Revision Knee Arthroplasty Research Articles

DAIR for periprosthetic joint infections—One week to save the joint?

BackgroundPredicting the success of a Debridement, Antibiotics, and Implant Retention (DAIR) procedure for periprosthetic joint infection (PJI) for hip and knee joint arthroplasty remains a challenge. A failed DAIR might adversely affect the outcome of any future revision surgery for PJI. Hence, the ability to identify and optimize factors predictive of DAIR success would help target the procedure to the appropriate patient cohort and avoid unnecessary surgery for patients where a DAIR is unlikely to eradicate infection.MethodsA retrospective review of our prospective Bone Infection Group database was performed to identify all patients who underwent a DAIR of their primary or revision hip or knee arthroplasty. All patients had a confirmed PJI as per MSIS 2013 criteria and an outcome according to the MSIS working group outcome-reporting tool. DAIR surgery was then grouped into groups of “successful” or “unsuccessful” outcomes.ResultsSixty-four consecutive patients with an acute PJI underwent a DAIR procedure between 2009 and 2020, with 46 procedures performed for knees and 18 for hips. Treatment was successful in 69% (37 knees and 7 hips). The chance of a successful DAIR was significantly greater if performed at or within one week of symptom onset compared to greater than one-week duration (adjusted odds ratio (OR) 0.11; P = 0.027; 95% CI [0.02–0.78])). For DAIR performed at or within one week of symptom onset, the success rate was 93% for knees and 80% for hips. The chance of a successful DAIR however was not influenced by whether the surgeon was an arthroplasty or non-arthroplasty surgeon (OR 0.28; P = 0.13; 95% CI [0.05–1.48])). Isolated Streptococcus infection had a success rate of 100%. Next came Coagulase-negative Staphylococci (71%) and Methicillin-susceptible Staphylococcus Aureus (65%). Polymicrobial infection had the worst outcome, with a success rate of 40%.ConclusionIn our experience, DAIR surgery performed within one week of symptom onset significantly increased the chance of successful infection eradication. Collaborative work is required to ensure arthroplasty patients can access prompt appropriate surgical decision-making as soon as concerns arise, remove barriers to early assessment and minimise delays to surgery.

Revision of unicompartmental knee arthroplasty: a systematic review

BackgroundUnicompartmental knee arthroplasty (UKA) is a surgical procedure for managing osteoarthritis of one joint compartment, most commonly the medial side. This systematic review investigates the causes of UKA revision. The outcomes of interest were establishing the revision rate, time to revision, and the most common causes of revision in the long- and midterm follow-up.MethodsThis study was conducted according to the 2020 PRISMA statement. In October 2024, the following databases were accessed: PubMed, Web of Science, Google Scholar, and Embase. All the clinical studies investigating the rate and causes of revision in UKA were accessed. Only studies with a minimum of 10 years of follow-up were considered.ResultsData from 56 studies (13,540 patients) were collected. Of them, 65.6% were women. The mean length of the follow-up was 13.1 ± 3.0 years. The mean age of the patients was 65.6 ± 5.6 years, and the mean BMI was 28.5 ± 2.2 kg/m2. Revisions were performed in 8.8% (2641 of 30,140) of implanted UKAs. The mean time to revision was 6.5 ± 2.6 (range, 2.5 to 13.0) years.Conclusion8.8% (2641 of 30,140) of UKAs were revised at a mean time of 6.5 ± 2.6 years.Level of evidenceLevel IV, systematic review.

Knee

The December 2024 Knee Roundup360 looks at: Unicompartmental knee arthroplasty and total knee arthroplasty in the same patient?; Lateral unicompartmental knee arthroplasty: is it a good option?; The fate of the unresurfaced patellae in contemporary total knee arthroplasty: early- to mid-term results; Tibial baseplate migration is not associated with change in PROMs and clinical scores after total knee arthroplasty; Unexpected positive intraoperative cultures in aseptic revision knee arthroplasty: what effect does this have?; Kinematic or mechanical alignment in total knee arthroplasty surgery?; Revision total knee arthroplasty achieves minimal clinically important difference faster than primary total knee arthroplasty; Outcomes after successful DAIR for periprosthetic joint infection in total knee arthroplasty.

