Segmental bone transport (SBT) using an external fixator is currently a standard treatment for large-diameter bone defects at the donor site with low morbidity. However, long-term application of the device is needed for bone healing. In addition, patients who received SBT treatment sometimes fail to show bone repair and union at the docking site, and require secondary surgery. The objective of this study was to investigate whether a single injection of recombinant human bone morphogenetic protein 2 (rhBMP-2)-loaded artificial collagen-like peptide gel (rhBMP-2/ACG) accelerates consolidation and bone union at the docking site in a mouse SBT model. Six-month-old C57BL/6J mice were reconstructed by SBT with external fixator that has transport unit, and a 2.0-mm bone defect was created in the right femur. Mice were divided randomly into four treatment groups with eight mice in each group, Group CONT (immobile control), Group 0.2mm/d, Group 1.0mm/d, and Group BMP-2. Mice in Group 0.2mm/d and 1.0mm/d, bone segment was moved 0.2 mm per day for 10 days and 1.0 mm per day for 2 days, respectively. Mice in Group BMP-2 received an injection of 2.0 μg of rhBMP-2 dissolved in ACG into the bone defect site immediately after the defect-creating surgery and the bone segment was moved 1.0 mm/day for 2 days. All animals were sacrificed at eight weeks after surgery. Consolidation at bone defect site and bone union at docking site were evaluated radiologically and histologically. At the bone defect site, seven of eight mice in Group 0.2mm/d and two of eight mice in Group 1.0mm/d showed bone union. In contrast, all mice in Group CONT showed non-union at the bone defect site. At the docking site, four of eight mice in Group 0.2 mm/d and three of eight mice in Group 1.0 mm/d showed non-union. Meanwhile, all mice in Group BMP-2 showed bone union at the bone defect and docking sites. Bone volume and bone mineral content were significantly higher in Group 0.2mm/d and Group BMP-2 than in Group CONT. HE staining of tissue from Group 0.2mm/d and Group BMP-2 showed large amounts of longitudinal trabecular bone and regenerative new bone at eight weeks after surgery at the bone defect site. Meanwhile, in Group CONT and Group 1.0mm/d, maturation of regenerative bone at the bone defect site was poor. Differences between groups were analyzed using one-way ANOVA and a subsequent Bonferroni's post-hoc comparisons test. P < 0.05 was considered significant. rhBMP-2/ACG combined with SBT may be effective for enhancing bone healing in large bone defects without the need for secondary procedures.
Segmental bone transport (SBT) with an external fixator has become a standard method for treatment of large bone defect. However, a long time-application of devices can be very troublesome and complications such as nonunion is sometimes seen at docking site. Although there have been several studies on SBT with large animal models, they were unsuitable for conducting drug application to improve SBT. The purpose of this study was to establish a bone transport model in mice. Six-month-old C57BL/6J mice were divided randomly into bone transport group (group BT) and an immobile control group (group EF). In each group, a 2-mm bone defect was created in the right femur. Group BT was reconstructed by SBT with external fixator (MouseExFix segment transport, RISystem, Switzerland) and group EF was fixed simply with unilateral external fixator (MouseExFix simple). In group BT, a bone segment was transported by 0.2 mm per day. Radiological and histological studies were conducted at 3 and 8 weeks after the surgery. In group BT, radiological data showed regenerative new bone consolidation at 8 weeks after the surgery, whereas high rate of nonunion was observed at the docking site. Histological data showed intramembranous and endochondral ossification. Group EF showed no bone union. In this study, experimental group showed good regenerative new bone formation and was similar ossification pattern to previous large animal models. Thus, the utilization of this bone defect mice model allows to design future studies with standardized mechanical conditions for analyzing mechanisms of bone regeneration induced by SBT.
