Synovial fluid neutrophil extracellular traps could improve the diagnosis of periprosthetic joint infection

AIMS

This study aimed to explore the diagnostic value of synovial fluid neutrophil extracellular traps (SF-NETs) in periprosthetic joint infection (PJI) diagnosis, and compare it with that of microbial culture, serum ESR and CRP, synovial white blood cell (WBC) count, and polymorphonuclear neutrophil percentage (PMN%).

METHODS

In a single health centre, patients with suspected PJI were enrolled from January 2013 to December 2021. The inclusion criteria were: 1) patients who were suspected to have PJI; 2) patients with complete medical records; and 3) patients from whom sufficient synovial fluid was obtained for microbial culture and NET test. Patients who received revision surgeries due to aseptic failure (AF) were selected as controls. Synovial fluid was collected for microbial culture and SF-WBC, SF-PNM%, and SF-NET detection. The receiver operating characteristic curve (ROC) of synovial NET, WBC, PMN%, and area under the curve (AUC) were obtained; the diagnostic efficacies of these diagnostic indexes were calculated and compared.

RESULTS

The levels of SF-NETs in the PJI group were significantly higher than those of the AF group. The AUC of SF-NET was 0.971 (95% confidence interval (CI) 0.903 to 0.996), the sensitivity was 93.48% (95% CI 82.10% to 98.63%), the specificity was 96.43% (95% CI 81.65% to 99.91%), the accuracy was 94.60% (95% CI 86.73% to 98.50%), the positive predictive value was 97.73%, and the negative predictive value was 90%. Further analysis showed that SF-NET could improve the diagnosis of culture-negative PJI, patients with PJI who received antibiotic treatment preoperatively, and fungal PJI.

CONCLUSION

SF-NET is a novel and ideal synovial fluid biomarker for PJI diagnosis, which could improve PJI diagnosis greatly.Cite this article: Bone Joint Res 2023;12(2):113-120.

Radiodynamic therapy with acridine orange local administration as a new treatment option for primary and secondary bone tumours

AIMS

Acridine orange (AO) demonstrates several biological activities. When exposed to low doses of X-ray radiation, AO increases the production of reactive radicals (radiodynamic therapy (AO-RDT)). We elucidated the efficacy of AO-RDT in breast and prostate cancer cell lines, which are likely to develop bone metastases.

METHODS

We used the mouse osteosarcoma cell line LM8, the human breast cancer cell line MDA-MB-231, and the human prostate cancer cell line PC-3. Cultured cells were exposed to AO and radiation at various concentrations followed by various doses of irradiation. The cell viability was then measured. In vivo, each cell was inoculated subcutaneously into the backs of mice. In the AO-RDT group, AO (1.0 μg) was locally administered subcutaneously around the tumour followed by 5 Gy of irradiation. In the radiation group, 5 Gy of irradiation alone was administered after macroscopic tumour formation. The mice were killed on the 14th day after treatment. The change in tumour volume by AO-RDT was primarily evaluated.

RESULTS

The viability of LM8, MDA-MB-231, and PC-3 cells strongly decreased at AO concentration of 1.0 μg/ml and a radiation dose of 5 Gy. In xenograft mouse model, the AO-RDT also showed a strong cytocidal effect on tumour at the backside in osteosarcoma, breast cancer, and prostate cancer. AO-RDT treatment was more effective for tumour control than radiotherapy in breast cancer.

CONCLUSION

AO-RDT was effective in preventing the proliferation of osteosarcoma, breast cancer, and prostate cancer cell lines in vitro. The reduction in tumour volume by AO-RDT was also confirmed in vivo.Cite this article: Bone Joint Res 2022;11(10):685-692.

Comparison of carbon fibre and titanium intramedullary nails in orthopaedic oncology

Aims

Due to their radiolucency and favourable mechanical properties, carbon fibre nails may be a preferable alternative to titanium nails for oncology patients. We aim to compare the surgical characteristics and short-term results of patients who underwent intramedullary fixation with either a titanium or carbon fibre nail for pathological long-bone fracture.

