Protecting human amnion and chorion matrices during processing: Performance enhancement in a diabetic mouse model and human co-culture system.

Recent evidence suggests that protecting human amnion and chorion matrices (HACM) during processing enhances the performance of HACM for wound repair and tissue regeneration. We utilised a diabetic (db/db) delayed wound healing mouse model. Treatment of db/db full-thickness excisional wounds with HACM, processed with a polyampholyte preservative accentuated the proliferative phase of wound healing that decreased the time necessary to heal wounds. Polyampholyte protection improved the preservation of growth factors and cytokines during room temperature storage following E-beam sterilisation and improved its function in wound healing applications. Our findings indicate protected HACM tissue up-regulated MIP2, NF-kB, TNF-α, KI-67, and Arg1 (0.6-fold to 1.5-fold) but those changes were not statistically significant. Immunofluorescent assessment identifying cell activity illustrated an induction of the proliferative phase of wound healing and a switch from an inflammatory macrophage phenotype (M1) to a pro-regenerative macrophage phenotype (M2a). Genomic profiling of 282 genes was performed using Nanostring from co-cultures of human macrophages and fibroblasts. The polyampholyte + HACM-treated group, compared with the HACM or polyampholyte alone groups, had a statistically significant up-regulation (32-368 fold) of 12 genes primarily involved in macrophage plasticity including CLC7, CD209, CD36, HSD11B1, ICAM1, IL1RN, IL3RA, ITGAX, LSP1, and PLXDC2 (adj. p-value < 0.05). The polyampholyte alone group demonstrated statistically significant down-regulation of four genes ADRA2, COL7A1, CSF3, and PTGS2 (adj. p < 0.05). The HACM alone group up-regulated four genes ATG14, CXCL11, DNMT3A, and THBD, but the results were not statistically significant. Biomechanical measurements indicated that wounds treated with polyampholyte-protected HACM had more tensile integrity compared with wounds treated with HACM alone. These findings indicate that better protection of HACM during processing stabilises the HACM matrix, which may lead to improved wound healing outcomes.

Adolescent Hip Dislocation Combined With Proximal Femoral Physeal Fractures and Epiphysiolysis.

BACKGROUND: The risks and long-term effects of acute hip dislocation combined with proximal femoral physeal fractures and epiphysiolysis have been minimally addressed in the literature. This infrequent combination must be understood to avoid the major complications of complete separation of proximal femoral components during attempted reduction and to predict the probable outcome of surgical treatment. METHODS: Medical records and imaging were retrospectively reviewed to identify patients with a diagnosis of severe to complete slipped capital femoral epiphysis (CFE) or proximal femoral epiphysiolysis in association with hip dislocation. The focus included possible anatomic/vascular disruption and their consequences. RESULTS: Twelve patients were identified. Nine dislocations were posterior; 3 were anterior. In 4 patients, the intact proximal femur was dislocated posteriorly. In 3 patients only the femoral neck was reduced, whereas the CFE remained dislocated. In 1 patient percutaneous pinning was done in the dislocated position before closed reduction. The reduction was successful. In 7 patients only the CFE (4 patients) or femoral neck (3 patients) was displaced at the initial presentation in the emergency room. One patient presented with posterior dislocation associated with complete separation of both components. Ten patients underwent open reduction and internal fixation. Two patients had closed reduction. Nine patients developed complete avascular necrosis, progressive collapse of the femoral head, and degenerative arthritis. Three subsequently had a total hip arthroplasty. One patient developed ischemic change limited to the femoral neck and a nonunion through the epiphysis. One patient had incomplete ischemic necrosis. Only 1 patient had no evidence of ischemic necrosis. CONCLUSIONS: This combination of injuries has several anatomic variations. Leaving the CFE dislocated while reducing only the femoral neck must be avoided. Reduction should be done in the operating room with muscle relaxation. The emergency room is not the venue for reduction. The risk of avascular necrosis is extremely high, whether the separation occurs during the acute dislocation or attempted reduction. LEVEL OF EVIDENCE: Level IV-case series (retrospective review).

The Use of Human Amniotic Membrane Tissue Grafting in Acute Traumatic Finger Injury: A Case Report.

