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In the present research, a numerical modeling approach of the initial stage of consolidation during spark plasma sintering on the microscopic scale is presented. The solution of a fully coupled thermo-electro-mechanical problem also accounting for grain boundary and surface diffusion is found by using a staggered way. The finite-element method is applied for solving the thermo-electro-mechanical problem while the finite-difference method is applied for the diffusion problem. A Lagrange-based non-linear formulation is used to deal with the detailed description of plastic and creep strain accumulation. The numerical model is developed for simulating the structural evolution of the involved particles during sintering of powder compacts taking into account both the free surface diffusion of the particles and the grain boundary diffusion at interparticle contact areas. The numerical results obtained by using the two-particle model—as a representative volume element of the powder—are compared with experimental results for the densification of a copper powder compact. The numerical and experimental results are in excellent agreement.

Nonunion of the radial neck poses an enormous challenge for treating surgeons. It is a very rare complication of the radial neck with limited experiences. In this current major study, the authors report of their own experiences concerning this problem. 11 patients with severe displaced radial neck fracture Metaizeau type IV with elbow dislocation and 2 ongoing fractures. 9 fractures had to be treated with open reduction, six with intramedullary nailing, two with K-wires and one with periosteal suture fixation. In two children, aged 4 and 5, the fracture was not diagnosed initially. The patients showed a successful reduction intraoperatively. All patients developed nonunion of the radial neck. 9 out of 11 children presented with pain and 5 out of 11 with valgus deformity. All children underwent surgical management of the complications. 3 children received a debridement of the elbow joint with resection of the fragmented radial head. 7 cases needed a following reduction, spongiosa-plasty and periosteal flap reconstruction and plate osteosynthesis. One patient received radial intramedullary pinning. All nonunions showed reunion. All patients with obtained radial head showed significant improvement concerning complaints and range of motion. Only one child showed a slight deterioration in range of motion. Children with resected radial head showed good range of motion but complaints and instability in loaded joint needing further surgical treatment. Treatment of radial neck nonunion in children should not be delayed until pain, deformity and limited function occurs because this goes along with severe transition of the radial head right up to bone atrophy.

Due to their outstanding mechanical properties, carbon nanotubes (CNTs) are very promising materials for further applications in the field of lightweight construction. Carbon nanotube fibers, whose structure consists of a multitude of load-bearing carbon nanotube bundles interconnected by threads, are an excellent possibility to utilize these properties as engineering material. In the present research, a new method for the prediction of the mechanical properties of carbon nanotube bundles is presented. Within this, the complex structure is transformed into a simplified model based on suitable assumptions. Several parameters of the bundle are taken into account such as different types of nanotubes and various nanotube lengths. The model is applied to different configurations of carbon nanotube bundles by using a molecular mechanics approach. The interactions between the nanotubes are investigated by analyzing the Lennard–Jones potential in a virtual tensile loading test. For different configurations, the resulting forces and stresses are obtained. The results give a clear insight into the influencing parameters and demonstrate their effect on the mechanical behavior. In conclusion, the present approach is an excellent method to analyze the mechanical behavior of CNT bundles.

Purpose The aim of the study was to evaluate predictable parameters with the highest sensitivity used in the diagnosis of children septic shoulder arthritis. Methods All children treated in our paediatric orthopaedic hospital between 2000 and 2017 with intraoperative verified septic arthritis of the shoulder were included in this retrospective study. Diagnostic procedures e.g. ultrasound, MRI, radiograph or blood samples as well as typical clinical symptoms were evaluated as predictable parameters for septic shoulder arthritis in paediatric patients. Descriptive statistics as well as sensitivity analysis were performed. Results In all, 25 children, 20 boys and five girls, aged from eight days to 15 years, were included for further statistical analysis. All parameters included were tested for sensitivity with binomial confidence intervals (Cis) of 95%. Predictive parameters with highest sensitivity were pseudo paralysis (100%, CI 0.86 to 1.00) and C-reactive protein (CRP) (96%, CI 0.79 to 0.99) superior to temperature (52%, CI 0.3 to 0.73), white blood count (11%, CI 0.01 to 0.34), radiograph (21%, CI 0.04 to 0.50), ultrasound (71%, CI 0.47 to 0.88) or MRI (100%, CI 0.78 to 1.00). Conclusion The diagnosis of a septic arthritis of the shoulder in children can be challenging for the clinician and especially for the resident doctor. Clinical symptoms such as pseudo paralysis and increased CRP level must be considered as predictive markers not to delay further diagnostics and treatment. Level of Evidence IV

The objective of the paper is to analyse the role of the labrum with particular attention to its morphological changes in unstable dysplastic hips during treatment. Between January 2013 and December 2015, data were collected on 86 unstable, dysplastic hips, which were divided into type D (n = 13), type III (n = 49) and type IV (n = 24). The labrum was evaluated with ultrasound examination (US) for echogenicity and dimensions with inter-/intra-observer tests comparing the US images at diagnosis and at the end of treatment. Statistical analysis was performed. At the end of treatment of unstable, dysplastic hips, the labrum was more echogenic with a frequency of 97% and was larger with a frequency of 96%. The labrum has an active stabilizing role in unstable dysplastic hips and it undergoes a statistically significant increase of echogenicity and dimensions after treatment.Cite this article: EFORT Open Rev 2019;4 DOI: 10.1302/2058-5241.4.180053

Die Huftdysplasie ist eine der haufigsten Erkrankungen in der Kinderorthopadie. Die Behandlung hat sich mit Einfuhrung der Sonographie wesentlich verandert. Die Diagnose und die Therapie haben sich in das fruhe Sauglingsalter vorverlagert. Damit befinden wir uns seit mehr als 20 Jahren in einer Zeit, in der die Huftdysplasiebehandlung durch die Sonographie bestimmt wird. Eine grose Menge an neuen Publikationen ist hinzugekommen. Bildgebende Verfahren wie die Magnetresonanztomographie zeigen neue Aspekte auf. Mit der Arthroskopie ist ein neues operatives Verfahren hinzugekommen. Dennoch spielen viele – vor allem in der operativen Therapie – bewahrte Techniken weiterhin eine grose Rolle. In dieser Arbeit werden neue und bewahrte diagnostische Verfahren sowie konservative und operative therapeutische Masnahmen dargestellt. Dabei muss berucksichtigt werden, dass bei der Vielzahl der Literatur nicht alle Aspekte im Detail beleuchtet werden konnen. Die Arbeit orientiert sich vor allem an der durch ein Huftscreening im deutschsprachigen Raum etablierten Behandlung. Aber internationale diagnostische und therapeutische Sichtweisen sollen einbezogen werden.

Introduction: It is often difficult to clinically and radiologically diagnose intra-articular osteoid osteomas and osteoid osteomas of the hip joint. Treatment can also be difficult due to complex locational relationships. CT-guided radiofrequency ablation is currently the standard form of treatment. In this paper we report on a minimally-invasive concept for treating osteoid osteomas near the hip joint in children and adolescents which does not involve using computed tomography. Material and method: 10 patients with an average age of 12.1 years underwent treatment for osteoid osteomas in the hip joint region. The diagnosis was made using a contrast-enhanced MRI. The osteoid osteomas were marked percutaneously using x-ray and MRI guidance. MRI-guided drilling/curettage was performed in 4 cases and arthroscopic resection in 6 cases. Results: All lesions were successfully treated using the MRI-guided method. All patients were free of pain after the treatment. There was no instance of recurrence during the follow-up period, which averaged 10 months. The effective dose for marking the lesion was between 0.0186 mSv and 0.342 mSV (mean 0.084 mSV). Conclusions: Our MRI diagnostics protocol, the MRI-guided drilling and the minimally invasive hip arthroscopy represent an alternative to CT-guided radiofrequency ablation in the treatment of osteoid osteomas. Radiation exposure can thereby be significantly reduced. Hip arthroscopy can also be used to treat secondary pathologies such as femoroacetabular impingement.

