Decal bone matrix as a local antibiotic delivery vehicle in a MRSA-infected bone model: An experimental study

Background:

Polymethyl methacrylate (PMMA) antibiotic beads though have proved their utility as a local antibiotic delivery system, however, there are limitations. Decalcified bone matrix (DBM) as a vehicle of antibiotics can serve the purpose, provided a minimum inhibitory concentration is sustained. Healing of the defect and avoiding the second surgery is another advantage. We studied the DBM as the delivery vehicle for vancomycin in controlling the methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis as well as healing of the cavity simultaneously in an experimental study.

Materials and Methods:

An in vitro study was conducted to optimize vancomycin impregnation in the DBM. For the in vivo study, a unicortical defect was created in the metaphysis of the distal femur in 18 rabbits. After contaminating the defect with MRSA, rabbits were divided into three groups. Group I (eight limbs) received no graft. Defects in group II (11 limbs) were filled with plain DBM chips and in group III (14 limbs), cavities were implanted with vancomycin-impregnated decal bone chips. Rabbits were assessed by clinical, radiological, histological, gross examination and bacterial load assay. High Performance Liquid Chromatography HPLC analysis of vancomycin in group III was done to assess the concentration in DBM chips.

Results:

In group I, the infection persisted throughout the period of the study. Group II showed the fulminated infection at the grafted site with DBM chips sequestrating out. Vancomycin-impregnated decal chips in group III did not show any sign of infection and eventually incorporated. The bacterial load study showed a progressive load change and HPLC revealed an effective antibiotic concentration up to 3 weeks in both in vitro and in vivo.

Conclusion:

Decal bone chips were effective as the local antibiotic delivery vehicle in preventing the MRSA osteomyelitis model. It eluted vancomycin significantly and the graft uptake was also excellent. Allogeneic decal grafts eliminated the need for second surgery and acted as an excellent delivery vehicle for antibiotics.     

Short-term intravenous antimicrobial prophylaxis in combination with preoperative oral antibiotics on surgical site infection and methicillin-resistant <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> infection in elective colon cancer surgery: Results of a prospective randomized trial

Purpose  

We performed a prospective randomized study to assess the effectiveness of short-term intravenous antimicrobial prophylaxis in combination with preoperative oral antibiotics on a surgical site and methicillin-resistant Staphylococcus aureus (MRSA) infection in elective colon cancer surgery.     

Mit Gentamicin oder Levofloxacin gesättigter Kollagenhydroxyapatit (Healos®)

Background

The functions of synthetic bone graft substitutes include not only structural support to provide bone healing and osseous ingrowth but also the ability to serve as a local antibiotic delivery system to prevent or treat infections of the spine.

Material and Methods

The impregnation and antibiotic efficiency of gentamicin and levofloxacin with Healos was investigated in vitro and compared with Healos without an antibiotic additive. These antibiotic-loaded bone graft substitutes were examined without dilution and with 10-fold and 100-fold dilution for activity against spondylodiscitis-causing bacteria on different agar plates using an agar diffusion method.

Results

All hydroxyapatite (HA)/collagen-saturated diluted antibiotics showed elliptical inhibition zones on the corresponding agar plates. For both antibiotics, there was a linear correlation between dilution and area of the inhibition zone.

Conclusion

The analysis showed that the antimicrobial activity of HA/collagen-saturated antibiotics corresponded to the antimicrobial dilutions. These results should be further analyzed using in vivo studies to determine the remaining antibiotic efficiency after implantation of bone graft substitutes.     

Does Using Autograft Bone Chips Achieve Consistent Bone Ingrowth in Primary TKA?

Background  

Cementless fixation remains controversial in TKA due to the challenge of achieving consistent skeletal attachment. Factors predicting durable fixation are not clearly understood, but we presumed bone ingrowth could be enhanced by the quantity of host bone and application of autograft bone chips.     

Questions about the use of antibiotics in acute pancreatitis

Background and objective  

The use of antibiotics in acute pancreatitis despite recent clinical trials remains controversial. The aim of this study is to review the latest clinical trials and guidelines about antibiotics in acute pancreatitis and determine its proper use.     

