Free peroneal artery perforator flap for reconstruction of traumatic limb soft tissue defects: A retrospective case series study.

BACKGROUND: The free peroneal artery perforator (FPAP) flap is used for soft tissue defects after burns and trauma. However, the use of FPAP flaps to repair limb soft tissue defects for immediate reconstruction was rarely reported previously. Therefore, the purpose of this report is to evaluate free peroneal artery perforator flap to reconstruct traumatic limb soft tissue defects for immediate reconstruction. PATIENTS AND METHODS: A total of 25 cases of limb soft tissue defects undergoing immediate reconstruction of FPAP flap transfer were retrospectively evaluated from January 2019 to June 2019 in our institute. The locations of defects included the palm (10 cases), finger (5 cases), foot (7 cases), ankle (2 cases) and wrist (1 case). The sizes of defect varied from 3 × 2 cm to 15 × 7 cm (54.1 cm2 in average). Flaps were harvested based on the peroneal perforator vessels, initially marked using hand-held Doppler. RESULTS: Average size of harvested flap was 9.7 × 6.2 cm (ranging from 3.5 × 2 cm to 16 × 8 cm). All perforators were harvested from the peroneal artery and the arterial diameter ranged from 0.8 to 1.7 mm. The average pedicle length was 3.04 cm (range, 1.85-4.75 cm). Five vascular thrombosis were found including three cases of arterial thrombosis and two cases of venous thrombosis which were successfully salvaged by re-operation and vein graft. Satisfying functional outcome and acceptable appearance were achieved at 6 months or longer after surgery (range, 6-15 months, 12 months in average). All flaps survived at the end-point. CONCLUSIONS: The FPAP flap is a reliable and thin fasciocutaneous flap, which can be used for repairing limb soft tissue defects. The FPAP flap can be used for covering defects with various appearances, locations, and sizes.

Does Preoperative Glycemic Control Restore Immune Defense Against Implant-related Infection in Mice With Diabetes?

BACKGROUND: The presence of Type II diabetes is a well-established risk factor for bone and joint infection, especially in patients with poor glycemic control. However, few studies have investigated the effect of the duration of preoperative glycemic intervention. For patients with poor glycemic control, the effect of the duration of preoperative glycemic intervention remains unknown. Many glycemic biomarkers including hemoglobin A1c (HbA1c), fructosamine, and 1,5-anhydroglucitol have different response rates to glycemic change. It is unclear which biomarker is more closely related to the decrease in infection proportion after preoperative glycemic intervention. QUESTIONS/PURPOSES: (1) Is there an effect of the duration of preoperative insulin therapy in mice with diabetes receiving an experimental intra-articular implant? (2) Of the three commonly used biomolecules for monitoring blood glucose levels (HbA1c, fructosamine, and 1,5-anhydroglucitol), is one more closely related to decrease in infection proportion after presurgical insulin therapy? METHODS: With a well-established protocol, Type II diabetes was modeled in female 10-week-old C57BL/6 mice by maintaining them on a high-fat diet (60% fat) for 8 months; control mice without diabetes received a normal low-fat diet (10% fat). Mice with Type II diabetes were randomized into groups to receive preoperative glycemic intervention with insulin for 0, 1, 3, 5, 7, 14, or 28 days, and investigators were blinded to the randomization. Mice with and without diabetes then received a surgically inserted wire into the femoral canal in a retrograde fashion and received a local or systemic challenge with Staphylococcus aureus or Escherichia coli (n = 20 for each bacteria challenge [systemic or local]/timepoint). The proportion of culture-positive joint samples was calculated. An additional 10 mice with Type II diabetes were treated with insulin for 28 days and the HbA1c, fructosamine, and 1,5-anhydroglucitol levels were consecutively monitored. Fisher exact tests and nonparametric Wilcoxon rank sum tests were used to analyze the different between different groups, with p < 0.05 taken as significant. RESULTS: When insulin therapy was administered, the proportion of bone and joint infections decreased in mice with Type II diabetes, reaching asymptotic levels after 3 days of treatment for the systemic (S. aureus: 7 of 20 mice with diabetes on 3-day therapy, p < 0.001; 8 of 20 on 5-day, p = 0.002; 10 of 20 on 7-day, p = 0.01; 9 of 20 on 14-day, p = 0.006; and 8 of 20 on 28-day, p = 0.002 versus 18 of 20 in the no insulin therapy group; E. coli: 6 of 20 on 3-day therapy, p = 0.004; 7 of 20 on 5-day, p = 0.01; 7 of 20 on 7-day, p = 0.01; 6 of 20 on 14-day, p = 0.004; and 7 of 20 on 28-day, p = 0.01 versus 16 of 20 in the no insulin therapy group) or local bacterial challenge (S. aureus: 11 of 20 on 3-day therapy, p = 0.001; 12 of 20 on 5-day, p = 0.003; 10 of 20 on 7-day, p < 0.001; 12 of 20 on 14-day, p = 0.003; and 13 of 20 on 28-day, p = 0.008 versus 20 of 20 in the no insulin therapy group; E. coli: 10 of 20 on 3-day therapy, p = 0.003; 10 of 20 on 5-day, p = 0.003; 9 of 20 on 7-day, p = 0.001; 11 of 20 on 14-day, p = 0.008; and 10 of 20 on 28-day, p = 0.003 versus 19 of 20 in no insulin therapy group). Even after 28 days of insulin therapy, the proportion of bone and joint infections was still higher (statistically insignificant with large absolute difference, except for one instance) in mice with diabetes than in control mice without diabetes after systemic (S. aureus: 8 of 10 mice with diabetes on 28-day therapy versus 4 of 20 mice without diabetes, p = 0.30; E. coli: 7 of 20 on 28-day therapy versus 1 of 20 mice without diabetes, p = 0.04) or local challenge (S. aureus: 13 of 20 mice on 28-day therapy versus 8 of 20 mice without diabetes, p = 0.21; E. coli: 10 of 20 on 28-day therapy versus 5 of 20 mice without diabetes, p = 0.19). HbA1c and fructosamine levels were lagging indicators of the decrease in infection proportion after insulin treatment. In contrast, the 1,5-anhydroglucitol level increased quickly (reflecting lower blood glucose levels) in response to short-term glycemic control. Moreover, the time required for changes in 1,5-anhydroglucitol levels to be detected was no more than 3 days (3 days insulin therapy 1.86 ± 0.20 [95% CI -1.27 to -0.45]; p˂0.001 versus no insulin therapy 1.00 ± 0.11). CONCLUSION: In a model of mice with Type II diabetes, prolonged preoperative glycemic intervention did not further reduce the proportion of bone and joint infections compared with that achieved with short-term intervention of 3 days. CLINICAL RELEVANCE: Compared with HbA1c and fructosamine, 1,5-anhydroglucitol might be a better indicator for risk stratification and guiding the timing for elective surgery. Comparative study of these three biomarkers based on patient samples is warranted to further confirm this conclusion.

