Analysis of Total Knee Arthroplasty revision causes

Complications following total knee arthroplasty in patients with prior extensor mechanism dysfunction: A retrospective review

Background

Extensor mechanism disruption following total knee arthroplasty (TKA) is a rare, yet serious complication. While previous patellar abnormalities are a theoretical risk factor for this complication, there is a scarcity of literature describing the impact of prior extensor mechanism dysfunction (EMD) on this and other complications following TKA. In this study, we describe our institutional experience with complications following TKA after EMD.

Methods

Sixty-one knees that underwent total knee arthroplasty between April 2007 and April 2023 in patients with previous EMD were identified. Extensor mechanism dysfunction types included patellar fracture, patellar tendon rupture, patellar realignment surgery, previous patellar dislocation, and a chronic laterally tracking patella impacting extensor mechanism function. Primary outcomes included extensor mechanism failure, infection, dislocation, aseptic loosening, revision surgery, and stiffness requiring manipulation under anesthesia (MUA).

Results

A total of 61 knees, comprised of 53-patients, were included. There were complications witnessed in fifteen patients, leading to a 24.6 % overall complication rate. There was one extensor mechanism disruption in the form of a partial quadriceps tendon tear requiring repair. There was one patellar dislocation requiring reoperation. There were five superficial infections successfully treated non-operatively and four deep infections requiring reoperation. A total of nine reoperations were performed, four of which were revisions. Four patients underwent MUA due to severe post-operative stiffness.

Conclusion

In this study, we found a high complication rate following TKA in patients with previous extensor mechanism dysfunction. There was one case of partial quadriceps tendon rupture requiring repair.

Improvements in Noise Symptoms, Forgotten Joint Scores, and Functional Outcomes With Greater Time Following Total Knee Arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) is an impactful procedure with goals that include pain reduction and improved function, with low levels of prosthesis awareness. The purpose of this study was to determine if patients reported prosthetic noise and noise-related symptoms diminished over the course of time after TKA.

METHODS

This study was a single institutional, retrospective study of patients who underwent primary unilateral TKA from 2018 to 2021. The TKAs were performed by four high-volume, fellowship-trained arthroplasty surgeons. Patients had similar baseline characteristics. Patients completed a survey consisting of four Likert scale questions related to prosthetic noise generation, the Forgotten Joint Score, and the Knee Injury and Osteoarthritis Outcome Score-Joint Replacement. Data were compared between patients who had undergone TKA one to two years earlier (N = 305) and those who had TKA three to four years prior to evaluation (N = 177).

RESULTS

After more time with TKA, patients had significantly lower reports of hearing noise (31.1 versus 43.6%; P = 0.009) and feeling prosthetic noise-related symptoms (28.2 versus 40.3%; P = 0.010). Furthermore, after more time from TKA, patients had significantly higher satisfaction regarding noise-generation (65.5 versus 50.2%; P = 0.012), postoperative Knee Injury and Osteoarthritis Outcome Score-Joint Replacement scores (80.9 versus 75.9; P = 0.005), and Forgotten Joint Scores (65.4 versus 53.8; P < 0.001).

CONCLUSIONS

As more time passes after TKA, patients observe less prosthetic noise generation and have lower levels of prosthesis awareness and greater satisfaction than those who had surgery more recently. It is unclear whether these differences represent real improvement or acclimation to noise over time.

Leukocyte scintigraphy has high specificity but low sensitivity in diagnosing persistent periprosthetic joint infection before reimplantation in two-stage revision

INTRODUCTION

Two-stage revision is considered the gold standard treatment in chronic periprosthetic joint infection (PJI) but no specific criteria or examination exist to determine infection eradication before reimplantation. This study aimed to assess the diagnostic performance of leukocyte scintigraphy after the first-stage procedure in two-stage revision for chronic PJI.

MATERIAL AND METHODS

Patients studied with leukocyte scintigraphy after cement spacer insertion for knee PJI from January 2012 to December 2021 were retrospectively included. Infection was diagnosed using the criteria of the 2018 International Consensus Meeting. When 1 or more minor criteria were positive but the score was < 6, patients were considered not infected if there was no recurrence of infection at least 24 months after the second-stage procedure. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were found.

RESULTS

The final cohort included 67 cases in 61 patients (M: F = 32:35; mean age 74 years). There were 43 true negatives, 8 true positives, 12 false negatives, and 4 false positives. The sensitivity and specificity of leukocyte scintigraphy in diagnosing PJI were respectively 40.0% and 91.5%, PPV was 66.7%, NPV was 78.2%, and accuracy was 76.1%. Staphylococcus Epidermidis was the most frequently isolated microorganism (50%).

CONCLUSION

Due to the high costs and the difficulty in its execution, LLS should not be used routinely but it could represent an additional criterion in doubtful cases. In any case, a thorough evaluation of other pre- and intra-operative tests is essential to determine whether reimplantation or spacer renewal is the best course of action. Special consideration should be given to positive LLS, as its results are highly specific and have a low rate of false positives. Conversely, in over half of infected patients, LLS could give false negatives, making negative LLS results less relevant.

Total Knee Arthroplasty Automated Implant Detector: An Uncertainty-Aware Deep Learning Classifier to Identify Total Knee Arthroplasty Implants

BACKGROUND

A drastic increase in the volume of primary total knee arthroplasties (TKAs) performed nationwide will inevitably lead to higher volumes of revision TKAs in which the primary knee implant must be removed. An important step in preoperative planning for revision TKA is implant identification, which is time-consuming and difficult even for experienced surgeons. We sought to develop a deep learning algorithm to automatically identify the most common models of primary TKA implants.

METHODS

We used an institutional total joint registry (TJR) to pull images and implant data for 9,651 patients (N = 111,519 images). We trained a deep learning model based on the EfficientNet architecture to identify nine different TKA systems across all common knee radiographic views. Model performance was assessed on an internal held-out test set and on an external test set. Conformal prediction was employed to provide uncertainty estimates, and an outlier detection system alerts the user if an image is potentially outside of the model's trained expertise.

RESULTS

The average model accuracy on the held-out test set was 99.7%. The outlier detection system flagged 93% of images in the test set that were marked as outliers during a manual clean of the dataset. On the external test set, the model made one error out of 301 images. The model can process approximately 30 images/second.

CONCLUSION

We developed an automated knee implant identification tool that can classify nine different implant designs and importantly, works on multiple radiographic views and utilizes uncertainty quantification and outlier detection as safety mechanisms.

LncRNA PTS-1 Protects Against Osteoarthritis Through the miR-8085/E2F2 Axis

Background

Osteoarthritis (OA) is a leading cause of pain, disability, and reduced mobility worldwide, characterized by metabolic imbalances in chondrocytes, extracellular matrix (ECM), and subchondral bone. Emerging evidence highlights the critical role of long non-coding RNAs (lncRNAs) in OA pathogenesis. This study focuses on lncRNA PTS-1, a novel lncRNA, to explore its function and regulatory mechanisms in OA progression.

Methods

The expression profile of lncRNAs was assessed using RNA sequencing and qRT-PCR. The expression of lnc-PTS-1 was further validated by qRT-PCR in degenerated cartilage tissues, degenerative primary chondrocytes, and IL-1β-treated C28/I2 cells. Cell viability, proliferation, and apoptosis rates, along with the mRNA and protein levels of apoptosis-related markers (cleaved Caspase 3, cleaved Caspase 9, Bcl-2, Bax), ECM metabolism markers (MMP-3, MMP-13, aggrecan, collagen II), and inflammation-related markers (IL-1β, IL-6, TNF-α) were evaluated using Cell Counting Kit-8, Toluidine Blue staining, Alcian Blue staining, flow cytometry, qRT-PCR, immunofluorescence, and Western Blot. The interaction between miR-8085 and lnc-PTS-1 or E2F2 was investigated through dual luciferase reporter assays and RNA immunoprecipitation (RIP) analyses.

Results

Lnc-PTS-1 expression was significantly downregulated in degenerated cartilage tissues, IL-1β-induced degenerative primary chondrocytes and C28/I2 cells. Functional experiments showed that lnc-PTS-1 knockdown aggravated IL-1β-induced ECM degradation, chondrocyte apoptosis, and inflammation, while its overexpression provided protective effects. Mechanistically, lnc-PTS-1 acted as a competing endogenous RNA (ceRNA) by sponging miR-8085, thereby upregulating E2F2 expression. Notably, miR-8085 upregulation diminished the protective effects of lnc-PTS-1 on ECM degradation, apoptosis, and inflammation, while E2F2 upregulation partially alleviated IL-1β-induced damage. However, these mitigating effects were reversed by miR-8085 overexpression.

Conclusion

These findings identify lnc-PTS-1/miR-8085/E2F2 axis as a novel regulatory mechanism in OA pathogenesis, providing theoretical basis and experimental evidence for the potential clinical application of new lncRNA molecules in the treatment of OA.

Soft tissue flap reconstruction in infected or exposed total knee arthroplasty: A systematic review and network meta-analysis

BACKGROUND

Total knee arthroplasty (TKA) infection or exposure associated with soft tissue deficiency represents a challenging scenario for the reconstructive surgeon. The aim of the study is to determine the most successful reconstructive option for infected or exposed TKA comparing local muscle flaps (LMF), local fasciocutaneous flaps (LFF), and free muscle flaps (FMF).

METHODS

A systematic review and single-arm network meta-analysis (PRISMA) was conducted to compare outcomes of complicated TKA requiring soft tissue coverage with either LMF, LFF and FMF. The protocol was registered on PROSPERO (CRD42023388731). PubMed, Embase, Web of Science and Cochrane Library were queried. MINORS criteria were employed for bias assessment. Outcomes included infection recurrence, TKA failure, above-knee amputation, and arthrodesis.

RESULTS

A total of 30 studies and 555 flaps were included. Pooled prevalence was 0.18 (95% CI: 0.11-0.26) for infection recurrence, 0.18 (95% CI: 0.11-0.28) for arthroplasty failure, 0.10 (95% CI: 0.08-0.13) for above-knee amputation and 0.10 (95% CI: 0.08-0.13) for arthrodesis. Local fasciocutaneous flaps demonstrated the lowest risk of infection recurrence (LFF = 0.04 ± 0.037, LMF = 0.27 ± 0.043, FMF = 0.26 ± 0.092), arthroplasty failure (LFF = 0.11 ± 0.068, LMF = 0.28 ± 0.045, FMF = 0.22 ± 0.094) and knee arthrodesis (LFF = 0.03 ± 0.027, LMF = 0.14 ± 0.03, FMF = 0.08 ± 0.06) after flap coverage of infected TKA. Free muscle flaps were associated with the lowest risk of above knee amputation (FMF = 0.08 ± 0.07, LFF = 0.10 ± 0.07, LMF = 0.11 ± 0.03). The mean MINORS score was 11.1 (95% CI: 11-12) with major weakness being the lack of prospective enrollment of the patients.