Human amniotic membrane (hAM) is a collagen-based extracellular matrix that facilitates regenerative wound care. hAM offers several advantageous properties that promote epithelial cell growth, granulation, and angiogenesis. This case report demonstrates how Vivex Cygnus Matrix (Vivex Biologics, Miami, FL, USA) amniotic membrane was used over four weeks to graft a traumatic index finger injury that occurred while fishing. Cygnus Matrix allograft was first placed 72 hours after the accident. Following graft placement, the patient noted an immediate relief in pain and was able to return to all normal daily work activities within 48 hours of graft placement. Granulation tissue appeared a few days later. A total of four grafts were placed over the course of four weeks starting on September 4th, 2023. Typically, acute traumatic wounds are managed with a regimen of irrigation, wound dressing, and debridement. In this unique case, a distal fingertip amputation was treated with Cygnus Matrix allograft. A single hAM was applied weekly over the course of four weeks. Complete reepithelization of the injury was achieved with minimal scar formation. This paper demonstrates the use of hAM in healing acute traumatic wounds as an effective alternative to other more traditional treatments such as skin grafting, surgical reimplantation, and composite grafting. Utilization of hAM in acute traumatic wounds has few research reports that assure that the applications have minimal drawbacks while at the same time promoting wound management and patient comfort.

Continued growth after limited physeal bridging.

BACKGROUND: After any physeal injury, the primary concern is the possibility of some pattern of growth alteration, particularly transphyseal bridging that may cause lasting deformities and impact subsequent patient care. Small areas of physeal bridging, however, may be associated with continued growth, rather than impairment. METHODS: Seven patients with small central physeal bridges of the distal femur were identified. Demographic data and imaging studies were reviewed. RESULTS: Radiography identified small, relatively centrally located transphyseal osseous bridging that was associated with a linear (longitudinal) region of osseous density extending from the physeal bridge proximally into the metaphysis. This linear striation disappeared at the metaphyseal/diaphyseal gradation, an area of progression proximally from metaphysis to diaphysis. Only 1 patient had a significant leg length inequality. Magnetic resonance imaging confirmed the intrametaphyseal linear sclerotic bone and its disappearance with diaphyseal remodeling. CONCLUSIONS: Small, central transphyseal osseous bridges may form after radiologically confirmed acute physeal injury. Normal physiological (hydrostatic) growth forces can be sufficient to overcome such limited central bridging and allow continued, essentially normal, longitudinal growth. LEVEL OF EVIDENCE: Level IV (retrospective case series); anatomic study.

Guiding bone formation in a critical-sized defect and assessments.

PURPOSE: Development of alternatives to autologous bone has been served by many hypotheses and developments. Favorable properties of synthetic materials used currently in bone grafting support tissue differentiation without shielding capacity for integrated modeling. Ideally, new materials provide tissue compatibility and minimize patient morbidity and are attractive because of potential for in situ delivery, isothermal polymerization, porous structure, and nontoxic chemistry. For application in cranial bone, ability for materials to be laid adjacent to brain and offer postsurgical protection without neural risk is a critical asset. METHODS: Kryptonite Bone Cement (KBC) meets the property criteria for cranial bone repair with regard to adhesive, conductive, and biologic transparency and US Food and Drug Administration approval for cranial bone void repair. To better delineate the morphology effective in cranial bone repair, a comparison was made between KBC and BoneSource, another material approved for the same indication. After Institutional Animal Care and Use Committee approval, the study assessed 24 rabbits, each with 2 separate cranial implants, to evaluate integration and absorption of the biomaterial at defined time points of 12, 18, 24, and 36 weeks. RESULTS: The 36-week assessment demonstrated near-complete resorption/integration of the BoneSource graft material. Bone was present within the biomaterial as well as independent of contact. The KBC was similarly integrated throughout the mass of the material, and new bone was in contact with the grafting material and also seen as separate islands of new bone. The bone demonstrated lamellar bone architecture with clear trabecular morphology. At higher magnification, the bone architecture can be clearly delineated, and comparison between the graft fillers is not obvious relative to the bone that has formed. Despite microscopic similarities, the most striking difference was maintenance of scaffold anatomy during bone regeneration. CONCLUSIONS: Kryptonite Bone Cement meets the criteria described in the introduction; properties of biologic transparency, osteoconductivity, and ergonomic utility offer other potential uses in bone repair. Key tenets of bone tissue regeneration observed in this analysis included adequate cell differentiation and tissue support. Bone that formed demonstrated lamellar rather than woven bone to suggest response to loading strain rather than merely biochemical precipitation. Over the 36-week study, the graft showed progressive bioabsorbable potential with calibrated replacement.

