Prevention of infection in external fixator pin sites

Role of Dithiothreitol in Detection of Orthopaedic Implant-Associated Infections

Orthopaedic implant-associated infections (OIAIs) represent a notable complication of contemporary surgical procedures, exerting a considerable impact on patient outcomes and escalating healthcare expenditures. Prompt diagnosis holds paramount importance in managing OIAIs, with sonication widely acknowledged as the preferred method for detecting biofilm-associated infections. Recently, dithiothreitol (DTT) has emerged as a potential substitute for sonication, owing to its demonstrated ability to impede biofilm formation. This study aimed to compare the efficacy of DTT with sonication in identifying microorganisms within implants. Conducted as a prospective cohort investigation, the study encompassed two distinct groups: patients with suspected infections undergoing implant removal (Group A) and those slated for hardware explantation (Group B). Hardware segments were assessed for biofilm-related microorganisms using both sonication and DTT, with a comparative analysis of the two methods. A total of 115 patients were enrolled. In Group A, no statistically significant disparity was observed between DTT and sonication. DTT exhibited a sensitivity of 89.47% and specificity of 96.3%. Conversely, in Group B, both DTT and sonication fluid cultures yielded negative results in all patients. Consequently, this investigation suggests that DTT holds comparable efficacy to sonication in detecting OIAIs, offering a novel, cost-effective, and readily accessible diagnostic modality for identifying implant-associated infections.

"No Care Pin Care" Following Charcot Reconstruction With Static External Fixation

Charcot reconstruction with static external fixation provides stability in deformity correction. Concern for pin site health remains forefront to prevent premature fixator removal should infection develop. While previous investigations examined a spectrum of pin care protocol with a similar variation in outcomes, this study assesses results following a "no care pin care" routine. A retrospective analysis of patients with Charcot neuroarthropathy treated with static external fixation was performed where all pin sites were dressed using a chlorhexidine-soaked sponge without postoperative maintenance. Demographics, reconstruction-specific, and postoperative variables including pin site irritation, pin site infection, and pin tract infection were collected through frame removal. A comparison between uncomplicated and complicated pin sites was made. Statistical significance was set as p ≤ .05. Among 85 patients and their respective pin holes that posed potential spots of infection, 6 (7%) experienced pin site irritation and 5 (6%) experienced pin site infection. Moreover, 2 (2%) experienced a pin tract infection requiring removal. Out of the 768 wires/half-pins 2 (0.3%) were removed. There existed no statistically significant predictors of pin site irritation/infection other than age (p = .03). "No care pin care" proves an effective means at pin site care following static external fixation in Charcot reconstruction. Limited maintenance reduces the postoperative burden on providers and patients.

Clinical Outcome following Management of Severe Osteomyelitis due to Pin Site Infection

Aim

This study has investigated cases of pin site infection (PSI) which required surgery for persistent osteomyelitis (OM) despite pin removal.

Materials and methods

Patients requiring surgery for OM after PSI between 2011 and 2021 were included in this retrospective cohort study. Single-stage surgery was performed in accordance with a protocol at one institution. This involved deep sampling, debridement, implantation of local antibiotics, culture-specific systemic antibiotics and soft tissue closure. A successful outcome was defined as an infection-free interval of at least 24 months following surgery.

Results

Twenty-seven patients were identified (the sites were 22 tibias, 2 humeri, 2 calcanei, 1 radius); about 85% of them were males with a median age of 53.9 years. The majority of infections (21/27) followed fracture treatment. Fifteen patients were classified as BACH uncomplicated and 12 were BACH complex. Staphylococci were the most common pathogens, polymicrobial infections were detected in five cases (19%). Seven patients required flap coverage which was performed in the same operation.After a median of 3.99 years (2.00-8.05) follow-up, all patients remained infection free at the site of the former OM. Wound leakage after local antibiotic treatment was seen in 3/27 (11.1%) cases but did not require further treatment.

Conclusion

Osteomyelitis after PSI is uncommon but has major implications for the patient as 7 patients needed flap coverage. This reinforces the need for careful pin placement and pin site care to prevent deep infection. These infections were treated in accordance with a protocol and were not managed simply by curettage. All patients treated in this manner remained infection-free after a minimum follow-up of 2 years suggesting that this protocol is effective.

Clinical significance

Pin site infection is a very common complication in external fixation. The sequela of a chronic pin site OM is rare but the implications to the patient are huge. In this series, more than a quarter of patients required flap coverage as part of the treatment of the deep infection.

How to cite this article

Frank FA, Pomeroy E, Hotchen AJ, et al. Clinical Outcome following Management of Severe Osteomyelitis due to Pin Site Infection. Strategies Trauma Limb Reconstr 2024;19(1):21-25.

Highly Adhesive Antimicrobial Coatings for External Fixation Devices

Pin site infections arise from the use of percutaneous pinning techniques (as seen in skeletal traction, percutaneous fracture pinning, and external fixation for fracture stabilization or complex deformity reconstruction). These sites are niduses for infection because the skin barrier is disrupted, allowing for bacteria to enter a previously privileged area. After external fixation, the rate of pin site infections can reach up to 100%. Following pin site infection, the pin may loosen, causing increased pain (increasing narcotic usage) and decreasing the fixation of the fracture or deformity correction construct. More serious complications include osteomyelitis and deep tissue infections. Due to the morbidity and costs associated with its sequelae, strategies to reduce pin site infections are vital. Current strategies for preventing implant-associated infections include coatings with antibiotics, antimicrobial polymers and peptides, silver, and other antiseptics like chlorhexidine and silver-sulfadiazine. Problems facing the development of antimicrobial coatings on orthopedic implants and, specifically, on pins known as Kirschner wires (or K-wires) include poor adhesion of the drug-eluting layer, which is easily removed by shear forces during the implantation. Development of highly adhesive drug-eluting coatings could therefore lead to improved antimicrobial efficacy of these devices and ultimately reduce the burden of pin site infections. In response to this need, we developed two types of gel coatings: synthetic poly-glycidyl methacrylate-based and natural-chitosan-based. Upon drying, these gel coatings showed strong adhesion to pins and remained undamaged after the application of strong shear forces. We also demonstrated that antibiotics can be incorporated into these gels, and a K-wire with such a coating retained antimicrobial efficacy after drilling into and removal from a bone. Such a coating could be invaluable for K-wires and other orthopedic implants that experience strong shear forces during their implantation.

Efficacy of Antibiotic Cement in Preserving Endoplants After Infection With Plate Exposure

Background: To study the feasibility and efficacy of antibiotic cement in preserving endoplants after infection in patients with early tibial plateau fracture on plate exposure. Patients and Methods: A retrospective analysis of 23 patients treated for post-operative infection with plate exposure after tibial plateau fracture between 2017 and 2021. They were divided into the observation group (10 patients) and the control group (13 patients). Total operation time, length of hospitalization, hospitalization cost, the number of surgeries, white blood cell (WBC) count, neutrophil (NEUT) count, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), the post-operative evaluation index, and complications were observed during the follow-up period. Results: All patients were followed up for 6 to 12 months; wound healing was observed in both groups. The total operation time for patients in the control group was longer compared with the observation group. However, the length of hospitalization, hospitalization cost, and number of surgeries in the observation group were less compared with the control group. No difference in WBC, NEUT, ESR, and CRP levels was observed one day after surgery. Furthermore, WBC, NEUT, ESR, and CRP levels were higher in patients in the control group compared with the observation group 72 hours after surgery. There were no differences in the post-operative evaluation index and complications in both groups. Conclusions: The antibiotic cement coating used for treating early post-operative infection in patients with tibial plateau fracture could effectively control infection while retaining endoplant, thereby promoting wound healing. It could also reduce pain and the medical burden on patients.