CONCLUSION

Based on the available literature, when appropriate, LFF appear to be the best reconstructive choice for soft tissue reconstruction in complicated TKA.

Stem fixation techniques in revision total knee arthroplasty: A systematic review and meta-analysis

Purpose

This systematic review and meta-analysis aimed to compare the clinical and radiological outcomes of patients undergoing revision total knee arthroplasty (rTKA) using uncemented press-fit stems (hybrid fixation) versus cemented stems (cemented fixation). It is also examined whether cemented fixation offers any superiority over hybrid fixation regarding implant survival, clinical function, imaging analysis and complication rates.

Methods

Following the PRISMA guidelines, a systematic review and meta-analysis were conducted on five databases (Pubmed, Scopus, Embase, Medline and Cochrane). Articles were evaluated according to levels of evidence (LoE). Retrospective studies were analysed with risk of bias in nonrandomised studies of interventions (Robins-I) and randomised controlled trials with risk of bias 2 (RoB-2). This review was registered in the International Prospective Register of Systematic Reviews database. Meta-analysis was performed using R software, with p < 0.05 considered statistically significant.

Results

Data from 12 comparative studies with 1303 patients (1352 rTKAs) were analysed. Survival rates of hybrid and cemented fixations were comparable, with a significant trend favouring hybrid fixation (p = 0.04). Infection and aseptic loosening were the most common causes of failure. Radiographic failure rates showed no significant differences between fixation methods (p = 0.4). Meta-analysis indicated better results with hybrid fixation, although not statistically significant (KSS functional p = 0.15; KSS clinical p = 0.5). High heterogeneity was observed due to variations in patient characteristics and surgical strategies.

Conclusion

Both hybrid and cemented fixation techniques achieve satisfactory clinical results in rTKA, with hybrid fixation demonstrating an overall lower failure rate. The choice of fixation method must be tailored to individual patient characteristics and surgical considerations. Further high-quality randomised trials are needed to refine these results and optimise fixation strategies to improve patient outcomes.

Level of Evidence

Level IV.

Detection of Multiple Tibial Malalignment-Induced Early Polyethylene Breakage Using Single Plane Fluoroscopy: A Case Report

CASE

A 75-year-old woman underwent cruciate retaining total knee arthroplasty (TKA) for osteonecrosis of the knee, converted from unicompartmental arthroplasty due to an intraoperative medial tibial plateau fracture. Four years later, she experienced persistent knee pain. Computed tomography revealed tibial malalignments in 2 planes. In vivo kinematic analysis using single-plane fluoroscopy, which can visualize the femorotibial contact, indicated varus thrust with lateral subluxation of the tibial component and the femoral component recessing into the polyethylene insert. Revision TKA affirmed the polyethylene insert breakage.

CONCLUSION

Malalignment might have caused mechanical failure, and in vivo kinematic analysis was useful to visualize abnormal kinematics in TKA.

Super-Obesity is Associated With an Increased Risk of Complications Following Primary Total Knee Arthroplasty

BACKGROUND

Obesity, defined as a body mass index (BMI) ≥ 30, is an ever-growing epidemic, with > 35% of adults in the United States currently classified as obese. Super-obese individuals, defined as those who have a BMI ≥ 50, are the fastest-growing portion of this group. This study sought to quantify the infection risk as well as the incidence of surgical, medical, and thromboembolic complications among super-obese patients undergoing total knee arthroplasty (TKA).

METHODS

An all-payer claims database was used to identify patients who underwent elective, primary TKA between 2016 and 2021. Patients who had a BMI ≥ 50 were compared to those who had a normal BMI of 18 to 25. Demographics and the incidence of 90-days postoperative complications were compared between the 2 groups. Univariate analysis and multivariable regression were used to assess differences between groups.

RESULTS

In total, 3,376 super-obese TKA patients were identified and compared to 17,659 patients who had a normal BMI. Multivariable analysis indicated that the super-obese cohort was at an increased postoperative risk of periprosthetic joint infection (adjusted odds ratio [aOR] 3.7, 95% confidence interval [CI]: 2.1 to 6.4, P < .001), pulmonary embolism (aOR 2.2, 95%-CI: 1.0 to 5.0, P = .047), acute respiratory failure (aOR 4.1, 95%-CI: 2.7 to 6.1, P < .001), myocardial infarction (aOR 2.5, 95%-CI: 1.1 to 5.8, P = .026), wound dehiscence (aOR 2.3, 95%-CI: 1.4 to 3.8, P = .001), and acute renal failure (aOR 3.2, 95%-CI: 2.4 to 4.2, P < .001) relative to patients who have normal BMI.

CONCLUSIONS

Super-obese TKA patients are at an elevated risk of postoperative infectious, surgical, medical, and thromboembolic complications. As such, risk stratification, as well as appropriate medical management and optimization, is of utmost importance for this high-risk group.

Functional and radiological outcomes of total knee arthroplasty using posterior-stabilized U2 knee system: A retrospective study in 560 cases at five years of follow-up

PURPOSE

The purpose of this study was to assess clinical and functional outcomes as well as the prosthesis survival rates of the U2 Knee system in primary total knee arthroplasty (TKA) with a minimum follow-up of four years.

METHODS

We retrospectively analyzed 560 consecutively primary TKA performed between 2015 and 2019 due to osteoarthritis with a mean follow-up of 5.4 ± 1.1 years. The clinical outcomes were assessed using the knee society score (KSS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). Radiographic outcomes were assessed using the American knee society's roentgenographic evaluation system. Prosthetic survival was calculated using the Kaplan-Meier method.

RESULTS

Postoperative KSS showed significant improvement at one year (Clinical: 37.4 ± 4.1 vs. 91.9 ± 3.7; p < 0.01; Functional: 41.2 ± 3.3 vs. 90.6 ± 4.8; p =  < 0.01), with these improvements maintained throughout the follow-up period. The WOMAC score improved from 60 ± 10.1 preoperatively to 10.9 ± 8.3 (p = 0.02) at the end of the follow-up. There were 20 (3.7%) knees with radiolucent lines around the implant (< 2 mm), and none showed evidence of loosening. There were six (1.1%) revisions-four due to prosthetic joint infections and two due to periprosthetic femur fracture. The prosthetic survival was 97.8% at the study closure.

CONCLUSION

The U2 knee system demonstrates effective and safe performance for primary TKA with significant improvements in functional scores, patient-reported outcomes, and a promising prosthesis survival rate at mid-term follow-up. We will continue with the series analysis to assess the long-term outcomes.

Post-Traumatic Stress Disorder as a Risk Factor for Adverse Outcomes in Total Knee Arthroplasty

BACKGROUND

There is a scarcity of literature concerning individuals who have existing post-traumatic stress disorder (PTSD) and their outcomes after primary total knee arthroplasty (TKA). This study compared outcomes in patients undergoing primary TKA who have a previous history of PTSD.

METHODS

An electronic health care database was used to identify patients diagnosed with PTSD undergoing TKA. Through 1:1 ratio propensity matching, these patients were matched with a cohort of non-PTSD (NPTSD) individuals. Postoperative parameters, including health care visits and prescriptions, were assessed within a 1-month time frame following surgery. Complications and revision rates were evaluated after one month, 6 months, one year, 2 years, and 5 years. A total of 646,186 patients undergoing primary TKA were identified. Ultimately, 7,381 patients who had PTSD were propensity matched to 7,381 NPTSD patients.

RESULTS

Patients who had PTSD presented to the emergency department at a higher rate than NPTSD patients within 7 days (OR [odds ratio]: 1.5; CI [confidence interval]: 1.0 to 2.4) postoperative. Within one month, cohorts were prescribed opioid analgesics at similar rates (OR: 0.9; CI: 0.8 to 1.1). Patients who had PTSD were found to have a higher number of infections within one month (OR: 1.7; CI: 1.2 to 2.6) and 5 years (OR: 1.2; CI: 1.0 to 1.5), periprosthetic fractures at 6 months (OR: 2.1; CI: 1.0 to 4.5) and one year (OR: 2.1; CI: 1. to 4.0), and higher revision rates at all time points.

CONCLUSIONS

Patients diagnosed with PTSD exhibited higher rates of periprosthetic infections at one month and 5 years and increased periprosthetic fracture rates at 6 months and one year after TKA compared to NPTSD patients. These findings underscore the importance of tailored early postoperative education and understanding outcomes for patients who have PTSD in contrast to those who do not have a diagnosis of PTSD.

Does Combined Treatment with Tranexamic Acid and Vancomycin Affect Human Chondrocytes In Vitro?

Background: The aim of our study was to examine the combined effects of tranexamic acid (TXA) and vancomycin powder (VP) on chondrocytes in vitro. Despite the use of TXA and VP being linked to a reduced risk of extensive postoperative blood loss and periprosthetic joint infections (PJIs) in TKA, the possible cytotoxic side effects on periarticular cell types remain unclear. Methods: Human chondrocytes were harvested from hyaline cartilage and expanded in monolayer culture before being simultaneously exposed to different concentrations of TXA and VP for varying exposure times. Cell viability and proliferation were assessed using an ATP assay and an Annexin 5 assay, respectively, while changes in the relative expression of chondrogenic marker genes were examined using semiquantitative RT-PCR. Results: The simultaneous exposure of chondrocytes to TXA and VP for more than 48 h led to a reduction in both cell viability and proliferation rates. When exposing chondrocytes to the lowest examined concentrations of both TXA (10 mg/mL) and VP (3 mg/mL), the observed effects were delayed until 96 h. However, our study found no dependencies of the observed effects on the concentrations tested. Further, we found no effects on the expression of chondrogenic marker genes. Conclusions: Consequently, limiting the exposure time of chondrocytes to TXA and VP in an in vitro setting to 24 h may be considered safe and could help to further improve the understanding of the safe use of substances in vivo. However, further in vitro research is required to develop a comprehensive understanding of the effects of both VP and TXA on important periarticular cell types in TKA, including chondrocytes, osteocytes, and tenocytes.

Innovative Nanotechnological Approaches in Trauma and Orthopaedic Surgery: A Comprehensive Review

The application of nanotechnology to health has been one of the revolutionizing factors in the field of trauma and orthopaedic surgery over the last decade. Advances in nanomedicine, in comparison to conventional modes of treatment, have influenced immensely the approach towards trauma and orthopaedic surgery and provided some unique answers to some very complex problems like bone reconstruction, soft tissue repair, and prevention of infection. The current narrative review intends to underpin an extensive analysis of modern applications and recent advances in nanotechnology-driven therapies in orthopaedics. Having leveraged unique properties inherent in nanoparticles and nanoscale materials, novel interventions, such as nanostructured scaffolds, drug delivery systems, and bioactive coatings, have flourished into a variety of promising means to enhance osseointegration, accelerate the healing process, and reduce postoperative complications. This review at once acknowledges the huge potential of these technologies and some of the problems impeding their wide-range clinical application, including long-term safety, main regulatory hurdles, and scale-up issues. The following review aims to give orthopaedic surgeons, researchers, and biomedical engineers an overview of the present status and perspectives for the future regarding nanomedicine in trauma and orthopaedic surgery, pointing out the expectations of a much-improved outcome in patients and overall quality of life.