The Relationship between Exosomes and Cancer: Implications for Diagnostics and Therapeutics.

Exosomes are very small extracellular vesicles secreted by cells to local and distant tissues. These mini signal transporters elicit acute and chronic effects on recipient cells. Studies regarding exosomes and their relationship to disease, as well as healthy functions, are eliciting extraordinary excitement as data pours in from groups around the world. Reporting of exosome biogenesis, selective loading of cargo, directed release, and resulting changes in adjacent and distal cells are providing information that is changing the way we view cancer progression and treatment. As a result, the properties of exosomes are being exploited for diagnostic, prognostic, and therapeutic applications. First, by referring to the signaling molecules carried by exosomes, they are being tested as indicators of the presence of transformed cells in early stages of cancer. Secondly, the cargo of exosomes secreted from tumors have been linked to prognostic factors and metastatic properties. Thirdly, exosome-based therapies are being developed which utilize the inherent properties of these mini-transporters to affect and interfere with cancer. Exosome creation, loading, and release plays an important role in cancer formation, progression and organotropic metastasis. The developed and developing therapies should be considered with understanding of their advantages and pitfalls, as well as the various roles exosomes play in normal and pathogenic processes. The combination of previously discovered attributes of exosomes with new discoveries occurring daily provide valuable and additive relevant factors to be considered as we embark on the continued discovery of exosomes and their relationship to cancer diagnostics and therapeutics.

Methods of Cryoprotectant Preservation: Allogeneic Cellular Bone Grafts and Potential Effects.

Debridement of the bone surface during a surgical fusion procedure initiates an injury response promoting a healing cascade of molecular mediators released over time. Autologous grafts offer natural scaffolding to fill the bone void and to provide local bone cells. Commercial bone grafting products such as allografts, synthetic bone mineral products, etc., are used to supplement or to replace autologous grafts by supporting osteoinductivity, osteoconductivity, and osteogenesis at the surgical site. To assure osteogenic potential, preservation of allogeneic cells with cryoprotectants has been developed to allow for long-term storage and thus delivery of viable bone cells to the surgical site. Dimethyl sulfoxide (DMSO) is an intracellular cryoprotectant commonly used because it provides good viability of the cells post-thaw. However, there is known cytotoxicity reported for DMSO when cells are stored above cryogenic temperatures. For most cellular bone graft products, the cryoprotectant is incorporated with the cells into the other mineralized bone and demineralized bone components. During thawing, the DMSO may not be sufficiently removed from allograft products compared to its use in a cell suspension where removal by washing and centrifugation is available. Therefore, both the allogeneic cell types in the bone grafting product and the local cell types at the bone grafting site could be affected as cytotoxicity varies by cell type and by DMSO content according to reported studies. Overcoming cytotoxicity may be an additional challenge in the formation of bone at a wound or surgical site. Other extracellular cryoprotectants have been explored as alternatives to DMSO which preserve without entering the cell membrane, thereby providing good cellular viability post-thaw and might abrogate the cytotoxicity concerns.

Biomechanical Comparison of Fixed- versus Variable-Angle Locking Screws for Distal Humerus Comminuted Fractures.

BACKGROUND: To compare the stability of fixed- versus variable-angle locking constructs for the comminuted distal humerus fracture (AO/OTA 13-A3). METHODS: Eight pairs of complete humeri harvested from eight fresh frozen cadavers were used for the study. We fixed the intact humeri using 2.7-mm/3.5-mm locking VA-LCP stainless steel distal humerus posterolateral (nine-hole) and medial (seven-hole) plates. An oscillating saw was used to cut a 1-cm gap above the olecranon fossa. The specimens were loaded in axial mode with the rate of 1 mm per 10 seconds to failure, and stress-strain curves were compared in each pair. The mode of failure was recorded as well as the load needed for 2- and 4-mm displacement at the lateral end of the gap. RESULTS: The stiffness of the constructs, based on the slope of the stress-strain curve, did not show any difference between the fixed- versus variable-angle constructs. Likewise, there was no difference between the force needed for 2- or 4-mm displacement at the lateral gap between the fixed- and variable-angle constructs. The mode of failure was bending of both plates in all specimens and screw pull-out in four specimen pairs in addition to the plate bending. CONCLUSIONS: Our results did not show any difference in the biomechanical stability of the fixed- versus variable-angle constructs. There was not any screw breakage or failure of the plate-screw interface.

