C-reactive protein of ≥ 20 mg/L and ultrasound finding of an effusion ≥ 7 mm has a high specificity and sensitivity in diagnosing paediatric hip septic arthritis

PURPOSE

Differentiating septic arthritis (SA) from transient synovitis (TS) in children remains a diagnostic challenge. Several algorithms have been developed to diagnose SA including Kocher's criteria and its subsequent modifications, but reports show variable efficacy. This study aims to examine the diagnostic utility of a novel method only using C-reactive protein (CRP) and ultrasound (US) findings of effusion in differentiating SA from TS, determine the optimal values for these predictors and validate this method against existing clinical predictors.

METHODS

A 5-year retrospective study was performed including all paediatric patients with acute, non-traumatic hip pain with a suspicion of SA. All patients were evaluated using Kocher's criteria, Caird's criteria, and the novel method. Multivariate logistic regression was performed to identify independent clinical predictors of SA. The degree of agreement between the various methods were assessed using Cohen's kappa (k). Receiver operating characteristics (ROC) curves were used to examine the diagnostic accuracy of this novel method as well as to determine optimal cut-offs for US effusion and CRP in diagnosing SA.

RESULTS

Hundred and one patients were recruited. CRP and effusion on US were found to be independent predictors of SA. Both Kocher's and Caird's method showed good specificity (98.9%) but extremely poor sensitivity for SA (0%). When Kocher's four clinical predictors were present, probability of SA was only 59.16%. The k for both Kocher's and Caird's methods, was -0.017 indicating poor agreement. However the k in the novel method was 0.641, indicating good agreement.

CONCLUSION

Our study showed that the novel method using CRP (≥ 20 mg/L) and US finding of effusion (≥ 7 mm) has a high specificity (97%) and sensitivity (71%) in diagnosing SA.

Laboratory-based versus qualitative assessment of α-defensin in periprosthetic hip and knee infections: a systematic review and meta-analysis

INTRODUCTION

Two methods are currently available for the assay of α-defensin: the enzyme-linked immunosorbent assay (ELISA) and the lateral flow test. We aimed to assess the diagnostic accuracy of synovial fluid α-defensin and to compare the accuracy of the laboratory-based test and the qualitative assessment for the diagnosis of hip and knee prosthetic infection.

MATERIALS AND METHODS

We searched (from inception to May 2018) MEDLINE, Scopus, EMBASE, Web of Science, and Cochrane for studies on α-defensin in the diagnosis of periprosthetic joint infection (PJI). Sensitivity, specificity, positive and negative likelihood ratio (LR), and diagnostic odds ratio were analyzed using the bivariate diagnostic random-effects model. The receiver-operating curve for each method was calculated.

RESULTS

We included 13 articles in our meta-analysis, including 1170 patients who underwent total hip and knee arthroplasties revision; 368 (31%) had a joint infection according to MSIS and MSIS-modified criteria. Considering the false-positive result rate of 8% and false-negative result rate of 3%, pooled sensitivity and specificity were 0.90 (95% CI 0.83-0.94) and 0.95 (0.92-0.96), respectively. The area under the curve (AUC) was 0.94 (0.92-0.94). No statistical differences in terms of sensitivity and specificity were found between the laboratory-based and qualitative test. The pooled sensitivity and specificity of the two alpha-defensin assessment methods were: laboratory-based test 0.97 (95% CI 0.93-0.99) and 0.96 (95% CI 0.94-0.98), respectively; qualitative test 0.83 (95% CI 0.73-0.91) and 0.94 (95% CI 0.89-0.97), respectively. The diagnostic odds ratio of the α-defensin laboratory based was superior to that of the qualitative test (1126.085, 95% CI 352.172-3600.702 versus 100.9, 95% CI 30.1-338.41; p < 0.001). The AUC for immunoassay and qualitative tests was 0.97 (0.95-0.99) and 0.91 (0.88-0.99), respectively.

CONCLUSION

Detection of α-defensin is an accurate test for diagnosis of hip and knee prosthetic infections. The diagnostic accuracy of the two alpha-defensin assessment methods is comparable. The lateral flow assay is a valid, rapid, and more available diagnostic tool, particularly to rule out PJI.

Solochrome cyanine: A histological stain for cobalt-chromium wear particles in metal-on-metal periprosthetic tissues

Metal-on-metal (MoM) hip arthroplasties produce abundant implant-derived wear debris composed mainly of cobalt (Co) and chromium (Cr). Cobalt-chromium (Co-Cr) wear particles are difficult to identify histologically and need to be distinguished from other wear particle types and endogenous components (e.g., haemosiderin, fibrin) which may be present in MoM periprosthetic tissues. In this study we sought to determine whether histological stains that have an affinity for metals are useful in identifying Co-Cr wear debris in MoM periprosthetic tissues. Histological sections of periprosthetic tissue from 30 failed MoM hip arthroplasties were stained with haematoxylin-eosin (HE), Solochrome Cyanine (SC), Solochrome Azurine (SA) and Perls' Prussian Blue (PB). Sections of periprosthetic tissue from 10 cases of non-MoM arthroplasties using other implant biomaterials, including titanium, ceramic, polymethylmethacrylate (PMMA) and ultra-high molecular weight polyethylene (UHMWP) were similarly analysed. Sections of 10 cases of haemosiderin-containing knee tenosynovial giant cell tumour (TSGCT) were also stained with HE, SC, SA and PB. In MoM periprosthetic tissues, SC stained metal debris in phagocytic macrophages and in the superficial necrotic zone which exhibited little or no trichrome staining for fibrin. In non-MoM periprosthetic tissues, UHMWP, PMMA, ceramic and titanium particles were not stained by SC. Prussian Blue, but not SC or SA, stained haemosiderin deposits in MoM periprosthetic tissues and TSGT. Our findings show that SC staining (most likely Cr-associated) is useful in distinguishing Co-Cr wear particles from other metal/non-metal wear particles types in histological preparations of periprosthetic tissue and that SC reliably distinguishes haemosiderin from Co-Cr wear debris.

Gout Presenting as Acute Hip Pain in a Young Woman: A Case Report

CASE

A 28-year-old previously healthy woman developed worsening right hip pain without any preceding trauma or injury. Because of concern for septic arthritis, she underwent arthroscopic irrigation and debridement. The culture specimens were negative; crystal analysis showed monosodium urate crystals, which are consistent with an acute gout flare. The patient was started on naproxen and prednisone therapy and had substantial improvement in hip pain.

CONCLUSION

Gout is a common cause of joint pain in older individuals. While rare in younger patients, our case report shows that gout should be included in the differential diagnosis when a patient presents with acute monoarthritis, regardless of age.