Correlation of revision rate of unicompartmental knee arthroplasty with total knee arthroplasty: a meta-analysis of clinical studies and worldwide arthroplasty registers

INTRODUCTION

The purpose of this study was to elucidate differences and similarities in revision rates amongst studies and national registers featuring total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA). Thereby comparability and reproducibility between study and register findings should be created.

MATERIALS AND METHODS

Clinical studies published between 2004 and September 2023 involving TKA or UKA were reviewed for total arthroplasty numbers, revision rates and demographic data. Findings were calculated as "revisions per 100 component years (CY)" and divided according to the nationality of the center. National arthroplasty registers were searched for numbers of arthroplasties and revisions alongside with demographic data. Revision rates in registers were compared to one another and comparison to revision rates from collected studies was drawn.

RESULTS

After evaluation, 98 studies and seven registers met our inclusion criteria and were included in this study. Cumulative percent revision rate in studies was 3.35% after a mean follow-up of 5.7 years, corresponding to 0.71 revisions per 100 CY for TKA and 7.67% after a mean follow-up of 4.9 years, corresponding to 1.3 revisions per 100 CY for UKA. Registers showed mean overall revision rates of 5.63% for TKA and 11.04% for UKA.

CONCLUSIONS

A positive correlation of revision rates of TKA and UKA in studies and registers was found, with overall revision rates of UKA comparted to TKA being 2.29 times higher in clinical studies and 1.96 times higher in registers. Revision rates in registers were 1.56 times higher than presented in clinical studies.

Asymptomatic Elevated Inflammatory Markers: Is There a Risk for Infection or Revision in Primary Total Knee Arthroplasty?

BACKGROUND

Total knee arthroplasty (TKA) is the treatment of choice for advanced knee osteoarthritis. Long-term studies report high patient satisfaction, while complications such as periprosthetic joint infection (PJI) can be devastating. Knowledge regarding risk factors for PJI is critical to minimize and ideally avoid complications. The purpose of this study was to investigate the risk of PJI and revision in patients who had preoperative asymptomatic high C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) levels in primary TKAs.

METHODS

Patients undergoing primary TKA between 2010 and 2022 were eligible. Inclusion criteria were patients who had preoperative complete biochemical parameters and a minimum follow-up of 12 months. Patients who died during the first year, and those who had a history of inflammatory arthritis, autoimmune disease, renal pathologies, or septic arthritis, were excluded. Patients who had elevated blood CRP and ESR levels taken within 48 hours before surgery underwent a thorough medical examination with a focus on infection symptoms. After screening and consultation, residual elevated CRP and ESR levels were classified as asymptomatic. After exclusions, 1,528 patients were included. The mean age was 66 years (range, 35 to 92), and the mean follow-up time was 6.4 years (range, 1.6 to 12.3).

RESULTS

The rate of revision within one year after surgery was 1.6%, whereas the rate of revision in the first 5 years was 3.8%. The PJI rates for the 1st and 5th postoperative years were 1.7 and 2.9%, respectively. Regression analysis did not show any of the potential variables to be a risk factor for revision or PJI.

CONCLUSIONS

Asymptomatic elevated acute-phase reactants are not a risk factor for periprosthetic joint infection or aseptic revision. At a mean follow-up of 6.4 years, overall survival was 96.7%, with only 2.2% of patients revised due to a PJI.

Does the Addition of a Tibial Stem Extender in Total Knee Arthroplasty Decrease Risk of Aseptic Loosening in Patients with Obesity? An Analysis from the American Joint Replacement Registry

Mechanical loosening is a leading cause of failure of total knee arthroplasties (TKAs) for which obesity may be a risk factor. With rising rates of obesity and increasing incidence of TKA, the identification of factors to mitigate this cause of failure is necessary. The purpose of this study is to determine if the use of a tibial stem extender (TSE) decreases the risk of mechanical loosening in patients with obesity undergoing TKA. The American Joint Replacement Registry and linked Centers for Medicare & Medicaid Services claims database were utilized to identify a patient cohort with a body mass index (BMI) of 30 kg/m2 or greater and age 65 years or older who underwent primary elective TKA between 2012 and 2021. Patients were divided into cohorts based on obesity class and TSE utilization. The estimated association of TSE use, BMI categories, and covariates with the risk of revisions for mechanical loosening in both unadjusted and adjusted settings was determined. Hazard ratios and their 95% confidence intervals for the risk of mechanical loosening were calculated. A total of 258,775 TKA cases were identified. A total of 538 of 257,194 (0.21%) patients who did not receive a TSE and one patient out of 1,581 (0.06%) with a TSE were revised for mechanical loosening. In adjusted analysis, TSE use was not protective against mechanical loosening and BMI > 40 was not a significant risk factor. Use of a TSE was not found to be protective against mechanical loosening in patients with obesity; however, analysis was limited by the small number of outcome events in the cohort. Further analysis with a larger cohort of patients with TSE and a longer follow-up time is necessary to corroborate this finding.

Linear and Volumetric Polyethylene Wear Patterns after Primary Cruciate-Retaining Total Knee Arthroplasty Failure: An Analysis Using Optical Scanning and Computer-Aided Design Models

(1) Background: Analyses of retrieved inserts allow for a better understanding of TKA failure mechanisms and the detection of factors that cause increased wear. The purpose of this implant retrieval study was to identify whether insert volumetric wear significantly differs among groups of common causes of total knee arthroplasty failure, whether there is a characteristic wear distribution pattern for a common cause of failure, and whether nominal insert size and component size ratio (femur-to-insert) influence linear and volumetric wear rates. (2) Methods: We digitally reconstructed 59 retrieved single-model cruciate-retaining inserts and computed their articular load-bearing surface wear utilizing an optical scanner and computer-aided design models as references. After comprehensively reviewing all cases, each was categorized into one or more of the following groups: prosthetic joint infection, osteolysis, clinical loosening of the component, joint malalignment or component malposition, instability, and other isolated causes. The associations between volumetric wear and causes of failure were estimated using a multiple linear regression model adjusted for time in situ. Insert linear penetration wear maps from the respective groups of failure were further processed and merged to create a single average binary image, highlighting a potential wear distribution pattern. The differences in wear rates according to nominal insert size (small vs. medium vs. large) and component size ratio (≤1 vs. >1) were tested using the Kruskal-Wallis test and the Mann-Whitney test, respectively. (3) Results: Patients with identified osteolysis alone and those also with clinical loosening of the component had significantly higher volumetric wear when compared to those without both causes (p = 0.016 and p = 0.009, respectively). All other causes were not significantly associated with volumetric wear. The instability group differentiated from the others with a combined peripheral antero-posterior wear distribution. Linear and volumetric wear rates showed no significant differences when compared by nominal insert size (small vs. medium vs. large, p = 0.563 and p = 0.747, respectively) or by component (femoral-to-insert) size ratio (≤1 vs. >1, p = 0.885 and p = 0.055, respectively). (4) Conclusions: The study found increased volumetric wear in cases of osteolysis alone, with greater wear when combined with clinical loosening compared to other groups. The instability group demonstrated a characteristic peripheral anterior and posterior wear pattern. Insert size and component size ratio seem not to influence wear rates.

Examining Disparities in Regional Anesthesia Utilization, Opioid Prescriptions, and Pain Scores Among Patients Who Received Primary or Revision Total Knee Arthroplasty at a Veterans Affairs Medical Center: A Retrospective Cohort Study

INTRODUCTION

Total knee arthroplasty (TKA) is one of the most performed surgical operations in the United States. Managing postoperative pain after TKA is of vital importance, as it is positively associated with outcome measures related to recovery of function and quality of life. Two commonly used methods to control postoperative pain are regional anesthesia (RA), consisting of a single or a combination of peripheral nerve and epidural blocks, and pain medication, such as opioids. Our retrospective analysis sought to better understand whether revision versus primary TKA impacted previously discovered disparities in perioperative pain management and use of RA at the Atlanta Veterans Affairs Health Care System (AVAHCS). Before data collection, we hypothesized that revision TKA would have a higher proportion of Black and older patients and that revision TKA patients would have lower postoperative pain scores.

MATERIALS AND METHODS

This was a retrospective analysis of AVAHCS patients who underwent elective unilateral primary or revision TKA surgery between 2014 and 2020. After application of our exclusion criteria, data from 562 patients were analyzed. Data collected included demographics information, type of RA used, and pain scores. Statistical analyses included chi-square test, t-tests, multiple logistic regression, and multiple linear regression, as appropriate to the outcomes of interest.

RESULTS

Revision TKA patients were more likely to be Black (P = .018) and younger (P = .023 for <50 years of age group, P = .006 for 50 to 64 years of age compared to the >65 years group). Black patients, compared to White patients, had significantly higher pain scores at baseline (P = .0086) and at 24 hours postsurgery (P = .0037). Older patients (≥50 years old) had significantly higher baseline pain scores (P = .021 for the 50 to 64 years group, P < .01 for the >65 years group) and significantly lower first postanesthesia care unit pain scores (P < .05). Black race (P < .01) and age > 65 years (P < .01) were associated with a significant decrease in total oral morphine equivalents (OME) prescribed at discharge. None of the predictor variables-race, age, type of surgery (primary versus revision), baseline, and first postanesthesia care unit pain scores-were significantly associated with the use of RA in our cohort.

CONCLUSIONS

Sociodemographic disparities in pain management have been reported in all healthcare systems, including the VAHCS. This moderately sized retrospective study, conducted at a single veterans affairs site, yielded several noteworthy findings. One finding of particular interest was that, despite Black patients reporting higher baseline and 24-hour postoperative pain scores, they were prescribed fewer opioids at discharge. Our results highlight the presence of clinically significant disparities in perioperative TKA pain management, emphasizing the need for continuous investigation and focused mitigation efforts among Veterans.

Big data analysis reveals significant increases in complications, costs, and hospital stay in revision total knee arthroplasty compared to primary TKA

INTRODUCTION

Despite significant advancements in total knee arthroplasty (TKA), some patients require revision surgery (R-TKA) due to complications such as infection, mechanical loosening, instability, periprosthetic fractures, and persistent pain. This study aimed to explore the specific causes leading to R-TKA, associated complications, including infection, mechanical failure, and wound issues, as well as costs, mortality rates, and hospital length of stay (LOS) using data from a large national database.

