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Sixty-eight primary total hip arthroplasty in sixty-two patients (average age: 56.2 years) were followed for a minimum of five years (mean: 7.3 years). In all patients a Harris-Galante prosthesis was used. The initial diagnosis was osteoarthritis in 65 hips and avascular necrosis in 3 hips. Forty hips (58.8%) had high degree acetabular dysplasia that necessitated performing autogenous femoral head bone grafting. Preoperatively, the mean Harris hip score was 53.1 points. At last follow-up the mean hip score was 91.2 points. Twelve patients (17.6%) complained of thigh pain, which disappeared within two years in ten hips. Two patients complained of mild thigh pain of more than two years duration. There were no limitations of the activities of daily living. Radiolucency at the component-bone interface were graded 30.9% on the acetabular side, and 64.7% on femoral side. In all cases the radiolucencies were less than 2 mm in width. Two femoral components were graded as loose, but no acetabular component was graded as loose. The extrusion of the acetabular liner was seen in one hip, which is considered to be a fatigue breakage due to its design. The authors conclude that cementless total hip arthroplasty in Japan has presented excellent results.
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PMID:Clinical results of Harris-Galante total hip arthroplasty without cement. Follow-up study of over five years. 943 77

A biomechanical failure of the collagen network is postulated in many hypotheses of the development of osteoarthritis with advancing age. Here we investigate the accumulation of non-enzymatic glycation (NEG) products in healthy human articular cartilage, its relation to tissue remodelling and its role in tissue stiffening. Pentosidine levels were low up to age 20 years, and increased linearly after this age. This indicates extensive tissue remodelling at young age, and slow turnover of collagen after maturity has been reached. The slow remodelling is supported by the finding that enzymatic modifications of collagen (hydroxylysine, hydroxylysylpyridinoline, and lysylpyridinoline) were not related to age. The high remodelling is supported by levels of the crosslink lysylpyridinoline (LP) as a function of distance from the articular surface. LP was highest at the surface in mature cartilage (>20 years), whereas in young cartilage (<10 years) the opposite was seen; highest levels were close to the bone. LP levels in cartilage sections at age 14 years are high at the surface and close to the bone, but they are low in the middle region. This indicates that maturation of cartilage in the second decade of life starts in the upper half of the tissue, and occurs last in the tissue close to the bone. The effect of NEG products on instantaneous deformation of cartilage was investigated as a functional of topographical variations in pentosidine levels in vivo and in relation to in vitro induced NEG. Consistently, higher pentosidine levels were associated with a stiffer collagen network. A stiffer and more crosslinked collagen network may become more brittle and more prone to fatigue.
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PMID:Ageing and zonal variation in post-translational modification of collagen in normal human articular cartilage. The age-related increase in non-enzymatic glycation affects biomechanical properties of cartilage. 946 29

A quantitative assessment of bone tissue stresses and strains is essential for the understanding of failure mechanisms associated with osteoporosis, osteoarthritis, loosening of implants and cell-mediated adaptive bone-remodeling processes. According to Wolff's trajectorial hypothesis, the trabecular architecture is such that minimal tissue stresses are paired with minimal weight. This paradigm at least suggests that, normally, stresses and strains should be distributed rather evenly over the trabecular architecture. Although bone stresses at the apparent level were determined with finite element analysis (FEA), by assuming it to be continuous, there is no data available on trabecular tissue stresses or strains of bones in situ under physiological loading conditions. The objectives of this project were to supply reasonable estimates of these quantities for the canine femur, to compare trabecular-tissue to apparent stresses, and to test Wolff's hypothesis in a quantitative sense. For that purpose, the newly developed method of large-scale micro-FEA was applied in conjunction with micro-CT structural measurements. A three-dimensional high-resolution computer reconstruction of a proximal canine femur was made using a micro-CT scanner. This was converted to a large-scale FE-model with 7.6 million elements, adequately refined to represent individual trabeculae. Using a special-purpose FE-solver, analyses were conducted for three different orthogonal hip-joint loading cases, one of which represented the stance-phase of walking. By superimposing the results, the tissue stress and strain distributions could also be calculated for other force directions. Further analyses of results were concentrated on a trabecular volume of interest (VOI) located in the center of the head. For the stance phase of walking an average tissue principal strain in the VOI of 279 strain was found, with a standard deviation of 212 microstrain. The standard deviation depended not only on the hip-force magnitude, but also on its direction. In more than 95% of the tissue volume the principal stresses and strains were in a range from zero to three times the averages, for all hip-force directions. This indicates that no single load creates even stress or strain distributions in the trabecular architecture. Nevertheless, excessive values occurred at few locations only, and the maximum tissue stress was approximately half the value reported for the tissue fatigue strength. These results thus indicate that trabecular bone tissue has a safety factor of approximately two for hip-joint loads that occur during normal activities.
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PMID:Tissue stresses and strain in trabeculae of a canine proximal femur can be quantified from computer reconstructions. 1021 36