An analysis of factors affecting the mercury content in the human femoral bone

The study was carried out to determine the content of mercury in bone tissue of the proximal femur (head and neck bone) of 95 patients undergoing total hip replacement due to osteoarthritis, using CF-AFS analytical technique. Furthermore, the investigations were aimed at assessing the impact of selected factors, such as age, gender, tobacco smoking, alcohol consumption, exposure to chemical substance at work, type of degenerative changes, clinical evaluation and radiological parameters, type of medications, on the concentration of mercury in the head and neck of the femur, resected in situ. Mercury was obtained in all samples of the head and neck of the femur (n = 190) in patients aged 25-91 years. The mean content of mercury for the whole group of patients was as follows: 37.1 ± 35.0 ng/g for the femoral neck and 24.2 ± 19.5 ng/g for the femoral head. The highest Hg contents were found in femoral neck samples, both in women and men, and they amounted to 169.6 and 176.5 ng/g, respectively. The research showed that the mercury content of bones can be associated with body mass index, differences in body anatomy, and gender. The uses of statistical analysis gave the possibility to define the influence of factors on mercury content in human femoral bones.

Involvement of Notch1/Hes signaling pathway in ankylosing spondylitis

We aimed to investigate the role of Notch1/Hes signaling pathway in the pathogenesis of abnormal ossification of hip ligament in patients with ankylosing spondylitis (AS). 22 AS patients scheduled for artificial hip arthroplasty were randomly chosen as AS group. As controls, we used 4 patients diagnosed with transcervical fracture who underwent hip replacement surgery. Notch1 and Hes mRNA expressions were detected by real-time fluorescent quantitative polymerase chain reaction (RFQ-PCR). Immunohistochemistry (IHC) was used to detect Notch1 and Hes protein expression. Correlation analyses of Notch-l and Hes with AS-related clinical factors were conducted with spearman's correlation analysis and partial correlation analysis. RFQ-PCR results showed significant differences in Notch1 and Hes mRNA expressions between AS group and the control group (all P<0.05). IHC analysis further indicated positive nuclear signals of Notch1 and Hes protein, indicating functional activation of the Notch1 and Hes pathways. Semi-quantitative IHC showed a higher Notch1 and Hes expression levels in AS group compared to the control group (all P<0.05). Correlation analysis suggested that Hes protein expression was positively associated with the clinical course of the disease in AS patients. In conclusion, Notch1 and Hes overexpression was clearly detected in hip joint ligaments of AS patients, Hes protein expression was associated with the clinical course of AS. Taken together, we suggest that signaling pathways mediated by Notch1-Hes may contribute to ligament ossification of hip joints in AS patients.

Chromium content in the human hip joint tissues

OBJECTIVE

Chromium has many important functions in the human body. For the osseous tissue, its role has not been clearly defined. This study was aimed at determining chromium content in hip joint tissues.

METHODS

A total of 91 hip joint samples were taken in this study, including 66 from females and 25 from males. The sample tissues were separated according to their anatomical parts. The chromium content was determined by the AAS method. The statistical analysis was performed with U Mann-Whitney's non-parametric test, P≤0.05.

RESULTS

The overall chromium content in tissues of the hip joint in the study subjects was as follows: 5.73 µg/g in the articular cartilage, 5.33 µg/g in the cortical bone, 17.86 µg/g in the cancellous bone, 5.95 µg/g in the fragment of the cancellous bone from the intertrochanteric region, and 1.28 µg/g in the joint capsule. The chromium contents were observed in 2 group patients, it was 7.04 µg/g in people with osteoarthritis and 12.59 µg/g in people with fractures.

CONCLUSION

The observed chromium content was highest in the cancellous bone and the lowest in the joint capsule. Chromium content was significantly different between the people with hip joint osteoarthritis and the people with femoral neck fractures.

Mild degenerative changes of hip cartilage in elderly patients: an available sample representative of early osteoarthritis

This study investigated the cellular and molecular changes which occur in cartilage from adults with femoral neck fracture (FNF) and osteoarthritis (OA), and explored the similarities in hip cartilage obtained from elderly patients and patients with early OA. Femoral heads were retrieved from 23 female patients undergoing total hip arthroplasty (THA). This group included 7 healthy patients with FNF (hFNF), 8 elderly adults with FNF (eFNF), and 8 elderly patients with hip OA (OA). After high-field MRI T2 mapping, osteochondral plugs were harvested from the weight-bearing area of femoral heads for subsequent macroscopic, histologic, and immunochemical evaluation. Additionally, the contents of cartilage matrix were analyzed, and gene expression was detected. The surface of cartilage from hFNF and eFNF patients appeared smooth, regular, and elastic, whereas it showed irregularities, thinning, and defects in OA patients. Elevated T2 values and decreased accumulation of glycosaminoglycans (GAGs) were detected in cartilage from eFNF patients. Furthermore, type I collagen accumulation was slightly increased and type X collagen concentration was obviously elevated in eFNF patients; however, type II collagen distribution and the contents and anisotropy of collagen fibrils in eFNF patients showed no significant changes. Consistent with histology and immunohistochemical results, aggrecan was downregulated and type X collagen was upregulated, while collagens types I and II showed no significant changes in eFNF patients. The cellular and molecular characteristics of hip cartilage in eFNF patients who showed no symptoms of OA were similar to those in patients with mild OA. Thus, eFNF cartilage can serve as a comparative specimen for use in studies investigating early OA.

The content of manganese and iron in hip joint tissue

Manganese and iron are elements that constitute components of bone tissue. The aim of this study was to determine presence of manganese and iron in hip joint tissue and interdependencies between these elements. The objects of the research were hip joint elements from people residing in cities on the territory of the Upper Silesian Industrial District. The number of people in the study group was 91 samples, including 66 samples from women and 25 from a man. The examined tissues were obtained intraoperatively during hip replacement procedures. The content of manganese and iron was determined using the atomic absorption spectrophotometry (AAS) method. The lowest content of manganese and iron was found in the cortical bone, and the largest, in the case of manganese, in the articular cartilage, whereas in the case of iron in a fragment of the cancellous bone from the intertrochanteric area. The content of iron in selected elements of the hip joint decreased with age. Higher content of manganese in hip joint tissue of women compared to men was confirmed. What is more, higher content of iron in hip joint tissue of men was confirmed as well.

Thyroid dysfunction in an adult female population: A population-based study of Latin American Vertebral Osteoporosis Study (LAVOS) - Puerto Rico site

OBJECTIVE

To determine the prevalence of hypothyroidism in an adult female population in Puerto Rico and to determine the relationship between hypothyroidism, bone mineral density and vertebral and non-vertebral fractures in this population.

METHODS

Data from the 400 subjects' database of the Latin American Vertebral Osteoporosis Study (LAVOS), Puerto Rico site was reviewed. Patient's medical history, anthropometric data, current medications, laboratories, and DXA results was extracted. Subjects with thyroid dysfunction were identified based on their previous medical history and levels of TSH. Bone Mineral Density was classified using the World Health Organization criteria. Crude prevalence of thyroid dysfunction were estimated with a confidence of 95% and weighted by the population distribution by age, according to the distribution by age group in the 2000 census. Bone mineral densities and prevalence of vertebral and non-vertebral fractures were compared among the groups.

