Weight-bearing Bones Research Articles

Fibrous dysplasia around the elbow

First named by Lichtenstein in 1938, fibrous dysplasia is a noninherited, skeletal developmental abnormality that commonly presents in adolescents and young adults. Normal marrow and cancellous bone are replaced and weakened by immature woven bone and a dense fibrotic stroma containing a disorganized matrix of bony trabecular spicules. Fibrous dysplasia accounts approximately for 5% to 7% of benign bone tumors. It may be monostotic, accounting for 70% to 80% of cases, or polyostotic. Fibrous dysplasia frequently occurs in the ribs, femur, tibia, skull, pelvis, spine and shoulder. Within the long bones, the lesions are predominately diaphyseal, with an epiphyseal lesion rarely occurring. Radiographically, they are classically described by their ‘‘ground glass’’ appearance because they are well circumscribed, radiolucent lesions with a hazy quality to them. These lesions compromise the structural integrity of the involved bone and may lead to a bowing deformity in weight-bearing bones, hence the ‘‘shepherds crook’’ deformity describing coxa vara in the femur. Surgical treatment of fibrous dysplasia is palliative, the main goals being to limit pain and deformity and prevent pathologic fracture. Fractures through a lesion often heal without difficulty but are susceptible to repeat fracture because of the dysplastic nature of the bony callus that forms. Indications for surgery include nonunion, progressive deformity, or persistent pain. Surgical options include curettage and bone grafting (either cortical or cancellous), open reduction and internal fixation (ORIF), and vascularized bone grafts.

The Effect of Nicotine on Distraction Osteogenesis: An Experimental Study on Rabbits

Tobacco smoke contains more than 4,000 constituents, but not all of them are reported to have adverse effects on bone healing after distraction osteogenesis. No research on the systemic administration of nicotine has been done on distraction osteogenesis of the weight-bearing long bones of the lower extremity. Fourteen New Zealand white male rabbits underwent distraction osteogenesis on the right tibia and lengthening by 1 cm. Transdermal nicotine bands were applied onto the dorsal skin of the rabbits in the study group. Mineral density of the distraction zone was measured at weekly intervals using quantitative computerized tomography. Mechanical properties were assessed by torsional loading, and the regenerated bone tissue was subjected to histopathological examination. Comparisons of weekly measurements in both groups showed that while the increase in bone density in the nicotine group was higher, relative to the initial values, it was still far behind the average density obtained in the control group at the end of the experiment. Statistical analysis of mechanical data showed significant differences in the gradient of the regression lines and maximum torsional angles between the two groups. The histopathological assessments showed noticeable neovascularization in the study group, which was concluded to be a compensatory mechanism for the negative delaying effect of nicotine on bone healing. Systemic administration of nicotine can cause delays in the process of healing in distraction osteogenesis by its negative effect on the mineralization of the regenerate. Patients should be made aware of this negative impact of nicotine before the limb-lengthening surgery.

The daily habitual in vivo strain history of a non-weight-bearing bone

Daily mechanical loading strongly influences the architecture and composition of bone tissue. Throughout the day, the amplitudes, rates, frequencies, and the dispersion over time of these loads vary. Nevertheless, most experimental and descriptive studies on the aforementioned relationship consider only cyclic loading and, in addition, focus on weight-bearing bones. A more complete assessment of the daily loading of bone might lead to a better understanding of the natural everyday stimulus for bone maintenance or adaptive responses. In the present study, we measured the daily habitual strain history of the non-weight-bearing mandible bone in the rabbit. Long-term continuous strain recordings were made using an implantable telemetry device able to read out bone-bonded strain gauges. The lateral surface of the rabbit mandibular corpus was chosen as the bone surface of interest. During the recordings, which lasted up to 33 h, the rabbits ( N = 7) were able to move unrestrictedly in their cages, performing their habitual behaviours. Analysis of the recordings revealed that the measured bone surface was subjected to 2.9 (± 1.4) × 10 3 strain events per hour of which 1.8 (± 1.0) × 10 3 had amplitudes ≤ 10 microstrains (μɛ). Larger strain amplitudes occurred less often and principal strains fell within the range of −517 (± 118) μɛ to 298 (± 81) μɛ. Strain rates never exceeded 10,000 μɛ/s and only 8.9% (± 7.2%) of the habitual strain rates were higher than 1000 μɛ/s. Strain frequency spectra displayed clear peaks at 4–5 and 9 Hz. The wirelessly recorded daily strain history of the rabbit mandible featured peak strain amplitudes resembling those of other mammalian mandibles, but much smaller than those found in many long-bone strain measurements.