Methods

This single tertiary-institutional, retrospectively matched case-control study included 72 patients who underwent prophylactic or therapeutic fixation for pathological fracture of the humerus, femur, or tibia with either a titanium (control group, n = 36) or carbon fibre (case group, n = 36) intramedullary nail between 2016 to 2020. Patients were excluded if intramedullary fixation was combined with any other surgical procedure/fixation method. Outcomes included operating time, blood loss, fluoroscopic time, and complications. Fisher’s exact test and Mann-Whitney U test were used for categorical and continuous outcomes, respectively.

Results

Patients receiving carbon nails as compared to those receiving titanium nails had higher blood loss (median 150 ml (interquartile range (IQR) 100 to 250) vs 100 ml (IQR 50 to 150); p = 0.042) and longer fluoroscopic time (median 150 seconds (IQR 114 to 182) vs 94 seconds (IQR 58 to 124); p = 0.001). Implant complications occurred in seven patients (19%) in the titanium group versus one patient (3%) in the carbon fibre group (p = 0.055). There were no notable differences between groups with regard to operating time, surgical wound infection, or survival.

Conclusion

This pilot study demonstrates a non-inferior surgical and short-term clinical profile supporting further consideration of carbon fibre nails for pathological fracture fixation in orthopaedic oncology patients. Given enhanced accommodation of imaging methods important for oncological surveillance and radiation therapy planning, as well as high tolerances to fatigue stress, carbon fibre implants possess important oncological advantages over titanium implants that merit further prospective investigation.

Level of evidence: III, Retrospective study

Cite this article: Bone Jt Open 2022;3(8):648–655.

A comparison of the post-fusion outcome of patients with early-onset scoliosis treated with traditional and magnetically controlled growing rods

AIMS

The aim of this study was to compare the clinical and radiological outcomes of patients with early-onset scoliosis (EOS), who had undergone spinal fusion after distraction-based spinal growth modulation using either traditional growing rods (TGRs) or magnetically controlled growing rods (MCGRs).

METHODS

We undertook a retrospective review of skeletally mature patients who had undergone fusion for an EOS, which had been previously treated using either TGRs or MCGRs. Measured outcomes included sequential coronal T1 to S1 height and major curve (Cobb) angle on plain radiographs and any complications requiring unplanned surgery before final fusion.

RESULTS

We reviewed 43 patients (63% female) with a mean age of 6.4 years (SD 2.6) at the index procedure, and 12.2 years (SD 2.2) at final fusion. Their mean follow-up was 8.1 years (SD 3.4). A total of 16 patients were treated with MCGRs and 27 with TGRs. The mean number of distractions was 7.5 in the MCGR group and ten in the TGR group (p = 0.471). The mean interval between distractions was 3.4 months in the MCGR group and 8.6 months in the TGR group (p < 0.001). The mean Cobb angle had improved by 25.1° in the MCGR group and 23.2° in TGR group (p = 0.664) at final follow-up. The mean coronal T1 to S1 height had increased by 16% in the MCGR group and 32.9% in TGR group (p = 0.001), although the mean T1 to S1 height achieved at final follow-up was similar in both. Unplanned operations were needed in 43.8% of the MCGR group and 51.2% of TGR group (p = 0.422).

CONCLUSION

In this retrospective, single-centre review, there were no significant differences in major curve correction or gain in spinal height at fusion. Although the number of planned procedures were fewer in patients with MCGRs, the rates of implant-related complications needing unplanned revision surgery were similar in the two groups. Cite this article: Bone Joint J 2022;104-B(2):257-264.

A comparison of clinical outcomes between additional excision after unplanned and planned excisions in patients with soft-tissue sarcoma of the limb : a propensity matching cohort study

AIMS

Patients with soft-tissue sarcoma (STS) who undergo unplanned excision (UE) are reported to have worse outcomes than those who undergo planned excision (PE). However, others have reported that patients who undergo UE may have similar or improved outcomes. These discrepancies are likely to be due to differences in characteristics between the two groups of patients. The aim of the study is to compare patients who underwent UE and PE using propensity score matching, by analyzing data from the Japanese Bone and Soft Tissue Tumor (BSTT) registry.

