Scanning electron microscopic study of subchondral bone tissues in osteoarthritic femoral head]

In total hip replacement for 12 aged women with advanced osteoarthritis of the hip joint, three types of lesioned articular cartilage with various degrees of severity and ivory bone were obtained together with their subchondral bone tissues. These specimens were processed and studied under scanning electron microscope and were compared with sex and age-matched non-osteoarthritic femoral head articular cartilage specimens. In osteoarthritic femoral heads, with deepening of the articular lesion, the articular cartilage gradually became thinned out and eventually lost. The subchondral bone plate became markedly thickened in most of the specimens. The epiphyseal trabeculae were also thickened and turned rough so that the meshwork pattern gradually disappeared. The thickened trabeculae finally fused into a large piece of dense bone tissues without microfracture. These changes could be accounted for by the increased stress imposed on the subchondral bone tissues as a result of incompetence of the diseased articular cartilage. Consequently, the changes on the part of subchondral bone tissues of the osteoarthritic femoral heads were the sequent, rather than the cause, of the articular lesions.     

Alterations of the mineralization profile and osteocalcin concentrations in osteoarthritic cortical iliac crest bone

Summary The relation between bone mineralization and osteocalcin content was investigated in iliac crest cortical bone obtained at necropsy in young females and in two groups of elderly women with and without osteoarthritis of the hands evaluated by X-ray. Using density fractionation technique, the bone was separated into fractions of increasing density from 1.72 to 2.30 g/ml. The mineralization profile revealed a significant shift to higher densities in the osteoarthritis cases compared with young adults (P<0.005) and age-sexmatched controls (P<0.001). The ash, calcium, and phosphorus content of the bone increased with increasing density of the fractions whereas collagen content, measured as hydroxyproline, decreased. The osteocalcin concentration of each fraction was determined in the supernatants obtained after EDTA-extraction in the presence of protease inhibitors. In the young control and osteoarthritis group, the osteocalcin content in the lowest density fractions was higher compared with the older non-osteoarthritic group. Osteocalcin content of the high density fractions, representing highly mineralized osteons, was the same in the three groups studied. These findings support the hypothesis that quality differences in bone may explain the inverse relationship between osteoarthritis and osteoporosis.     

Influence of age and gender on microarchitecture and bone remodeling in subchondral bone of the osteoarthritic femoral head

IntroductionAge and gender have been reported to have a remarkable impact on bone homeostasis. However, subchondral bone, which plays a pivotal role in the initiation and progression of OA, has been poorly investigated. This study was to investigate age- and gender-related changes of microarchitecture and bone remodeling in subchondral bone in OA.MethodsSubchondral trabecular bone (STB) and deeper trabecular bone (DTB) specimens were extracted in the load-bearing region of femoral heads from 110 patients with OA. Micro-CT and histomorphometry were performed to analyze microarchitectural and bone remodeling changes of all specimens.ResultsCompared to DTB, STB showed more sclerotic microarchitecture, more active bone remodeling and higher frequency of bone cysts. There were no gender differences for both microarchitecture and bone remodeling in STB. However, gender differences were found in DTB, with thinner Tb.Th, higher Tb.N, higher OS/BV and ES/BV in males. In both STB and DTB, no correlation between microarchitecture and age was found in both genders. However, bone remodeling of STB increased significantly with age in males, while bone remodeling of DTB increased significantly with age in females. No age or gender preference was found in subchondral bone cyst (SBC) frequency. The cyst volume fraction was correlated with neither age nor gender.ConclusionsThere were differences in microarchitecture and bone remodeling between STB and DTB, which may be due to the distinct biomechanical and biochemical functions of these two bone structures in maintaining joint homeostasis. OA changed the normal age- and gender-dependence of bone homeostasis in joints, in a site-specific manner.     

Histomorphometric analysis of vertebral and iliac crest bone samples. A correlated study

Iliac crest and corresponding second vertebral body specimens were obtained from 20 cadavers. Of these, ten underwent histopathologic evaluation and histomorphometry in a blind fashion followed by statistical evaluation of the results. In this study, the authors found the iliac crest biopsy specimens to be highly correlated and predictive of osteoid and resorptive parameters in the spine and less so for trabecular bone volume. Whereas the transileal bone biopsy is a useful tool in diagnosing and typing metabolic bone disease, its predictive value of bone volume at other sites in the skeleton requires further evaluation.     

