Clinical and economic burden of revision knee arthroplasty

Causative factors for varus tibial baseplate subsidence in primary total knee arthroplasty: A retrospective analysis

Background

In this retrospective study, the focus was on identifying potential causative factors associated with varus subsidence of the tibial component in primary total knee arthroplasty (TKA). The research aimed to investigate the risk factors contributing to aseptic varus tibial baseplate subsidence (VTBS) leading to revision TKA procedures.

Patients and methods

A total of 120 patients with documented VTBS complications post-TKA were compared with a control group of 52 patients. Factors such as patient demographics, surgical data and comorbidities were included. The study also explored the Coronal Plane Alignment of the Knee (CPAK) classification pre- and post-operatively to understand its implications on varus subsidence.

Results

Significant differences noted in the VTBS group in variables including younger patient age (P=<0.001), increased BMI (P = 0.003), larger proportion of patients with tibial component oversize or undersizing (P=<0.001), less tibial stem extensions used (P < 0.001), higher CCI (P < 0.001) and a higher proportion of patients in CPAK group 2 (P = 0.044).

Conclusion

This investigation provides valuable insights into potential risk factors for VTBS, aiming to optimize patient outcomes and assist in preventing complications associated with TKA procedures.

Characterizing the Cost Trends of Readmissions After Aseptic Revision Total Knee Arthroplasty

BACKGROUND

A rise in total knee arthroplasty (TKA) volume has led to an increased incidence of aseptic revision TKA (rTKA), resulting in major associated health care costs. This study evaluated the economic impact and clinical factors associated with readmission following aseptic rTKA, aiming to identify key drivers of cost and risk factors for readmission.

METHODS

This retrospective analysis used data from a large national database from January 1, 2009, to June 30, 2022. Patients undergoing aseptic rTKA were identified via Current Procedural Terminology codes. Readmissions within 90 days postoperatively were analyzed. Baseline characteristics, comorbidities, and readmission costs were compared, and significant risk factors for readmission were identified. Of 34,144 aseptic rTKA patients, 1,953 (5.7%) were readmitted within 90 days (56.1% medical, 29.2% surgical, and 14.8% unknown).

RESULTS

The median cost of all readmissions was $25,181. Readmissions requiring reoperation had a higher cost (median $40,524 versus $20,907, P < 0.001). Among readmissions for surgical complications, periprosthetic joint infection was the most common cause (36.3%) and was associated with the greatest cost (median $38,104). The most common medical causes of readmission were rehabilitative care, ischemic cardiac events, and acute kidney injury. Significant risk factors for all-cause readmission included men, index revision for periprosthetic fracture, and comorbidities, including diabetes, coronary artery disease, renal disease, and congestive heart failure.

CONCLUSIONS

Readmission after aseptic rTKA results in a major economic burden to the health care system, particularly in readmission pertaining to surgical complications and requiring reoperation. This study highlights the need for targeted strategies aimed at effectively reducing the rate and costs associated with readmission post-rTKA with a goal of cost containment and improved patient outcomes.

Repeat Two-Stage Exchange Arthroplasty for Recurrent Periprosthetic Knee Infection: Results of 87 Cases

BACKGROUND

Despite the success of two-stage exchange total knee arthroplasties (TKAs), a subset of patients become reinfected and may be considered for a repeat two-stage exchange TKAs. A small, prior study from our institution demonstrated a 50% re-revision rate in such a cohort. The purpose of the present study was to evaluate a contemporary and larger cohort of repeat two-stage exchange TKAs with an emphasis on implant survivorship, risk factors, and clinical outcomes.

METHODS

We retrospectively identified 87 repeat two-stage exchange TKAs performed between 2014 and 2021. The mean patient age was 66 years, 32% were women, and the mean body mass index was 29. At the time of resection, 98% of patients were treated with a high-dose antibiotic spacer (58 nonarticulating and 27 articulating). The mean time from resection arthroplasty to reimplantation was 22 weeks. Kaplan-Meier survivorship analyses were performed, and risk factors (including the McPherson staging system) were assessed. The mean follow-up was five years (range, two to nine).

RESULTS

The 5-year survivorships free of rerevision for reinfection, any rerevision, and any reoperation were 88, 67, and 54%, respectively. Leading causes for rerevision were periprosthetic joint infection (36%) and aseptic loosening (27%). There were no statistically significant independent risk factors identified. However, patients who had McPherson host grade C trended toward higher rates of reoperation (hazard ratio: 2, P = 0.057). Despite the high reoperation rate, at the final follow-up (mean five years), 91% of patients had a TKA in situ, 8% had been treated with above-knee amputation, and 1% with a definitive resection arthroplasty.