The economic impact of two-stage knee arthroplasty revisions: a projection for a specialized health center in Türkiye

Objectives: The increase in the number of arthroplasty surgeries worldwide also leads to an increase in revision surgeries. This study examines the costs of primary and revision arthroplasty treatments in a tertiary university hospital's orthopedics and traumatology clinic. It also explores the impact of revision surgeries on the healthcare system. Methods: Seventy-six patients who had total knee arthroplasty at a university hospital between 01.01.2017 and 30.09.2022 were included in the study. The patients were divided into three groups: primary (n=25), aseptic reasons one-stage revision (n=27), and septic reasons two-stage revisions (n=24). For each patient included in the study, detailed documents regarding medical supplies, anesthesia, operating room, intensive care, consultation, medicine/serum, medical treatment, laboratory, blood and blood products, microbiology, radiology, food, bed, and attendant fees were provided separately by the hospital purchasing and statistics departments. Results: When comparing the costs of primary, one-stage revision, and two-stage revision surgeries, the average costs were 5689 Turkish Lira (₺), 8294.97 ₺, and 40919.67 ₺, respectively. In patients with septic reasons, the group that underwent two-stage revisions had significantly higher costs than the aseptic group in terms of surgery time, hospital stay duration, medication, treatment, surgery, anesthesia, intensive care, laboratory tests, imaging, blood center services, consultations, visits, meal expenses, and invoiced amount (P<0.001). Conclusion: Preventing and treating periprosthetic infections is costly and challenging. We need more research to develop effective protocols and reduce costs. As the number of patients undergoing knee arthroplasty is expected to rise, healthcare systems must ensure the sustainability of public financial resources, especially in public university hospitals.

Data-Driven Approach to Development of a Risk Score for Periprosthetic Joint Infections in Total Joint Arthroplasty Using Electronic Health Records

BackgroundPeriprosthetic joint infection (PJI) is an uncommon, but serious complication in total joint arthroplasty. Personalized risk prediction and risk factor management may allow better preoperative assessment and improved outcomes. We evaluated different data-driven approaches to develop surgery-specific PJI prediction models using large-scale data from the electronic health records (EHRs). MethodsA large institutional arthroplasty registry was leveraged to collect data from 58,574 procedures of 41,844 patients who underwent at least one primary and/or revision hip and/or knee arthroplasty between 2000 and 2019. The registry dataset was augmented with additional clinical, procedural, and laboratory data from the EHRs for more than 100 potential predictor variables. The main outcome was PJI within the first year after surgery. We implemented both traditional and machine learning methods for model development (lasso regression, relaxed lasso regression, ridge regression, random forest, stepwise regression, extreme gradient boosting, neural network) and used 10-fold cross-validation to calculate measures of model performance in terms of discrimination (c-statistic) and calibration. ResultsAll models discriminated similarly in predicting PJI risk, with negligible differences of less than 0.08 between the best- and worst-performing models. The relaxed and fully relaxed lasso models using the Cox model structure outperformed the other models with concordances of 0.787 in primary hip arthroplasty and 0.722 in revision hip arthroplasty, with the number of predictors ranging from nine to 41. The concordances with the relaxed lasso models were 0.681 in primary and 0.699 in revision knee arthroplasty, with a higher number of predictors in the models. Predictors included in the models varied substantially across the four surgical groups. ConclusionsThe incorporation of additional data from the EHRs offers limited improvement in PJI risk stratification. Furthermore, improvement in PJI risk prediction was modest with the machine learning approaches and may not justify the added complexity.

Challenges of Implementing a Human Multi-Tissue Bank in a Public Hospital: From the Perspective of the Quality Management System

Objectives: Various techniques have been developed to manage bone defects in revision knee arthroplasties, including bone grafts, which can be sourced from living or deceased donors as fresh-frozen or freeze-dried bone allografts, typically from bone banks. Human Multi-tissue Banks (HMTB) are crucial health institutions specializing in the procurement, processing, and distribution of human tissues for transplantation and research. They aim to ensure safety and quality in providing tissues for reconstructive surgeries and injury repair, while also advancing research in regenerative medicine. This study reports on the experience of implementing an HMTB and developing its own Quality Management System. Methods: This descriptive, experience report study identifies the historical actions of the HMTB over five years of implementing and operating the bone bank service. Results: The establishment of an HMTB with modern infrastructure and technological advancements, alongside the development and implementation of a quality management system, enabled excellent organization of work processes and the acquisition of the necessary health license to initiate activities. Conclusion: This report serves as a valuable source of information and provides recommendations applicable to the implementation of other human HMTBs.

