Arthroplasty Revision Surgery Research Articles

Synovial Fluid Leukocytes as Diagnostic Marker in Periprosthetic Shoulder Infection

BackgroundLimited data exist regarding the diagnostic accuracy of synovial fluid leukocyte count (SFLC) in diagnosing periprosthetic shoulder infection (PSI). The main objective of this study was to determine the diagnostic value of leukocyte count at a common threshold of 3 cells/nL and the optimal cut-off value. MethodsPatients, who underwent shoulder arthroplasty revision surgery and aspiration with SFLC between 2012 and 2023 were retrospectively included. The International Consensus Meeting (ICM) 2018 definition was used to characterize infection status for SFLC threshold and synovial fluid neutrophil percentage (SFNP). Sensitivity and specificity were presented using cross tabulation. The area under the curve was calculated, and the optimal cut-off was determined using maximized Youden Index. Results35 cases with an average age of 71 years (43% male) were included in our study. At a threshold of 3 cells/nL, SFLC showed a sensitivity of 70% and specificity of 83%. The corresponding positive and negative predictive values (PPV, NPV) were 89% and 59%. We found the optimal cut-off for our cohort at 4.7 cells/nL, increasing specificity to 92% while maintaining sensitivity at 70% (PPV = 94%, NPV = 61%). SFNP at a cut-off of 80% demonstrated 50% sensitivity and 91% specificity, with corresponding PPV and NPV of 92% and 48%. The optimum threshold for SFNP was 54%, which had a sensitivity of 77% and a specificity of 64%, as well as a PPV of 81%, and NPV of 58%. The area under the curve was 0.72 for SFLC and 0.74 for SFNP. Sonication detected pathogens in 63% of cases, while 57% of all cases showed positive tissue cultures and 43% positive aspirate cultures. Especially the most frequently found microorganism, Cutibacterium acnes, was detected less often in aspirate culture. ConclusionsSFLC shows good specificity but moderate sensitivity for diagnosing PSI when using a threshold of 4.7 cells/nL. Therefore, it can serve as a confirmatory test for diagnosing PSI but not for ruling out infection.

Evaluation of interleukin-6 in synovial fluid in periprosthetic joint infection of the elbow.

Searching for quick determinable biomarkers with high sensitivity and specificity is necessary to improve and optimise the early diagnosis of periprosthetic elbow infection (PEI). Therefore, this study's objective was to evaluate the diagnostic value of synovial fluid interleukin-6 (IL-6) levels for diagnosing PEI in total elbow arthroplasty. Twelve prospective enrolled patients underwent total elbow arthroplasty revision surgery, during which synovial fluid was obtained. Between the initial implantation and the revision procedure were 33.5 ± 41months (range, 2-144months). Synovial fluid was collected for immediate IL-6 analysis parallel to the revision surgery. Furthermore, microbiological samples were obtained and analysed. Two groups were defined based on the microbiological results: non-infection and infection group. The ability of synovial fluid IL-6 analysis to predict infection status was explored using receiver operating characteristic curves and further statistical analysis. Synovial fluid IL-6 analysis had a good diagnostic accuracy of 83% for PEI with an area under the curve of 0,79 and an ideal cutoff value (determined using Youden's criterion) of 15244pg/mL. This is the first study to clinically evaluate IL-6 as a diagnostical marker for periprosthetic joint infection (PJI) in total elbow arthroplasty. Our results suggest a good accuracy and high sensitivity for IL-6 to identify a PEI. The analysis of IL-6 can improve surgical decision-making regarding managing total elbow arthroplasty in terms of one- or two-staged revision. IL-6 can play an important role in the perioperative differentiation of infected and non-infected situations.

Drop in survivorship 13 years after AMIC procedures in aligned knees: A long-term follow-up.