A retrospective cohort study on prevalence of postoperative complications in comminuted patellar fractures: comparisons among stabilized with Cannulated-Screw, Kirschner-Wire, or Ring-Pin Tension Bands.

BACKGROUND: Displaced patellar fractures are commonly treated with open reduction and fixation with several different types of tension-band (TB) constructs. The main objective of this study was to compare the prevalence of postoperative complications after surgical stabilization of comminuted patellar fractures with either a modified Kirschner-wire tension band (MKTB), a cannulated-screw tension band (CSTB), or a ring-pin tension band (RPTB). METHODS: We conducted a retrospective and consecutive cohort study of comminuted patellar fractures (n = 334) stabilized using a TB construct. Postoperative premature loss of reduction, infection, and skin breakdown were compared according to the type of TB constructs received (MKTB, CSTB, or RPTB). The rate of implant removal due to symptomatic hardware was also evaluated. RESULTS: Fixation failure rate was significantly different among the groups (P = 0.013), with failure rates of 4.7% observed in the MKTB group,14.5% in the CSTB group, and 4.9% in the RPTB group. Skin breakdown and infection were not significantly different among the groups (Ps > 0.05). Due to symptomatic hardware, 40.5% of the patients in the MKTB group, 22.9% in the CSTB group, and 24.3% in the RPTB group underwent implant removal (P = 0.004). After adjusting for age, gender, comorbidities, number of supplementary screws/K-wires, and use of cerclage cables, multivariate regression analysis revealed that CSTB contributed to a 2.08-times greater risk of fixation failure compared to RPTB, while MKTB and RPTB were similar in risk of failure. In addition, it was found that patients who underwent MKTB fixation were more than twice as likely to undergo implant removal for symptomatic hardware compared with RPTB (odds ratio = 2.11, 95% CI = 1.20 to 3.72; P = 0.010). CONCLUSIONS: RPTB have advantage over MKTB and CSTB fixation in terms of symptomatic hardware and premature failure, respectively. LEVEL OF EVIDENCE: Therapeutic Level III.

Changes in Temporal and Spatial Patterns of Intrinsic Brain Activity and Functional Connectivity in Upper-Limb Amputees: An fMRI Study.

Background: Amputation in adults is a serious procedure or traumatic outcome, one that leads to a possible "remapping" of limb representations (somatotopy) in the motor and sensory cortex. The temporal and spatial extent underlying reorganization of somatotopy is unclear. The aim of this study was to better understand how local and global structural plasticity in sensory-motor cortical networks changes temporally and spatially after upper-limb amputation. Methods: We studied 8 healthy nonamputee control subjects and 16 complete upper-limb amputees. Resting-state MRI (rs-fMRI) was used to measure local and large-scale relative differences (compared to controls) in both the amplitude of low-frequency fluctuations (ALFF) and degree of centrality (DC) at 2 months, 6 months, and 12 months after traumatic amputation. Results: In amputees, rs-fMRI scans revealed differences in spatial patterns of ALFF and DC among brain regions over time. Significant relative increases in ALFF and DC were detected not only in the sensory and motor cortex but also in related cortical regions believed to be involved in cognition and motor planning. We observed changes in the magnitude of ALFFs in the pre- and postcentral gyrus and primary sensory cortex, as well as in the anterior cingulate, parahippocampal gyrus, and hippocampus, 2 months after the amputation. The regional distribution of increases/decreases in ALFFs and DC documented at 2-month postamputation was very different from those at 6 and 12-month postamputation. Conclusion: Local and wide-spread changes in ALFFs in the sensorimotor cortex and cognitive-related brain regions after upper-limb amputation may imply dysfunction not only in sensory and motor function but also in areas responsible for sensorimotor integration and motor planning. These results suggest that cortical reorganization after upper extremity deafferentation is temporally and spatially more complicated than previously appreciated, affecting DC in widespread regions.

Does Training Innate Immunity Confer Broad-spectrum Protection Against Bone and Joint Infection in a Mouse Model?

