even if the proposed approach has been used for the soleus muscle, which is relatively simple in architecture, it is not restricted to homogeneous unipennate architectures.

We report a difficult healing process after a femoral shaft fracture in childhood. We present surgical correction options of femoral shortening due to pseudarthrosis after elastic stable intramedullary nailing. First, we tried to establish distraction using an external fixator, followed by plate osteosynthesis. After material failure of plate osteosynthesis, we treated the refracture with intramedullary nailing, after which bone healing occurred.

Background The Sorensen test is commonly used to assess back muscle endurance capacity. However, the clinical value of this test, requiring compensation of the entire upper body mass, is limited if pain occurs. Therefore, a test variant using only portions of upper body mass could be an alternative. Objective This study aimed to determine fatigue characteristics in lumbar muscles during a modified Sorensen test utilizing only 50% of the upper body mass and asked if localization-related effects of surface electrodes in the assessment of lumbar muscle fatigue should be considered. Methods Thirty-two young (20-29 years) symptom-free men were enrolled and asked to maintain only 50% upper body mass for 10 minutes. Fatigue characteristics were bilaterally derived from four different lumbar levels using Surface EMG. Side-specific and SEMG parameter-independent repeated measures (four lumbar levels, nine time points) analyses of variance were conducted. Results All participants were able to complete the test. Over time, a spatial effect of fatigue-related amplitude alterations at the respective segments could be observed. Conclusions By using this modified Sorensen test, muscular fatigue can be evoked. Electrophysiological assessment of lumbar fatigue should consider spatial differences.

Safety shoe designs are primarily based on safety requirements. But all-day comfort should not be luxury: Heel strike associated impact loads on joints need to be compensated by active muscular effort and safety shoes should support this protective function of muscle activation. In 10 healthy men, 12 trunk and leg muscles were analyzed with surface electromyography. Subjects walked on a walkway while wearing different safety shoes with the test shoes being equipped with exchangeable cushioning heel inserts according to individuals' body weight. While wearing the optimally cushioned shoes the cumulative muscle activity per distance travelled dropped clearly compared to the regular safety shoes, demonstrating reduced muscular effort. Also, the heel strike associated amplitude peak of back muscles occurred earlier within the stride while wearing the test shoes. Thus weight-balanced cushioning heel inserts in safety shoes proved able to reduce muscle strain, logically delaying muscular fatigue and extending muscular joint protection. Relevance to industry Adjustable heel inserts in safety shoes are suited to improve the health status of employees by reducing muscular effort so that active joint protection can be prolonged.

Wahrend des Tragens von Sicherheitsschuhen lasst sich mit zunehmender Tragedauer ein deutlicher Optimierungseffekt im muskularen Aufwand bei Verwendung einer gewichtsangepassten Fersendampfung nachweisen, der ohne Verwendung dieser Dampfung nicht nur nicht, sondern sogar in umgekehrter Richtung sichtbar wird: ohne Dampfung erhoht sich der muskulare Aufwand mit langerer Tragedauer. Eine gewichtsangepasste Fersendampfung kann den Arbeitnehmer somit vor unnotiger Mehrbelastung der Muskulatur und daraus resultierenden gesundheitlichen Folgen bewahren.

In the last decade, diffusion tensor imaging (DTI) has been used increasingly to investigate three-dimensional (3D) muscle architectures. So far there is no study that has proved the validity of this method to determine fascicle lengths and pennation angles within a whole muscle. To verify the DTI method, fascicle lengths of m. soleus as well as their pennation angles have been measured using two different methods. First, the 3D muscle architecture was analyzed in vivo applying the DTI method with subsequent deterministic fiber tractography. In a second step, the muscle architecture of the same muscle was analyzed using a standard manual digitization system (MicroScribe MLX). Comparing both methods, we found differences for the median pennation angles (P

There exists several numerical approaches to describe the active contractile behaviour of skeletal muscles. These models range from simple one-dimensional to more advanced three-dimensional ones; especially, three-dimensional models take up the cause of describing complex contraction modes in a realistic way. However, the validation of such concepts is challenging, as the combination of geometry, material and force characteristics is so far not available from the same muscle. To this end, we present in this study a comprehensive data set of the rabbit soleus muscle consisting of the muscles' characteristic force responses (active and passive), its three-dimensional shape during isometric, isotonic and isokinetic contraction experiments including the spatial arrangement of muscle tissue and aponeurosis-tendon complex, and the fascicle orientation throughout the whole muscle at its optimal length. In this way, an extensive data set is available giving insight into the three-dimensional geometry of the rabbit soleus muscle and, further, allowing to validate three-dimensional numerical models.