Distraction osteogenesis induces endothelial progenitor cell mobilization without inflammatory response in man

IntroductionDistraction osteogenesis (DO) is a unique postnatal bone formation process, which is characterized by a profuse increase in vascularization. Recently endothelial progenitor cells (EPCs) have been reported to circulate in substantial numbers under physiologic conditions and to contribute to bone regeneration. The authors investigated EPC mobilization in patients undergoing limb lengthening. Materials and methodsThirteen of 24 consecutive patients who underwent limb-lengthening procedures on weight-bearing long bones (femur and tibia) were included in this study. Peripheral blood samples were taken at four different time points from each patient, that is, before operation (pre-Op), 2 or 3 days after osteotomy (early-PO), before the start of distraction (pre-Dist), and at 7 to 14 days after the start of distraction (during-Dist). Numbers of leukocytes and levels of plasma C-reactive protein (CRP) were determined. After isolating mononuclear cells (MNCs) by centrifugation, we performed FACS analysis on freshly isolated MNCs using antibodies to the cell surface markers; CD34, CD133, vascular endothelial growth factor receptor 2 (VEGFR2), and alkaline phosphatase. MNCs were also cultured in endothelial cell growth medium and numbers of EPC colony-forming units were counted. Plasma levels of EPC-mobilizing cytokines, such as, VEGF, SDF-1, and MCP-1, were determined by ELISA. ResultsNumbers of leukocytes and CRP plasma levels increased significantly during the early-PO period (p<0.01) but were maintained within normal range in the during-Dist period. FACS analysis of freshly isolated MNCs showed that EPC-enriched cell fractions increased after distraction, but that alkaline phosphatase-positive cell numbers were unchanged. Numbers of EPC colony-forming units significantly increased in the during-Dist period (p<0.01). Plasma levels of VEGF and SDF-1 significantly increased in the during-Dist period (p<0.05). In femoral lengthening patients whose healing index was less than 30 days/cm, the number of CFUs was 46.8 in the during-Dist period, whereas it was 12.7 in patients whose healing index was more than 30 days/cm (p=0.088). ConclusionsThis study demonstrates a mobilization of EPC population during distraction osteogenesis in human limb-lengthening patients. Distraction strain provoked increases in the plasma levels of EPC-mobilizing cytokines, such as, VEGF and SDF-1. These findings suggest a possibility that therapeutical approaches which modulate EPC mobilization may speed bone healing by angiogenesis–osteogenesis coupling during distraction osteogenesis.

Reconstruction of a Massive Femoral Bone Defect Using a Double-barreled Free Vascularized Fibular Bone Graft After Wide Resection of Femoral Chondrosarcoma

Salvaging the limb after malignant bone tumor ablation is a tough challenge for a reconstructive surgeon confronting such extensive bone defects. A 40-year-old male without any underlying disease was incidentally diagnosed with a chondrosarcoma over his left femoral bone. An orthopedic surgeon did a wide resection of the malignant bone tumor, leaving a massive bone defect about 11.3 cm in length. A double-barreled free vascularized fibular bone was designed to reconstruct the femoral bone defect. The maximal fibular bone graft harvested was 19 cm long; after the osteotomy, one barrel was 11 cm and the other was 8 cm. An iliac crest cancellous bone graft was harvested to fill the residual space. The pathology report showed a grade 1 well-differentiated conventional chondrosarcoma, and further adjuvant therapy was not suggested. At a 3-year follow-up, plain radiography showed a good bony union of the graft, and the patient could easily tolerate daily activity. A vascularized double-barreled fibular graft is an ideal option for reconstructing a massive defect in weight-bearing bone: it provides not only sufficient mechanical strength but also good union for early rehabilitation. We describe the long-term results after reconstruction and provide a literature review of long-bone chondrosarcoma.

Principles of the therapy of bone infections in adult extremities : Are there any new developments?