A quantitative assessment of bone tissue stresses and strains is essential for the understanding of failure mechanisms associated with osteoporosis, osteoarthritis, loosening of implants and cell- mediated adaptive bone-remodeling processes. According to Wolff's trajectorial hypothesis, the trabecular architecture is such that minimal tissue stresses are paired with minimal weight. This paradigm at least suggests that, normally, stresses and strains should be distributed rather evenly over the trabecular architecture. Although bone stresses at the apparent level were determined with finite element analysis (FEA), by assuming it to be continuous, there is no data available on trabecular tissue stresses or strains of bones in situ under physiological loading conditions. The objectives of this project were to supply reasonable estimates of these quantities for the canine femur, to compare trabecular-tissue to apparent stresses, and to test Wolff's hypothesis in a quantitative sense. For that purpose, the newly developed method of large-scale micro-FEA was applied in conjunction with micro-CT structural measurements. A three-dimensional high-resolution computer reconstruction of a proximal canine femur was made using a micro-CT scanner. This was converted to a large-scale FE-model with 7.6 million elements, adequately refined to represent individual trabeculae. Using a special-purpose FE-solver, analyses were conducted for three different orthogonal hip-joint loading cases, one of which represented the stance-phase of walking. By superimposing the results, the tissue stress and strain distributions could also be calculated for other force directions. Further analyses of results were concentrated on a trabecular volume of interest (VOI) located in the center of the head. For the stance phase of walking an average tissue principal strain in the VOI of 279 strain was found, with a standard deviation of 212 microstrain. The standard deviation depended not only on the hip-force magnitude, but also on its direction. In more than 95% of the tissue volume the principal stresses and strains were in a range from zero to three times the averages, for all hip-force directions. This indicates that no single load creates even stress or strain distributions in the trabecular architecture. Nevertheless, excessive values occurred at few locations only, and the maximum tissue stress was approximately half the value reported for the tissue fatigue strength. These results thus indicate that trabecular bone tissue has a safety factor of approximately two for hip-joint loads that occur during normal activities.
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PMID:Tissue stresses and strain in trabeculae of a canine proximal femur can be quantified from computer reconstructions. 1005 22

The principal risk factors of osteoarthritis of the knee are: age, obesity and gender. It is hypothesized that long-duration walking (e. g. 20 min) in the elderly obese will lead to quadriceps fatigue. Changes in the gait pattern due to fatigue will lead to altered knee kinematics at heelstrike and consequently decreased shock absorption. This scenario will result in an increased rate of loading and possibly an increase in the overall magnitude of peak ground reaction forces, both of which could cause articular cartilage degeneration. Obese females are at an overall higher risk of developing osteoarthritis than males. This gender discrepancy may be explained by the fact that females have a higher percentage of body fat content (lower proportion of lean mass) that may increase the rate of quadriceps fatigue. These biomechanical hypotheses can be examined by studying continuous periods of walking in which ground reaction forces, knee kinematics and electromyography data are recorded.
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PMID:Obesity and osteoarthritis of the knee: hypotheses concerning the relationship between ground reaction forces and quadriceps fatigue in long-duration walking. 1079 Jul 48

This study examined the epidemiology and demographics of congenital hip disease in 468 (660 hips) patients who were examined between 1970 and 1996. In 356 (54%) hips, the diagnosis was secondary osteoarthritis due to congenital hip disease, and in 272 (41%) hips, the diagnosis was idiopathic osteoarthritis. In the remaining 32 (5%) hips, the diagnosis was uncertain. Of the hips with congenital hip disease, 170 (47.7%) hips were dysplastic, 85 (23.9%) had low dislocation, and 101 (28.4%) high dislocation. The majority of patients with congenital hip disease were women (338 [95%] hips). The natural history of the three types of congenital hip disease was studied in 157 patients (202 hips: 102 dysplastic, 42 low dislocation, and 58 high dislocation) who had received no treatment before the initial examination. Average length of follow-up was 17 years. In dysplastic hips, the disease remained undiagnosed until the onset of symptoms at an average age of 34.5 years. In patients with low dislocation, pain had started at an average of 32.5 years due to progressive degenerative arthritis within the false acetabulum. In patients with high dislocation, in the presence of a false acetabulum, pain started at an average age of 31.2 years, while in its absence, pain started at an average age of 46.4 years due to muscle fatigue. These findings suggest dysplasia, low dislocation, and high dislocation in adults are the results of untreated dysplasia, subluxation, and complete dislocation in infancy, respectively.
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PMID:Epidemiology, demographics, and natural history of congenital hip disease in adults. 1095 45

