Aims

This study aimed to establish the optimal fixation methods for calcaneal tuberosity avulsion fractures with different fragment thicknesses in a porcine model.

Aims

Pellino1 (Peli1) has been reported to regulate various inflammatory diseases. This study aims to explore the role of Peli1 in the occurrence and development of osteoarthritis (OA), so as to find new targets for the treatment of OA.

Aims

Osteoarthritis (OA) is a common degenerative joint disease characterized by chronic inflammatory articular cartilage degradation. Long noncoding RNAs (lncRNAs) have been previously indicated to play an important role in inflammation-related diseases. Herein, the current study set out to explore the involvement of lncRNA H19 in OA.

Abstract

Abstract

Bone is a connective tissue that undergoes constant remodeling. Any disturbances during this process may result in undesired pathological conditions. A single nucleotide substitution (596T-A) in exon eight which leads to a M199K mutation in human RANKL was found to cause osteoclast-poor autosomal recessive osteopetrosis (ARO). Patients with ARO cannot be cured by hematopoietic stem cell transplantation and, without proper treatments, will die in their early age. To date, how this mutation alters RANKL function has not been characterized. We thus hypothesized that hRANKL M199 residue is a structural determinant for normal RANKL-RANK interaction and osteoclast differentiation. By sharing our findings, we aim to achieve an improved clinical outcome in treating bone-related diseases such as osteoporosis, ARO and osteoarthritis.

Site-directed mutagenesis was employed to create three rat RANKL mutants, replacing the methionine 200 (human M199 equivalent residue) with either lysine (M200K), alanine (M200A) or glutamic acid (M200E). Recombinant proteins were subsequently purified through affinity chromatography and visualized by Coomassie blue staining and western blot. MTS was carried out before osteoclastogenesis assay in vitro to measure the cellular toxicity. Bone resorption pit assay, immuno-fluorescent staining, luciferase reporter assay, RT-PCR, western blot and calcium oscillation detection were also conducted to explore the biological effect of rRANKL mutants. Computational modeling, thermal Shift Assay, western blot and protein binding affinity experiments were later carried out for structural analyses.

rRANKL mutants M200K/A/E showed a drastically reduced ability to induce osteoclast formation and did not demonstrate features of competitive inhibition against wild-type rRANKL. These mutants are all incapable of supporting osteoclastic polarization and bone resorption or activating RANKL-induced osteoclast marker gene transcription. Consistently, they were unable to induce calcium flux, and also showed a diminished induction of IκBa degradation and activation of NF-kB and NFATc1 transcriptional activity. Furthermore, the transcriptional activation of the antioxidant response element (ARE) crucial in modulating oxidative stress and providing cytoprotection was also unresponsive to stimulation with rM200s. Structural analyses showed that rM200 is located in a hydrophobic pocket critical for protein folding. Thermal shift and western blot assays suggested that rM200 mutants formed unstructured proteins, with disturbed trimerisation and the loss of affinity to its intrinsic receptors RANK and OPG.

Taken together, we first demonstrates the underlying cause of M199-meidated ARO in a cellular and molecular level by establishing a phenotype in BMMs similar to observed in human samples. Further investigation hints the structural significance of a hydrophobic pocket within the TNF-like region. Combined with pharmaceutical studies on small-molecule drugs, this finding may represent a therapeutic target motif for future development of anti-resorptive treatments.

Aims

The purpose of this study was to validate our hypothesis that centrifugation may eliminate false-positive leucocyte esterase (LE) strip test results caused by autoimmune diseases in the diagnosis of knee infection.

Objectives

MicroRNAs (miRNAs) have been reported as key regulators of bone formation, signalling, and repair. Fracture healing is a proliferative physiological process where the body facilitates the repair of a bone fracture. The aim of our study was to explore the effects of microRNA-186 (miR-186) on fracture healing through the bone morphogenetic protein (BMP) signalling pathway by binding to Smad family member 6 (SMAD6) in a mouse model of femoral fracture.

All types of regenerative materials, including metal implants, porous scaffolds and cell-laden hydrogels, interact with the living tissue and cells. Such interaction is key to the settlement and regenerative outcomes of the biomaterials. Notably, the immune reactions from the host body crucially mediate the tissue-biomaterials interactions. Macrophages (as well as monocytes and neutrophils), traditionally best known as defenders, accumulate at the tissue-biomaterials interface and secrete abundant cytokines to create a microenvironment that benefits or inhibits regeneration. Because the phenotype of these cells is highly plastic in response to varying stimuli, it may be feasible to manipulate their activity at the interface and harness their power to mediate bone regeneration. Towards this goal, our team have been working on macrophage-driven bone regeneration in two aspects. First, targeting the abundant, glucan/mannan-recognising receptors on macrophages, we have devised a series of glucomannan polymers that can stimulate macrophages to secrete pro-osteogenic cytokines, and applied them as coating polymer of mesenchymal stem cells-laden hydrogels. Second, targeting the toll-like receptors (TLRs) on macrophages, we have screened TLR-activating polysaccharides and picked up zymosan (beta-glucan) to be modified onto titanium and glass implants. We evaluated both the efficacy of integration and safety of immune stimulation in both in vitro and in vivo models. Our future exploration lies in further elaborating the different roles and mechanisms of macrophages of various types and origins in the regenerative process.