RESULTS

The weighted prevalence of hyperthyroidism in this population was 0.0043% (95% CI: -0.0021%, 0.0107%). The weighted prevalence of hypothyroidism was 24.2% (95% CI: 19.9%, 28.4%). Increased prevalence of hypothyroidism was found in participants 70 years or older. The mean BMD at spine, hip and femoral neck was similar among the groups. No difference in the proportion of participants with vertebral and non-vertebral fractures was found among the groups.

CONCLUSION

Our study found a high prevalence of hypothyroidism among adult postmenopausal females in Puerto Rico. No association between hypothyroidism and decreased bone mineral densities, vertebral or non-vertebral fractures was found in this population.

The effect of environmental factors on concentration of trace elements in hip joint bones of patients after hip replacement surgery

The aim of this study was to assess the impact of environmental factors: cigarette smoking, dental amalgam fillings, eating habits and osteoporosis, on the concentrations of copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd) and mercury (Hg) in the bone of hip joint in patients in the Orthopedics Clinic in Szczecin, Poland. Amalgam dental fillings had an effect on the Cu concentration in the cartilage with the adjacent compact bone, and on Hg concentration in the spongy bone. The highest concentrations of Cu and Hg were found in people with multiple amalgam fillings. Smoking appeared to influence Pb concentration in the cartilage with the adjacent compact bone, and Cd concentration in the spongy bone. Increased Pb was detected in smokers, and increased Cd in non-smokers. Diets rich in fish and seafood correlated with Cd concentration in the cartilage with adjacent compact bone. The greatest concentration was in people who ate fish or seafood at least once a month.

Association between ghrelin levels and BMD: a cross sectional trial

OBJECTIVE

Our aim was to determine whether the level of plasma total ghrelin varies with the menopause stage (pre-, peri-, and postmenopause).

PARTICIPANTS AND INTERVENTIONS

Women were divided in three groups: premenopausal, perimenopausal and postmenopausal. All participants had bone mineral densitometry and blood assay of plasma ghrelin, estradiol E2. Correlation between plasma ghrelin levels, their reproductive status and BMD was done.

RESULTS

The mean plasma level of ghrelin was significantly decreased in the perimenopausal and postmenopausal groups in comparison to the premenopausal group. A significant positive correlation was found between ghrelin and each of E₂ and BMD (at one or more of the three sites assessed) in all subjects, as well as, in peri- and postmenopausal women, whereas a significant negative correlation was found between ghrelin and FSH.

CONCLUSION

It may be assumed that ghrelin can affect BMD. Whether ghrelin and estrogen work independent or through convergent mechanisms needs further studies.

Identifying compositional and structural changes in spongy and subchondral bone from the hip joints of patients with osteoarthritis using Raman spectroscopy

Raman microspectroscopy was used to examine the biochemical composition and molecular structure of extracellular matrix in spongy and subchondral bone collected from patients with clinical and radiological evidence of idiopathic osteoarthritis of the hip and from patients who underwent a femoral neck fracture, as a result of trauma, without previous clinical and radiological evidence of osteoarthritis. The objectives of the study were to determine the levels of mineralization, carbonate accumulation and collagen quality in bone tissue. The subchondral bone from osteoarthritis patients in comparison with control subject is less mineralized due to a decrease in the hydroxyapatite concentration. However, the extent of carbonate accumulation in the apatite crystal lattice increases, most likely due to deficient mineralization. The alpha helix to random coil band area ratio reveals that collagen matrix in subchondral bone is more ordered in osteoarthritis disease. The hydroxyapatite to collagen, carbonate apatite to hydroxyapatite and alpha helix to random coil band area ratios are not significantly changed in the differently loaded sites of femoral head. The significant differences also are not visible in mineral and organic constituents' content in spongy bone beneath the subchondral bone in osteoarthritis disease.

Concentrations of trace elements in bones of the hip joint from patients after hip replacement surgery

The aim of this research was to determine the concentrations of two essential elements (copper (Cu) and zinc (Zn)) and three toxic elements (lead (Pb), cadmium (Cd) and mercury (Hg)) in the hip joint bones of patients from the Chair and Clinic of Orthopaedics and Traumatology at the Pomeranian Medical University in Szczecin. We examined 111 samples of hip joint bones obtained from patients from north-western Poland who had undergone arthroplasty of the femoral head. In cartilage with the adjacent compact bone, and in spongy bone from the examined patients, the concentrations (medians) determined were placed in the following descending sequence Zn>Pb>Cu>Cd>Hg. The concentrations ranged from 86 mg Zn/kg to 0.0020 mg Hg/kg dw. It was found that the concentration of lead in the cartilage with adjacent compact bone was higher in men than in women. In conclusion, it seems that in addition to routine monitoring of the abiotic environment, it is essential to monitor concentrations of heavy metals having a long-term impact in humans.

Lead and calcium content in the human hip joint

Concentration of lead in bone, unlike in soft tissues, increases during the lifetime and reflects severity of exposure to this element. The main aim of the study was to determine concentrations of lead and calcium and to find possible relationship between calcium and lead in the tissues of the hip joints obtained from inhabitants of the Upper Silesian Industrial Area. We also attempted to identify factors that might affect this relationship. The samples were harvested intraoperatively during total hip replacement procedures; in most cases, the indication for the surgery was hip osteoarthritis. Concentrations of lead and calcium were measured with a Pye Unicam SP-9 acetylene-oxygen flame atomic absorption spectrometer. The highest mean concentration of lead was found in the cancellous bone from the femoral head, followed by articular cartilage, cortical bone and the intertrochanteric cancellous bone (0.75 μg/g). The smallest concentration was found in the joint capsule (0.19 μg/g). The highest mean concentration of calcium was found in cancellous bone from the femoral head, followed by cancellous bone from the intertrochanteric area, cortical bone, articular cartilage and joint capsule. The concentration of lead showed no correlation with sex. The bone concentration of calcium decreased with age. In the analysed hips, this finding was true in the cortical bone, as well as in the cancellous bone of the intertrochanteric area. Statistically significant correlation between calcium and lead was found only in the hip articular cartilage.

Human bones obtained from routine joint replacement surgery as a tool for studies of plutonium, americium and ⁹⁰Sr body-burden in general public

The paper presents a new sampling method for studying in-body radioactive contamination by bone-seeking radionuclides such as (90)Sr, (239+240)Pu, (238)Pu, (241)Am and selected gamma-emitters, in human bones. The presented results were obtained for samples retrieved from routine surgeries, namely knee or hip joints replacements with implants, performed on individuals from Southern Poland. This allowed to collect representative sets of general public samples. The applied analytical radiochemical procedure for bone matrix is described in details. Due to low concentrations of (238)Pu the ratio of Pu isotopes which might be used for Pu source identification is obtained only as upper limits other then global fallout (for example Chernobyl) origin of Pu. Calculated concentrations of radioisotopes are comparable to the existing data from post-mortem studies on human bones retrieved from autopsy or exhumations. Human bones removed during knee or hip joint surgery provide a simple and ethical way for obtaining samples for plutonium, americium and (90)Sr in-body contamination studies in general public.