METHODS

Data from the nationwide inpatient sample (NIS), the largest publicly available all-payer inpatient care database in the United States were analysed from 1 January 2016 to 31 December 2019. The study included 44,649 R-TKA cases, corresponding to 223,240 patients, with exclusions for nonelective admissions. Various statistical analyses were used to assess clinical outcomes, including in-hospital mortality, postoperative complications, LOS, and hospitalization costs.

RESULTS

Among 2,636,880 TKA patients, 8.4% underwent R-TKA. R-TKA patients had higher rates of chronic conditions, including mental disorders (36.4%) and renal disease (9.9%). Additionally, these patients often experienced instability, necessitating revision surgery. Infection (22.3%) was the primary reason for R-TKA, followed by mechanical loosening (22.9%) and instability. Compared to primary TKA patients, R-TKA patients exhibited higher in-hospital mortality (0.085% vs. 0.025%), longer LOS (3.1 vs. 2.28 days), and higher total charges ($97,815 vs. $62,188). Postoperative complications, including blood transfusion (4.6% vs. 1.3%), acute kidney injury (4.4% vs. 1.8%), venous thromboembolism (0.55% vs. 0.29%), infection, and wound problems, were significantly higher in R-TKA patients.

CONCLUSIONS

This study provides detailed insights into t LOS, costs, and complications associated with specific etiologies of revision TKA. Our findings emphasize the need for targeted preoperative optimization and patient education. This approach can help reduce the incidence and burden of R-TKA, improve patient care, optimize resource allocation, and potentially decrease the overall rates of complications in revision surgeries.

LEVEL OF EVIDENCE

Level III.

Rifampin-resistant periprosthetic joint infections are associated with worse functional outcome in both acute and chronic infection types

Periprosthetic joint infections (PJI) pose a significant challenge in orthopaedic surgery, often requiring extensive surgical debridement and prolonged antibiotic treatment to eliminate the causative pathogens. Rifampin, known for its potent activity against biofilms, has been crucial in managing PJI by penetrating and disrupting these formations, thereby improving treatment efficacy. In this sense, antibiotic protocols lacking rifampin have shown increased failure rates. Consequently, the development of rifampin resistance could severely influence the prognosis of PJI. The aim of this clinical study was to assess how rifampin resistance affects the functional outcome in patients with PJI. In this single-centre comparative cohort study, we systematically documented all patients who presented with a PJI during the period spanning from 2018 to 2020. Two distinct groups were established for the study: Group 1 comprised 35 patients with a PJI caused by rifampin-susceptible pathogens and group 2 consisted of 28 patients with PJI caused by rifampin-resistant pathogens. A total of 63 patients (34 females) with a mean age of 68 years and a mean follow up of 37 months were included. The examination of patient-specific parameters did not reveal any identified risk factors as influential. Patients with a rifampin-resistant pathogen underwent a greater number of surgical revisions (6.9 ± 5.1 compared to 3.59 ± 3.39, p = 0.0011) and had extended durations of antibiotic treatment (p = 0.0052). The results of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score revealed significant differences in clinical outcome between both groups in every domain, even when stratified by acute and chronic entities. In total the WOMAC increased significantly from 21.57 ± 14.9 points in group 1 to 71.47 ± 62.7 points in group 2 (p < 0.001). The higher failure rates observed in group 2 were not statistically significant (p = 0.44). The current study demonstrates that PJI caused by rifampin-resistant bacteria are associated with a significantly worse functional outcome in both acute and chronic infection types without significantly affecting total failure rates.

Editorial Commentary: Meniscus Allograft Transplantation With Concomitant High Tibial Osteotomy and Cartilage Restoration Risks Reoperations and Potential Worsening Outcomes Following Subsequent Total Knee Arthroplasty

The management of the 25- to 45-year-old patient with meniscal deficiency, chondral degeneration, and pain remains challenging. With the potential of a knee replacement in the future, the question I wrestle with is, "When is enough enough?" Meniscus allograft transplantation, when combined with osteotomy and/or cartilage restoration procedures, improves functional outcomes compared to preoperative levels but has not been demonstrated to delay progression of osteoarthritis and often leads to reoperations. Moreover, concomitant procedures do not show improved survivorship of the meniscal allograft. While many undergoing these procedures return to active lifestyles, many do not return to preinjury levels. Balanced clinical-patient discussions are needed about the benefits, limitations, and expectations of meniscus allograft transplantation and associated procedures on not only the current condition of the knee but also the future implications, including reoperations and potential worsening outcomes following total knee arthroplasty. Notably, meniscal allograft transplantation and concomitant procedures lead to additional surgeries, with up to a 59% reoperation rate at an average of 43 months. In some, more surgery does not necessarily lead to improved outcomes, and caution should be exercised; only 44% return to preinjury activity level after meniscus allograft transplantation and high tibial osteotomy. Forty percent are disappointed by level and type of sports participation following meniscus allograft transplantation, but only 14% of those patients would not undergo the procedure again.

Robotic-Assisted Total Knee Arthroplasty Results in Shorter Navigation Working Time With Similar Clinical Outcomes Compared to Computer-Navigated Total Knee Arthroplasty

BACKGROUND

Early clinical data are important in the appraisal of newly introduced robotic-assisted surgery (RAS) systems in total knee arthroplasty (TKA). However, there are few studies to date comparing 1-year clinical outcomes between RAS and computer-assisted navigation (CAS), the forerunner in reducing alignment outliers. The aim of this study was to determine if there was a difference between these two groups in early clinical outcomes, including functional outcome and patient-reported outcome measures (PROMs).

METHODS

A total of 158 propensity score-matched patients who underwent primary TKA with either CAS or RAS were retrospectively analyzed. Perioperative outcomes (navigation time, length of stay, complications, readmissions, transfusions, and technical failure), as well as functional outcome measures (range of motion, sit to stand test, timed-up-and-go test, single-leg stance test, calf raises, and step count), and PROMs (Oxford Knee Score, Knee Injury and Osteoarthritis Outcome Score, 12-item Short Form Survey, Forgotten Joint Score-12, and satisfaction) were compared between those who underwent CAS and those who underwent RAS.

RESULTS

Navigation time was shorter in the RAS group compared to the CAS group (mean difference, 15.4 minutes; P < 0.001). There were 2 complications reported in the CAS group (one patellar clunk, one periprosthetic joint infection), but none in the RAS group. There were no other readmissions, transfusions, or technical failures in either group. Postoperatively, there were no clinical differences in function between groups. Clinically meaningful improvement in PROMs was observed in both groups, with no differences.

CONCLUSIONS

The use of RAS resulted in shorter navigation time compared to CAS in TKA. No other differences were observed in early clinical outcomes between patients who underwent RAS and CAS.

Predictors of reoperation and survival experience for primary total knee arthroplasty in young patients with degenerative and inflammatory arthritis

INTRODUCTION

While total knee arthroplasty (TKA) is typically implemented in patients > 65 years old, young patients may need to undergo TKA for pain relief and functional improvement. Current data are limited by older cohorts and short-term survival rates. This study aimed to examine a large sample size of patients with degenerative and inflammatory conditions who underwent primary TKA at a young (≤ 40) age to identify predictors of reoperation, as well 15-year survivorship.

MATERIALS AND METHODS

A retrospective study was performed on 77 patients (92 surgeries) who underwent primary TKA at ≤ 40 years old, between January 1990 and January 2020. Patient charts were reviewed and a multivariable logistic regression model identified independent predictors of reoperation. Kaplan-Meier analysis was employed to build survival curves and log-rank tests analyzed survival between groups.

RESULTS

Of the 77 patients, the median age at the time of surgery was 35.7 years (IQR: 31.2-38.7) and median follow-up time was 6.88 years. Twenty-one (22.8%) primary TKAs underwent 24 reoperations, most commonly due to stiffness (n = 9, 32.1%) and infection (n = 13, 46.4%) more significantly in the OA group (p = 0.049). There were no independent predictors of reoperation in multivariable analysis, and 15-year revision-free survivorship after TKA did not differ by indication (77.3% for OA/PTOA vs. 96.7% for autoimmune, p = 0.09) or between ≤ 30 and 31-40 year age groups (94.7% vs. 83.6%, p = 0.55).

CONCLUSIONS

In this cohort of patients ≤ 40 years old, revision-free survival was comparable to that reported in the literature for older TKA patients with osteoarthritis/autoimmune conditions (81-94% at 15-years). Though nearly a quarter of TKAs required reoperation and causes of secondary surgery differed between degenerative and inflammatory arthritis patients, there were no significant predictors of increased reoperation rate. Very young patients ≤ 30 years old did not have an increased risk of revision compared to those aged 31-40 years.

Microfragmented adipose tissue versus platelet-rich plasma in the treatment of knee osteoarthritis: a systematic review and meta-analysis

This meta-analysis focuses on the controversial efficacy and safety of microfragmented adipose tissue (MFAT) as compared with platelet-rich plasma (PRP) in the clinical treatment of knee osteoarthritis (KOA). We have attempted to provide an evidence-based medicine protocol for the conservative treatment of KOA. Researchers collected and compared randomized controlled trials (RCTs) that used microfragmented adipose tissue and platelet-rich plasma to treat knee osteoarthritis. We searched CNKI, Wanfang Database, CMJD, PubMed, Sinomed, Cochrane Library, and Embase for studies published up to May 31, 2023. Two investigators independently screened literature, extracted data, and assessed bias risk using the Cochrane bias risk tool. The researchers then performed a meta-analysis using Revman 5.4 statistics software provided by the Cochrane Library. A total of 4 randomized controlled trials involving 266 patients (326 knees) were included. There were 161 knees in the MFAT group and 165 knees in the PRP group. Meta-analysis showed a statistically significant difference in VAS scores between the MFAT group and the PRP group at 12 months after treatment [MD=0.99, 95% CI (0.31, 1.67), P=0.004]. This result showed that VAS scores were lower in the PRP group than in the MFAT group, and that PRP injection reduced pain more effectively than MFAT injection. At 6 months after treatment, Tegner activity scale scores in the MFAT group were higher than that in the PRP group [MD=0.65, 95% CI (0.11, 1.19), P=0.02], and the difference was statistically significant. There were no significant differences in the remaining indicators between the two groups. Based on this meta-analysis, PRP appears to be more effective than MFAT in treating KOA in terms of long-term pain relief. However, MFAT was superior to PRP in improving short-term activity function. Overall, there was no significant difference between MFAT and PRP in the treatment of KOA. In addition, MFAT does not increase the risk of adverse events compared to PRP. However, at present, there are few clinical studies on MFAT and PRP, which need to be verified by more rigorously designed clinical trials.