METHODS

Data from 2006 to 2016 was obtained from the BSTT registry. Only patients with STS of the limb were included in the study. Patients with distant metastasis at the initial presentation and patients with dermatofibrosarcoma protuberans and well-differentiated liposarcoma were excluded from the study.

RESULTS

A total of 4,483 patients with STS of the limb were identified before propensity score matching. There were 355 patients who underwent UE and 4,128 patients who underwent PE. The five-year disease-specific survival (DSS) rate was significantly better in the patients who received additional excision after UE than in those who underwent PE. There was no significant difference in local recurrence-free survival (LRFS) between the two groups. After propensity score matching, a new cohort of 355 patients was created for both PE and UE groups, in which baseline covariates were appropriately balanced. Reconstruction after tumour excision was frequently performed in patients who underwent additional excision after UE. There were no significant differences in DSS and LRFS between the patients who underwent PE and those who had an additional excision after UE.

CONCLUSION

Using propensity score matching, patients with STS of the limb who underwent additional excision after UE did not experience higher mortality and local failure than those who underwent PE. Reconstruction may be necessary when additional excision is performed. Cite this article: Bone Joint J 2021;103-B(12):1809-1814.

Functional outcome of routine versus on-demand removal of the syndesmotic screw: a multicentre randomized controlled trial

Aims

The aim of this study was to investigate whether on-demand removal (ODR) is noninferior to routine removal (RR) of syndesmotic screws regarding functional outcome.

Methods

Adult patients (aged above 17 years) with traumatic syndesmotic injury, surgically treated within 14 days of trauma using one or two syndesmotic screws, were eligible (n = 490) for inclusion in this randomized controlled noninferiority trial. A total of 197 patients were randomized for either ODR (retaining the syndesmotic screw unless there were complaints warranting removal) or RR (screw removed at eight to 12 weeks after syndesmotic fixation), of whom 152 completed the study. The primary outcome was functional outcome at 12 months after screw placement, measured by the Olerud-Molander Ankle Score (OMAS).

Results

There were 152 patients included in final analysis (RR = 73; ODR = 79). Of these, 59.2% were male (n = 90), and the mean age was 46.9 years (SD 14.6). Median OMAS at 12 months after syndesmotic fixation was 85 (interquartile range (IQR) 60 to 95) for RR and 80 (IQR 65 to 100) for ODR. The noninferiority test indicated that the observed effect size was significantly within the equivalent bounds of -10 and 10 scale points (p < 0.001) for both the intention-to-treat and per-protocol, meaning that ODR was not inferior to RR. There were significantly more complications in the RR group (12/73) than in the ODR group (1/79) (p = 0.007).

Conclusion

ODR of the syndesmotic screw is not inferior to routine removal when it comes to functional outcome. Combined with the high complication rate of screw removal, this offers a strong argument to adopt on demand removal as standard practice of care after syndesmotic screw fixation.

Cite this article: Bone Joint J 2021;103-B(11):1709–1716.

Theatre efficiency in COVID-19 pandemic conditions: The collaborative experience of four level 1 major trauma centres in the UK

Aims

As the world continues to fight successive waves of COVID-19 variants, we have seen worldwide infections surpass 100 million. London, UK, has been severely affected throughout the pandemic, and the resulting impact on the NHS has been profound. The aim of this study is to evaluate the impact of COVID-19 on theatre productivity across London’s four major trauma centres (MTCs), and to assess how the changes to normal protocols and working patterns impacted trauma theatre efficiency.

Methods

This was a collaborative study across London’s MTCs. A two-month period was selected from 5 March to 5 May 2020. The same two-month period in 2019 was used to provide baseline data for comparison. Demographic information was collected, as well as surgical speciality, procedure, time to surgery, type of anaesthesia, and various time points throughout the patient journey to theatre.