Precice Stryde® Magnetic Internal Lengthening Nail does not Impair Bone Healing Despite Radiographic and Clinical Symptoms

Aims

The Precice Stryde® internal magnetic lengthening nail allowed many patients a full weight-bearing experience during femur and tibia lengthening, but concerns over corrosion, pain and radiographic changes led to the implant's recall. Despite the recall, it is important to understand the rate of these occurrences and their influence on the overall success of the lengthening procedure. We aimed to investigate radiographic changes, patient-reported symptoms and bone healing indices for our cohort of Stryde lengthening.

Materials and methods

Our surgical database and electronic medical record system were used to review and document patient demographics, indications for lengthening, length achieved, bone healing index (BHI), location and type of radiographic changes, time until radiographic changes were first visible, presence of pain symptoms (not attributable to surgery or distraction), time to implant removal and if the pain symptoms resolved following implant extraction.

Results

From January 2019 to February 2021, 90 Stryde nails (78 femur and 12 tibia) were implanted in 63 patients. The cohort included 48 males and 15 females. The average length [± standard deviation (SD)] achieved was 58.4 ± 22.7 mm. The 66 bones (73%) developed radiographic changes and were found to be 58/78 (74%) femurs and 8/12 (67%) tibias. The average time to initial radiographic changes was 168 ± 108.1 days (femur) and 276 ± 126.8 days (tibia). Late-onset pain developed in 10 femur lengthening (11.1% of all nails) surgeries across eight patients (12.7% of all patients). All patients' pain resolved; three instances prior to nail removal and the remaining seven after nail removal. No patients were re-presented with worsening pain or radiographic changes following implant removal. Radiographic or symptomatic abnormalities did not impair bone formation. The BHI for femurs with (29.6 ± 16.6 days/cm, n = 58) vs without (29.4 ± 17.9 days/cm, n = 20) radiographic or symptomatic irregularity were nearly identical (p = 0.961). The difference between BHI for tibias with (39.3 ± 7.8 days/cm, n = 8) vs without (86.1 ± 38.2 days/cm, n = 4) radiographic changes was influenced by outliers and underpowered to draw a conclusion.

Conclusion

Bone lengthening with the Stryde nail was associated with high rates of radiographic abnormalities, but symptoms were uncommon and resolved with explantation. The radiographic changes did not affect bone healing in the femur.

Clinical significance

Radiographic changes including bone hypertrophy and osteolysis were common after bone lengthening with the Stryde nail, but the development of pain following consolidation was rare and resolved with implant removal.The BHI in femurs was not affected by radiographic changes.

How to cite this article

Reif TJ, Geffner A, Hoellwarth JS, et al. Precice Stryde® Magnetic Internal Lengthening Nail does not Impair Bone Healing Despite Radiographic and Clinical Symptoms. Strategies Trauma Limb Reconstr 2023;18(2):94-99.

Dual-analgesic loaded UHMWPE exhibits synergistic antibacterial effects against Staphylococci

Total joint arthroplasty is one of the most common surgeries in the United States, with almost a million procedures performed annually. Periprosthetic joint infections (PJI) remain the most devastating complications associated with total joint replacement. Effective antibacterial prophylaxis after primary arthroplasty could substantially reduce incidence rate of PJI. In the present study we propose to provide post-arthroplasty prophylaxis via dual-analgesic loaded ultra-high molecular weight polyethylene (UHMWPE). Our approach is based on previous studies that showed pronounced antibacterial activity of analgesic- and NSAID-loaded UHMWPE against Staphylococci. Here, we prepared bupivacaine/tolfenamic acid-loaded UHMWPE and assessed its antibacterial activity against Staphylococcus aureus and Staphylococcus epidermidis. Dual-drug loaded UHMWPE yielded an additional 1-2 log reduction of bacteria, when compared with single-drug loaded UHMWPE. Analysis of the drug elution kinetics suggested that the observed increase in antibacterial activity is due to the increased tolfenamic acid elution from dual-drug loaded UHMWPE. We showed that the increased fractal dimension of the drug domains in UHMWPE could be associated with increased drug elution, leading to higher antibacterial activity. Dual-analgesic loaded UHMWPE proposed here can be used as part of multi-modal antibacterial prophylaxis and promises substantial reduction in post-arthroplasty mortality and morbidity.

Efficacy comparison of antibiotic bone cement-coated implants and external fixations for treating infected bone defects

PURPOSE

This study aimed to investigate the clinical efficacy of antibiotic bone cement-coated implants compared with external fixations for treating infected bone defects.

METHODS

We retrospectively enrolled 119 patients with infected bone defects in our hospital from January 2010 to June 2021, of which 56 were treated with antibiotic bone cement-coated implants and 63 were with external fixation.

RESULTS

The pre-operative and post-operative haematological indexes were tested to assess the infection control; the post-operative CRP level in the internal fixation group was lower than that in the external fixation group. No statistical significance was found in the rate of infection recurrence, loosening and rupture of the fixation, and amputation between the two groups. Twelve patients in the external fixation group had pin tract infection. In the evaluation of the Paley score scale, bone healing aspect revealed no significant difference between the two groups, while in the limb function aspect, antibiotic cement-coated implant group showed a much better score than the external fixation group (P = 0.002). The anxiety evaluation scale result also showed lower score in the antibiotic cement implant group (P < 0.001).

CONCLUSIONS

Compared with external fixation, antibiotic bone cement-coated implant had the same effect on controlling infection and was more effective in recovering limb function and mental health in the first-stage treatment of infected bone defects after debridement.

Hydrotherapy for Patients With External Fixation: Effect on Infectious Events

BACKGROUND

Surgery to achieve long bone lengthening and deformity correction in skeletally immature patients is traditionally performed through external fixators. The incidence of infection during treatment is high. Hydrotherapy is highly beneficial during external fixation management, but the infection rates may impact its utilization. The objective of this paper is to document the incidence and duration of infection in patients who participated in a full hydrotherapy program when performed under medical supervision and in accordance with strict follow-up protocols.

METHODS

In this retrospective study, we documented the key characteristics of patients who participated in hydrotherapy after lower limb external fixation surgery including age, sex, diagnosis and surgery site, the incidence and duration of pin site infections, and the percentage of cases, which were able to comply with a full hydrotherapy protocol.

RESULTS

The hydrotherapy pool met all daily water quality metrics. Thirty-four children (19 males and 15 females) had a mean±SD age of 10.9±4.6 years. Of the cases, 80% were unilateral and 20% were bilateral. Diagnoses included congenital hereditary (eg, achondroplasia), congenital nonhereditary conditions (eg, fibular hemimelia), and acquired conditions (eg, traumatic). The location of osteotomy site was quite evenly spread between the femur and the tibia/fibula. Three out of the 34 patients were unable to receive hydrotherapy due to continuous secretions; 2 patients did not miss any sessions. The mean number of treatments was 3 per week. During the entire period, a total of 1200 treatments were performed for these patients with only 32 cancellations (about 3%) due to secretions or other signs of infection. Spearman correlation coefficients showed significantly high correlations between the duration of external fixation and the duration of hydrotherapy. There are no significant correlations between infections and other factors (sex, age segment, whether the problem is unilateral or /bilateral, diagnosis, and duration of treatment).

CONCLUSIONS

This is the first report, to our knowledge, that documents the low prevalence of infectious events during hydrotherapy treatment and demonstrates its feasibility.

LEVEL OF EVIDENCE

Level III; retrospective, comparative study.

Hydroxyapatite-coated compared with stainless steel external fixation pins did not show impact in the rate of pin track infection: a multicenter prospective study

PURPOSE

Infection at the pin site remains the most common complication of external fixators (EFs). It is known that hydroxyapatite (HA)-coated pins increase bone adhesion and may lead to reduced rates of reported infections. The present study compares the rates of pin track infection associated with stainless steel and HA-coated pins.

