Joint Replacement Research Articles

Total elbow allograft augmented with vascularized periosteal grafts for salvage of a failed distal humeral joint replacement for Ewing sarcoma reconstruction.

Vascularized periosteal grafts have been used to promote bone union in massive bone defects. We present a child with a failed distal humeral joint replacement for Ewing sarcoma reconstruction, successfully treated with a total elbow allograft augmented by vascularized periosteal grafts.Level of evidence: V.

Personalized Stem Length Optimization in Hip Replacement: A Microscopic Perspective on Bone-Implant Interaction.

Total hip replacement (THR) surgery involves the removal of necrotic tissue and the replacement of the natural joint with an artificial hip joint. The demand for THR is increasing due to population aging and prolonged life expectancies. However, the uniform length and shape of artificial hip joints can cause stress shielding, leading to implant loosening and femoral fractures. These issues arise because these designs fail to account for the unique anatomical and biomechanical characteristics of individual patients. Therefore, this study proposes and validates a method to optimize stem length by considering bone microstructure and daily load. The results demonstrated that the optimal stem length varies with loading conditions and significantly reduces stress in the cortical bone while maintaining an appropriate strain energy in the cancellous bone, thereby preventing bone loss. These findings underscore the importance of patient-specific stem design for improving implant stability and clinical outcomes.

Feasibility of mNGS in joint replacement patients exhibiting elevated ESR and CRP levels without an underlying diagnosis

ObjectiveThe aim of this study is to investigate the viability of performing initial artificial joint replacement surgery in patients presenting with unexplained elevations in erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels.MethodsA cohort of 22 patients, comprising 11 cases each for knee and hip joint replacements, who underwent initial artificial joint replacement surgery between November 2020 and January 2022, was recruited. All patients exhibited elevated levels of ESR and CRP prior to surgery, the etiology of which remained undetermined. Intraoperatively, joint effusion and periarticular tissues were preserved for subsequent bacterial culture and metagenomic next-generation sequencing (mNGS). Postoperatively, a combination of intravenous and local antibiotics was administered for anti-infective management. In cases where bacterial culture and/or mNGS yielded positive results, patients were diagnosed with periprosthetic joint infections (PJI) and underwent one-stage revision; conversely, negative findings led to the discontinuation of intravenous and local antibiotics therapy.ResultsAmong the cohort of 22 patients, bacterial cultures yielded negative results, while mNGS identified bacterial infection in 14 patients (63.63%), viral infection in 1 patient (4.55%), and yielded negative results in 7 patients (31.82%). All surgical incisions achieved per primam. Subsequent follow-up assessments conducted for more than 1 year postoperatively revealed absence of PJI among the patients, all of whom exhibited satisfactory progress in their rehabilitation exercises. Notably, the Knee Society Score (KSS) for knee joint patients significantly improved from a preoperative mean of 48.7 ± 3.3 points to 84.3 ± 2.2 points postoperatively, whereas the Harris Hip Score for hip joint patients increased significantly from preoperative mean of 50.6 ± 3.6 points to 87.1 ± 1.6 points (P < 0.01).ConclusionIn cases where patients present with unexplained elevations in ESR and CRP levels, primary artificial joint replacement can be undertaken following a one-stage revision approach for PJI.

Clinically applicable optimized periprosthetic joint infection diagnosis via AI based pathology

Periprosthetic joint infection (PJI) is a severe complication after joint replacement surgery that demands precise diagnosis for effective treatment. We enhanced PJI diagnostic accuracy through three steps: (1) developing a self-supervised PJI model with DINO v2 to create a large dataset; (2) comparing multiple intelligent models to identify the best one; and (3) using the optimal model for visual analysis to refine diagnostic practices. The self-supervised model generated 27,724 training samples and achieved a perfect AUC of 1, indicating flawless case differentiation. EfficientNet v2-S outperformed CAMEL2 at the image level, while CAMEL2 was superior at the patient level. By using the weakly supervised PJI model to adjust diagnostic criteria, we reduced the required high-power field diagnoses per slide from five to three. These findings demonstrate AI’s potential to improve the accuracy and standardization of PJI pathology and have significant implications for infectious disease diagnostics.