BACKGROUND: The innate immune system can recall previous immunologic challenges and thus respond more effectively to subsequent unrelated challenges, a phenomenon called trained immunity. Training the innate immune system before surgery might be a potential option to prevent bone and joint infection. QUESTIONS/PURPOSES: (1) Does the training process cause adverse effects such as fever or organ injury? (2) Does training the innate immune system confer broad-spectrum protection against bone and joint infection in a mouse model? (3) Does trained immunity remain effective for up to 8 weeks in this mouse model? METHODS: After randomization and group information blinding, we trained the innate immune system of C57BL/6 mice (n = 20 for each group) by intravenously injecting them with either 0.1 mg of zymosan (a toll-like receptor 2 agonist), 0.1 mg of lipopolysaccharide (a toll-like receptor 4 agonist), or normal saline (control). For assessing the host response and possible organ injury after training and infection challenge, we monitored rectal temperature, collected blood to determine leukocyte counts, and performed biochemical and proinflammatory cytokine analyses. After 2 weeks, we then assessed whether trained immunity could prevent infections in an intraarticular implant model subjected to a local or systemic challenge with a broad spectrum of bacterial species (Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, Streptococcus pyogenes, or Pseudomonas aeruginosa) in terms of culture-positive rate and colony counts. The proportion of culture-positive joint samples from trained and control groups were compared after 4 weeks. Finally, we increased the interval between training and bacterial challenge up to 8 weeks to assess the durability of training efficacies. RESULTS: Training with zymosan and lipopolysaccharide caused mild and transient stress in host animals in terms of elevated rectal temperature and higher blood urea nitrogen, creatinine, alanine aminotransferase, and aspartate aminotransferase levels. Trained mice had fewer culture-positive joint samples after local inoculation with S. aureus (control: 100% [20 of 20]; zymosan: 55% [11 of 20], relative risk 0.55 [95% CI 0.37 to 0.82]; p = 0.001; lipopolysaccharide: 60% [12 of 20], RR 0.60 [95% CI 0.42 to 0.86]; p = 0.003) and systemic challenge with S. aureus (control: 70% [14 of 20]; zymosan: 15% [3 of 20], RR 0.21 [95% CI 0.07 to 0.63]; p = 0.001; lipopolysaccharide: 15% [3 of 20], RR 0.21 [95% CI 0.07 to 0.63]; p = 0.001) than controls. We observed similar patterns of enhanced protection against local and systemic challenge of E. coli, E. faecalis, S. pyogenes, and P. aeruginosa. Zymosan-trained mice were more effectively protected against both local (control: 20 of 20 [100%], zymosan: 14 of 20 [70%], RR 0.70 [95% CI 0.53 to 0.93]; p = 0.02) and systemic (control: 70% [14 of 20]; zymosan: 30% [6 of 20], RR 0.43 [95% CI 0.21 to 0.89]; p = 0.03) challenge with S. aureus for up to 8 weeks than controls. CONCLUSIONS: Trained immunity confers mild stress and broad-spectrum protection against bone and joint infection in a mouse model. The protection conferred by immunity training lasted up to 8 weeks in this mouse model. The results of the current research support further study of this presurgical strategy to mitigate bone and joint infection in other large animal models. CLINICAL RELEVANCE: If large animal models substantiate the efficacy and safety of presurgical immunity training-based strategies, clinical trials would be then warranted to translate this strategy into clinical practice.

Is EDTA Irrigation Effective in Reducing Bacterial Infection in a Rat Model of Contaminated Intra-articular Knee Implants?

BACKGROUND: To mitigate the possibility of infection after arthroplasty, intraoperative irrigation is essential to remove contaminating bacteria. Previous studies have demonstrated that irrigation with an EDTA solution before wound closure is superior to irrigation with normal saline in removing contaminating bacteria in a rat model of open fractures. However, the effectiveness of an EDTA solution in a model with a contaminated intra-articular implant remains unclear. QUESTIONS/PURPOSES: (1) Does irrigation with an EDTA solution decrease the proportion of culture-positive joints compared with normal saline, benzalkonium chloride, and povidone iodine? (2) Is an EDTA solution toxic to cells resident in joints including chondrocytes, osteoblasts, and synovial fibroblasts? (3) Does irrigation with an EDTA solution have adverse effects including arthrofibrosis and hypocalcemia? METHODS: We first established a model of contaminated intra-articular implants. Female Sprague-Dawley rats (n = 30 for each treatment group) underwent knee arthrotomy and implantation of a femoral intramedullary wire with 1 mm of intra-articular communication. To simulate bacterial contamination, the inserted wire was inoculated with either Staphylococcus aureus or Escherichia coli. After 1 hour, the wound and implant were irrigated with normal saline, benzalkonium chloride, povidone iodine, or an EDTA solution (1 mM). The animals were euthanized 1 week later, and the distal femur, knee capsule, and implanted wire were harvested for bacterial culture using standard techniques. In this study, we used a well-established animal model of an intra-articular implant and inoculated the implant to simulate the clinical setting of intraoperative contamination. The proportion of culture-positive joints in normal saline, benzalkonium chloride, povidone-iodine, and EDTA groups were compared. The viable cell numbers (chondrocytes, osteoblasts, and synovial fibroblasts) were counted and compared after treatment with either solution. Measurement of blood calcium level and histological examination of the joint were performed to rule out hypocalcemia and arthrofibrosis after EDTA irrigation. RESULTS: With S. aureus inoculation, EDTA irrigation resulted in fewer culture-positive joints than normal saline (37% [11 of 30] versus 70% [21 of 30]; p = 0.019), benzalkonium chloride (83% [25 of 30]; p < 0.001), and povidone iodine (83% [25 of 30]; p < 0.001) irrigation. Likewise, infection rates for implant inoculation with E. coli were also lower in the EDTA irrigation group (13% [four of 30]) than in the normal saline (60% [18 of 30]; p < 0.001), benzalkonium chloride (77% [23 of 30]; p < 0.001), and povidone iodine (80% [24 of 30]; p < 0.001) groups. Between normal saline control and EDTA, there were no differences in cell viability in chondrocytes (normal saline: 98% ± 18%; EDTA: 105% ± 18%; p = 0.127), osteoblasts (normal saline: 102 ± 19%, EDTA: 103 ± 14%; p = 0.835), and synovial fibroblasts (normal saline: 101% ± 21%, EDTA: 110% ± 13%; p = 0.073). EDTA irrigation did not result in hypocalcemia (before irrigation: 2.21 ± 0.32 mmol/L, after irrigation: 2.23 ± 0.34 mmol/L; p = 0.822); and we observed no arthrofibrosis in 30 histologic samples. CONCLUSIONS: In a rat model of a bacteria-contaminated intra-articular implants, intraoperative irrigation with 1 mmol/L of an EDTA solution was superior to normal saline, 0.03% benzalkonium chloride, and 0.3% povidone iodine in preventing surgical-site infection and caused no adverse effects including death of resident cells, arthrofibrosis, and hypocalcemia. Future studies should seek to replicate our findings in other animal models, perhaps such as dog and goat. CLINICAL RELEVANCE: If other animal models substantiate the efficacy and safety of the EDTA solution, clinical trials would be warranted to determine whether the use of an EDTA irrigation solution might reduce the risk of periprosthetic joint infections in patients compared with traditional irrigation solutions.