Effect of Adding Stem Extension to a Short-Keeled Knee Implant on the Risk of Tibial Loosening: a Historical Cohort Study

BACKGROUND

Short-keeled tibial implants may be at higher risk of aseptic loosening. Stem augmentation has been suggested to improve its fixation. We aimed to assess whether this technique could decrease the loosening rate of such tibial implants.

METHODS

We retrospectively studied the knees receiving stemmed versus nonstemmed versions of a short-keeled prosthesis. A total of 932 patients undergoing total knee arthroplasty using a Persona prosthesis with >24-month follow-up (mean 53.7) were included, of whom 212 were at high risk of loosening due to osteoporosis or high body mass index (BMI). The rate of tibial aseptic loosening in high-risk patients and in the whole cohort was compared between those with and without stem extension. Multivariable analysis was conducted to identify the risk factors of loosening.

RESULTS

In the whole cohort, in 203 knees (21.8%), a cemented short stem was used, versus 729 knees (78.2%) without. The tibial implant revision rates for loosening were 2.06% and 0.99% for nonstemmed and stemmed cases, respectively (P = 0.551). When the cohort was categorized based on the loosening risk factors, the loosening risk was significantly higher in the high-risk than in the low-risk group, regardless of stem status (log-rank test = 8.1, hazard ratio = 2.17, 95% CI = 1.78, 2.57, P = 0.005). 212 patients were at high risk of loosening, due to high BMI or osteoporosis, among whom the risk of aseptic loosening was higher when a stem was not used (log-rank = 32.1, hazard ratio = 4.95, 95% CI = 4.05, 5.86, P < 0.001). In multivariate analysis, osteoporosis, BMI ≥35, and smoking were correlated with loosening.

CONCLUSION

The failure rate was markedly lower in the stemmed group of the patients at elevated risk of aseptic loosening due to osteoporosis and/or high BMI. In the entire cohort, the risk of loosening in stemmed tibial implants was similar to the nonstemmed group. The findings support a protective role for the stem in patients at high risk of failure of the cemented tibial implant.

LEVEL OF EVIDENCE

III therapeutic.

Performing Revision Arthroplasty Increases Surgeon and Practice Volumes Through the Generation of Subsequent Cases: A Retrospective Study

Background

Revision total knee (TKR) and hip (THR) arthroplasty surgeries are disincentivized due to unfavorable reimbursement rates, surgical times, and complication rates. Our study investigates secondary benefits of performing these surgeries by generating subsequent cases for surgeons and practices.

Methods

Patients undergoing TKR and THR between April 1, 2011, and January 1, 2019, at our tertiary academic institution were analyzed. Patients were identified with Current Procedural Terminology codes for TKR and THR. We calculated a subsequent surgery rate on the same or different joint by the initial surgeon or another surgeon within the practice to determine the procedure yield after initial revision arthroplasty.

Results

One thousand six hundred twenty-five patients met inclusion criteria. Six hundred forty-nine (39.9%) patients received at least one subsequent procedure on any joint by any orthopaedic surgeon in the practice. Four hundred five patients (24.9%) underwent another procedure on any joint by the same surgeon. Two hundred sixty patients (16.0%) underwent another procedure on the same joint by the same surgeon, with 109 cases (41.9%) being a planned second stage of a 2-stage revision for infection. Two hundred eighty-five patients (17.5%) underwent another procedure on a different joint by the same surgeon, with 122 of these patients (42.8%) undergoing at least one primary total hip or knee arthroplasty.

Conclusions

TKRs and THRs can increase surgeon and practice volumes through the generation of future cases, which are primarily the second stage of a 2-stage revision or primary joint arthroplasties on other joints.

Preoperative Laboratory Values Predicting Periprosthetic Joint Infection in Morbidly Obese Patients Undergoing Total Hip or Knee Arthroplasty

BACKGROUND

Morbidly obese patients are an ever-growing high-risk population undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA) for end-stage osteoarthritis. This study sought to identify preoperative laboratory values that may serve as predictors of periprosthetic joint infection (PJI) in morbidly obese patients undergoing THA or TKA.

METHODS

All morbidly obese patients with preoperative laboratory data before undergoing primary elective TKA or THA were identified using the Premier Healthcare Database. Patients who developed PJI within 90 days after surgery were compared with patients without PJI. Laboratory value thresholds were defined by clinical guidelines or primary literature. Univariate and multivariable regression analyses were utilized to assess the association between PJI and preoperative laboratory values, including total lymphocyte count, neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), monocyte-lymphocyte ratio (MLR), systemic immune-inflammation index (SII), albumin level, platelet count, albumin-globulin ratio, hemoglobin level, and hemoglobin A1c.

RESULTS

Of the 6,780 patients identified (TKA: 76.67%; THA: 23.33%), 47 (0.69%) developed PJI within 90 days after surgery. The rate of PJI was 1.69% for patients with a hemoglobin level of <12 g/dL (for females) or <13 g/dL (for males), 2.14% for those with a platelet count of <142,000/µL or >417,000/µL, 1.11% for those with an NLR of >3.31, 1.69% for those with a PLR of >182.3, and 1.05% for those with an SII of >776.2. After accounting for potential confounding factors, we observed an association between PJI and an abnormal preoperative NLR (adjusted odds ratio [aOR]: 2.38, 95% confidence interval [CI]: 1.04 to 5.44, p = 0.039), PLR (aOR: 4.86, 95% CI: 2.15 to 10.95, p < 0.001), SII (aOR: 2.44, 95% CI: 1.09 to 5.44, p = 0.029), platelet count (aOR: 3.50, 95% CI: 1.11 to 10.99, p = 0.032), and hemoglobin level (aOR: 2.62, 95% CI: 1.06 to 6.50, p = 0.038).

CONCLUSIONS

This study identified preoperative anemia, abnormal platelet count, and elevated NLR, PLR, and SII to be associated with an increased risk of PJI among patients with a body mass index of ≥40 kg/m 2 . These findings may help surgeons risk-stratify this high-risk patient population.

LEVEL OF EVIDENCE

Prognostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Assessing the impact of distal femoral morphology using Citak's ratio: an independent risk factor for aseptic loosening in rotating hinge knee prosthesis

BACKGROUND

Aseptic loosening (AL) is a frequent complication after rotating hinge knee (RHK) prosthesis. Citak's ratio has recently been developed to describe and classify distal femoral morphology into 3 groups (A, B, C). It consists in a ratio between the diameters of the femoral canal at 20 cm from the knee joint line and at 2 cm from the adductor tubercle. The objective of the study was to identify whether the femoral distal anatomical shape described with this ratio represents a risk factor for AL in RHK prosthesis.

METHODS

Retrospective study of patients who had undergone primary or revision RHK prosthesis, with a follow-up of minimum 4 years. Citak's ratio was calculated, and patients were classified depending on its value. Univariate and bivariate statistical analysis was performed to identify AL risk factors. Receiver Operating Characteristics (ROC) analyses were conducted to examine diagnostic quality of the parameters of interest.

RESULTS

Thirty-three patients were included. Most of them females (ratio 26:7), with a mean age of 78.2 (SD 6.9). Three patients presented AL (rate of 9%), all of them classified into group C (100%). Citak's ratio was significantly related to the AL rate (p < 0.001), and so was the femoral canal diameter at 20 cm from the knee joint (p 0.010). The ROC curve analysis yielded an Area Under the Curve (AUC) of 0.922 (CI 95% 0.819-1.000) for the Citak´s ratio.

CONCLUSION

The inner femoral diameter at 20 cm proximal to the knee joint line and Citak's ratio help indentify patients at risk of AL after RHK prosthesis, and thus a better planning of the surgery.

Increased Rate of Complications Following Total Knee Arthroplasty in Patients Who Have Marfan Syndrome

BACKGROUND

Outcomes of Marfan syndrome (MFS) patients after total knee arthroplasty (TKA) are poorly documented in the literature. The purpose of this study was to evaluate MFS as a potential risk factor for complications after TKA.

METHODS

Using a national private payer insurance database from 2010 to 2022, MFS patients undergoing primary TKA were identified and compared to 10:1 matched controls based on age, sex, obesity, diabetes mellitus, and a comorbidity index. A total of 4,092 patients undergoing primary TKA were analyzed, of which 372 had MFS. Multivariable logistic regression analyses were done for medical complications up to 90 days and surgical complications up to 2 years. 90-day emergency department-visits and inpatient readmissions were also documented.

RESULTS

Compared to the matched controls, patients who have MFS displayed elevated rates of surgical complications, including prosthetic instability (1-year, odds ratio (OR) 3.88, 95% confidence interval (CI) [1.58 to 8.66]; 2-year, OR 4.39, 95% CI [2.16 to 8.44]), and revision surgery (2 year, OR 1.79, 95% CI [1.05 to 2.91]). Additionally, patients who have MFS demonstrated significant higher rates of medical complications, including aortic dissection (2.15 versus 0%) and transfusion (OR 2.63, 95% CI [1.31 to 4.90]).

CONCLUSIONS

Patients who have MFS are at higher risks of postoperative complications after TKA, encompassing both medical and surgical complications. Specifically, patients who have MFS have a significantly higher likelihood of experiencing prosthetic instability and requiring revision surgery. Given these results, it is crucial for orthopedic surgeons and patients alike to consider these risks when determining a course of TKA for patients who have MFS.

Comparison of anatomic axes with a navigated functional rotation axis determined by ligament tension for rotational femoral component alignment in cadaver knee arthroplasty

INTRODUCION

The malimplantation of the total knee arthroplasty (TKA) components is one of the main reasons for revision surgery. For determining the correct intraoperative femoral rotation several anatomic rotational axes were described in order to achieve a parallel, balanced flexion gap. In this cadaveric study prevalent used rotational femoral axes and a navigated functional rotational axis were compared to the flexion-extension axis defined as the gold standard in rotation for femoral TKA component rotation.

MATERIALS AND METHODS

Thirteen body donors with knee osteoarthritis (mean age: 78.85 ± 6.09; eight females and five males) were examined. Rotational computer tomography was performed on their lower extremities pre- and postoperatively. Knee joint arthroplasties were implanted and CT diagnostics were used to compare the preoperatively determined flexion-extension axis (FEA). The FEA is the axis determined by our surgical technique and serves as an internal reference. It was compared to other axes such as (i) the anatomical transepicondylar axis (aTEA), (ii) the surgical transepicondylar axis (sTEA), (iii) the posterior condylar axis (PCA) and (iv) the functional rotation axis (fRA).

RESULTS

Examination of 26 knee joint arthroplasties revealed a significant angular deviation (p*** < 0.0001) for all axes when the individual axes and FEA were compared. aTEA show mean angular deviation of 5.2° (± 4.5), sTEA was 2.7° (± 2.2), PCA 2.9° (± 2.3) and the deviation of fRA was 4.3° (± 2.7). A tendency towards external rotation was observed for the relative and maximum axis deviations of the aTEA to the FEA, for the sTEA and the fRA. However, the rotation of the posterior condylar axis was towards inwards.