Autologous matrix-induced chondrogenesis (AMIC) showed promising short-term results comparable to microfracture. This study aims to assess the 19-year outcomes of AMIC, addressing the lack of long-term data. Retrospective cohort of 34 knees treated with AMIC underwent a 19-year follow-up. The primary outcome was AMIC survival, considering total knee arthroplasty as a failure event. Survival analysis for factors that were associated with longer survival of the AMIC was also performed. Clinical and radiological outcome scores were analysed for the AMIC group. Twenty-three knees were available for follow-up analysis. Of these, 14 (61%) underwent revision surgery for total knee arthroplasty (TKA). The mean time was 13.3 ± 2.5 years (range: 9-17 years). Secondary outcomes showed that increased age at surgery (hazard ratio [HR]: 1.05; p = 0.021) and larger defect size (HR: 1.95; p = 0.018) were risk factors for failure. Concomitant proximal tibial osteotomy (HR: 0.22; p = 0.019) was associated with longer survival. The remaining nine knees (39%) were analysed as a single group. The mean clinical score atfollow-up of 18.6 ± 0.9 SD years was 79.5 ± 19.7 SD for the Lysholm score, 1.8 ± 1.5 SD for the visual analog scale score, 74.2 ± 22.4 SD for the KOOS scoreand a median of 3 (range: 3-4) for the Tegner activity scale. The mean survival time of 13.3 years indicates the durability of AMIC in properly aligned knees. Nonetheless, despite a 61% conversion to TKA, the knees that persisted until the 19-year follow-up remained stable, underscoring the procedure's longevity and consistent clinical outcomes. Level IV.

Is there sufficient evidence to support the use of antibiotic holiday just before the second stage of an infected total hip or knee arthroplasty revision surgery?

The practice of implementing an antibiotic holiday before the second stage of hip or knee arthroplasty is currently controversial due to limited evidence for this approach, as per the International Consensus Meeting 2018 on Musculoskeletal Infection. A greater understanding of this issue could augment the quality of Alrayes and Sukeik's mini-review (2023) on diagnosing, managing, and treating periprosthetic knee infections. However, a significant lack of literature exists concerning the optimal duration for the antibiotic holiday, calling for more research before establishing any clinical guidelines.

Hydrogen Peroxide May Reduce the Risk for Revision Surgery and Infection in Primary Shoulder Arthroplasty: Two-year Follow-up From a Prospective, Blinded, Controlled Trial.

The purpose of this study was to determine whether the addition of hydrogen peroxide to the preoperative skin preparation for primary total shoulder arthroplasty is associated with a difference in patient-reported outcomes, risk for postoperative infection, and risk for revision surgery at a minimum of 2-year follow-up. This was a prospective, blinded, and controlled trial, which included a consecutive series of patients undergoing primary shoulder arthroplasty. The control group underwent standard sterile skin preparation using ethyl alcohol and ChloraPrep applicators, and the peroxide group had the same preparation with the addition of hydrogen peroxide between the alcohol and ChloraPrep applications. We then compared patient-reported outcome scores (American Shoulder and Elbow Surgeons Shoulder Score [ASES], simple shoulder test [SST], visual analog scale [VAS]), infections, and revision surgeries between the two groups at 2-year follow-up. Of the 61 patients included in the original study, 52 of 58 (85%) living patients agreed to participate in this study. No preoperative differences were observed between groups. No difference was observed in ASES, SST, or VAS scores at 2 years. More revision surgeries were done in the control group (7 versus 2, P = 0.268) and Cutibacterium acnes infections (2 versus 0, P = 0.168). The addition of hydrogen peroxide to the preoperative skin preparation before primary shoulder arthroplasty is safe, and additional research is warranted to investigate whether it may decrease the risk for revision surgery and postoperative C acnes infection. III.

3D preoperative predictions of in vivo hip stability and edge loading for neutral and lipped liners.