METHODS

This is a prospective, multicenter, nonrandomized, comparative intervention study among patients undergoing surgical treatment with EFs of any type between April 2018 and October 2021. Patients were followed up until the removal of the EF, or the end of the study period (ranging from 1 to 27.6 months). The definition of pin track infection was based upon the Maz-Oxford-Nuffield (MON) pin infection grading system.

RESULTS

Overall, 132 patients undergoing external fixation surgery were included. Of these, 94 (71.2%) were male, with a mean age of 36.9 years (SD ± 18.9). Infection of any type (score > 1) was observed in 63 (47.7%) patients. Coated and uncoated-pin track-infection occurred in 45.7% and 48.5% of patients, respectively (P= 0.0887). The probability of developing infection (defined as a score ≥ 2) adjusted for comorbidities and follow-up time was not statistically higher among those who received uncoated pins compared to those who received pins coated with HA (odds ratio (OR) = 1.56, 95% confidence interval (95% CI): 0.67-3.67, p <0.05).

CONCLUSION

In the present study, the external fixator pin infection rates were similar when using HA coating and standard steel pins.

Enrichment of Bone Tissue with Antibacterially Effective Amounts of Nitric Oxide Derivatives by Treatment with Dielectric Barrier Discharge Plasmas Optimized for Nitrogen Oxide Chemistry

Cold atmospheric plasmas (CAPs) generated by dielectric barrier discharge (DBD), particularly those containing higher amounts of nitric oxide (NO) or NO derivates (NOD), are attracting increasing interest in medical fields. In the present study, we, for the first time, evaluated DBD-CAP-induced NOD accumulation and therapeutically relevant NO release in calcified bone tissue. This knowledge is of great importance for the development of new therapies against bacterial-infectious complications during bone healing, such as osteitis or osteomyelitis. We found that by modulating the power dissipation in the discharge, it is possible (1) to significantly increase the uptake of NODs in bone tissue, even into deeper regions, (2) to significantly decrease the pH in CAP-exposed bone tissue, (3) to induce a long-lasting and modulable NO production in the bone samples as well as (4) to significantly protect the treated bone tissue against bacterial contaminations, and to induce a strong bactericidal effect in bacterially infected bone samples. Our results strongly suggest that the current DBD technology opens up effective NO-based therapy options in the treatment of local bacterial infections of the bone tissue through the possibility of a targeted modulation of the NOD content in the generated CAPs.

A clinical and radiological matched-pair analysis of patients treated with the PRECICE and STRYDE magnetically driven motorized intramedullary lengthening nails

AIMS

Distraction osteogenesis with intramedullary lengthening devices has undergone rapid development in the past decade with implant enhancement. In this first single-centre matched-pair analysis we focus on the comparison of treatment with the PRECICE and STRYDE intramedullary lengthening devices and aim to clarify any clinical and radiological differences.

METHODS

A single-centre 2:1 matched-pair retrospective analysis of 42 patients treated with the STRYDE and 82 patients treated with the PRECICE nail between May 2013 and November 2020 was conducted. Clinical and lengthening parameters were compared while focusing radiological assessment on osseous alterations related to the nail's telescopic junction and locking bolts at four different stages.

RESULTS

Osteolysis next to the telescopic junction was observed in 31/48 segments (65%) lengthened with the STRYDE nail before implant removal compared to 1/91 segment (1%) in the PRECICE cohort. In the STRYDE cohort, osteolysis initially increased, but decreased or resolved in almost all lengthened segments (86%) after implant removal. Implant failure was observed in 9/48 STRYDE (19%) and in 8/92 PRECICE nails (9%). Breakage of the distal locking bolts was found in 5/48 STRYDE nails (10%) compared to none in the PRECICE cohort. Treatment-associated pain was generally recorded as mild and found in 30/48 patients (63%) and 39/92 (42%) in the STRYDE and PRECICE cohorts, respectively. Temporary range of motion (ROM) limitations under distraction were registered in 17/48 (35%) segments treated with the STRYDE and 35/92 segments (38%) treated with the PRECICE nail.

CONCLUSION

Osteolysis and periosteal reaction, implant breakage, and pain during lengthening and consolidation is more likely in patients treated with the STRYDE nail compared to the PRECICE nail. Temporary ROM limitations during lengthening occurred independent of the applied device. Implant-related osseous alterations seem to remodel after implant removal.Cite this article: Bone Joint J 2023;105-B(1):88-96.

Pin-site Infection: A Systematic Review of Prevention Strategies

Introduction

Circular frame fixation remains a key tool in the armamentarium of the limb reconstruction surgeon. One of the key drawbacks is the onset of pin-site infection (PSI). As a result of limited evidence and consensus of PSI prevention, a wide variation in practice remains.

Aim

The principal aim of this review is to synthesise primary research concerning all aspects of treatment regarded as relevant to PSI in frame constructs.

Materials and methods

Comparative studies until week 26, 2021, were included in the trial. Studies were included that concerned patients undergoing management of a musculoskeletal condition in which pin-site care is necessary for over 4 weeks.

Results

Eighteen studies over a 13-year period were captured using the search strategy. Sulphadiazine and hydrogen peroxide cleansing was found to reduce PSI, with the use of low-energy fine wires and hydroxyapatite (HA)-coated pins also associated with lower infection rate. The remainder of studies found no significant improvement across interventions.

Conclusion

There is no superiority between weekly and daily care. Low-energy pin-insertion technique had lower rates of infection. Sulphadiazine has positive results as a pin-care solution, but more research is necessary to determine the most effective care regime. Current literature is limited by absence of established definitions and by a lack of studies addressing all aspects of care relevant to PSI.

How to cite this article

Shields DW, Iliadis AD, Kelly E, et al. Pin-site Infection: A Systematic Review of Prevention Strategies. Strategies Trauma Limb Reconstr 2022;17(2):93–104.

Fungal-derived Selenium Nanoparticles and Their Potential Applications in Electroless Silver Coatings for Preventing Pin-tract Infections

Pin-tract infections (PTIs) are a common complication of external fixation of fractures and current strategies for preventing PTIs have proven to be ineffective. Recent advances show that the use of anti-infection coatings with local antibacterial activity may solve this problem. Selenium has been considered as a promising anti-infection agent owing to its antibacterial and antibiofilm activities. In this study, selenium nanoparticles (SeNPs) were synthesized via a cost-effective fungi-mediated biorecovery approach and demonstrated excellent stability and homogeneity. To investigate their anti-infection potential, the SeNPs were doped in silver coatings through an electroless plating process and the silver–selenium (Ag–Se) coatings were tested for antibacterial and antibiofilm properties against Staphylococcus aureus F1557 and Escherichia coli WT F1693 as well as corrosion resistance in simulated body fluid. It was found that the Ag–Se coating significantly inhibited S.aureus growth and biofilm formation on the surface, reducing 81.2% and 59.7% of viable bacterial adhesion when compared with Ag and Ag–PTFE-coated surfaces after 3 days. The Ag–Se coating also exhibited improved corrosion resistance compared with the Ag coating, leading to a controlled release of Ag⁺, which in turn reduced the risk of cytotoxicity against hFOBs. These results suggest that the fungal-derived SeNPs may have potential in use as implant coatings to prevent PTIs.