Systematic Review and Meta-Analysis of Total Elbow Arthroplasty in Outpatient Versus Inpatient Settings.

Total joint arthroplasties, including total elbow arthroplasty (TEA), are growing in number and shifting towarda younger age group. These procedures are also moving more towardthe outpatient setting compared to previous years. We are conducting this study to update and summarize the current knowledge about the outcomes of TEA in outpatient versus inpatient settings.We conducted a systematic review and meta-analysis using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework to compare TEA outcomes in outpatient versus inpatient settings. Electronic database searches were performed using PubMed, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, and Google Scholar. Previous studies deemed eligible for this study focused on inpatient cohortsand outpatient cohortsor compared inpatient and outpatient cohorts receiving TEA. Alldata used was obtained from the studiesthat were included.Three studies were deemed eligible and included a total of 1,634 patients, with 1,048 being inpatient and 586 being outpatient. There was a significant increase in total (any) complication rate (log of odds ratio (lnOR): 1.02, 95% CI: 0.35 to 1.68), adverse discharge (lnOR: 1.07, 95% CI: 0.22 to 1.92), and surgical site infection (lnOR: 0.88, 95% CI: 0.05 to 1.71) in the inpatient setting compared to the outpatient setting. There was no significant difference between outpatient and inpatient settings in regard to readmissions (lnOR: 0.85, 95% CI: -0.95 to 2.66), urinary tract infections (UTI)/renal complications (lnOR: 0.04, 95% CI: -0.09 to 0.17), pneumonia/respiratory failure (lnOR: 0.61, 95% CI: -0.29 to 1.51), deep vein thrombosis (DVT)/pulmonary embolism (lnOR: 0.07, 95% CI: -1.31 to 1.44), sepsis (lnOR: 0.86, 95% CI: -0.50 to 2.21), and wound dehiscence (lnOR: 0.55, 95% CI: -0.58 to 1.68).Our results reveal that with careful patient selection, current surgical techniques, and pain control methods, TEA may be performed in the outpatient setting with less risk of complications and lower financial burden compared to inpatient TEA.

Functional Outcomes of Robotic-Assisted Total Knee Arthroplasty in Severe Varus Deformities of the Knee in the Indian Population.

Correction of severe coronal plane deformities while performing a total knee arthroplasty (TKA) is challenging. The use of functional alignment (FA) strategy along with image-based robotic technology during TKA makes it possible to restore a patient's constitutional alignment with minimal or no soft tissue release. The present study aims to report the functional outcomes of robotic-assisted TKA in Indian patients with severe varus deformity. This retrospective study included 82 primary TKA performed by a single senior arthroplasty surgeon from January 2022 to December 2022. The Visual Analogue Score for Pain (VAS-P) and the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR) were used to assess functional outcomes. A comparison between mild and severe varus deformities was done using Student's t-test. The mean age was 66.35 ± 9.21 years. There were 79 (96.34%) knees with a mean preoperative varus hip-knee-ankleangle (HKA)of 12.85° ± 6.03° (range = 177°-148°). Postoperative limb alignment was achieved in the range of HKA 174° to 180°, with mean HKA being 175.78° ± 1.35°. The VAS-P improved significantly from a mean of 7.87 ± 0.81 preoperatively to 1.96 ± 1.43 at 18 months. KOOS-JR improved from 41.22 ± 7.6 preoperatively to 88.44 ± 8.23 at 18 months. A total of 73(89.02%) cases achieved the minimal clinically important difference (MCID) for VAS-P and 77(93.9%) cases achieved the MCID for KOOS-JR in our study. Functional outcomes were comparable among the mild (<10°) and severe (>10°) varus deformity cases at 18 months follow-up (p-value > 0.05). There was a significant difference in bone resection from the medial tibial and medial distal femoral condyle (p-value < 0.05) with less bone resected in the severe varus group. The amount of bone resected from the lateral tibial, distal lateral femoral, andposterior femoral condyles was comparable among the two groups (p-value > 0.05). FA was more bone conserving even in severe varus-deformed knees when compared to mechanical alignment (MA). The use of FA with robotic assistance to correct severe varus deformities in TKA showed a significant reduction in VAS-P scores and an improvement in KOOS-JR scores. The functional outcomes were comparable with TKA in mild varus deformities. FA helps in preserving bone from the lateral tibial condyle and distal femur.

