Revision Total Knee Replacement Research Articles

Repeat revision TKR for failed management of peri-prosthetic infection has long-term success but often require multiple operations: a case control study.

Prosthetic joint infection (PJI) is associated with poor outcomes and catastrophic complications. The aim of this study was to present the outcomes of re-revision surgery for PJI of the knee following previous failed two-stage exchange arthroplasty. A retrospective analysis was performed of 32 patients who underwent re-revision knee arthroplasty, having already undergone at least one previous two-stage exchange for PJI with a minimum follow-up of two-years for alive patients. Outcomes were compared to a matched control of two-stage revisions for PJI of a primary knee replacement also containing 32 patients. Outcomes investigated were eradication of infection, re-operation, mortality and limb-salvage rate. Successful eradication of infection was achieved in 50% of patients following re-revision surgery, compared with 91% following two-stage exchange of primary knee replacement for PJI (p < 0.001). Fourteen (44%) patients required further re-operation compared with three (9%) patients in the primary group (p = 0.006). Amputation was performed in one case (3%) with thirteen patients (92%) who had infection controlled by debridement, antibiotics and implant retention (DAIR), further revision surgery or arthrodesis. Two patients died with infection (6%) and the long-term rate for infection control was 91%. The mean number of procedures following surgery for the re-revision group was 2.8 (0-9) compared with 0.13 (0-1) for the primary two-stage group (p < 0.001). Five-year patient survival was 90.6% (95% CI 77.1-100). The limb-salvage rate for the re-revision cohort was 97%. Outcomes for re-revision knee arthroplasty for PJI have higher re-operation and failure rates, but no worse mortality than in revisions of primary knee replacements. Failures can successfully be managed by further operation.

Impact of patient and prosthesis characteristics on common reasons for total knee replacement revision: a registry study of 36,626 revision cases from Australia, Sweden, and USA.

Background and purposeTotal knee replacement (TKR) studies usually analyze all-cause revision when considering relationships with patient and prosthesis factors. We studied how these factors impact different revision diagnoses.Patients and methodsWe used data from 2003 to 2019 of TKR for osteoarthritis from the arthroplasty registries of Sweden, Australia, and Kaiser Permanente, USA to study patient and prosthesis characteristics for specific revision diagnoses. There were 1,072,924 primary TKR included and 36,626 were revised. Factors studied included age, sex, prosthesis constraint, fixation method, bearing mobility, polyethylene type, and patellar component use. Revision diagnoses were arthrofibrosis, fracture, infection, instability, loosening, pain, patellar reasons, and wear. Odds ratios (ORs) for revision were estimated and summary effects were calculated using a meta-analytic approach.ResultsWe found between-registry consistency in 15 factor/reason analyses. Risk factors for revision for arthrofibrosis were age < 65 years (OR 2.0; 95% CI 1.4–2.7) and mobile bearing designs (MB) (OR 1.7; CI 1.1–2.5), for fracture were female sex (OR 3.2; CI 2.2–4.8), age ≥ 65 years (OR 2.8; CI 1.9–4) and posterior stabilized prostheses (PS) (OR 2.1; CI 1.3–3.5), for infection were male sex (OR 1.9; CI 1.7–2.0) and PS (OR 1.5; CI 1.2–1.8), for instability were age < 65 years (OR 1.5; CI 1.3–1.8) and MB (OR 1.5; CI 1.1–2.2), for loosening were PS (OR 1.5; CI 1.4–1.6), MB (OR 2.2; CI 1.6–3.0) and use of ultra-high molecular weight polyethylene (OR 2.3; CI 1.8–2.9), for patellar reasons were not resurfacing the patella (OR 13.6; CI 2.1–87.2) and MB (OR 2.0; CI 1.2–3.3) and for wear was cementless fixation (OR 4.9; CI 4.3–5.5).InterpretationPatients could be counselled regarding specific age and sex risks. Use of minimally stabilized, fixed bearing, cemented prostheses, and patellar components is encouraged to minimize revision risk.