Effect of storage temperature and antibiotic impregnation on the quantity of bone morphogenetic protein seven in human bone grafts

Purpose

The aim of this study was to quantify the amount of bone morphogenic protein 7 (BMP-7) in bone samples in different storage and treatment conditions used in bone banks and thereby evaluate the benefit of this test as a routine measure before bone grafting.

Methods

Fresh as well as frozen bone chips, each with and without antibiotic impregnation, were screened for their BMP-7 content. Human bone chips were produced from femoral heads of two female donors who had undergone total hip replacement surgery. The amount of BMP-7 was detected using a commercially available enzyme-linked immunosorbent assay (ELISA) test.

Results

There were no significant differences between groups in samples obtained from the first femoral head. Bone-chip samples derived from the second femoral head showed significant differences between groups. The actual amount of these differences was small and most likely biologically irrelevant. It is important to note that there was a significant difference between groups when comparing both femoral heads, reflecting donor-to-donor variability.

Conclusion

ELISA testing for BMP-7 as a qualitative measurement of bone grafts should be considered a routine quality-control test for bone banks.     

Local transplantation of bone marrow concentrated granulocytes precursors can cure without antibiotics infected nonunion of polytraumatic patients in absence of bone defect

Purpose

Infected, long bone non-unions present a significant clinical challenge. New and alternative therapies are needed to address this problem. The purposes of this study were to compare the number of circulating granulocyte-macrophage colony-forming units (CFU-GM) in the peripheral blood of polytraumatic patients with infected tibial non-unions and in the peripheral blood of control patients with the hypothesis that their number was decreased in polytraumatic patients; and to treat their infection without antibiotics and with local transplantation of bone marrow concentrated granulocytes precursors.

Methods

Thirty (18 atrophic and 12 hyperthrophic ) infected tibial non-unions (without bone defect) that occurred after open fractures in polytraumatic patients were treated without antibiotics and with percutaneous injection of autologous bone marrow concentrate (BMC) containing granulocytes precursors (CFU-GM). CFU-GM progenitors were assessed in the bone marrow aspirate, peripheral blood, and fracture site of these patients. The number of these progenitors was compared with the CFU-GM progenitors of control patient samples (healthy donors matched for age and gender). Outcome measures were: timing of union, callus formation (radiographs and CT scan), and recurrence of clinical infection.

Results

As compared to control patients, the number of CFU GM derived colonies was lower at peripheral blood in patients with infected nonunions. The bone marrow graft injected in nonunions contained after concentration 42 621?±?20 350 CFU-GM-derived colonies/cc. Healing and cure of infection was observed at six months for 25 patients and at one year follow up for 30 patients. At the median ten year follow-up (range: 5 to 15), only one patient had clinical recurrent infection after healing (between 6 months and last follow-up).

Conclusion

The peripheral blood of these polytraumatic patients with infected nonunions had a remarkable decrease in CFU-GM-derived colonies as compared with normal controls. Local transplantation of concentrated CFU-GM-derived colonies aspirated from bone marrow allowed cure of infection and healing without antibiotics.

     

Non tuberculous mycobacteria in surgical wounds- a rising cause of concern?

Introduction  

The non-tuberculous mycobacteria (NTM) have emerged as important opportunistic pathogens in the recent years. The NTM are rapid growing mycobacteria (RGM), which include Mycobacterium fortuitum and M. chelonae and are grouped as M. fortuitum-chelonae complex. Non-healing postoperative wound infections that do not respond to antibiotics used for pyogenic infections and having sterile routine aerobic cultures should raise a suspicion of NTM.     

Effect of Bone Cement Thickness on the Risk of Scalded Skin in Joint Surgery

Objective

Bone cement releases a large amount of heat as it polymerizes. Skin burns caused by discarded bone cement are not well understood during arthroplasty. It is important to study the correlates and mechanisms of scalding and to accurately evaluate the severity of burns to guide treatment decisions.