CONCLUSIONS

All axes showed a significant angular deviation from the FEA. We conclude that the presented technique achieves comparable results in terms of FEA reconstruction when compared with the use of the known surrogate axes, with certain deviations in terms of outliers in the internal or external rotation.

Epidemiology and Risk Factors for Revision Total Knee Arthroplasty in Chinese Patients: A Retrospective Study in Changchun, Jilin Province, China

BACKGROUND Over the past decades, total knee arthroplasty (TKA) in China has increased substantially. Owing to a lack of a joint registry, there is restricted information concerning the epidemiology of TKA failures in China. We aimed to (1) investigate the etiology of TKA failures in a cohort of Chinese patients and (2) determine the related demographic and anthropometric risk factors in Jilin, China, to have a look at the actual situation. MATERIAL AND METHODS A total of 1927 primary and 109 revision TKAs performed between April 2014 and May 2022 were analyzed in this retrospective study. Patient demographics and anthropometric measures, the interval from primary TKA to revision procedures, and the mechanisms for primary TKA failure were evaluated. A chi-square test, unpaired t test, and multivariate logistic regression were used to investigate the relationships between different factors and TKA failures. RESULTS The leading failure mechanism was infection (53.3%), followed by aseptic loosening (21.5%), stiffness (15.0%), instability (3.7%), malposition (2.8%), periprosthetic fractures (2.8%), and extensor mechanism disruption (0.9%). Infection (59.7%) was the main reason for early revision. Aseptic loosening (43.3%) was the leading cause of late revision. The male ratio in infection patients was higher (35.1% vs 20.6%). The smoking rate in patients with revision and infection was higher (18.9%, 23.9% vs 7%) than in primary patients. There was no difference in BMI between groups. CONCLUSIONS The leading cause of revision TKA in Jilin, China, was infection, followed by aseptic loosening and stiffness. Sex and smoking history were associated with TKA failures in this region.

Constraint degree in revision total knee replacement: a registry study on 1432 patients

PURPOSE

Total knee replacement (TKR) failure represents a hard challenge for knee surgeons. TKR failure can be managed in revision with different constraint, related with soft and bone knee damages. The choice of the right constraint for every failure cause represents a not summarized entity. The purpose of this study is identifying distribution of different constraints in revision TKR (rTKR) for failure cause and the overall survival.

METHODS

A registry study based on the Emilia Romagna Register of the Orthopaedic Prosthetic Implants (called RIPO) was performed with a selection of 1432 implants, in the period between 2000 and 2019. Selection implants including primary surgery constraint, failure cause and constraint revision for every patient, and divided for constraint degrees used during procedures (Cruciate Retaining-CR, Posterior Stabilized-PS, Condylar Constrained Knee-CCK, Hinged).

RESULTS

The most common cause of primary TKR failure was aseptic loosening (51,45%), followed by septic loosening (29,12%). Each type of failure was managed with different constraint, the most used was CCK in the most of failure causes, such as to manage aseptic and septic loosening in CR and PS failure. Overall survival of TKA revisions has been calculated at 5 and 10 years for each constraint, with a range of 75.1-90.0% at 5 years and 75.1-87.5% at 10 years.

CONCLUSION

Constraint degree in rTKR is typically higher than primary, CCK is the most used constraint in revision surgery with an overall survival of 87.5% at 10 years.

Microvascular free flap coverage of complex soft tissue defects after revision total knee arthroplasty: a cross-sectional observation study

BACKGROUND AND PURPOSE

Soft tissue defects after total knee arthroplasties (TKA) represent a major orthopedic challenge with amputation as a feared outcome. Microvascular free flap coverage (FFC) can increase limb salvage rates, but complications related to the procedure are yet to be explored further. We aimed to review a single-center experience with FFC for soft tissue defects related to revision total knee arthroplasty.

METHODS

Through a retrospective chart review from 2006 to 2021, we identified all patients who had FFC of a knee with an existing TKA. Typically, patients underwent 2-stage revision arthroplasty. To identify areas of intervention, we divided the entire regimen into 2 phases divided by the free flap surgery (pre- and post-free flap).

RESULTS

We identified 18 patients with a median age at free flap surgery of 69 years (range 39-85), who were followed for a median of 5.1 years (range 2 months to 10.6 years). The median duration from primary TKA to their final operation was 17.5 months (range 19 days to 7 years). Patients underwent a mean of 7.6 surgical procedures on their knee with 3.6 orthopedic revisions prior to the FFC and 0.6 after. Soft tissue coverage was achieved in all patients and no patients underwent amputation. One-third of patients experienced early complications at recipient site after free flap surgery. There were no donor site complications.

CONCLUSION

Microvascular FFC of complex soft tissue defects after revision total knee arthroplasty proved achievable in all patients with successful limb salvage in all patients.

Frailty Among Revision Total Knee Arthroplasty Recipients: Epidemiology and Propensity Score-weighted Analysis of Effect on In-hospital Postoperative Outcomes

BACKGROUND

Frailty has been shown to correlate with worse outcomes after total knee arthroplasty (TKA), although less is known regarding its effect on revision TKA (rTKA). This study examines the epidemiologic characteristics and inpatient outcomes of patients with frailty undergoing rTKA.

METHODS

Discharge data from National Inpatient Sample registry were used to identify all patients aged 50 years or older who underwent rTKA between 2006 and 2015. Patients were stratified into frail and nonfrail groupings, based on the presence of specific International Classification of Diseases-9 diagnostic coding. An analysis comparing the epidemiology, medical comorbidities, and propensity score-weighted postoperative clinical and economic outcomes of the two groups was done.

RESULTS

From 2006 to the third quarter of 2015, a total of 576,920 patients (17,727 frail) who underwent rTKA were included. The average age in the study's population was 67.2 years, with a female distribution of 57.4%. Frail patients were more likely to exhibit markedly higher rates of almost all modified Elixhauser Comorbities than their nonfrail counterparts. Frail patients were also more likely to undergo different types of revisions, including an increased rate of removal of the prosthesis without replacement. In addition, frail patients displayed increased likelihood of experiencing any postoperative complication, deep vein thrombosis, postoperative anemia, respiratory complications, and wound dehiscence. Frail patients experienced lower rates of discharge home and increased length of stay than the nonfrail cohort.

DISCUSSION

Patients with frailty undergoing rTKA are at markedly higher risk for inpatient postoperative complications and increased length of stay. Understanding the implications of frailty within rTKA is essential for risk assessment and preoperative optimization for this expanding population.

Diagnostic value of procalcitonin in patients with periprosthetic joint infection: a diagnostic meta-analysis

Background

The success rate of periprosthetic joint infection (PJI) treatment is still low. Early diagnosis is the key to successful treatment. Therefore, it is necessary to find a biomarker with high sensitivity and specificity. The diagnostic value of serum procalcitonin (PCT) for PJI was systematically evaluated to provide the theoretical basis for clinical diagnosis and treatment in this study.

Methods

We searched the Web of Science, Embase, Cochrane Library, and PubMed for studies that evaluated the diagnostic value of serum PCT for PJI (from the inception of each database until September 2020). Two authors independently screened the literature according to the inclusion and exclusion criteria. The quality of each selected literature was evaluated by using the Quality Assessment of Diagnostic Accuracy Studies tool (QUADAS-2) tool. RevMan 5.3 software was used for the quality evaluation. The sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were merged by using Meta-DiSc 1.4 software. The area under the curve (AUC) and Q index were calculated after the summary receiver operating characteristic (SROC) was generated. We also performed subgroup analysis.

Results

A total of 621 patients were enrolled in the nine studies. The pooled sensitivity of serum PCT for PJI diagnosis was 0.441 [95% confidence interval (CI), 0.384-0.500], the pooled specificity was 0.852 (95% CI, 0.811-0.888), the pooled PLR was 2.271 (95% CI, 1.808-2.853), the pooled NLR was 0.713 (95% CI, 0.646-0.786), and the pooled DOR was 5.756 (95% CI, 3.673-9.026). The area under SROC (the pooled AUC) was 0.76 (0.72-0.79). Q index was 0.6948.

Conclusion

This study showed that PCT detection of PJI had poor diagnostic accuracy. Hence, the serum PCT is not suitable as a serum marker for PJI diagnosis.

Barriers and facilitators of implementation of new antibacterial technologies in patient care: an interview study with orthopedic healthcare professionals at a university hospital

BACKGROUND

Antimicrobial resistance is a major global health threat. Therefore, promising new antibacterial technologies that could minimize our dependence on antibiotics should be widely adopted. This study aims to identify the barriers and facilitators of the adoption of new antibacterial technologies in hospital patient care.

METHODS

Semi-structured interviews, based on the Consolidated Framework for Implementation Research, were conducted with healthcare professionals related to the orthopedics department of an academic hospital in The Netherlands.

RESULTS

In total, 11 healthcare professionals were interviewed. Scientific evidence for the effectiveness of the technology was the most explicitly mentioned facilitator of adoption, but other (often contextual) factors were also considered to be important. At the level of the inner and outer setting, high costs and lacking coverage, competition from other firms, and problems with ordering and availability were the most explicit perceived barriers to adoption. Participants did not collectively feel the need for new antibacterial technologies.

CONCLUSIONS

Barriers and facilitators of the adoption of new antibacterial technologies were identified related to the technology, the hospital, and external factors. The implementation climate might have an indirect influence on adoption. New antibacterial technologies that are scientifically proven effective, affordable, and easily obtainable will most likely be adopted.

Case Report: Total Knee Arthroplasty in Ipsilateral Below-Knee Amputee

Introduction

Total knee arthroplasty (TKA) has the highest annual incidence among all joint replacement surgeries. Below-knee amputation (BKA) is another common procedure to treat lower-limb-threatening pathologies. These two procedures are commonly performed individually, but an ipsilateral TKA performed on a BKA patient is rare. While ipsilateral amputation is not a contraindication for TKA, it presents orthopaedic surgeons with a unique case and necessitates thoughtful pre-operative planning regarding proper positioning, alignment determination, surgical technique, and rehabilitation for the best outcome.

Objectives

We present a case of a patient with a BKA who underwent ipsilateral TKA.

Case Report

This patient has a history of osteoarthritis (OA) of the right knee and diabetic neuropathy and underwent a right BKA after sustaining second-degree thermal burns to the bilateral forefeet. The patient was scheduled to undergo elective TKA prior to these injuries but was forced to postpone due to their severity. Following the BKA, the patient regained his ability to ambulate independently with prosthesis but continued to suffer from OA symptoms. The patient was then scheduled for surgery, and a TKA was performed.

