Anatomie,Biomechanik und Klassifikation der Sprunggelenkfrakturen

Functional integrity of the ankle joint is guaranteed by the shape of the joint surfaces, the capsuloligamentous attachments, and the muscles crossing the ankle. Assessment of ankle joint injuries therefore must focus not only on the fracture site and morphology but also on ligamentous ruptures or bony avulsions of the collateral and syndesmotic ligaments. Important criteria for stability and therefore indication for surgery are fibular position and shortening, competence of the medial structures, and the tibiofibular syndesmosis. The genetic Lauge-Hansen classification system facilitates understanding the mechanism of injury and closed reduction as well as determining stability and indications for surgery in more than 95% of ankle fractures. The Danis-Weber classification must be supplemented by the AO classification subgroups in order to allow assessment of the stability. Ankle fractures in children are classified according to their position with regard to the epiphyseal plate, except transitional fractures in adolescents that warrant three-dimensional assessment.     

Anatomie und Biomechanik des Patellofemoralgelenks

The patellofemoral joint constitutes a complex anatomical and functional entity. The tensile force of the quadriceps femoris muscle is transmitted through the patella and patellar ligament onto the tibial tuberosity. This particular three-dimensional arrangement increases the torsional moment acting on the knee joint. Dynamic alignment of the patella is determined by trochlear geometry and is supported by active muscular and passive connective tissue stabilizers. In addition to the retinaculum of the patella, the medial patellofemoral ligament is attracting increasing clinical attention. Multidirectional motion of the patella is closely connected to retropatellar pressure distribution which can be modulated by moving the patellar ligament insertion. Implantation of a knee endoprosthesis changes the joint surface geometry and consequently patella kinematics and retropatellar pressure distribution. Finite element analysis provides the possibility to assess retropatellar pressure distribution before and after implantation of prostheses.     

Anatomie und Biomechanik des Beckens

Voraussetzung einer erfolgreichen Behandlung einer Beckenverletzung ist das anatomische und biomechanische Verst?ndnis des physiologischen Kraftflusses vom Schenkelhals über die Gelenkpfanne zum Sakroiliakalgelenk. Eine wichtige Tr?gerfunktion haben nicht nur der Beckenknochen, sondern auch die ligament?ren Strukturen, besonders die Ligg. sacroiliaca dorsalia. Für die ?Stabilit?tsbeurteilung und Klassifikation der Verletzungsmuster hat sich die Einteilung nach Pennal et al. bew?hrt, die die Richtung der Krafteinwirkung berücksichtigt. Es lassen sich 3 Grundformen unterscheiden: die a.-p.-Kompression, die laterale Kompression und die vertikale Abscherung. Je nach Ausma? des Verletzungsmusters lassen sich Untertypen unterscheiden, die konservativ behandelt werden k?nnen oder eine operative Therapie erfordern. Die Biomechanik und die Verletzungsmuster werden anschaulich und reichlich illustriert beschrieben.      

Anatomie,Biomechanik und Klassifikation der Schultergelenkverletzung

Movement of the shoulder joint is characterized by a complex interaction between three main joints and two subsidiary joints. The wide range of motion of this ball-and-socket joint is only possible because the socket is relatively small, the articulation surface of the glenoid being only one quarter the size of the humeral head. The kinematics of the glenohumeral joint is stabilized and controlled through the interaction of several structures: passively by bone and ligaments and actively by muscles. The ligaments of the glenohumeral joint with their mechanoreceptors have a particularly prominent role in controlling the forces that stabilize the joint. The muscles of the rotator cuff act both as stabilizer and as driver for movement, depending on the position of the arm, and are an integral element of the overall neuromuscular control system. The classifications of instabilities and lesions of the rotator cuff used in modern therapeutic practice have been adapted to the treatment options. The classification presented in this paper is based on the basic pathophysiology and clinical prognosis of the condition.     