Hip dislocation is one of the leading causes of failure and revision surgery for total hip arthroplasty. To reduce dislocation rates, lipped liners have been designed with an elevated portion of the rim, to increase jump distance and maintain greater contact area. While it has been documented that lipped liners help reduce dislocation, the objective of this study is to investigate whether lipped liners also help reduce smaller instances of hip micromotion, separation, and edge loading. This study uses an advanced three-dimensionalpreoperative planning tool to analyze 10 patients, each implanted with both a neutral and lipped liner. Patients within the simulation performed stance phase of gait, and each cup was implanted with the rotation center aligned with the preoperative acetabulum center as well as shifted medially by 2, 4, 6, 8, and 10 mm, yielding 120 total simulations. Specific postoperative outcomes-of-interest included specified component offset, resultant in vivo hip forces, hip separation, and contact area to evaluate edge loading. The planner predicted a reduction in hip separation and an increase in articulating contact area for when using a lipped liner compared to a neutral liner. Additionally, regardless of liner type, increases in hip separation corresponded to decreases in contact area, therefore resulting in edge loading of the liner. Together, this indicates that improper component alignment and offsets may lead to an increase in hip separation and edge loading, but the use of a lipped liner may provide improved stability and resistance to this micromotion.

High accuracy of positioning custom triflange acetabular components in tumour and total hip arthroplasty revision surgery.

Custom triflange acetabular components (CTACs) play an important role in reconstructive orthopaedic surgery, particularly in revision total hip arthroplasty (rTHA) and pelvic tumour resection procedures. Accurate CTAC positioning is essential to successful surgical outcomes. While prior studies have explored CTAC positioning in rTHA, research focusing on tumour cases and implant flange positioning precision remains limited. Additionally, the impact of intraoperative navigation on positioning accuracy warrants further investigation. This study assesses CTAC positioning accuracy in tumour resection and rTHA cases, focusing on the differences between preoperative planning and postoperative implant positions. A multicentre observational cohort study in Australia between February 2017 and March 2021 included consecutive patients undergoing acetabular reconstruction with CTACs in rTHA (Paprosky 3A/3B defects) or tumour resection (including Enneking P2 peri-acetabular area). Of 103 eligible patients (104 hips), 34 patients (35 hips) were analyzed. CTAC positioning was generally accurate, with minor deviations in cup inclination (mean 2.7°; SD 2.84°), anteversion (mean 3.6°; SD 5.04°), and rotation (mean 2.1°; SD 2.47°). Deviation of the hip centre of rotation (COR) showed a mean vector length of 5.9 mm (SD 7.24). Flange positions showed small deviations, with the ischial flange exhibiting the largest deviation (mean vector length of 7.0 mm; SD 8.65). Overall, 83% of the implants were accurately positioned, with 17% exceeding malpositioning thresholds. CTACs used in tumour resections exhibited higher positioning accuracy than rTHA cases, with significant differences in inclination (1.5° for tumour vs 3.4° for rTHA) and rotation (1.3° for tumour vs 2.4° for rTHA). The use of intraoperative navigation appeared to enhance positioning accuracy, but this did not reach statistical significance. This study demonstrates favourable CTAC positioning accuracy, with potential for improved accuracy through intraoperative navigation. Further research is needed to understand the implications of positioning accuracy on implant performance and long-term survival.

Proximal femoral defect classifications in revision total hip arthroplasty from X-rays imaging to advanced 3D imaging: a narrative review.