Ulnar humeral condyle fractures are rare paediatric elbow fractures, classified as Salter-Harris IV paediatric elbow injuries. Due to constant radiological changes in the elbow with varying manifestation of ossification centres as well as late ossification of the trochlea, diagnosis of these injuries is challenging. To avoid long-term complications, the treating surgeon should be familiar with the rare injury picture, diagnostics and adequate therapeutic measures.The present retrospective study includes data on all paediatric cases from 2002 to 2019 with primary or secondary treatment at a paediatric traumatology centre for ulnar condyle fracture with a minimum follow-up of 12 months. Range of motion, joint stability under valgus and varus stress as well as axial ratios of the injured and uninjured side were evaluated in a clinical follow-up examination. The Mayo Elbow Performance Score was used to objectify functional results.20 children, average age 8.6 years (4 - 13) and average follow-up time 25 months, were included. Radiological evaluation based on Jakob and Fowles classification revealed a type I fracture in three cases, a type II fracture in one case and a type III fracture in 16 cases. Three cases were treated nonoperatively with an upper arm cast. 17 children were treated with open reduction and internal fixation. Diagnosis of three fractures was delayed. No postoperative complications such as infections, nerve damage or nonunions. 15 children showed free elbow function. Three children showed slightly restricted elbow extension by less than 10° and two by 10°-20°. All children showed free pro/supination. 18 children showed a physiological and bilaterally identical arm axis compared to the uninjured side. Two children showed a slightly increased cubitus valgus with a 5 - 10° difference between sides. Radiologically, two children with delayed fracture treatment showed partial necrosis of the trochlea. The Mayo Elbow Score showed good (2) to excellent results in all children (18).Very good clinical and functional results can be expected if the injury is diagnosed without delay followed by adequate therapy. Misdiagnosis of ulnar condyle fractures can be associated with the development of nonunions and functional restrictions as well as, after operative therapy, trochlear necrosis. Children up to the age of 6 in particular are at risk of misdiagnosis due to faulty assessment of the cartilaginous trochlea.Die Fraktur des Condylus ulnaris humeri ist eine sehr seltene Salter-Harris-IV-Verletzung des kindlichen Ellenbogens. Aufgrund stetiger radiologischer Veränderungen am Ellenbogen mit unterschiedlichem Auftreten der Ossifikationskerne sowie einer späten Ossifikation der Trochlea ist die Diagnosestellung eine Herausforderung. Um Langzeitkomplikationen zu vermeiden, sollte dem behandelnden Chirurgen das seltene Krankheitsbild, die Diagnostik und adäquate Therapie bekannt sein.Im Rahmen einer retrospektiven Untersuchung wurden alle Kinder erfasst, die eine Condylus-ulnaris-Fraktur zwischen 2002 und 2019 erlitten haben und an einer einzelnen kindertraumatologischen Schwerpunktklinik primär oder sekundär behandelt wurden. Das Follow-up betrug mindestens 12 Monate. Im Rahmen einer klinischen Nachuntersuchung wurde der Bewegungsumfang, die Gelenkstabilität in Valgus- und Varusstress sowie die Achsenverhältnisse im Seitenvergleich überprüft. Zur Objektivierung der funktionellen Ergebnisse wurde der Mayo-Ellenbogen-Performance-Score verwendet.20 Kinder mit einem Durchschnittsalter von 8,6 Jahren (4 – 13) und einer durchschnittlichen Nachbeobachtungszeit von 25 Monaten konnten eingeschlossen werden. Die radiologische Auswertung anhand der Jakob-Fowles-Klassifikation ergab eine Typ-I-Fraktur in 3 Fällen, eine Typ-II-Fraktur in 1 Fall sowie eine Typ-III-Fraktur in 16 Fällen. Bei 3 Kindern wurde eine konservative Behandlung mit Oberarmgips durchgeführt, bei 17 Kindern eine offene Reposition und osteosynthetische Versorgung. Bei 3 Frakturen erfolgte eine verspätete Diagnosestellung. Es traten keine postoperativen Komplikationen wie Infekte, Nervenschäden oder Pseudarthrosen auf. 15 Kinder zeigten eine freie Funktion des Ellenbogens. Drei Kinder zeigten ein leichtes Streckdefizit von unter 10° und 2 Kinder ein Streckdefizit von 10 – 20°. Alle Kinder hatten eine freie Unterarmumwendbewegung. 18 Kinder zeigten eine physiologische und seitengleiche Armachse. Zwei Kinder zeigten einen leicht verstärkten Cubitus valgus mit 5 – 10° Seitendifferenz. Radiologisch zeigten 2 Kinder mit verspätet versorgten Frakturen eine partielle Nekrose der Trochlea. Der Mayo-Ellenbogen-Score zeigte gute (2) bis exzellente Ergebnisse bei allen Kindern (18).Wird die Diagnose ohne Verzögerung gestellt sowie eine adäquate Therapie durchgeführt, ist mit einem sehr guten klinisch-funktionellen Ergebnis zu rechnen. Das Nichterkennen einer Condylus-ulnaris-Fraktur kann mit der Entwicklung einer Pseudarthrose mit funktionellen Einschränkungen sowie nach operativer Therapie mit einer Trochleanekrose einhergehen. Kinder bis zum 6. Lebensjahr sind hier besonders betroffen aufgrund der Fehleinschätzung der noch knorpeligen Trochlea.

Nonunions are a very rare complication after surgical treatment of displaced forearm fractures in children, but can occur in both the radius or ulna. The aim of this study is to evaluate predisposing factors for non-unions and to discuss treatment options. We conducted a retrospective analysis of all patients who were treated primarily or secondary at our institution for nonunion after forearm fractures and operative treatment. Therefore, we retrospectively reviewed the medical charts and radiographs of affected patients from 1990 to 2020. We analysed demographic and fracture-related data as well as treatment options. Twenty-seven cases were identified. Median age was 12 years (7–16 years). The ulna was affected in 20 cases and the radius in 7. The most common location for ulna nonunion was the middle third of the shaft, and for the radius the mid and distal shaft. In 21 cases an open reduction was required. In 9 cases technical problems were identified. In most cases (26/27) a hypertrophic nonunion occurred. 10 of 27 (37%) nonunions healed without any surgical management after 9 (7–15) months. The median age of the conservatively managed group was 10 (6–13) years, younger than in the group with managed with reoperation [median 13 (7–16) years]. Indications for surgical intervention were increasing deformity, pain and limitation of movement. Open reduction and technical problems seem to be influencing factors. A conservative approach can be adopted in asymptomatic patients, otherwise an operative management, constituting plate osteosynthesis with or without bone grafting, should be performed.

ZusammenfassungDie Behandlungsprinzipien von Frakturen beim Kind richten sich nach den besonderen Eigenschaften der Frakturheilung am wachsenden Skelett. Das Skelett des Kindes stellt ein vom Alter abhängiges dynamisch wachsendes Organ dar, mit der Fähigkeit, schnell knöcherne Verletzungen zu heilen, mit hoher Toleranz gegen Weichteilverletzung, geringen Immobilitätsschäden und altersabhängig möglicher Korrektur von posttraumatische Fehlstellungen. Diese Fähigkeiten sind am Skelett des Kindes nicht überall gleich, sie sind direkt abhängig von Potenz der angrenzenden Wachstumsfuge bzw. ihrem Anteil an der Gesamtlänge der Extremität und dem Alter des Kindes. Der Behandler von Frakturen und Verletzungen des Kindes benötigt spezielle Kenntnisse über die Besonderheiten des wachsende Organs „Skelett“, muss aber auch über die Bedürfnisse des Kindes und seiner Bezugspersonen reflektieren können. Bestehen Ungereimtheiten hinsichtlich des Unfallmechanismus und der Verletzung, eine verzögerte Vorstellung nach Fraktur oder spezielle Frakturen, dann muss an eine Kindesmisshandlung gedacht werden. Es gilt, die Balance zu halten zwischen den Polen „bei Kindern wächst sich alles aus“ und der apodiktischen Entscheidung einer primären definitiven Versorgung, die überspannt in jedem Lebensalter zu einer operativen Versorgung führt.