How Much Does Prosthetic Joint Infection and Its Successful Treatment Affect Patient-reported Quality of Life?

Uncomplicated joint replacement improves pain and other patient-reported outcome measures (PROMs) such as joint function scores and quality-of-life measures. However, the overall impact of periprosthetic joint infection (PJI) and its successful treatment on PROMs is poorly defined. In this study, we describe quality-of-life scores using the 12-item Short Form survey, version 2 (SF-12v2), collected as part of a large, prospective, observational study of PJI. (1) Do patients with newly diagnosed PJI have lower quality-of-life scores than the general age-matched population? (2) Are lower quality-of-life scores for patients with PJI sustained for ≥ 12 months? (3) What factors are associated with a good functional outcome at 12 months, defined by achieving a physical component summary (PCS) score of > 50 on the SF-12v2 (that is, above the age-adjusted population mean) or an increase of > 8.9 or more from baseline? The PIANO (Prosthetic joint Infection in Australia and New Zealand, Observational study) cohort was a prospective, longitudinal, multicenter cohort study of 783 patients with newly diagnosed PJI recruited across 27 centers between July 2014 and December 2017. All participants were followed for 2 years. SF-12v2 scores were collected at diagnosis (baseline) and 3, 12, and 24 months after diagnosis. Treatment success was defined as being alive with no clinical or microbiological evidence of infection and no ongoing use of antibiotics for the index joint. After exclusion of 6.6% (52) who had died, 4.2% (33) with PJI of joints other than hips and knees, and those with incomplete data sets (200 [25.5%]), 498 patients had complete SF-12v2 data sets available. At baseline, the median (IQR) PCS score was 37 (30 to 46), which increased to 41 (34 to 49; p < 0.001) at 12 months. Both measures were lower than those for the general age-matched population norm. There was no further improvement in PCS scores between 12 and 24 months. By contrast, the median (IQR) mental component summary score of the SF-12v2 was similar to age-adjusted population norms (48 [37 to 57]) at baseline. Only 40% of patients with PJI achieved a good functional outcome at 12 months. After adjustment for other factors, treatment success of PJI increased the odds of a good functional outcome by 67% (95% CI 11% to 154%; p = 0.02). PJIs have a large effect on the PCS score of the SF-12v2 quality-of-life measure at baseline, which is sustained for at least 2 years. Successful treatment of PJI increases the likelihood of a good functional outcome. These data can be used to set expectations for patients presenting with PJI and can be used to inform future clinical studies in which quality-of-life measures are incorporated into clinical endpoints. Level II, therapeutic study.

The Fragility of Statistical Significance in the Use of Aspirin in Prevention of Venous Thromboembolism Events Following Total Joint Arthroplasty: Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Background/Objectives: Comparative studies often use the p value to convey statistical significance, but fragility indices (FI) and fragility quotients (FQ) may better signify statistical strength. The use of aspirin as venous thromboembolism (VTE) chemoprophylaxis following elective arthroplasty has been debated between the orthopedic and cardiac fields. The purpose of this study was to apply both the FI and FQ to evaluate the degree of statistical fragility in the total joint arthroplasty (TJA) literature regarding aspirin (ASA) use for VTE prevention. Methods: We performed a systematic search for TJA clinical trials from 2004 to 2023 reporting comparisons between ASA and other chemoprophylaxis methods for VTE. The FI of each outcome was calculated through reversal of a single outcome event until significance was reversed. The FQ was calculated by dividing each fragility index by study sample size and interquartile range (IQR) was calculated. SPSS Meta-analysis function was used to calculate the Mean Effect Size Estimate and 95% Confidence Intervals for each outcome. Results: Of 245 articles screened, 39 met search criteria, with 10 RCTs included for analysis (n = 11,481 patients). There were 38 outcome events reported, with three significant (p < 0.05) outcomes and 35 non-significant (p > 0.05) outcomes identified. The overall FI and FQ for all 38 outcomes were 6 (IQR: 5-7) and 0.059 (IQR: 0.044-0.064), respectively. Seven studies (70%) reported a loss-to-follow-up (LTF) greater than the overall FI. There was no increased risk of DVT, PE, or mortality with use of ASA (all p > 0.2). Conclusions: Despite showing non-inferiority in preventing venous thromboembolic events in TJA overall, the highest-level peer-reviewed literature concerning aspirin use following total joint arthroplasty is considered statistically fragile due to high loss-to-follow-up. In addition to the reporting of the p value, the fragility index and quotient can further provide insight into the strength and trustworthiness of outcome measures.