Femoral bone defect in hip arthroplasty revision surgery represents a complex problem, and the treatment is a challenge for orthopedic surgeons called to assess the residual bone stock in an altered anatomy and obtain stability for the new implant. Classification systems available are mostly based on X-rays two-dimensional images and lack of accuracy and reproducibility and comprehensive therapeutic algorithms. However, there is no record of any classification based on computed tomography (CT)-scan images or three-dimensional (3D) modeling modern techniques. We aimed to review the current literature around femoral defect classifications (FDCs) analyzing their different rationale basis, reliability and accuracy, and their benefit in clinical practice. Moreover, we highlighted the role of CT scan-based 3D modeling techniques in the setting of femoral bone defects and revision hip arthroplasty. A narrative review was conducted. The articles were selected from the PubMed and Scopus medical database updated to March 2023. All Level-I to IV studies in the English language were considered for inclusion. The research was performed using relevant search term items: "femoral defects", "classification", "radiographic", "revision hip arthroplasty", "CT scan" and "3D" and we included only articles that evaluated the accuracy or reliability (or both) of the different femoral bone defects classification system. Our search yielded 408 results, of which 17 were deemed highly relevant. We found seven X-ray-based classification systems which have been attempted to quantify the degree of bone loss with low to good reproducibility. The most used classification system for femoral bone defects were the AAOS and Paprosky classification, which also offers a clinical therapeutic algorithm. In 2021, the FDC interestingly showed a new simple classification system with sub-optimal reproducibility and a practical therapeutic algorithm. Despite the numerous classification system of femoral defects, none of them comprehends the use of CT scan and 3D imaging technologies. Traditional X-rays-based classification system are still widely used event if their intra-observer and inter-observer reliability is sub-optimal. 3D modeling techniques represent an important diagnostic tool that could improve the understanding of bone defects and residual bone supportive structures, allowing to elaborate new, more precise, classification systems.

Optimal reimplantation timing in two-stage exchange for periprosthetic joint infection: an observative cohort study in Asian population

BackgroundThe optimal timing for reimplantation for periprosthetic joint infection (PJI) has not been established and varies from a few weeks to several months. The aim of this study was to assess the commendable time between implant removal and reimplantation in patients who underwent two-stage exchange arthroplasty for PJI.MethodsWe retrospectively reviewed 361 patients who were treated with two-stage exchange arthroplasty for hip and knee chronic PJI at our institution between January 2000 and December 2018. Patient characteristics, comorbidities, surgical variables, microbiology data, and time to reimplantation were recorded. All patients were followed for a minimum of one year. Treatment failure was defined by Delphi criteria. Logistic regression analyses were used to calculate survival rates and adjusted odds ratios (ORs) of treatment failure.ResultsIn final analysis, 27 (7.5%) had treatment failure. Factors related to treatment failure including interim spacer exchange (OR, 3.13; confidence interval (CI), 1.04–9.09, p = 0.036), higher ESR level at reimplantation (OR, 1.85; CI, 1.05–3.57; p = 0.04), and time to reimplantation (OR, 1.00; CI, 1.003–1.005, p = 0.04). Performing revision arthroplasty surgery from 16 to 20 weeks had highest successful rate. The reimplantation over 24 weeks had a lower successful rate. However, no statistical significance in comparing each interval group.ConclusionOur study emphasized the importance of timely reimplantation in achieving successful outcomes. Factors such as ESR levels, spacer exchange, and the duration of time to reimplantation influenced the likelihood of treatment failure in two-stage exchange arthroplasty for hip and knee PJI.

Accuracy of Serological Markers, Synovial Fluid, Microbiological Culture, and Histopathological Examination for Diagnosing Periprosthetic Knee Infection.

Objective This study assessed the sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of serological tests, synovial fluid markers, microbiological tissue culture, and histopathological examination of the periprosthetic membrane in diagnosing periprosthetic knee infection. Methods This study is prospective, and it includes patients undergoing total knee arthroplasty revision surgery from November 2019 to December 2021. The analysis consisted of serological tests (erythrocyte sedimentation rate [ESR], C-reactive protein [CRP], and D-dimer), synovial fluid markers (leukocyte and polymorphonuclear cell counts), periprosthetic tissue culture, and histopathological examination of the periprosthetic membrane of all patients. Results Sixty-two patients had periprosthetic joint infection (PJI) according to the 2018 International Consensus Meeting criteria (infection group), while 22 subjects had no infection. ESR sensitivity and specificity were 83.6% and 45.4%, respectively. CRP sensitivity and specificity were 64.5% and 100%, whereas D-dimer sensitivity and specificity were 78.9% and 25%, respectively. Leukocyte count sensitivity and specificity were 75.6% and 100%, polymorphonuclear cell count sensitivity and specificity were 33% and 100%, respectively. Periprosthetic tissue culture sensitivity and specificity culture were, respectively, 77.4% and 100%. Histopathological examination sensitivity and specificity were 43.7% and 100%, respectively. Conclusions In our study, the total blood cell count in synovial fluid and microbiological cultures of periprosthetic tissues were the most accurate tests for PJI diagnosis. In contrast, polymorphonuclear cell percentage was the least accurate test for PJI diagnosis.