CONCLUSIONS

Despite its challenges, including a 54% reoperation rate, repeat two-stage exchange TKAs may be considered in a subset of patients given 91% of patients had a TKA in situ at a mean of five years, and the 5-year survivorship free of rerevision for infection was 88%. Notably, patients who were McPherson host grade C trended toward failure.

LEVEL OF EVIDENCE

Level IV.

Revision Total Knee Arthroplasty Achieves Minimal Clinically Important Difference Faster Than Primary Total Knee Arthroplasty

BACKGROUND

Revision total knee arthroplasty (rTKA) remains underexplored regarding patient-reported outcome measures (PROMs), particularly in terms of time to reach minimal clinically important difference (MCID). This study addresses this gap by comparing the time to achieve MCID between primary TKA (pTKA) and rTKA patients, providing valuable insights into their recovery trajectories.

METHODS

A total of 8,266 TKAs (7,618 pTKA and 648 rTKA) were retrospectively studied in a multi-institutional arthroplasty registry. Patients who completed the patient-reported outcomes measurement information system (PROMIS) global physical, PROMIS physical function short form 10a (PF-10a), and knee injury and osteoarthritis outcome score physical function short form (KOOS-PS) questionnaires were identified by Current Procedural Terminology codes. Survival curves with and without interval censoring were utilized to evaluate the time to achieve MCID.

RESULTS

Comparing the time to achieve MCID, rTKAs were significantly faster than pTKA for PROMIS global physical (3.5 versus 3.7 months, P = 0.004) and KOOS-PS (3.3 versus 4.2 months, P < 0.001), but similar for PROMIS PF-10a (4.4 versus 4.8 months, P = 0.057). Interval censoring also showed similar trends with earlier times to achieve MCID for rTKAs for PROMIS global physical (0.6 to 0.61 versus 0.97 to 0.97 months, P = 0.009) and KOOS-PS (0.97 to 0.97 versus 1.47 to 1.47 months, P < 0.001), but not for PROMIS PF-10a (2.43 to 2.54 versus 1.90 to 1.91 months, P = 0.92).

CONCLUSIONS

The present study revealed that the time to achieve MCID was faster in patients undergoing rTKA compared to those undergoing pTKA. These findings allow surgeons to reassure preoperative rTKA patients that their recovery to a MCID postoperatively may be quicker than expected, especially when compared to their initial recovery after primary TKA.

LEVEL OF EVIDENCE

Level III.

EMMATKA trial: the effects of mobilization with movement following total knee arthroplasty in women: a single-blind randomized controlled trial

BACKGROUND

Mobilization with Movement (MWM) is an examination and management approach for correcting the intra-articular translational and rotational movements to facilitate the active physiological movement. The study aimed to determine the effects of MWM on Total Knee Arthroplasty (TKA) using a randomized controlled trial (RCT) design.

METHODS

The trial is registered (ISRCTN ref: 13,028,992). A blinded examiner assessed patients at pre-surgical (before TKA), post-surgical (at 3-weeks post-TKA), 6-weeks and 6-months post-TKA. Participants were randomly assigned to receive MWM (six sessions, between 3 and 6 weeks post-TKA) plus standard rehabilitation (intervention group) or standard rehabilitation alone (control group) of outpatient rehabilitation including range of motion and strengthening exercises, cycling, gait and stair training. Outcome measures were range of motion (goniometer), pain (visual analogue scales), physical function (Timed Up and Go (TUG)), a 15-m walk test, and health status (Western Ontario and McMaster (WOMAC) Osteoarthritis Index). Change in outcome measures from post-surgical to 6 weeks and 6 months post-TKA were compared between groups. The primary outcome was change in knee flexion range of motion at 6 weeks.

RESULTS

84 women scheduled for TKA were randomly allocated to intervention (n = 42) or control (n = 42); mean ± (SD) age 65.1 ± 7.4 and 66.8 ± 8.9 years, respectively. The intervention group demonstrated significantly greater increase in knee flexion at both 6 weeks (median (IQR) + 10.000 (20.000) compared with + 2.500 (6.250) in the control group) and 6 months (+ 12.500 (15.000) and + 5.000 (10.000) respectively) (both p < 0.05). There were no differences between groups in secondary outcomes.

CONCLUSION

Introducing MWM for TKA rehabilitation has greater benefits for women post-TKA in increasing knee joint flexion range of motion than the standard rehabilitation programs in the short and medium-term. This evidence-based approach offers a promising adjunctive intervention for optimizing recovery and rehabilitation process following TKA in women. Clinicians should consider including MWM approach in post-TKA rehabilitation programs.