Introduction

Blood loss after TKA varied, but not uncommon with up to 1500 ml or a decrease in hemoglobin of 3–4 g/dL. In addition to improving prosthetic alignment, computer-assisted TKAs also contribute to reduced operative blood loss and systemic emboli. These observations imply that navigation TKAs may cause less microvascular endothelial damage than conventional TKAs. Cell adhesion molecules (CAMs) have been employed as markers for endothelial or vascular damage. We hypothesized serum levels of CAMs in patients receiving navigation TKAs may be different from those receiving conventional TKAs.

Introduction

The usefulness of markers of non-specific low back pain (NSLBP), including MRI derived measurements of cross-sectional area (CSA) and functional CSA (FCSA, fat free muscle area) of the lumbar musculature, is in doubt. To our knowledge, such markers remain unexplored in Lumbar Disc Degeneration (LDD), which is significantly associated with NSLBP, Modic change and symptom recurrence. This exploratory 3.0-T MRI study addresses this shortfall by comparing asymmetry and composition in asymptomatic older adults with and without Modic change.

D-dimer is one of the useful laboratory tests to evaluate the incidence of venous thromboembolism (VTE) after the total knee arthroplasty (TKA). The most recent guideline for the prophylaxis of VTE points out the surgical procedure itself is a major risk factor for developing VTE.

Only a few literatures discuss the relationship of surgical procedures and the risk of venous thromboembolism. We therefore prospectively compare the difference of the perioperative plasma D-dimer levels between the patients undergoing navigation and convention TKA.

Two hundred consecutive total knee arthroplasties were performed between September 2011 and March 2013. The patients were randomised according to their registration to the orthopaedic clinic. Ninety-six patients (100 knees) underwent a navigation-assisted TKA and ninety-four patients (100 knees) had a conventional TKA. No intramedullary violation was done in the navigation-assisted TKA, while the intramedullary femoral guiding was adapted in the conventional group.

Pre-operative and post-operation day 1 plasma D-dimer levels were recorded and evaluated using Mann-Whitney U test. There was no difference in the demographic data and pre-operative D-dimer between the two groups (p=0.443). Significantly lower D-dimer levels on the post-operative day 1 were noted in the navigation group, when compared with the conventional group. (6.0 ± 4.4 mg/L vs 11.3 ± 9.6 mg/L, p = 0.000).

We demonstrated that lower D-dimer level is developed after the navigation-assisted TKA than the conventional one. Less incidence of VTE is expected and the finding may help to explain the fact that less systemic emboli in the navigation assisted TKA.

Objective

The objective of this study was to evaluate the rotation and translation of each joint in the hindfoot and compare the load response in healthy feet with that in stage II posterior tibial tendon dysfunction (PTTD) flatfoot by analysing the reconstructive three-dimensional (3D) computed tomography (CT) image data during simulated weight-bearing.

Background:

Full thickness cartilage defect of the knee frequently resulted in fibrous tissue formation, and larger lesions often lead to degenerative arthritis of the knee. Many techniques are designed to repair the cartilage defect including chondrocyte transplantation, microfracture and osteochondral graft. Each method has achieved some success but no universal results. Autologus osteochondral graft has gained in clinical popularity because of its technical feasibility and cost effectiveness.

Background:

Massive rotator cuff tear can cause functional disability due to instability and degenerative changes of the shoulder joint. In patients with massive irreparable rotator cuff tear, tendon transfer is often used as the salvage procedure. Latissimus dorsi and pectoris major transfer are technically demanding procedures and may incur complications. The biceps tendon transfer may provide a biologically superior tissue patch that improves the biomechanics of the shoulder joint in patients with irreparable rotator cuff tear. This study evaluated the functional outcomes of biceps tendon transfer for irreparable rotator cuff tear in 6 patients with two years and longer follow-up.

This study compared the functional outcomes of total hip arthroplasty (THA) in one hip and extracorporeal shockwave (ESWT) in the other hip in patients with bilateral hip necrosis.

Seventeen patients with bilateral hip necrosis were treated with THA for late stage ONFH in one hip and ESWT for early lesion in the other hip. In THA, only one type of prosthesis was used and all components were cementless. In EWST, each hip received 6000 shocks at 28 Kv (equivalent to 0.62 mJ/mm² energy flux density) in a single session. The evaluations included pain score, Harris hip score, radiographs and MR images at 6 and 12 months and then yearly.