Patient mortality after total hip arthroplasty revision surgery

BackgroundComplications following revision total hip arthroplasty can cause significant morbidity and have a high mortality rate. Patient age and American Society of Anaesthesiologists (ASA) physical status classification system score are important determinants of mortality following revision hip arthroplasty. There is a paucity of high-quality evidence assessing the risk of mortality following revision hip arthroplasty stratified by indications of surgery. The aim of this study is to compare survival of patients undergoing revision THA for different indications. MethodsThis retrospective case series reviewed the mortality rate following revision hip surgery performed by a single surgeon between 2009 and 2016 with a minimum 2 year follow up. Kaplan Meir analysis was performed using mortality as the end point. Log rank testing was used to determine if the indication for surgery conferred a difference in survival. ResultsOne hundred and ninety-eight consecutive cases were done using a tapered modular uncemented stem in 183 patients and were followed up for a mean period of 51.8 months (range, 24–121). Sixty patients died (67 % survivorship) during the follow up period with a 5-year survival rate of 78 %. Revision surgery performed for aseptic loosening had the best survival and hemiarthroplasty had the worst and differences in survival were statistically significant (P = 0.000002). ConclusionThe indication for revision surgery is an important criterion which must be given weightage along with age, functional status of patient and ASA physical status score while planning revision surgery and counselling patients.

Implications of ageing effects on thermal and mechanical properties of PMMA-based bone cement for THA revision surgery

Loosening and infection are the main reasons for revision surgery in total hip arthroplasty (THA). Removing partially detached cemented implant components during revision surgery remains challenging and poses the risk of periprosthetic bone damage.A promising approach for a gentler removal of partially detached prostheses involves softening the PMMA-based bone cement by heating it above its glass transition temperature (TG), thus loosening the implant-cement bond. It is assumed that the TG of PMMA-based bone cement decreases in-vivo due to the gradual absorption of body fluid. Reliable data on TG are essential to develop a heat-based method for removing cemented implant components during revision surgery.The effect of water absorption was investigated in-vitro by ageing PMMA-based bone cement samples for different periods up to 56 days in both Ringer's solution (37 °C) and air (37 °C and 30% humidity). Subsequently, the TG and Vicat softening temperatures of the samples were determined by differential scanning calorimetry and Vicat tests, respectively, according to prescribed methods.Over the entire ageing period, i.e. comparing one day of ageing in air and 56 days in Ringer's solution, the Vicat softening temperature dropped by 16 °C, while the TG dropped by 10 °C for Palacos® R PMMA-based bone cement. Water absorption over time correlated significantly with the Vicat softening temperature until saturation of the PMMA-based bone cement was reached.Based on the TG and Vicat softening temperature measurements, it can be assumed that in body-aged bone cement, an optimal softening can be achieved within a temperature range of 85 °C–93 °C to loosen the bond between the PMMA-based bone cement mantle and the prosthesis stem. These findings may pave the way for a gentler removal of the implant in revision THA.

