Rudolf Lemperg

Fracture of the femoral neck. II. Relative importance of primary vascular damage and surgical procedure for the development of necrosis of the femoral head.

The opinion is widely held that interruption of the arterial flow through the retinacular arteries to the femoral head is the main cause of avascular necrosis after fracture of the neck. In this study the state of the vascular supply to the femoral head was assessed--prior to osteosynthesis--by means of intramedullary pressure measurements in the femoral head and neck in 72 patients with medial neck fractures. The patients were followed 2 or 3 years or until avascular necrosis became evident. The relative importance of primary avascularity and surgical technique for the development of necrosis suggests that damage to the retinacular arteries may not be the single decisive factor in the pathogenesis of femoral head necrosis. Proper fracture reduction with extensive contact between the cancellous bone surfaces and stable fixation seemed to be more important, probably because they offer the best possibilities for re-establishment of transosseous blood flow across the fracture site.

The glycosaminoglycans of human articular cartilage: concentration and distribution in different layers in the adult individual.

The articular cartilage from morphologically normal femoral heads from 7 humans, aged 50-85 years, was sectioned parallel to the surface firstly at 40 micron thickness and then serially at 200 micron thickness to the cartilage-bone junction. Pooled sections from separate layers were used for analysis of the glycosaminoglycans by Cetylpyridinum chloride and ECTEOLA-cellulose microcolumns. The total concentration of glycosaminoglycans per dry weight tissue showed an increase with distance from the articular surface. The increase was shown to be due, principally, to keratan sulphate, while the levels of hyaluronic acid and chondroitin sulphate showed a proportional decrease with depth. The 40 micron thick superficial layer contained a considerably lower concentration of both keratan sulphate and chondroitin sulphate than the rest of the cartilage. These superficial layer glycosaminoglycans, and particularly chondroitin sulphate, showed a more polydisperse distribution according to molecular weight/charge density than the corresponding glycosaminoglycans of the more deeply situated layers. In view of findings on bovine articular cartilage of different age-classes reported previously, these features of the superficial layer appear to represent the normal biochemical structure.

Transplantation of autologous costal cartilage to an osteochondral defect on the femoral head@@@Transplantation von autologem Rippenknorpel in einen osteochondralen Defekt auf dem Hftgelenkskopf: Histological and autoradiographical studies in adult rabbits after administration of 35S-sulphate and 3H-thymidine@@@Eine histologische und autoradiographische Studie nach Zufuhr von 35S-Sulfat und 3H-Thymidine, ausgefhrt an erwachsenen Kaninchen