Effective Strategies to Deal With Infection in Burn Patient

Treatment of bacterial infection is difficult. Treatment protocol of burned patient is hard. Furthermore, treatment in burned patients is accompanied with problems such as complexity in diagnosis of infection's agent, multiple infections, being painful, and involving with different organelles. There are different infections of Gram-positive and Gram-negative bacteria in burned patients. From important bacteria can be noted to Pseudomonas aeruginosa, Acinetobacter baumannii, and Staphylococcus aureus that have high range of morbidity and mortality. Treatment of those bacterial infections is extremely important. Hence, many studies about methods of treatment of bacterial infections have published. Herein, we have suggested practical methods for example ant virulence therapies, nanotechnology, vaccine, and photodynamic therapy in treatment of bacterial infections. Those methods have been done in many researches and had good effect.

Role of coatings and materials of external fixation pins on the rates of pin tract infection: A systematic review and meta-analysis

BACKGROUND

Infection at the pin tract is a frequent and feared complication of external fixators (EF). The type of pin material and coatings have been regarded as possibly influencing infection rates. Over the last 20 years, few prospective clinical studies and systematic reviews addressed the role of coated pins on the rate of pin site infection in human clinical studies.

AIM

To assess the EF literature over the past 20 years on the clinical benefits of pins manufactured from varied materials and coating systems and their possible role in pin tract infection rates.

METHODS

We performed a systematic review according to the PRISMA and PICOS guidelines using four scientific platforms: PubMed, LiLacs, SciELO, and Cochrane. We searched the literature for related publications over the past 20 years.

RESULTS

A literature search yielded 29 articles, among which seven met the inclusion criteria. These studies compared stainless-steel pins and pins coated with hydroxyapatite (HA), titanium and silver. The pin tract infection definitions were arbitrary and not standardized among studies. Most studies included a low number of patients in the analysis and used a short follow-up time. Three meta-analyses were carried out, comparing stainless steel vs silver pins, stainless steel vs HA-coated pins, and titanium vs HA-coated pins. None of this analysis resulted in statistically significant differences in pin tract infection rates.

CONCLUSION

Currently, no clinical evidence supports the advantage of EF pins manufactured with materials other than stainless steel or coated over uncoated pins in reducing the rates of pin tract infections. A standardized definition of pin tract infection in external fixation is still lacking.

Electrophoretic deposition of silk fibroin coatings with pre-defined architecture to facilitate precise control over drug delivery

The therapeutic precision and clinical applicability of drug-eluting coatings can be substantially improved by facilitating tunable drug delivery. However, the design of coatings which allows for precise control over drug release kinetics is still a major challenge. Here, a double-layered silk fibroin (SF) coating system was constructed by sequential electrophoretic deposition. A mixture of dissolved Bombyx mori SF (bmSF) molecules and pre-made bmSF nanospheres at different ratios was deposited as under-layer. Subsequently, this underlayer was covered by a top-layer comprising Antheraea pernyi SF (apSF) molecules (rich in arginylglycylaspartic acid, RGD) to improve the cellular response of the resulting double-layered coatings. Additionally, model drug doxycycline was either pre-mixed with dissolved bmSF molecules or pre-loaded into pre-made bmSF nanospheres at the same amount before their mixing and deposition. The thickness and nanosphere content of the under-layer architecture were proportional to the deposition time and nanosphere concentration in precursor mixtures, respectively. The surface topography, wettability, degradation rate and adhesion strength were comparable within the double-layered coating system. As expected, RGD-rich apSF top-layer improved cell adhesion, spreading and proliferation compared with bmSF top-layer. Furthermore, the amount and duration of drug release increased linearly with increasing nanosphere concentration at fixed deposition time, whereas drug release amount increased linearly with increasing deposition time. These results indicate that the dosage and kinetics of loaded drugs can be quantitatively tailored by altering nanosphere concentration and deposition time as main processing parameters. Overall, this study illustrates the strong potential of pre-defining coating architecture to facilitate control over drug delivery.

Locking Compression Plate as an External Fixator for the Treatment of Tibia Infected Bone Defects

PURPOSE

This study was designed to observe the medium-term efficacy of an induced membrane technique combined with a locking compression plate as an external fixator for the treatment of tibia infected bone defects.

METHODS

Patients with a tibial infection were admitted to our department between January 2013 and November 2014. All patients were treated with the induced membrane technique. In the first stage, polymethyl methacrylate (PMMA) cement was implanted in the defects after debridement and then fixed with a locking compression plate (LCP) as an external fixator. In the second stage, bone grafts were implanted to rebuild the defects. The external plates were replaced with nails in 57 patients (internal group), and the remaining 30 patients were not exchanged with fixation (external group). The infection control rate, bone union rate, and complications of the two groups were compared.

RESULTS

Eighty-seven patients were enrolled in this study, and all patients had a minimum follow-up of 5 years (average 62.8 months) after grafting. Eighty-three patients (95.4%) achieved bone union, and the average union time was 6.77 months. Five patients (5.7%) experienced recurrence of infection. Complications included pin tract infection, fixation loosening, deformity connection, and limitation of joint range of motion (ROM). No significant differences in the infection control rate or bone defect union rate were noted between the two groups. The overall rate of complications in the external group was 50%, which was greater than that noted in the internal group (21.1%).

CONCLUSIONS

Locking compression plates are external fixators with smaller sizes that are easier to operate than conventional annular fixators or assembled external fixators. The use of locking compression plates in combination with the induced membrane technique in the treatment of tibia infected bone defects can achieve good clinical efficacy after medium-term follow-up.

Bacteria Single-Cell and Photosensitizer Interaction Revealed by Quantitative Phase Imaging

Quantifying changes in bacteria cells in the presence of antibacterial treatment is one of the main challenges facing contemporary medicine; it is a challenge that is relevant for tackling issues pertaining to bacterial biofilm formation that substantially decreases susceptibility to biocidal agents. Three-dimensional label-free imaging and quantitative analysis of bacteria-photosensitizer interactions, crucial for antimicrobial photodynamic therapy, is still limited due to the use of conventional imaging techniques. We present a new method for investigating the alterations in living cells and quantitatively analyzing the process of bacteria photodynamic inactivation. Digital holographic tomography (DHT) was used for in situ examination of the response of Escherichia coli and Staphylococcus aureus to the accumulation of the photosensitizers immobilized in the copolymer revealed by the changes in the 3D refractive index distributions of single cells. Obtained results were confirmed by confocal microscopy and statistical analysis. We demonstrated that DHT enables real-time characterization of the subcellular structures, the biophysical processes, and the induced local changes of the intracellular density in a label-free manner and at sub-micrometer spatial resolution.

[External fixation for treatment of peripartum pubic symphysis separation : Clinical case and discussion]

A complete peripartum pubic symphysis separation is a rare but severe complication of natural birth. Its incidence is estimated to be 0.03-3 ‰. Minor partial separations with a small width can be treated with a pelvic binder. Separations with major dehiscence should be treated by surgical reduction and fixation. This article presents the case of a 30-year-old woman who suffered a complete rupture of the pubic symphysis during the birth of her second child. Radiographic dehiscence was 39 mm. The operative treatment was carried out using a supra-acetabular external fixator for 12 weeks with a good result.

Treatment of contaminated radial fracture in Sprague-Dawley rats by application of a degradable polymer releasing gentamicin

Fracture-related infections remain a leading cause of morbidity and mortality. We aimed to establish a simple contaminated radial osteotomy model to assess the efficacy of a biodegradable polymer poly(sebacic-co-ricinoleic acid) [p(SA-RA)] containing 20% w/w gentamicin. A unilateral transverse osteotomy was induced in Sprague-Dawley (SD) rats, followed by application of Staphylococcus aureus suspension over the fracture. After successfully establishing the contaminated open fracture model, we treated the rats either systemically (intraperitoneal cefuroxime), locally with p(SA-RA) containing gentamicin, or both. Control groups included non-contaminated group and contaminated groups that were either untreated or treated with the polymer alone. After 4 weeks, the bones were subjected to micro-CT scanning and microbiological and histopathology evaluations. Micro-CT analysis revealed similar changes in the group subjected to both local and systemic treatment as in the non-contaminated control group. Lack of detectable bacterial growth was noted in most animals of the group subjected to both local and systemic treatment, and all samples were negative for S. aureus. Histopathological evaluation revealed that all treatment modalities containing antibiotics were highly effective in reducing infection and promoting callus repair, resulting in early bone healing. While p(SA-RA) containing gentamicin treatment showed better results than cefuroxime, the combination of local and systemic treatment displayed the highest therapeutic potential in this model.