Elevated cross-talk between subchondral bone and cartilage in osteoarthritic joints

Osteoarthritis (OA) is a degenerative joint disease and one of the leading causes of disability in the United States and across the world. As a disease of the whole joint, OA exhibits a complicated etiology with risk factors including, but not limited to, ageing, altered joint loading, and injury. Subchondral bone is hypothesized to be involved in OA development. However, direct evidence supporting this is lacking. We previously detected measurable transport of solute across the mineralized calcified cartilage in normal joints, suggesting a potential cross-talk between subchondral bone and cartilage. Whether this cross-talk exists in OA has not been established yet. Using two models that induced OA by either ageing or surgery (destabilization of medial meniscus, DMM), we tested the hypothesis that increased cross-talk occurs in OA. We quantified the diffusivity of sodium fluorescein (mol. wt. 376Da), a marker of small-sized signaling molecules, within calcified joint matrix using our newly developed fluorescence loss induced by photobleaching (FLIP) method. Tracer diffusivity was found to be 0.30±0.17 and 0.33±0.20μm(2)/s within the calcified cartilage and 0.12±0.04 and 0.07±0.03μm(2)/s across the osteochondral interface in the aged (20-24-month-old, n=4) and DMM OA joints (5-month-old, n=5), respectively, which were comparable to the control values for the contralateral non-operated joints in the DMM mice (0.48±0.13 and 0.12±0.06μm(2)/s). Although we did not detect significant changes in tissue matrix permeability in OA joints, we found i) an increased number of vessels invading the calcified cartilage (and sometimes approaching the tidemark) in the aged (+100%) and DMM (+50%) joints relative to the normal age controls; and ii) a 60% thinning of the subchondral bone and calcified cartilage layers in the aged joints (with no significant changes detected in the DMM joints). These results suggested that the capacity for cross-talk between subchondral bone and articular cartilage could be elevated in OA. Further studies are needed to identify the direction of the cross-talk, the signaling molecules involved, and to test whether subchondral bone initiates OA development and could serve as a pharmaceutical target for OA treatment. This article is part of a Special Issue entitled "Osteoarthritis".     

Ambulatory in-office anterior iliac crest bone harvesting.

OBJECTIVE: A prospective study was performed to evaluate the harvesting of autologous bone within the private practice environment, using either a power-driven trephine or corticocancellous block harvesting, and to assess the clinical safety, postoperative morbidity, and patient satisfaction associated with this application. STUDY DESIGN: Thirty-nine patients requiring 40 bone harvests from the anterior iliac crest for maxillofacial reconstruction were included for study. The ages ranged from 16 to 73 years (mean 48.4 years). All surgeries were performed by a single surgeon. Patients were recovered and discharged home directly from the office. RESULTS: Forty iliac crest harvests were performed in the private practice venue from 2001 to 2004, 23 by motorized trephine and 17 by open corticocancellous block harvest. No peri-operative complications were encountered. Postoperative questionnaires were returned by 32 patients. Thirty patients reported that they would undergo hip surgery in an ambulatory environment again if required. CONCLUSION: Harvesting of bone from the anterior iliac crest is a safe and predictable surgical procedure for the private oral and maxillofacial surgical practice setting in selected cases, resulting in a low complication rate. Patient acceptance of this surgery in the private practice venue is high.     

Pseudarthrosis repair. Autogenous iliac crest versus femoral ring allograft

Pseudarthrosis repair in the lumbar spine is one of the most challenging problems faced by spine surgeons. Historically high failure rates with posterior repair have led to the use of anterior lumbar interbody fusion with tricortical iliac crest autograft in these difficult cases. More recently, femoral ring allografts packed with autograft bone have been advocated as another method that would decrease donor site morbidity. Two series of patients underwent anterior lumbar interbody fusion with anterior instrumentation to repair pseudarthrosis (Group I, 33 patients with tricortical autogenous iliac crest and Group II, 20 patients with femoral ring allografts). At minimum 2-year followup, there was no difference in fusion rates (Group I, 32 of 33 versus Group II, 20 of 20). Patients in Group I had radiographic fusion develop more rapidly than patients in Group II (12 months versus 18 months), but a significant proportion of patients in Group I (35%) had an average of 2 mm of graft subsidence. Despite excellent fusion rates in both groups, functional outcomes were not as good with only 28% of patients in Group I and 36% of patients in Group II returning to work. Using anterior instrumentation, anterior interbody fusion offers an excellent method to repair pseudarthrosis using femoral ring allografts or autogenous iliac crest. However, femoral ring allografts offer the potential to decrease donor site morbidity, allowing the surgeon to treat multiple spine levels.     