LEVEL OF EVIDENCE

I.

Periprosthetic Joint Infection: Are Patients Still Better off Than if Primary Arthroplasty Had Not Been Performed?

BACKGROUND

This study sought to evaluate patient-reported outcome measures (PROMs) before primary total joint arthroplasty (TJA) and after successful treatment for periprosthetic joint infection (PJI), with the hypothesis that patients still demonstrate clinical improvement despite the occurrence of PJI.

METHODS

A single tertiary academic center's institutional database was retrospectively reviewed for patients who underwent primary TJA, developed PJI, and were managed for PJI from January 2019 to December 2023. Patients who did not have PROMs recorded were excluded from the study. Preoperative and postoperative generic and joint-specific PROMs were collected. Patient preprimary and postfinal revision surgery for PJI PROMs were subsequently compared. The minimum follow-up after PJI treatment was 6 months. A total of 55 patients (31 total knee arthroplasty and 24 total hip arthroplasty) were included with a mean follow-up of 1.8 years (range, 6 months to 4.5 years). All PJIs were managed via debridement, antibiotics, and implant retention, 1-stage, 1.5-stage, 2-stage revision, or resection arthroplasty.

RESULTS

After final revision surgery for PJI in total knee arthroplasty, patients had lower median patient-reported outcome measure information system (PROMIS) pain interference scores than before their primary surgery (62.0 [55.0, 67.0] versus 67.0 [65.0, 70.5]; P < 0.01). However, median PROMIS physical function postfinal revision for PJI and preprimary scores were similar (38.0 [33.0, 42.0] versus 34.0 [29.5, 40.0]; P = 0.08). After final revision surgery for PJI in total hip arthroplasty, patients had lower median PROMIS pain interference scores than before their primary surgery (57.5 [53.8, 64.0] versus 68.0 [66.5, 74.0]; P < 0.01). After final revision surgery for PJI, patients also had higher median PROMIS physical function scores than before their primary surgery (39.5 [33.5, 48.2] versus 29.5 [28.8, 34.2]; P < 0.01).

CONCLUSIONS

Patients who have been successfully managed for PJI show improvement in generic and joint-specific PROMs compared to their preprimary TJA PROMs.

Declining Trends in Septic Revision Following Total Knee Arthroplasty From 2010 to 2019: A National Cohort Analysis

BACKGROUND

Periprosthetic joint infections (PJIs) following total knee arthroplasty (TKA) are associated with high patient morbidity, mortality, and health care costs. Methods to reduce the burden of PJI have been shown to be efficacious on a small scale. On a national scale, it is unknown whether these methods have reduced PJI rates.

METHODS

A retrospective trend analysis was conducted using a national database. The incidence of 2-year septic revision was observed for the entire cohort in patients who had high-risk comorbidities from 2010 to 2019. A multivariable logistic regression was performed to compare the odds ratios of 2-year septic revision rates from 2011 to 2019 to the reference year of 2010. Linear regression was used to compare the change in the overall and high-risk subanalysis groups.

RESULTS

Among the 860,185 patients, 5,589 underwent septic revision within 2 years. The 2-year septic revision rate decreased from 0.75% in 2010 to 0.69% in 2019 (compounded annual growth rate = -0.94%, P = 0.049). Multivariable logistic regressions demonstrated that the odds of septic revision in 2019 were significantly lower than those in 2010 (odds ratio: 0.83, 95% CI [confidence interval]: [0.70 to 0.96], P = 0.017). In high-risk patients, the septic revision rate decreased from 1.04 to 0.80% (compounded annual growth rate = -2.80%, P = 0.004), specifically in those who had a history of psychoses, Medicaid insurance, anemia, heart failure, obesity, liver disease, tobacco use, and drug abuse (P < 0.05 for all).

CONCLUSIONS

This study demonstrated a national reduction in the 2-year septic revision rate in all TKA patients, including patients considered at high risk for PJI. This suggests that current preventative methods may be efficacious on a national scale in TKA. Further research is needed to identify more modalities to reduce the national incidence of this morbid and costly complication.

