Are patients with hip fractures more osteoporotic? Review of the evidence.

This report critically reviews 15 case-control studies that disagree about whether patients who fracture their hip are significantly more osteoporotic than persons of similar age who do not. The most rigorously designed studies observed less bone mass in the hips of patients with fractures than in the hips of control subjects, but the differences were usually small and overlapping. Measurements at other sites in the skeleton did not consistently find differences. Those studies that protected against ascertainment bias generally found smaller differences than studies that did not. Patients with hip fractures do not appear to be distinctly more osteoporotic than persons of similar age. Therefore, factors besides bone mass, such as a tendency to fall, may be important determinants of which elderly persons will have fractures; thus, measurements of bone mass might not be a reliable way to identify those at greatest risk of hip fracture.

A paramagnetic agent causing ochronotic arthropathy.

Magnetic resonance imaging (MRI) identified a paramagnetic substance in the hyaline cartilage of the hips and knees in a patient with ochronosis. Chemical studies characterized the paramagnetic agent as melanin. The free radicals contained in melanin were shown to initiate cytotoxicity. The loss of cartilage in ochronotic arthropathy now can be explained at the electron level using the superoxide theory of oxygen toxicity. Inappropriate metabolism of oxygen also may explain early cartilage degeneration in hemochromatosis, hemosiderosis, and Wilson's disease.

Transient synovitis of the hip in the child: increased levels of proteoglycan fragments in joint fluid.

The levels of proteoglycan antigen were measured in joint aspirates from the hip of children with transient synovitis, septic arthritis, Legg-Calvé-Perthes' disease and congenital and traumatic dislocation. Significantly increased levels were found in children with transient synovitis and septic arthritis as compared with other conditions. We propose that the proteoglycan antigens in the joint fluid were released from the articular cartilage in a partially degraded form as a result of an increased rate of proteolytic degradation. In transient synovitis, the source of proteolytic activity may be chondrocytes activated by factors released by synovial cells. The release of joint proteoglycan may cause a temporary increase in deformability of the hip cartilage of the child that could be an important pathogenetic mechanism in some of the sequelae of these diseases.

[Additional information regarding periarticular ossifications after total hip replacement (author's transl)]. / Beitrag zur Frage periartikulärer Verkalkungen nach totalendoprothetischem Hüftgelenksersatz

Residual monomer originating from acrylic bone cement is not the origin of periarticular calcifications after hip joint replacement. This has been demonstrated by gaschromatografic detection of monomeric methylmethacrylate in the liquid of the joint space. Up to 200 microng/ml monomeric MMA could be demonstrated in the first days after the operation only. The concentration of residual monomeric MMA in the bone cement is 1% to 4%. It is deminished time dependently by diffusion of the molecule in the surrounding tissue. All determined concentrations of monomeric MMA in the joint liquid are below the toxic range for tissue demage.

Histochemical and histophysical detection of wear products resulting from prostheses.

The authors determined the wear products in tissues following hip prostheses implantations in 40 cases. The interval between prostheses implantation and histochemical examinations varied from 3 weeks to 15 years. The authors found that on the inner layer of the neighbouring joint capsule immediate to the implant a metal-protein layer developed and cobalt, chrom, nickel particles were demonstrated later in the connective and scar tissues as well. In the connective and fat tissues around the hip prostheses (from 4 cm) cobalt and chrom, in the regional lymph nodes cobalt, chrom nickel and in some cases manganese particles were found. Bone cement and plastic materials were found in the joint capsule, in the bone marrow of the distal part of the femur, but they were not present in the lymph nodes.

Amyloidosis of the joints: evidence that human hip capsules have a unique predisposition for amyloid of the senile systemic type.

Amyloid-containing tissues were sampled from 19 capsules and 10 cartilages from hip, knee and sternoclavicular joints of 16 elderly patients. Heart ventricles from 3 of these patients were also studied. Histochemistry and immunofluorescence were performed and amyloid fibrils extracted from one hip capsule. The results indicate that 9 of 13 hip capsules contained prealbumin-like amyloid fibril protein ASc1, a finding characteristic of senile systemic amyloidosis. The amyloid of 16 out of 17 other joint structures showed no reaction with anti-ASc1 or antisera to 3 other systemic forms of amyloid, indicating that they represent localized forms of amyloid.

Proteoglycans of articular cartilage in Mseleni joint disease.

Femoral heads were resected from patients with Mseleni joint disease, and cartilage present in 'islands' on the articulating surfaces and over marginal osteophytes was removed for study. Some specimens were grown in short-term organ culture and labelled with sulphur-35. Proteoglycans present in the tissue, and newly synthesised macromolecules were extracted, purified and assessed. The results indicated that very few of the proteoglycans present or synthesised during culture were capable of aggregation with hyaluronate and that the average size of the macromolecules was smaller than normal. In addition a large proportion of the proteoglycans were very small in size and were thought to resemble a molecule found in immature articular cartilage. The response to degenerative disease was unusual and may be peculiar to the Mseleni condition.