Summary of outcomes of a non-invasive biomechanical therapy for patients with knee osteoarthritis

Osteoarthritis (OA) is the second most frequent chronic musculoskeletal (MSK) condition after low back pain and a leading cause of disability in the elderly. The number of people living with disability will continue to rise with the aging of the population. Moreover, the rapid increase in rates of surgical intervention, i.e. Total knee replacement (TKR) and revision TKRs, is expected to place an immense burden on the health care system and society. There is a call for better rehabilitation, new interventions, and disease management for patients with knee OA. The purpose of this article is to review the biomechanics of knee OA and biomechanical interventions and to summarize the current literature on a non-invasive, home-based biomechanical treatment for patients with knee OA. The evidence suggests an improvement in symptoms and biomechanical indicators after using the home-based biomechanical intervention. In the presence of value-based payment to improve efficiency and effectiveness in delivering medical care, these results are promising.

High survival rate at mid-term follow up of porous tantalum cones for bone defects in revision total knee replacement: A 3–11 years follow up report

BackgroundLarge metaphyseal bone losses are commonly encountered in revision total knee arthroplasty (rTKA). Anderson Orthopaedic Research Institute (AORI) type 2 and 3 defects generally require some metaphyseal fixation or augmentation.This study evaluates the midterm results of Porous Tantalum Trabecular Metal™ (TM) cones in revision TKA addressing severe bone loss. MethodsPatients who underwent revision TKA using metaphyseal cones and a varus–valgus constrained (VVC) implant from January 2010 to January 2018 at our institution were identified from a prospective research database. Pre-operative patient characteristics and operative data were reviewed. Postoperative outcomes were compared with pre-operative values. Primary study aims were to evaluate outcomes, including complications and re-operations, radiographic assessment of cones osteointegration, and survivorship. ResultsA total of 101 knees (101 patients) underwent revision TKA with 139 metaphyseal cones (80 tibial, 59 femoral). AORI defect classification was assessed intraoperatively. All patients were available for a minimum of 2 years of clinical and radiographic follow up. Mean follow up was 7.5 years (range 3–11 years).All patients showed significant improvement of clinical outcomes. Fifteen knees required re-operation and nine required revision of the implants, most commonly for recurrent infection (six of nine revisions) with cones removal.Kaplan–Meier survival analysis show a survival rate of 93.9% at 2 years and a survival rate of 90.2% at 5 and 11 years. ConclusionsThis large series illustrates the utility of porous metaphyseal cones in revision TKA with promising clinical and radiographic results and a high survival rate at mid-term follow up.

Clinical and Radiographic Outcomes of Novel 3D-Printed Highly Porous Knee Cone Design.

Metaphyseal bone defects seen at revision total knee replacement (TKA) have traditionally been treated with bone graft or cement. Recently, metal augments have surfaced as viable alternatives to conventional methods previously used in these patients. Newer 3D-printed metal cones offer better biological fixation as a means of improving construct stability. This study aimed to determine clinical and radiographic outcomes of the novel 3D-printed titanium cone augments for femoral and tibial metaphyseal bone defects. A retrospective review was undertaken of 72 patients who underwent revision TKA with metaphyseal cones (Stryker) and stemmed implants from 2015-2017. Knee Injury and Osteoarthritis Outcome Scores (KOOS Jr) and VR/SF-12 scores were recorded. Knee Society radiographic scores were calculated at latest follow up to evaluate for radiolucency and biological fixation. Loosening noted on radiographs and reoperation for any reason were the endpoints to determine survivorship. A total of 68 patients with 78 cones (58 tibial, 20 femoral) met inclusion criteria. Mean follow up was 3.4 years (range 2-5.4 years). The average KOOS Jr score increased from 38 preoperatively to 66 at two years. The average VR/SF-12 PH score increased from 33 preoperatively to 37 at two years. The average VR/SF-12 MH score increased from 46 preoperatively to 54 at two years. Twelve percent of tibial implants and 10% of femoral implants with cones were found to have lucency in at least one radiographic zone. Overall survivorship at latest follow up was 93% with two patients requiring revision for infection, two revised following mechanical complications, and one patient who underwent polyethylene exchange after experiencing mechanical complications. When considering only aseptic loosening, survivorship was 100%. This 3D-printed titanium femoral and tibial cone augment system showed excellent survivorship, biological fixation, clinical outcomes, and radiographic outcomes in the setting of TKA. Further studies are needed for assessment of long-term survivorship.