Osteopenia, hematopoiesis, and bone remodelling in iliac crest and femoral biopsies: a prospective study of 102 cases of femoral neck fractures

Cancellous microanatomy, bone remodelling, and hematopoietic tissue were studied in iliac crest and femoral neck biopsies taken intraoperatively in 102 consecutive patients with displaced intracapsular fractures. About half of the femoral biopsies had osteopenia, and most showed replacement of hematopoietic tissue by fat cells, with absence of osteoblasts and osteoclasts. In contrast, most of the iliac crest biopsies showed relatively less decrease in cancellous bone, while hematopoietic tissue and bone remodelling cells were present in approximately 75%. These results indicate that the iliac crest biopsy does not necessarily reflect cancellous microanatomy, hematopoietic tissue, and bone remodelling at other skeletal sites in any given patient.     

Alterations in the collagen framework of osteoarthritic cartilage and subchondral bone

Summary Specimens obtained from human osteoarthritic knee joints and dog knees with experimentally induced osteoarthritis were used to study the collagenous framework of articular cartilage and subchondral bone in relation to osteoarthritic changes using scanning electron microscopy and light microscopy. Degenerative articular cartilage in osteoarthritic joints showed radial orientation of the collagen fibrils, which were usually discernible as fibrillar bundle formations. Cartilage with extensive lesions often showed cleavages or fissures down to the calcified layer. The cartilagenous collagen fibrils in osteoarthritic specimens merged into the subchondral bone plate making the tidemark and the osteochondral junction irregular or obscure. The trabecular orientation of subchondral bone changed with alteration in the articular cartilage and with reactive changes in the subchondral bone, showing the effect of cartilaginous degeneration on its ultrastructure.

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Résumé Des prélèvements obtenus à partir de genoux humains arthrosiques et de genoux de chien porteurs de lésions arthrosiques expérimentales ont permis l'étude de la charpente de collagène du cartilage articulaire et de l'os sous-chondral, par microscopie conventionnelle et par microscopie électronique.Dans les lésions dégénératives, les fibrilles de collagène du cartilage ont une orientation radiale, alors qu'elles sont habituellement groupées en faisceaux. En cas de lésions étendues, le cartilage présente souvent des clivages ou des fissures menant jusqu'aux couches calcifiées. Les fibrilles de collagène du cartilage arthrosique se fondent dans la plaque osseuse souschondrale, rendant la jonction ostéo-cartilagineuse irrégulière ou mal définie.L'orientation trabéculaire de l'os sous-chondral se modifie en fonction de l'altération du cartilage articulaire. Ces modifications réactionnelles montrent que, même au niveau ultrastructural, l'architecture de l'os sous-chondral reflète la dégénérescence cartilagineuse.

     

Complications following iliac crest bone grafting

Avulsion of the anterior superior iliac spine occurred after procurement of bicortical bone grafts from the anterior superior iliac crest area in two patients. The defect in the anterior ilium with a weak spike of bone created a significant stress riser and led to avulsion of the anterior superior iliac spine by the action of the sartorius and tensor fascia lata. Bicortical grafts should be taken from areas as much as 5 cm posterior to the anterior superior iliac spine to avoid this complication.     

In situ fatty acid profile of femoral cancellous subchondral bone in osteoarthritic and fragility fracture females: implications for bone remodelling

We report here differences in the fatty acid profile of cancellous bone matrix, including n-3, n-6, mono- and poly-unsaturated, as well as saturated fats, between femoral heads from female OA (n=8, aged 68-88years), fractured neck of femur (#NOF) (n=19, 67-88years) and autopsy controls (CTRL) (n=4, 85-97years). Femoral heads were collected from individuals undergoing orthopaedic surgery for OA or #NOF; the fatty acid profile of sub-samples from the superior principal compressive and superior principal tensile regions were determined by gas chromatography. A total of 42 individual fatty acids were detected at varying concentrations with significant differences between subchondral bone from OA subjects, subchondral bone from #NOF subjects and subchondral bone from CTRL subjects, as well as between the superior principal compressive and superior principal tensile regions (for saturated fats only). Subchondral bone from OA subjects had higher total n-6 (OA=10.89±3.17, #NOF=11.11±1.83, CTRL=8.32±2.05, p=0.008) and total n-3 (OA=1.34±0.38, #NOF=1.19±0.18, CTRL=1.15±0.48, p=0.011) percentages than subchondral bone from #NOF subjects and subchondral bone from CTRL subjects, and there was no difference in the n-6:n-3 ratio, nor within the percentage of n-9 fatty acids. Arachidonic acid (OA=0.42±0.16, #NOF=0.26±0.06, CTRL=0.28±0.06, p=0.01), and γ-linolenic acid (OA=0.11±0.03, #NOF=0.05±0.02, CTRL=0.04±0.02, p<0.001) were higher in subchondral bone from OA subjects than subchondral bone from #NOF subjects and subchondral bone from CTRL subjects. In conclusion, there is a wide diversity of fatty acids in cancellous bone matrix from the femoral heads of OA and #NOF, suggesting they may have regulatory effects on inflammatory processes, and their metabolites. This article is part of a Special Issue entitled "Osteoarthritis".     