Microdeposition of amyloid in the joints.

The distribution of amyloid in various organs, including the hip and the sternoclavicular joints, was systemically investigated in a prospective necropsy study of 91 unselected individuals whose median age was 70 years. The overall incidence of amyloid microdeposits in both joints was 56%. Their presence correlated significantly with age only. The deposition began earlier in the sternoclavicular joint, where the fibrocartilaginous disc was almost exclusively affected. The myocardium was the next most frequently affected organ, with an incidence of 12.2%. Minor amyloidosis of the articular tissues had no significant clinical counterpart, neither was it associated with any particular disease. It seemingly represents a localised and isolated degenerative phenomenon, whose morphological aspects invite speculation about the pathogenic role of long-lasting mechanical stress.

[Microdurimetric and biochemical study of human articular cartilage. Comparison of different joints]. / Etude microdurimétrique et biochimique du cartilage articulaire humain. Comparaisons de diverses jointures.

The micro-hardness and the density of fixed negative charges in cartilage of the shoulders, hips and knees of 6 subjects were studied. These two parameters were narrowly correlated. The resistance and proteoglycan concentration of the cartilage of the femoral head were greater than those of the knee and of the shoulder. They did not vary on each side. There is a significant correlation between the hardness of the cartilage of the femoral head and of the external femoral condyle. The histologically normal cartilage of the femoral head in arthrosis is at the lower limit of control values for hardness.

Soft tissue collagen in congenital dislocation of the hip. Biochemical studies of the ligamentum teres of the femur and the hip joint capsule.

Collagens of the ligamentum teres of the femur and the hip joint capsule of 14 patients with congenital dislocation of the hip (CDH) were studied biochemically. Collagen was a major component of these tissues. Solubility of collagen was reversely related to age except in two cases. Collagen of both ligamentum teres of the femur and hip joint capsule was composed of type I, III and V collagens except in three cases. In these three cases with nevus or general joint laxity, two additional collagenous components were also found. The ratios of type III collagen to type I collagen were increased in CDH except in one case with short stature. These abnormalities of collagen metabolism could be the underlying cause of CDH and other clinical symptoms in these patients.

[Tissue burden with exogenous trace elements caused by roentgen contrast media in bone cements]. / Gewebebelastung mit körperfremden Spurenelementen durch Röntgenkontrastmittel der Knochenzemente.

In 44 patients undergoing a change of total hip prosthesis, made of Co-Cr alloy and at one point with a Refobacin-Palacos chain we analyzed samples of the hip joint capsule and fascia lata. Using Instrumental Neutron Activation Analysis (INAA) up to 18 elements were analyzed. The findings demonstrate that the tissues in the surroundings as well as in direct contact with the total hip prosthesis are burdened by corrosion products of the alloy and by decomposition of the bone cement. The decomposition of bone cement can be shown in the extraordinary high concentration of Barium, Zirconium and Hafnium which are added to Bone Cements as X-ray contrast. Microscopic findings at the same time complete and confirm the trace element analyses.

Contents and compositions of glycosaminoglycans in different sites of the human hip joint cartilage.

The distribution of glycosaminoglycans (GAGs) in different functional regions (weight-bearing and nonweight-bearing portions) of the human hip joint cartilage was studied. The results obtained were as follows: (1) Weight-bearing cartilage contains larger amounts of GAGs than nonweight-bearing, cartilage. (2) Weight-bearing cartilage contains keratan sulphate in higher ratio to chondroitin sulphate than nonweight-bearing cartilage. (3) The differences in content and composition of GAGs between the weight-bearing and nonweight-bearing portions are more pronounced in the femoral head than in the acetabulum. The preliminary analyses showed that the chondroitin sulphate from the acetabular cartilage contained exclusively 6-sulphated disaccharide units and there was some heterogeneity in keratan sulphate.

[3H]proline incorporation in vivo in capsular tissues and menisci during the development of osteoarthritis. An experimental study with rabbits.

In an effort to clarify factors related to the pathogenesis of experimental osteoarthritis, biochemical alterations were studied in articular soft tissues of adult rabbits through the immobilization of the knee of the hind leg in extension for 3, 7, 11, 18, 35 or 56 days. The medial collateral ligament and medial meniscus of the knee, as well as the joint capsule of the hip, were analysed. Total protein synthesis (measured by [3H]proline incorporation) increased in the immobilized legs in all of the tissues examined. The collagen synthesis rate (estimated by specific radioactivity of hydroxyproline) in the medial collateral ligament was enhanced, whereas the collagen content (measured as hydroxyproline concentration) of the tissue declined temporarily. This observation suggests that the collagen degradation rate transiently exceeds that of collagen synthesis. The results indicate that distinct biochemical alterations occur in the periarticular tissues during the early phases of immobilization-induced osteoarthritis. It is of interest that biochemical changes similar to those of the immobilized leg were seen, to a lesser extent, in the structures of the contralateral nonimmobilized leg.