Etiology and prosthesis model have no influence in the functional outcomes of total knee arthroplasty revision surgery at five years

BackgroundThe rising number of total knee arthroplasty (TKA) replacements and their uncertain functional results according to the revision etiology and the prosthesis model implanted are a challenge for orthopedic surgeons and patients. A better knowledge of these results is mandatory to make the best decision. We present our clinical outcomes with a 5-year follow-up. MethodsWe retrospectively reviewed 104 patients, 108 knees (77 aseptic and 31 septic), who underwent TKA revision surgery from 2007 to 2017 with three different models of prosthesis. KSS score, range of motion (ROM), pain, and independence for walking were recorded at 5 years according to our own database and the clinical interview and compared to the different models of prosthesis and the etiology of the revision. ResultsThe results showed 81.5 % of good or excellent functional outcomes in our patients with a mean KSS score of 76,7 ± 14,3, a mean ROM of 1.68 ± 0.30 radians, and 77 % of them are independent for walking without any aids. The results do not show any difference between the groups comparing the model of prosthesis and the etiology of the revision surgery. ConclusionsAt 5 years, TKA revision surgery offers good clinical and functional outcomes, independence for walking, good range of motion, and low residual pain regardless of the cause of the revision or the model of prosthesis.

Knee joint dislocations-Current epidemiology and treatment in Germany.

Knee joint dislocations, though rare, present significant challenges due to potential complications like vascular and nerve damage, and are known to be often linked to sports injuries, accidents and obesity. This study aims to analyse the epidemiology, incidence and treatment approaches for knee dislocations in Germany from 2019 to 2022. This retrospective cohort study utilized data from the German Institute for the Hospital Remuneration System to examine knee dislocation cases across German medical institutions. Patient data coded under International Statistical Classification of Diseases and Related Health Problems 10 for 'knee dislocation' enabled detailed analysis by age, sex and surgical procedures categorized by operation and procedure codes. The Patient Clinical Complexity Level (PCCL) assessed complication severity. Analysis of 1643 knee dislocation cases revealed an incidence rate of 0.44-0.54 per 100,000 inhabitants annually. During the years 2020 and 2021, there were fewer cases of knee dislocations. Male patients comprised 50%-56% of cases, with an average hospital stay of 11 days. Most cases were PCCL 0 (62%-72%) and predominantly affected patients aged 18-29 years. Anterior tibial dislocations were common among classified cases. Injuries included ligament ruptures, meniscus lesions and grade I soft-tissue injuries. Patients with pre-existing knee prostheses constituted 0%-16% annually. Treatment involved closed reduction, external fixation and surgeries like capsuloligamentous reconstructions and arthroscopic procedures. Revision knee arthroplasty was required in 2%-9% of cases, with obesity rates up to 7%. This study provides valuable insights into the epidemiology, incidence and treatment of knee dislocations in Germany, with a focus on demographic risk factors, treatment complexities and the impact of obesity and knee prostheses. The findings emphasize the importance of specialized care in larger hospitals, comprehensive management of concomitant injuries and the need for improved coding accuracy. Future research should aim to refine treatment protocols. Level III.

Study of neuromuscular activity in preparation for revision knee arthroplasty

The results of an electromyographic study of 13 patients, aged 50–87 years, with aseptic instability of the components of a knee joint endoprosthesis at the stage of preparation for revision arthroplasty, who were treated at the Republican Scientific and Practical Center of Trauma tology and Orthopedics in the period from 2013 to 2020, were analyzed. To assess the orthopedic status, we used: clinical examination, radiography of the knee joint in 2 standard and axial projections, topogram and CT scan. lectrophysiological studies provide important information for elucidating the etiopathogenesis of knee joint endoprosthesis instability. One of the causes of instability may be an imbalance in the activity of the flexor and extensor muscles that develops during walking, subsequently leading to periprosthetic osteolysis, which occurs as a response to the formation of wear and tear products of the components of the endoprosthesis.