[Bone mineral density in patients with type 2 diabetes]

OBJECTIVE

To establish whether type 2 diabetes (T2D) is associated with changes in the bone mineral density (BMD) of femoral neck, total hip and lumbar spine.

MATERIAL AND METHODS

Comparative cross-sectional study that included 450 patients aged 30 years or more; 245 with, and 205 without T2D. Groups were matched by age. Degenerative joint disease, rheumatoid arthritis, neoplasia, renal failure, chronic liver disease, alcohol intake, prior treatment with drugs that modulate the BMD, Diabetes Mellitus Type 1 and other endocrinopathies were exclusion criteria.

RESULTS

In the overall group, the presence of menopause was associated with osteoporosis in the hip (odds ratio -OR-4.2; CI95% 1.4-6.1), whereas T2D was a protective factor (OR 0.8; CI95% 0.4-0.9). Among premenopausal women, central obesity and total adiposity were associated with osteoporosis in the hip (OR 1.9; CI95% 1.1-3.9 and OR 2.1; CI95% 1.2-8.7) and femoral areas (OR 2.1; CI95% 1.2-4.1 and OR 2.3; CI95% 1.3-7.1); T2D remained as protective factor (OR 0.7; CI95% 0.5-0.9 and OR 0.6; CI95% 0.4-0.9). The adjusted analysis by BMI, waist circumference, and total adiposity showed that T2D remained as a protective factor for osteoporosis in the hip (OR 0.8; CI95% 0.6-0.9) and femoral areas (OR 0.7; CI95% 0.5-0.9).

CONCLUSIONS

Our results suggest that T2D is an independent protective factor for osteoporosis.

[Distribution and expression of TGF-ß2 in the capsule of children with developmental dysplasia of the hip]

OBJECTIVE

This study examined the distribution and expression of transforming growth factor-ß₂ (TGF-ß₂) in the hip capsule of children with developmental dysplasia (dislocation) of the hip (DDH) and non-DDH children in order to investigate the roles of TGF-ß₂ in hip joint laxity.

METHODS

Eight children with DDH and eight age- and gender-matched non-DDH children (control group) were enrolled. The immunohistochemical technique (S-P method) was used to examine the distribution and content of TGF-ß₂ in the hip capsule. Semiquantitative RT-PCR method was used to detect mRNA expression of TGF-ß₂ in the hip capsule. The quantitative analysis of TGF-ß₂ was performed by professional image software.

RESULTS

A high expression of TGF-ß₂ was observed in the synovial layer with fibroblast regularly arranged parallel to the joint surface. There was decreased expression of TGF-ß₂ in the fibrous layer of the capsule. The percentage of positive fibroblasts and the gray-scale density in the fibrous layer in the DDH group were significantly lower than those in the control group (P < 0.01). TGF-ß₂ mRNA expression in the DDH group decreased compared with that in the control group (P < 0.05).

CONCLUSIONS

The decreased TGF-ß₂ in distribution, content and mRNA expression in the hip capsule might contribute to hip joint laxity in children with DDH.

Ultrastructural Cytochemical and Ultrastructural Morphological Differences Between Human Multinucleated Giant Cells Elicited by Wear Particles from Hip Prostheses and Artificial Ligaments at the Knee

The authors investigated the ultrastructural cytochemical features of multinucleated and mononuclear cells in periprosthetic tissues associated with bone resorption (osteolysis) and those in tissues adjoining failed artificial ligaments having no relation to bone resorption. Clinical specimens of granulation tissue of each type, respectively numbering 4 and 3, were stained for tartrate-resistant acid phosphatase (TRAP) reactions and examined by light and electron microscopy. Both periprosthetic granulation tissues and those adjoining artificial ligaments contained TRAP-positive multinucleated and mononuclear cells. Near joint prostheses, multinucleated cells, including some giant cells, showed TRAP activity and cytoplasmic features resembling osteoclasts, while others had features consistent with foreign-body giant cells, and still others showed degenerative changes. Near artificial ligaments, TRAP-positive multinucleated cells lacked osteoclastic features. At both sites, TRAP-positive multinucleated cells had phagocytised wear particles. TRAP-positive mononuclear cells at both sites also showed phagocytic cytoplasmic features, but not osteoclastic cytoplasmic features. Human mononuclear phagocytes and multinucleated giant cells induced by wear particles possess TRAP activity. Those multinucleated giant cells at sites of osteolysis developed osteoclastic cytoplasmic features and have a phagocytic function.

[The occurance lead and cadmium in hip joint in aspect of exposure on tobacco smoke]

The objective of this study was qualification of content cadmium and lead in selected elements of the hip joint in aspect of tobacco smoking. The material for the research were 5 elements of hip joint (articular cartilage, trabecular bone and cortical bone femur head, fragment articular capsule and fragment trabecular bone from region intertrochanteric femoral bone), obtained intraoperatively during endoprothesoplastic surgeries. The samples come from habitants of Upper Silesian Region. Determination of trace elements contents were performed by ASA method (Pye Unicam SP-9) in acetylene-oxygen flame. Higher contents of lead were observed for smoking people, however in case of cadmium the differences of this element were not statistical essential between smokers and non-smokers.

Wear and biological activity of highly crosslinked polyethylene in the hip under low serum protein concentrations

Crosslinked ultra-high molecular weight polyethylene (UHMWPE) has been developed and introduced into clinical practice in order to reduce wear in the hip. Zero wear of highly crosslinked UHMWPE in vitro has been reported by some groups using lubricants with high concentrations of serum proteins in hip simulators. In contrast, some clinical studies have reported finite wear rates. The aim of this study was to compare the wear rates, wear surfaces, and wear debris produced by UHMWPE with different levels of crosslinking in a hip joint simulator, with lower, more physiologically relevant concentrations of protein in the lubricant.

The UHMWPEs were tested in the Leeds ProSim hip joint simulator against cobalt-chromium (CoCr) femoral heads. The wear particles were isolated and imaged using a field emission gun scanning electron microscope (FEGSEM) at high resolution. The highly crosslinked UHMWPEs had significantly lower wear volumes than the non-crosslinked UHMWPEs. No significant difference was found in the percentage number and percentage volume of the particles in different size ranges from any of the materials. They had similar values of specific biological activity. The functional biological activity (FBA), which takes into account the wear volume and specific biological activity, showed that the highly crosslinked UHMWPEs had lower FBAs due to their lower wear volume.

