Aims. To investigate metallosis in patients with magnetically controlled growing rods (MCGRs) and characterize the metal particle profile of the tissues surrounding the rod. Methods. This was a prospective observational study of patients with early onset scoliosis (EOS) treated with MCGRs and undergoing rod exchange who were consecutively recruited between February 2019 and January 2020. Ten patients were recruited (mean age 12 years (SD 1.3); 2 M:8 F). The configurations of the MCGR were studied to reveal the distraction mechanisms, with crucial rod parts being the distractable piston rod and the magnetically driven rotor inside the barrel of the MCGR. Metal-on-metal contact in the form of ring-like wear marks on the piston was found on the distracted portion of the piston immediately outside the barrel opening (BO) through which the piston rod distracts. Biopsies of paraspinal muscles and control tissue samples were taken over and away from the wear marks, respectively. Spectral analyses of the rod alloy and biopsies were performed to reveal the metal constituents and concentrations.
Introduction and Objective. Heterotopic ossification is the formation of extraskeletal mineralized tissue commonly associated with either trauma or surgery. While several mouse models have been developed to better characterize the pathologic progression of HO, no model currently exists to study HO of the hip, the most common location of acquired HO in patients. Owing to the unique biological mechanisms underpinning the formation of HO in different tissues, we sought to develop a model to study the post-surgical HO of the hip. Materials and Methods. Wild-type mice C57BL/6J mice were used to study the procedure outcomes, while Pdgfra-CreERT2;mT/mG and Scx-GFP reporter animals were used for the lineage tracing experiments (total n=16 animals, male, 12 weeks old). An anterolateral approach to the hip was performed. Briefly, a 2 cm incision was made centered on the great trochanter and directed proximal to the iliac crest and distally over the lateral shaft of the femur. The joint was then reached following the intermuscular plane between the rectus femoris and gluteus medius muscles. After the joint was exposed, the articular cartilage was removed using a micropower drill with a 1.2 mm reamer. The medius gluteus and superficial fascia were then re-approximated with Vicryl 5-0 suture (Ethicon Inc, Somerville, NJ) and skin was then closed with Ethilon 5-0 suture (Ethicon Inc). Live high resolution XR imaging was performed every 2 wks to assess the skeletal tissues (Faxitron Bioptics, Tucson, AZ). The images were then scored using the Brooker classification. Ex-vivo microCT was conducted using a Skyscan 1275 scanner (Bruker-MicroCT, Kontich, Belgium). 3D reconstruction and analysis was performed using Dragonfly (ORS Inc., Montreal, Canada). For the histological analysis of specimens, Hematoxylin and Eosin (H&E), modified Goldner's Trichrome (GMT) stainings were performed. Reporter activity was assessed using fluorescent imaging. Results. Substantial periarticular heterotopic bone was seen in all cases. A periosteal reaction and an initial formation of calcified tissue within the soft tissue was apparent starting from 4 wks after surgery. By XR, progressive bone formation was observed within the periosteum and intermuscular planes during the subsequent 8 weeks. Stage 1 HO was observed in 12.5% of cases, stage 2 in 62.5% of cases, and stage 3 HO in 25% of cases. 3D microCT reconstructions of the treated hip joints demonstrated significant de novo heterotopic bone in several location which phenocopy human disease. Heterotopic bone was observed in an intracapsular location, periosteal location involving the iliac bone and proximal femur, and intermuscular locations.
Osteoarthritis (OA) is a disease that affects both bone and cartilage. Typically, this disease leads to cartilage degradation and subchondral bone sclerosis but the link between the two is unknown. Also, while OA was traditionally thought of as non-inflammatory condition, it now seems that low levels of inflammation may be involved in the link between these responses. This is particularly relevant in the case of Post-Traumatic OA (PTOA), where an initial phase of synovial inflammation occurs after injury. The inflammatory mediator interleukin 1 beta (IL-1B) is central to this response and contributes to cartilage degradation. However, whether there is a secondary effect of this mediator on subchondral bone, via bone-cartilage crosstalk, is not known. To address this question, we developed a novel patellar explant model, to study bone cartilage crosstalk which may be more suitable than commonly used femoral head explants. The specific aim of this study was to validate this novel patellar explant model by using IL-1B to stimulate the inflammatory response after joint injury and the subsequent development of PTOA. Female Sprague Dawley rats (n=48) were used to obtain patellar explants, under an institutional ethical approval license. Patellae were maintained in high glucose media, under sterile culture conditions, with or without IL-1B (10ng/ml), for 7 days. Contralateral patellae served as controls. One group (n= 12) of patellae were assessed for active metabolism, using two both Live and Dead (L/D) staining and an Alamar Blue assay (AB). A second group (n=12) was used for tissue specific biochemical assays for both bone (Alkaline Phosphatase) and cartilage (sulfated proteoglycan and glycosaminoglycan (sGaG)). Finally, a third group (n=28) of explants were used for histologically analysis. Samples were decalcified, embedded in paraffin and sectioned to 7µm thickness, and then stained using H&E; and Safranin O with fast green. Additionally, toluidine blue and alkaline phosphatase staining were also performed. Our results demonstrate that our system can maintain good explant viability for at least 7 days, but that IL-1B reduces cell viability in patellar cartilage, as measured by both L/D and AB assays after 0, 2, 4 and 7 days in culture. In contrast, sGaG content in cartilage were increased by this treatment. Additionally, ALP, a marker of osteoblastic activity, was increased in IL-1B treated group 4 and 7 days, but was also showed some increase in control groups.