Septic diseases of the bone and immediately surrounding soft tissues can be differentiated into osteitis or osteomyelitis. Both are a most serious diagnosis in modern traumatology and orthopaedic surgery. The basis for treatment is a highly specific, problem-adapted therapy with a defined strategy, the paramount goal being to preserve the stable weightbearing bones, maintain a good mechanical axis with correctly working muscles and joints, and avoid permanent disability. “State-of-the-art” therapy of osteitis and osteomyelitis has two priorities: (a) Eradication of the infection; (b) Reconstruction of bone and soft tissue. Surgical treatment with resection of the affected bone segments and soft tissue, followed by reconstructive methods continues to be the main basic therapy, and is supported by local and systemic antibiotics and adjuvant methods such as hyperbaric oxygen. This article provides an overview of the diagnostic features and different surgical procedures as well as the current literature in order to reach the above named goals.

DNA Preservation in Skeletal Elements from the World Trade Center Disaster: Recommendations for Mass Fatality Management*,†

The World Trade Center (WTC) victim identification effort highlights taphonomic influences on the degradation of DNA from victims of mass fatality incidents. This study uses a subset of the WTC-Human Remains Database to evaluate differential preservation of DNA by skeletal element. Recovery location, sex, and victim type (civilian, firefighter, or plane passenger) do not appear to influence DNA preservation. Results indicate that more intact elements, as well as elements encased in soft tissue, produced slightly higher identification rates than more fragmented remains. DNA identification rates by element type conform to previous findings, with higher rates generally found in denser, weight-bearing bones. However, smaller bones including patellae, metatarsals, and foot phalanges yielded rates comparable to both femora and tibiae. These elements can be easily sampled with a disposable scalpel, and thus reduce potential DNA contamination. These findings have implications for DNA sampling guidelines in future mass fatality incidents.

Imaging bone metastases in breast cancer: techniques and recommendations for diagnosis.

Bone is the most common site of distant metastases from breast carcinoma. The presence of bone metastases affects a patient's prognosis, quality of life, and the planning of their treatment. We discuss recent innovations in bone imaging and present algorithms, based on the strengths and weaknesses of each technique, to facilitate the most successful and cost-effective choice of imaging studies for the detection of osseous metastases. Skeletal scintigraphy (bone scan) is very sensitive in the detection of osseous metastases and is recommended as the first imaging study in patients who are asymptomatic. Radiographs are recommended for the assessment of abnormal radionuclide uptake or the risk of pathological fracture and as initial imaging studies in patients with bone pain. MRI or PET-CT can be considered for cases of abnormal radionuclide uptake that are not addressed by radiography. Osseous metastases can lead to emergent situations, such as spinal-cord compression or impending fracture of a weight-bearing bone, and imaging guidelines are essential for early detection and initiation of appropriate therapy. The imaging method used in non-emergent situations, such as assessment of the ribs, sternum, pelvis, hips, and joints, should be guided by the strengths and limitations of each technique.

Long-term rugby practice enhances bone mass and metabolism in relation with physical fitness and playing position

We attempted to clarify whether rugby was able to enhance bone mineral density (BMD) and content (BMC) of weight-bearing bones by modifying bone remodelling in relation to physical fitness in male rugby players compared to controls. 22 male international rugby players aged 20-31 years (forwards, n = 12 and backs, n = 10) were compared to 14 age-matched controls of the same ethnic origin aged 21-33 years. BMD and BMC were measured by DEXA and bone metabolism was evaluated by specific makers. Physical fitness level was analysed in parallel. Both forwards and backs exhibited significantly higher BMD (+15%, +6%, respectively) and BMC (+36%, +18%, respectively) for whole body and all examined sites, regions and segments than controls, with more pronounced difference at forwards. The difference between both groups of rugby players and controls noted for BMD became more pronounced for BMC (+52% for lower limbs). BMD and BMC values were higher in forwards than backs at total body (+9, +16%) and at stressed sites such as spine (+12%, +13%), pelvis (+10%, +11%), upper (+17% for BMC) and lower limbs (+9%, +18%). Athletes, especially forwards, presented higher concentrations of OC and CTX resulting in positive values of the uncoupling index. Total body lean mass as well as muscular strength strongly correlated with total and stressed regional sites such as spine, pelvis, and lower limbs BMD and BMC (r = 0.59, p < 0.01 to r = 0.84, p < 0.001). Similarly, OC, but not CTX, is highly correlated with the same regional and total BMD and BMC (r = 0.67 to r = 0.81, p < 0.001). Rugby participation is associated with improved physical fitness, enhanced axial and appendicular bone mass and increased bone turnover in adult athletes. Moreover, the positive bone adaptation of these athletes may be related to an increase of bone remodelling rate in favour of bone formation, especially in forwards.