Methods

Standardized burns were created in eight anesthetized rabbits using different thicknesses of bone cement. Bone cement was uniformly stirred to make thicknesses of 1 mm, 4 mm, 8 mm, 12 mm, 16 mm, and 20 mm and a 20 × 40 mm cuboid. Bone cement samples were then placed on the back of a rabbit, and the temperature changes were recorded with an industrial digital thermometer. One hour later, the appearance of scalded skin was observed, and the rabbits were euthanized. The scalded parts were cut to make pathological sections and stained with HE, and the differences in the depth of the scalded skin caused by different thicknesses of bone cement were observed under a light microscope.

Results

Damage caused by 1 mm-, 4 mm-, 8 mm-, 12 mm-, 16 mm-, and 20 mm-thick bone cement samples mainly involved the epidermis, the papillary dermis, the reticular dermis layer, and the full thickness of the skin and the subcutaneous tissue. The maximum temperature of 1 mm, 4 mm, 8 mm, and 12 mm bone cementation had a statistically significant difference (p < 0.001), while there was no significant difference between 12 mm, 16 mm, and 20 mm samples (p = 0.856). The time to severe scalding with bone cement at temperatures above 70°C was significantly different between different thicknesses (p < 0.001).

Conclusion

The heat released by different thicknesses of bone cement leads to different maximum temperatures and the duration of severe burns, resulting in different degrees of skin burns. Attention should be paid to discarded bone cement to prevent this potential complication in knee arthroplasty.     

Increased Antibiotic Release from a Bone Cement Containing Bacterial Cellulose

Background  

Major disadvantages of antibiotic bone cements include limited drug release and reduced strength resulting from the addition of high doses of antibiotics. Bacterial cellulose, a three-dimensional hydrophilic mesh, may retain antibiotics and release them gradually. We hypothesized that the addition of cellulose to antibiotic bone cement would improve mechanical strength and antibiotic release.     

Improving the human–robot interface for telemanipulated robotic long bone fracture reduction: Joystick device vs. haptic manipulator

Objectives

Intramedullary nailing is the treatment of choice for femoral shaft fractures. However, there are several problems associated with the technique, e.g. high radiation exposure and rotational malalignment. Experimental robotic assistance has been introduced to improve the quality of the reduction and to reduce the incidence of rotational malalignment. In the current study, we compare two devices for control of the fracture fragments during telemanipulated reduction.

Methods

Ten male and ten female subjects were asked to participate as examiners in this experiment. A computer program was developed to render and manipulate CT‐based renderings of femur fracture bone fragments. The user could manipulate the fragments using either a simple joystick device or a haptic manipulator. Each examiner performed telemanipulated reduction of 10 virtual fracture models of varying difficulty with each device (five in a ‘training phase’ and five in a ‘testing phase’). Mixed models were used to test whether using the haptic device improved alignment accuracy and improved reduction times compared to using a joystick.

Results

Reduction accuracy was not significantly different between devices in either the training phase or the testing phase (P > 0.05). Reduction time was significantly higher for the Phantom device than for the Joystick in the training phase (P < 0.0001), but it was no different in the testing phase (P = 0.865). High spatial ability with electronics had a significant effect on the alignment of fracture reduction and time to reduction.

Conclusions

The Joystick and the Phantom devices resulted in similarly accurate reductions, with the Joystick having an easier learning curve. The Phantom device offered no advantage over the Joystick for fracture telemanipulation. Considering the high cost of the Phantom device and the lack of a demonstrable advantage over the Joystick, its use is not justified for implementation in a fracture telemanipulation workflow. The Joystick remains as a low‐cost and effective device for developing 3D fracture telemanipulation techniques.     

Bone status in a mouse model of genetic hemochromatosis

Summary  

Genetic hemochromatosis is a cause of osteoporosis; mechanisms leading to iron-related bone loss are not fully characterized. We assessed the bone phenotype of HFE ^−/− male mice, a mouse model of hemochromatosis. They had a phenotype of osteoporosis with low bone mass and alteration of the bone microarchitecture.     

Cancel that PICC line order; cholecystostomy tube and short course of antibiotics

Background

Current guidelines do not specifically address optimal antibiotic duration following cholecystostomy. This study compares outcomes for short-course (<7 days) and long-course (≥7 days) antibiotics post-cholecystostomy.