ZusammenfassungDer kindliche Knick-Senk-Fuß ist eine 3-dimensionale Fußfehlstellung mit vermehrter Valgusstellung der Ferse, Abflachung der medialen Längswölbung und Abduktion des Vorfußes. Man unterscheidet die flexible von der kontrakten (rigiden) Form. Die Diagnostik gliedert sich in Anamnese, klinische Untersuchung, apparative Diagnostik wie Pedobarografie und die Ganganalyse sowie bildgebende Verfahren. Wichtig ist die Einbeziehung in ein Therapieschema von eventuell vorliegenden pädiatrischen oder neuropädiatrischen Erkrankungen (z. B. Muskeldystrophien, Ehlers-Danlos- oder Marfan-Syndrom u. Ä.). Es zeigt sich, dass bei Kindern ≤ 6 Jahre der flexible Knick-Senk-Fuß fast ausschließlich physiologisch vorkommt (bei 97% aller 19 Monate alten Kinder). Bis zum Alter von 10 Jahren bildet sich die mediale Fußlängswölbung zunehmend aus. Bei einem kleinen Anteil (10-jährige Kinder 4%) persistiert der Knick-Senk-Fuß oder wird progredient. Oberhalb von 10 Jahren besteht die Gefahr der Dekompensation mit zunehmender Rigidität. Nur die Minderheit der Kinder entwickelt eine Schmerzsymptomatik (

The medial condyle fracture of the humerus is-in comparison to the lateral condyle fracture-a very rare Salter-Harrison IV-fracture of the elbow. In this prospective study 14 children were included and reviewed. One child had minimal displacement fracture type I, one child had type II, and 12 children had type III-fractures. One patient was treated conservatively by an upper arm cast; thirteen were surgically treated using open reduction and osteosynthetical treatment. Postoperatively the elbow was immobilized in 90° flexion and neutral position in a long-arm cast for 4-6 weeks. In 11 children the diagnosis was made immediately after trauma, in 3 children the fracture was overlooked initially. Medial condyle fractures may be difficult to diagnose in children younger than 6 years and the lesion may be mistaken for a simple avulsion of the medial epicondyle or even missed. The C-sign is a hint for a medial condyle fracture. The development of nonunion happens in consequence of failure to recognize the fractures. Results after an average follow-up of 36 months showed that children who were diagnosed immediately and received operative stabilization had very good functional and aesthetical results. Three children with delayed diagnosis of the fracture had open surgery with reposition and osteosynthetical fixation. In two of the overlooked cases a slight contracture and angular misalignment persisted. If in this injury the diagnosis is made without delay, an appropriate therapy is implemented and radiographical controls are performed until consolidation, good results can be expected. The main risk in medial condyle fractures of the humerus is to overlook them. This can lead to the development of a nonunion with joint malformations.

The modified Dunn osteotomy (MDO) gained popularity for the treatment of moderate-to-severe SCFE over the past years, even though both indications and outcomes are currently debated. The aim of this study is to evaluate results and complications of MDO consecutively performed at a single institution for severe slipped capital femoral epiphysis (SCFE) (slip angle ≥ 60°). In this retrospective clinical study, 23 hips (22 patients) were treated with MDO (2009–2015). SCFE was classified according to stability, slip angle, and as chronic/acute. Clinical assessment was performed with clinical examination and nonarthritic hip score (NAHS), modified Harris hip score (mHHS), and short form 12 (SF-12) outcome scores. Residual deformity, avascular necrosis (AVN), and osteoarthrosis (OA) were measured on plain radiographs. The mean slip angle was 70° (range 60–90); 17 of 23(74%) patients had a chronic SCFE, 6 of 23(26%) had acute-on-chronic SCFE, and 1 of 23(4%) had an unstable SCFE. The mean age at surgery was 14 years (range 11–17). At 3 years follow-up (range 1–7), 4 of 23(17%) patients had an AVN or AVN progression, one of these needing a hip arthroplasty. All the cases of AVN or AVN progression were diagnosed within the first year after surgery and there was an association between AVN and operation date (with more AVN among patients operated earlier). Out of 23 patients, 2 (9%) had an implant mobilization or failure and needed a revision surgery without further complications, 1 (4%) developed an asymptomatic heterotopic calcification, and another a partial implant removal without clinical consequence. At follow-up, the slip angle was 9° (range 1–15) and outcome scores were improved. MDO is a demanding technique which allows a near anatomical correction of SCFE and the overall complication rate is not negligible. With actual data, the authors only recommend this procedure for specialized centers, performed by experienced high-volume surgeons, and for severe displaced SCFE (≥50°). The long-term results must be closely monitored and compared with the natural history and other treatment options. This study was a Level IV retrospective study in a case series.

The aim of this study is to evaluate the clinical, radiographic short-term results and complications after surgical hip dislocation in young patients (≤18 years). Clinical and radiographic outcomes were assessed in patients who underwent a surgical hip dislocation Ganz-type approach between 2008 and 2012. Diagnosis included Legg–Calve–Perthes disease, slipped capital femoral epiphysis, femoroacetabular impingement, osteonecrosis of the femoral head, multiple hereditary exostoses and pigmented villonodular synovitis. Clinical data, the modified Harris hip score, nonarthritic hip score, 12-item short form health survey, the Stulberg classification, morphometric indexes, signs of osteonecrosis and osteoarthrosis were used for the evaluation. After a mean 3 years follow-up (range 0.5–6 years), 53 hips (51 patients) were evaluated. The most common diagnoses were Legg–Calve–Perthes disease, slipped capital femoral epiphysis, femoroacetabular impingement and multiple hereditary exostoses. Mean age at surgery was 14 years (range 10–18 years). Through this approach femoral head-neck osteoplasty, Dunn-type osteotomy, labrum refixation, synovectomy, femoral head mosaicplasty open reduction and fixation for slipped capital femoral epiphysis were performed, finally in association with pelvic or intertrochanteric osteotomy. At follow-up, better outcome scores were obtained, progression of the osteonecrosis of the femoral head was observed in four cases and three further patients required the implant of a total hip prosthesis. After 3 years follow-up, results are comparable to previous studies and patients have a high rate of satisfaction, however the effectiveness of those procedures have to be proved on the long term. Results and complications seem to be related with preoperative lesion(s) and type of treatment. Level IV, retrospective study, case series.

Sehr geehrte Leserin, sehr geehrter Leser, in Abb. 1b wurde die Ausstelllinie nach Graf versehentlich zu steil eingezeichnet und damit auch der Betawinkel nach Graf falsch dargestellt. Wir bitte, die korrigierte Darstellung des Betawinkels nach Graf in Abb. 1b zu berucksichtigen. Die Darstellung …

The mechanisms of densification in spark plasma sintering (SPS) were investigated both analytically and numerically for a model system of two spherical metallic powder particles. From the microscopic temperature distribution, the possibility of a micro-local overheating of the particle-particle contacts was analysed for different particle sizes, contact geometries, materials, and electrical loads. It is shown that, for particles below the size of one millimetre, local overheating is below one Kelvin. Subsequently, the material transport by thermomigration, electromigration, and diffusion driven by surface curvature and external pressure was derived from microscopic field distributions obtained from analytical calculations and finite-element simulations. The results show that, while the mechanical pressure accelerates material transport by orders of magnitude, the electrical current and the temperature gradients do not. It is also shown that pulsing the current has no significant influence on the densification rate.