Is NS-EDTA Effective in Clearing Bacteria From Infected Wounds in a Rat Model?

BACKGROUND: Irrigation is one of the key procedures in open fracture management to eliminate pathogens and prevent infection. Metal ion deprivation could inhibit bacterial adhesins and weaken adhesion to the host tissue. EDTA in solution can competitively bind to a metal ion and thus might be able to inhibit bacterial adhesins. QUESTIONS/PURPOSES: (1) Is normal saline-EDTA toxic to fibroblasts and endothelial cells? (2) In a contaminated wound rat model, does irrigation with normal saline-EDTA solution decrease the risk of positive bacterial cultures and infection when compared with normal saline and soap solutions? (3) In an infected wound rat model, are fewer surgical débridements and irrigations with normal saline-EDTA solution required to obtain culture-free wounds when compared with normal saline and soap controls? METHODS: Normal saline-EDTA solution refers to 1 mmol/L EDTA dissolved in normal saline (pH adjusted to 7.4). Normal saline and soap solutions acted as controls. The toxicity of these solutions to fibroblasts and endothelial cells was assessed in vitro by Annexin V/propidium iodide staining and flow cytometer counting (a well-established method to quantitatively measure the number of dead cells). We established contaminated and infected wound models (bone-exposed or not) with either Staphylococcus aureus or Escherichia coli in rats to investigate the efficacy of normal saline-EDTA solution (n = 30 for the contaminated model and n = 50 for the infected model). For contaminated wounds, the proportion of positive bacterial cultures and infections was compared after irrigation and débridement among the three groups. For infected wounds, we performed irrigation and débridement every 48 hours until the cultures were negative and compared the number of débridements required to achieve a negative culture with survival analysis. RESULTS: Normal saline-EDTA showed no additional toxicity to fibroblasts and endothelial cells when compared with normal saline (normal saline [97%] versus EDTA [98%] on fibroblasts, p = 0.654; normal saline [97%] versus EDTA [98%] on endothelial cells, p = 0.711). When bone was exposed in the contaminated models, EDTA irrigation resulted in fewer positive bacterial cultures with S aureus (EDTA: 23%, normal saline: 67%, soap: 40%, p = 0.003) and with E coli (EDTA: 27%, normal saline: 57%, soap: 30%, p = 0.032); however, infection risk was only lower with EDTA irrigation (S aureus with EDTA: 10%, normal saline: 33%, soap: 37%, p = 0.039; E coli with EDTA: 3%, normal saline: 27%, soap: 23%, p = 0.038). In the infected wound model, EDTA irrigation resulted in earlier culture-negative wounds (fewer surgical sessions) compared with normal saline and soap solutions (nonbone-exposed wounds infected by S aureus: p = 0.003, infected by E coli: p = 0.001; bone-exposed wounds infected by S aureus: p = 0.012, infected by E coli: p = 0.022). CONCLUSIONS: After in vitro assessment of toxicity and in vivo evaluation of efficacy, we concluded that normal saline-EDTA is superior to normal saline and soap solution in our laboratory models. CLINICAL RELEVANCE: The use of normal-saline EDTA as an irrigation solution may reduce the infection rate of wounds. Future studies in large animals and humans might prove our observation in rat models that normal saline-EDTA has an advantage over normal saline as an irrigation solution.

Circadian clock gene expression regulates cancer cell growth through glutaminase.

Glutamine is an essential amino acid for malignant tumor cells. Glutaminase that metabolizes glutamine reaches a maximum expression in tumors immediately before the maximum proliferation rate. Tumor cells grow at different rates during the day. We postulated that the activity of glutaminase in tumor cells is subject to the regulation of circadian clock gene. We measured glutaminase by western blot analysis and circadian clock gene expression by real-time polymerase chain reaction in the liver and tumor cells at six equispaced time points of the day in individual mice of a 12/12 h light/dark schedule. The results showed that the tumor-bearing mice, under normal diurnal conditions, are circadianly entrained, as reflected by the normal host locomotor activity rhythms and rhythmic liver clock gene expression. The tumors within these mice are also circadianly organized, as reflected by circadian clock gene (Bmal1) expression. What is most remarkable is that kidney-type glutaminase also showed circadian rhythms in the same pattern with tumor circadian clock gene expression in liver cancer xenograft model, indicating that conditionally inhibiting glutaminase activity may provide a new target for cancer therapy.

Anterior transposition and positioning via helix sling method in cubital tunnel syndrome: An open-label, retrospective trial of maximum 5-year follow-up.