Tenomodulin (Tnmd) is the best known mature tendon factor for tendon and ligament tissues with reported important regulatory roles1. In addition, Tnmd C-terminal cysteine-rich domain has been descibed to exert anti-angiogenic functions in in vitro angiogenic assays as well as in vivo models of tendon injury and age-associated cardiac valve diseases1, 2. Interestingly, Tnmd expresson in the intervertebral disc (IVD), which is normally avascular tissue, has been also suggested3. Hence, the purpose of this study was first, to map the exact expression pattern of Tnmd during IVD development and aging and second, by implementing Tnmd-knockout mouse model, to examine if Tnmd plays a role in IVD homeostasis.
Mesenchymal Stromal Cells (MSC) are promising therapies for fracture healing. However, undifferentiated MSC may act only through an inductive paracrine effect without direct bone formation. Here, we developed an injectable product constituted of human bone-forming cells derived from bone marrow (BM)-MSC (ALLO-P2) that display more potent bone repair properties not only by stimulating host osteoinduction but also by direct bone formation. In vitro, ALLO-P2 overexpressed markers such as ALP compared to BM-MSC isolated from the same donors, suggesting their engagement into the osteogenic lineage. In vivo, a single dose of ALLO-P2 significantly enhanced bone neoformation 14 days post-administration over the calvaria of NMRI-Nude mice compared to the control excipient.
Skeletal sequels of traumatisms, diseases or surgery often lead to bone defects that fail to self-repair. Although the gold standard for bone reconstruction remains the autologous bone graft (ABG), it however exhibits some drawbacks and bone substitutes developed to replace ABG are still far for having its bone regeneration capacity. Herein, we aim to assess a new injectable allogeneic bone substitute (AlloBS) for bone reconstruction. Decellularized and viro-inactivated human femoral heads were crushed then sifted to obtain cortico-spongious powders (CSP). CSP were then partly demineralized and heated, resulting in AlloBS composed of particles consisting in a mineralized core surrounded by demineralized bone matrix, engulfed in a collagen I gelatin. Calvarial defects (5mm in diameter, n=6/condition) in syngeneic Lewis1A rats were filled with CSP, AlloBS±TBM (total bone marrow), BCP (biphasic calcium phosphate)±TBM or left unfilled (control). After 7 weeks, the mineral volume/total volume (MV/TV) ratios were measured by µCT and Movat's pentachrome staining were performed on undemineralized frontal sections. The MV/TV ratios in defects filled with CSP, AlloBS or BCP were equivalent, whereas the MV/TV ratio was higher in AlloBS+TBM compared to CSP, AlloBS or BCP (p<0.01; Mann-Whitney).