A study on functional outcome of posterior cruciate ligament substituted total knee arthroplasty

&lt;p class="abstract"&gt;&lt;strong&gt;Background: &lt;/strong&gt;Total knee replacement surgery is considered as a treatment of choice in patients with advanced arthritis, especially in patients where conservative treatment has been failed. Total knee replacement gives good pain relief, functional improvement of knee and correction of deformity.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Methods:&lt;/strong&gt; This is study of 39 patients following total knee arthroplasty, who were operated between August 2017 and March 2020 at MNR Medical College and Hospital, Sangareddy. They were followed up for a minimum period of 1 year and evaluated using oxford knee scoring system. Oxford knee score is designed specifically for measuring outcomes in knee arthroplasty. There were 14 right knees, 10 left knees, 15 bilateral knees.&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Results: &lt;/strong&gt;There was a significant functional improvement of knee in patients and we had achieved excellent results, out of 39 patients and 4 patients had post op suprapatellar fullness, which was relieved with medications for 3 weeks and 2 patients (2 knees) without no signs of immediate post-operative period, developed infection after 6 months followed which underwent staged revision total knee replacement. The outcome categories based on oxford knee scoring system: excellent (40-48), good (30-39), fair (20-29) and poor (0-19).&lt;/p&gt;&lt;p class="abstract"&gt;&lt;strong&gt;Conclusions: &lt;/strong&gt;It is difficult to balance the knee with retention of posterior cruciate ligament, whereas posterior cruciate ligament substituting total knee replacement gives reproducible and good results, hence it is the preferred mode of management.&lt;/p&gt;

Assessment of the primary stability of revision tibial trays augmented with a cementless sleeve in AORI Type III defects

BackgroundPrevious studies have evaluated the initial stability of uncemented tibial components in revision total knee replacement (rTKR) in the presence of an Anderson Orthopaedic Research Institute (AORI) Type II tibial defect. This study sought to evaluate similar metrics in the severe Type III (AORI TIII) defects with combined uncemented stem and sleeve fixation, specifically, the effect of varying the stem’s length and tibial canal engagement upon stability and bone strain. MethodFinite element models generated from the CT scans of 4 tibias with Type III defects were used to investigate the primary stability, in terms of the bone–implant composite peak micromotion (CPM) and microstrains (CPS), achieved after virtual implantations with and without stems. ResultsA stemless rTKR had increased metaphyseal CPM and CPS compared to all stemmed implants. Significant area of the bone supporting the stemless rTKR had CPS greater than bone yield (7000 με). Short engaging stems (≤150 mm construct length), could not achieve reliable engagement in the diaphysis (canal fill ≤ 50%), leading to insufficient reduction of CPS (≥5000 με). Longer engaging stems (170–220 mm construct length), were able to reliably engage the diaphysis (fill ratio ≥ 75%) resulting in CPS ≤ 5000 με. Although, non-engaging stems resulted in increased CPM and CPS compared to engaging stems, long non-engaging stems (170–220 mm construct) appeared to provide additional stability to the rTKR compared to stemless rTKR. ConclusionThe results indicate a likely correlation between uncemented stem engagement and metaphyseal CPS in Type III defects. Excessive strain within the supporting metaphyseal bone is likely to lead to rTKR migration and loosening.

Assessment of Racial Disparities in the Risks of Septic and Aseptic Revision Total Knee Replacements