[Examination of granuloma of revised cemented or cementless total hip arthroplasties using inductively coupled plasma atomic emission spectrometry (ICP-OES)]

INTRODUCTION

Aseptic loosening is the most common problem in total hip arthroplasty (THA). One main aspect is inflammatory reaction against wear particles of the prosthesis materials. Analysing failure mechanisms in THA analysis of the particles and their element distribution of revised granulomatous tissue is essential to improve materials used in THA.

MATERIALS AND METHODS

23 granulomas of revised THA due to aseptic loosening, 13 of which with metal on metal bearing (M/M), were analysed using inductively coupled plasma atomic emission spectrometry (ICP-OES).

RESULTS

Elements Cr, Mn, Ni, Al, Cu, Zn, Cd, Ti, V, Zr, Nb and Fe could be detected. The maximum value of Cr was 23.88 ppb (parts per billion), Al 191.02 ppb, Ni 64.95 ppb and Zr 9.96 ppb. The highest value of Al could be found in cementless implants. The maximum value of the elements Cr and Ni could be detected in M/M. In cemented implants the highest value of Zr was found.

DISCUSSION

The origin of Zr was the used bone cement in cemented THA. The elements Cr and Ni were significantly higher in M/M bearings. The highest value of Al was detected in granulomas of revised corund rough blasted cementless implants. The histopathologic findings of the revised M/M bearings have been published recently. Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-OES) could not show any differences of the alloying constituents in cases with or without allergic reactions. ICP-OES analysis seems to be not useful examination of histologic sections using SEM with cryotransfer unit.

[Cytokines and bone turnover markers]

OBJECTIVE

Bone turnover markers (osteocalcin, bone-ALP, beta-crosslaps--CTX) and cytokines (IL-1 alpha, IL-8 and IL-10) in hip joint fluid were analyzed in patients with aseptic loosening of prosthesis before revision surgery, in patients with rheumatoid arthritis and with idiopathic coxarthrosis for comparison.

METHODS

Bone turnover markers were determined by electrochemiluminescence, colorimetric or ELISA method and cytokines by ELISA in joint fluid collected at the beginning of the surgery.

RESULTS

Patients with loose implants had lower concentration of the resorption marker than cases with rheumatoid arthritis and coxarthrosis (7771 +/- 3322 vs 25986 +/- 16059 p < 0.01 and 23047 +/- 32556 pmol/L, p < 0.003) and over tenfold lower concentration of osteocalcin, the bone formation marker (p < 0.04 i p < 0.01). Concentration of IL-8 was elevated and similar in patients with loosening and rheumatoid arthritis while in cases with osteoarthrosis the mean value was twice lower. The anti-inflammatory IL-10 was highly elevated only in cases with prosthesis loosening. Additionally, a negative correlation was observed between CTX and IL-10 was and positive between IL-10 and time to revision surgery.

CONCLUSIONS

We conclude that increased local production of inflammatory cytokines leading to uncoupling of bone turnover is a part of the loosening process.

Differences in bone mineral density, bone mineral content, and bone areal size in fracturing and non-fracturing women, and their interrelationships at the spine and hip

Osteoporotic fractures are a major public health problem, particularly in women. Bone mineral density (BMD), bone mineral content (BMC), and bone size have been regarded as important determinants of osteoporotic fractures. In 1449 women over age 30 years, we studied the detailed relationship, at the spine and hip, between BMD, BMC, and bone areal size (all measured by dual-energy X-ray absorptiometry) and compared their relative magnitudes in fracturing and non-fracturing individuals. We find that, (1) BMD and BMC are significantly higher at the spine and hip in non-fracturing women. Bone areal size is significantly larger at the spine in non-fracturing women; however, the significance disappears when adjustment is made for the significant difference of height (stature) between fracturing and non-fracturing women. In contrast to the spine, bone areal size is always significantly largerin fracturing women at the hip. (2) The relationship among BMD, BMC, and bone areal size is different at the spine and hip. Specifically, at the spine, BMD increases with bone areal size linearly. At the hip, BMD has a quadratic relationship with bone areal size, so that BMD increases at lower bone areal sizes, then (after an intermediate zone of values) decreases with increasing bone areal size. However, BMD adjusted for BMC always decreases with increasing bone areal size, as expected by the definition of BMD. With no adjustment for BMC, the increase in BMD with bone areal size is due to a more rapid increase of BMC than increasing bone areal size, thus explaining the observations of association of both larger BMD and larger bone areal size with stronger bone. (3) At the spine, 86.2% of BMD variation is attributable to BMC and 12.6% to bone areal size. At the hip, 98.0% of BMD variation is due to BMC and 1.1% due to bone areal size. The current study may be important in understanding the relationship among BMD, BMC, and bone size as risk determinants of osteoporotic fractures.

Southern analysis of mitochondrial DNA in cortical bone of elderly patients undergoing knee and hip arthroplasty

The role of mitochondrial DNA deletions (dmtDNA) in involutional bone loss seen in elderly men and women has never been examined. The present investigation was carried out to determine the extent of dmtDNA in cortical bone of elderly patients undergoing knee and hip arthroplasties. The majority of earlier studies have employed the polymerase chain reaction (PCR) to detect and quantify dmtDNA in different body tissues. In the present study, Southern blotting was used to screen bone biopsies from 30 patients undergoing orthopaedic surgery (mean age+/-SD 67.5+/-9.6 years; range 49-87 years). The blotting of PvuII-digested genomic DNA, carried out using mtDNA probes covering the entire span of mtDNA, revealed high levels of deletions in six subjects (mean age+/-SD 63.0+/-10.1 years; range 49-78 years) and moderate to low levels of mutations in another 14 subjects (mean age+/-SD 64.9+/-8.9 years; range 53-87 years). The importance of this rather high prevalence of dmtDNA in the bone of the elderly is discussed in terms of possible involvement of increased production of oxygen-derived free radicals and oxidative stress, and its possible role in the accelerated bone loss leading to osteoporosis.

The hip joint: the fibrillar collagens associated with development and ageing in the rabbit

The fibrillar collagens associated with the articular cartilages, joint capsule and ligamentum teres of the rabbit hip joint were characterised from the 17 d fetus to the 2-y-old adult by immunohistochemical methods. Initially the putative articular cartilage contains types I, III and V collagens, but when cavitation is complete in the 25 d fetus, type II collagen appears. In the 17 d fetus, the cells of the chondrogenous layers express type I collagen mRNA, but not that of type II collagen. Types III and V collagens are present throughout life, particularly pericellularly. Type I collagen is lost. In all respects, the articular cartilage of the hip joint is similar to that of the knee. The joint capsule contains types I, III and V collagens. In the fetus the ligamentum teres contains types I and V collagens and the cells express type I collagen mRNA; type III collagen is confined mainly to its surface and insertions. After birth, the same distribution remains, but there is more type III collagen in the ligament, proper. The attachment to the cartilage of the head of the femur is marked only by fibres of type I collagen traversing the cartilage; the attachment cannot be distinguished in preparations localising types III and V collagens. The attachment to the bone at the lip of the acetabulum is via fibres of types I and V collagens and little type III is present. The ligament is covered by a sheath of types III and V collagens. Type II collagen was not located in any part of the ligamentum teres. The distribution of collagens in the ligamentum teres is similar to that in the collateral ligaments of the knee. Its insertions are unusual because no fibrocartilage was detected.