Revision of total ankle arthroplasty: Survival and medium-term functional results

BackgroundThe objective of this study was to analyze the results and survivorship of total ankle arthroplasty (TAA) revision surgery with standard (Salto Talaris®) or revision (Salto Talaris XT®) implants. MethodsBetween January 2005 and December 2017, all patients undergoing TAA revision at our hospital were included. Indications for revision, type of surgery performed, improvement in function assessed with the AOFAS score, occurrence of complications and implant survival at last follow-up were analyzed. ResultsIn the end, 25 TAA patients who had undergone revision (11 unipolar, 14 bipolar) were included. The mean follow-up time was 5.1 ± 1.9 years. At the last follow-up, function was improved compared to the preoperative AOFAS score (51.3 ± 17.5 vs. 83.5 ± 10.1; p < .001), but not plantar flexion (17.5 ± 5.7 vs. 15.4 ± 7.1; p = 0.28) or dorsal flexion (7 ± 5.6 vs. 8.3 ± 4.9; p = 0.3). Complications occurred in six patients (24 %) that led to reoperation: three infections, one lateral impingement, one implant malposition, and one hindfoot alignment disorder. At the last follow-up, implant survival was 96 %, but the probability of survival without reoperation was 78.7 ± 8.5 % at 4 years. ConclusionTAA revision by arthroplasty is feasible, produces good functional results in the medium term, but has a high risk of complications. The challenge of revision TAA is managing the loss of bone stock and anchoring the new implants.

Custom triflange acetabular components for large acetabular defect reconstruction in revision total hip arthroplasty: a systematic review and meta-analysis on 1218 patients.

This is a systematic review and meta(regression) analysis to assess the performance of custom triflange acetabular components (CTAC) in total hip arthroplasty (THA) revision surgery. Implant-related complications, failure rate, functional outcomes and implant and surgical technique-related predictors for outcome were assessed. This systematic review was performed according to PRISMA guidelines and registered with PROSPERO (2020 CRD42020209700). PubMed, Embase, Web of Science, COCHRANE Library and Emcare were searched. Studies on Paprosky type 3A and 3B or AAOS type 3 and 4 acetabular defects with a minimum follow-up of 12 months and cohorts > 10 patients were included. Thirty-three studies were eligible for inclusion (n = 1235 hips, 1218 patients). The methodological quality of the studies was moderate (AQUILA: 7.4/11 points). Considerable heterogeneity was observed in terms of complications, re-operations and implant failure reporting. The total incidence of implant-related complications was 24%. The incidence of re-operation for any reason was 15%, and the implant failure rate was 12% at a mean of 46.9 months and the post-operative Harris Hip Score improved by a mean of 40 points. Several predictors for outcome were found, such as implant generation, follow-up length and study start date. The use of CTAC in revision THA has satisfactory complication and implant failure rates. The CTAC technique improves post-operative clinical outcomes and the meta-regression analysis showed that there is a clear association between improvements in the CTAC performance and the evolvement of this technique over time.

Investigating the correlation between hip abductor muscle strength and width in anteroposterior pelvic radiographs in hip revision candidates following previous total hip arthroplasty: a cross-sectional study.

This cross-sectional study included the patients underwent hip arthroplasty and were candidates for revision surgery. The diameter of the hip abductor muscles on the affected and unaffected sides were calculated based on plain radiography. Patients were also clinically examined and their abductor muscle strength on both sides were determined based on Medical Research Council Manual Muscle Testing scale. A total of 51 patients were included in the study and after exiting 20 patients; finally 31 patients' data were analyzed. Based on results there was a significant correlation between the ratios of muscle strength and muscle diameter in affected side to unaffected side (r=0.517, P=0.003). As indicated in Table 3, such significant association was revealed in men (r=0.719, P=0.001), but not in women (r=-0.092, P=0.754). Also, this relationship was found to be significant in patients older than 60 years (r=0.529, P=0.011), not in the younger. In patients undergoing total hip arthroplasty revision surgery, there is a strong association between the ratio of strength and diameter of the abductor muscles in the affected side to the unaffected side especially in men and older ages.

Effectiveness and safety of a cement-on-cement removal system for hip and knee arthroplasty revision surgery.