Black patients are at higher risk of revision total knee replacement (TKR) than White patients, but whether racial disparities exist for both septic and aseptic revision TKR and the reason for any disparities are unknown. To assess the risk of septic and aseptic revision TKR in Black and White patients and to examine interactions among race and socioeconomic and hospital-related variables that are associated with revision TKR risk. This cohort study included residents of New York, California, and Florida who underwent TKR. Patient-level data were obtained from the New York Statewide Planning and Research Cooperative System, California's Office of Statewide Health Planning and Development Patient Discharge Database, and Florida's Healthcare Utilization Project State Inpatient Database from January 1, 2004, to December 31, 2014. Community characteristics were calculated from the US Census and linked to discharges by patient zip code. American Hospital Association Annual Survey data were linked to discharges using hospital identifiers. The analyses were performed from March 1 to October 30, 2020, with subsequent analyses in April 2021. Cox proportional hazards regression modeling was used to measure the association of race with septic and aseptic revision TKR. A total of 722 492 patients underwent primary TKR, of whom 445 616 (61.68%) were female and 61 092 (8.46%) were Black. Black patients were at higher risk of septic (hazard ratio [HR], 1.11; 95% CI, 1.03-1.20) and aseptic (HR, 1.39; 95% CI, 1.33-1.46) revision TKR compared with White patients. Other risk factors for septic revision TKR were diabetes (HR, 1.24; 95% CI, 1.17-1.30), obesity (HR, 1.13; 95% CI, 1.17-1.30), kidney disease (HR, 1.42; 95% CI, 1.29-1.57), chronic obstructive pulmonary disease (HR, 1.22; 95% CI, 1.15-1.30), inflammatory arthritis (HR, 1.53; 95% CI, 1.39-1.69), surgical site complications during the index TKR (HR, 2.19; 95% CI, 1.87-2.56), Medicaid insurance (HR, 1.17; 95% CI, 1.04-1.31), and low annual TKR volume at the hospital where the index TKR was performed (HR, 1.54; 95% CI, 1.41-1.68). Risk factors for aseptic revision TKR were male sex (HR, 1.03; 95% CI, 1.00-1.06), workers' compensation insurance (HR, 1.61; 95% CI, 1.51-1.72), and low hospital TKR volume (HR, 1.14; 95% CI, 1.07-1.22). Patients with obesity had a lower risk of aseptic TKR revision (HR, 0.81; 95% CI, 0.77-0.84). In an analysis within each category of hospital TKR volume, the HR for aseptic revision among Black vs White patients was 1.20 (95% CI, 1.04-1.37) at very-low-volume hospitals (≤89 TKRs annually) compared with 1.68 (95% CI, 1.48-1.90) at very-high-volume hospitals (≥645 TKRs annually). In this cohort study, Black patients were at significantly higher risk of aseptic revision TKR and, to a lesser extent, septic revision TKR compared with White patients. Racial disparities in aseptic revision risk were greatest at hospitals with very high TKR volumes.

Revision total knee replacement: A two-year review of complexity data and regional workload in South West England

BackgroundThe GIRFT report (2012) sought to address the need for sustainable orthopaedic treatment delivered through regional “networks”; the aim being improved care, decreased cost and reduced revision rate. The aims of this study were to record the number and complexity of revision total knee replacements within a regional network using a validated classification over a two-year period and audit this against National Joint Registry (NJR) records. MethodsA region-wide network model where revision TKR cases are assessed locally using the Revision Knee Complexity Classification (RKCC) and local multi-disciplinary team (MDT) was introduced. Data was collected from 8 revision centres over a two-year period using the RKCC. The case volume was audited against the NJR records. ResultsIn year 1 (01/01/2018–31/12/2018) 237 RKCC forms were collected from eight centres. 46% of R2s and 63% of R3s were carried out at the higher volume centre. 211 K2 forms were received by the NJR. In year 2 (01/01/2019–31/12/2019) 252 RKCC forms were collected. 46% of R2s and 64% of R3s were carried out at the higher volume centre. 267 K2 forms were received by the NJR. ConclusionThis is the first published set of revision knee data showing complexity percentages across a region. The RKCC has been successfully introduced into the region and this has been sustained. The findings show that a successful network has been established and majority of complex revision knee surgery is occurring in the high-volume centre. NJR data suggests that the RKCC is capturing the complexity and volume of our work accurately.

Effect of tourniquet use on the risk of revision in total knee replacement surgery: an analysis of the National Joint Registry Data Set

ObjectiveTourniquet use in total knee replacement (TKR) is believed to improve the bone-cement interface by reducing bleeding, potentially prolonging implant survival. This study aimed to compare the risk of revision...