Diffuse osteopenia and myelopathy in a puppy fed a diet composed of an organic premix and raw ground beef

An 8-month-old Shetland Sheepdog was evaluated because of the sudden onset of signs of neck pain, collapse, and inability to rise. A cursory diet history indicated that the dog had been fed a raw meat-based diet. Initial evaluation of the dog revealed small physical stature, thin body condition, and signs of cranial cervical myelopathy. Radiographically, diffuse osteopenia of all skeletal regions was identified; polyostotic deformities associated with fracture remodeling were observed in weight-bearing bones, along with an apparent floating dental arcade. Hypocalcemia and hypophosphatemia were detected via serum biochemical analyses. The dog's diet was imbalanced in macronutrients and macrominerals. The dog received supportive care and treatment of medical complications; neurologic abnormalities improved rapidly without intervention. Dietary changes were implemented during hospitalization, and a long-term feeding regimen was established. Following discharge from the hospital, exercise restriction was continued at home. Serial follow-up evaluations, including quantitative bone density measurements, revealed that dietary changes were effective. After 7 months, the dog was clinically normal. In the dog of this report, vitamin D-dependent rickets type I and suspected nutritional secondary hyperparathyroidism developed following intake of a nutritionally incomplete and unbalanced diet. The raw meat-based, home-prepared diet fed to the dog was not feed-trial tested for any life stage by the Association of American Feed Control Officials, and its gross nutrient imbalance induced severe metabolic, orthopedic, and neurologic abnormalities. Inadvertent malnutrition can be avoided through proper diet assessment and by matching nutrient profiles with patients' nutritional needs.

A Novel Strategy Incorporated the Power of Mesenchymal Stem Cells to Allografts for Segmental Bone Tissue Engineering

Mesenchymal stem cells (MSCs) hold great promise for bone regeneration. However, the power of mesenchymal stem cells has not been applied to structural bone allografts in clinical practice. This study designed a new strategy to enhance the efficiency of allografts for segmental bone regeneration. Isolated MSCs were cultured to form a cell sheet. The MSC sheet was then wrapped onto structural allografts. The assembled structures were cultured in vitro to evaluate the differentiation potential of MSC sheet. The assembled structures were implanted subcutaneously into nude mice as well as into the segmental radius defect of rabbits to investigate the efficiency of MSC sheets to repopulate allografts for bone repair. MSC sheets, upon assembling on bone grafts, showed similar differentiation properties to the in situ periosteum in vitro. After implantation the MSC sheets accelerated the repopulation of bone grafts in nude mice. Moreover, MSC sheets induced thicker cortical bone formation and more efficient graft-to-bone end fusion at the segmental bone defects in rabbits. This study thus presented a novel, more efficient, and practical strategy for large weight-bearing bone reconstruction by using MSC sheets to deliver large number of MSCs to repopulate the bone allografts.

Strategies for the analysis of osteitic bone defects at the diaphysis of long bones.

Septic diseases of the bone and the immediate surrounding soft tissue, i.e., osteitis, belong to the most alarming findings in recent traumatology and orthopedic surgery. The paramount goal of this therapy is to preserve the stable weight-bearing bones while maintaining a correct axis and proper working muscles and joints, in order to avoid permanent disability in the patient. “State-of-the-art” therapy of osteitis/osteomyelitis therapy has two priorities: eradication of the infection and reconstruction of bone and soft tissue. Surgical treatment of the affected bone segments and soft tissue, followed by reconstructive methods, continues to be the main basic therapy. It is often extremely difficult to decide whether the affected bone segment has to be resected, or whether bone continuity can be preserved. The following paper provides strategies and guidance to help guide decisions in this complex and challenging area.