Background. Administration of Botulinum toxin type A (BTX-A) in patients with spastic cerebral palsy aims to improve mobility by increasing joint range of motion and decreasing passive resistance. However, our recent animal experiments indicated that BTX-A can decrease muscle”s length range of force exertion (Lrange), and increase its passive forces and extracellular matrix (ECM) collagen content. Moreover, BTX-A injected into the tibialis anterior (TA) was shown to spread into non-injected synergistic muscles in the whole anterior crural compartment. These effects that contradict the treatment aims deserve further investigation. Aim. To test in a rat model if: (1) BTX-A injected into the medial and lateral gastrocnemius (GM&GL) muscles spreads into the synergistic soleus (SOL) as well as antagonistic TA and extensor digitorum longus (EDL). (2) The muscles exposed show a wider Lrange, decreased muscle passive force and reduced ECM collagen. Methods. 2×0.1U/20µl of BTX-A (BTX-A group, n=6) or only 2×20µl of saline (Control group, n=6) were prepared and each was injected into the mid-belly of the GM and GL separately. 5 days post injection, forces of all muscles were measured in passive state and also on activation. The GM&GL length was changed whereas; all other muscles were kept at constant length. After biomechanical testing, the muscles were histologically analyzed using Gomori trichrome stain to detect ECM collagen. Two-way ANOVA (factors: GM&GL length and animal group) was used to assess BTX-A effects on forces, and the Kruskal-Wallis test was used to test the change in proportion of collagenous tissue for each muscle. Differences were considered significant at p<0.05. Results. Injected muscles: ANOVA showed significant main effects of both factors on GM&GL total forces and a significant interaction. Force reductions are more pronounced at shorter lengths (increase from 80.8% to 88.4% with decreasing length). Lrange decreased (by 24.1%). ANOVA showed significant main effects of only muscle length on GM&GL passive forces and no significant interaction. Non-injected muscles: ANOVA showed significant main effects of both factors (for SOL), or only of BTX-A (for TA and EDL) only on muscle total forces, but no significant interaction. Force drops for the SOL (89.8%) and anterior crural muscles (57.0% and 51.0% for TA and EDL) do indicate spread of BTX-A intra- and extra-compartmentally.
Summary. A novel in vivo animal model to establish new surgical interventions for patients with ACL insufficiency. Introduction. After ACL reconstruction, recruited cells from surrounding tissues play crucial roles in ligamentization to obtain adequate structural properties. To allow athletes to return sports activity sooner, these remodeling processes should be elucidated and be accelerated. However, in conventional animal models, it has been difficult to differentiate donor and recipient cells. Here we introduce the transgenic Kusabira-Orange pigs, in which cells produce fluorescence systemically, as in vivo model to trace cell recruitment after ACL reconstruction. Methods. After the approval by the Institutional Animal Care and Used Committee, a transgenic pig that carries and produces red fluorescent Kusabira-Orange (KO) was established. Skeletally immature transgenic pigs (n=12) (20 wks old, 76.0 ± 17.5 kg) and wild type (WT) pigs were used as recipient and donor, respectively. For validation of the pigs as in vivo model, the ACL histological structure, cell shape, mitogenic activity, and migration activity were assessed and were compared to those of wild type pigs. The sensitivity and specificity of KO fluorescence under microscopy were
The optimum type of antibiotics and their administration route for treating Gram-negative (GN) periprosthetic joint infection (PJI) remain controversial. This study aimed to determine the GN bacterial species and antibacterial resistance rates related to clinical GN-PJI, and to determine the efficacy and safety of intra-articular (IA) antibiotic injection after one-stage revision in a GN pathogen-induced PJI rat model of total knee arthroplasty. A total of 36 consecutive PJI patients who had been infected with GN bacteria between February 2015 and December 2021 were retrospectively recruited in order to analyze the GN bacterial species involvement and antibacterial resistance rates. Antibiotic susceptibility assays of the GN bacterial species were performed to screen for the most sensitive antibiotic, which was then used to treat the most common GN pathogen-induced PJI rat model. The rats were randomized either to a PJI control group or to three meropenem groups (intraperitoneal (IP), IA, and IP + IA groups). After two weeks of treatment, infection control level, the side effects, and the volume of antibiotic use were evaluated.Aims
Methods