Am Hüftgelenkskopf von erwachsenen Kaninchen wurde ein 3×4×3 mm großer osteochondraler Defekt geschaffen. In diesen wurden (A) autologer Rippenknorpel, welcher zuerst während 4–5 Wochen intramuskulär implantiert war (18 Tiere), und (B) frischer autologer Rippenknorpel (17 Tiere), transplantiert. An 7 verschiedenen Beobachtungszeitpunkten zwischen 1–46 Wochen wurden die Tiere getötet. Der Hüftgelenkskopf wurde in 35S-Sulfat oder 3H-Thymidine in vitro inkubiert und histologisch und autoradiografisch untersucht. In 34 der 35 Präparate beider Versuchsgruppen und an allen Beobachtungszeitpunkten lag das Transplantationsgebiet im gleichen Niveau wie der übrige Gelenkknorpel. Die histologische und autoradiographische Untersuchung zeigte eine Vereinigung des Transplantatknorpels mit dem Gelenkknorpel durch jungen, hyalinen Knorpel, mit hohem 35S-Sulfat-Einbau, an allen Beobachtungszeiten von 4 Wochen aufwärts, in 13 der 14 Fälle der Gruppe A und in 12 der 13 Fälle in Gruppe B. Nach Versuchszeiten von 1 und 2 Wochen wurde junger, reifer Knorpel zwischen Transplantat und Gelenkknorpel in 2 der 4 Fälle der Gruppe A, aber in keinem der 4 Fälle in Gruppe B beobachtet. Unreifer Knorpel kam in 3 der 4 Fälle in Gruppe A und in 1 der 4 der Gruppe B vor. Die Gelenkfläche des Transplantationsgebietes bestand zum überwiegenden Teil aus jungem, reifen Knorpel in 16 der 18 Fälle der Gruppe A (an allen Beobachtungszeitpunkten) und in 11 der 17 Fälle der Gruppe B (an allen Beobachtungszeiten von 4 Wochen aufwärts). Dieser junge Knorpel zeigte hohe 35S-Sulfat-Aufnahme und enthielt 3H-Thymidin-markierte Chondrocyten. In beiden Untersuchungsgruppen zeigten, nach Versuchszeiten von 8 Wochen aufwärts, die Chondrocyten dieses jungen Knorpels eine Tendenz, sich in Reihen senkrecht zur Gelenkfläche anzuordnen. Die Schichten nächst der Gelenkfläche zeigten eine mehr tangentiale Zellanordnung. Die Transplantate trugen wahrscheinlich aktiv zur Wiederherstellung der Gelenkfläche des Defektgebietes und zur knorpeligen Vereinigung von Transplantat und Gelenkknorpel mit lebendem, hyalinem Knorpel bei. Auch örtliches Gewebe, aus dem subchondralen Knochengebiet, dürfte bis zu einem gewissen Teil zu dieser Wiederherstellung beigetragen haben. (A) Autologous costal cartilage which had first been implanted intramuscularly for 4–5 weeks (18 animals) and (B) fresh autologous costal cartilage (17 animals) were transplanted to an osteochondral defect, measuring 3×4×3 mm, on the femoral head in adult rabbits. After 7 different observation times between 1 and 46 weeks the animals were killed. The femoral head was incubated in 35S-sulphate or 3H-thymidine in vitro and examined histologically and autoradiographically. In 34 of the 35 preparations from the two experimental groups, and at all observation times, the transplant area lay at a level with the remaining articular surface. Both histological and autoradiographical examination revealed union of the transplant with the articular cartilage via young hyaline cartilage, with a high 35S-sulphate uptake, at observation times from 4 weeks onwards, in 13 out of 14 cases in group A and in 12 out of 13 cases in group B. At observation times of 1 and 2 weeks, young mature cartilage was found between the transplant and articular cartilage in 2 out of 4 cases in group A and in no cases in group B. Immature cartilage occurred in 3 out 4 cases in group A and in 1 out of 4 in group B. The articular surface in the transplant area consisted to the greatest part of young mature cartilage in 16 of the 18 cases in group A (all observation times) and in 11 of the 17 cases in group B (at all observation times from 4 weeks onwards). This young cartilage showed a high 35S-sulphate uptake and contained 3H-thymidine labelled chondrocytes. At observation times from 8 weeks onwards the chondrocytes in this young cartilage in both experimental groups showed a tendency to a columnar arrangement oriented at right angles to the articular surface, and the layer of cells nearest to the articular surface were arranged tangentially to the joint cavity. The transplants probably contributed actively to the cartilaginous union between the transplant and the articular cartilage and to restitution of the articular surface in the defect area with viable hyaline cartilage. Local tissue from the subchondral bone area also appeared to have contributed to some extent.

Transplantation of autologous costal cartilage to an osteochondral defect on the femoral head

(A) Autologous costal cartilage which had first been implanted intramuscularly for 4–5 weeks (18 animals) and (B) fresh autologous costal cartilage (17 animals) were transplanted to an osteochondral defect, measuring 3×4×3 mm, on the femoral head in adult rabbits. After 7 different observation times between 1 and 46 weeks the animals were killed. The femoral head was incubated in 35S-sulphate or 3H-thymidine in vitro and examined histologically and autoradiographically.

The glycosaminoglycans of human articular cartilage: molecular weight distribution of chondroitin sulphate in different layers in the adult individual.

Articular cartilage from 3 human femoral heads was sectioned serially, at 200 micron thickness, parallel to the articular surface. The morphologically normal cartilage was compared with superficially fibrillated cartilage. Sections from 5 or 6 defined layers representing the cartilage bulk were pooled and the sodium salt of chondroitin sulphate was isolated from each layer. The molecular weight distribution of the chondroitin sulphate was determined by either Sephadex G-200 or Sephacryl S-200 gel chromatography. For the normal articular cartilage from the 3 individuals a reduction of the average molecular weight of the chondroitin sulphate from the articular surface to the cartilage-bone junction was observed. In the superfically fibrillated cartilage superficial layer chondroitin sulphate had a smaller average molecular weight than the corresponding normal cartilage of the same femoral head.