Image-Guided Ablation Therapy of Bone Tumors

A wide range of thermal and cryoablation methods is currently available for the curative eradication or palliative treatment of a variety of bone and soft-tissue tumors. Radiofrequency ablation has been developed as a multipurpose tool for the skeletal system. Cryoablation has the added advantages of direct computed tomography or magnetic resonance visualization and monitoring of treatment outcome with less peri- and postoperative pain. Use of appropriate thermo-sensors and insulation techniques, like carbon dioxide insufflation, results in enhanced safety and efficacy. Ablation of weight-bearing bones has to be supplemented with cement consolidation. The authors present an overview of the current status of percutaneous image-guided ablation therapy of bone and soft-tissue tumors, analyze the merits and limitations of the various systems available, and discuss possible new applications for the future.

Effect of body fat stores on total and regional bone mineral density in perimenopausal Chinese women

Accumulation of body fat is known to be beneficial to bone mass through increased body weight. However, not all the skeleton is loaded by body weight. Therefore, we assume that fat stores would exert different effects on bone mass at different skeletal sites. In this study, 84 perimenopausal Chinese women were recruited. Using dual-energy X-ray absorptiometry, total body fat mass (TBFM), total body lean mass (TBLM), percent body fat (PBF), and total body and regional bone mineral density (BMD) were measured. Correlation analysis indicated that PBF correlated negatively with BMD at ribs and both arms (all P < 0.05). After adjusting for TBLM, PBF had a significantly negative correlation with BMD at head, ribs, both arms, and whole body (all P < 0.05). With adjustment for body weight and height, a significantly negative correlation between PBF and BMD was present, not only at ribs and arms but also at legs and whole body (all P < 0.05, except right leg, at P = 0.094). There was a significantly positive correlation between body weight and leg BMD (all P < 0.001). Body weight was positively correlated with TBFM (r (2) = 0.783, P < 0.001) and TBLM (r (2) = 0.770, P < 0.001). Based on the results, we conclude that increased body fat stores would exert a detrimental effect on BMD, but this effect is more prominent on non-weight-bearing bone. On weight-bearing bone, the detrimental effect of increased body fat could be offset or outweighed by the beneficial effect of increased body weight.

Making no Bones About it: Bone Mineral Density Changes Seasonally in a Nonhibernating Alaskan Rodent

High-latitude voles and lemmings undergo strong seasonal changes in their behavior and physiology, which may lead to concurrent changes in bone mineral density (BMD). We tested whether the BMD of northern red-backed voles (Myodes rutilus) in Alaska changed seasonally, and if so, whether these changes in their weight-bearing bones were correlated with seasonal changes in photoperiod (a mediator of activity and concentrations of reproductive hormones in high-latitude voles and lemmings), body mass, body length, or a combination of these. We used dual-energy X-ray absorptiometry to measure the BMD of the femur and humerus of voles collected in different seasons. BMDs increased dramatically from the start of spring to their peak level in early summer, and then decreased gradually to their lowest point in late winter. BMDs were significantly lower in fall and winter than in spring and early summer. BMDs of long bones were significantly correlated with both body mass and photoperiod, which accounted for 46.2% and 45.7% of the variation in the BMDs of femur and humerus, respectively. The strong changes that we observed in BMD are likely to be due, in part, to the combined effects of strong seasonal changes in body mass, activity, and baseline levels of reproductive hormones.

Reconstruction of irradiated bone segmental defects with a biomaterial associating MBCP+®, microstructured collagen membrane and total bone marrow grafting: An experimental study in rabbits

The bone tissue engineering models used today are still a long way from any oncologic application as immediate postimplantation irradiation would decrease their osteoinductive potential. The aim of this study was to reconstruct a segmental critical size defect in a weight-bearing bone irradiated after implantation. Six white New Zealand rabbits were immediately implanted with a biomaterial associating resorbable collagen membrane EZ(R) filled and micro-macroporous biphasic calcium phosphate granules (MBCP+(R)). After a daily schedule of radiation delivery, and within 4 weeks, a total autologous bone marrow (BM) graft was injected percutaneously into the center of the implant. All the animals were sacrificed at 16 weeks. Successful osseous colonization was found to have bridged the entire length of the defects. Identical distribution of bone ingrowth and residual ceramics at the different levels of the implant suggests that the BM graft plays an osteoinductive role in the center of the defect. Periosteum-like formation was observed at the periphery, with the collagen membrane most likely playing a role. This model succeeded in bridging a large segmental defect in weight-bearing bone with immediate postimplantation fractionated radiation delivery. This has significant implications for the bone tissue engineering approach to patients with cancer-related bone defects.