Background: Ulnar nerve transposition is used for cubital tunnel syndrome (CuTS) with nerve instability. The aim is to report a modified technique for ulnar nerve transposition using medial intermuscular septum and Osborne's ligament as a double-strand helix sling to recreate a sliding channel for the ulnar nerve and the functional outcomes at follow-ups. Methods: Twenty-five patients with persistent CuTS underwent nerve release and subcutaneous transposition from January 2017 to January 2022 in our institute. Among them, 9 patients were excluded due to incomplete medical records, lack of follow-up history, or bilateral limb numbness. The medial intermuscular septum with one end attached was excised to rebuild a tension-free double-strand helix sling by anchoring at the residue of Osborne's ligament. The modified Mc-Gowan classification was applied to evaluate the disease severity preoperatively. The quick disability of arm and shoulder and hand (quickDASH) questionnaire and visual analogue scale (VAS) scores were used to evaluate pre- and postoperative symptoms. Ultrasound imaging was utilized for nerve structure evaluation before surgery and at follow-ups. Results: Sixteen out of twenty-five patients received follow-ups postoperatively (ranging from 9 to 69 months, 36 months in average). No findings indicated subluxation of ulnar nerve or recompression by ultrasound imaging examination. According to quickDASH and VAS scores and physical examination, 14 out of 16 patients showed postoperative improvement in symptoms and function at final follow-ups. Interpretation: In this modified technique, the medial intermuscular septum and Osborne's ligament can create tension-free helix sling for stable and smooth sliding and preventing subluxation after nerve transposition, which is highly effective and safe for CuTS treatment.

Efficacy of EDTA-NS irrigation in eradicating Staphylococcus aureus biofilm-associated infection.

Aims: To investigate the efficacy of ethylenediaminetetraacetic acid-normal saline (EDTA-NS) in dispersing biofilms and reducing bacterial infections. Methods: EDTA-NS solutions were irrigated at different durations (1, 5, 10, and 30 minutes) and concentrations (1, 2, 5, 10, and 50 mM) to disrupt Staphylococcus aureus biofilms on Matrigel-coated glass and two materials widely used in orthopaedic implants (Ti-6Al-4V and highly cross-linked polyethylene (HXLPE)). To assess the efficacy of biofilm dispersion, crystal violet staining biofilm assay and colony counting after sonification and culturing were performed. The results were further confirmed and visualized by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). We then investigated the efficacies of EDTA-NS irrigation in vivo in rat and pig models of biofilm-associated infection. Results: When 10 mM or higher EDTA-NS concentrations were used for ten minutes, over 99% of S. aureus biofilm formed on all three types of materials was eradicated in terms of absorbance measured at 595 nm and colony-forming units (CFUs) after culturing. Consistently, SEM and CSLM scanning demonstrated that less adherence of S. aureus could be observed on all three types of materials after 10 mM EDTA-NS irrigation for ten minutes. In the rat model, compared with NS irrigation combined with rifampin (Ti-6Al-4V wire-implanted rats: 60% bacteria survived; HXLPE particle-implanted rats: 63.3% bacteria survived), EDTA-NS irrigation combined with rifampin produced the highest removal rate (Ti-6Al-4V wire-implanted rats: 3.33% bacteria survived; HXLPE particle-implanted rats: 6.67% bacteria survived). In the pig model, compared with NS irrigation combined with rifampin (Ti-6Al-4V plates: 75% bacteria survived; HXLPE bearings: 87.5% bacteria survived), we observed a similar level of biofilm disruption on Ti-6Al-4V plates (25% bacteria survived) and HXLPE bearings (37.5% bacteria survived) after EDTA-NS irrigation combined with rifampin. The in vivo study revealed that the biomass of S. aureus biofilm was significantly reduced when treated with rifampin following irrigation and debridement, as indicated by both the biofilm bacterial burden and crystal violet staining. EDTA-NS irrigation (10 mM/10 min) combined with rifampin effectively removes S. aureus biofilm-associated infections both in vitro and in vivo. Conclusion: EDTA-NS irrigation with or without antibiotics is effective in eradicating S. aureus biofilm-associated infection both ex and in vivo.

AAV-mediated VEGFA overexpression promotes angiogenesis and recovery of locomotor function following spinal cord injury via PI3K/Akt signaling.

Spinal cord injury (SCI) is a disorder of the central nervous system resulting from various factors such as trauma, inflammation, tumors, and other etiologies. This condition leads to impairment in motor, sensory, and autonomic functions below the level of injury. Limitations of current therapeutic approaches prompt an investigation into therapeutic angiogenesis through persistent local expression of proangiogenic factors. Here, we investigated whether overexpression of adeno-associated virus (AAV)-mediated vascular endothelial growth factor A (VEGFA) in mouse SCI promoted locomotor function recovery, and whether the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) pathway was mechanistically involved. Three weeks before SCI, AAV-VEGFA was injected at the T10 level to induce VEGFA overexpression. Neurofunctional, histological, and biochemical assessments were done to determine tissue damage and/or recovery of neuromuscular and behavioral impairments. Daily injections of the PI3K/Akt pathway inhibitor LY294002 were made to assess a possible mechanism. AAV-VEGFA overexpression dramatically improved locomotor function and ameliorated pathological injury caused by SCI. Improved motor-evoked potentials in hindlimbs and more spinal CD31-positive microvessels were observed in AAV-VEGFA-overexpressing mice. LY294002 reduced PI3K and Akt phosphorylation levels and attenuated AAV-VEGFA-related improvements. In conclusion, sustained local AAV-mediated VEGFA overexpression in spinal cord can significantly promote angiogenesis and ameliorate locomotor impairment after SCI in a contusion mouse model through activation of the PI3K/Akt signaling pathway.