The reduction for unstable femoral intertrochanteric fracture should be extramedullary, which means that the proximal fragment protrudes for the distal fragment. However, only few articles have compared extramedullary and intramedullary reductions in a biomechanical study. Thus, we created unstable femoral intertrochanteric fracture models using imitational bone (extramedullary and intramedullary groups, each with 12 cases) and evaluated their biomechanical stabilities. The fracture type was 31-A2 according to the AO-OTA Classification of Fractures and Dislocations and greatly lacked bone on the posterior side. We performed compression examination and evaluated stiffness. The implant used for fixation was TFNA (DePuy Synthes). We applied axial compression with 20 adduction in the standing position. Statistical analysis was performed using the Mann-Whitney
We used a polymerase chain reaction (PCR) lateral flow assay1) to rapidly diagnose joint infection. We evaluated the usefulness of multiplex-PCR (PCR lateral flow assay: PCR-LF) using detailed clinical data. A total of 35 synovial fluid samples were collected from 26 patients in whom bacterial infection was suspected, including 22 from knee joints, 11 from hip joints, and 2 from other joints. After purifying the DNA from the samples, multiplex PCR targeting two MRSA-associated genes (Aim
Method
The preparation of antibiotic-containing polymethyl methacrylate (PMMA), as spacers generates a high polymerization heat, which may affect their antibiotic activity; it is desirable to use bone cement with a low polymerization heat. Calcium phosphate cement (CPC) does not generate heat on polymerization, and comparative elution testings are reported that vancomycin (VCM)-containing CPC (VCM-CPC) exceeded the antibiotic elution volume and period of PMMA (VCM-PMMA). Although CPC alone is a weak of mechanical property spacer, the double-layered, PMMA-covered CPC spacer has been created and clinically used in our hospital. In this study, we prepared the double-layered spacers: CPC covered with PMMA and we evaluated its elution concentration, antimicrobial activity and antibacterial capability. We prepared spherical, double-layered, PMMA-coated (CPC+PMMA; 24 g CPC coated with 16 g PMMA and 2 g VCM) and PMMA alone (40 g PMMA with 2 g VCM) spacers (5 each). In order to facilitate VCM elution from the central CPC, we drilled multiple holes into the CPC from the spacer surface. Each spacer was immersed in phosphate buffer (1.5 mL/g of the spacer), and the solvent was changed daily. VCM concentrations were measured on days 1, 3, 7, 14, 28, 56, and 84. Antimicrobial activity against MRSA and MSSA was evaluated by the broth microdilution method. After measuring all the concentration, the spacers were compressed at 5 mm/min and the maximum compressive load up to destruction was measured.Aim
Method
Residual stress remains in bone tissues after press-fit-fixation of a joint prosthesis, recently employed for joint arthroplasty. The response of bone tissues to the residual stress is, however, unknown because it is not physiological. This unnatural stimulus may have adverse effects on bone tissues, including causing thigh pain or bone resorption. In the present study, we designed an experimental method to apply a stationary load from inside an animal femur using a loop spring of titanium alloy with super elasticity. The femoral response was assessed based on the migration of the wire into bone twelve weeks after implantation. As the results, wire migration was noted in 10 of 11 cases. We developed a method using a loop spring made of super elastic titanium alloy, which can maintain sufficient stress in a rat femur for a prolonged period. This titanium alloy, which contains 43.94% titanium and 56.06% nickel, was supplied as a wire (WDL1, Actment Co., Ltd., Kasukabe, Japan). In the present study, an experimental method was designed to apply a stationary load from inside a rat femur by inserting a loop spring made of super elastic wire.Background
Methods
Proximal humeral fracture occurs most frequently in elderly and usually unite within 12 weeks. Malunion is more common than nonunion. And even if nonunion occurs, we usually treat it by the blade plate. Norris et al. reported hemiarthroplasty is indicated for severe degenerative changes of the articular surface, osteonecrosis of the humeral head, or osteopenia severe enough to jeopardize fixation in order patients. Therefore, it is not common that hemiarthroplasty is used for primary treatment of the proximal humeral pseudoarthrosis. We report a case of proximal humerus pseudoarthrosis which was treated by hemiarthroplasty. A patients is 75 years old male. He was injured by falling from ladder. He was diagnosed proximal humeral fracture Neer type2. After he was followed conservatively for one year, he was referred to our hospital. In X-ray film and CT, the humeral head was scraped by the humeral shaft that was tucked inward to humeral head.(Figure 1) In MRI, rotator cuff muscles were left. The fatty infiltration was stage 1 in the Gourtallier classification. (Figure 2)And osteoarthritis of shoulder was not so severe. Therefore, we decided to do hemiarthroplasty. We used the SMR implant (Lima Corporate, Milano, Italy). Surgical reconstruction was done using a deltpectral approach. Lesser tuberosity was cut from greater tuberosity with subscaplaris muscle. We used the cementless stem. Each fragments and stem was fixed using FiberWire (Arthrex, Florida USA), after autograft which scraped from the reseceted humeral head was stuffed. After the operation, the shoulder was fixed by brace for 4weeks. The passive ROM exercise was started from 21 days later. The Active ROM exercise was started at 28 days later. Three months later, the pseudoarthrosis united successfully. (Figure 3) The active flexion was improved from 20 degrees to 110 degrees. The active abduction was from 20 degrees to 90 degrees. USLA score was improved from 10 to 26.Introduction
Case
According to proposal of Noble, the femoral bone marrow cavity form of patients who underwent Total Hip Arthroplasty (THA) can be classified under 3 categories; those are Stovepipe, Normal and Champagne-fluted. We developed typical sodium chloride femoral model was created by 3D prototyping technique. The purpose was to identify the relationship of pressure zone of the surrounding areas between femoral bone marrow cavity form and hip stem. As opponent clarified stem design concept Zweymüller type model was used. According to CT data with the patients who underwent THA, the sodium chloride femoral model was custom-made and selected as the representative model based on Noble's 3 categories. Eight models of each category were used to performed mechanical test.Introduction
Materials and Method
Over the past decade, the use of negative pressure wound therapy (NPWT) devices has increased and expanded to include a wide variety of patients. However, the safety and efficacy of NPWT over skin in open fractures is still unknown. The purpose of this study was to evaluate the complication rate and outcome of open fractures treated by NPWT over closed wounds or flaps. We performed a retrospective review of prospectively collected data of 10 patients, with an average age of 37.9 years old, who underwent NPWT over surgically closed wounds or random pattern cutaneous flaps in open fractures. All wounds were debrided and closed, and NPWT was applied over the skin sequentially in emergency operations.Introduction
Materials and methods