Tibial tubercle avulsion fractures are rare, they represent less than 1% of all physeal fractures. Compared to monolateral tibial tubercle avulsion fractures, bilateral occurrence is even rarer. The purpose of this study is to report about the so far largest group of bilateral avulsion fractures and to compare them to unilateral fractures as well as to current literature.All patients who suffered from bilateral tibial tubercle fractures between January 2009 and March 2019 were included. All medical records and radiographs were reviewed and a clinical follow-up was performed. The examined criteria were age, gender, mechanism of injury, classification, risk factors, complications, management and outcomes. Clinical outcome was measured using the well established Tegner activity scale and Lysholm-Gillquist score. The same criteria were analyzed in a literature review of bilateral tibial tubercle fractures to compare our results to available literature.We found four children with bilateral tibial tubercle avulsion fractures. All patients were male with a mean age of 14.5 ± 0.7 years (13 - 15). Mean follow-up examination was 13.6 ± 6.5 months (8 - 29) after surgery. The avulsions occurred during jumping activities in all cases. All children could no longer stand or move because of sudden pain in the knee. We found type IV fractures in three cases, type III fractures in four cases and one type V fracture according to the Ogden classification. All children were treated by open or closed reduction and stabilization with screws or K-wires. Follow-up showed complete fracture healing without complications in all patients. There were no changes in Tegner activity scale and Lysholm-Gillquist Score and knee function comparable to prior to the accident was achieved in all cases.Good clinical results without restrictions regarding function of the knee joint can be achieved by direct operative treatment of bilateral tibial avulsion fractures. A reduction in sporting activity has not to be expected. There were no differences between bilateral or unilateral tibial tubercle avulsion fractures.Bei der Avulsionsfraktur der Tuberositas tibiae handelt es sich um eine seltene Verletzung im Wachstumsalter. Das simultane Auftreten der beidseitigen Verletzung ist eine Rarität. Langzeitkomplikationen im Sinne von Achsdeformitäten und Beinlängendifferenzen sind zu vermeiden. Im Rahmen der vorliegenden Arbeit sollen klinische Ergebnisse der beidseitigen Verletzung anhand der bislang größten publizierten Fallserie dargestellt und mit klinischen Ergebnissen der einseitigen Verletzung verglichen werden.Alle Jugendlichen, die zwischen Januar 2009 und März 2019 monozentrisch an einer kindertraumatologischen Schwerpunktklinik aufgrund einer beidseitigen Avulsionsverletzung der Tuberositas tibiae behandelt wurden, konnten bis zum Schluss der Wachstumsfugen klinisch sowie radiologisch nachuntersucht werden. Das klinische Ergebnis wurde mittels Tegner-Aktivitätsscore sowie Lysholm-Gillquist-Score retrospektiv zum Zeitpunkt vor dem Unfall sowie zum Zeitpunkt der letzten Follow-up-Untersuchung bestimmt. Alle Frakturen wurden anhand der modifizierten Ogden-Klassifikation eingeteilt. Patientenspezifische Parameter wurden aus dem Krankenhausinformationssystem entnommen. Anhand einer Literaturrecherche wurden die Ergebnisse mit den bislang publizierten Fällen zur beidseitigen/einseitigen Verletzung verglichen.Vier Patienten (8 Fälle) konnten zur weiteren deskriptiven statistischen Auswertung eingeschlossen werden. Das Alter zum Unfallzeitpunkt betrug 14,5 ± 0,7 Jahre (13 – 15). Das letzte Follow-up erfolgte 13,6 ± 6,5 Monate (8 – 29) nach dem Unfallereignis bei Verschluss der Wachstumsfugen. Nach modifizierter Ogden-Klassifikation zeigte sich in 3 Fällen eine Typ-IV-Verletzung, in 4 Fällen eine Typ-III-Verletzung und in 1 Fall eine Typ-V-Verletzung. In allen Fällen erfolgte die unmittelbare operative Versorgung mittels Schrauben bzw. K-Draht-Osteosynthese. Es konnte in allen Fällen das Aktivitätslevel vor dem Unfallereignis wieder erreicht werden. Tegner-Aktivitätsscore sowie Lysholm-Gillquist-Score zeigten keine Veränderungen zum Ergebnis vor dem Unfallereignis.Mittels direkter operativer Versorgung im Sinne einer offenen oder geschlossenen Reposition und Stabilisierung mittels Schrauben- und/oder K-Draht-Osteosynthese können sehr gute klinische Ergebnisse mit voller Kniegelenkfunktion und geringen Komplikationsraten nach Schluss der Wachstumsfugen erzielt werden. Eine Rückkehr in die vorherige sportliche sowie Alltagaktivität ist zu erwarten. Im Hinblick auf Alter, Geschlecht, Unfallursache sowie das klinische Ergebnis ergibt sich kein Unterschied zum in der Literatur beschriebenen unilateralen Verletzungsmuster.

Purpose Children with sonographic grade IV hip dysplasia according to Graf and with failed conservative treatment usually need surgical reduction afterwards. Surgical reduction of the hip can lead to severe complications, the occurrence of residual acetabular dysplasia, osteonecrosis, redislocation and other postoperative complications. This paper investigates whether arthroscopic reduction is a promising alternative to open reduction. Methods We retrospectively examined 66 patients (78 hips) who were not older than two years at the first time of surgery. Arthroscopic reduction was performed on 17 children (19 hips) and open reduction on 49 children (59 hips). Patient records were used to determine redislocation, postoperative complication and residual dysplasia. Radiographs were used to determine Tönnis classification for osteonecrosis and pathological acetabular (AC) angle for residual dysplasia. We considered data up to a two-year follow-up. Statistical evaluation was performed with binary logistic regression. Results After arthroscopic reduction, 6% showed osteonecrosis, compared with 20% with open reduction (p = 0.334). Redislocation was not observed after arthroscopic reduction but for 29% after open reduction (p = 0.005). An improvement of femoral head coverage was achieved with residual dysplasia of 23.5% after arthroscopic reduction, compared with 62% after open reduction (p = 0.002). Conclusion The arthroscopic procedure represents a meaningful alternative to the open procedure due to a lower complication rate, a safe setting, a lower rate of residual dysplasia, no observed redislocation and occurrence of osteonecrosis only once in the arthroscopic group of developmental dysplasia of the hip. The arthroscopic procedure should be tested in further studies and in other clinics in order to broaden the empirical base. Level of Evidence Level III (retrospective cohort study)

Hip dysplasia is one of the most common disorders in paediatric orthopedics. With the development of ultrasound techniques treatment has changed, and earlier diagnosis and treatment is possible. So, for more than 20 years diagnosis and treatment has been focused on ultrasound. Many papers reporting new diagnostic techniques like MRI have been published. Arthroscopic reduction is a new surgical procedure. However, established surgical procedures continue to play an important role in the treatment.This paper presents new and established diagnostic techniques, conservative and surgical treatment options. Unfortunately, due to the great number of publications, not all aspects could be taken into account. In particular, we describe the diagnostic and treatment standards in German-speaking countries based on ultrasound hip screening. However, also international aspects of diagnostic and treatment options have been included.

The initial stage of contact formation during field-activated/assisted sintering of powders is investigated experimentally and numerically for spherical particles of nickel, steel, and copper. The results of experimental studies of the contact resistance and the neck formation process due to melting/sintering in two- to three-particle systems under a single high-current pulse from a capacitor discharge are compared with results of fully coupled thermo-electrical finite-element simulations. The impact of particle size, contact geometry, and electrical load on the temperature and temperature gradient distribution during the pulse discharge is analyzed numerically for nickel spheres. The influence of the material itself is compared for nickel, steel, and copper systems.

ZusammenfassungFußfehlstellungen im Kindes- und Jugendalter beschäftigen sowohl den Kinderarzt als auch den Orthopäden. Harmlose Fußfehlhaltungen müssen dabei von strukturellen Deformitäten unterschieden werden, bei denen eine Therapie notwendig wird. Im folgenden Artikel sollen die häufigsten Fußfehlstellungen im Kindes- und Jugendalter dargestellt werden.