Posterior lumbar interbody fusion using rhBMP-2.

The use of biological technologies for the treatment of degenerative spinal diseases has undergone rapid clinical and scientific development. BMP strategies have gained wide support for an inherent potential to improve the ossification process. It has been extensively studied in combination with various techniques for spinal stabilisation from both anterior and posterior approach. We studied the fusion process after implantation of rhBMP-2 in 17 patients with degenerative lumbar spine diseases in combination with dorsal fixation with pedicle screws and poly-ether-ether-ketone (PEEK) interbody cages. We used 12 mg rhBMP-2 carried by collagen sponge, 6 mg in every cage. Patient follow up consisted of pre-operative radiographic and clinical evaluation. Similar post-operative evaluations were performed at 3 and 6 months. Clinical assessment demonstrated clear improvement in all patients despite evidence of vertebral endplate osteoclastic activity in the 3-month radiographs. The 6-month radiograph, however, confirmed evidence of fusion, and no untoward results or outcomes were noted. While previous studies have shown exclusively positive results in both fusion rates and process, our study demonstrated an intermediate morphology at 3 months during the ossification process using Induct Os in combination with peek-cages using a PLIF-technique. The transient resorption of bone surrounding the peek cage did not result in subsidence, pain or complication, and fusion was reached in all cases within a 6-month-controlled evaluation. Although there was no negative influence on clinical outcome, the potential for osteoclastic or metabolic resorption bears watching during the post-surgical follow up.

Transforaminal Lumbar Interbody Fusion With Viable Allograft: 75 Consecutive Cases at 12-Month Follow-up.

BACKGROUND: When conservative treatments fail to alleviate the discomfort of abnormal motion, spinal fusion has been shown to provide symptomatic treatment for spinal instability, stenosis, spondylolisthesis, and symptomatic degenerative disc disease. The trend and rates of fusion over the past few years have been dramatic in the United States. Accompanying that higher incidence has been the shifting from traditional open surgery to minimally invasive techniques to reduce scar tissue formation, extent of muscle stripping, and muscle retraction which all have been shown to adversely affect outcomes. Other reasons supporting the widespread transition to minimally invasive surgical (MIS) techniques include decreased postoperative pain, decreased intraoperative blood loss, shorter postoperative hospital stay, faster return to normal activity, and reduced reoperation rates. Spinal fusion procedures rely on a bony fusion substrate in addition to fixation hardware. While available grafting options include autogenous, allogeneic, and synthetic materials, recent interest in viable allograft material with living cells has drawn attention and attraction for incorporating a biologic basis for regenerative consideration. A recent viable allograft, complete with cellular and designated bone carrier (VIA Graft, Vivex Biomedical, Marietta, Georgia) has been developed. This study represents a retrospective review of a single-practice, single-surgeon evaluation of the product in 75 consecutive patients for fusion by computed tomography (CT) and radiographic evaluation at 12 months in conjunction with a MIS approach. Viable allograft was used to fill the peri-implant space, and central implant lumen was filled with a cancellous bone sponge soaked in perivertebral bone marrow. Posterolateral supplementation was attained with beta-tricalcium phosphate as a bulking agent. METHODS: A retrospective review identified patients treated for both primary and revision surgery who received VIA Graft cellular bone matrix material in minimally invasive interbody fusion (MIS-TLIF) with a minimum of 12-month follow up. The patient diagnoses included radiculopathy in all instances and varied collateral indications such as foraminal collapse, recurrent disc herniation, and spondylolisthesis to which pain and morbidity had been unresolved by conservative treatment. Adverse events including infection, revisions, and evidence of immune response were evaluated and patient comorbidities defined for the entire population of patients. Patient fusion status was assessed using thin slice CT by 2 independent radiologists separate from the surgeon. There were 75 consecutive adult patients with degenerative conditions of the lumbar spine who underwent MIS-TLIF surgery of which 40 (53%) were male and 35 (47%) were female. Mean age, height, and weight were 58 years, 170.18 cm (67 in), and 88.45 kg (195 lbs), respectively. The mean body mass index was 30. There were 16 patients (21%) who smoked and 12 (16%) with a history of diabetes. Independent blinded review of fusion was obtained by a board certified musculoskeletal radiologist and an experienced board certified orthopaedic surgeon to assess patient fusion status. Spinal segments were deemed fused if 12-month CT scans demonstrated evidence of bridging bone at the fusion site without observed motion on flexion-extension radiographs. Findings such as osteolysis around the implant or pedicle screws, extensive endplate cystic changes, or linear defects parallel to the endplates through intradiscal new bone formation were interpreted as signs of pseudarthrosis. Interobserver and intraobserver error and κ assessments were analyzed to assure agreement in the CT outcomes assessment where interpretation of κ were as follows: <0.00 = poor agreement, 0.00-0.20 = slight agreement, 0.21-0.40 = fair agreement, 0.41-0.60 = moderate agreement, 0.61-0.80 = substantial agreement, and 0.81-1.00 = almost perfect agreement. Differences were resolved by consensus amongst the observers. RESULTS: In total, 96% of the 75 patients with a total of 85 levels (96.5% of levels treated) achieved a fusion at 12 months. There were no perioperative or latent complications and no transfusions in all 75 patients. CONCLUSIONS: In this population, 96% of the patients treated achieved the surgical objective in 96.5% of the levels treated. LEVEL OF EVIDENCE: IV. CLINICAL RELEVANCE: The high rate of fusion, the lack of secondary morbidity with autologous bone harvest, and the clinical success account for the benefits of viable allograft matrix for MIS-TLIF use.