Construction and evaluation of a combined diagnostic model for chronic periprosthetic joint infection based on serological tests

BackgroundEarly diagnosis of chronic periprosthetic joint infection (CPJI) is crucial for ensuring effective treatment and improving patient outcomes. However, many auxiliary diagnostic tests are challenging to implement on a large scale due to economic and technical constraints, making CPJI diagnosis difficult. This study aims to design and validate a combined diagnostic model based on commonly used serological tests to evaluate its diagnostic value for CPJI and develop a diagnostic nomogram.MethodsA retrospective study from January 2019 to February 2024 involving 170 patients undergoing knee and hip arthroplasty revision for CPJI and aseptic loosening (AL) was conducted across two medical centers. These patients were divided into the training set and validation set. Patients were categorized into CPJI and AL groups based on infection status. Serological tests conducted upon admission were collected, and single-factor and multi-factor logistic regression analyses were used to identify independent diagnostic factors for early infection. These factors were integrated to construct a nomogram model. The model's performance was evaluated using the receiver operating characteristic area under the curve (AUC), Hosmer–Lemeshow test, decision curve analysis (DCA), and calibration curve, with external validation conducted on the validation set.ResultsMultivariate logistic regression analysis showed that C-reactive protein (CRP), procalcitonin (PCT), and Platelet count/mean platelet volume ratio (PVR) were independent diagnostic factors for CPJI (p < 0.05). The AUCs for diagnosing CPJI using these individual factors were 0.806, 0.616, and 0.700 (p < 0.05), respectively, while their combined detection achieved an AUC of 0.861 (p < 0.05). The DCA clinical impact curve shows the combined model has good clinical utility when the threshold probability of infection presence is between 0.16 and 0.95. Similar results were obtained in the external validation cohort, with the combined detection having an AUC of 0.893.ConclusionThe combined diagnostic model of CRP, PCT, and PVR significantly improves the The combined diagnostic model of CRP, PCT, and PVR significantly improves the diagnostic performance for CPJI compared to individual serum biomarkers. It exhibits good sensitivity, specificity, and clinical applicability, providing valuable references for CPJI diagnosis.

Epidemiology, Classification and Treatment of Femur and Tibia Fractures around Total Knee Arthroplasty (Literature Review)

Summary. Periprosthetic fractures around total knee arthroplasty (TKA) are difficult to treat due to complex fracture morphology, high proportions of injuries associated with osteopenia, and the variability of injury patterns. Periprosthetic fractures associated with TKA are defined as fractures around the knee joint (femur, tibia, or patella) occurring within 5 cm of the intramedullary stem of the prosthesis or 15 cm of the joint. The incidence is estimated to be between 0.3% and 2.5% after primary TKA and up to 28% after revision TKA. There are several surgical and nonsurgical risk factors associated with postoperative periprosthetic fractures. Distal femoral periprosthetic fractures following TKA are the most common and reported to occur in 0.2–1.8% of patients after primary TKA. Tibial periprosthetic fractures have a reported prevalence of 0.07–0.1% in primary and 0.36% in revision knee arthroplasties. Patella fractures are the second most common periprosthetic fractures following TKA, with prevalence ranging from 0.68% to 1.19%, and are usually associated with a resurfaced patella. Several classification systems of periprosthetic fractures around TKA have been published and some treatment recommendations have been provided. However, most systems are subject to criticism and use different classification systems for the tibia, patella, and the femur.A variety of treatment methods are available for periprosthetic fractures. Conservative treatment can include protected weight bearing, splinting, or traction. Surgical treatment commonly involves closed intramedullary nailing or open reduction and internal fixation by plates. In cases of significant bone loss, a revision TKA may be indicated. In general, treatment must be guided based on the stability of the implant and the remaining bone quality, as determined by the presence of osteolysis and the location of the fracture.

Unexpected positive cultures in aseptic revision hip and knee arthroplasty.