Cartilage injuries rarely heal spontaneously and often require surgical intervention, leading to the formation of biomechanically inferior fibrous tissue. This study aimed to evaluate the possible effect of amelogenin on the healing process of a large osteochondral injury (OCI) in a rat model. A reproducible large OCI was created in the right leg femoral trochlea of 93 rats. The OCIs were treated with 0.1, 0.5, 1.0, 2.5, or 5.0 μg/μl recombinant human amelogenin protein (rHAM+) dissolved in propylene glycol alginate (PGA) carrier, or with PGA carrier alone. The degree of healing was evaluated 12 weeks after treatment by morphometric analysis and histological evaluation. Cell recruitment to the site of injury as well as the origin of the migrating cells were assessed four days after treatment with 0.5 μg/μl rHAM+ using immunohistochemistry and immunofluorescence.Aims
Methods
Pigment epithelium-derived factor (PEDF) is known to induce several types of tissue regeneration by activating tissue-specific stem cells. Here, we investigated the therapeutic potential of PEDF 29-mer peptide in the damaged articular cartilage (AC) in rat osteoarthritis (OA). Mesenchymal stem/stromal cells (MSCs) were isolated from rat bone marrow (BM) and used to evaluate the impact of 29-mer on chondrogenic differentiation of BM-MSCs in culture. Knee OA was induced in rats by a single intra-articular injection of monosodium iodoacetate (MIA) in the right knees (set to day 0). The 29-mer dissolved in 5% hyaluronic acid (HA) was intra-articularly injected into right knees at day 8 and 12 after MIA injection. Subsequently, the therapeutic effect of the 29-mer/HA on OA was evaluated by the Osteoarthritis Research Society International (OARSI) histopathological scoring system and changes in hind paw weight distribution, respectively. The regeneration of chondrocytes in damaged AC was detected by dual-immunostaining of 5-bromo-2'-deoxyuridine (BrdU) and chondrogenic markers.Aims
Methods
Several artificial bone grafts have been developed but fail to achieve anticipated osteogenesis due to their insufficient neovascularization capacity and periosteum support. This study aimed to develop a vascularized bone-periosteum construct (VBPC) to provide better angiogenesis and osteogenesis for bone regeneration. A total of 24 male New Zealand white rabbits were divided into four groups according to the experimental materials. Allogenic adipose-derived mesenchymal stem cells (AMSCs) were cultured and seeded evenly in the collagen/chitosan sheet to form cell sheet as periosteum. Simultaneously, allogenic AMSCs were seeded onto alginate beads and were cultured to differentiate to endothelial-like cells to form vascularized bone construct (VBC). The cell sheet was wrapped onto VBC to create a vascularized bone-periosteum construct (VBPC). Four different experimental materials – acellular construct, VBC, non-vascularized bone-periosteum construct, and VBPC – were then implanted in bilateral L4-L5 intertransverse space. At 12 weeks post-surgery, the bone-forming capacities were determined by CT, biomechanical testing, histology, and immunohistochemistry staining analyses.Aims
Methods
To verify whether secretory leucocyte protease inhibitor (SLPI) can promote early tendon-to-bone healing after anterior cruciate ligament (ACL) reconstruction. In vitro: the mobility of the rat bone mesenchymal stem cells (BMSCs) treated with SLPI was evaluated by scratch assay. Then the expression levels of osteogenic differentiation-related genes were analyzed by real-time quantitative PCR (qPCR) to determine the osteogenic effect of SLPI on BMSCs. In vivo: a rat model of ACL reconstruction was used to verify the effect of SLPI on tendon-to-bone healing. All the animals of the SLPI group and the negative control (NC) group were euthanized for histological evaluation, micro-CT scanning, and biomechanical testing.Aims
Methods
Titanium is a popular orthopaedic implant material, but it requires surface modification techniques to improve osseointegration and long term functionality. This project compares a new method of modifying surface topography (nano-patterning) with an existing clinical technology (grit-blasting and acid-etching (GAE)). Titanium discs were blasted with aluminium oxide and etched in sulphuric and acetic acid. Injection moulded discs (with two different nano-patterns) were coated in titanium by evaporation. The topography and chemistry of the discs was assessed using atomic force microscopy (AFM), scanning electron microscopy (SEM), water contact angle measurements, and X-ray photo-electron spectroscopy (XPS). Two discs were plated bilaterally onto a flattened area of the tibiae of 12 rabbits. Tibiae were removed after 4 and 8 weeks for histological assessment of the bone-implant contact (BIC) ratio. AFM and SEM demonstrated a difference in pattern between the square array of nano-pits (SQ) and the randomly positioned nano-pits (RAND). The GAE implants exhibited increased surface roughness (Ra = 570nm) compared to the titanium coated SQ and RAND implants (Ra = 12nm). Water contact angle measurements showed the surface had comparable wettability and XPS demonstrated similar chemical compositions, except GAE surfaces contained 6.8% aluminium.