Ti3C2Tx-UHMWPE Nanocomposites-Towards an Enhanced Wear-Resistance of Biomedical Implants.

There is an urgent need to enhance the mechanical and biotribological performance of polymeric materials utilized in biomedical devices such as load-bearing artificial joints, notably ultrahigh molecular weight polyethylene (UHMWPE). While two-dimensional (2D) materials like graphene, graphene oxide (GO), reduced GO, or hexagonal boron nitride (h-BN) have shown promise as reinforcement phases in polymer matrix composites (PMCs), the potential of MXenes, known for their chemical inertness, mechanical robustness, and wear-resistance, remains largely unexplored in biotribology. This study aims to address this gap by fabricating Ti3C2Tx-UHMWPE nanocomposites using compression molding. Primary objectives include enhancements in mechanical properties, biocompatibility, and biotribological performance, particularly in terms of friction and wear resistance in cobalt chromium alloy pin-on-UHMWPE disk experiments lubricated by artificial synovial fluid. Thereby, no substantial changes in the indentation hardness or the elastic modulus are observed, while the analysis of the resulting wettability and surface tension as well as indirect and direct invitro evaluation do not point towards cytotoxicity. Most importantly, Ti3C2Tx-reinforced PMCs substantially reduce friction and wear by up to 19% and 44%, respectively, which was attributed to the formation of an easy-to-shear transfer film.

Surgical Management of Early Metacarpophalangeal Joint Silicone Implant Fracture in Patient With Rheumatoid Arthritis

Introduction: Metacarpophalangeal (MCP) joint arthroplasty is a common treatment modality to correct ulnar drift, pain, and functional deficits in patients with rheumatoid arthritis, an autoimmune condition targeting the synovium of joints. While silicone MCP joint implants are susceptible to revision in the long term, there is a lack of literature discussing their early breakage. The present case illustrates silicone implant fracture only 10 weeks after MCP arthroplasty—the first instance in the literature to the authors’ knowledge. Materials and Methods: The patient is a 64-year-old female with stage 4 rheumatoid arthritis who underwent right index and middle finger MCP joint arthroplasties using 0-degree silicone implants, radial sagittal band imbrication on these digits, and right ring and small finger extensor tendon centralization at the MCP joint. Results: During the 10th postoperative week, the patient presented with atraumatic middle finger pain and ulnar deviation. Imaging revealed a right middle finger MCP implant fracture at the distal stem, which underwent successful revision using a 30-degree flexed implant and index and middle extensor tendon centralization. Discussion: Nineteen months after revision surgery, the patient continues to have no pain and an improved range of motion. Ultimately, we are hopeful that the flexed silicone implant will last the patient's lifetime.

Bone allograft impregnated with tobramycin and vancomycin delivers antibiotics in high concentrations for prophylaxis against bacteria commonly associated with prosthetic joint infections.