The outcomes of patients with unexpected positive cultures (UPCs) during revision total hip arthroplasty (THA) and total knee arthroplasty (TKA) remain unknown. The objectives of this study were to establish the prevalence and infection-free implant survival in UPCs during presumed aseptic single-stage revision THA and TKA at mid-term follow-up. This study included 297 patients undergoing presumed aseptic single-stage revision THA or TKA at a single treatment centre. All patients with at least three UPCs obtained during revision surgery were treated with minimum three months of oral antibiotics following revision surgery. The prevalence of UPCs and causative microorganisms, the recurrence of periprosthetic joint infections (PJIs), and the infection-free implant survival were established at minimum five years' follow-up (5.1 to 12.3). Of the 297 patients undergoing aseptic revisions, 37 (12.5%) had at least three UPCs obtained during surgery. The UPC cohort included 23 males (62.2%) and 14 females (37.8%), with a mean age of 71.2 years (47 to 82). Comorbidities included smoking (56.8%), hypertension (48.6%), diabetes mellitus (27.0%), and chronic renal impairment (13.5%). The causative microorganisms included Staphylococcus epidermidis (49.6%), Bacillus species (18.9%), Micrococcus species (16.2%), and Cutibacterium acnes (16.2%). None of the study patients with UPCs developed further PJIs or required further surgical intervention during follow-up. The prevalence of UPCs during presumed aseptic revision THA and TKA was 12.5%. The most common causative microorganisms were of low virulence, and included S. epidermidis, Bacillus species, Micrococcus species, and C. acnes. Microorganism-specific antibiotic treatment for minimum three months' duration of UPCs in presumed aseptic revision arthroplasty was associated with excellent infection-free implant survival at mid-term follow-up.

Staged revision of the infected knee arthroplasty and endoprosthesis.

Periprosthetic joint infection (PJI) is a challenging complication of any arthroplasty procedure. We reviewed our use of static antibiotic-loaded cement spacers (ABLCSs) for staged management of PJI where segmental bone loss, ligamentous instability, or soft-tissue defects necessitate a static construct. We reviewed factors contributing to their failure and techniques to avoid these complications when using ABLCSs in this context. A retrospective analysis was conducted of 94 patients undergoing first-stage revision of an infected knee prosthesis between September 2007 and January 2020 at a single institution. Radiographs and clinical records were used to assess and classify the incidence and causes of static spacer failure. Of the 94 cases, there were 19 primary total knee arthroplasties (TKAs), ten revision TKAs (varus-valgus constraint), 20 hinged TKAs, one arthrodesis (nail), one failed spacer (performed elsewhere), 21 distal femoral endoprosthetic arthroplasties, and 22 proximal tibial arthroplasties. A total of 35/94 patients (37.2%) had spacer-related complications, of which 26/35 complications (74.3%) were because of mechanical failure of the spacer construct, while 9/35 (25.7%) were due to recurrence of infection. Risk factors for internal failure were a construct where the total intramedullary spacer length was less than twice the length of the central osseous defect (p = 0.009), where proximal or distal intraosseous spacer contact was < 10%, and after tibial tubercle osteotomy (p = 0.005). The incidence of spacer complications significantly increased the time to second stage: mean 157 days (42 to 458) in those without complications versus 227 days (11 to 528) with complications (p = 0.014). The failure rate of static antibiotic-loaded cement spacers is much higher than anticipated. Complications of the spacer significantly increased the time to second-stage revision. The risk of mechanical failure is significantly increased if the spacer is less than double the size of the segmental defect, or if inadequate reinforcement is inserted into the residual bone. These findings serve as a guide for surgeons to avoid mechanical complications with static spacers.

Perioperative Glycemic Variability Influences Infection Rates Differently Following Revision Hip and Knee Arthroplasty

BackgroundRecent investigations have determined that abnormal postoperative glycemia following primary total joint arthroplasty is associated with adverse events. Our study aimed to determine if hyperglycemia and glycemic variability following aseptic revision total joint arthroplasty were associated with periprosthetic joint infection (PJI) within two years postoperatively. MethodsA retrospective review was performed of 2,208 patients within a single institution undergoing aseptic revision total joint arthroplasty from 2012 to 2019. Postoperative glucose values were recorded. Glycemic variability was measured via three parameters: coefficient of variation, mean amplitude of glycemic excursions, and J-index. Logistic regression analyses were performed to examine associations with PJI at 90-day, 1-, and 2-year follow-up. ResultsIn revision hips, all glycemic measures were not associated with PJI at any time point in logistic regression analyses, except for the mean amplitude of glycemic excursions, which predicted PJI at one year (P = 0.045); body mass index was the only factor associated with PJI at all timepoints in all models. In revision knees, all glycemic measures were not associated with PJI at any timepoint in logistic regression analyses; however, PJI rates differed between diabetics and nondiabetics at all time points (P < 0.05). ConclusionsOur findings illustrate that decreasing preoperative body mass index and postoperative glycemic variability may be critical in reducing PJI rates in revision hips. Furthermore, patients who have diabetes should be counseled that they remain at higher risk of PJI regardless of perioperative glucose control after revision knee surgery.