Strains in trussed spine interbody fusion implants are modulated by load and design.

Titanium cages with 3-D printed trussed open-space architectures may provide an opportunity to deliver targeted mechanical behavior in spine interbody fusion devices. The ability to control mechanical strain, at levels known to stimulate an osteogenic response, to the fusion site could lead to development of optimized therapeutic implants that improve clinical outcomes. In this study, cages of varying design (1.00 mm or 0.75 mm diameter struts) were mechanically characterized and compared for multiple compressive load magnitudes in order to determine what impact certain design variables had on localized strain. Each cage was instrumented with small fiducial sphere markers (88 total) at each strut vertex of the truss structure, which comprised of 260 individual struts. Cages were subjected to a 50 N control, 1000 N, or 2000 N compressive load between contoured loading platens in a simulated vertebral fusion condition, during which the cages were imaged using high-resolution micro-CT. The cage was analyzed as a mechanical truss structure, with each strut defined as the connection of two vertex fiducials. The deformation and strain of each strut was determined from 50 N control to 1000 N or 2000 N load by tracking the change in distance between each fiducial marker. As in a truss system, the number of struts in tension (positive strain) and compression (negative strain) were roughly equal, with increased loads resulting in a widened distribution (SD) compared with that at 50 N tare load indicating increased strain magnitudes. Strain distribution increased from 1000 N (+156 ± 415 µÎµ) to 2000 N (+180 ± 605 µÎµ) in 1.00 mm cages, which was similar to 0.75 mm cages (+132 ± 622 µÎµ) at 1000 N load. Strain amplitudes increased 42%, from 346µÎµ at 1000 N to 492µÎµ at 2000 N, for 1.00 mm cages. At 1000 N, strain amplitude in 0.75 mm cages (481µÎµ) was higher by 39% than that in 1.00 mm cages. These amplitudes corresponded to the mechanobiological range of bone homeostasis+formation, with 63 ± 2% (p < .05 vs other groups), 72 ± 3%, and 73 ± 1% of struts within that range for 1.00 mm at 1000 N, 1.00 mm at 2000 N, and 0.75 mm at 1000 N, respectively. The effective compressive modulus for both cage designs was also dependent on strut diameter, with modulus decreasing from 12.1 ± 2.3 GPa (1.25 mm) to 9.2 ± 7.5 GPa (1.00 mm) and 3.8 ± 0.6 GPa (0.75 mm). This study extended past micro-scale mechanical characterization of trussed cages to compare the effects of design on cage mechanical behavior at moderate (1000 N) and strenuous (2000 N) load levels. The findings suggest that future cage designs may be modulated to target desired mechanical strain regimes at physiological loads.