The objective of this study was to determine whether the Arthritis Self-Management Programme (ASMP) improves perceptions of control, health behaviours and health status, and changes use of health care resources. The design was a pragmatic randomized controlled study; participants were allocated to ASMP (Intervention Group) or a 4-month waiting-list Control Group. The Intervention Group completed a 12-month follow-up. In total, 544 people with arthritis were recruited from the community--311 in the Intervention Group and 233 in the Control Group. Main outcome measures included: arthritis self-efficacy, health behaviours (exercise, cognitive symptom management, diet and relaxation) and health status (pain, fatigue, anxiety, depression and positive affect). At 4 months follow-up, the ASMP had a significant effect on arthritis self-efficacy for other symptoms and pain subscales. Performance of a range of health behaviours (cognitive symptom management, communication with physicians, dietary habit, exercise and relaxation) was significantly greater among the Intervention Group. The Intervention Group were significantly less depressed and had greater positive mood. In addition, trends towards decreases on fatigue and anxiety were noted. Physical functioning, pain and GP visits remained stable at 4 months. A similar pattern of findings was found at 12 months follow-up for the Intervention Group. Furthermore, a significant improvement was found on pain and visits to GPs had decreased. Apart from a small improvement on physical functioning among the Intervention Group participants with osteoarthritis 12 months, all effects were independent of the type of arthritis. The findings suggest that the ASMP is effective in promoting improvements in perception of control, health behaviours and health status, when delivered in UK settings.
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PMID:A randomized controlled study of the Arthritis Self-Management Programme in the UK. 1114 74

Fibromyalgia (FM) is a syndrome of chronic widespread musculoskeletal pain that is accompanied by sleep disturbance and fatigue. Clinical treatment usually includes lifestyle modifications and pharmacologic interventions meant to relieve pain, improve sleep quality, and treat mood disorders. These therapies are often ineffective or have been shown in clinical studies to have only short-term effectiveness. Pharmacologic treatments have considerable side effects. Patients may have difficulty complying with exercise-based treatments. Thus, patients seek alternative therapeutic approaches and physicians are routinely asked for advice about these treatments. This article reviews nontraditional treatment alternatives, from use of nutritional and herbal supplements to acupuncture and mind-body therapy. Little is known about efficacy and tolerance of complementary and alternative therapies in FM and other chronic musculoskeletal pain syndromes. Most studies on these treatments have been performed for osteoarthritis, rheumatoid arthritis, or focal musculoskeletal conditions. Clinical trials are scarce; the quality of these trials is often criticized because of small study population size, lack of appropriate control interventions, poor compliance, or short duration of follow-up. However, because of widespread and growing use of alternative medicine, especially by persons with chronic illnesses, it is essential to review efficacy and adverse effects of complementary and alternative therapies.
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PMID:Complementary and alternative therapies for fibromyalgia. 1128 71

The basic morphology of the skeleton is determined genetically, but its final mass and architecture are modulated by adaptive mechanisms sensitive to mechanical factors. When subjected to loading, the ability of bones to resist fracture depends on their mass, material properties, geometry and tissue quality. The contribution of altered bone geometry to fracture risk is unappreciated by clinical assessment using absorptiometry because it fails to distinguish geometry and density. For example, for the same bone area and density, small increases in the diaphyseal radius effect a disproportionate influence on torsional strength of bone. Mechanical factors are clinically relevant because of their ability to influence growth, modeling and remodeling activities that can maximize, or maintain, the determinants of fracture resistance. Mechanical loads, greater than those habitually encountered by the skeleton, effect adaptations in cortical and cancellous bone, reduce the rate of bone turnover, and activate new bone formation on cortical and trabecular surfaces. In doing so, they increase bone strength by beneficial adaptations in the geometric dimensions and material properties of the tissue. There is no direct evidence to demonstrate anti-fracture efficacy for mechanical loading, but the geometric alterations engendered undoubtedly increase the structural properties of bone as an organ, increasing the resistance to fracture. Like all interventions, issues of safety also arise. Physical activities involving high strain rates, heavy lifting or impact loading may be detrimental to the joints, leading to osteoarthritis; may stimulate fatigue damage leading to stress fractures; or may interact with some pharmaceutical interventions to increase the rate of microdamage within cortical or trabecular bone.
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PMID:Mechanical effects on the skeleton: are there clinical implications? 1130 87

We have studied the incremental stress-strain behavior of human articular cartilage in tension in an attempt to understand the molecular basis for fibrillation and fissure formation in osteoarthritis. Our results indicate that the elastic spring constant for collagen in the direction per pendicular to the cleavage line pattern is about 1.6 GPa (2.3 GPa after correction for the collagen content) and the collagen fibril length is between 0.558 pm at low strains and 1.24 pm at high strains for normal cartilage. Values for the elastic spring constant and collagen fibril length were both found to decrease in OA. The value of the elastic spring constant for collagen perpendicular to the cleavage line pattern is similar to that calculated based on stress-strain curves reported by Kempson. Our results indicate that the elastic spring constant for collagen and the collagen fibril length decrease as the extent of fibrillation and fissure formation increase. Decreases in the elastic spring constant of collagen are consistent with loss of the superficial layer, degradation of proteoglycans and collagen, and subsequent mechanical fatigue. However, changes in the polymer volume fraction are consistent with enzymatic degradation preceding mechanical disruption. It is concluded that osteoarthritic changes to cartilage involve enzymatic degradation of matrix components and fibril fragmentation that is promoted by subsequent mechanical loading.
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PMID:Viscoelastic behavior of osteoarthritic cartilage. 1191 93


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