Development and external validation of a prediction model for digit replantation failure after traumatic amputations based on a prospective multicenter cohort.

BACKGROUND: Failure of digit replantation after traumatic amputation is difficult to predict. The authors aimed to develop a prognostic model to better identify factors that better predict replantation failure following traumatic digit amputation. MATERIALS AND METHODS: In this multicenter prospective cohort, the authors identified patients who had received digit replantation between 1 January 2015 and 1 January 2019. Univariable and multivariable analyses were performed successively to identify independently predictive factors for failure of replanted digit. To reduce overfitting, the Bayesian information criterion was used to reduce variables in the original model. Nomograms were created with the reduced model after model selection. This model was then internally validated with bootstrap resampling and further externally validated in validation cohort. RESULTS: Digit replantation was failed in 101 of 1062 (9.5%) digits and 146 of 1156 digits (12.6%) in the training and validation cohorts, respectively. The authors found that six independent prognostic variables were associated with digit replantation failure: age, mechanism of injury, ischemia duration, smoking status, amputation pattern (complete or incomplete), and surgeon's experience. The prediction model achieved good discrimination, with concordance indexes of 0.81 (95% CI: 0.76-0.85) and 0.70 (95% CI: 0.65-0.74) in predicting digit failure in the training and validation cohorts, respectively. Calibration curves were well-fitted for both training and validation cohorts. CONCLUSIONS: The proposed prediction model effectively predicted the failure rate of digit replantation for individual digits of all patients. It could assist in selecting the most suitable surgical plan for the patient.

Semaphorin3C identified as mediator of neuroinflammation and microglia polarization after spinal cord injury.

Excessive neuroinflammation after spinal cord injury (SCI) is a major hurdle during nerve repair. Although proinflammatory macrophage/microglia-mediated neuroinflammation plays important roles, the underlying mechanism that triggers neuroinflammation and aggravating factors remain unclear. The present study identified a proinflammatory role of semaphorin3C (SEMA3C) in immunoregulation after SCI. SEMA3C expression level peaked 7 days post-injury (dpi) and decreased by 14 dpi. In vivo and in vitro studies revealed that macrophages/microglia expressed SEMA3C in the local microenvironment, which induced neuroinflammation and conversion of proinflammatory macrophage/microglia. Mechanistic experiments revealed that RAGE/NF-κB was downstream target of SEMA3C. Inhibiting SEMA3C-mediated RAGE signaling considerably suppressed proinflammatory cytokine production, reversed polarization of macrophages/microglia shortly after SCI. In addition, inhibition of SEMA3C-mediated RAGE signaling suggested that the SEMA3C/RAGE axis is a feasible target to preserve axons from neuroinflammation. Taken together, our study provides the first experimental evidence of an immunoregulatory role for SEMA3C in SCI via an autocrine mechanism.

Risk factors for deep vein thrombosis in patients with pelvic or lower-extremity fractures in the emergency intensive care unit.

Introduction: This study aimed to investigate the incidence of deep vein thrombosis (DVT) in patients with pelvic or lower-extremity fractures in the emergency intensive care unit (EICU), explore the independent risk factors for DVT, and investigate the predictive value of the Autar scale for DVT in these patients. Methods: The clinical data of patients with single fractures of the pelvis, femur, or tibia in the EICU from August 2016 to August 2019 were retrospectively examined. The incidence of DVT was statistically analyzed. Logistic regression was used to analyze the independent risk factors for DVT in these patients. The receiver-operating characteristic (ROC) curve was used to evaluate the predictive value of the Autar scale for the risk of DVT. Results: A total of 817 patients were enrolled in this study; of these, 142 (17.38%) had DVT. Significant differences were found in the incidence of DVT among the pelvic fractures, femoral fractures, and tibial fractures (P < 0.001). The multivariate logistic regression analysis showed multiple injuries (OR = 2.210, 95% CI: 1.166-4.187, P = 0.015), fracture site (compared with tibia fracture group, femur fracture group OR = 4.839, 95% CI: 2.688-8.711, P < 0.001; pelvic fracture group OR = 2.210, 95% CI: 1.225-3.988, P = 0.008), and Autar score (OR = 1.198, 95% CI: 1.016-1.353, P = 0.004) were independent risk factors for DVT in patients with pelvic or lower-extremity fractures in the EICU. The area under the ROC curve (AUROC) of the Autar score for predicting DVT was 0.606. When the Autar score was set as the cutoff value of 15.5, the sensitivity and specificity for predicting DVT in patients with pelvic or lower-extremity fractures were 45.1% and 70.7%, respectively. Discussion: Fracture is a high-risk factor for DVT. Patients with a femoral fracture or multiple injuries have a higher risk of DVT. In the case of no contraindications, DVT prevention measures should be taken for patients with pelvic or lower-extremity fractures. Autar scale has a certain predictive value for the occurrence of DVT in patients with pelvic or lower-extremity fractures, but it is not ideal.

Relative efficacy of three different tendon repairs in complete flexor digitorum profundus laceration in Zone I: A randomized controlled study.