<Emphasis Type="Italic">UGT2B17</Emphasis> gene deletion associated with an increase in bone mineral density similar to the effect of hormone replacement in postmenopausal women

Summary  

UGT2B17 is one of the most important enzymes for androgen metabolism. In addition, the UGT2B17 gene is one of the most commonly deleted regions of the human genome. The deletion was previously found associated with higher femoral bone density in men and women, and we replicated this association in a sample of postmenopausal who never used hormone therapy.     

The Exeter method—acetabular impaction grafting with cemented reimplantation

Objective

Restoration of acetabular anatomy and biomechanics at revision hip surgery by replacing deficient acetabular bone through impaction of allograft and/or autograft bone chips.

Indications

Aseptic loosening of the socket due to osteolysis, bone loss from infection, iatrogenic bone loss due to implant removal, and in the primary setting protrusio acetabuli, dysplasia and previous acetabular fracture.

Contraindications

Large segmental peripheral acetabular defects which cannot be contained, the presence of untreated infection, unstable acetabular fractures, previous radiotherapy to the affected hip area.

Surgical technique

Sound exposure of the acetabulum with delineation of the bony defect. Creation of a host environment suitable for bone graft and containment of segmental defects using rim mesh or porous augments. Impaction grafting using layered allograft or autograft bone chips of 0.8–1 cm³, packed using hemispherical impactors, followed by cementing of a polyethylene acetabular component with pressurisation.

Postoperative management

Partial weight bearing 6 weeks, modified depending on level of containment and intra-operative findings.

Results

A successful and reproducible technique with survival up to 87?% at 20 years for aseptic loosening in the revision setting.     

Prospective observational study to assess the need for postoperative antibiotics following surgical incision and drainage of skin and soft tissue abscess in pediatric patients

Background

Post-operative antibiotics are often utilized for skin and soft tissue infection (SSTI) requiring surgical incision and drainage (I&D). We propose that antibiotics are unnecessary following I&D.

Reconstruction de la voûte crânienne à l’aide de prothèses vitrocéramiques sur mesure

Background and purpose

Reconstruction of a cranial vault after craniectomy is an esthetic and functional challenge. The quest for the ideal implant that would mimic an original bone graft has tested many materials such as bone implants and artificial substitutes. The aim of this multicenter study was to report a set of preliminary results of cranioplasty using bioceramic implants made of Bioverit^® II.

Methods

In this retrospective study, we attempted to assess the esthetic results of prefabricated Bioverit^® II prostheses and to determine their performance in reducing operating time and surgical complications in delayed cranioplasty.

Results

Within a 3-year period, 16 patients from four French university hospitals underwent cranial reconstruction using this technique. The results were encouraging, with all patients showing a good esthetic outcome. Hospital length of stay after surgery was short (median, 5.5 days). One prosthesis had to be reshaped during surgery. Only one patient experienced superficial wound infection successfully treated without removing the material.

Conclusions

CAD/CAM-fabricated Bioverit^® II prostheses are a good alternative when autologous bone is not available. Fabrication of bioceramic prostheses using this method requires surgical scheduling, which is justified by the following advantages: reduced operating time, lack of donor morbidity, good esthetic results, and stability. The only drawback of this material is its price, which can limit its deployment.     

Microstructure and biomechanical characteristics of bone substitutes for trauma and orthopaedic surgery

Background  

Many (artificial) bone substitute materials are currently available for use in orthopaedic trauma surgery. Objective data on their biological and biomechanical characteristics, which determine their clinical application, is mostly lacking. The aim of this study was to investigate structural and in vitro mechanical properties of nine bone substitute cements registered for use in orthopaedic trauma surgery in the Netherlands.     

War-related infected tibial nonunion with bone and soft-tissue loss treated with bone transport using the Ilizarov method

Patients and methods  

This single centre retrospective study reviews the outcomes of 30 war-injured patients with established infected tibial nonunion after sustaining grade IIIB open fractures. Patients were treated by radical bony and soft-tissue resection and bone transport using the Ilizarov bifocal technique, without the use of systemic antibiotics or bone grafting.