Local delivery of antibiotics as prophylaxis for prosthetic joint infections (PJIs) is frequently used during total hip replacement surgery. Morselized bone allograft impregnated with vancomycin and tobramycin (TobraVanc) could provide effective prophylaxis against bacteria commonly associated with PJIs. In this study, the concentrations of antibiotics released by bone allograft impregnated with TobraVanc were determined by using an in vitro bioassay system entailing measuring inhibition zone diameters caused by antibiotic-impregnated bone chips cast in agar against standard curves. The concentrations were determined in samples of TobraVanc-impregnated bone graft taken before and after the application of the bone graft in the patients undergoing acetabular revision surgery. Antibiotic-impregnated bone grafts, sampled prior to application in the patient, delivered antibiotics in the concentration ranges of 730-9,800 mg/L for tobramycin and 1,300-11,000 mg/L for vancomycin. Samples taken after application in the patient released lower concentrations of tobramycin (490-1,900 mg/L; P < 0.01) and vancomycin (3,000-5,100 mg/L; P < 0.05); however, these concentrations remained well above the tobramycin minimum inhibitory concentrations (MICs) for investigated, highly tobramycin-resistant Staphylococcus epidermidis strains (MICs > 256 mg/L). At the tested concentrations, bone graft material mixed with TobraVanc delivered antibiotics in potent concentrations above the MICs for bacteria causing PJIs. Clinical trials are needed to evaluate the efficacy and risk of TobraVanc-impregnated bone graft as a prophylactic agent for patients undergoing hip replacement surgery.IMPORTANCEAntibiotic prophylaxis is the cornerstone of successful joint replacement surgery, reducing the risk for the dreaded complication of prosthetic joint infection (PJI) to roughly 0.5%-2% in standard total hip replacement (THR). In addition to systemic antibiotics, antibiotics added locally have the potential to reduce the PJI risk even further, because of the high concentrations that can be achieved in the joint with limited risk for systemic toxicity. The results in the current study show that bone chips impregnated with a combination of tobramycin and vancomycin (TobraVanc) release antibiotics in concentrations that are potent against common bacteria causing PJIs. Especially in high-risk patients, our results support the prophylactic use of TobraVanc in hip replacement surgery requiring the use of a bone graft. A clinical study testing the efficacy of TobraVanc-impregnated bone graft in reducing the incidence of PJI in hip replacement surgery is currently ongoing (EudraCT: 2021-001708-14).

Risk assessment model used to predict discharge care after total hip and total knee arthroplasty: A population-based study

BackgroundTransfer to a post-acute care facility or hospital readmission after total joint arthroplasty represent additional costs and increased surgical and health care resource utilization. Accurate prediction of post-acute care factors could help providers to plan the patient's discharge destination and have a positive impact on postoperative outcomes and readmission rates. ObjectiveTo develop a risk assessment model to predict discharge care after total hip arthroplasty (THA) and total knee arthroplasty (TKA). DesignA retrospective longitudinal observational study. Settingsand participants: This study included 209 patients who underwent primary unilateral THA or TKA at a major academic medical center in Switzerland from January 2018 to December 2019. MethodsA collection of computerized- and paper-recorded data identified the discharge destination, socio-demographic factors, comorbidities, and other factors related to the patient. Univariate and multivariate analyses were performed to describe the predictors of post-surgical discharge destinations. ResultsThe characteristics associated with post-acute care after primary unilateral THA or TKA were the absence of a caregiver, advanced age, female gender, presence of walking aids, high ASA score, and comorbidity severity. A prediction model demonstrated that these six characteristics were associated 52 % with discharge to a post-acute care destination. ConclusionsThis study allowed us to identify predictors of discharge to a post-surgical destination. Predictive models can be efficiently used to better predict which patients are predisposed to post-acute care after hospital discharge. Further studies are needed to determine the optimal criteria for different destinations.

Clinical and Functional Outcomes of Knee Arthrodesis by Charnley's External Fixator.

Background Knee arthrodesis was originally developed to manage severe joint infections such as tuberculosis before the advent of antibiotics and joint replacement techniques. The procedure aims to eliminate pain and infection by stabilizing the knee joint through bone fusion. Knee arthrodesis remains essential for cases where total knee arthroplasty is not feasible, such as in patients with severe bone loss, chronic infections, or failed knee replacements. Many studies have demonstrated fusion by external fixators because infection is the most common indication of this procedure. We studied knee arthrodesis using Charnley's compression clamps which are easy to apply and economical. Methodology A prospective observational study was conducted on 15 patients for 18 months. Patients with an infection in the knee joint (septic or tuberculous), failed total joint arthroplasty, failed fracture fixation around the knee joint, and neuropathic joints were included in the study. Patients were evaluated using the pre and postoperative Knee Society Score and Knee Society Score (Functional). Results In the study, 80% of the patients were males. Septic arthritis and tuberculosis were common indications for the surgery. More than 70% of the patients were previously operated on the same knee joint. The duration of the fixator ranged from 32 weeks to 39 weeks (7.47 months to 9.1 months) with an average of 35.73 weeks (8.34 months). The final follow-up period ranged from 9.5 to 18 months with an average of 14.1 months. The knee score ranged preoperatively from 5 to 22 (average = 16.2) and improved postoperatively ranging from 50-56 (average = 54). The functional score ranged preoperatively from 40 to 50 (average = 43.60) and improved postoperatively ranging from 80 to 100 (average = 89.66). Conclusions The fusion by Charnley's external clamps is easy, cost-effective, and comfortable for the patients. The complications are relatively fewer and the success rate of the fusion is higher with this treatment method.

