Metaphyseal cones and sleeves are similar in improving short- and mid-term outcomes in Total Knee Arthroplasty revisions

Metaphyseal Fixation in Revision Total Knee Arthroplasty

➢ Bone defect management is challenging, but essential, in revision total knee arthroplasty.➢ Appropriate metaphyseal fixation is crucial for stability and implant support.➢ Allografts have been traditionally used to address large defects, but the advent of highly porous metaphyseal cones and sleeves has attracted attention during the past years.➢ Metaphyseal implants are now available in a variety of shapes and sizes to meet various clinical needs.➢ These devices can successfully fill large defects, can better support revision implants, and can achieve long-term biologic fixation.➢ Very good intermediate-term outcomes have been reported with the available metaphyseal implants, using fully cemented or press-fit stems.➢ More research is warranted to further assess surgical indications and the strengths and weaknesses of the various implants used for metaphyseal fixation.

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.

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.

Artificial intelligence in total and unicompartmental knee arthroplasty

The application of Artificial intelligence (AI) and machine learning (ML) tools in total (TKA) and unicompartmental knee arthroplasty (UKA) emerges with the potential to improve patient-centered decision-making and outcome prediction in orthopedics, as ML algorithms can generate patient-specific risk models. This review aims to evaluate the potential of the application of AI/ML models in the prediction of TKA outcomes and the identification of populations at risk.An extensive search in the following databases: MEDLINE, Scopus, Cinahl, Google Scholar, and EMBASE was conducted using the PIOS approach to formulate the research question. The PRISMA guideline was used for reporting the evidence of the data extracted. A modified eight-item MINORS checklist was employed for the quality assessment. The databases were screened from the inception to June 2022.Forty-four out of the 542 initially selected articles were eligible for the data analysis; 5 further articles were identified and added to the review from the PUBMED database, for a total of 49 articles included. A total of 2,595,780 patients were identified, with an overall average age of the patients of 70.2 years ± 7.9 years old. The five most common AI/ML models identified in the selected articles were: RF, in 38.77% of studies; GBM, in 36.73% of studies; ANN in 34.7% of articles; LR, in 32.65%; SVM in 26.53% of articles.This systematic review evaluated the possible uses of AI/ML models in TKA, highlighting their potential to lead to more accurate predictions, less time-consuming data processing, and improved decision-making, all while minimizing user input bias to provide risk-based patient-specific care.

Excellent mid- to long-term survival of tantalum metal cones in a case series of revision knee arthroplasty with severe bony defects

PURPOSE

Severe metaphyseal bone defects remain a challenge and represent a growing problem in revision total knee arthroplasty (RTKA). The purpose of this study was to examine the survival of first-generation tantalum metal cones (TMC) and to assess clinical and radiographic data obtained from mid- to long-term follow-ups (FU) after RTKA with severe bony defects.

METHODS

This retrospective case series included 100 consecutive patients of the same centre, who underwent RTKA surgery with TMC for tibia and/or femur bone defects between January 2011 and December 2015. Fourteen patients had died and six were lost for FU, leaving a total of eighty patients (one hundred and twelve TMC) for final evaluation. Clinical parameters including the Knee Society Score (KSS), visual analogue scale (VAS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and range of motion (ROM) were determined preoperatively based on the patients' medical charts, and assessed again during the final FU after an average of 6.1 (5-9) years postoperative. Standardised postoperative X-rays were analysed during the final FU visit for osseointegration of the cones, and any signs of implant loosening were assessed with the modified Knee Society Radiographic review criteria. Perioperative and postoperative complications, reoperations, as well as implant and cone re-revisions were analysed. Survivorship analysis was performed with (a) cone-related revision for any reason and (b) implant component revision for any reason.

RESULTS

Previous RTKA had to be performed due to 64 (80%) aseptic and 16 (20%) septic failures. At the final FU, 75 (94%) tibia and 76 (95%) femur TMCs and implants were clinically stable. One patient experienced loosening of cones and implants at the femur and tibia but denied re-revision surgery. There were eight (10%) reoperations including two early wound healing problems, two inlay changes, two periprosthetic fractures, one debridement, antibiotics and implant retention (DAIR), and one secondary patella replacement. The six (7.5%) re-revisions included two aseptic loosening's of the opposite implant without TMC, one arthrodesis for recurrent instability, and three deep infections managed by two two-stage exchanges, and one amputation for persistent infection. At re-revision, all TMC cones were osteointegrated without signs of loosening. The determined clinical parameters showed significant (p < 0.001) postoperative improvement, and objective KSS was rated as excellent in 51%, and as good in 22% of patients at the final FU. The estimated 8-year Kaplan-Meier survival was 95% for TMC and 92.5% for implant components.

CONCLUSION

Tantalum metal cones (TMC) demonstrate a secure fixation for treatment of severe femoral and tibial metaphyseal bone defects during RTKA. This fixation concept showed excellent mid- to long-term clinical and radiographic outcomes with promising 8-year survival rates for cones and implant components.

LEVEL OF EVIDENCE

Retrospective cohort study, Level IV.

Metaphyseal Metal Sleeves for Reconstruction of Severe Knee Bone Defects: Excellent Survival Rate at a Mean Follow-Up of 6.4 Years

OBJECTIVE

Management of bone loss in complex primary and revision total knee arthroplasty is key to the surgeries. Metaphyseal metal sleeves have been increasingly used recently to reconstruct severe knee metaphyseal bone defects. This study aimed to investigate the outcomes of the metaphyseal sleeve reconstructing Anderson Orthopedic Research Institute (AORI) type II and type III bone defects of knee joint.

METHODS

From 2014 to 2019, a total of 44 knees were enrolled in this clinical retrospective study after the screening, including seven cases of primary TKA and 37 cases of revision TKA. The types of bone defects involved in this study were AORI types II and III, and did not involve AORI type I bone defects. Patients' knee function preoperatively and postoperatively as well as quality of life were recorded and analyzed. Analysis included the American Knee Society Score (KSS), hospital for special surgery knee score (HSS), the Western Ontario and McMaster Universities (WOMAC) index, the Short Form 12 (SF-12) health survey, visual analogue scale score, and radiographic assessment with a mean follow-up of 6.4 years. Paired t-tests were used to determine the significance of changes in clinical scores and knee mobility.

RESULTS

A mean follow-up of 77.2 (±17.6, standard deviation [SD]) months was performed, and none of the patients underwent knee revision for infection or aseptic loosening. At the last follow-up, the KSS knee score changed statistically from 37.1 (±19.7) preoperatively to 86.5 (±13.6, SD, p < 0.001) postoperatively and the KSS function score from 32.7 (±24.0) preoperatively to 78.3 (±15.6, SD, p < 0.001) postoperatively. The knee mobility improved from a mean of preoperative 72.61° (±33.42°, SD) to 108.52° (±24.15°, SD, p < 0.001). Postoperative radiographs showed that the host bone was tightly integrated with the metaphyseal metal sleeve, and there was no obvious translucent line formation around the sleeve. Of the patients, 86.4% had a postoperative satisfaction score ≥8 (10-point scale).

CONCLUSION

At the mean follow-up of 6.4 years, the survival rate of the metaphyseal sleeves was 100%. Metaphyseal sleeves combined with cementless stems is an excellent and viable option for reconstruction of AORI type II and type III bone defects of the knee.