Significant improvements in pain score and Harris hip score were noted after treatment in both hips. However, the magnitudes of improvement showed significant differences between the two sides favoring the ESWT side. On subjective assessment, 13 patients rated ESWT better than THA; 4 patients reported comparable results of THA and ESWT, and none graded THA better than ESWT. In THA side, abnormal radiographs were noted in 47% (8 of 17) including component mal-position, nonprogressive radiolucency, and suspected component loosening. In ESWT side, significant reduction of bone marrow edema and a trend of decrease in the size of the lesion were observed after treatment.

ESWT and THA are effective for early and late stages of ONFH respectively.

However, better functional outcomes were observed in ESWT-treated hips than hips treated with THA in patients with bilateral hip disease in short-term.

The effect of shockwave in osteonecrosis of the femoral head (ONFH) is poorly understood. The purpose of this study was to investigate the regeneration effects of shockwave in ONFH.

This study consisted of 14 femoral heads from 14 patients undergoing total hip arthroplasty for ONFH. Seven patients with seven hips who received shockwave prior to surgery were designated as the study group, whereas, seven patients with seven hips who did not receive shockwave were assigned to the control group. Both groups showed similar demographic characteristics. The femoral heads were investigated with histopathological examination and immunohistochemical analysis with von Willebrand factor (vWF), VEGF, platelet endothelial cell adhesion molecule-1 (PECAM-1) also referred to as (CD 31) and vascular cell adhesion molecule (VCAM) for angiogenesis, and with proliferation cell nuclear antigen (PCNA), Dickkopf-1 (DKK1) and Winless 3a (Wnt 3) for bone remodelling and regeneration.

In histopathological examination, the study group showed significantly more viable bone and less necrotic bone, higher cell concentration and more cell activities including phagocytosis than the control group. In immunohistochemical analysis, the study group showed significant increases in vWF (P< 0.01), VEGF (P¼0.0012) and CD 31 (P¼0.0023), Wnt3 (P¼0.008) and PCNA (P¼0.0011), and decreases in VCAM (P¼0.0013) and DKK1 (P¼0.0007) than the control group.

Shockwave treatment significantly promotes angiogenesis and bone remodelling than the control. It appears that application of shockwave results in regeneration effects in hips with ONFH.

Introduction Posterior cruciate ligament (PCL) reconstruction has been shown to restore the posterior stability of the knee during posterior drawer tests. However, we have previously published a report showing that a PCL deficient knee has abnormal rotation under load. We hypothesise that a PCL reconstruction does not restore rotational stability to the knee.

Methods In-vitro kinematics under simulated muscle loads after PCL reconstruction were measured. Eight fresh-frozen cadaveric knees were tested on a robotic testing system. The system applied a posterior drawer of 130N and a combined quadriceps/hamstrings load (400N/200N) at 0°, 30°, 60°, 90°, and 120° of flexion. Tibial motion with respect to the femur was measured with the PCL intact, resected and reconstructed using an Achilles tendon allograft. Posterior tibial translation (PTT) and internal/external rotation were analyzed using a repeated measures ANOVA.

Results PCL deficiency significantly increased (p< 0.05) PTT under posterior drawer. Reconstruction significantly reduced the increased PTT to the level of the intact knee at all flexion angles. Under the muscle load, the deficiency resulted in significantly higher PTT at 60 to 120, and reconstruction did not significantly reduce the increased PTT. PCL deficiency significantly increased external rotation at 90° and 120°. PCL reconstruction did not significantly reduce the increased external rotation caused by PCL deficiency.

Conclusions Under simulated muscle loading, PCL reconstruction did not restore the translation and rotation of the tibia, despite restoring posterior stability under posterior drawer. Our data may help to identify the biomechanical factors that lead to the long-term development of osteoarthritis following PCL injury and reconstruction.

In relation to the conduct of this study, one or more of the authors is in receipt of a research grant from a non-commercial source.

Introduction: Core binding factor 1 (Cbfa1) is one of the most important transcription factors that direct the osteogenesis of mesenchymal stem cells and osteoblastic functions. It is likely that the factors controlling Cbfa1 expression would trigger the early steps of osteoblast differentiation.

Materials and Methods: By using reporter gene assay for 4.5 kb Cbfa1 promoter, it was found that the first 320 bp of Cbfa1 promoter are active in D1 cells. Within this region, electromobility shift assays delineated a 6 bp of CACATG bound specifically by the proteins from D1 cell nuclear extract. Antibody super-shift and DNA-coupling magnetic bead pull-down assay indicated that the protein bound to this sequence is USF2. Site-specific mutagenesis revealed that this sequences contributed mainly to the activity of 320 bp Cbfa1 promoter.

Discussion: In conclusion, USF2 is the major regulator for the expression of Cbfa1 gene.