Antibiotic-laden bone cement is an important strategy of treatment for an established bone infection. It was aimed to find the safe antibiotic dose intervals of the antibiotic cements soaked in Phosphate Buffered Saline solution and to determine whether there was a difference in terms of
A population based finite element study that accounts for subject-specific morphology, density and load variations, suggests that osteoporosis does not markedly lower the mechanical compliance of the proximal femur to routine loads. Osteoporosis (OP) is a bone disease defined by low bone density and micro-architectural deterioration. This deterioration is neither uniform nor symmetric at the proximal femur. Evidence from analyses performed at the tissue level suggests that the cortical shell at the femoral neck is thinner in OP patients, especially in the superior regions, but not in the infero-anterior ones [Poole, Rubinacci]. Analogously, OP femurs show a higher anisotropy of the trabecular bone than controls [Ciarelli], suggesting a preservation of load bearing capacity in the principal loading direction vs. the transverse one. There is general consensus that the regions subjected to higher loads during walking, which is the predominant motor activity in the elderly, are mostly preserved. All these findings suggest that the OP femur should exhibit an almost normal mechanical competence during daily activities. This would be in accordance with the very low incidence of spontaneous fractures [Parker] and with the moderate fracture predictivity of BMD. Although reasonable, this hypothesis has never been tested at the organ level. Aim of the present study was to verify it with a population-based finite element (FE) study.Summary Statement
Introduction
To address the current challenge of anterior cruciate ligament (ACL) reconstruction, this study is the first to fabricate a braided collagen rope (BCR) which mimics native hamstring for ACL reconstruction. The study aims to evaluate the biological and biomechanical properties of BCR both in vivo and vitro. Rabbit ACL reconstruction model using collagen rope and autograft (hamstring tendon) was conducted. The histological and biomechanical evaluations were conducted at 6-, 12-, 18, 26-week post-operation. In vitro study included cell morphology analysis, cell function evaluation and RNA sequencing of the tenocytes cultured on BCR. A cadaver study was also conducted to verify the feasibility of BCR for ACL reconstruction. BCR displays satisfactory
A spine compression fracture is a very common form of fracture in elderly with osteoporosis. Injection of polymethyl methacrylate (PMMA) to fracture sites is a minimally invasive surgical treatment, but PMMA has considerable clinical risks. We develop a novel type thermoplastic injectable bone substitute contains the proprietary composites of synthetic ceramic bone substitute and absorbable thermoplastic polymer. We used thermoplastic biocompatible polymers Polycaproactone (PCL) to encapsulate calcium-based bone substitutes hydroxyapatite (Ca10(PO4)6(OH)2, HA) and tricalcium phosphate (TCP) to form a biodegradable injectable bone composite material. The space occupation ration PCL:HA/TCP is 1:9. After heating process, it can be injected to fracture site by specific instrument and then self-setting to immediate reinforce the vertebral body. The thermoplastic injection bone substitute can obtain good injection properties after being heated by a heater at 90˚C for three minutes, and has good anti-washout property when injected into normal saline at 37˚C. After three minutes, solidification is achieved. Mechanical properties were assessed using the material compression test system and the mechanical support close to the vertebral spongy bone. In vitro cytotoxicity MTT assay (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) was performed and no cell cytotoxicity was observed. In vivo study with three New Zealand rabbits was performed, well bone growth into bone substitute was observed and can maintain good mechanical support after three months implantation. The novel type thermoplastic injection bone substitute can achieve (a) adequate injectability and viscosity without the risk of cement leakage; (b) adequate
In 2021 the bone grafting market was worth €2.72 billion globally. As allograft bone has a limited supply and risk of disease transmission, the demand for synthetic grafting substitutes (BGS) continues to grow while allograft bone grafts steadily decrease. Synthetic BGS are low in
Residual tumor cells left in the bone defect after malignant bone tumor resection can result in local tumor recurrence and high mortality. Therefore, ideal bone filling materials should not only aid bone reconstruction or regeneration, but also exert local chemotherapeutic efficacy. However, common bone substitutes used in clinics are barely studied in research for local delivery of chemotherapeutic drugs. Here, we aimed to use facile manufacturing methods to render polymethylmethacrylate (PMMA) cement and ceramic granules suitable for local delivery of cisplatin to limit bone tumor recurrence. Porosity was introduced into PMMA cement by adding 1-4% carboxymethylcellulose (CMC) containing cisplatin, and chemotherapeutic activity was rendered to two types of granules via adsorption. Then, mechanical properties, porosity, morphology, drug release kinetics, ex vivo reconstructive properties of porous PMMA and in vitro anti-cancer efficacy against osteosarcoma cells were assessed. Morphologies, molecular structures, drug release profiles and in vitro cytostatic effects of two different drug-loaded granules on the proliferation of metastatic bone tumor cells were investigated. The