A novel concept of an acoustic ultrasound wearable for early detection of implant failure

Mechanical failure of medical implants, especially in orthopedic poses a significant burden to the patients and healthcare system. The majority of the implant failures are diagnosed at very late stages and are of mechanical causes. This makes the diagnosis and screening of implant failure very challenging. There have been several attempts for development of new implants and screening methods to address this issue; however, the majority of these methods focus on development of new implants or material and cannot satisfy the needs of the patients that have already been operated on. In this work we are introducing a novel screening method and investigate the feasibility of using low-intensity, low-frequency ultrasound acoustic waves for understanding of interfacial implant defects through computational simulation. In this method, we simultaneously apply and sense acoustic waves. COMSOL simulations proved the correlation between implant health condition, severity, and location of defects with measured acoustic signal. Moreover, we show that machine learning not only can detect and classify failure types, it can also assess the severity of the defects. We believe that this work can be used as a proof of concept to rationalize the development of non-invasive screening acoustic wearables for early detection of implant failure in patients with orthopedic implants.

Predicting prolonged length of stay following revision total knee arthroplasty: A national database analysis using machine learning models

BACKGROUND

As the number of revision total knee arthroplasty (TKA) continues to rise, close attention has been paid to factors influencing postoperative length of stay (LOS). The aim of this study is to develop generalizable machine learning (ML) algorithms to predict extended LOS following revision TKA using data from a national database.

METHODS

23,656 patients undergoing revision TKA between 2013 and 2020 were identified using the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database. Patients with missing data and those undergoing re-revision or conversion from unicompartmental knee arthroplasty were excluded. Four ML algorithms were applied and evaluated based on their (1) ability to distinguish between at-risk and not-at-risk patients, (2) accuracy, (3) calibration, and (4) clinical utility.

RESULTS

All four ML predictive algorithms demonstrated good accuracy, calibration, clinical utility, and discrimination, with all models achieving a similar area under the curve (AUC) (AUCLR=AUCRF=AUCHGB=0.75, AUCANN=0.74). The most important predictors of prolonged LOS were found to be operative time, preoperative diagnosis of sepsis, and body mass index (BMI).

CONCLUSIONS

ML models developed in this study demonstrated good performance in predicting extended LOS in patients undergoing revision TKA. Our findings highlight the importance of utilizing nationally representative patient data for model development. Prolonged operative time, preoperative sepsis, BMI, and elevated preoperative serum creatinine and BUN were noted to be significant predictors of prolonged LOS. Knowledge of these associations may aid with patient-specific preoperative planning, discharge planning, patient counseling, and cost containment with revision TKA.

Does interaction occur between risk factors for revision total knee arthroplasty?

INTRODUCTION

Several risk factors for revision TKA have previously been identified, but interactions between risk factors may occur and affect risk of revision. To our knowledge, such interactions have not been previously studied. As patients often exhibit multiple risk factors for revision, knowledge of these interactions can help improve risk stratification and patient education prior to TKA.

MATERIALS AND METHODS

The State Inpatient Databases (SID), part of the Healthcare Cost and Utilization Project (HCUP), were queried to identify patients who underwent TKA between January 1, 2006 and December 31, 2015. Risk factors for revision TKA were identified, and interactions between indication for TKA and other risk factors were analyzed.

RESULTS

Of 958,944 patients who underwent TKA, 33,550 (3.5%) underwent revision. Age, sex, race, length of stay, Elixhauser readmission score, urban/rural designation, and indication for TKA were significantly associated with revision (p < 0.05). Age was the strongest predictor (p  < 0.0001), with younger patients exhibiting higher revision risk. Risks associated with age were modified by an interaction with indication for TKA (p < 0.0001). There was no significant interaction between sex and indication for TKA (p = 0.535) or race and indication for TKA (p = 0.187).

CONCLUSIONS

Age, sex, race, length of stay, Elixhauser readmission score, urban/rural designation, and indication for TKA are significantly associated with revision TKA. Interaction occurs between age and indication.

Is Hospital-Based Outpatient Revision Total Knee Arthroplasty Safe? An Analysis of 2,171 Outpatient Aseptic Revision Procedures

BACKGROUND

Outpatient primary total knee arthroplasty (TKA) has been well-established as a safe and effective procedure; however, the safety of outpatient revision TKA remains unclear. Therefore, this study utilized a large database to compare outcomes between outpatient and inpatient revision TKA.

METHODS

An all-payor database was queried to identify patients undergoing revision TKA from 2010 to 2022. Patients who had diagnosis codes related to periprosthetic joint infection (PJI) were excluded. Outpatient surgery was defined as a length of stay < 24 hours. Cohorts were matched by age, sex, Elixhauser Comorbidity Index, comorbidities (diabetes, obesity, tobacco use), components revised (1-versus 2-component), and revision etiology. Medical complications at 90 days and surgical complications at 1 and 2 years postoperatively were evaluated through multivariate logistic regression. A total of 4,342 aseptic revision TKAs were included.