Immunohistochemical analysis of type-X-collagen expression in osteoarthritis of the hip joint

Conflicting data have been reported on the spatial distribution of type X-collagen expression in osteoarthritis, and no concise data exist on a possible correlation between type X-collagen expression and clinical and radiological alterations. Well defined clinical and radiological data were compared with histopathological and immunohistochemical findings to investigate the expression of type-X collagen in osteoarthritis of the hip joint. Femoral heads were obtained in toto from 11 patients undergoing routine hip arthroplasty for femoral neck fractures (n = 3) or osteoarthritis (n = 8) and from 13 patients (age: 12 days to 69 years) without any evidence of hip-joint pathology. Whole coronal sections from the femoral head were decalcified for routine histology and immunohistochemical analysis with use of type-specific monoclonal antibodies to type-X collagen. Our results demonstrate that type-X collagen is consistently found in osteoarthritic cartilage and is absent from normal adult cartilage (including the region of calcified cartilage). Except for the occurrence of type-X collagen in the middle zone of articular cartilage in advanced stages of osteoarthritis, there is no specific change in the staining pattern or intensity for the collagen during osteoarthritis, particularly when the staining is related to clinical and radiological parameters. Hardly more than 20% of the extracellular matrix stained for type-X collagen; therefore, we suggest that, in most cases, this type of collagen may not play a direct biomechanical role in the weakening of osteoarthritic cartilage but rather may contribute indirectly to a disturbance of the disc biomechanics by altering matrix-molecule interaction. However, expression of type-X collagen may indicate a change in chondrocyte phenotype that consistently coincides with the formation of chondrocyte clusters, one of the first alterations in osteoarthritis visible on histologic examination.

Non-invasive assessment of bone density in primary biliary cirrhosis

BACKGROUND/AIMS

Low bone mass is an important complication of primary biliary cirrhosis (PBC), resulting in an increased risk of fractures and reduced mobility. In the present study, we sought to determine the frequency of low bone mass in PBC, and its relationship to disease severity and non-invasive markers of bone turnover.

METHODS

In 36 women with PBC, bone mineral density of the lumbar spine and hip was assessed by dual emission X-ray absorptiometry. Serum and urinary markers of bone turnover were compared with those from age- and sex-matched controls.

RESULTS

Spinal osteopenia (T score, -1.5 to -2.5) was present in 15 of the 36 patients (42%), while six others (16%) had established osteoporosis (T < -2.5). Osteopenia of the femoral neck was found in 17 patients (47%), and osteoporosis in five (14%). The severity of liver disease, as determined by Mayo Clinic R score and histological stage, correlated negatively with both regional bone mineral density and total bone mineral content expressed as a ratio to lean body mass. There was a strong positive correlation between serum levels of the procollagen degradation peptides, PICP and PIIINP (r = 0.65, P < 0.001), and both peptides correlated significantly (P < 0.001) with histological stage and Mayo Clinic R score. Fasting urinary pyridinoline and deoxypyridinoline to creatinine ratios were also significantly raised.

CONCLUSIONS

Low bone mass in PBC correlates positively with disease severity, and is associated with a net increase in bone resorption, as assessed by urinary collagen cross-link excretion. These markers of bone turnover may be of value in controlled clinical trials aimed at improving bone mass in PBC.

[Relation between body mass index and bone mineral density in a sample population of Mexican women]

The purpose of this trial is to demonstrate that a women with high body mass index (BMI > or = 28) has greater bone mineral density (BMD) from that with lower BMI. We studied 922 healthy women who met the inclusion criteria. They were classified into four groups according to their BMI (> or = 28 and < 28) and age (> or = 35 and < 35 years). Bone mineral measurement was performed by dual-energy X-ray absorptiometry (DEXA) in the hip and at the lumbar region. BMD in overweight women older than 35 years was significantly higher in comparison with that of women with lower BMI, both in the hip and the lumbar spine. In overweight women younger than 35 years, we found greater BMD in the hip reaching statistical significance, but not at the lumbar spine. We conclude that obesity is associated with greater BMD (4% at the lumbar spine; 11% at the hip) probably due to both greater physical stress and higher estrogen levels.

Immunolocalization of inducible nitric oxide synthase in synovium and cartilage in rheumatoid arthritis and osteoarthritis

Nitric oxide has been implicated as a mediator of inflammatory arthritis, and recent work has shown that pro-inflammatory cytokines stimulate NO production in vitro by activation of the inducible nitric oxide synthase (iNOS) pathway. In order to identify the cellular sources of NO production within the joint, we have used immunohistochemical techniques to study the distribution of iNOS in synovium and cartilage from normal and diseased joints. iNOS was most strongly expressed in the synovial lining layer, subsynovium, vascular smooth muscle and chondrocytes from patients with rheumatoid arthritis (RA). Analysis of serial sections, coupled with double immunofluorescent staining, showed that the CD68+ macrophages in the synovial lining layer and, to a lesser extent, fibroblasts were the predominant source of iNOS within synovium, whereas T cells, B cells and neutrophils were negative. A similar pattern of iNOS staining was seen in osteoarthritis, but fewer cells were iNOS positive and the intensity of staining, particularly in cartilage, was much weaker than in RA. In contrast, no evidence of iNOS was detected in non-inflammatory synovium or in cartilage derived from normal joints (fractured neck of femur). In conclusion, these data support the hypothesis that synovium and cartilage are important sources of increased NO production in patients with inflammatory arthritis. Localization of iNOS at these sites within the inflamed joint raises the possibility that increased local production of NO may contribute to the pathogenesis of inflammatory arthritis by increasing synovial blood flow and by modulating cellular function within synovium and articular cartilage.

The plasminogen activation system is upregulated in loosening of total hip prostheses

Interface tissues and pseudocapsules from loose total hip replacements were removed during revision of 11 cases and were investigated for the plasminogen activation system and IL-1beta. Control samples of synovium were taken during knee arthroscopy (n 8), and from the hip joint during primary total hip replacement (n 5). The concentrations of urokinase plasminogen activator (uPA), tissue type plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1) and interleukin 1beta were all found to be significantly different in interfaces and in pseudocapsules, compared to controls. Immunohistochemistry disclosed localization in periprosthetic tissues of uPA, uPA-receptor and tPA in macrophages with phagocytosed metal, polyethylene, cement particles or accompanying pieces of necrotic bone. PAI-1 staining was present in the neighboring areas that stained for uPA or tPA, but PAI-1 staining was also found overlapping and outside these areas. These findings suggest a role for the uPA/uPA- receptor and PAI-1 in activation and focalization of extracellular matrix degradation in periprosthetic tissues. The expression of the plasminogen activation system by macrophages containing phagocytosed material suggests undegradable microdebris as a possible initiating and perpetuating stimulus for a proteolytic activation cascade, which may contribute to loosening of the prosthesis.