Clinical experience in cell-based therapeutics: disc chondrocyte transplantation A treatment for degenerated or damaged intervertebral disc.

Disc herniation treated by discectomy results in a significant loss of nucleus material and disc height. Biological restoration through the use of autologous disc chondrocyte transplantation offers a potential to achieve functional integration of disc metabolism and mechanics. Chondrocytes that have been removed from damaged cartilaginous tissues maintain a capacity to proliferate, produce and secrete matrix components and respond to physical stimuli such as dynamic loading. Nucleus regeneration using autologous cultured disc-derived chondrocytes (ADCT) has been demonstrated in a canine model and in clinical pilot studies. In 2002 a prospective, controlled, randomised, multi-center study, EuroDISC, comparing safety and efficacy of autologous disc chondrocyte transplant, chondrotransplant DISC, plus discectomy (ADCT), with discectomy alone was initiated. A dog model was used to investigate the hypothesis that autologous disc chondrocytes can be used to repair damaged intervertebral disc. Disc chondrocytes were harvested and expanded in culture under controlled and defined conditions, returned to the same animals from which they had been sampled (autologous transplantation) via percutaneous delivery. The animals were analyzed at specific times after transplantation by several methods to examine whether disc chondrocytes integrated with the surrounding tissue, produced the appropriate intervertebral disc extracellular matrix, and might provide a formative solution to disc repair. The clinical goals of the EuroDISC study, were to provide long-term pain relief, maintain disc height and prevent adjacent segment disease. Interim analysis was performed after 2 years; Oswestry (low back pain/disability), Quebec Back-Pain Disability Scale, as well as Prolo and VAS score were used for the evaluation. Disc height was assessed by MRI. In the context of degenerative changes in an injury model: () autologous disc chondrocytes were expended in culture and returned to the disc by a minimally invasive procedure after 12 weeks; () disc chondrocytes remained viable after transplantation as shown by bromodeoxyuridine incorporation and maintained a capacity for proliferation after transplantation as depicted by histology; () transplanted disc chondrocytes produced an extracellular matrix that displayed composition similar to normal intervertebral disc tissue. Positive evidence of Proteoglycan content was supported by accepted histochemical staining techniques such as Safranin O-Fast Green; () both Type II and Type I collagens were demonstrated in the regenerated intervertebral disc matrix by immunohistochemistry after chondrocyte transplantation; and () when the disc heights were analyzed for variance according to treatment a statistically significant-correlation between transplanting cells and retention of disc height was achieved. A clinically significant reduction of low back pain in the ADCT-treated group was shown by all three pain score systems. The median total Oswestry score was 2 in the ADCT-treated group compared with 6 in the control group. Decreases in the disability index and VAS score in ADCT-treated patients correlated strongly with the reduction of low back pain. Decreases in disc height over time were only found in the control group, and of potential significance, intervertebral discs in adjacent segments appeared to retain hydration when compared to those adjacent to levels that had undergone discectomy without cell intervention. Autologous chondrocyte transplantation is technically feasible and biologically relevant to repairing disc damage and retarding disc degeneration.

Ex vivo loading of trussed implants for spine fusion induces heterogeneous strains consistent with homeostatic bone mechanobiology.

A truss structure was recently introduced as an interbody fusion cage. As a truss system, some of the connected elements may be in a state of compression and others in tension. This study aimed to quantify both the mean and variance of strut strains in such an implant when loaded in a simulated fusion condition with vertebral body or contoured plastic loading platens ex vivo. Cages were each instrumented with 78 fiducial spheres, loaded between platens (vertebral body or contoured plastic), imaged using high resolution micro-CT, and analyzed for deformation and strain of each of the 221 struts. With repeated loading of a cage by vertebral platens, the distribution (variance, indicated by SD) of strut strains widened from 50N control (4±114µÎµ, mean±SD) to 1000N (-23±273µÎµ) and 2000N (-48±414µÎµ), and between 1000N and 2000N. With similar loading of multiple cages, the strain distribution at 2000N (23±389µÎµ) increased from 50N control. With repeated loading by contoured plastic platens, induced strains at 2000N had a distribution similar to that induced by vertebral platens (84±426µÎµ). In all studies, cages exhibited increases in strut strain amplitude when loaded from 50N to 1000N or 2000N. Correspondingly, at 2000N, 59-64% of struts exhibited strain amplitudes consistent with mechanobiologically-regulated bone homeostasis. At 2000N, vertically-oriented struts exhibited deformation of -2.87±2.04µm and strain of -199±133µÎµ, indicating overall cage compression. Thus, using an ex vivo 3-D experimental biomechanical analysis method, a truss implant can have strains induced by physiological loading that are heterogeneous and of amplitudes consistent with mechanobiological bone homeostasis.