A phase III study to evaluate the long-term safety and efficacy of fasinumab in patients with pain due to osteoarthritis of the knee or hip

BackgroundPain associated with osteoarthritis (OA) is frequently disabling; treatments are often ineffective or intolerable. Fasinumab selectively inhibits nerve-growth factor and has shown efficacy for the management of OA pain. MethodsIn this randomized, double-blind, phase III safety study, patients with moderate-to-severe OA pain and history of inadequate pain relief received placebo or fasinumab (at 1, 3, 6, and 9 ​mg every 4 weeks [Q4W] and 1 and 6 ​mg every 8 weeks [Q8W] for 52 weeks). Primary safety endpoints included adverse events, adjudicated arthropathies (AAs), and joint replacements (JRs). Co-primary endpoints of an efficacy sub-study were change in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and physical function scores. During the study, higher fasinumab doses were discontinued for safety; 1 ​mg doses continued. ResultsOf 13,945 patients screened, 5331 were randomized; 1074 were included in the efficacy sub-study. AAs and JRs occurred in all groups. Increased severity of disease at baseline was associated with higher rates of AAs and JRs. A dose-dependent risk of AA or JR was observed for fasinumab; in the 1 ​mg groups, only a small percentage of patients with JR had prior AA. Fasinumab significantly improved WOMAC pain and physical function scores compared with placebo; least squares mean differences versus placebo were −1.22 and ​−1.20 for 1 ​mg Q4W and −0.73 and ​−0.74 for 1 ​mg Q8W, respectively (P<0.001). ConclusionAAs and JRs showed a dose relationship to fasinumab and were associated with baseline OA status. Fasinumab achieved statistically significant improvements in WOMAC pain and physical function scores compared with placebo.

Effect of non-contact induction heating on HA coatings and bone cement, an ex vivo study

Background Prosthetic joint infection is a serious complication that can arise after total joint replacement surgery. When bacteria colonise an orthopaedic implant, they form biofilms that protect them from their environment, making them difficult to remove. Treatment is further complicated by a global rise of antimicrobial resistance. These protective mechanisms make treatment of prosthetic joint infection increasingly complex. Non-contact induction heating is an upcoming technology that uses heat to eradicate bacteria that are present on the surface of metallic implants. This study aims to provide insight into the feasibility of using non-contact induction heating on metallic implants that are in direct contact with other biomaterials, such as coatings composed of hydroxyapatite and bone cement composed of poly (methyl methacrylate) (PMMA). Methods Characterisation of hydroxyapatite coatings and adhesion strength tests were conducted according to standards set by the International Organisation for Standardisation (ISO 13779-2). The fixation strength of acrylic bone cement was tested according to an adapted method from ISO. Results It was found that non-contact induction heating did not significantly affect the adhesion strength of hydroxyapatite coatings. In contrast to hydroxyapatite coatings, acrylic bone cement softened temporarily as the temperature exceeded the glass transition temperature (83.38 ± 10.88°C). However, the induction heating temperature had no significant effect on the fixation strength after the cement was allowed to cool down. Conclusion This study shows the feasibility of using non-contact induction heating up to 80°C when bone cement or ceramic coatings are present in contact with infected metallic implants.