We developed a novel silorane-based biomaterial (SBB) for use as an orthopedic cement. SBB is comprised of non-toxic silicon-based monomers, undergoes non-exothermic polymerization, and has weight-bearing strength required of orthopedic cements. We sought to compare the antibiotic release kinetics of this new cement to that of commercially available PMMA bone cement. We also evaluated each material's inherent propensity to support the attachment of bacteria under both static and dynamic conditions. One gram of either rifampin or vancomycin was added to 40g batches of PMMA and SBB. Pellets were individually soaked in PBS. Eluate was collected and tested daily for 14 days using HPLC. Compressive strength and modulus were tested over 21 days. Bioassays were used to confirm the bioactivity of the antibiotics eluted. We measured the growth and maturation of staphylococcus aureus (SA) biofilm on the surface of both PMMA and SBB disks over the course of 72 hours in a static well plate and in a dynamic biofilm reactor (CDC Biofilm Reactor). N=4 at 24, 48, and 72 hours. A luminescent strain of SA (Xen 29) was employed allowing imaging of bacteria on the discs. SBB eluted higher concentrations of vancomycin than did PMMA over the course of 14 days (p<0.001). A significant 55.1% greater day 1 elution was observed from SBB. Silorane cement was able to deliver rifampin in clinically favorable concentrations over 14 days. On the contrary, PMMA was unable to deliver rifampin past day 1. The incorporation of rifampin into PMMA severely reduced its
Varus malalignment increases the susceptibility of cartilage to mechanical overloading, which stimulates catabolic metabolism to break down the extracellular matrix and lead to osteoarthritis (OA). The altered mechanical axis from the hip, knee to ankle leads to knee joint pain and ensuing cartilage wear and deterioration, which impact millions of the aged population. Stabilization of the remaining damaged cartilage, and prevention of further deterioration, could provide immense clinical utility and prolong joint function. Our previous work showed that high tibial osteotomy (HTO) could shift the mechanical stress from an imbalanced status to a neutral alignment. However, the underlying mechanisms of endogenous cartilage stabilization after HTO remain unclear. We hypothesize that cartilage-resident mesenchymal stem cells (MSCs) dampen damaged cartilage injury and promote endogenous repair in a varus malaligned knee. The goal of this study is to further examine whether HTO-mediated off-loading would affect human cartilage-resident MSCs' anabolic and catabolic metabolism. This study was approved by IACUC at Xi'an Jiaotong University. Patients with medial compartment OA (52.75±6.85 yrs, left knee 18, right knee 20) underwent open-wedge HTO by the same surgeons at one single academic sports medicine center. Clinical data was documented by the Epic HIS between the dates of April 2019 and April 2022 and radiographic images were collected with a minimum of 12 months of follow-up. Medial compartment OA with/without medial meniscus injury patients with unilateral Kellgren /Lawrence grade 3–4 was confirmed by X-ray. All incisions of the lower extremity healed well after the HTO operation without incision infection. Joint space width (JSW) was measured by uploading to ImageJ software. The Knee injury and Osteoarthritis Outcome Score (KOOS) toolkit was applied to assess the pain level. Outerbridge scores were obtained from a second-look arthroscopic examination. RNA was extracted to quantify catabolic targets and pro-inflammatory genes (QiaGen). Student's t test for two group comparisons and ANOVA analysis for differences between more than 2 groups were utilized. To understand the role of mechanical loading-induced cartilage repair, we measured the serial changes of joint space width (JSW) after HTO for assessing the state of the cartilage stabilization. Our data showed that HTO increased the JSW, decreased the VAS score and improved the KOOS score significantly. We further scored cartilage lesion severity using the Outerbridge classification under a second-look arthroscopic examination while removing the HTO plate. It showed the cartilage lesion area decreased significantly, the full thickness of cartilage increased and
Current strategy for orthopedic tissue engineering mainly focusses on the regeneration of the damaged tissue using cell-seeded three-dimensional scaffolds. Biocompatible scaffolds with controllable degradation and suitable mechanical property are required to support new tissue in-growth and regeneration . [1]. Porous composite scaffolds made from organic and inorganic materials are highly preferred, which can mimic the natural bone in their composition as well can enhance tissue repair . [2]. Scaffolds with optimum
Objectives. The objective of this study was to determine if combining variations in mixing technique of antibiotic-impregnated polymethylmethacrylate (PMMA) cement with low frequency ultrasound (LFUS) improves antibiotic elution during the initial high phase (Phase I) and subsequent low phase (Phase II) while not diminishing
As compared to magnesium (Mg) and iron (Fe), solid zinc (Zn)-based absorbable implants show better degradation rates. An ideal bone substitute should provide sufficient mechanical support, but pure Zn itself is not strong enough for load-bearing medical applications. Modern processing techniques, like additive manufacturing (AM), can improve
After anterior cruciate ligament (ACL) rupture, reconstructive surgery with a hamstring tendon autograft is often performed. Despite overall good results, ACL re-rupture occurs in up to 10% of the patient population, increasing to 30% of the cases for patients aged under 20 years. This can be related to tissue remodelling in the first months to years after surgery, which compromises the graft's