The push-through total femoral prosthesis for revision of a total hip or knee replacement with extreme bone loss.

The aim of the present study was to assess outcomes of using the push-through total femoral prothesis (PTTF) for revision total hip replacement with extreme bone loss. 10 consecutive patients who received PTTF between 2012 and 2018 for revision hip arthroplasty were included in the study. Primary functional outcomes were assessed using Harris Hip Score (HHS), Toronto Extremity Salvage Score (TESS) and Musculoskeletal Tumor Society (MSTS) scores. Range of motion, complications, and ambulatory status were also recorded to assess secondary outcomes. 2 of 10 patients underwent surgery with PTTF for both knee and hip arthroplasty revision. The mean time between index surgery and PTTF was 15 years (3-32 yrs). Acetabular components were revised in 6 of 10 patients during PTTF application. After a mean follow-up of 5.9 years, hip dislocations occurred in 3 patients. All of the dislocated hips were ones with retained conventional non-constrained acetabular bearings. Patient satisfaction was high (MSTS: 67%, HHS: 61.2%, TESS 64.6%) despite high re-operation rate (40%) and minor postoperative problems. PTTF should be considered for hip and knee arthroplasty revision procedures in patients with an extreme bone defect. Consistent usage of constrained liners should be considered to avoid hip dislocation, which was our main problem following the procedure.

Our Impact on Global Warming: A Carbon Footprint Analysis of Orthopaedic Operations.

The health-care sector and particularly the surgical sector are major contributors to the exacerbation of the global climate crisis. Little is known about the carbon emissions caused by surgical procedures. Therefore, the aim of this study was to estimate the carbon footprint associated with common orthopaedic surgical procedures. Eight surgical procedures (total hip arthroplasty, total knee arthroplasty, knee arthroscopy, anterior cruciate ligament reconstruction, shoulder arthroscopy, elective foot surgery, revision hip arthroplasty, and revision knee arthroplasty) were selected for analysis. The inventory process was performed according to the Greenhouse Gas Protocol for all activity occurring in the operating room. The carbon footprint (in CO2 equivalents, CO2e) ranged between 53.5 kg for knee arthroscopy and 125.9 kg for revision knee arthroplasty. Energy consumption accounted for 57.5% of all emissions, followed by other indirect emissions (38.8%) and direct emissions (3.7%). The largest single contributors were the supply chain (34.6%) and energy consumption for ventilation, heating, and air conditioning (32.7%). Orthopaedic surgical procedures produce considerable amounts of CO2. Reduction in and greening of energy consumption, as well as the decarbonization of the supply chain, would have the greatest impact in reducing the carbon footprint of orthopaedic surgical procedures. Orthopaedic surgical procedures contribute to the climate crisis by emitting relevant amounts of CO2. It should therefore be imperative for all orthopaedic surgeons to endeavor to find solutions to mitigate the environmental impact of their practice.

No shortening of the patellar tendon during two-stage total knee arthroplasty revision using articulating spacers.

Surgical techniques in two-stage revision total knee arthroplasty(rTKA) include the use of articulating spacers and static spacers. Shortening of the patellar tendon could be a reason for inferior functional outcomes in two-stage septic rTKA. The aim of this study was to determine if articulating spacers also have negative effects on the extensor mechanism in rTKA. This retrospective study includes 65 consecutive patients (23 women, 42 men, age 71.3 ± 1.2; range, 51.2-88.6 years) undergoing septic two-stage rTKA using an articulating spacer between 2014 and 2021 in a single orthopedic center. For all patients, calibrated true lateral radiographs before total knee arthroplasty (TKA) explantation (T0), directly after TKA explantation (T1), shortly before TKA reimplantation (T2) and 6-8 days after TKA reimplantation (T3) were used to calculate the modified Insall Salvati ratio (mISR). Overall, the mISR decreased significantly immediately after explantation (T0 vs. T1, p = 0.002) from 1.43 ± 0.03 to 1.36 ± 0.03 and remained stable until T2 (1.37 ± 0.02, p = 0.74). Following TKA reimplantation, the mISR increased again to 1.43 ± 0.03 (T3). There were no significant differences between T0 and T3 (p = 0.88). Six out of 65 patients (9%) experienced patellar tendon shortening > 10% at T3. Septic two-stage revision TKA using an articulating spacer does not lead to patellar tendon shortening in the majority of cases. This study suggests that one reason for the improved range of motion after reimplantation may be the use of articulating spacers compared to static spacers.