Contact growth and temperature behavior in time during a single high-current pulse representing the initial stage of field-assisted/spark plasma sintering (FAST/SPS) have been studied experimentally and numerically. The measured evolution of the electrical resistance and of the neck formation process in two-particle systems is compared to the results obtained from the fully coupled thermo-electro-mechanical finite element simulations. The results of simulations with various models of inelastic deformation show that the viscoelastic/viscoplastic material model provides a realistic contact growth in initial stage of FAST/SPS. The impact of electrical and mechanical loads, material parameters and particle size on temperature, on inelastic strain distribution and on densification has been studied by finite element simulations for copper, stainless steel and nickel particles.

In pediatric flat foot a differentiation has to be made between the flexible and the rigid form. The diagnosis is based on the history, clinical examination as well as pedobarography, gait analysis and imaging techniques. It is important to rule out neuropediatric conditions such as muscular dystrophies, Ehlers-Danlos- or Marfan syndrome. In children six years of age and younger a flexible flat foot is nearly always physiological (97% of all 19 months old children). Up to the age of ten years the medial column of the foot is developing. Only a minority of children (4% in ten year olds) has a persistent or progressive deformity. Beyond to age of ten there is a danger of deformity decompensation as well as an increased rigidity. Only a minority of children develops some pain ( 2%). A clear risk factor for persistent pediatric flat foot is obesity (62% of six year old children with flat foot are obese). Pathogenetic factors include muscular, bony or soft tissue conditions. However, there specific rule is still unclear. Prevention consists in a thorough parent information about the normal development as well as encouragement of regular sportive activities. Soft and large enough shoes should be carried as a protection. Barfoot walking has to be encouraged on uneven grounds. If physiotherapy is needed different methods can be applied. Orthosis treatment should include a proprioceptive approach. Surgical interventions in children are rare. If surgical treatment is planned a detailed algorhythm should be used before utilizing one of the many different surgical methods.Der kindliche Knick-Senk-Fuß ist eine 3-dimensionale Fußfehlstellung mit vermehrter Valgusstellung der Ferse, Abflachung der medialen Längswölbung und Abduktion des Vorfußes. Man unterscheidet die flexible von der kontrakten (rigiden) Form. Die Diagnostik gliedert sich in Anamnese, klinische Untersuchung, apparative Diagnostik wie Pedobarografie und die Ganganalyse sowie bildgebende Verfahren. Wichtig ist die Einbeziehung in ein Therapieschema von eventuell vorliegenden pädiatrischen oder neuropädiatrischen Erkrankungen (z. B. Muskeldystrophien, Ehlers-Danlos- oder Marfan-Syndrom u. Ä.). Es zeigt sich, dass bei Kindern ≤ 6 Jahre der flexible Knick-Senk-Fuß fast ausschließlich physiologisch vorkommt (bei 97% aller 19 Monate alten Kinder). Bis zum Alter von 10 Jahren bildet sich die mediale Fußlängswölbung zunehmend aus. Bei einem kleinen Anteil (10-jährige Kinder 4%) persistiert der Knick-Senk-Fuß oder wird progredient. Oberhalb von 10 Jahren besteht die Gefahr der Dekompensation mit zunehmender Rigidität. Nur die Minderheit der Kinder entwickelt eine Schmerzsymptomatik ( 2%). Ein Risikofaktor zur Persistenz des Knick-Senk-Fußes stellt das Übergewicht im Kindesalter dar (62% der 6-Jährigen mit Knick-Senk-Fuß sind übergewichtig). Pathogenetische Faktoren können muskulär, knöchern und bindegewebig sind, wobei hier der Einfluss der unterschiedlichen Faktoren kontrovers diskutiert wird. Die Hauptprävention besteht in einer umfassenden Aufklärung über eine normale kindliche motorische Entwicklung. Daraus resultiert die Eigenförderung der physiologischen Entwicklung durch tägliche Bewegung, das Anstreben eines normalen Gewichtes, das Tragen von weichen Schuhen mit ausreichender Länge und Weite zum Schutz und das Barfußlaufen auf wechselnden Untergründen. Im Falle einer nötigen Intervention kann Physiotherapie inklusive manueller Techniken nötig werden. Eine Einlagen- oder Orthesenversorgung sollte bevorzugt mit einer sensomotorischen Bettung erfolgen. Operative Eingriffe sind selten. Im Falle einer geplanten operativen Intervention muss ein differenziertes Indikationsschema angewandt werden. Verschiedenste operative knöcherne und weichteilige Methoden stehen zur Verfügung.

A new, modified molecular structural mechanics model for the determination of the elastic properties of carbon nanotubes is presented. It is designed specifically to overcome drawbacks in existing molecular structural mechanics models, which are not consistent with their underlying chemical force fields in terms of energy. As a result, modifications are motivated, developed and implemented in order to create a new, energy consistent molecular structural mechanics model. Hence, the new model leads to a better prediction of the material parameters for single wall carbon nanotubes, while the simple applicability of the approach is maintained. The results calculated for the elastic constants (Young's modulus, Poisson ratio) of armchair and zig-zag CNTs are given and discussed. Both elastic constants were found to be dependent on the chirality as well as on the carbon nanotube diameter. An asymptotic value of approximately 800 GPa was obtained for the Young's modulus and a value of approximately 0.28 for the Poisson ratio.

Purpose The purpose of this study was to describe the anatomy as seen arthroscopically, the role of the labrum and its relevance in luxation and reduction procedures, and secondary changes to the cartilaginous acetabular roof and to determine the main obstacles preventing reduction of dislocated hips in infants and young children. Methods A specialized pediatric medial approach to hip arthroscopy was performed on 25 hip joints in 21 patients younger than 4 years of age. The arthroscopic procedure was conducted using a 2.7-mm cannulated instrument. A subadductor portal was used for the 70° arthroscope, and a high anterolateral portal served as a working portal. The anatomic findings of the individual hip joints were recorded. We examined the femoral head, the teres ligament, the transverse ligament, the acetabulum, and the acetabular labrum. The obstacles preventing reduction were successively resected. Results An arthroscopic investigation of all major structures and arthroscopic reduction was possible in 25 hip joints. A hypertrophic teres ligament was present in 23 of the 25 hips. Capsular constriction prevented reduction in 22 of the 25 hips. The acetabular labrum was not inverted in any of the examined hip joints and was also never an obstacle to reduction. Secondary changes to the cartilaginous preformed acetabular roof were present in 10 hips. Conclusions We have shown that arthroscopy of a developmentally dislocated hip can be safely performed using the subadductor portal. Through this arthroscopic approach, we were able to identify the previously described pathologic structures—the limbus, neolimbus, pulvinar, hypertrophic teres ligament, and capsular constriction. The capsule was the most common block to reduction, followed by the teres ligament. Successful reduction can be achieved by removal of intra-articular tissues, the pulvinar, and the teres ligament, and nearly always a capsular release. The limbus and neolimbus were not factors in achieving reduction in our series. Level of Evidence Level IV, case series.

Flatfoot is a severe complication of extensive clubfoot surgery. In this retrospective study, we evaluated our results following flatfoot surgery in overcorrected clubfeet. The aim was to analyze the success of different surgical techniques, including tarsal osteotomies and arthrodesis, in correcting different types of flatfeet. Between January 1, 2011 and December 31, 2015 we treated 25 severe cases of flatfeet after extensive clubfoot surgery. We classified the hindfoot deformities into rotational valgus, hinge valgus or translatory valgus based on AP standing X-rays. Tarsal osteotomies (Mitchell, Evans, Cotton) and arthrodesis were adapted based on age and severity. Age, gender, pain, hindfoot valgus and function were documented. Function and X-rays were compared pre- and postoperatively. There were 17 male and 4 female patients. Age at operation ranged from 11 to 26 years with an average age of 14.3 years. The mean follow-up was 27.6 months (7–60 months). Primary surgical treatment was a tarsal osteotomy in 19 cases and in six cases it was arthrodesis. Hindfoot valgus (O 18.6°–3.2°), calcaneal pitch (O 6.2°–14.6°), Costa Bartani angle (O155°–142°) and Meary angle (O 2.0°–8.8°) improved pre- to postoperatively. Range of motion did not improve after surgical correction. 81% were satisfied with the postoperative results. All flatfeet with translatory valgus, initially treated with a tarsal osteotomy, needed further arthrodesis due to primary undercorrection. Tarsal osteotomies are successful methods for correcting flatfeet following extensive clubfoot surgery with rotational valgus and mild hinge valgus. Tarsal osteotomies are unable to successfully correct flatfeet that have a translatory valgus. In such cases, we recommend double or triple arthrodesis. The functional outcome is limited by the preop range of motion and the appearance of talus deformities.