Conclusion

The patient underwent a TKA and tolerated the surgery well without complications. Appropriate positioning was achieved using a popliteal post. Alignment and tibial cut were checked using fluoroscopy. All components were cemented into position, and the patella was resurfaced. The patient did well postoperatively and was using his prosthesis and ambulating independently at the final follow-up.

Natural History of Opioid Use in Naive and Tolerant Patients in Revision Total Hip Arthroplasty

BACKGROUND

Opioid use after revision total hip arthroplasty (rTHA) has not been well characterized. The purpose of this study was to characterize preoperative, perioperative, and postoperative opioid use during rTHA.

METHODS

Patients undergoing revision THA from 2010 to 2018 were screened for opioid use 3 months before revision surgery and tracked 24 months postoperatively. Patients were categorized as naïve or tolerant. Opioid prescriptions and average morphine milligram equivalents (MME) were compared between the two groups.

RESULTS

One hundred twenty-four of 247 patients (50%) in the tolerant group averaged a preoperative MME of 23.7 mg/day. Postoperatively, tolerant patients received significantly higher daily MME at all time points, including at 3 months 31.4 versus 18.1 mg/day (P < 0.001), 6 months 19.9 versus 2.95 mg/day (P < 0.001), 12 months 14.3 versus 3.5 mg/day (P < 0.001), and 24 months 10.7 versus 2.17 mg/day (P < 0.001). Tolerant patients were more likely to have a prescription at 6 months (44% versus 22%), 12 months (41.4% versus 24%), and 24 months (38% versus 19.3%) (P < 0.001, P = 0.002, P < 0.001, respectively).

DISCUSSION

Opioid-tolerant patients had higher postoperative MME requirements for longer recovery duration. Both groups reduced opioid use at 3 months and plateaued at 6 months. These findings can help the revision surgeon counsel patients and expectations.

Analysis of the incidence and risk factors of blood transfusion in total knee revision: a retrospective nationwide inpatient sample database study

OBJECTIVE

This study sought to determine the incidence and risk factors of blood transfusion among patients undergoing total knee revision (TKR) using a nationwide database.

METHODS

A retrospective data analysis was conducted based on the Nationwide Inpatient Sample (NIS), enrolling patients who underwent TKR from 2010 to 2019 with complete information. The patients were divided into two groups based on whether they received blood transfusion or not. The demographic characteristics (race, sex, and age), length of stay (LOS), total charge of hospitalization, hospital characteristics (admission type, insurance type, bed size, teaching status, location, and region of hospital), hospital mortality, comorbidities, and perioperative complications were analyzed. Finally, we conducted univariate and multivariate logistic regression to identify factors that were associated with TKR patients to require blood transfusion.

RESULTS

The NIS database included 115,072 patients who underwent TKR. Among them, 14,899 patients received blood transfusion, and the incidence of blood transfusion was 13.0%. There was a dramatic decrease in the incidence over the years from 2010 to 2019, dropping from 20.4 to 6.5%. TKR patients requiring transfusions had experienced longer LOS, incurred higher total medical expenses, utilized Medicare more frequently, and had increased in-hospital mortality rates (all P < 0.001). Independent predictors for blood transfusion included advanced age, female gender, iron-deficiency anemia, rheumatoid disease, chronic blood loss anemia, congestive heart failure, coagulopathy, uncomplicated diabetes, lymphoma, fluid and electrolyte disorders, metastatic carcinoma, other neurological diseases, paralysis, peripheral vascular disorders, pulmonary circulation disorders, renal failure, valvular disease, and weight loss. In addition, risk factors for transfusion in TKR surgery included sepsis, acute myocardial infarction, deep vein thrombosis, pulmonary embolism, gastrointestinal bleeding, heart failure, renal insufficiency, pneumonia, wound infection, lower limb nerve injury, hemorrhage/seroma/hematoma, wound rupture/non healing, urinary tract infection, acute renal failure, and postoperative delirium.

CONCLUSIONS

Our findings highlight the importance of recognizing the risk factors of blood transfusion in TKR to reduce the occurrence of adverse events.

Potential value of a rapid syndromic multiplex PCR for the diagnosis of native and prosthetic joint infections: a real-world evidence study

Introduction: The BIOFIRE Joint Infection (JI) Panel is a diagnostic tool that uses multiplex-PCR testing to detect microorganisms in synovial fluid specimens from patients suspected of having septic arthritis (SA) on native joints or prosthetic joint infections (PJIs). Methods: A study was conducted across 34 clinical sites in 19 European and Middle Eastern countries from March 2021 to June 2022 to assess the effectiveness of the BIOFIRE JI Panel. Results: A total of 1527 samples were collected from patients suspected of SA or PJI, with an overall agreement of 88.4 % and 85 % respectively between the JI Panel and synovial fluid cultures (SFCs). The JI Panel detected more positive samples and microorganisms than SFC, with a notable difference on Staphylococcus aureus, Streptococcus species, Enterococcus faecalis, Kingella kingae, Neisseria gonorrhoeae, and anaerobic bacteria. The study found that the BIOFIRE JI Panel has a high utility in the real-world clinical setting for suspected SA and PJI, providing diagnostic results in approximately 1 h. The user experience was positive, implying a potential benefit of rapidity of results' turnover in optimising patient management strategies. Conclusion: The study suggests that the BIOFIRE JI Panel could potentially optimise patient management and antimicrobial therapy, thus highlighting its importance in the clinical setting.

Debridement, antibiotics, and implant retention (DAIR) for the early prosthetic joint infection of total knee and hip arthroplasties: a systematic review

PURPOSE

Early periprosthetic joint infection (PJI) represents one of the most fearsome complications of joint replacement. No international consensus has been reached regarding the best approach for early prosthetic knee and hip infections. The aim of this updated systematic review is to assess whether debridement, antibiotics, and implant retention (DAIR) is an effective choice of treatment in early postoperative and acute hematogenous PJI.

METHODS

This systematic review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. The diagnostic criteria defining a PJI, the most present pathogen, and the days between the index procedure and the onset of the PJI were extracted from the selected articles. Additionally, the mean follow-up, antibiotic regimen, and success rate of the treatment were also reported.

RESULTS

The articles included provided a cohort of 970 patients. Ten studies specified the joint of their cohort in PJIs regarding either hip prostheses or knee prostheses, resulting in 454 total knees and 460 total hips. The age of the patients ranged from 18 to 92 years old. Success rates for the DAIR treatments in the following cohort ranged from 55.5% up to a maximum of 90% (mean value of 71%).

CONCLUSION

Even though the DAIR procedure is quite limited, it is still considered an effective option for patients developing an early post-operative or acute hematogenous PJI. However, there is a lack of studies, in particular randomized control trials (RCTs), comparing DAIR with one-stage and two-stage revision protocols in the setting of early PJIs, reflecting the necessity to conduct further high-quality studies to face the burden of early PJI.

Etiology of Total Knee Arthroplasty Revisions: A Two-Decade Institutional Perspective

Total knee arthroplasty (TKA) implant survival time is determined by various patient and implant-related factors and varies significantly in recent worldwide reports. In our study, we have included 247 TKA revisions in 203 patients performed in our hospital over the last 20 years. Multiple etiologies of revisions were identified and classified into 10 categories. Time to failure was analyzed with regard to etiology, patient demographics, and other relevant data. The overall average time to revision was 44.08 months (95% confidence interval (CI) between 33.34 and 49.82 months). Age at primary implant was negatively correlated with time to revision (hazard ratio (HR) = 1.0521 and 95% CI of HR = 1.0359 to 1.0685) and female patients showed a 1.59 times higher risk of implant failure than males. Periprosthetic joint infection was the cause of 46.56% (n=115) of revisions (out of which 12.55% (n=31) were early infections, diagnosed within the first three months), while aseptic loosening was found in 31.98% (n=79) of cases. Infection correlated with a shorter time to revision compared to aseptic loosening (p<0.05). These findings emphasize the need to intensify efforts to deliver the best patient care, select the best antibiotic regimen, and improve surgical techniques to decrease the incidence of infectious complications.

Global mapping of institutional and hospital-based (Level II-IV) arthroplasty registries: a scoping review

PURPOSE

Four joint arthroplasty registries (JARs) levels exist based on the recorded data type. Level I JARs are national registries that record primary data. Hospital or institutional JARs (Level II-IV) document further data (patient-reported outcomes, demographic, radiographic). A worldwide list of Level II-IV JARs must be created to effectively assess and categorize these data.

METHODS

Our study is a systematic scoping review that followed the PRISMA guidelines and included 648 studies. Based on their publications, the study aimed to map the existing Level II-IV JARs worldwide. The secondary aim was to record their lifetime, publications' number and frequency and recognise differences with national JARs.

RESULTS

One hundred five Level II-IV JARs were identified. Forty-eight hospital-based, 45 institutional, and 12 regional JARs. Fifty JARs were found in America, 39 in Europe, nine in Asia, six in Oceania and one in Africa. They have published 485 cohorts, 91 case-series, 49 case-control, nine cross-sectional studies, eight registry protocols and six randomized trials. Most cohort studies were retrospective. Twenty-three per cent of papers studied patient-reported outcomes, 21.45% surgical complications, 13.73% postoperative clinical and 5.25% radiographic outcomes, and 11.88% were survival analyses. Forty-four JARs have published only one paper. Level I JARs primarily publish implant revision risk annual reports, while Level IV JARs collect comprehensive data to conduct retrospective cohort studies.

CONCLUSIONS

This is the first study mapping all Level II-IV JARs worldwide. Most JARs are found in Europe and America, reporting on retrospective cohorts, but only a few report on studies systematically.

Outcomes After Successful Debridement, Antibiotic, and Implant Retention Therapy for Periprosthetic Joint Infection in Total Knee Arthroplasty

BACKGROUND

Controversy surrounds debridement, antibiotic and implant retention (DAIR) for treatment of acute periprosthetic joint infection (PJI). Data regarding DAIR's rate of infection resolution is variable with little investigation of functional outcomes.

METHODS

We identified 191 DAIR cases at a single institution from 2008 to 2020. Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR) and Patient Reported Outcome Measurement Information System-10 (PROMIS) scores were collected. Patient Reported Outcome Scores were obtained from 60 cases. Median follow-up (IQR) was 4.5 (2.1 to 7.6) versus 3.0 (1.2 to 5.3) years for the control group. Mean scores were compared to a cohort of uncomplicated total knee arthroplasties matched by age, body mass index, and sex using generalized linear models adjusted for follow-up duration. Kaplan-Meier survivorship curves for PJI were constructed.