Cement removal during hip or knee arthroplasty revision is challenging and not exempt of complications. Cement-on-cement procedure is among techniques developed to safe removal of cement from bone, and it could be a realistic solution. This cement-on-cement devices can provide advantages in removing bone cement during hip and knee arthroplasty septic and non-septic revision surgeries, and can be regarded as an effective and safe alternative. We present our experience using the cement-on-cement technique in 34 cases between 2010 and 2021, including revision surgeries for 20 knee and 14 hip arthroplasties. In 3 out of 34 cases the technique failed, with a success of 91%. Mean surgical time was 2.77 (SD 0.93) hours and blood transfusion was required in 23 cases. Success was achieved in every aseptic case. Of all patients, 60% were septic cases. Infection was considered to be eradicated in 70% (14/20) of patients with a septic revision. Cement-on-cement is a safe and effective alternative for cement removal during hip and knee arthroplasty revision. Level of evidence: III, retrospective case series.

FeMn and FeMnAg biodegradable alloys: An in vitro and in vivo investigation

Iron-based biodegradable metal bone graft substitutes are in their infancy but promise to fill bone defects that arise after incidents such as trauma and revision arthroplasty surgery. Before clinical use however, a better understanding of their in vivo biodegradability, potential cytotoxicity and biocompatibility is required. In addition, these implants must ideally be able to resist infection, a complication of any implant surgery. In this study there was significant in vitro cytotoxicity caused by pure Fe, FeMn, FeMn1Ag and FeMn5Ag on both human foetal osteoblast (hFOB) and mouse pre-osteoblast (MC3T3-E1) cell lines. In vivo experiments on the other hand showed no signs of ill-effect on GAERS rats with the implanted FeMn, FeMn1Ag and FeMn5Ag pins being removed largely uncorroded. All Fe-alloys showed anti-bacterial performance but most markedly so in the Ag-containing alloys, there is significant bacterial resistance in vitro.

Detection of Prosthetic Loosening in Hip and Knee Arthroplasty Using Machine Learning: A Systematic Review and Meta-Analysis.

Background: prosthetic loosening after hip and knee arthroplasty is one of the most common causes of joint arthroplasty failure and revision surgery. Diagnosis of prosthetic loosening is a difficult problem and, in many cases, loosening is not clearly diagnosed until accurately confirmed during surgery. The purpose of this study is to conduct a systematic review and meta-analysis to demonstrate the analysis and performance of machine learning in diagnosing prosthetic loosening after total hip arthroplasty (THA) and total knee arthroplasty (TKA). Materials and Methods: three comprehensive databases, including MEDLINE, EMBASE, and the Cochrane Library, were searched for studies that evaluated the detection accuracy of loosening around arthroplasty implants using machine learning. Data extraction, risk of bias assessment, and meta-analysis were performed. Results: five studies were included in the meta-analysis. All studies were retrospective studies. In total, data from 2013 patients with 3236 images were assessed; these data involved 2442 cases (75.5%) with THAs and 794 cases (24.5%) with TKAs. The most common and best-performing machine learning algorithm was DenseNet. In one study, a novel stacking approach using a random forest showed similar performance to DenseNet. The pooled sensitivity across studies was 0.92 (95% CI 0.84-0.97), the pooled specificity was 0.95 (95% CI 0.93-0.96), and the pooled diagnostic odds ratio was 194.09 (95% CI 61.60-611.57). The I2 statistics for sensitivity and specificity were 96% and 62%, respectively, showing that there was significant heterogeneity. The summary receiver operating characteristics curve indicated the sensitivity and specificity, as did the prediction regions, with an AUC of 0.9853. Conclusions: the performance of machine learning using plain radiography showed promising results with good accuracy, sensitivity, and specificity in the detection of loosening around THAs and TKAs. Machine learning can be incorporated into prosthetic loosening screening programs.