The outstanding properties of carbon nanotubes (CNTs) keep attracting the attention of researchers from different fields. CNTs are promising candidates for applications e.g. in lightweight construction but also in electronics, medicine and many more. The basis for the realization of the manifold applications is a detailed knowledge of the material properties of the carbon nanotubes. In particular for applications in lightweight constructions or in composites, the knowledge of the mechanical behavior of the CNTs is of vital interest. Hence, a lot of effort is put into the experimental and theoretical determination of the mechanical material properties of CNTs. Due to their small size, special techniques have to be applied. In this research, a modified molecular structural mechanics model for the numerical determination of the mechanical behavior of carbon nanotubes is presented. It uses an advanced approach for the geometrical representation of the CNT structure while the covalent bonds in the CNTs are represented by beam elements. Furthermore, the model is specifically designed to overcome major drawbacks in existing molecular structural mechanics models. This includes energetic consistency with the underlying chemical force field. The model is developed further to enable the application of a more advanced chemical force field representation. The developed model is able to predict, inter alia, the lateral and radial stiffness properties of the CNTs. The results for the lateral stiffness are given and discussed in order to emphasize the progress made with the presented approach.

Wahrend die adaquat versorgte akute Monteggia-Lasion eine sehr gute Prognose hat, sind die Behandlungsergebnisse bei veralteten Monteggia-Frakturen sehr unterschiedlich. Durch ein groseres Verstandnis der gesamten Verletzungen am Ellenbogen haben sich die Resultate deutlich gebessert. Verbleibt der Radiuskopf in einer Luxationsstellung, kommt es zu einer Fehlentwicklung am Radioulnar- und Radiohumeralgelenk.

Carbon nanotubes are due to their outstanding mechanical properties destined for a wide range of possible applications. Since the knowledge of the material behavior is vital regarding the possible applications, experimental and theoretical studies have been conducted to investigate the properties of this promising material. The aim of the present research is the calculation of mechanical properties and of the mechanical behavior of single wall carbon nanotubes (SWCNTs). The numerical simulation was performed on basis of a molecular mechanics approach. Within this approach two different issues were taken into account: (i) the nanotube geometry and (ii) the modeling of the covalent bond. The nanotube geometry is captured by two different approaches, the roll-up and the exact polyhedral model. The covalent bond is modeled by a structural molecular mechanics approach according to Li and Chou. After a short introduction in the applied modeling techniques, the results for the Young\'s modulus for several SWCNTs are presented and are discussed extensively. The obtained numerical results are compared to results available in literature and show an excellent agreement. Furthermore, deviations in the geometry stemming from the different models are given and the resulting differences in the numerical findings are shown. Within the investigation of the deformation mechanisms occurring in SWCNTs, the basic contributions of each individual covalent bond are considered. The presented results of this decomposition provide a deeper understanding of the governing deformation mechanisms in SWCNTs.

Molecular mechanics models like the molecular structural mechanics (MSM) model have been proven to be a valuable tool for the investigation of carbon nanotubes. This class of models is based on a chemical force field representing the bonds present in the structure. Up to now, the underlying chemical force field applied in the MSM model is usually based on harmonic potentials. This simple approach comes with major drawbacks limiting the abilities of the MSM approach. In order to overcome these limitations, the present work integrates the 2nd generation reactive bond order potential (REBO), which is a sophisticated chemical force field, into the MSM approach. The development of this advanced MSM model is given in detail. As a demonstration of its capabilities, the elastic properties of different armchair and zig-zag CNTs are investigated numerically. It was found, that the results for the elastic properties differ significantly with the choice of the underlying chemical force field. The arising differences are discussed and reasons for the occurring behavior are given. The developed advanced MSM approach on the basis of the REBO potential strongly enhances the capabilities of the MSM approach while maintaining its excellent accessibility and applicability together with a low computational effort.

Hintergrund: Die Behandlung der Huftgelenksinstabilitat bei Kindern mit dem Down-Syndrom ist eine grose Herausforderung. An unserem Klinikum wurden im zeitlichen Verlauf zur operativen Behandlung verschiedene Beckenosteotomien und Korrektureingriffe am proximalen Femur durchgefuhrt. Ziel dieser retrospektiven Studie ist es, diese durchgefuhrten Operationsverfahren auf das postoperative klinische und radiologische Ergebnis zu untersuchen. Material und Methoden: Die Patienten rekrutierten sich aus einem Gesamtkollektiv von 166 Patienten mit dem Down-Syndrom. Von diesen waren 63 Patienten wegen Huftgelenksproblemen in Behandlung. Ausschlieslich die operativ versorgten Patienten wurden in diese Studie eingeschlossen. Die vollstandig vorhandenen Patientenakten und Rontgenbilder dieser 31 Patienten wurden hinsichtlich folgender Parameter ausgewertet: Auftreten der Huftgelenksbeschwerden, Begleiterkrankungen, zeitliche Progredienz der Erkrankung, ausgewahltes OP-Verfahren und dessen Zeitpunkt, Lange des stationaren Aufenthalts, Nachbehandlung und etwaige Reoperationen aufgrund von Komplikationen, AC-Winkel, CE-Winkel, ACM-Winkel, CCD-Winkel, Migrationsindex nach Reimers, Kongruenzstufen nach Bauer und Kerschbaumer sowie allgemeine Morphologie des Femurkopfs. Um einen Vergleich der Krankheitsverlaufe mit Kindern ohne Trisomie 21 stellen zu konnen, wurden – im Sinne einer Matched-Pair-Analyse – 18 Patienten mit kongenitaler Huftdysplasie aus der Kartei unseres Klinikums herausgesucht, die sich im selben Jahr einer gleichen Operation unterzogen. Ergebnisse: Insgesamt wurden bei den 31 beobachteten Patienten mit dem Down-Syndrom 49 huftgelenkserhaltende Operationen durchgefuhrt. Diese umfassten 13 Osteotomien nach Chiari, 11 Triple-Osteotomien nach Tonnis, 10 reine intertrochantare derotierende Varisationsosteotomien (IDVO), 8 Azetabuloplastiken nach Pemberton, 5 Beckenosteotomien nach Salter und 2 offene Huftgelenksrepositionen. Drei Altersgipfel hinsichtlich Zeitpunkt des operativen Eingriffs liesen sich bei der Morbus-Down-Gruppe feststellen. Bezuglich der Krankheitsverlaufe und der Anzahl aufgetretener Komplikationen unterschieden sich die beiden Gruppen nicht wesentlich. Klinisch und radiologisch uberzeugende Ergebnisse wurden uberwiegend mit reorientierenden Beckenosteotomien erzielt. Bei ausschlieslicher Behandlung mittels IDVO kam es in 50 % der Falle zu Nachoperationen in Form von Beckenosteotomien. Die Hypermobilitat des Muskel- und Bandapparats bei Kindern mit dem Down-Syndrom lies sich im Gegensatz zur Kontrollgruppe anhand des Vergleichs des pra- und postoperativen Bewegungsausmases am Huftgelenk feststellen. Der Vergleich der Rontgen-Beckenubersichtsaufnahmen zeigte bei beiden Gruppen eine signifikante Verbesserung der gemessenen Winkel. Die praoperativ gemessenen Werte fur den AC- und CE-Winkel waren bei der Huftdysplasie-Kontrollgruppe signifikant schlechter als bei den Kinder der Morbus-Down-Gruppe (p