Treatment of tendon and ligament injuries remains challenging; the aim is to find a biocompatible substance with mechanical and structural properties that replicate those of normal tendon and ligament. We examined the mechanical properties of Demineralised Cortical Bone (DCB) after gamma irradiation (GI) and freeze drying (FD). We also used different techniques for repairing bone-tendon-bone with DCB in order to measure the mechanical performance of the construct. DCB specimens were allocated into 4 groups; FD, GI, combination of both or none. The maximum tensile forces and stresses were measured. 4 cadaveric models of repair of 1cm patellar tendon defect using DCB were designed; model-1 using one bone anchor, Model-2 using 2 bone anchors, Model-3 off-loading by continuous thread looped twice through bony tunnels, Model-4 off-loading with 3 hand braided threads. Force to failure and mode were recorded for each sample. FD groups results were statistically higher (p=<0.05) compared to non-FD groups, while there was no statistical difference between GI and non-GI groups. The median failure force for model-1: 250N, model-2: 290N, model-3: 767N and model-4: 934N. There was no statistical significance between model-1 and model-2 (p=0.249), however statistical significance was found between other models (p=<0.006). GI has no significant effect on
Background. External fixation is a method of osteosynthesis currently required in traumatology and orthopaedic surgery. Pin tract infection is a common problem in clinical practice. Infection occurs after a bacterial colonisation of the pin due to its contact with skin and local environment. To prevent such local contamination, one way to handle this issue is to create a specific coating using method which could be applied in the medical field. In this work we develop a surface coating for external fixator pins based on photocatalytic TiOα properties, producing a bactericidal effect with sufficient
Summary Statement. We evaluated the
Objectives. Bisphosphonates (BP) are the first-line treatment for preventing fragility fractures. However, concern regarding their efficacy is growing because bisphosphonate is associated with over-suppression of remodelling and accumulation of microcracks. While dual-energy X-ray absorptiometry (DXA) scanning may show a gain in bone density, the impact of this class of drug on mechanical properties remains unclear. We therefore sought to quantify the
Summary Statement. This study describes the design and preliminary in vitro testing of a novel patch for the repair of rotator cuff tendon tears. The laminated design incorporates woven and electrospun components. The woven element provides the patch with excellent
Biometals like Magnesium (Mg) and Zinc (Zn) are essential for life. Mg/Zn-deficiency has been linked to numerous diseases including cardiovascular, bone, diabetics, neurological and neurodegenerative disorders. Moreover, Mg/Zn-based biomaterials have recently emerged as innovative degradable medical implants, typically for cardiovascular and orthopedic application. We study the pathophysiological role of Mg. 2+. /Zn. 2+. ion in vascular and bone diseases, as well as metallic Mg/Zn alloys for stent and bone implant applications. We demonstrated some interesting role and mechanism of Mg. 2+. /Zn. 2+. ion in controlling cellular functions. Also, metallic Mg/Zn-based medical implants exhibited strong potential as stent and bone fixation device. They have sufficient
In order to evaluate the feasibility of zinc alloys as future biodegradable bone implant materials, the mechanical properties, corrosion resistance, hemocompatibility, cell activity, proliferation and adhesion, in vivo animal implantation experiments have been employed. The experimental results show that the alloying element magnesium, calcium and strontium can significantly improve the mechanical properties of pure zinc, and further deformation processes can further improve the mechanical properties of zinc alloys. Alloying elements can effectively control the corrosion rates of zinc alloys, which are between the rates of magnesium alloys and iron alloys. Zinc and zinc alloys exhibit excellent hemocompatibility and the hemolysis rate is far lower than 5%. After adding alloying elements Mg, Ca and Sr, MG63 and ECV304 cell proliferation rate and activity increased significantly, while for VSMC cell, the influence of alloying elements effect is not obvious. Zinc alloy intramedullary pins can effectively promote the new bone formation, and after 2 months implanted in mice femur, they still maintained a relatively complete structure, indicating that they are able to provide enough
Biomechanical analysis is important to evaluate the effect of orthopaedic surgeries. CT-image based finite element method (CT-FEM) is one of the most important techniques in the computational biomechanics field. We have been applied CT-FEM to evaluate resorptive bone remodeling, secondary to stress shielding, after total hip arthroplasty (THA). We compared the equivalent stress and strain energy density to postoperative BMD (bone mineral density) change in the femur after THA, and a significant correlation was observed between the rate of changes in BMD after THA and equivalent stress. For periacetabular osteotomy cases, we investigated mechanical stress in the hip joint before and after surgery. Mechanical stress in the hip joint decreased significantly after osteotomy and correlated with the degree of the acetabular coverage. For arthroscopic osteochondroplasty cases, we examined