A Randomized Clinical Trial on the Use of Antiseptic Solutions for the Pin-Site Care of External Fixators: Chlorhexidine-Alcohol Versus Povidone-Iodine

Pin-site infections remain a common clinical complication in patients with external fixators. Pin-site care is commonly performed with either chlorhexidine-alcohol solution or povidone-iodine solution. This study aimed to investigate the superiority of chlorhexidine-alcohol solution versus povidone-iodine solution for external fixator pin-site care in pin-site infection. This prospective randomized clinical trial using an open, parallel-group design was conducted in a single Spanish hospital. Eligible consenting patients from November 2018 to May 2019 who underwent placement of an external fixator were included. Patients were randomly assigned to receive pin-site care using either a 2% chlorhexidine-alcohol solution or a 10% povidone-iodine solution. The primary endpoint was the development of a pin-site infection. In total, 568 pins were analyzed (128 patients, with a mean of 4.3 pins per patient). No significant differences were found between groups. However, statistically significant differences were found regarding time and infection variables. The longer the person had the fixator, the higher the risk of infection, t(x) = 5.49, p = .002. Both chlorhexidine-alcohol and povidone-iodine solutions are equally effective antiseptic agents for the prevention of infections in external fixators.

Electrodeposited Assembly of Additive-Free Silk Fibroin Coating from Pre-Assembled Nanospheres for Drug Delivery

Electrophoretically deposited (EPD) polymer-based coatings have been extensively reported as reservoirs in medical devices for delivery of therapeutic agents, but control over drug release remains a challenge. Here, a simple but uncommon assembly strategy for EPD polymer coatings was proposed to improve drug release without introducing any additives except the EPD matrix polymer precursor. The added value of the proposed strategy was demonstrated by developing a novel EPD silk fibroin (SF) coating assembled from pre-assembled SF nanospheres for an application model, that is, preventing infections around percutaneous orthopedic implants via local delivery of antibiotics. The EPD mechanism of this nanosphere coating involved oxidation of water near the substrate to neutralize SF nanospheres, resulting in irreversible deposition. The deposition process and mass could be easily controlled using the applied EPD parameters. In comparison with the EPD SF coating assembled in a conventional way (directly obtained from SF molecule solutions), this novel coating had a similar adhesion strength but exhibited a more hydrophobic nanotopography to induce better fibroblastic response. Moreover, the use of nanospheres as building blocks enabled 1.38 and 21 times enhancement on the antibiotic release amount and time (of 95% maximum dug release), respectively, while retaining drug effectiveness and showing undetectable cytotoxicity. This unexpected release kinetics was found attributable to the electrostatic and hydrophobic interactions between the drug and nanospheres and a negligible initial dissolution effect on the nanosphere coating. These results illustrate the promising potential of the pre-assembled strategy on EPD polymer coatings for superior control over drug delivery.

Knee joint distraction in regular care for treatment of knee osteoarthritis: A comparison with clinical trial data

Objectives

Knee joint distraction (KJD) has been evaluated as a joint-preserving treatment to postpone total knee arthroplasty in knee osteoarthritis patients in three clinical trials. Since 2014 the treatment is used in regular care in some hospitals, which might lead to a deviation from the original indication and decreased treatment outcome. In this study, baseline characteristics, complications and clinical benefit are compared between patients treated in regular care and in clinical trials.

Methods

In our hospital, 84 patients were treated in regular care for 6 weeks with KJD. Surgical details, complications, and range of motion were assessed from patient hospital charts. Patient-reported outcome measures were evaluated in regular care before and one year after treatment. Trial patients (n = 62) were treated and followed as described in literature.

Results

Patient characteristics were not significantly different between groups, except for distraction duration (regular care 45.3±4.3; clinical trials 48.1±8.1 days; p = 0.019). Pin tract infections were the most occurring complication (70% regular care; 66% clinical trials), but there was no significant difference in treatment complications between groups (p>0.1). The range of motion was recovered within a year after treatment for both groups. WOMAC questionnaires showed statistically and clinically significant improvement for both groups (both p<0.001 and >15 points in all subscales) and no significant differences between groups (all differences p>0.05). After one year, 70% of patients were responders (regular care 61%, trial 75%; p = 0.120). Neither regular care compared to clinical trial, nor any other characteristic could predict clinical response.

Conclusions

KJD as joint-preserving treatment in clinical practice, to postpone arthroplasty for end-stage knee osteoarthritis patient below the age of 65, results in an outcome similar to that thus far demonstrated in clinical trials. Longer follow-up in regular care is needed to test whether also long-term results remain beneficial and comparable to trial data.

Off-Stoichiometric Reactions at the Cell-Substrate Biomolecular Interface of Biomaterials: In Situ and Ex Situ Monitoring of Cell Proliferation, Differentiation, and Bone Tissue Formation

The availability of osteoinductive biomaterials has encouraged new therapies in bone regeneration and has potentially triggered paradigmatic shifts in the development of new implants in orthopedics and dentistry. Among several available synthetic biomaterials, bioceramics have gained attention for their ability to induce mesenchymal cell differentiation and successive bone formation when implanted in the human body. However, there is currently a lack of understanding regarding the fundamental biochemical mechanisms by which these materials can induce bone formation. Phenomenological studies of retrievals have clarified the final effect of bone formation, but have left the chemical interactions at the cell-material interface uncharted. Accordingly, the knowledge of the intrinsic material properties relevant for osteoblastogenesis and osteoinduction remains incomplete. Here, we systematically monitored in vitro the chemistry of mesenchymal cell metabolism and the ionic exchanges during osteoblastogenesis on selected substrates through conventional biological assays as well as via in situ and ex situ spectroscopic techniques. Accordingly, the chemical behavior of different bioceramic substrates during their interactions with mesenchymal cells could be unfolded and compared with that of biomedical titanium alloy. Our goal was to clarify the cascade of chemical equations behind the biological processes that govern osteoblastogenic effects on different biomaterial substrates.

Titanium Kirschner Wires Resist Biofilms Better Than Stainless Steel and Hydroxyapatite-coated Wires: An In Vitro Study

Aim

External fixation surgery is frequently complicated by percutaneous pin site infection focused on the surface of the fixator pin. The primary aim of this study was to compare biofilm growth of clinically isolated pin site bacteria on Kirschner wires of different materials.

Materials and methods

Two commonly infecting species, Staphylococcus epidermidis and Proteus mirabilis, were isolated from patients’ pin sites. A stirred batch bioreactor was used to grow these bacteria as single culture and co-cultured biofilms on Kirschner wires made of three different materials: stainless steel, hydroxyapatite-coated steel and titanium alloy.

Results

We found that the surface density of viable cells within these biofilms was 3x higher on stainless steel and 4.5x higher on hydroxyapatite-coated wires than on the titanium wires.

Conclusion

Our results suggest that the lower rates of clinical pin site infection seen with titanium Kirschner wires are due to, at least in part, titanium’s better bacterial biofilm resistance.

Clinical significance

Our results are consistent with clinical studies which have found that pin site infection rates are reduced by the use of titanium relative to stainless steel or hydroxyapatite-coated pins.