Results

In total, 1,243 theatre visits were analyzed as part of the study. Of these, 834 patients presented in 2019 and 409 in 2020. Fewer open reduction and internal fixations were performed in 2020 (33.5% vs 38.2%), and there was an increase in the number of orthoplastic cases in 2020 (8.3% vs 2.2%), both statistically significant results (p < 0.000). There was a statistically significant increase in median time from 2019 to 2020, between sending for a patient and their arrival to the anaesthetic room (29 vs 35 minutes; p = 0.000). Median time between arrival in the anaesthetic room and commencement of anaesthetic increased (7 to 9 minutes; p = 0.104).

Conclusion

Changes in working practices necessitated by COVID-19 led to modest delays to all aspects of theatre use, and consequently theatre efficiency. However, the reality is that the major concerns of impact of service did not occur to the levels that were expected.

Cite this article: Bone Jt Open 2021;2(10):886–892.

Robotic-arm assisted THA can achieve precise cup positioning in developmental dysplasia of the hip : a case control study

AIMS

This study aimed to evaluate the accuracy of implant placement with robotic-arm assisted total hip arthroplasty (THA) in patients with developmental dysplasia of the hip (DDH).

METHODS

The study analyzed a consecutive series of 69 patients who underwent robotic-arm assisted THA between September 2018 and December 2019. Of these, 30 patients had DDH and were classified according to the Crowe type. Acetabular component alignment and 3D positions were measured using pre- and postoperative CT data. The absolute differences of cup alignment and 3D position were compared between DDH and non-DDH patients. Moreover, these differences were analyzed in relation to the severity of DDH. The discrepancy of leg length and combined offset compared with contralateral hip were measured.

RESULTS

The mean values of absolute differences (postoperative CT-preoperative plan) were 1.7° (standard deviation (SD) 2.0) (inclination) and 2.5° (SD 2.1°) (anteversion) in DDH patients, and no significant differences were found between non-DDH and DDH patients. The mean absolute differences for 3D cup position were 1.1 mm (SD 1.0) (coronal plane) and 1.2 mm (SD 2.1) (axial plane) in DDH patients, and no significant differences were found between two groups. No significant difference was found either in cup alignment between postoperative CT and navigation record after cup screws or in the severity of DDH. Excellent restoration of leg length and combined offset were achieved in both groups.

CONCLUSION

We demonstrated that robotic-assisted THA may achieve precise cup positioning in DDH patients, and may be useful in those with severe DDH. Cite this article: Bone Joint Res 2021;10(10):629-638.

The influence of hospital-level variables on hip fracture outcomes

AIMS

The aim of this study was to determine the impact of hospital-level service characteristics on hip fracture outcomes and quality of care processes measures.

METHODS

This was a retrospective analysis of publicly available audit data obtained from the National Hip Fracture Database (NHFD) 2018 benchmark summary and Facilities Survey. Data extraction was performed using a dedicated proforma to identify relevant hospital-level care process and outcome variables for inclusion. The primary outcome measure was adjusted 30-day mortality rate. A random forest-based multivariate imputation by chained equation (MICE) algorithm was used for missing value imputation. Univariable analysis for each hospital level factor was performed using a combination of Tobit regression, Siegal non-parametric linear regression, and Mann-Whitney U test analyses, dependent on the data type. In all analyses, a p-value < 0.05 denoted statistical significance.

RESULTS

Analyses included 176 hospitals, with a median of 366 hip fracture cases per year (interquartile range (IQR) 280 to 457). Aggregated data from 66,578 patients were included. The only identified hospital-level variable associated with the primary outcome of 30-day mortality was hip fracture trial involvement (no trial involvement: median 6.3%; trial involvement: median 5.7%; p = 0.039). Significant key associations were also identified between prompt surgery and presence of dedicated hip fracture sessions; reduced acute length of stay and both a higher number of hip fracture cases per year and more dedicated hip fracture operating lists; Best Practice Tariff attainment and greater number of hip fracture cases per year, more dedicated hip fracture operating lists, presence of a dedicated hip fracture ward, and hip fracture trial involvement.