Comparison of Externally Transferred and Self-Recruited Patients with Hip and Knee Revision Arthroplasty at a Certified Maximum-Care Arthroplasty Center (ACmax).

According to the guidelines of the EndoCert initiative, certified maximum-care arthroplasty centers (ACmax) are obliged to admit patients from certified arthroplasty centers (AC) if these patients need to be transferred to the more specialized ACmax due to difficult replacement and revision procedures as well as after complications in primary care that are beyond the expertise of the smaller centers. This study investigated whether the cohort of transferred patients differed from the patients directly recruited at the ACmax for factors such as severity of diagnosis, comorbidities or outcome. The aim was to determine whether transferred patients increased the resource requirements for the ACmax. A total of 136 patients were included in the retrospective study and analyzed in terms of case severity, length of hospital stays (LOS), Diagnosis-Related Group charges, readmission rate and concomitant diseases. All patients were followed for up to 12 months after the initial hospital stay. There were significant differences between the groups of transferred and self-recruited patients. For example, transferred patients had a higher Patient Clinical Complexity Level (PCCL). Similarly, the increased Case Mix Index (CMI) of transferred patients indicated more intensive care during the inpatient stay. The higher values for the comorbidity indices also supported these results. This had an impact on the LOS and overall costs, too. The differences between the groups were also reflected by adverse events during the one-year follow-up. The higher percentage of patients with septic revisions, whose treatment is especially demanding, among transferred patients aggravated the differences even further. Thus, transferred patients were associated with increased resource requirements for the ACmax. While it serves patients' safety to transfer them to an ACmax with specialized expertise and greater structural quality, the care of transferred patients ties up considerable resources at the ACmax that might only be insufficiently reimbursed by the generalized tariffs.

Revision Knee Arthroplasties Done at Muhimbili Orthopaedic Institute, Tanzania, between 2007 and 2018

Revision Knee Arthroplasties Done at Muhimbili Orthopaedic Institute, Tanzania, between 2007 and 2018

Genetically predicted effects of 10 sleep phenotypes on revision of knee arthroplasty: a mendelian randomization study

BackgroundAccumulating evidence has suggested that sleep disturbances and disorders are common in patients who undergo knee arthroplasty. Revision surgery represents one of the most catastrophic outcomes of knee arthroplasty. However, it remains unclear whether sleep traits are the causes or consequences of knee arthroplasty revision. This study aimed to genetically examine the relationships between sleep traits and knee arthroplasty revision.MethodsTo determine the causal relationship between sleep traits and knee arthroplasty revision, we employed two-sample Mendelian randomization (MR) using summary statistics from the largest publicly available genome-wide association studies (GWASs). The MR design uses genetic variants as instrumental variables to help separate causal relationships from non-causal associations. The main analyses included an inverse variance weighted (IVW) meta-analysis to obtain primary effect estimates. Sensitivity analyses involving the weighted median approach and MR-Egger regression were also conducted to check for potential pleiotropic biases. Numerous complementary sensitivity analyses were also performed to identify statistically significant causal correlations when there were horizontal pleiotropy and heterogeneity across variants. Finally, a reverse MR analysis was performed to evaluate the possibility of reverse causation.ResultsIn the absence of heterogeneity and horizontal pleiotropy, the IVW method revealed that genetically-predicted short sleep duration short sleep duration (average sleep duration of 24 h is 6 h or less) was positively correlated with the risk of knee arthroplasty revision (odds ratio = 1.03, 95% confidence interval = 1.01–1.05, and P = 0.003), while the association between genetically-predicted long sleep duration and knee arthroplasty was negative. The reverse MR analysis did not yield evidence supporting reverse causality relation between knee arthroplasty revision and sleep phenotypes.ConclusionThis research indicated that, of the 10 sleep phenotypes we analyzed, only sleep duration was causally associated with knee arthroplasty revision. These discoveries added to the understanding of the role of sleep traits in the etiology of knee arthroplasty revision, which might further expand our insights into the prevention of knee arthroplasty revision.