Economic burden of knee joint replacement in Iran

BackgroundThe knee is the most commonly afflicted weight-bearing joint. Osteoarthritis of the knee is regarded as one of the most commonly diagnosed causes of disability in the elderly. Knee joint replacement can be regarded as a final solution for Osteoarthritis of the knee in which the joint is worn out, accompanied by clinical symptoms such as pain, deformity, and limited movement.Aimthis study sought to estimate the economic burden of knee joint replacement procedures carried out in Iran.MethodThis cross-sectional descriptive study utilized the Incidence-based approach to assess the economic burden of knee joint replacement surgeries conducted in Iran during 2022, estimating the costs of the disease from a societal perspective. The sampling method employed was random sampling, and the sample size consisted of 300 patients. Direct costs were calculated employing the top-down approach, while indirect costs were estimated using the human capital approach. Microsoft Excel was employed for data analysis.ResultThe average direct medical costs of the knee replacement procedure per patient were $10,076.87 and $13,099.93 in the public and private sectors, respectively. The average direct non-medical costs of knee joint replacement surgery are $1123.64, with companion costs constituting most of the direct non-medical costs. Finally, the economic burden of the knee joint replacement surgery was estimated at $67340417.28.ConclusionDespite insurance coverage, knee joint replacement surgery in Iran incurs substantial costs. With the anticipated rise in the elderly population, the frequency of these procedures is expected to increase, amplifying the economic burden on the Iranian public.

Results of endoprosthesis of the elbow joint in patients with tumors of forming it bones

Background. The use of both individual and modular oncological endoprostheses of the elbow joint is possible with primary and secondary (metastatic) tumor lesions of the bones forming it. The purpose of the study was to assess the effectiveness of restoring the function of the elbow joint and the upper limb and improving the quality of life of the patient after endoprosthesis of the elbow joint due to tumors of the bones forming it. ­Material and methods. The results of the treatment of 14 patients who underwent endoprosthesis of the elbow joint due to tumors of the bones forming it were evaluated. Endoprosthesis was performed in 9 (64.3 %) subjects with primary bone tumors and in 5 (35.7 %) patients with metastatic tumors. Reconstruction of the elbow joint was performed with individual oncological endoprostheses in 10 (71.4 %) subjects and modular oncological endoprostheses in 4 (28.6 %) ones. Reconstruction was primary in 12 (85.7 %) patients and secondary in 2 (14.3 %) ones. Results. Du­ring follow-up, 4 (28.6 %) patients died from the progression of the main disease with an ave­rage follow-up period of 24.8 ± 11.9 months, the other 10 (71.4 %) were alive, with an average follow-up period of 80.8 ± 10.3 months. In the early postoperative period, the following complications were observed: neuropathy of the ulnar nerve in 1 (7.1 %) patient. In the late postoperative period, 1 (7.1 %) patient had an infectious complication after 14 months. 1 (7.1 %) subject developed aseptic loose­ning of the humeral leg of the endoprosthesis 12 months after endoprosthesis. In 1 (7.1 %) subjects with a metastatic tumor, local recurrence of the tumor was observed 9 months after surgery. Mean MEPS and MSTS functional scores were 80 and 72 %, respectively. The patients’ quality of life (according to the EORTQ-QLQ-С30 questionnaire) increased from 40 points in the preoperative period to 84 points after elbow joint replacement. Conclusions. Endoprosthesis of the elbow joint in the schemes of complex and combined treatment of primary and metastatic tumors of the bones forming it helps to improve the quality of life of this contingent of patients.

Clinical and Radiographic Outcomes With Minimum 2-Year Follow-up and Sub-Analysis of Navigation vs Non-Navigation for Hip Resurfacing.

The purpose of this study was to report the short-term clinical outcomes of hip resurfacing with navigation and the impact on accuracy of acetabular implant placement in both the frontal and sagittal planes. Data were retrospectively analyzed for patients who received hip resurfacing between 2010 and 2021. Eligible patients had postoperative radiographs and completed a minimum 2-year follow-up questionnaire for the following patient-reported outcomes: modified Harris Hip Score (mHHS), Harris Hip Score (HHS), Forgotten Joint Score (FJS), visual analog scale (VAS) score, satisfaction, and Hip Disability and Osteoarthritis Outcome Score, Joint Replacement (HOOS-JR). Hips were propensity matched in a 1:1 ratio based on the use of navigation, age, and body mass index. The percentage of hips that met the minimal clinically important difference (MCID) for mHHS and VAS score was noted. Component placement analysis was conducted based on the safe zones defined by Lewinnek and Callanan and the Relative Acetabular Inclination Limit. Seventy-six hips were matched, 38 per group. No differences were observed in patient-reported outcomes or the percentage of hips reaching MCID between the groups. The navigation group was 28.8 and 6.8 times more likely to be within the Callanan and Lewinnek safe zones, respectively. Based on the Relative Acetabular Inclination Limit, the navigation group was 3.1 and 6.4 times more likely to be within the 95% and 99% CI safe zones, respectively. Comparable improvements in patient-reported outcomes were observed in the two groups during a minimum 2-year follow-up. Navigation-assisted surgery enhances the accuracy of acetabular component positioning, with a higher likelihood of cup placement within the safe zones. [Orthopedics. 202x;4x(x):xx-xx.].