Anatomie und Biomechanik des Kahnbeins

The scaphoid is biomechanically and clinically of great importance for function of the wrist. In the literature, its anatomy and biomechanics are clearly underrepresented as well as underestimated. In the following review the scaphoid will be presented in more detail, according to recent information and findings. Not only will the origin of the name and the history of previous names, such as cotyloid or navicular, be introduced, but also for the first time in medical literature the significant phylogeny and ontogeny of the scaphoid will be shown. Moreover, the clinically very important blood supply, the ligaments of the scaphoid and relevant biomechanical details will be described.     

Anatomie,Biomechanik und Pathomechanik des Pilon tibiale

The tibial pilon is the broad joint-bearing portion of the distal tibia. The concave horizontal joint surface facing the talar dome is also referred to as tibial plafond. Fractures of the tibial pilon with joint involvement usually result from a considerable axial impact. The prognosis is regarded as critical because of the primary cartilage damage. The treatment of pilon fractures belongs to the challenges in trauma surgery and requires profound knowledge of the anatomy, a detailed analysis of the injury, and careful surgical planning. The following article gives an overview on anatomy, biomechanics and pathomechanics of the tibial pilon as well as classification and surgical planning of pilon fractures.     

Anatomie und Biomechanik des oberen Sprunggelenks

The ankle joint as a component within the construction of the foot must be seen as a compromise between the static and dynamic demands made upon it. In this article the structure and function of the ankle joint are described with special reference to the formation of morphological parameters such as the distribution of subchondral mineralization, cartilage thickness, subarticular cancellous bone and mechanical properties. These parameters could be seen as a biological reflection of the individual mechanical conditions.     

38. Anatomie und Biomechanik des Kniegelenksmeniscus

Zusammenfassung Die Menisci vergrössern nicht nur die Tragfläche des Kniegelenks im Vergleich zur reinen Kontaktfläche zwischen Femurkondylen und Tibiaplateau auf das Doppelte, sondern sie erweitern auch den Spielraum der Gelenksresultierenden beträchtlich. Folglich können die das Gleichgewicht herstellenden Muskeln ökonomischer eingesetzt und die Kreuzbänder entlastet werden. Die Menisci bestehen aus derben Kollagenfaserbündeln, die — an die mechanische Beanspruchung angepasst — zirkulär orientiert sind. Das Spaltlinienbild zeigt jedoch eine kompliziertere Struktur.     

Anatomie und Biomechanik des Kapsel-Bandapparates am Kniegelenk

The anatomic characteristics of the different parts of the knee joint, which are important for the function, are outlined. The passive stabilizers are discussed with special emphasis upon the dorsal ligaments of the capsule. Anatomy and functions of the active stabilizers of the joint are described. In the second part of the paper the complicated mechanism of the knee joint is discussed. It follows the laws of kinetics and can be therefore tested and reproduced.     

Anatomie, Biomechanik und Therapie der Verletzungen des hinteren Kreuzbands

Injury of the posterior cruciate ligament (PCL) is still a serious challenge to the surgeon. IN contrast to the situation with surgical treatment of the anterior cruciate ligament (ACL), there is no gold standard in therapy. Conservative treatment is described as the treatment of choice, but so are early repair and primary and secondary reconstruction. Even with MRI, the diagnosis of many such injuries is missed or delayed, and most studies involve only a small number of cases. This means that comparison of the different surgical techniques used is not strictly valid. The excellent vascularisation allows conservative treatment as well as refixation of the ligaments with an additional augmentation. The most difficult problems arise from the anatomy with different fibre bundles, so that instead of a point, there are only zones of isometry in the femoral attachment; use of the patellar, quadriceps, or semitendinosus/gracilis tendon is preferred for reconstruction of the PCL in a femoral single- or double-bundle technique.     