OBJECTIVE The aim of the study was to analyze the microbial colonization rate as well as the spectrum and number of microorganisms in relation to the indwelling time of pancreatic stents. METHODS Forty pancreatic stents were prepared according to a standardized protocol and subsequently sonicated to optimize bacterial release from the biofilm on the stents. RESULTS Two hundred forty-six microorganisms were identified. Thirty-nine of 40 stents were colonized with microorganisms. Aerobic gram-positive microorganisms (106/246 [43%]) accounted for the greatest proportion. The predominant microorganisms were Streptococcus species (46/246 [19%]), which were isolated from 27 (68%) of 40 stents. Stents with a short indwelling time (3-13 days) were mainly colonized with aerobic gram-positive bacteria (82%) and Candida species (63%). In contrast, anaerobes (P < 0.01, 69% vs 18%) and aerobic gram-negative microorganisms (P < 0.01, 93% vs 45%) such as Enterobacteriaceae (P < 0.01, 86% vs 27%) were significantly more present on stents with a long indwelling time (29-93 days), compared with stents with a short indwelling time. CONCLUSIONS Microbial analysis of pancreatic duct stents revealed a very high colonization rate. Furthermore, the spectrum and number of microorganisms altered with the indwelling time of the stent. However, clinical relevance of our findings remains unclear.

To judge a person’s maximum trunk extension performance as either age-appropriate or deconditioned is challenging. The current study aimed at determining age and anthropometrically adjusted maximum voluntary contraction (MVC) of back extensors considering the number and recovery time between trials. Thirty-one younger (20–30 years) and 33 older (50–60 years) healthy males performed five repetitions of maximal isometric trunk extensions in an upright standing position with randomized recovery times ranging between one to five minutes at one minute intervals. Torque values were normalized according to the individual’s upper body mass resulting in upper body torque ratios (UBTR). To evaluate the impact of age, recovery time, and fatigue on UBTR we applied a linear mixed-effects model. Based on surface EMG data muscular fatigue could be excluded for both groups. For all MVC trials, UBTR levels differed significantly between age groups (range of mean values: younger: 2.26–2.28, older: 1.78–1.87, effect size: 1.00) but were independent from recovery time. However, the older males tended to exert higher UBTR values after shorter recovery periods. The study provides normative values of anthropometrically and age-group adjusted maximum back extensor forces. For the investigated groups, only two MVC trials with a recovery time of about one minute seem appropriate.

Exact electrode positioning is vital for obtaining reliable results in Surface EMG. This study aimed at systematically assessing the influence of defined electrode shifts on measured Surface EMG amplitudes of trunk muscles in a group of 15 middle aged healthy male subjects. The following leftsided muscles were investigated: rectus abdominis muscle, internal and external oblique abdominal muscles, lumbar multifidus muscle, and longissimus muscle. In addition to the recommended electrode positions, extra electrodes were placed parallel to these and along muscle fiber direction. Measurements were performed under isometric conditions in upright body position. Gradually changing, but defined loads were applied considering subject's upper body weight. For the abdominal muscles amplitude differences varied considerably depending on load level, magnitude, and direction. For both back muscles amplitudes dropped consistently but rather little for parallel electrode displacements. However, for the longissimus muscle a caudal electrode shift resulted in an amplitude increase of similar extent and independent from load level. Influence of electrode position variations can be proven for all trunk muscles but are more evident in abdominal than back muscles. Those muscle-specific effects confirm the necessity for an exact definition of electrode positioning to allow comparisons between individual subjects, groups of subjects, and studies.