How to cite this article

McEvoy JP, Martin P, Khaleel A, et al. Titanium Kirschner Wires Resist Biofilms Better Than Stainless Steel and Hydroxyapatite-coated Wires: An In Vitro Study. Strategies Trauma Limb Reconstr 2019;14(2):57–64.

Ion-substituted calcium phosphate coatings by physical vapor deposition magnetron sputtering for biomedical applications: A review

Coatings based on ion-substituted calcium phosphate (Ca-P) have attracted great attention in the scientific community over the past decade for the development of biomedical applications. Among such Ca-P based structures, hydroxyapatite (HA) has shown significant influence on cell behaviors including cell proliferation, adhesion, and differentiation. These cell behaviors determine the osseointegration between the implant and host bone and the biocompatibility of implants. This review presents a critical analysis on the physical vapor deposition magnetron sputtering (PVDMS) technique that has been used for ion-substituted Ca-P based coatings on implants materials. The effect of PVDMS processing parameters such as discharge power, bias voltage, deposition time, substrate temperature, and post-heat treatment on the surface properties of ion-substituted Ca-P coatings is elucidated. Moreover, the advantages, short comings and future research directions of Ca-P coatings by PVDMS have been comprehensively analyzed. It is revealed that the topography and surface chemistry of amorphous HA coatings influence the cell behavior, and ion-substituted HA coatings significantly increase cell attachment but may result in a cytotoxic effect that reduces the growth of the cells attached to the coating surface areas. Meanwhile, low-crystalline HA coatings exhibit lower rates of osteogenic cell proliferation as compared to highly crystalline HA coatings developed on Ti based surfaces. PVDMS allows a close reproduction of bioapatite characteristics with high adhesion strength and substitution of therapeutic ions. It can also be used for processing nanostructured Ca-P coatings on polymeric biomaterials and biodegradable metals and alloys with enhanced corrosion resistance and biocompatibility. STATEMENT OF SIGNIFICANCE: Recent studies have utilized the physical vapor deposition magnetron sputtering (PVDMS) for the deposition of Ca-P and ion-substituted Ca-P thin film coatings on orthopedic and dental implants. This review explains the effect of PVDMS processing parameters, such as discharge power, bias voltage, deposition time, substrate temperature, and post-heat treatment, on the surface morphology and crystal structure of ion-substituted Ca-P and ion-substituted Ca-P thin coatings. It is revealed that coating thickness, surface morphology and crystal structure of ion-substituted Ca-P coatings via PVDMS directly affect the biocompatibility and cell responses of such structures. The cell responses determine the osseointegration between the implant and host bone and eventually the success of the implants.

External Fixator-assisted Ulnar Osteotomy: A Novel Technique to Treat Missed Monteggia Fracture in Children

Objective

The treatment of missed Monteggia fracture remains a challenge, despite the various surgical methods described. The purpose of this study was to explore a new surgical technique utilizing external fixator‐assisted ulnar osteotomy and to assess the surgical results in a case series.

Methods

Thirteen patients with missed Monteggia fractures were treated at our institution using this new surgical technique from August 2012 to January 2016. Our series included 11 boys and 2 girls. The left elbow was involved in 6 patients and the right elbow was involved in 7 patients. According to the Bado classification, 10 fractures were classified as Bado type I with anterior radial head dislocation and 3 were classified as Bado type III with anterolateral dislocation. The average age at the time of surgery was 5 years 8 months (range, 2 years 2 months–10 years). The mean trauma‐to‐surgery interval was 12 months (range, 2–36 months). All patients underwent ulnar osteotomy with angulation and lengthening using a temporary external fixator, plate fixation of the osteotomy, and open reduction of the radial head dislocation without annular ligament reconstruction.

Results

The average follow‐up was 27 months (range, 16–44 months). The average operation time was 175 min (range, 140–215 min). The average length of distraction was 0.7 cm (range, 0.5–1.2 cm) and the average angulation was 28° (range, 20°–30°) at the ulnar osteotomy site intraoperatively. The elbow performance score (Kim's) was excellent in 10 cases and good in 3 cases. No neurovascular complications, compartment syndrome or implant breakage occurred. No pain in the distal radioulnar joint or limited range of motion of the wrist occurred in any patient. The radial head remained reduced in all patients with no subluxation or redislocation. However, delayed ulnar union occurred in 3 cases, all of which were successfully treated with plaster cast immobilization within approximately 6 months postoperatively. One patient presented with cubitus valgus postoperatively with a carrying angle of 30°, which was 10° greater than the contralateral carrying angle.

Conclusions

External fixator‐assisted ulnar osteotomy offers substantial flexibility for achieving the optimal positioning of the transected ulna to reduce the radial head prior to the final ulnar osteotomy fixation with a plate, thereby facilitating an effective operative performance. Our procedure is a safe and effective method to treat missed pediatric Monteggia fractures.

A two-phase gradual silver release mechanism from a nanostructured TiAlV surface as a possible antibacterial modification in implants

Titanium biomaterials are widely used in the medical field due to their biocompatibility and excellent corrosion and mechanical resistance. However, these materials have no antibacterial properties. To obtain an antibacterial active surface, a nanostructure of Ti6Al4V alloy was created. This specific nanostructure contained nanotubes and micro-cavities and was used as a substrate for silver anchoring. The electrochemical approach to silver reduction was studied. It is a common approach for silver deposition and in this work, inhomogeneities in the nanostructure were used as a preferential area for silver localisation. The galvanostatic regimen of deposition allowed for a technically quantitative process and the required silver placement. The experimental conditions used enabled testing and silver dissolution rate evaluation within a reasonable time span. Based on the corrosion and analytical results (EDS, XPS and ICP-MS), a two-phase silver release mechanism was confirmed. The openings of the individual nanotubes were filled with silver nanoparticles, whose release was relatively fast. By contrast, the silver anchored inside the cavities allowed the silver to release gradually. Antibacterial efficiency against Staphylococcus aureus and Escherichia coli was successfully demonstrated. Cytotoxicity testing with murine fibroblasts showed cell metabolic activity far above the normative limit of 70%.

Combined use of Kirschner wires and hinged external fixator for capitellar and trochlear fractures: a minimum 24-month follow-up

BACKGROUND

Open reduction and internal fixation is the adequate treatment for capitellar and trochlear fractures. Given the low incidence of this type of fractures, it is difficult to constitute a universally accepted method for fixation. Thus, we hypothesised that combined use of Kirschner wires (K-wires), absorbable rods and sutures for fixation and post-operative hinged external fixator for early rehabilitation exercise can restore elbow joint function well.

METHODS

This retrospective study included 20 patients with a mean age of 48.3 (range 16-76) years. According to the Dubberley classification, fractures were classified on plain radiographs, computed tomography images and intra-operative findings. All patients were evaluated by the range of motion of the elbow and the Broberg-Morrey score.

RESULTS

All fractures had healed without non-union, and the average time was 13.6 (range 8-17) weeks. The mean follow-up was 42.5 (range 24-80) months. The mean flexion was 117.1° (range 90°-135°), and the mean extension was 17.5° (range 0°-45°). The mean pronation was 74.4° (range 45°-85°), and the mean supination was 84.3° (range 60°-90°). The average Broberg-Morrey score was 86.2 (range 68-98) points with 10 excellent, 7 good and 3 fair results.

CONCLUSION

K-wires, absorbable rods and sutures combined with hinged external fixator are feasible for fixation of capitellar and trochlear fractures. However, due to the absence of a control group (such as Herbert screw fixation), comparative studies are still needed to demonstrate the safety and reliability of K-wires for fixation.

