[Determination of the elasticity of the femoral cortex of Adam's arc in patients with osteoarthritis]. / Ermittlung der Bruchfestigkeit der Femurkortikalis am Adam'schen Bogen bei Patienten mit Osteoarthrose.

In this study, the compressive strength, the compressive force as well as cortical thickness of prismatic specimens from Adam's arc of the femur were determined in patients with osteoarthrosis. Correlations were evaluated between the cortical bone parameters, which depend on age and sex. Supported by histomorphometric data of cancellous bone, the great variability of mechanical properties revealed the variable osteological status prior to implantation of hip endoprostheses. Its eventual consequences for alloarthroplastic surgery had been discussed.

Quantitative study of articular cartilage and subchondral bone remodeling in the knee joint of dogs after strenuous running training.

All tissues of the joint are affected in some way in osteoarthritis because the joint is an interactively functioning unit. Our goal was to investigate the combined responses of articular cartilage and subchondral bone to altered loading conditions to improve our understanding of the physiology of these two components and, ultimately, the pathophysiology of osteoarthritis. A group of 20 female beagle dogs were divided pairwise into runners (n = 10) and controls (n = 10). The running training on a treadmill started at the age of 15 weeks, and during the following 40 weeks the running distance was gradually increased to 40 km/day with a 15 degree uphill inclination. With this daily running distance the beagles ran another 15 weeks. The samples for histology were taken from 11 different locations of the knee joint. Subchondral bone and articular cartilage histomorphometry was carried out in three different regions of the specimens (central, middle, and peripheral regions) using an image-analyzing system and an eyepiece graticule. In all regions of the articular cartilage, both the uncalcified and calcified cartilage showed slightly increased thickness in the runner dogs. The change was more evident in the peripheral and the central areas. The thickness of the subchondral bone plate tended to be higher in runners, too. Bone histomorphometric parameters showed significant signs of increased remodeling. The most notable change was the enlargement of the bone formation surface. The most intense remodeling was usually observed either centrally or peripherally in the articular surface. The strongest increase in trabecular bone volume and thickness of the cartilage was recorded in the femoropatellar area.(ABSTRACT TRUNCATED AT 250 WORDS)

Osteologic standardization of human coxarthrosis using histomorphometry and its relevance for HIP alloarthroplasty.

Using bone histomorphometry, in this study the osteologic status of 107 patients with coxarthrosis and femoral neck fracture [FNF] was assessed and compared with bone parameters from patients revised for aseptic loosening. Bone biopsies of the acetabulum and the proximal femur from patients with primary coxarthrosis [pCoxA] (69), dysplastic coxarthrosis [CDH] (19), rheumatoid arthritis [RA] (9), femoral head necrosis [FHN] (8), femoral neck fracture [FNF] (4) and aseptic loosening (12) were taken during hip alloarthroplastic surgery, prepared undecalcified and analysed using histomorphometry (according to MERZ). In pCoxA the following average figures of bone parameters of the acetabular biopsy were determined: trabecular bone volume (TBV) 39.6%, osteoid volume (OV) 3.9%, active osteoblastic surface (AOS) 6.5%, osteoclastic resorption surface (ORS) 2.4%, osteoid surface (OS) 17.4% and resorption surface (RS) 7.0%. As average figures of the femoral biopsy in pCoxA were assessed: TBV = 17.2%, OV = 1.3%, AOS = 0.9%, ORS = 0.4%, OS = 6.5% and RS = 2.5%. These data were compared with bone parameters of secondary coxarthrosis, osteoporosis (FNF) and aseptic loosening. Based on the study of Oettmeier et al. on femoral heads (Skel Radiol 18: 165-174, 1989), the investigated groups were subdivided into three osteologic types of the hip. The osteopenic type was found in 10% of pCoxA, 43% of RA and 28% of CDH. The hyperostotic type, predominantly occurring in males, was mostly demarcated in FHN (38%) and pCoxA (12%). The results demonstrate the individual osteologic status of patients before hip alloarthroplasty. This could influence planning of the operation and the bone-implant interface as well as long-term prognosis of artificial joints.

Analyses of the tidemark on human femoral heads. I. Histochemical, ultrastructural and microanalytic characterization of the normal structure of the intercartilaginous junction.

The tidemark as a boundary between non-calcified and calcified articular cartilage has a complicated structure and fulfils various physiological functions. 25 human femoral heads from healthy joints were examined. In non-decalcified preparations three structural components of the tidemark were demarcated: (1) the PAS-positive, proteoglycan-containing tidemark line adjacent to the basal cartilage, (2) the sublinear light-coloured zone and (3) the demarcation line to the calcified cartilage. Using scanning electron microscopy, the tidemark was characterized as an electron-dense impression between hyaline and calcified cartilage. The presence of specific architecture and orientation of collagenous fibres could not be shown. Concentrations of calcium, phosphorus and sulphur could not be detected in the tidemark by means of an X-ray microanalyzer. A morphological model of the tidemark region was established, which represents the intercartilaginous junction as a double layer of substantially and functionally different surfaces.

Analyses of the tidemark on human femoral heads. II. Tidemark changes in osteoarthrosis--a histological and histomorphometric study in non-decalcified preparations.

Histological and histomorphometric examinations were carried out on 88 human femoral heads, 63 from patients with osteoarthrosis and 25 controls. The changes of the tidemark were found to be multiform in the osteoarthrotic process and could be classified into three degrees of severity. Low-grade tidemark changes were characterized by reduplications of the tidemark and discontinuities of the tidemark line, occurring also in about one third of the controls. Vascular invasion into the tidemark as well as incipient calcification of basal hyaline cartilage were observed in middle-grade tidemark alterations. High-grade changes were distinguished by the disappearance of the tide-mark, advanced mineralization and ossification of basal hyaline and calcified cartilage and finally by the "tidemark and bone bald". Measuring the thickness of intact and osteoarthrotic hyaline cartilage, calcified layer and subchondral bone plate, it was possible to determine some correlations between the tidemark state and the structures measured. Variations in subchondral bone volume could also influence the tidemark and cartilage changes. The important role of the intercartilaginous junction in the pathogenesis and progress of osteoarthrosis is stressed.

Osteoarthritis and bone: osteologic types of osteoarthritis of the hip.

To assess prognosis and indications for allografting articular surfaces, osteological examination is of increasing importance. In this study 93 femoral heads of patients with primary osteoarthritis could be differentiated into three osteologic types using histomorphometry: (1) the osteosclerotic type (77% of cases), (2) the hyperostotic type, with excessive neogenesis of bone all over the femoral head and increased formation of osteophytes (10% of cases), and (3) the osteopenic type, with decreased bone mass and features of bone remodelling, a greater occurrence of subchondral cysts, and small osteophytes (8% of cases). Radiological and clinical features to distinguish these groups are given. The consequences for pathogenesis and clinical practice are discussed.