Computerized three-dimensional histomorphometric study of iliac bone in patients with femoral neck fracture

To elucidate the pathology of osteoporosis, we used a computer, to investigate three-dimensional tissue morphometry in biopsied iliac bone specimens from 20 female patients with femoral neck fractures. The 20 fracture patients were divided into two groups according to age: group I, patients below 70 years of age (n=10) and group II, patient 70 years of age or more (n=10). Five patients who also underwent iliac bone biopsy but who did not have fractures served as the control group. We found that the ilium in group I patients was composed of many small thin trabecular structures, while the ilium in group II was composed of only a few broad trabecular structures. The three-dimensional Euler number was small in osteoporosis, suggesting that trabecular connectivity was also diminished and the fractal dimension decreased. This indicated that the trabecular structure had become irregular. These findings indicate that the number of trabeculae appeared to decrease with trabecular blocking due to osteoporotic changes, and, simultaneously with this phenomenon, the which of the individual trabeculae seemed to become thicker in accordance with bone adaptation to mechanical stress.A summary of this paper was reported at the 9th Annual Orthopaedic Research Meeting of the Japanese Orthopaedics Association (October, 1994), and the 3rd Study Meeting of the Japanese Society of Osteoporosis (October, 1994).     

Donor site morbidity in the iliac crest bone graft.

BACKGROUND: Open iliac crest bone grafting is a common surgical procedure with recognized short-term complications. The present paper documents the medium- to long-term complications and level of patient satisfaction following the procedure. METHODS: Seventy-three patients undergoing an open iliac crest bone graft over the past 6 years at Wellington Hospital were retrospectively reviewed. All patients completed a postal questionnaire which assessed their current pain, sensory changes in and below the scar, scar appearance and overall appearance with the bone graft donor site. RESULTS: Sixteen patients (21.9%) reported pain, 11 patients (15%) stated that their scar was sensitive to touch and 19 patients (22%) reported a degree of sensory change below the scar. Six patients (8.2%) felt that the scar appearance was totally unacceptable. Overall satisfaction, however, was high with 70 patients (95.8%) 'fairly satisfied' or 'totally satisfied' with their iliac crest donor site. CONCLUSIONS: Bone grafting from the iliac crest is a relatively benign procedure in terms of patient satisfaction, and the most significant morbidity is pain.     

The cancellous bone of the iliac crest

A study of the thickness and spacing of bony structures in the cancellous bone of the iliac crest. Ground sections of methacrylate-embedded material from 67 normal subjects, from 20 to 90 years of age, were examined. Increasing age is accompanied by an increase in the spacing between the bony structures, but not by any significant reduction in their thickness. The thinnest bony structures appear to be undergoing the most remodelling, as judged by the extent of formation and resorption surfaces.

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Zusammenfassung Die Dicke der Trabekel und die Weite der Markzwischenräume des Hüftbeinkammes wurden bestimmt. Das in Methacrylat eingebettete Material, welches von 67 Normalpersonen im Alter von 20–90 Jahren stammte, wurde geschnitten und untersucht. Bei zunehmendem Alter vergrößert sich der Raum zwischen den Trabekeln, ohne daß jedoch deren Dicke signifikant vermindert wird. Gemessen am Umfang der Bildungs- und Resorptionsoberfläche scheinen die dünnsten Trabekel dem größten Knochenumbau unterworfen zu sein.

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Résumé Une étude de l'épaisseur et de l'espacement des structures osseuses dans l'os d'aspect réticulé du crête iliaque. Les specimens provenant de 67 sujets normaux, ages de 20 à 90 ans, furent enfoncés dans methacrylate et tranches preparés par meulage. L'age croissant est accompagné d'une augmentation de l'espacement entre les structures osseuses, mais pas d'une reduction signifiante de leur épaisseur. Les structures osseuses les plus minces paraissent subir le plus grand remondellage, jugant par l'importance de surfaces de formation et de résorption.