Die Biomechanik von Schrauben, Draht- und Kabelcerclagen

In contrast to fracture fixation, when performing an osteotomy the surgeon is able to plan preoperatively. The resulting fixation and compression of the bone fragments are the most important points. A stable osteosynthesis should prevent dislocation of bone fragments and improve bone healing. Beside plates, cerclages can be used for tension band or diaphysis bone fixation. Moreover, cortical or cancellous screws can be used for osteotomy fixation. This work describes biomechanical principles for fixation after an osteotomy with cerclages and cortical or cancellous screws. It also summarizes the materials and geometries used, as well as their influence on the stability of the osteosynthesis.     

Klinische Anatomie und Biomechanik des Sprunggelenkes unter besonderer Berücksichtigung der Endoprothetik

Zusammenfassung Die Articulatio talocruralis (oberes Sprunggelenk) erlaubt dem Fuß die elementaren Bewegungen der plantaren Flexion und der dorsalen Extension. Die Morphologie des Gelenks ist diesen Hauptbewegungen angepasst. Es ist allerdings kein reines Scharniergelenk, sondern es treten zusätzliche Rotations- und Translationsbewegungen auf. Das distale Fibulaende zeigt individuell unterschiedliche Kompensationswegungen.Gelenkkräfte werden vornehmlich über die distale Tibiagelenkfläche und die Facies superior der Trochlea tali übertragen; allerdings sind die laterale fibulotalare und die mediale tibiotalare Artikulation mitbeteiligt. Über den Talus werden Kräfte in den Rückund in den Vorfuß geleitet, er dient als alleiniger Kraftverteiler.Die prothetische Versorgung des oberen Sprunggelenks muss den kinematischen und kinetischen Anforderungen Rechnung tragen, d. h. Drehen und Gleiten müssen möglich bleiben und zur Kraftübertragung sollten die Kontaktflächen zwischen den Prothesenkomponenten selbst und zwischen Prothesenelement und Knochenlager groß sein. Die Verankerung des talaren Prothesenteils sollte die arteriellen intraossären Gefäße des Sprungbeins nicht wesentlich beeinträchtigen, da ansonsten die Gefahr der Knochennekrose besteht.     

Biomechanik von Knorpel-Tissue-Engineering-Konstrukten

Specific biomechanical properties represent important quality markers of cartilage tissue engineering (TE) constructs. The aim of the study was to identify a sensitive biomechanical test to assess mechanical properties of cartilage TE constructs. Biomechanical testing of in vitro cultivated constructs following the very low rubber hardness (VLRH) principle illustrated significant differences between constructs cultured under chondrogenic conditions over various periods of time. An increase in proteoglycan and collagen type II deposition corresponded to increasing VLRH hardness values. Although a decrease in proteoglycan was detected after ectopic implantation of constructs into SCID mice, no reduction in biomechanical hardness values was observed. A functional estimation of TE constructs requires determination of biomechanical and biochemical parameters as quality features.     

Unfallanalyse und Biomechanik

The number of claims linked to whiplash injuries is steadily increasing in most European countries. After minor accidents the question often arises as to whether the occupant could really have been injured. The technical expert may calculate the biomechanical stress imposed on the occupants by the impact from the evidence gathered after the accident. Based on this data the medical expert is able to judge whether this stress was sufficient to produce the injury claimed. The threshold of biomechanical loading necessary for spinal injuries will be deduced from a technical perspective. With the help of examples, the steps required to preserve evidence will be explained.     

Biomechanik und Biochemie der Gelenkfrakturen

Ohne ZusammenfassungMit 6 Abbildungen     

Design und Biomechanik inverser Schulterprothesen

Reverse shoulder arthroplasty has developed from a salvage procedure for a small group of selected patients with pseudoparalysis to a standard procedure for a variety of shoulder diseases associated with rotator cuff insufficiency. By inversing the joint surfaces the humeral head can be stabilized on the glenoid despite an insufficient rotator cuff. A normal shoulder function, however, cannot be expected after such a procedure. Reverse prostheses medialize the centre of rotation and distalize the humerus. This has an influence on the range of motion, the lever arms, the forces and the stability of the reconstructed joints. The currently used prosthesis models differ in many parameters. The following article describes the most important features and biomechanics of reverse prostheses.