In vivo corrosion of cobalt-chromium and titanium wear particles

Tissue reaction to wear particles from metal implants may play a major role in the aseptic loosening of implants. We used electron microprobe elemental analysis to determine the chemical composition of wear particles embedded in the soft tissues around hip and knee implants from 11 patients at revision surgery for aseptic loosening. The implants were made of cobalt-chromium-molybdenum alloy or titanium-aluminium-vanadium alloy. Histological examination showed a widespread giant-cell reaction to the particles. Elemental analysis showed that the chemical composition of the particles was different from that of the implanted alloys: cobalt and titanium were reduced, often down to zero, whereas chromium and aluminium persisted. Our findings indicate that corrosion is continually changing the shape, size and chemical composition of the implanted alloy. This may alter the biochemical environment of the tissue surrounding an implant to favour bone resorption.

Isolation and characterization of wear particles generated in patients who have had failure of a hip arthroplasty without cement

Wear particles from thirty-five membranes obtained during revision hip-replacement operations were studied after digestion of the soft tissue with papain. The particles were isolated and were characterized with use of light and scanning electron microscopic techniques, x-ray microanalysis, and an automated particle analyzer. The mean size of the polyethylene particles was 0.5 micrometer, and the metal particles were a mean of 0.7 micrometer, as determined with scanning electron microscopy. The automated particle analyzer revealed a mean particle diameter of 0.63 micrometer (more than 90 per cent of all particles were less than 0.95 micrometer) and a mean of 1.7 billion particles per gram of tissue, compared with only 143 million per gram of tissue for the control samples. X-ray microanalysis revealed metal debris in sixteen (46 per cent) of the thirty-five membranes after digestion. Thirteen (50 per cent) of the twenty-six membranes surrounding a titanium-alloy stem contained metal particles, compared with three of the nine membranes surrounding a chromium-cobalt stem. Metal debris was present in only one of the twelve membranes surrounding a titanium-alloy stem without a porous coating, compared with twelve of the fourteen membranes surrounding a titanium-alloy stem with a porous coating. This tenfold difference in prevalence was significant (p < 0.005). On the average, the total number of particles (expressed in millions per gram of tissue) associated with the bipolar acetabular components was twice that associated with the fixed acetabular components. In addition, there was a trend toward a larger mean size of the polyethylene particles in association with the bipolar cups. Our data indicate that particulate prosthetic debris in the tissues around failed femoral components that have been inserted without cement constitutes a class of particles that are predominantly less than one micrometer in size and are present in amounts of more than one billion particles per gram of tissue. Routine histological methods did not detect this class of wear debris and led to a gross underestimation of the amount of debris in these membranes.

Cathepsin G and alpha 1-antichymotrypsin in the local host reaction to loosening of total hip prostheses

The tissue localization and content of the proteolytic enzyme cathepsin G and its inhibitor alpha 1-antichymotrypsin were studied in the local host reaction to loosening of total hip-replacement prostheses in eleven patients and were compared with those in samples of non-inflammatory tissue from the synovial capsule obtained during arthroscopies of the knee. Immunostaining demonstrated cellular localization of cathepsin G in 71 per cent of monocyte or macrophage-like cells and in 46 per cent of fibroblast-like cells in the samples of interface tissue between the bone and the loose acetabular component obtained at the time of the total hip replacements, and in 59 and 42 per cent, respectively, in the samples of pseudocapsular tissue obtained at the same time, whereas the synovial lining cells in the samples of non-inflammatory tissue from the synovial capsule revealed only a slight immunoreactivity to cathepsin G. Cathepsin-G activity was also measured with synthetic succinyl-alanine-alanine-proline-phenylalanine-paranitroanilide as a substrate, the degradation of which was monitored spectrophotometrically. In accordance with results from immunohistochemical studies, cathepsin-G activity was found in the samples of interface tissue (31.6 international units per liter) and the samples of pseudocapsular tissue (15.5 international units per liter) obtained during the total hip replacements, whereas the level of cathepsin-G was low in the samples of non-inflammatory synovial capsular tissue (2.5 international units per liter). Cathepsin-G activity in the samples of pseudosynovial fluid obtained at the time of the total hip replacements was low (2.4 international units per liter), although immunoblot analysis showed marked immunoreactive cathepsin G in the samples of pseudosynovial fluid. This low activity of cathepsin G might be explained by the presence of alpha 1-antichymotrypsin, which was detected by laser nephlometric immunoassay and immunoblot analysis. These results demonstrate increased concentration of cathepsin G locally in the tissues around loose total hip-replacement prostheses. Because cathepsin G is not only able to act on extracellular matrix components (such as gelatin, proteoglycan, elastin, and laminin) at a physiological pH but also is able to activate collagenase, gelatinase, and stromelysin proenzymes, to inactivate tissue inhibitor of metalloproteinases, and to modulate tumor necrosis factor-alpha, it may play an important role in the degradation of periprosthetic connective tissue and in the lysis of bone around the implant, thus contributing to the loosening of prostheses.(ABSTRACT TRUNCATED AT 250 WORDS)

Morphometric and microanalytical analyses of alumina wear particles in hip prostheses

We analysed tissues harvested during 24 retrievals of hip joint prostheses, with one or both articular components made of alumina. We describe the morphology of wear particles, measure their size and analyse their chemical composition. We relate histopathological aspects to the parameters that characterize ceramic wear particles, and notice that tissue reaction relates to the physical aspect and amount of wear debris and does not necessarily depend on their chemical composition.

Dialysis arthropathy of the hip

Beta 2-microglobulin amyloid deposition is associated with a destructive arthropathy in the hip of chronic hemodialysis patients. Twenty-five hips from 18 patients were assessed for the presence and immunohistochemical type of amyloid. The hemodialysis group was compared with an age- and disease-matched control group that had no evidence of renal failure. Beta 2-microglobulin amyloid deposits were present in all patients who had been on hemodialysis for 18 months or more. Beta 2-microglobulin amyloid deposits were not found in patients who had been on hemodialysis for less than 18 months. Amyloid deposits were seen first in the articular cartilage and later involved the synovial membrane, joint capsule, and subchondral bone as well. The presence and amount of amyloid deposition correlated to the duration of hemodialysis. Severely affected hip roentgenographically had a concentric loss of joint space, periarticular erosions, and cystic lesions in the femoral head and acetabulum. These pathologic and roentgenographic changes suggest that amyloid deposition leads directly to the erosive hip arthropathy occurring in hemodialysis patients.

