While dissecting 88 lower limbs, a distal division of the sartorius muscle was detected in one of the specimens. The larger posteromedial portion was found to take a normal course to the so-called superficial pes anserinus. The thinner anterolateral portion attached to the medial meniscus anteromedially. The smaller anterolateral part approached the medial meniscus anteromedially, pushing the synovial membrane into the joint. Its meniscal attachment ensures that the medial meniscus is stabilized in its primary position during bending and external rotation in the knee joint, thus preventing its herniation or injury during sudden extension. The accessory part of the sartorius muscle thus acts as a protector of the medial meniscus.

A cementless total hip system of modular design is presented. The design of the stem provides for a firm seating on the cortical bone over a large area. Therefore primarily stable fixation is accomplished. The stem in seven different sizes is made of hot forged Ti-6Al-4V Protasul-64 WF alloy of high corrosion fatigue strength. The Biolox ceramic ball with three different neck lengths is connected to the high strength stem by means of a special selflocking conical spigot with a structured surface. The ceramic ball is combined with a polyethylene screw socket in four different sizes, designed by Endler and anchored in the acetabulum without acrylic cement. This hip prosthesis system has proved itself in clinical application since 1979.

In patients with malignant tumors in the region of the shoulder, radical resection can avoid amputation in most instances. To improve the function of the arm, endoprosthetic replacement of the defect is desirable.

Construction principles, mechanical and animal experiments with various types of endoprostheses consisting of dense alumina are reported as well as the first results in man. A stable implantation of this biocompatible material is possible, if the primary attachment by means of special construction features and subtile operation technique is ensured. The definite dixation of the implant is provided by the ingrowth of newly formed bone tissue in circular running indentations. Therefore the use of bone cement, one of the critical points in replacement surgery, can be avoided. In tumor surgery the replacement of the proximal humerus by a ceramic prosthesis has proven to be successful. Equally satisfactory results could be achieved in the therapy of osteoarthritis of the hip with a metal-ceramic composite endoprosthesis.

Dense, highly pure A12O3 ceramic not only shows excellent wear resistance and tissue biocompatibility, but also has sufficient mechanical strength for loaded endoprostheses. The necessary diameter size of the material to sustain adequate shear stresses can be achieved, if the endoprosthesis is attached extracortically to the conically truncated long bone according to the principle of the conical sleeve. Extracortical attachment of the endoprosthesis causes minor nutritive damage since long bones derive their vascular supply mainly from the medullary cavity. In this way a primary stable and loadable connection is established, which is a prerequisite for permanent anchorage of the implant through new bone formation. After experiments in 12 dogs bioceramic endoprostheses were implanted in a total of 40 human patients using this technique of extracortical attachment (12 hip joints, 24 proximal humeri, 4 special constructions). Thirty-six of these implants were stable after observation periods ranging from one to 49 months. A stable anchorage of the prostheses to the pre-existing bone through new bone formation could be demonstrated histologically. The above preliminary results show that bioceramic endoprostheses can be "incorporated" in the skeleton and possibly also withstand the functional stresses.

Es wird über eine neue, ohne Knochenzement zu implantierende Endoprothese zur Therapie der Coxarthrose berichtet. Diese Prothese besteht aus einer Keramikpfanne, einem Titaniumschaft, der mit einer Keramikschichte (Al2O3) überzogen ist. Das proximale Ende des Schaftes trägt einen Konus, auf den eine Keramikkugel aufgesetzt wird, die mit der Pfanne artikuliert. Neben den Konstruktionsprinzipien werden Implantationstechnik und erste klinische Erfahrungen mitgeteilt.

Anhand verschiedener Tumore sowie tumorähnlicher Erkrankungen des Bewegungsapparates wird der Wert des Ultraschalles als Zusatzuntersuchung zu Nativröntgen und Angiographie geprüft. Es ergibt sich, daß die Ultraschallechotomogramme in vielen Fällen eine Hilfe darstellen, die hauptsächlich in der besseren präoperativen Größendarstellung und Topographie, sowie in einigen Fällen auch in der Aufklärung von Tumoraufbau und Struktur beruht. Aus diesem Grunde kann die Methode für den Operateur eine wertvolle Information liefern. Die Feststellung von Weichteiltumoren bei negativen Nativröntgen und negativer Angiographie ist in einigen Fällen gut möglich. Bei der Rezidivsuche kann der Ultraschall ebenfalls von Bedeutung sein.

This paper describes the design principles of a new endoprosthesis made of dense aluminum oxide (A12O3) and implanted without bone cement. Mechanical tests and animal experiments have proved the sufficient mechanical strength of the bone-prosthesis connection as well as the biocompatibility of the material. So far, 12 tumor patients selected according to strict indication criteria have been operated on. Both the clinical-radiologic and the first histological findings available are encouraging. Special reference is made to the first fully ceramic total hip joint endoprostheses implanted in a human without bone cement.

Die Konstruktionsmerkmale von Endoprothesen aus Al2O3 werden vorgestellt. Die Befestigung am langen Röhrenknochen erfolgt mittels einer Kegelhülsenverbindung. Diese Prothesen-Knochenverbindung wurde mechanischen Festigkeitsprüfungen unterworfen and im Tierexperiment überprüft. Die Ergebnisse ermutigten zur klinischen Anwendung am Tumorpatienten, die an Hand verschiedener Fälle demonstriert wird. Auf die Möglichkeit, auch große Defekte zu überbrücken, wird hingewiesen.