A novel patient-specific three-dimensional-printed external template to guide iliosacral screw insertion: a retrospective study

Background

Iliosacral screw fixation is a popular method for the management of posterior pelvic ring fractures or dislocations, providing adequate biomechanical stability. Our aim in this study was to describe the use of a new patient-specific external template to guide the insertion of iliosacral screws and to evaluate the efficacy and safety of this technique compared with the conventional fluoroscopy-guided technique.

Methods

This was a retrospective study of patients with incomplete or complete posterior pelvic ring disruptions who required iliosacral screw fixation. For analysis, patients were divided into two groups: the external template group (37 screws in 22 patients) and the conventional group (28 screws in 18 patients). The operative time per screw, radiation exposure time and the rate of screw perforation (accuracy) were compared between groups. In the external template group, the difference between the actual and planned iliosacral screw position was also compared.

Results

In the conventional group, the average operative time per screw was 39.7 ± 10.6 min, with an average radiation exposure dose of 1904.0 ± 844.5 cGy/cm², with 4 cases of screw perforation. In the external template group, the average operative time per screw was 17.9 ± 4.7 min, with an average radiation exposure dose of 742.8 ± 230.6 cGy/cm² and 1 case of screw perforation. In the template group, the mean deviation distance between the actual and planned screw position was 2.75 ± 1.0 mm at the tip, 1.83 ± 0.67 mm in the nerve root tunnel zone and 1.52 ± 0.48 mm at the entry point, with a mean deviation angle of 1.73 ± 0.80°.

Conclusions

The external template provides an accurate and safe navigation tool for percutaneous iliosacral screw insertion that could decrease the operative time and radiation exposure.

Novel Use of Active Leptospermum Honey for Ringed Fixator Pin Site Care in Diabetic Charcot Deformity Patients

INTRODUCTION

Open reduction with external fixation (OREF) utilizing fine wire ringed fixators for correction of Charcot deformity has gained popularity over the past decade. Pin site infections are a well-documented complication of external fixation as well as a driver of escalating health care costs. We aimed to demonstrate the safety and efficacy of a novel method of pin site care utilizing active Leptospermum honey-impregnated dressings (MediHoney) in diabetic patients undergoing deformity correction with OREF.

METHODS

Twenty-one diabetic patients with Charcot deformities of the lower extremity were prospectively enrolled and followed for pin site complications following OREF for deformity correction. Active Leptospermum honey dressings were applied at metal-cutaneous interfaces at the end of the OREF procedure and replaced weekly for a total of 8 weeks. Patients were monitored for pin site infections from the time of surgery until external fixator removal. Sixteen consecutive patients receiving standard OREF for Charcot deformities were evaluated retrospectively to serve as a control group.

RESULTS

Of the 21 enrolled patients, 19 underwent OREF and followed up throughout the study period. Treated patients had a mean age of 58.5 years and mean body mass index measuring 33.3 kg/m² as documented prior to surgery. The 15 patients with hemoglobin A1c labs drawn in the 3 months preceding surgery averaged 7.5. Fixators were removed at an average of 12.1 weeks after adequate bony healing. Of the 244 pin sites in 19 patients, 3 pin sites (1.2% of pins) in 2 patients (10.5% of patients) showed evidence of superficial infection. All infections resolved with oral antibiotics. Infection rates were significantly reduced when compared to the standard care control group.

CONCLUSIONS

Pilot data in a prospectively collected case series demonstrate safety and efficacy of active Leptospermum honey-impregnated dressings when used for fine wire ringed fixator pin site care in diabetic Charcot deformity patients. Further investigation in the form of a prospective randomized controlled study is warranted to demonstrate the potential value of this novel intervention.

LEVELS OF EVIDENCE

Level IV.

Electrophoretic Deposition of Gentamicin-Loaded Silk Fibroin Coatings on 3D-Printed Porous Cobalt-Chromium-Molybdenum Bone Substitutes to Prevent Orthopedic Implant Infections

In addition to customizing shapes of metal bone substitutes for patients, the 3D printing technique can reduce the modulus of the substitutes through the design and manufacture of interconnected porous structures, achieving the modulus match between substitute and surrounding bone to improve implant longevity. However, the porous bone substitutes take more risks of postoperative infection due to its much larger surface area compared with the traditional casting solid bone substitute. Here, we prepared of gentamicin-loaded silk fibroin coatings on 3D-printed porous cobalt-chromium-molybdenum (CoCrMo) bone substitutes via electrophoretic deposition technique. Through optimization, relatively intact, continuous, homogeneous, and conformal coatings with a thickness of 2.30 ± 0.58 μm were deposited around the struts with few pore blocked. The porous metal structures exhibited no loss in mechanical properties after the anode galvanic corrosion in EPD process. The initial osteoblastic response on coatings was better than that on metal surface, including cell spreading, proliferation and cytotoxicity. Antibacterial efficacy experiments showed that the coatings had an antibacterial effect on both adherent and planktonic bacteria within 1 week. These results suggested that the beneficial properties of anode electrophoretic deposited silk fibroin coatings could be exploited to improve the biological functionality of porous structures made of medical metals.

[Application of Orthofix unilateral external fixator in the treatment of musculoskeletal tumors]

Objective

To investigate the surgical characteristics and preliminary effectiveness of Orthofix unilateral external fixator in the treatment of musculoskeletal tumors.

Methods

Twenty-two patients received Orthofix unilateral external fixator treatment for bone defect after tumor excision or complications after limb salvage surgery between June 2011 and March 2016. There were 11 males and 11 females with a median age of 23.5 years (range, 4-57 years). The bone defect or limb length discrepancy after tumor resection was at proximal femur in 6 cases, distal femur in 8 cases, diaphysis of femur in 3 cases, proximal tibia in 2 cases, and diaphysis of tibia in 3 cases. The external fixation was used for temporary fixation after reconstruction of bone defect in 10 cases [the length of bone defect was 6-19 cm (mean, 12.3 cm); using vascularized fibular graft in 2 cases, allograft bone and free fibular graft in 2 cases, allograft bone and autogenous bone graft in 5 cases, allograft bone reconstruction in 1 case]; bone distraction lengthening for limb length discrepancy in 5 cases [the length of shortening was 6.5-8.5 cm (mean, 7.5 cm)]; temporary fixation after open biopsy in 3 cases; bone transportation over locking plate in 1 case (the length of bone defect was 7.5 cm); fixation for preoperatively pathology fracture in 1 case; and joint distraction for dislocation after tumor ablation in 2 cases.

Results

All the patients were followed up 12-72 months (mean, 36 months). In 10 patients with bone defect reconstruction, the wearing external fixator time was 3-8 months (mean, 4.8 months); all got bone union with the healing time of 3-16 months (mean, 6.4 months); the Musculoskeletal Tumor Society 93 (MSTS 93) score was 73.3-93.3 (mean, 87.2); and no complication occurred during wearing external fixator. In 5 patients with bone distraction lengthening for limb length discrepancy, the wearing external fixator time was 7-15 months; 2 patients had axial deviation during distraction and2 had greenstick fracture after apparatus removal; pin site infection was observed in 2 cases with grade 1 and 1 case with grade 2 according to Checketts-Otterburn classification system; the MSTS 93 score was 80.0-96.7 (mean, 89.2). The remaining patients had no complications, the knee and ankle joint movement was normal.

Conclusion

Orthofix unilateral external fixator can be used in fixation for complex bone defect after tumor resection and to correct limb length discrepancy after limb salvage surgery.