Rotator cuff (RC) tears are common musculoskeletal injuries which often require surgical intervention. Noninvasive pulsed electromagnetic field (PEMF) devices have been approved for treatment of long-bone fracture nonunions and as an adjunct to lumbar and cervical spine fusion surgery. This study aimed to assess the effect of continuous PEMF on postoperative RC healing in a rat RC repair model. A total of 30 Wistar rats underwent acute bilateral supraspinatus tear and repair. A miniaturized electromagnetic device (MED) was implanted at the right shoulder and generated focused PEMF therapy. The animals’ left shoulders served as controls. Biomechanical, histological, and bone properties were assessed at three and six weeks.Aims
Methods
In the 1990s, a bioactive bone cement (BABC) containing apatite-wollastonite glass-ceramic (AW-GC) powder and bisphenol-a-glycidyl methacrylate resin was developed at our hospital. In 1996, we used BABC to fix the acetabular component in primary total hip arthroplasty (THA) in 20 patients as part of a clinical trial. The purpose of this study was to investigate the long-term results of primary THA using BABC. A total of 20 patients (three men and 17 women) with a mean age of 57.4 years (40 to 71), a mean body weight of 52.3 kg (39 to 64), and a mean body mass index (BMI) of 23.0 kg/m2 (19.8 to 28.6) were evaluated clinically and radiologically. Survival analyses were undertaken, and wear analyses were carried out using a computer-aided method.Aims
Patients and Methods
As one of the heat-stable enterotoxins, Rat MSCs were used to test the effects of SEC2 on their proliferation and osteogenic differentiation potentials. A rat femoral fracture model was used to examine the effect of local administration of SEC2 on fracture healing using radiographic analyses, micro-CT analyses, biomechanical testing, and histological analyses.Objectives
Materials and Methods
Long bone defects often require surgical intervention for functional restoration. The ‘gold standard’ treatment is autologous bone graft (ABG), usually from the patient’s iliac crest. However, autograft is plagued by complications including limited supply, donor site morbidity, and the need for an additional surgery. Thus, alternative therapies are being actively investigated. Autologous bone marrow (BM) is considered as a candidate due to the presence of both endogenous reparative cells and growth factors. We aimed to compare the therapeutic potentials of autologous bone marrow aspirate (BMA) and ABG, which has not previously been done. We compared the efficacy of coagulated autologous BMA and ABG for the repair of ulnar defects in New Zealand White rabbits. Segmental defects (14 mm) were filled with autologous clotted BM or morcellized autograft, and healing was assessed four and 12 weeks postoperatively. Harvested ulnas were subjected to radiological, micro-CT, histological, and mechanical analyses.Objectives
Methods
We undertook a randomised controlled trial to
compare bipolar hemiarthroplasty (HA) with a novel total hip replacement
(THR) comprising a polycarbonate–urethane (PCU) acetabular component
coupled with a large-diameter metal femoral head for the treatment
of displaced fractures of the femoral neck in elderly patients. Functional
outcome, assessed with the Harris hip score (HHS) at three months
and then annually after surgery, was the primary endpoint. Rates
of revision and complication were secondary endpoints. Based on a power analysis, 96 consecutive patients aged >
70
years were randomised to receive either HA (49) or a PCU-THR (47).
The mean follow-up was 30.1 months (23 to 50) and 28.6 months (22
to 52) for the HA and the PCU group, respectively. The HHS showed no statistically significant difference between
the groups at every follow-up. Higher pain was recorded in the PCU
group at one and two years’ follow-up
(p = 0.006 and p = 0.019, respectively). In the HA group no revision
was performed. In the PCU-THR group six patients underwent revision
and one patient is currently awaiting
re-operation. The three-year survival rate of the PCU-THR group
was 0.841 (95% confidence interval 0.680 to 0.926). Based on our findings we do not recommend the use of the PCU
acetabular component as part of the treatment of patients with fractures
of the femoral neck. Cite this article:
We present an update of the clinical and radiological results of 62 consecutive acetabular revisions using impacted morsellised cancellous bone grafts and a cemented acetabular component in 58 patients, at a mean follow-up of 22.2 years (20 to 25). The Kaplan-Meier survivorship for the acetabular component with revision for any reason as the endpoint was 75% at 20 years (95% confidence interval (CI) 62 to 88) when 16 hips were at risk. Excluding two revisions for septic loosening at three and six years, the survivorship at 20 years was 79% (95% CI 67 to 93). With further exclusions of one revision of a well-fixed acetabular component after 12 years during a femoral revision and two after 17 years for wear of the acetabular component, the survivorship for aseptic loosening was 87% at 20 years (95% CI 76 to 97). At the final review 14 of the 16 surviving hips had radiographs available. There was one additional case of radiological loosening and four acetabular reconstructions showed progressive radiolucent lines in one or two zones. Acetabular revision using impacted large morsellised bone chips (0.5 cm to 1 cm in diameter) and a cemented acetabular component remains a reliable technique for reconstruction, even when assessed at more than 20 years after surgery.