Osteocyte-derived HB-GAM (pleiotrophin) is associated with bone formation and mechanical loading

HB-GAM (also known as pleiotrophin) is a cell matrix-associated protein that is highly expressed in bone. It affects osteoblast function, and might therefore play a role in bone development and remodeling. We aimed to investigate the role of HB-GAM in bone in vivo and in vitro.The bones of HB-GAM deficient mice with an inbred mouse background were studied by histological, histomorphometrical, radiological, biomechanical and μ-CT analyses and the effect of immobilization was evaluated. HB-GAM localization in vivo was studied. MLO-Y4 osteocytes were subjected to fluid shear stress in vitro, and gene and protein expression were studied by subtractive hybridization, quantitative PCR and Western blot. Human osteoclasts were cultured in the presence of rhHB-GAM and their formation and resorption activities were assayed.In agreement with previous reports, the skeletal structure of the HB-GAM knockout mice developed normally. However, a growth retardation of the weight-bearing bones was observed by 2 months of age, suggesting a link to physical activity. Adult HB-GAM deficient mice were characterized by low bone formation and osteopenia, as well as resistance to immobilization-dependent bone remodeling. HB-GAM was localized around osteocytes and their processes in vivo and furthermore, osteocytic HB-GAM expression was upregulated by mechanical loading in vitro. HB-GAM did not affect on human osteoclast formation or resorption in vitro. Taken together, our results suggest that HB-GAM is an osteocyte-derived factor that could participate in mediating the osteogenic effects of mechanical loading on bone.

Development of A New Accelerometer-Based Physical Activity-Monitoring System Using A High-Frequency Sampling Rate

Physical activity is known to enhance the mechanical competence of weight-bearing bones, and it is also effective for the prevention of osteoporosis. However, little information is available regarding the optimum exercise and intensity of load to weight-bearing bones as well as about a precise system to monitor the intensity of physical activity. To measure the precise load to weight-bearing bones of exercise as a first step, this study is to evaluate the sampling conditions of data acquisition and develop an accelerometer-based physical activity monitoring and its intensity analysis system. Through a simulation experiment, we found that 1k Hz of sampling rate is possible to achieve a measurement error of less than 2%. With the optimum sampling rate of 1k Hz, we developed an accelerometer-based activity-monitoring system. We then assessed the magnitude of acceleration at the shank, knee, and lumber in healthy subjects (n=19) as they descended stairs. A correlation analysis of the precise acceleration values in three points of the body showed that our system could accurately identify the shock absorptive function of lower extremities. Therefore, we strongly believe that our system, with the optimum sampling rate of 1k Hz, produced an accurate measurement of loads acting on weight-bearing bones.

Percutaneous osteoplasty for painful sternal lesion from multiple myeloma

Percutaneous osteoplasty (POP) as a technical extension of percutaneous vertebroplasty has been used as a treatment for osteolytic lesions in weight-bearing bones besides the vertebrae, and has demonstrated beneficial outcomes in terms of pain relief and functional improvement. However, its efficacy in non-weight-bearing bones is not well known. Herein, we present the case of a patient with an osteolytic lesion from multiple myeloma in the sternum, a non-weight-bearing bone, who obtained sustained pain relief and improvement of life quality after POP. These data suggest that POP may be an alternative treatment for osteolytic lesions in non-weight-bearing bones.

Kontinuitätserhalt oder Segmentresektion

Septic diseases of the bone and immediately surrounding soft tissue (i.e., osteitis) are among the most alarming findings in traumatology and orthopedic practice. The paramount goal is to preserve the stable weight-bearing bones, maintaining a correct axis and proper working muscles and joints, in order to avoid permanent disability in the patient. State-of-the-art therapy for osteitis/osteomyelitis has two priorities: eradication of the infection and reconstruction of the bone and soft tissue. Surgical treatment with resection of the affected bone segments and soft tissue, followed by reconstruction, continues to be the main basic therapy. Deciding whether the affected bone segment must be resected or if bone continuity can be preserved is sometimes very difficult. This article provides strategies and decision-making guidance for this problem.