CONCLUSION

Exploratory analyses have identified that improved outcomes in hip fracture may be associated with hospital-level service characteristics, such as hip fracture research trial involvement, larger hip fracture volumes, and the use of theatre lists dedicated to hip fracture surgery. Further research using patient level data is warranted to corroborate these findings. Cite this article: Bone Joint J 2021;103-B(10):1627-1632.

Statistical Methods for Analysis of Protein Microarray Data Using R

This chapter aims to provide statistical methods for analyzing protein microarray data. It uses a publicly available protein array dataset and emphasizes practical applications in statistics using R, a statistical software. A wide range of statistical methods will be demonstrated, including descriptive statistics, hypothesis testing, false discovery rate, receiver operating characteristic curve, correlation, visualization, and power analysis. The R code used to perform the statistical analyses will be provided.

[Influence of Meteorological Conditions on Ozone Pollution at Shangdianzi Station Based on Weather Classification]

As a typical secondary pollutant, tropospheric ozone has become the primary pollutant in Beijing in spring and summer, and meteorological factors are one of the main factors affecting the change in concentration. Using atmospheric composition and meteorological observation data from 2008 to 2017, the weather types in Beijing were divided into six categories by Lamb classification and Mann-Whitney U test. Among these, the mean and extreme values of ozone concentration of SWW and C types at Shangdianzi station were the highest, and the highest frequency was from April to September, with a total of 47.4%. The main contribution weights of the two types were determined by a multiple stepwise regression equation. The southwest wind prevailed in 54.0% of SWW and C types, and the newly discharged pollutants and secondary aging air masses were continuously transported by the southwest air flow. The vertical velocity zero layer appeared near 850 hPa. The horizontal and vertical meteorological conditions were conducive to the transport, accumulation, and secondary generation of ozone. The northeast wind prevailed in 64.7% of AN and ESN types, and the air masses source was clean. The same subsidence movement and air divergence prevailed above 1000 hPa. The discharged pollutants can also be diluted and diffused quickly, and the ozone concentration was at a low value. Taking the NW type on May 3, 2015 as an example, although the northwest air flow prevailed on the ground, with clean source, the residual high concentration of ozone above the boundary layer was transported to the near ground through the vertical subsidence of the atmosphere, resulting in the high concentration of ozone on some days.

Nonparametric response-adaptive randomization for continuous responses

Many response-adaptive randomization procedures have been proposed and studied over the past few decades. However, most of these procedures are based on parametric structure and do not directly apply to nonparametric models. In this paper, we propose a response-adaptive randomization procedure based on Mann-Whitney U test statistic. Under widely satisfied conditions, we derive asymptotic properties of the randomization procedure and further obtain power functions in form under Mann-Whitney U test. Simulations show the proposed procedure is more robust and more ethical than classical response-adaptive randomization procedures in some circumstances. Advantages of the procedure are also illustrated in a redesigned real clinical trial.

Confidence intervals of the Mann-Whitney parameter that are compatible with the Wilcoxon-Mann-Whitney test

For the two-sample problem, the Wilcoxon-Mann-Whitney (WMW) test is used frequently: it is simple to explain (a permutation test on the difference in mean ranks), it handles continuous or ordinal responses, it can be implemented for large or small samples, it is robust to outliers, it requires few assumptions, and it is efficient in many cases. Unfortunately, the WMW test is rarely presented with an effect estimate and confidence interval. A natural effect parameter associated with this test is the Mann-Whitney parameter, φ = Pr[ X<Y ] + 0.5 Pr[X = Y ]. Ideally, we desire confidence intervals on φ that are compatible with the WMW test, meaning the test rejects at level α if and only if the 100(1 - α)% confidence interval on the Mann-Whitney parameter excludes 1/2. Existing confidence interval procedures on φ are not compatible with the usual asymptotic implementation of the WMW test that uses a continuity correction nor are they compatible with exact WMW tests. We develop compatible confidence interval procedures for the asymptotic WMW tests and confidence interval procedures for some exact WMW tests that appear to be compatible. We discuss assumptions and interpretation of the resulting tests and confidence intervals. We provide the wmwTest function of the asht R package to calculate all of the developed confidence intervals.