Simulation analysis and experimental research on static performance of water-hydraulic pressure difference control valve

Many hydraulic tools, like hydraulic cylinders and hydraulic artificial muscle joints are operated by adjusting pressure differences between different zones. Typically, the method employed to change the pressure difference is establishing hydraulic bridges and adjusting liquid resistance. While effective, this method's drawback is complex structures. To address this issue, a water-hydraulic pressure difference control valve, integrating two hydraulic bridges, was designed. The static performances including the output pressure difference, the flow rate and the force acting on the valve core were analyzed using AMESim and computational fluid dynamics simulations. Based on the simulation results, a prototype of voice coil motor direct drive pressure difference control valve was manufactured and the corresponding experiments were carried out. The computational fluid dynamics simulation results show that the internal leakage and the through-flow capacity difference between throttling grooves affect the flow field characteristics of the valve. When the pump pressure is 3 MPa and the valve opening is at the middle position, the internal leakage increases the flow rate from 2.25 L/min to 2.38 L/min, and the through-flow capacity difference reduces the control port pressure from the theoretical analysis of 1.5 MPa–1.41 MPa. Furthermore, combined with the analysis of the external liquid resistance, the AMESim model of the pressure difference control valve is modified. When the pump pressure is 3 MPa, the pressure difference and flow rate average deviations between the modified AMESim model and the experiment are 0.021 MPa and 0.048 L/min. Finally, a rotational angle experiment for a water hydraulic artificial muscle joints showed satisfactory control effects, suggesting the valve's application in controlling hydraulic tools and actuators.

Treatment of patients with periprosthetic infection and management of Paprosky type 2C cavitary defects at the stage of articulating spacer installation

Introduction Due to the constant increase in the number of primary and revision hip arthroplasties, the incidence of complications has been also increasing. Periprosthetic joint infection (PJI) is the most common and dangerous complication in joint arthroplasty, including PJI with cavitary defects of the acetabulum (Paprosky type 2C).The purpose of the work was to demonstrate successful results of managing acetabular defects in patients with periprosthetic infection at the stage of installing an articulating spacer.Materials and methods The patients underwent surgical management of cavitary defects of the acetabulum with allobone plastic material at the stage of installation of an articulating spacer impregnated with antibacterial drugs. A clinical and functional assessment of the effectiveness of treatment of patients with PJI of the hip joint, who underwent bone grafting of acetabular defects at the first stage of two-stage revision arthroplasty, was carried out. Remission of the infectious process was assessed according to the ICM 2013 (International Consensus Meeting), and the function of the affected limb was assessed according to the HHS (Harris Hip Score).Results At a 6-month follow-up after implantation, there were no clinical and laboratory manifestations of PJI and radiological signs of instability of the implant components. Bone grafting was evaluated to be satisfactory; the function of the affected joint restored to 80–90 to HHS points. Remission of the infectious process according to ICM was achieved.Discussion Clinical cases studied demonstrate a positive result of treatin PJI with plastic surgery of cavitary defects of the acetabular bottom at the stage of articulating spacer installation. Filling acetabular defects at the sanitizing stage (implantation of a spacer) subsequently provides improvement of primary fixation and osseointegration of the acetabular component when converting the spacer to a permanent implant. This is due to an increase in the contact area of the acetabular component with bone tissue (native bone and remodeled allobone material).Conclusion The treatment of the first clinical case improved joint function from 24 to 85 HHS points, and in the second from 27 to 76 HHS points. The use of defect filling techniques enabled to stop the infection and improve functional results.