Ziel: Durch die Anderung der Therapie der Unterarmschaftfrakturen von einer eher konservativen zur einer zunehmenden operativen Stabilisierung, insbesondere durch die elastische stabile intramedullare Nagelung (ESIN), treten nun Komplikationen auf, die bisher als solche im Kindesalter kaum beschrieben sind. Uber Pseudarthrosen nach operativ versorgten Unterarmschaftfrakturen des Kindes und der Jugendlichen wird nur vereinzelt, im deutschsprachigen Raum noch gar nicht berichtet. Das Ziel dieser Studie ist es, pradisponierende Faktoren herauszuarbeiten, die nach Operation von Unterarmschaftfrakturen Pseudarthrosen begunstigen. Methode: Im Zeitraum von 1990 bis 2011 wurden alle Kinder mit einer Pseudarthrose nach Unterarmschaftfraktur, die in unserer Klinik behandelt wurden, eingeschlossen. Berucksichtigt wurden alle Kinder, bei denen 6 Monate nach einer Unterarmfraktur noch keine knocherne Konsolidierung ihrer Unterarmschaftfraktur erfolgt war. Ausgeschlossen wurden alle Pseudarthrosen, die eine Grunderkrankung als Ursache hatten. Ergebnisse: Wahrend eines Zeitraums von 21 Jahren wurden 14 Kinder behandelt, welche die Kriterien einer Pseudarthrose erfullten. Von den 14 Kindern waren 9 Kinder auswartig primar behandelt worden und 5 Kinder primar in unserer Klinik. Der Altersdurchschnitt lag bei 10,8 Jahren (7–15 Jahre). Es handelte sich um 13 Ulnaschaft- und um 1 Radiusschaft-Pseudarthrose. Bei 11 Kindern trat die Pseudarthrose im mittleren Drittel auf und bei je 1 Kind im proximalen bzw. distalen Ulnadrittel. 13-mal handelte es sich um Unterarmschaftfrakturen und in 1 Fall um eine Monteggia-Lasion. In 12 Fallen waren die Frakturen geschlossen und in 2 Fallen erstgradig offen. In 9 Fallen war eine offene Ulnareposition durchgefuhrt worden, der Radius war in 4 Fallen offen reponiert worden. Bei 5 Kindern trugen technische Fehler bei der osteosynthetischen Versorgung wesentlich zur Pseudarthrosebildung bei. Funf der 14 Kinder hatten eine Refraktur. Bei 9 Kindern musste ein Revisionseingriff erfolgen. Diese Kinder wurden mit einer Plattenosteosynthese oder ESIN versorgt. Bei 5 Patienten kam es zu einer spontanen Pseudarthroseheilung. In 13 Fallen handelte es sich um hypertrophe und in 1 Fall um eine hypotrophe Pseudarthrose. Schlussfolgerung: Pseudarthrosen am Unterarm nach operativer Versorgung von Unterarmschaftfrakturen treten sowohl bei Kindern als auch bei Jugendlichen im Wesentlichem im mittleren Drittel der Ulna auf. Wird eine offene Reposition notwendig oder handelt es sich um offene Frakturen, so steigt das Risiko einer Pseudarthrose. Auch bei Kindern kann es bei nicht adaquater osteosynthetischer Versorgung zu Problemen bei der Knochenbruchheilung kommen. Trotz des Auftretens von Pseudarthrosen ist die Indikation zur ESIN unzweifelhaft. Das operative Trauma muss bei der offenen Reposition minimal gehalten werden und die Durchblutung des Knochens auch beim Kind respektiert werden.

Arthroscopic hip surgery has become an established diagnostic and therapeutic method for addressing different hip pathologies. This paper focuses on hip arthroscopy for treating hip disorders in children under the age of 10. Arthroscopic hip surgery was performed 30 times on 24 children to address various hip pathologies. Indications were septic arthritis, benign soft tissue tumors, traumatic and congenital hip dislocation, juvenile idiopathic arthritis and osteochondroma of the acetabulum. Diagnostic arthroscopy was technically feasible in all cases. All cases of septic arthritis were successful treated using arthroscopic lavage and antibiotics. In the miscellaneous cases (benign fibrous tumor, juvenile idiopathic arthritis, osteochondroma congenital hip dislocations and traumatic hip dislocation) 4 hips had additional open surgery including surgical dislocation with synovectomy, open reduction and stabilization of the fractured posterior rim of the acetabulum, acetabulopasty and open resection of an osteochondroma with acetabuloplasty. In conclusion arthroscopic hip surgery is an additional diagnostic and therapeutic method that is suitable for treating different hip pathologies in children under the age of 10. Primary treatment of septic arthritis can be done easy by hip arthroscopy. Using cannulated mini arthroscopic hip instruments (2.7 mm), the range of application can be expanded to include treatment of very young infants. Hip arthroscopy can reduce the need of open surgery but cannot replace bony procedures in hip surgery.

Ziel: Der kongenitale Klumpfus ist selten mit einer fibularen oder tibialen Hemimelie assoziiert. Die Behandlung des Klumpfuses ist dabei komplex und umfangreiche operative Masnahmen sind oft notwendig. Wir berichten uber die Ergebnisse nach einer Gipsredression und uber die operativen Masnahmen bei 10 Patienten mit Klumpfusen im Rahmen einer fibularen oder einer tibialen Hemimelie. Material und Methode: Zwischen 1. 1. 2004 und 31. 12. 2009 wurden 398 Klumpfuse an unserem Klinikum primar mit der Gipsredression nach Ponseti behandelt. Insgesamt waren 10 Klumpfuse bei 9 Patienten mit einer fibularen oder tibialen Hemimelie assoziert. Bei 8 Patienten (9 Klumpfuse) wurde primar eine Ponseti-Redression angewandt. Zur Klassifikation der tibialen Hemimelie verwendeten wir die Klassifikation nach Weber und fur die fibulare Hemimelie die Klassifikation nach Achterman und Kalamchi und die Klassifikation nach Paley. Alle Patienten wurden prospektiv erfasst. Dokumentiert wurden die Patientendaten, prospektive Beinlangendifferenz, die zusatzlichen knochernen Fehlbildungen am Klumpfus, operative Masnahmen zur vollstandigen Korrektur und die funktionellen Ergebnisse. Die Ergebnisse wurden vor einem 1. Verlangerungsverfahren beurteilt. Resultate: Vier Patienten hatten eine tibiale Hemimelie, 2 Weber Typ I, 1 Typ 2, 1 Typ 3. Funf Patienten hatten eine fibulare Hemimelie Achterman Kalamchi IA, Paley Typ V. In 1 Fall handelte es sich um eine beidseitige fibulare Hemimelie. Die prospektive Beinlangendifferenz lag zwischen 3,2 und 14 cm. Vier Fuse konnten primar mit einer Gipsredression korrigiert werden. Bei einer fibulotalaren Diastase erfolgte eine knocherne Rekonstruktion einer Malleolengabel mittels Osteotomien. Vier Fuse wurden mit einem posteromedialen Release korrigiert. Bei 4 Rezidiven erfolgten 2-mal ein posteriores Release und 2-mal eine Korrektur mit Losung der Coalitiones und mit Mittelfusosteotomien. Bei einer tibialen Hemimelie Weber 3 erfolgte eine komplexe Rekonstruktion mit Ilisarov-Fixateur und Hexapodenfixateur (Taylor Spatial Frame). Die funktionellen Ergebnisse zeigten in einer Nachuntersuchungszeit zwischen 24–72 Mo. (∅ 42,2 Mo.) eine Dorsalextension zwischen 5 und 20° (∅ 7,7°) und eine Plantarflexion zwischen 10 und 40° (∅ 26,1°). Schlussfolgerung: Die Behandlung kongenitaler Klumpfuse bei tibialer und fibularer Hemimelie mit der Ponseti-Methode ist aufgrund der komplexen Ruckfuspathologie mit Coalitiones limitiert. Nur Klumpfuse bei gering ausgepragten Hemimelien ohne Coalitio konnen mit einer Gipsredression in der Ponseti-Technik primar korrigiert werden. Bei tibialen Hemimelien Weber 2 (tibiofibulare Diastase) kann eine Gipsredression versucht werden. Komplexe operative Korrekturen sind jedoch nicht selten notwendig. Bei hohergradigen Hemimelien empfehlen wir keine Gipsredression. Hier kommen umfangreiche rekonstruktive Masnahmen mit komplexen Osteotomien und Fixateurbehandlungen zur Anwendung.