RESULTS

Mean Patient Reported Outcome Scores for the DAIR cohort were 57.2 ± 19.7 for KOOS-JR, 41.6 ± 7.1 for PROMIS physical health (PH), and 46.6 ± 8.7 for PROMIS mental health (MH). Mean control group values were 65.8 ± 21.0 for KOOS-JR, 44.6 ± 8.4 for PROMIS PH, and 49.2 ± 9.2 for PROMIS MH. No difference was observed in KOOS-JR (P = .83) or PROMIS MH (P = .11). PROMIS PH was lower in the DAIR cohort compared to the control group (P = .048). Median follow-up (years) for all 191 cases was 5.9 (range, 0.5 to 13.1). Survivorship (years) without subsequent operation for infection was 84% at 1, 82% at 2, and 79% at 5.

CONCLUSION

Knee and MH outcomes in successful DAIR procedures were similar to uncomplicated total knee arthroplasty. DAIR's success rate was 79% in treating acute PJI at 5 years.

LEVEL OF EVIDENCE

Level III.

Complications of Bicruciate-Retaining Total Knee Arthroplasty: The Importance of Alignment and Balance

Bicruciate-retaining total knee arthroplasty (BCR TKA) results in kinematics closer to the native knee and in greater patient satisfaction but information concerning its outcome and complications is lacking.The goal of this study is to report the clinical and radiological outcomes of BCR prosthesis implanted using a spacer-based gap balancing technique and to assess if some preoperative factors are associated with a worse prognosis.A cohort of 207 knees in 194 patients who underwent BCR TKA, with a minimum 1-year follow-up, was retrospectively analyzed.Patients were followed at 6 weeks, 6 months, 1 year, and then every following year postoperatively, and filled questionnaires (Knee Society and Knee injury and Osteoarthritis Outcome Score) at every visit. Clinical and radiological assessments included range of motion, knee alignment, pain, and complications as defined by the Knee Society's Standardized list and definition of Complication of Total Knee Arthroplasty.Forty-three knees (20.8%) suffered major complications. Twenty-one knees (10.1%) underwent revision at an average of 32.1 months after the index procedure. Revision-free survival at 100 months was 85.7%. Revision was performed for aseptic tibial loosening in eight knees (3.9%) and stiffness in five knees (2.4%). There were 29 reoperations other than revision (14.0%), the most frequent procedure being manipulation under anesthesia in 14 knees (6.8%). Minor complications included tendonitis (20.8%), persistent synovitis (6.8%), and superficial wound infections (6.3%).All outcomes scores were greatly improved at the 1-year follow-up compared with preoperatively (p < 0.001). However, maximum flexion at the last follow-up was significantly reduced compared with preoperatively (mean maximum flexion ± standard deviation: 119.9 ± 15.6 vs. 129.9 ± 14.4, p < 0.001). Aseptic tibial loosening was associated with a hypercorrection in varus of preoperative valgus knees (p = 0.012).BCR TKA can give functional results similar to other types of prostheses but involves a substantial risk of complications. Important factors that can explain failed BCR TKA and guide its use were identified, more particularly knee alignment and its role in aseptic tibial loosening.

Leg length discrepancy before total knee arthroplasty is associated with increased complications and earlier time to revision

INTRODUCTION

Leg length discrepancy (LLD) following total knee arthroplasty (TKA) is a common complaint, leading to decreased patient satisfaction. However, the effect of LLD diagnosis prior to TKA on outcomes and complications is not well defined. Thus, this study aimed to assess the effects that LLD has on rates of falls and implant complications, length of stay and readmissions, and implant survivorship following TKA.

METHODS

A retrospective review of a private insurance claims database was conducted from 2010 to 2021. All cases of TKA and those with a diagnosis of leg length discrepancy were identified. Patients undergoing TKA with a diagnosis of LLD were matched to control patients 1:5 based on demographic and comorbidity profiles. Two-year fall rates and implant complications, lengths of stay, 90-day readmissions, and time to revision were compared between cohorts.

RESULTS

A total of 1,378 LLD patients were matched to 6,889 control patients. The LLD group had significantly higher rates of falls, dislocation, mechanical loosening, periprosthetic fracture, and fibrosis when compared to the control group (all P < 0.01). Additionally, mean length of stay was significantly greater in the LLD group (4.9 days vs. 3.0 days, P < 0.001). There was no significant difference in 90-day readmission rates between groups (P = 0.178). Time to revision was significantly shorter in the LLD group (392 days vs. 928 days, P < 0.001).

CONCLUSIONS

Leg length discrepancy in patients undergoing TKA was associated with significantly increased fall risk, rates of implant complications, length of stay, and faster time to revision. The findings of this study may allow orthopedic surgeons to identify those patients at risk and allow for more educated patient counseling and operative planning.

LEVEL OF EVIDENCE

III, retrospective case-control study.

Meta-analysis of outcomes after total knee arthroplasty in patients with rheumatoid arthritis and osteoarthritis

The purpose of this study was to compare the difference in functional scores and the incidence of complications after TKA between RA and osteoarthritis. The PubMed, MedLine, The Cochrane Library, Embase and Web of Science databases were searched for all clinical studies up to 15 March 2023 comparing outcomes after total knee replacement in patients with RA and OA, with two review authors independently screening the literature. A total of 7,820,115 (knee-counted) cases were included in 34 studies. The results of meta-analysis showed that the scores of the RA group were lower than that of the osteoarthritis group in the postoperative knee joint score [MD=-2.72,95%CI(-5.06,-0.38),P=0.02] and the postoperative knee joint function score [MD=-11.47,95%CI(-16.55,-6.39),P<0.00001], and the difference was statistically significant. The incidence of deep venous thrombosis (OR=0.84,95%CI(0.79,0.90),P<0.00001) and pulmonary embolism (OR=0.84,95%CI(0.78,0.91),P<0.00001) were significantly lower in RA than in osteoarthritis (P<0.00001). Compared with patients with osteoarthritis, patients with rheumatoid arthritis have lower knee society scores and functional scores after total knee arthroplasty, and a higher risk of prosthetic infection, loosening, and revision, but TKA can still effectively reduce pain in RA patients, Improve function and quality of life without increasing the risk of lower extremity venous thrombosis and pulmonary embolism. Therefore, total knee replacement can be used as a treatment option for patients with rheumatoid arthritis who have not responded to conservative treatment. Patients should fully understand the benefits and possible risks of total knee replacement and develop an individualized treatment plan.

The Role of Genicular Radiofrequency Ablation in the Management of Persistent Pain after Total Knee Arthroplasty

Persistent pain is one of the most frequent complications following total knee arthroplasty (TKA) and can be devastating for the patient's quality of life. The use of genicular nerve radiofrequency ablation (GNRFA) is prevalent regarding non-surgical treatment of knee osteoarthritis. However, it is controversial when employed for the management of residual pain after TKA. This study aims to evaluate the efficacy of GNRFA for the treatment of post-TKA chronic pain and to assess the potential benefits of its use. Twelve patients sustaining chronic pain after TKA underwent GNRFA treatment. The intervention included the superior medial genicular nerve, the superior lateral genicular nerve and the inferior medial genicular nerve. Visual analog scale (VAS) system was utilized for pain assessment at 1-week, 6-month, and 1-year follow-ups. Patients experiencing chronic knee pain derived from other or unspecified causes were excluded. Mean VAS score before the treatment was 8.3, while it ended up 2.3, 5.7, and 7.9 at the 1-week, 6-month, and 1-year follow-up, respectively. Some patients reported residual pain that they regarded more bearable than before the procedure at the 1-week evaluation, with no significant alterations in the 6-month reassessment. In 2 cases results at the 1-week follow-up were dissatisfying, however, this aided us in distinguishing the cause of the persistent pain. We were not able to conclude that GNRFA used for the treatment of chronic pain after TKA is as efficacious as in knee osteoarthritis pain. However, in some cases, it proved to be beneficial regarding discerning the etiology of the pain.

Physical activity and health-related quality of life of patients with chronic knee pain after total knee replacement: Analysis of the PEP-TALK trial

BACKGROUND

Chronic pain is a major challenge for some people after total knee replacement (TKR). The changing impact of this complication during the first post-operative year remains unclear. This analysis aimed to examine how physical activity and health-related quality of life (HRQoL) evolved over the first year after TKR for patients with and without post-operative chronic knee pain.

METHODS

We conducted a secondary analysis of data from a randomised controlled trial (PEP-TALK), which tested the effectiveness of a behaviour change physiotherapy intervention compared with usual rehabilitation after TKR. Mean UCLA Activity Score and EQ-5D-5L for participants with and without chronic knee pain (14 points or lower in the Oxford Knee Score Pain Subscale (OKS-PS) at six months post-TKR) were compared at six and 12 months post-TKR.

RESULTS

Data from 83 participants were analysed. For those with chronic knee pain, UCLA Activity Score remained unchanged between baseline to six months (mean: 3.8 to 3.8), decreasing at 12 months (3.0). Those without post-operative chronic knee pain reported improved physical activity from baseline to six months (4.0 vs 4.9), plateauing at 12 months (4.9). Participants with chronic knee pain reported lower baseline HRQoL (0.28 vs 0.48). Both groups improved health utility over one year. Of those without chronic pain at six months, 8.5% returned to chronic pain by 12 months.

CONCLUSIONS

Monitoring clinical outcomes after six months may be indicated for those at risk of chronic pain post-TKR. Further, sufficiently powered analyses are warranted to increase the generalisability of this exploratory analyses' results.

The Effect of Povidone-Iodine Irrigation on the Efficacy of Antibiotic Cement In Vitro

Povidone-iodine is a common antiseptic demonstrating success in reducing infection rates in primary arthroplasty; however, recent data suggest that its use in revision arthroplasty may increase infection rates. This study evaluated the effect of povidone-iodine solution on antibiotic cement and investigated the connection between povidone-iodine and increased infection rates in revision arthroplasty. Sixty antibiotic cement samples (ACSs) were formed using gentamicin-impregnated cement. The ACSs were divided into three groups: group A (n=20) was subject to a 3-minute povidone-iodine soak followed by a saline rinse; group B (n=20) underwent a 3-minute saline soak; and group C (n=20) underwent only a saline rinse. The antimicrobial activity of the samples was tested using a Kirby-Bauer-like assay using Staphylococcus epidermidis. The zone of inhibition (ZOI) was measured every 24 hours for 7 days. All groups possessed the greatest antimicrobial activity at 24 hours. Group C displayed a mass-corrected ZOI of 395.2 mm/g, which was statistically greater than the group B ZOI (313.2 mm/g, P<.05) but not the group A ZOI (346.5 mm/g, P>.05). All groups demonstrated a decrease in antimicrobial activity at 48 through 96 hours, with no significant difference at any time point. Prolonged soaking of antibiotic cement in a povidone-iodine or saline solution results in elution of the antibiotic into the irrigation solution, blunting initial antibiotic concentration. When using antibiotic cement, antiseptic soaks or irrigation should be focused prior to cementation. [Orthopedics. 2024;47(1):10-14.].