Multiple osteochondroma of the hand: initial and long-term follow-up study.

BACKGROUND: The purpose is to determine the location and type of osteochondromas in patients with multiple osteochondroma of the hand as well as the presence of shortening and angulation. Second, it aims to establish longitudinal data on the change in tumors. METHODS: Retrospective review of patients with multiple osteochondroma affecting the hand evaluating the location and type of tumors as well as the presence of shortening and angulation is done. We examined radiographs from final follow-up and analyzed them based on patient age at presentation (group I = ages 2-6; II = ages 7-10; III = ages 11-19), to determine changes over time and any differences in the number of tumors, location, and shortening and angulation. RESULTS: The most affected bones were the index and small finger metacarpals with an increase seen around the metacarpophalangeal (MCP) joints. The most shortening and angulation were seen on the ulnar side. Group II had the most tumors and the most bones with angulation. Twenty-three hands had longitudinal follow-up with an overall increase of 2.7 tumors per hand with a range of loss of 8 to gain of 16. There was an increase in the number of bones with angulation and shortening. Group I showed the largest increase in tumors, shortening, and angulation. CONCLUSIONS: The ulnar side and bones around the MCP joints are affected most commonly. The largest change was seen as the patients went from young childhood into adolescence, which may be due to rapid growth during this time. This is the largest study of these patients with the longest longitudinal data.

TEM analysis of the nanostructure of normal and osteoporotic human trabecular bone.

Transmission electron microscopy (TEM) was used to investigate the crystal-collagen interactions in normal and osteoporotic human trabecular bone at the nanostructural level. More specifically, two-dimensional TEM observations were used to infer the three-dimensional information on the shape, the size, the orientation, and the alignment of apatite crystals in collagen fibrils in normal and osteoporotic bone. We found that crystals were of platelet shape with irregular edges and that there was no substantial difference in crystal length or crystal thickness between normal and osteoporotic trabecular bone. The crystal arrangement in cross-sectioned fibrils did not neatly conform to the parallel arrangement of crystals seen in longitudinally-sectioned fibrils. Instead, the crystal arrangement in both normal and osteoporotic trabecular bone took on more of a random, undulated arrangement, with certain localized areas demonstrating circular oriented patterns. The TEM imaging was done using bright fields only. Thus, the results presented are within the limitations of this approach.

Nail patella syndrome. A 55-year follow-up of the original description.

The long-term skeletal changes and the lack of significant clinical complaints in a 77-year-old woman with nail patella syndrome are described. Fifty-five years previously she was one of the first reported patients. These early patients came from two families with involvement of multiple individuals with the variable constellation of deformities. We reviewed her skeletal natural history and her family history as it related to nail patella syndrome involvement and treatment, and correlated the original premolecular biology description and subsequent long-term follow-up with the current molecular and genetic concepts of the cause of the variable expression of nail patella syndrome.

Demineralized bone matrix for fracture healing: fact or fiction?

Demineralized bone matrix (DBM) has been touted as an excellent grafting material; however, there are no Level I studies that use DBM alone in humans to back up this claim. DBM functions best in a healthy tissue bed but should be expected to have little impact in an anoxic or avascular tissue bed, a situation often encountered in traumatic orthopaedic pathologies. Moreover, there is some evidence of differential potencies of DBM preparations based on donor variability and the manufacturing process. DBM efficacy may also be related to its formulation and the various carriers used. The fact that DBM is an allogeneic material opens up the potential for disease transmission. In addition, DBM activity may be altered by the hormonal status or nicotine use of a patient. In summary, although DBM has proven effective for bone induction in lower form animals, the translation to human clinical use for fracture healing, and the burden of proof, remains.