Periprosthetic Joint Infection Is Associated with an Increased Risk of Venous Thromboembolism Following Revision Total Knee Replacement: An Analysis of Administrative Discharge Data.

Little is known about the relationship between infection and the risk of risk of venous thromboembolism (VTE) following orthopaedic surgery. We assessed the 90-day risk of VTE following revision total knee replacement to measure the association between periprosthetic joint infection and the risk of postoperative VTE. We used New York Statewide Planning and Research Cooperative System data to identify all New York State residents undergoing revision total knee replacement from 1998 to 2014. ICD-9-CM (International Classification of Diseases, Ninth Revision, Clinical Modification) codes were used to identify comorbidities and to classify the indication for revision total knee replacement as aseptic, infection, or fracture. The primary outcome was any diagnosis code for VTE recorded for the revision surgery and/or subsequent admissions within 90 days. A multivariable logistic regression model that included demographic characteristics and comorbidities was used to estimate the risk of VTE after revision for infection or fracture, with aseptic revision as the reference group. The present study included 25,441 patients who were managed with revision total knee replacement; the indication for revision was aseptic for 17,563 patients (69%), infection for 7,075 (28%), and fracture for 803 (3%). The mean age (and standard deviation) was 66 ± 12 years, 15,592 (61%) of the patients were female, 3,198 (13%) were Black, 1,192 (5%) were smokers, and 4,222 (17%) were obese. Seven hundred and nineteen patients (2.8%) had VTE within the 90 days after revision total knee replacement, including 387 (1.5%) during the admission for the revision procedure. The 90-day incidence of VTE was 2.1% after aseptic revision, 4.3% after revision for infection, and 5.9% after revision for fracture. The adjusted odds ratio (aOR) for VTE relative to aseptic revision was 2.01 (95% confidence interval [CI], 1.72 to 2.35) for septic revision total knee replacement and 2.62 (95% CI, 1.91 to 3.6) for fracture. A history of VTE was also a strong risk factor for VTE following revision total knee replacement (aOR, 2.01; 95% CI, 1.48 to 2.71). We found that the odds of VTE after revision total knee replacement for infection were double those after aseptic revision total knee replacement. Although fracture accounts for a small percentage of revision total knee replacements, the risk of VTE was 2.6-fold higher after these procedures. The indication for revision total knee replacement should be considered when choosing postoperative VTE prophylaxis. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Balance and constraint in revision TKR: A classification for instability management

Instability is an increasingly common cause and symptom of failure of Total Knee Arthroplasty (TKA). Patients seek ‘Functional Stability’, which is the sum of both a balanced joint and, if necessary, mechanical constraint. The objective of this paper is to classify the different types of TKA instability and their causes. Based on this classification, the authors give methodical recommendations for instability management. Instability classificationInstability in revision TKA can be classified into 3 types based on the management of bone loss and ligamentous deficiency which directs the level of constraint required to achieve functional stability. Type 1Bone deficiency: Revision with restoration of joint line and rebuilding the bony anatomy results in a balanced joint. No increased constraint is needed. Type 2Ligament and soft tissue deficiency: Requires increased constraint to overcome instability Type 3Composite (Total) deficiency: (combined Type 1 and 2).The multiple causes of instability are outlined for each Instability type along with an algorithm for restoring the joint line and adding titrated constraint to restore functional stability.

Revision knee replacement for prosthetic joint infection: Epidemiology, clinical outcomes and health-economic considerations

Prosthetic joint infection (PJI) is a devastating complication of knee replacement surgery. Recent evidence has shown that the burden of disease is increasing as more and more knee replacement procedures are performed. The current incidence of revision total knee replacement (TKR) for PJI is estimated at 7.5 cases per 1000 primary joint replacement procedures at 10 years. Revision TKR for PJI is complex surgery, and is associated to a high rate of post-operative complications. The 5-year patient mortality is comparable to some common cancer diagnoses, and more than 15% of patients require re-revision by 10 years. Patient-reported outcome measures (PROMs) including joint function may be worse following revision TKR for PJI than for aseptic indications. The complexity and extended length of the treatment pathway for PJI places a significant burden on the healthcare system, highlighting it as an area for future research to identify the most clinically and cost-effective interventions.