AIM The Ponseti method is accepted worldwide for the treatment of congenital clubfoot. We report about our experience in a 7-year period. The purpose of the study was to evaluate the history of well treated feet between primary correction and the age of 5-6 years with relapse rate and functional results. MATERIAL AND METHOD Between 1.1.2004 and 31.12.2005 we treated 71 patients with 102 idiopathic clubfeet with the Ponseti method. All patients were prospectively evaluated. We used the Pirani score. The patients' results were documented when the children started to walk and before primary school. The results were compared and statistically evaluated. We used the McKay score and measured the talocalcaneal angle on lateral and a. p. radiographs. RESULTS 89 % clubfeet were successful treated with the Ponseti method. At walking age plantar flexion was between 30° und 50° (∅ 42°) and dorsiflexion between 5° and 30° (∅ 25°). Before primary school plantar flexion was between 30° and 50° (∅ 37,8°) and dorsiflexion between 0° and 25° (∅ 13,9°). Using the McKay score we had 91 % excellent or good results. 31 % cases had surgical treatment of a relapse. In the relapse group 82 % had an excellent or good result according to the McKay score. CONCLUSION The Ponseti method is a very effective technique to treat idiopathic clubfeet. In the first 5 to 6 years of age there is a significant loss of range of motion. The relapse rate is comparable to those of other clubfoot treatment concepts. The relapse treatment of the Ponseti technique, with recasting, tibialis anterior tendon transfer and Achilles tendon lengthening leads to good functional results.

Aim The widely accepted treatment of vertical talus after casting is correction by extensive surgery. Dobbs described a new method for the treatment of vertical talus by casting and minimally invasive surgery. The purpose of the present study was to evaluate the efficacy of this new method. Material and method Between 11/06 and 11/09 we treated 7 patients with 12 vertical tali. Treatment followed the protocol of Dobbs. The initiation of treatment, number of casts, surgery, as well as clinical and radiological results were documented. To evaluate the radiological result we used the Hamanishi score. Results From the beginning all feet could be treated successfully with the Dobbs method. According to the Hamanishi classification we have four excellent and five good results. Two feet had a relapse with subluxation or dislocation of the talonavicular joint. Conclusion Treatment of vertical talus with the Dobbs method is successful. Extensive surgery could be reduced. We recommend the method as primary treatment for vertical talus.

Aim The evaluation of paediatric thoracic or lumbar compression fractures can be challenging. The anatomy of the growing spine often makes a correct diagnosis by plain radiography difficult. The aim of our study was to compare the diagnostic reliability of X-Ray and that of magnetic resonance imaging in the evaluation of acute compression fractures of the paediatric spine. Method From January to December 2008 20 patients (12 boys, 8 girls) who were treated because of clinically suspected compression fractures of the vertebra were included in our study. The average age was 8.3 years. In all cases a radiograph in two planes and an MRI of the lumbar and thoracic spine were obtained. Two orthopaedic surgeons and one radiologist retrospectively assessed the radiographs. The results were compared with the MRI findings. Results In six cases the MRI was normal, in one case there was only a bone bruise without compression of the vertebra. 13 children had two or more than two minor compression fractures (29 fractures altogether). The 5th and 6th thoracic vertebra predominated. In only two cases there was a corresponding result of all three physicians and the MRI. In 4 cases the observers agreed on the localisation of the fracture. There was no agreement about the number of fractured vertebrae. Conclusion An exact evaluation of minor compression fractures of the pediatric spine with plain X-ray was not satisfactory.

Osgood-Schlatter syndrome is a common disease with pain over the tibial tuberosity. Sporting activities that involve jumping and running (e.g. soccer, basketball, volleyball or running) lead to repetitive strain to the tibial tuberosity with traction apophysitis. Treatment depends on the severity of the pain syndrome with modification of sports activities, nonsteroidal inflammatory drugs or immobilisation. The overall prognosis is good with some discomfort in kneeling and activity restriction in some cases. Only in a few cases surgical excision of ossicles and tuberculoplasty may be necessary.

Treatment of displaced radial neck fractures is challenging. Between 1993 and 2006, we treated 63 children using the closed intramedullary pin reduction technique according to Metaizeau in our department. In a retrospective study, associated injuries and complications were evaluated. Eighty-six percent of the patients could be contacted for follow-up questioning. Thirty-nine percent had associated injuries. All Judet II, III and most of type IV fractures could be treated with the closed method. Ninety-eight percent showed an excellent or good result according to Morrey, 90% to Metaizeau score. The closed intramedullary pin reduction technique proved to be an innovative minimal invasive technique for displaced radial neck fractures by allowing anatomical reconstruction and stable treatment.

AIM We report about our experiences with the elastic stable intramedullary nailing (ESIN) of traumatic humeral shaft fractures in children and adolescents. METHOD Children with traumatic humerus shaft fractures who were treated by ESIN were included. All patients underwent clinical follow-up examinations. RESULTS 31 children (average age 11.4 years) with traumatic humeral shaft fractures could be included. There were 14 oblique, 12 transverse and 5 wedge fractures. In 5 cases the fracture was located in the proximal third, in 22 cases in the middle third and in 4 cases in the distal third. After an average period of 32 months a follow-up-examination with the Constant-Murley score was performed. All children attained 100 points and all patients could take part in sports activities like before the accident. 30 children and their parents were very satisfied with the treatment success and 1 patient was satisfied. The following complications were seen: 1 postoperative damage of the radial nerve in a patient with secondary fracture dislocation (complete remission), 1 skin irritation, 1 fracture dislocation with axial deviation, 1 secondary dislocation of the nails after a second accident and 1 secondary axial deviation. CONCLUSIONS Elastic stable intramedullary nailing (ESIN) of humerus shaft fractures has a low complication rate if attention is paid to biomechanical principles. The observed complications are based on mistakes concerning the indication or technical errors. The ESIN shows very good functional and cosmetic results. It allows an early functional and cast-free follow-up with a quick pain reduction. The ESIN of humeral shaft fractures is a minimally invasive, simple and well reproducible technique with a steep learning curve. Because of the excellent objective and subjective results, the operative stabilization of humerus shaft fractures with ESIN should be recommended to the patients and their parents.

AIM Determination of the femoral head position after closed or open reduction and application of a spica cast is possible by X-ray, MRI, CT or transinguinal ultrasound. In this study we compared the efficacy of transinguinal ultrasound and radiography. Further options with transinguinal ultrasound such as the determination of soft tissue and intraoperative possibilities are also described. MATERIAL AND METHODS In a first cohort of 25 patients with 33 affected hips ultrasound and radiography were compared. In a second cohort of 8 patients with 11 affected hips ultrasound and arthrography were compared. RESULTS 32 radiographs proved to be not useful for the precise determination of the femoral head position. In all ultrasound images the criteria described by van Douveren et al. could be identified. All ultrasound images in the study were useful and gave reliable information with regard to the femoral head position. CONCLUSION Consequently, standard radiographic documentation is no longer used as a standard in our clinic. MRI and CT are reserved for special cases. We recommend transinguinal ultrasound as a standard diagnostic method for determination of the femoral head position in hip spica casts. With a portable ultasound system, determination of the hip position using transinguinal ultrasound is immediately possible in the operating theatre.