Hand flexor tendon injuries are common and biomechanically challenging to achieve good functional outcomes. Several approaches using the Pennington-modified Kessler repair technique have been attempted, but high-level evidence is still lacking. Here, we evaluated the relative efficacy of three versions of the Pennington-modified Kessler technique in repairing complete flexor digitorum profundus (FDP) laceration in Zone 1. We conducted a 2-year, single-center, double-blind, randomized clinical trial involving 85 patients with 105 digits enrolled between June 1, 2017 and January 1, 2019. Eligible participants were 20-60 years of age and underwent tendon repair in the acute phase for complete FDP laceration distal to the insertion of the superficial flexor tendon. The digits were randomized 1:1:1 to three treatment groups: (1) Pennington-modified Kessler repair; (2) Pennington-modified Kessler repair followed by circumferential tendon suture; or (3) Pennington-modified Kessler repair followed by circumferential epitenon suture. The primary endpoint was total active range of motion (TAROM) at 2 years after the initial surgery. The secondary endpoint was the reoperation rate. Compared with group 1, both techniques for peripheral suture were associated with a decrease in TAROM at 2 years after surgery. The total reoperation rates of the three groups were 11.4%, 18.2%, and 17.6%, and we found no significant differences among the three groups possibly due to the limited sample size. Unexpectedly, among participants with complete FDP laceration in Zone I, both circumferential-tendon and circumferential-epitenon sutures caused worsening of TAROM after 2 years. No conclusions can be drawn regarding reoperation rates among the groups. Level of evidence: Therapeutic level I.

Altered cortical thickness and structural covariance networks in upper limb amputees: A graph theoretical analysis.

BACKGROUND: The extensive functional and structural remodeling that occurs in the brain after amputation often results in phantom limb pain (PLP). These closely related phenomena are still not fully understood. METHODS: Using magnetic resonance imaging (MRI) and graph theoretical analysis (GTA), we explored how alterations in brain cortical thickness (CTh) and structural covariance networks (SCNs) in upper limb amputees (ULAs) relate to PLP. In all, 45 ULAs and 45 healthy controls (HCs) underwent structural MRI. Regional network properties, including nodal degree, betweenness centrality (BC), and node efficiency, were analyzed with GTA. Similarly, global network properties, including global efficiency (Eglob), local efficiency (Eloc), clustering coefficient (Cp), characteristic path length (Lp), and the small-worldness index, were evaluated. RESULTS: Compared with HCs, ULAs had reduced CThs in the postcentral and precentral gyri contralateral to the amputated limb; this decrease in CTh was negatively correlated with PLP intensity in ULAs. ULAs showed varying degrees of change in node efficiency in regional network properties compared to HCs (p < 0.005). There were no group differences in Eglob, Eloc, Cp, and Lp properties (all p > 0.05). The real-worldness SCN of ULAs showed a small-world topology ranging from 2% to 34%, and the area under the curve of the small-worldness index in ULAs was significantly different compared to HCs (p < 0.001). CONCLUSION: These results suggest that the topological organization of human CNS functional networks is altered after amputation of the upper limb, providing further support for the cortical remapping theory of PLP.

Transfer of Soleus Muscular Branch of Tibial Nerve to Deep Fibular Nerve to Repair Foot Drop After Common Peroneal Nerve Injury: A Retrospective Study.

OBJECTIVE: Common peroneal nerve (CPN) injury that leads to foot drop is difficult to manage and treat. We present a new strategy for management of foot drop after CPN injury. The soleus muscular branch of the tibial nerve is directly transferred to the deep fibular nerve, providing partial restoration of motor function. METHODS: We retrospectively reviewed eight patients treated for CPN injury between 2017 and 2019. The soleus muscular branch of the tibial nerve was transferred to the deep fibular nerve to repair foot drop. Electrophysiology was conducted, and motor function was assessed. Motor function was evaluated by measuring leg muscle strength during ankle dorsiflexion using the British Medical Research Council (BMRC) grading system and electromyography (EMG). RESULTS: In 10-15 months postoperatively, EMG revealed newly appearing electrical potentials in the tibialis anterior, extensor hallucis longus, and extensor toe longus muscle (N = 7). Two patients achieved BMRC grade of M4 for ankle dorsiflexion, 2 patients achieved M3, 1 patient achieved M2, and 2 patients achieved M1. Four patients showed good functional recovery after surgery and could walk and participate in activities without ankle-foot orthotics. CONCLUSION: Surgical transfer of the soleus muscular branch of the tibial nerve to the deep fibular nerve after CPN injury provides variable improvements in ankle dorsiflexion strength. Despite variable strength gains, 50% of patients achieved BMRC M3 or greater motor recovery, which enabled them to walk without assistive devices.

Platelets mediate trained immunity against bone and joint infections in a mouse model.

AIMS: Trained immunity confers non-specific protection against various types of infectious diseases, including bone and joint infection. Platelets are active participants in the immune response to pathogens and foreign substances, but their role in trained immunity remains elusive. METHODS: We first trained the innate immune system of C57BL/6 mice via intravenous injection of two toll-like receptor agonists (zymosan and lipopolysaccharide). Two, four, and eight weeks later, we isolated platelets from immunity-trained and control mice, and then assessed whether immunity training altered platelet releasate. To better understand the role of immunity-trained platelets in bone and joint infection development, we transfused platelets from immunity-trained mice into naïve mice, and then challenged the recipient mice with Staphylococcus aureus or Escherichia coli. RESULTS: After immunity training, the levels of pro-inflammatory cytokines (tumour necrosis factor alpha (TNF-α), interleukin (IL)-17A) and chemokines (CCL5, CXCL4, CXCL5, CXCL7, CXCL12) increased significantly in platelet releasate, while the levels of anti-inflammatory cytokines (IL-4, IL-13) decreased. Other platelet-secreted factors (e.g. platelet-derived growth factor (PDGF)-AA, PDGF-AB, PDGF-BB, cathepsin D, serotonin, and histamine) were statistically indistinguishable between the two groups. Transfusion of platelets from trained mice into naïve mice reduced infection risk and bacterial burden after local or systemic challenge with either S. aureus or E. coli. CONCLUSION: Immunity training altered platelet releasate by increasing the levels of inflammatory cytokines/chemokines and decreasing the levels of anti-inflammatory cytokines. Transfusion of platelets from immunity-trained mice conferred protection against bone and joint infection, suggesting that alteration of platelet releasate might be an important mechanism underlying trained immunity and may have clinical implications. Cite this article: Bone Joint Res 2022;11(2):73-81.