Bone mineral density of the hip and of the anteroposterior and lateral dimensions of the spine in men with rheumatoid arthritis. Effects of low-dose corticosteroids

OBJECTIVE

To assess bone mineral density (BMD) in men with steroid-treated rheumatoid arthritis (RA).

METHODS

Dual-energy x-ray absorptiometry (DXA) was used to measure BMD in 40 men with RA, 20 of whom were receiving low-dose corticosteroids (< or = 10 mg prednisolone daily), and in 20 healthy, age-matched male controls.

RESULTS

BMD was significantly reduced at the femoral neck and greater trochanter in both groups of RA patients, and at the spine from the anteroposterior dimension in the steroid-treated group.

CONCLUSION

Low-dose steroid therapy may induce excess axial osteopenia in men with RA.

Size of metallic and polyethylene debris particles in failed cemented total hip replacements

Reports of differing failure rates of total hip prostheses made of various metals prompted us to measure the size of metallic and polyethylene particulate debris around failed cemented arthroplasties. We used an isolation method, in which metallic debris was extracted from the tissues, and a non-isolation method of routine preparation for light and electron microscopy. Specimens were taken from 30 cases in which the femoral component was of titanium alloy (10), cobalt-chrome alloy (10), or stainless steel (10). The mean size of metallic particles with the isolation method was 0.8 to 1.0 microns by 1.5 to 1.8 microns. The non-isolation method gave a significantly smaller mean size of 0.3 to 0.4 microns by 0.6 to 0.7 microns. For each technique the particle sizes of the three metals were similar. The mean size of polyethylene particles was 2 to 4 microns by 8 to 13 microns. They were larger in tissue retrieved from failed titanium-alloy implants than from cobalt-chrome and stainless-steel implants. Our results suggest that factors other than the size of the metal particles, such as the constituents of the alloy, and the amount and speed of generation of debris, may be more important in the failure of hip replacements.

Cobalt-alloy metal debris in periarticular tissues from total hip revision arthroplasties. Metal contents and associated histologic findings

To investigate the hypothesis that an association exists between the presence of metallic particulate or ionic debris released from the components of a total hip replacement and the histologic reaction in the surrounding tissues, cobalt, chromium, nickel, and molybdenum levels were measured in periarticular tissue from 22 individuals who had revision surgery. Total tissue content of the four elements (averaged per case) ranged from 2.7 to 250 micrograms of metal per gr of dried tissue (mean, 39 micrograms/gr); however, within each case, the tissue-metal content varied more widely. The highest total tissue-metal contents occurred in cases revised for infection. Fibrosis, histiocytic reaction, hemorrhage, and necrosis were the most frequent histologic findings. Polyethylene and cement particles each appeared in approximately half of all sections, while microscopic metal particles were seen only in tissues from the infected hips. Tissue-metal content did not correlate with the histologic findings, with any of the demographic variables, nor with duration of implantation. Ratios of the individual constituent elements generally reflected the cobalt-chromium alloy composition, suggesting that metal debris was present predominantly as wear particles. Only for tissues with very low metal contents did departures of these ratios indicate the presence of ionic corrosion products. The extremely low metal contents measured in many cement-bone interfacial tissues and the few metal particles found histologically suggest that metal particles may have been less important in inflammatory reaction and loosening than cement or polyethylene particles.(ABSTRACT TRUNCATED AT 250 WORDS)

Proteoglycan alterations during developing experimental osteoarthritis in a novel hip joint model

Degenerative hip joint disease was induced in dogs by extra-articular surgery that created a condition that mimics hip dysplasia. Decreased acetabular coverage of the femoral head gave altered mechanical load, with ensuing cartilage degeneration. For comparison, degenerative knee joint disease was induced in other dogs by transection of the anterior cruciate ligament of the knee. The femoral head articular cartilage showed macroscopic signs of degeneration within a month. No macroscopical changes of synovitis were present. Chemical analysis of cartilage samples showed loss of proteoglycans. Guanidine hydrochloride extracts of the cartilage contained proteoglycan fragments that could be separated by equilibrium density gradient centrifugation in cesium chloride. The data indicate that proteoglycans are fragmented by proteolytic cleavage and lost from the cartilage. The proteoglycans remaining in the tissue are smaller and have lost the ability to aggregate with hyaluronic acid. Similarly, in experimental knee joint osteoarthritis, the proteoglycan content of the cartilage decreased. The structural changes of those proteoglycans remaining were of a different nature, with no changes in proteoglycan size or aggregation properties, possibly indicating that both degradation and repair took place in the knee articular cartilage and/or that fragments were rapidly lost from the tissue. This may follow from different surgical procedures, only the one used for the hip joint being extra-articular, or from the different anatomy and physiology of the hip joint and the knee joint.

Comparative investigations of regional lymph nodes and pseudocapsules after implantation of joint endoprostheses

Morphological alterations of pseudocapsules and regional lymph nodes were studied by light and electron microscopy and by Laser Microprobe Mass Analysis (LAMMA). The tissue specimens originated from 32 autopsies of patients with hip joint endoprostheses (time in situ: 3 weeks - 15 years, average: 6 years) and two cases with knee joint endoprostheses. Characteristic changes of the lymph nodes as well as of the pseudocapsules consisted in an infiltration by monocytic histiocytes with various intracytoplasmatic wear particles. The foreign material consisted mainly of the components of bone cement: polymethylmethacrylate (PMMA) and zirconium oxide, to a lesser degree of polyethylene from the articulating surfaces. In two cases with special types of prostheses ceramic or metallic wear particles could be detected too. Most of the wear particles were found in the ipsilateral parailiac lymph nodes and in the paraaortic lymph nodes bilaterally. In the cases with mostly stable prostheses small amounts of wear particles were found in the lymph nodes as soon as 1.5 years after insertion and their number increased in all groups of lymph nodes after longer duration of the implant. The phagocytosing histiocytes showed degenerative changes. At present it is not clear, if the cell damage is caused by the amount of phagocytosed wear particles alone or if specific toxic effects of certain substances are of importance.

Histologic, biochemical, and ion analysis of tissue and fluids retrieved during total hip arthroplasty

Large amounts of metal and polyethylene debris and high ion readings are found in capsule and fibrous membranes of both loose titanium and cobalt-chromium stems. Prostaglandin E2, interleukin-1, and collagenase levels are elevated when compared to control values with collagenase having the highest and most consistent elevations. Synovial fluid and blood ion readings were elevated in loose cemented and cementless stems made from both materials. Blood ion readings were not elevated in fixed stems. Fixed stems had much less particulate debris in soft tissues. The data showed that failure of most metal hip stems was initially due to a mechanical cause, with high debris and ion counts occurring secondarily in capsule and fibrous membranes. Particulate debris and high ion readings are primarily a focal problem contained by the periprosthetic fibrous connective-tissue encapsulation within the femoral canal and joint capsules. No systemic problems were manifest in any of the patients examined and followed in this study.