Infected total knee replacement: How I do a one-stage revision

BackgroundAs part of a session on the infected knee replacement at the British Orthopaedic Association congress in Liverpool, 2019, this topic was delivered as a lecture. The content and ideas of the lecture have been expanded to produce this article. MethodsOne-stage revision total knee replacement is not a new concept but remains controversial. This article is not written to persuade any surgeon to undertake the procedure but to simply give a working framework for how one surgeon performs the operation. We will cover the philosophy underpinning the rationale for single-stage revision (not 2-in-1 revision) including extensile exposure, a defined debridement protocol, reconstruction and fixation, antibiotic delivery and exclusion criteria. ResultsNone. ConclusionThe techniques outlined in this article should give confidence that one-stage revision knee replacement is a viable option when working within a multi-disciplinary team structure.

Cost of Revision Total Knee Replacement: A Protocol for Systematic Review and Meta-Analysis.

BackgroundA major limitation of total knee replacement (TKR), as with other joint replacements, is the risk of revision. Revision TKR is associated with high risk and economic burden to patients, healthcare providers, and societies. It will be worthwhile to assess the economic burden of revision TKR across countries or different study settings. This study aims to review the literature on the cost of revision TKR to assess costs across countries and studies, estimate a pooled cost estimate for homogenous data, and identify major cost components that contribute to the cost burden.MethodsWe will conduct a search of the MEDLINE (OvidSp), EMBASE, Web of Science, Cochrane Library, EconLit, and Google Scholar databases to identify relevant studies, and will use an optimally designed search approach to search for relevant studies. EndNote library will be used to manage the searched studies. Selection will be undertaken in two phases—screening and eligibility. Study selection, data extraction, and assessment of the risk of bias will be performed in duplicate, after which the data will be analysed narratively and a meta-analysis performed for homogenous studies, if possible.DiscussionThis protocol provides a proposed stepwise plan for conducting a systematic review and meta-analysis of the cost of revision TKR. Findings from this systematic review will provide information about the cost across settings and identify the major cost drivers of revision TKR, which will, in turn, stimulate efforts to minimize the cost.Systematic Review RegistrationPROSPERO CRD42020171988.Electronic supplementary materialThe online version of this article (10.1007/s41669-020-00242-7) contains supplementary material, which is available to authorized users.

Opioid use among veterans undergoing major joint surgery managed by a multidisciplinary transitional pain service

BackgroundChronic postsurgical pain and opioid use is a problem among patients undergoing many types of surgical procedures. A multidisciplinary approach to perioperative pain management known as a transitional pain service...

FAILURE REASONS OF METAPHYSEAL SLEEVES IN REVISION TKR

Introduction: Recent evidence demonstrates durable short and mid-term clinical results and radiographic fixation with the use of metaphyseal sleeves in revision TKR. However, a significant percentage of patients require re-revision surgery. The aim of this study was to identify the reasons of the sleeve failure at a minimum follow up of seven years.

Patients Receiving a Primary Unicompartmental Knee Replacement Have a Higher Risk of Revision but a Lower Risk of Mortality Than Predicted Had They Received a Total Knee Replacement: Data From the National Joint Registry for England, Wales, Northern Ireland, and the Isle of Man

BackgroundTo determine unicompartmental (UKR) and total knee replacement (TKR) revision rates, compare UKR revision rates with what they would have been had they received TKR instead, and assess subsequent re-revision and 90-day mortality rates. MethodsUsing National Joint Registry data, we estimated UKR and TKR revision and mortality rates. Flexible parametric survival modeling (FPM) was used to model failure in TKR and make estimates for UKR. Kaplan-Meier estimates were used to compare cumulative re-revision for revised UKRs and TKRs. ResultsTen-year UKR revision rates were 2.5 times higher than expected from TKR, equivalent to 70 excess revisions/1000 cases within 10 years (5861 excess revisions in this cohort). Revision rates were 2.5 times higher for the highest quartile volume UKR surgeons compared to the same quartile for TKR and 3.9 times higher for the lowest quartiles respectively. Re-revision rates of revised TKRs (10 years = 17.5%, 95% confidence interval [CI] 16.4-18.7) were similar to revised UKRs (15.2%, 95% CI 13.4-17.1) and higher than revision rates following primary TKR (3.3%, 95% CI 3.1-3.5). Ninety-day mortality rates were lower after UKR compared with TKR (0.08% vs 0.33%) and lower than predicted had UKR patients received a TKR (0.18%), equivalent to 1 fewer death per 1000 cases. ConclusionUKR revision rates were substantially higher than TKR even when demographics and caseload differences were accounted for; however, fewer deaths occur after UKR. This should be considered when forming treatment guidelines and commissioning services. Re-revision rates were similar between revised UKRs and TKRs, but considerably higher than for primary TKR, therefore UKR cannot be considered an intermediate procedure.