Bilateral Ankle Fusion in Leak Syndrome Induced Deformity: A Case Report

Introduction:

Systemic capillary leak syndrome (SCLS) is a rare condition of unknown etiology defined by sudden episode of hypotension, high hematocrit, and low serum protein concentration due to capillary hyperpermeability. Several treatments have been published for this pathology and eventual compartment syndrome but not for the disabling consequences. This clinical case highlights the negative orthopedic consequences of a severe systemic attack and reports a subsequent deformity treatment option that resulted in the patient quality of life improvement. To our knowledge, orthopedic surgery for SCLS induced foot and ankle deformity is presented for the first time.

Case Report:

A 40-year-old Caucasian female patient was referred to our institution for bilateral foot and ankle deformity after compartment syndrome during SCLS attack. She presented a bilateral rigid equino-cavo-varus-adductus deformity causing walk impairment. Bilateral ankle fusion by retrograde nailing was performed in a two-staged procedure. Rigid claw toes were also surgically addressed in an additional procedure. Radiologically, apparent ankle fusion occurred at 3 months post-operative in both sides. Deformity correction allowed the patient to regain walking capacity. A right ankle tibiotalar failed arthrodesis was noticed at 24 months post-operative. Prophylactic human immunoglobulin therapy was initiated after the last surgery with no recurrent attack registered during the 38 months follow-up period.

Conclusion:

Bilateral ankle fusion improved this patient quality of life by restituting walking capacity and lowering the probability of lower limb deformity related ulcers and infections. Major and minor complications are also discussed. This report contributes to the global knowledge about this syndrome and elicits the importance of the induced deformities surgical correction.

Biotransformation of Silver Released from Nanoparticle Coated Titanium Implants Revealed in Regenerating Bone

Antimicrobial silver nanoparticle coatings have attracted interest for reducing prosthetic joint infection. However, few studies report in vivo investigations of the biotransformation of silver nanoparticles within the regenerating tissue and its impact on bone formation. We present a longitudinal investigation of the osseointegration of silver nanoparticle-coated additive manufactured titanium implants in rat tibial defects. Correlative imaging at different time points using nanoscale secondary ion mass spectrometry, transmission electron microscopy (TEM), histomorphometry, and 3D X-ray microcomputed tomography provided quantitative insight from the nano- to macroscales. The quality and quantity of newly formed bone is comparable between the uncoated and silver coated implants. The newly formed bone demonstrates a trabecular morphology with bone being located at the implant surface, and at a distance, at two weeks. Nanoscale elemental mapping of the bone-implant interface showed that silver was present primarily in the osseous tissue and colocalized with sulfur. TEM revealed silver sulfide nanoparticles in the newly regenerated bone, presenting strong evidence that the previously in vitro observed biotransformation of silver to silver sulfide occurs in vivo.

Novel Antibacterial Coating on Orthopedic Wires To Eliminate Pin Tract Infections

Novel approaches to the prevention of microbial infections after the insertion of orthopedic external fixators are in great demand because of the extremely high incidence rates of such infections, which can reach up to 100% with longer implant residence times. Monolaurin is an antimicrobial agent with a known safety record that is broadly used in the food and cosmetic industries; however, its use in antimicrobial coatings of medical devices has not been studied in much detail. Here, we report the use of monolaurin as an antibacterial coating on external fixators for the first time. Monolaurin-coated Kirschner wires (K-wires) showed excellent antibacterial properties against three different bacterial strains, i.e., methicillin-sensitive Staphylococcus aureus (MSSA), methicillin-resistant Staphylococcus aureus (MRSA), and Staphylococcus epidermidis Approximately 6.0-log reductions of both planktonic and adherent bacteria were achieved using monolaurin-coated K-wires, but monolaurin-coated K-wires did not show any observable cytotoxicity with mouse osteoblast cell cultures. Overall, monolaurin-coated K-wires could be promising as potent antimicrobial materials for orthopedic surgery.

Delayed methicillin-resistant Staphylococcus aureus-induced osteomyelitis of the tibia after pin tract infection: two case reports

BACKGROUND

Pin tract infection is a common complication of external fixation. It usually heals after treatment with debridement, antibiotics, and/or pin removal, only rarely developing into delayed osteomyelitis. We treated two patients with delayed methicillin-resistant Staphylococcus aureus-induced osteomyelitis of the tibia following pin tract infection.

CASE PRESENTATION

One patient, a diabetic 60-year-old Japanese man, underwent definitive external fixation using an Ilizarov fixator for postoperative osteomyelitis of an open fracture of his left ankle. One year after removing the external fixator, he developed methicillin-resistant Staphylococcus aureus-induced osteomyelitis of the tibial pin site. He underwent surgical debridement four times. No recurrence was seen 2 years 8 months after the last debridement. Another patient, a healthy 38-year-old Japanese man, underwent bilateral temporary external fixation for a right ankle open fracture and a comminuted fracture of the left tibial plateau. Three months after removal of the external fixator, he was diagnosed with methicillin-resistant Staphylococcus aureus-induced osteomyelitis of the bilateral tibial pin sites. He underwent surgical debridement three times, but the infection of his right tibia persisted. Finally, a gastrocnemius muscle flap was placed. No recurrence was seen 2 years after this last surgery.

CONCLUSIONS

Pin tract infection should not be considered a minor complication because osteomyelitis may develop, requiring treatment that is more aggressive than curettage of the pin tract. A gastrocnemius flap is a useful treatment option for refractory osteomyelitis because flap harvest causes less functional disturbance and is a relatively easy surgical technique.

Knee joint distraction compared with high tibial osteotomy: a randomized controlled trial

PURPOSE

Both, knee joint distraction as a relatively new approach and valgus-producing opening-wedge high tibial osteotomy (HTO), are knee-preserving treatments for knee osteoarthritis (OA). The efficacy of knee joint distraction compared to HTO has not been reported.

METHODS

Sixty-nine patients with medial knee joint OA with a varus axis deviation of <10° were randomized to either knee joint distraction (n = 23) or HTO (n = 46). Questionnaires were assessed at baseline and 3, 6, and 12 months. Joint space width (JSW) as a surrogate measure for cartilage thickness was determined on standardized semi-flexed radiographs at baseline and 1-year follow-up.

RESULTS

All patient-reported outcome measures (PROMS) improved significantly over 1 year (at 1 year p < 0.02) in both groups. At 1 year, the HTO group showed slightly greater improvement in 4 of the 16 PROMS (p < 0.05). The minimum medial compartment JSW increased 0.8 ± 1.0 mm in the knee joint distraction group (p = 0.001) and 0.4 ± 0.5 mm in the HTO group (p < 0.001), with minimum JSW improvement in favour of knee joint distraction (p = 0.05). The lateral compartment showed a small increase in the knee joint distraction group and a small decrease in the HTO group, leading to a significant increase in mean JSW for knee joint distraction only (p < 0.02).

CONCLUSION

Cartilaginous repair activity, as indicated by JSW, and clinical outcome improvement occurred with both, knee joint distraction and HTO. These findings suggest that knee joint distraction may be an alternative therapy for medial compartmental OA with a limited mechanical leg malalignment.

LEVEL OF EVIDENCE

Randomized controlled trial, Level I.

From prevention of pin-tract infection to treatment of osteomyelitis during paediatric external fixation

Pin-tract infection (PTI) is the most commonly expected problem, or even an almost inevitable complication, when using external fixation. Left unteated, PTI will progress unavoidably, lead to mechanical pin loosening, and ultimately cause instability of the external fixator pin-bone construct. Thus, PTI remains a clinical challenge, specifically in cases of limb lengthening or deformity correction. Standardised pin site protocols which encompass an understanding of external fixator biomechanics and meticulous surgical technique during pin and wire insertion, postoperative pin site care and pin removal could limit the incidence of major infections and treatment failures. Here we discuss concepts regarding the epidemiology, physiopathology and microbiology of PTI in paediatric populations, as well as the clinical presentations, diagnosis, classification and treatment of these infections.