     

The cancellous bone of the iliac crest

A study of the thickness and spacing of bony structures in the cancellous bone of the iliac crest. Ground sections of methacrylate-embedded material from 67 normal subjects, from 20 to 90 years of age, were examined. Increasing age is accompanied by an increase in the spacing between the bony structures, but not by any significant reduction in their thickness. The thinnest bony structures appear to be undergoing the most remodelling, as judged by the extent of formation and resorption surfaces.     

Prospective study of iliac crest bone graft harvest site pain and morbidity

Background contextMorbidity associated with autologous bone graft harvest is an important factor in determining the utility of expensive alternatives such as recombinant bone morphogenic protein. The most frequently reported complication associated with graft harvest is chronic pain.PurposeTo prospectively determine the degree of pain and morbidity associated with autologous iliac crest bone graft harvest and its effect on activities of daily living.Study designProspective observational cohort study.Patient sampleOne hundred ten adult patients undergoing elective posterior lumbar spinal fusion surgery involving autologous iliac crest bone graft harvest.Outcome measuresPatient self-reported Visual Analog Scale (VAS) scores for pain and a study-specific questionnaire regarding activities of daily living.MethodsOne hundred ten patients were prospectively enrolled. Postoperative VAS scores (0–100) for harvest site pain were obtained at 6-week, 6- and 12-month follow-up. Patients completed a 12-month questionnaire regarding the persistence of specific symptoms and resulting limitation of specific activities.ResultsOne hundred four patients were available for 1-year follow-up. Mean VAS pain scores (scale 0–100) at 6 weeks, 6 and 12 months were 22.7 (standard deviation [SD], 25.9), 15.9 (SD, 21.5), and 16.1 (SD, 24.6), respectively. At 12 months, 16.5% reported more severe pain from the harvest site than the primary surgical site, 29.1% reported numbness, and 11.3% found the degree of numbness bothersome, whereas 3.9% were bothered by scar appearance. With respect to activity limitations resulting from harvest site pain at 1 year, 15.1% reported some difficulty walking, 5.2% with employment, 12.9% with recreation, 14.1% with household chores, 7.6% with sexual activity, and 5.9% irritation from clothing.ConclusionsThere is a significant rate of persistent pain and morbidity from iliac crest bone graft harvest when associated with elective spine surgery. Mean pain scores progressively decline over the first postoperative year. Nevertheless, harvest site pain remains functionally limiting in a significant percentage of patients 1 year after surgery. Rates of functional limitation are higher than previously reported and may be because of increased sensitivity of the prospective study design and targeted investigation of these specific symptoms. Validity of these findings is necessarily limited by patient ability to discriminate harvest site pain from alternative sources of back and buttock pain.     

Static histomorphometry of human iliac crest and vertebral trabecular bone: a comparative study.

We recently developed a new, rapid method for conducting static histomorphometry on large histologic sections. This method has now been applied on both iliac crest and lumbar vertebral bone to compare the age-related changes at these two skeletal sites and to investigate the correlation between the histomorphometric measures at the iliac crest and the vertebral body. The material comprised matched sets of unilateral transiliac crest bone biopsies and lumbar vertebral bodies (L-2) from 24 women (19-96 years) and 24 men (23-95 years) selected from a larger autopsy material. Three female subjects (80, 88, and 90 years) had a known vertebral fracture of L-2. The iliac crest biopsies and 9-mm-thick mediolateral slices of half the entire vertebral bodies were embedded in methylmetacrylate, stained with aniline blue, and scanned into a computer with a flatbed image scanner at a high resolution. With a custom-made computer program the following static histomorphometric measures were determined: trabecular bone volume; marrow and bone space star volume; node-strut analysis; trabecular bone pattern factor; trabecular thickness; trabecular number; trabecular separation; and anisotropy of bone and marrow phase. In addition, connectivity density was measured (ConnEulor method). The results showed that the age-related changes in the static histomorphometric measures are generally similar in the iliac crest and the vertebral body, and that these age-related changes are independent of gender. An exception, however, is connectivity density, where the age-related changes are similar for women and men in the vertebral body but significantly different in the iliac crest. Furthermore, the results showed that the histomorphometric measures were weakly intercorrelated between the iliac crest and the vertebral body, despite the generally similar pattern in age-related changes at these two skeletal sites. The highest correlation coefficient was found for trabecular separation (Tb.Sp; r = 0.63). Trabecular bone volume showed a correlation coefficient of r = 0.59. It is concluded that static histomorphometry performed on one skeletal site does not automatically predict static histomorphometric measures at another skeletal site. Therefore, it is recommended that static histomorphometry be performed at the skeletal site of interest-if at all possible.