Goal-directed fluid therapy using uncalibrated pulse contour analysis and balanced crystalloid solutions during hip revision arthroplasty: a quality implementation project

BackgroundTo implement a goal-directed fluid therapy (GDFT) protocol using crystalloids in hip revision arthroplasty surgery within a quality management project at a tertiary hospital using a monocentric, prospective observational study.MethodsAdult patients scheduled for elective hip revision arthroplasty surgery were screened for inclusion in this prospective study. Intraoperatively stroke volume (SV) was optimized within a previously published protocol using uncalibrated pulse contour analysis and balanced crystalloids. Quality of perioperative GDFT was assessed by protocol adherence, SV increase as well as the rate of perioperative complications. Findings were then compared to two different historical groups of a former trial: one receiving GDFT with colloids (prospective colloid group) and one standard fluid therapy (retrospective control group) throughout surgery. Statistical analysis constitutes exploratory data analyses and results are expressed as median with 25th and 75th percentiles, absolute and relative frequencies, and complication rates are further given with 95% confidence intervals for proportions using the normal approximation without continuity correction.ResultsSixty-six patients underwent GDFT using balanced crystalloids and were compared to 130 patients with GDFT using balanced colloids and 130 controls without GDFT fluid resuscitation. There was a comparable increase in SV (crystalloids: 65 (54–74 ml; colloids: 67.5 (60–75.25 ml) and total volume infused (crystalloids: 2575 (2000–4210) ml; colloids: 2435 (1760–3480) ml; and controls: 2210 (1658–3000) ml). Overall perioperative complications rates were similar (42.4% (95%CI 30.3–55.2%) for crystalloids and 49.2% (95%CI 40.4–58.1%) for colloids and lower compared to controls: 66.9% (95%CI 58.1–74.9)). Interestingly, a reduced number of hemorrhagic complications was observed within crystalloids: 30% (95%CI 19.6–42.9); colloids: 43% (95%CI 34.4–52.0); and controls: 62% (95%CI 52.6–69.9). There were no differences in the rate of admission to the post-anesthesia care unit or intensive care unit as well as the length of stay.ConclusionsPerioperative fluid management using a GDFT protocol with crystalloids in hip revision arthroplasty surgery was successfully implemented in daily clinical routine. Perioperative complications rates were reduced compared to a previous management without GDFT and comparable when using colloids.Trial registration: ClinicalTrials.gov identifier: NCT01753050.

STIMULAN® IN ORTHOPAEDIC SURGERY: TECHNIQUE AND INDICATIONS FOR USE

Infections represent a devastating complication in orthopedic and traumatological surgery, with high rates of morbidity and mortality. An early intervention is essential, and it includes a radical surgical approach supported by targeted intravenous antimicrobial therapy. The availability of parenteral antibiotics at the site of infection is usually poor, so it is crucial to maximize local antibiotic concentration using local carriers. Our work aims to describe the uses of one of these systems, Stimulan®, for the management and prevention of infections at our Institution.Analysing the reported uses of Stimulan®, we identified two major groups: bone substitute and carrier material for local antibiotic therapy. The first group includes its application as a filler of dead spaces within bone or soft tissues resulting from traumatic events or previous surgery. The second group comprehends the use of Stimulan® for the treatment of osteomyelitis, post-traumatic septic events, periprosthetic joint infections, arthroplasty revision surgery, prevention in open fractures, surgery of the diabetic foot, oncological surgery and for all those patients susceptible to a high risk of infection.We used Stimulan® in several complex clinical situations: in PJIs, in DAPRI procedure and both during the first and the second stage of a 2-stage revision surgery; furthermore, we started to exploit this antibiotic carrier also in prophylaxis of surgical site infections, as it happens in open fractures, and when a surgical site remediation is required, like in osteomyelitis following ORIF. Stimulan® is an extremely versatile and polyhedric material, available in the form of beads or paste, and can be mixed to a very broad range of antibiotics to better adapt to different bacteria and their antibiograms, and to surgeon's needs. These properties make it a very useful adjuvant for the management of complex cases of infection, and for their prevention, as well.