Causal estimands and confidence intervals associated with Wilcoxon-Mann-Whitney tests in randomized experiments

Although the P value from a Wilcoxon-Mann-Whitney test is used often with randomized experiments, it is rarely accompanied with a causal effect estimate and its confidence interval. The natural parameter for the Wilcoxon-Mann-Whitney test is the Mann-Whitney parameter, ϕ, which measures the probability that a randomly selected individual in the treatment arm will have a larger response than a randomly selected individual in the control arm (plus an adjustment for ties). We show that the Mann-Whitney parameter may be framed as a causal parameter and show that it is not equal to a closely related and nonidentifiable causal effect, ψ, the probability that a randomly selected individual will have a larger response under treatment than under control (plus an adjustment for ties). We review the paradox, first expressed by Hand, that the ψ parameter may imply that the treatment is worse (or better) than control, while the Mann-Whitney parameter shows the opposite. Unlike the Mann-Whitney parameter, ψ is nonidentifiable from a randomized experiment. We review some nonparametric assumptions that rule out Hand's paradox through bounds on ψ and use bootstrap methods to make inferences on those bounds. We explore the relationship of the proportional odds parameter to Hand's paradox, showing that the paradox may occur for proportional odds parameters between 1/9 and 9. Thus, large effects are needed to ensure that if treatment appears better by the Mann-Whitney parameter, then treatment improves responses in most individuals. We demonstrate these issues using a vaccine trial.

Modified Wilcoxon-Mann-Whitney Test and Power against Strong Null

The Wilcoxon-Mann-Whitney (WMW) test is a popular rank-based two-sample testing procedure for the strong null hypothesis that the two samples come from the same distribution. A modified WMW test, the Fligner-Policello (FP) test, has been proposed for comparing the medians of two populations. A fact that may be underappreciated among some practitioners is that the FP test can also be used to test the strong null like the WMW. In this paper we compare the power of the WMW and FP tests for testing the strong null. Our results show that neither test is uniformly better than the other and that there can be substantial differences in power between the two choices. We propose a new, modified WMW test that combines the WMW and FP tests. Monte Carlo studies show that the combined test has good power compared to either the WMW and FP test. We provide a fast implementation of the proposed test in an open-source software. Supplementary materials are available online.

The polymorphisms in serotonin-related genes (5-HT₂A and SERT) and the prevalence of depressive symptoms in obese patients

As overweight and obesity are a growing problem in industrialized societies, they become a main focus of many studies. The aim of this study was to determine whether there is an association between the occurrence of polymorphisms in serotonin-related genes and the prevalence of depressive symptoms in obese patients. Two polymorphisms were tested: a 44-bp insertion/deletion in the serotonin transporter (SERT) gene and a single-nucleotide variation (1438G/A) in the serotonin 2A receptor (5-HT2A) gene. The study involved 180 patients (41 men; 139 women) previously diagnosed as obese. All patients were subjected to clinical, biochemical, and neuropsychological evaluation and genotyping. Amplification of the gene fragments was obtained by the polymerase chain reaction (PCR) method. Products of the genotyping were separated via electrophoresis. The intensity of depressive symptoms was measured using the Beck Depression Inventory (BDI) and Hamilton Depression Scale (HAM-D). Clinically relevant depressive symptoms were diagnosed in 39% of subjects. The lowest intensities of depressive symptoms were ascertained in the group with the least advanced obesity, but this trend was statistically insignificant. Small differences were observed in obesity indicators among three groups of patients with various genotypes of the SERT gene, but these differences were also statistically insignificant. Furthermore, in the context of the intensity of depressive symptoms, no significant associations were observed in these two groups. Furthermore, no statistically significant differences were observed among specific obesity parameters and intensity of depressive symptoms as a function of the 5-HT2A gene polymorphism. To conclude, depressive symptoms were prevalent in obese participants: 39% of subjects experienced symptoms of clinical relevance. However, no significant associations were observed between 5-HT2A and SERT gene polymorphisms and depressive symptoms in this study group.