Triplanar osteotomy combined with proximal tibial transverse transport to accelerate healing of recalcitrant diabetic foot ulcers.

BACKGROUND: Management of recalcitrant diabetic foot ulcers remains challenging. Tibial transverse transport (TTT) is an effective method for enhancing the healing of foot ulcers. This retrospective study reports a novel triplanar osteotomy in the tibia and assesses the clinical outcomes of TTT for diabetic foot ulcers. METHODS: Fifty-nine patients with recalcitrant diabetic foot ulcers were divided into the TTT (32 patients) and control (27 patients) groups. In the TTT group, the patients underwent triplanar osteotomy of the proximal tibia, followed by 2 weeks of medial distraction and 2 weeks of lateral distraction. In the control group, the patients received conventional management, including debridement, revascularization, and reconstruction. Ulcer healing and healing time, amputation, recurrence, and complications were assessed at an 18-month follow-up visit. Computed tomography angiography (CTA) was used to evaluate vessel changes in the lower limbs of patients in the TTT group. RESULTS: The TTT group was superior to the control group in the healing rate (90.6% [29/32] vs. 66.7% [18/27]) and the healing time (4.6 ± 1.7 months vs. 7.4 ± 2.5 months), respectively. The proportions of amputation and recurrence in the TTT group were lower than that in the control group, without statistical difference. After triplanar osteotomy and transverse distraction, CTA demonstrated an increase in small vessels in the wound and ipsilateral limb. All patients achieved satisfactory union of the osteotomized bone fragment after removal of the external fixator. CONCLUSIONS: Triplanar osteotomy combined with proximal tibial transverse distraction accelerates wound healing and limb salvage caused by severe and recalcitrant diabetic foot ulcers. Triplanar osteotomy not only increases the bone contact area, which is beneficial for rapid bone reconstruction, but also preserves the vascularization of the bone fragment and substantially facilitates capillary angiogenesis during distraction. These results suggest that triplanar osteotomy followed by tibial transverse distraction is an effective method for treating diabetic foot ulcers.

Mitochondrial-targeting antioxidant MitoQ modulates angiogenesis and promotes functional recovery after spinal cord injury.

BACKGROUND: In traumatic spinal cord injury (SCI), secondary injuries, including cellular death, mitochondrial dysfunction, and vascular injury, have been considered as important causes of impaired functional recovery after SCI. Postinjury angiogenesis has been considered to be a potential strategy for SCI treatment. New-born vessels may play a key role in nerve regeneration, which indicates the importance of angiogenesis in nerve regeneration. Recent studies have revealed the crosstalk between reactive oxygen species (ROS) and angiogenesis. As the main source of cellular ROS, mitochondria have been proven to be essential to the angiogenesis process. METHODS: SCI was established in a T10 clip-compression animal model. Then, the animals received an intraperitoneal injection of MitoQ (5 mg/kg/d) on Days 0, 1, and 2 after surgery. The Basso Mouse Scale (BMS) score and footprint analysis (CatWalk analysis) were performed to evaluate functional recovery after SCI. Immunofluorescence and fluorescence assays (LEL-FITC/CD31/Iba-1/Neurofilament) were performed to evaluate angiogenesis, microglia activation and neural regeneration. RT-qPCR (VEGFR-1, VEGFR-2 and VEGFA) was performed to evaluate angiogenesis-related factor in injured spinal cord. ATP production assay and western-blotting assay (Mfn-1 and Drp-1) were performed to evaluate mitochondrial function in the injured spinal cord. BV2 cells were used as in vitro cell model. After receiving TBHP or TBHP-MitoQ treatment, ELISA and immunofluorescence assays were used to evaluate the level of VEGFA secretion from BV2 cells. A coculture system of HUVECs and BV2 cells was established. Tube formation assays and immunofluorescence assays (CD31) were performed on HUVECs in a coculture system to evaluate angiogenesis promotion. ATP production assays were performed to evaluate mitochondrial function in BV2 cells. MitoSOX Red and DCFH-DA staining were performed to evaluate mitochondrial and cellular ROS. RESULTS: In vitro MitoQ promoted the secretion of VEGFA from BV2 cells, which was verified through ELISA and immunofluorescence assays. The angiogenic promotion of MitoQ-treated BV2 cells was evaluated by tube formation and immunofluorescence assays (CD31) in a coculture system of BV2 cells and HUVECs. MitoQ inhibited cellular and mitochondrial-derived ROS in TBHP-treated BV2 cells. ATP production was increased in MitoQ-treated BV2 cells. To verify MitoQ's effect in vivo, a T10 clip-compression animal model was established successfully. MitoQ significantly promoted functional recovery, as shown by the BMS assay and gait analysis. The promotion of neural regeneration was identified through immunofluorescence assay of neurofilament. Immunofluorescence and fluorescence assays (LEL-FITC/CD31/Iba-1) and RT-qPCR (VEGFR-1, VEGFR-2 and VEGFA) indicated that MitoQ could promote angiogenesis and inhibit macrophage/microglia activation in lesion-site after SCI. Enhanced ATP production and increased Mfn-1 with decreased Drp-1 protein expression showed MitoQ could promote mitochondrial function in SCI. CONCLUSION: The mitochondrial-specific antioxidant MitoQ promotes functional recovery and tissue preservation through the enhancement of angiogenesis with the modification of mitochondrial function after SCI.