Rasch Analysis for the Knee Injury and Osteoarthritis Outcome Score Joint Replacement Version in Individuals Awaiting Total Knee Replacement Surgery.

The aim of this study was to verify the single-factor structure of the joint replacement version of the Knee Injury and Osteoarthritis Outcome Score (KOOS-JR) and examine its measurement properties in the context of Rasch analysis in patients with end-stage osteoarthritis of the knee (KOA) awaiting total knee replacement (TKR). The study design was retrieval of prospectively collected clinical data. The data were extracted from the presurgery visit for individuals with KOA who were scheduled for primary TKR at a tertiary care hospital. Those who were scheduled for revision of TKR had any other lower extremity injury or surgery during 6 months prior to the presurgery visit, or those who had reported pre-existing neurological impairments affecting the lower extremity functions were excluded during data extraction. The assumptions of Rasch analysis that were examined included the test of fit, fit of residuals, ordering of item thresholds, Pearson separation index, differential item functioning (DIF), dependency, and unidimensionality. The main outcome measure was KOOS-JR. Data were extracted for 283 patients, including 112 men and 160 women, from clinical charts. The KOOS-JR demonstrated good overall fit to the Rasch model. However, it failed to meet the assumption of unidimensionality. None of the items demonstrated DIF or concerns with response thresholds. Person-item threshold distribution indicated that the score for KOOS-JR overestimated person traits with floor and ceiling effects. Reliability statistics were equal to 0.9, suggesting that seven items within the KOOS-JR were internally consistent and reliable. The hypothetical unidimensional KOOS-JR could not be reproduced in our sample in that KOOS-JR had a latent construct. Future research should perform exploratory factor analysis to examine this latent construct.

High Rate of Fusion but High Complication Rate After Knee Arthrodesis for Infected Revision Total Knee Replacement.

Knee arthrodesis is a demanding technique regarding difficulties to achieve bone fusion, control of infection and its associated complications. The purpose of this study was to evaluate if knee arthrodesis should still be indicated after failed revision total knee replacement. This was a retrospective study of 45 patients. Age, gender, follow-up, pathogens, Charlson comorbidity index, time from primary arthroplasty to arthrodesis, number of previous procedures, surgical technique, functional capability assessed by the SF-12 score, limb-length discrepancy after arthrodesis, presence of radiographic knee fusion, and complications were recorded. The mean age at the time of operation was 72years. 29% of patients were men, 71% were women, and the mean follow-up was 8.5years. The average Charlson comorbidity index was 4.5. The most common microorganisms isolated were Staphylococcus epidermidis (29%), Staphylococcus aureus (22%), and Pseudomonas aeruginosa (15%). In 20% of patients, no microorganism was identified, and in 37% of patients the infection was polymicrobial. Time from primary total knee arthroplasty to arthrodesis was 55months, and patients underwent a mean of 3.9 previous surgeries. The surgical technique used was an intramedullary long nail in 95.5%. Functionally, 93.3% of patients walked with weight bearing. The SF-12 was higher after arthrodesis (p < 0.05). Mean limb length discrepancy was 2.4cm. Among the group treated with long intramedullary nailing, 91.1% obtained tibiofemoral fusion. Complications occurred in 37.6% of patients. Knee arthrodesis with a long intramedullary nail after failed infected revision total knee replacement has a high rate of fusion, but the complication rate is high.