RESULTS

No differences in patient characteristics, procedure type, or revision etiologies were seen between groups. The outpatient cohort had a lower risk of PJI (odds ratio (OR): 0.547, 95% confidence interval (CI): 0.337 to 0.869; P = .012), wound dehiscence (OR: 0.393, 95% CI: 0.225 to 0.658; P < .001), transfusion (OR: 0.241, 95% CI: 0.055 to 0.750; P = .027), reoperation (OR: 0.508, 95% CI: 0.305 to 0.822; P = .007), and any complication (OR: 0.696, 95% CI: 0.584 to 0.829; P < .001) at 90 days postoperatively. At 1 year and 2 years postoperatively, outpatient revision TKA patients had a lower incidence of revision for PJI (OR: 0.332, 95% CI: 0.131 to 0.743; P = .011 and OR: 0.446, 95% CI; 0.217 to 0.859; P = .020, respectively) and all-cause revision (OR: 0.518, 95% CI: 0.377 to 0.706; P < .001 and OR: 0.548, 95% CI: 0.422 to 0.712; P < .001, respectively).

CONCLUSIONS

Our findings suggest that revision TKA can be safely performed on an outpatient basis in appropriately selected patients who do not have an increased risk of adverse events relative to inpatient revision TKA. However, we could not ascertain case complexity in either cohort, and despite controlling for several potential confounders, other less tangible differences could exist between groups.

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

Background

The rising number of total knee arthroplasty (TKA) replacements and their uncertain functional results according to the revision etiology and the prosthesis model implanted are a challenge for orthopedic surgeons and patients. A better knowledge of these results is mandatory to make the best decision. We present our clinical outcomes with a 5-year follow-up.

Methods

We retrospectively reviewed 104 patients, 108 knees (77 aseptic and 31 septic), who underwent TKA revision surgery from 2007 to 2017 with three different models of prosthesis. KSS score, range of motion (ROM), pain, and independence for walking were recorded at 5 years according to our own database and the clinical interview and compared to the different models of prosthesis and the etiology of the revision.

Results

The results showed 81.5 % of good or excellent functional outcomes in our patients with a mean KSS score of 76,7 ± 14,3, a mean ROM of 1.68 ± 0.30 radians, and 77 % of them are independent for walking without any aids. The results do not show any difference between the groups comparing the model of prosthesis and the etiology of the revision surgery.

Conclusions

At 5 years, TKA revision surgery offers good clinical and functional outcomes, independence for walking, good range of motion, and low residual pain regardless of the cause of the revision or the model of prosthesis.

Trends and Epidemiology in Revision Total Knee Arthroplasty: A Large Database Study

BACKGROUND

As the volume of primary total knee arthroplasty (TKA) continues to grow, the clinical and financial burden of revision total knee arthroplasty (rTKA) is expected to increase. The purpose of this investigation was to characterize contemporary indications and complications for rTKA.

METHODS

Patients undergoing rTKA between 2010 and 2021 were identified within an administrative claims database. Adjusted rTKA incidence was calculated by dividing the annual rTKA volume by the annual primary TKA and multiplying by 100,000. Mann-Kendall trend tests were utilized to trend revision volume, etiology, 90-day postoperative complications, and patient demographics.

RESULTS

A total of 397,367 rTKA were identified over our study period, of which 287,492 (72.4%) had coding regarding revision etiology. The volume of annual rTKA (31,091 to 33,850; P = 0.451) did not change over the study period. The adjusted incidence of rTKA decreased (25,568.3 to 19,272.2 per 100,000 annual TKA; P = 0.011). The leading causes of revision TKA were infection (21.2%), aseptic implant loosening (19.3%), and instability (9.8%). The rate of septic revision (4,710.5 to 4,426.1 per 100,000 annual TKAs) and aseptic implant loosening (4,502.5 to 3,636.4 per 100,000 annual TKAs) did not change (both P values > 0.05). The rates of instability increased (1,369.2 to 2,609.85 per 100,000 annual TKAs; P = 0.007). The rates of postrevision surgical site infection, periprosthetic joint infection, deep vein thrombosis, and transfusion decreased over the study period, while rates of emergency department visits and readmission increased (all P values <0.05).

CONCLUSIONS

The incidence of revision TKA may be slowing. While the risk of revision for infection and aseptic loosening remains unchanged, revision for instability has increased. The rates of postoperative complications appear to have decreased. Improved surgical technique, implant design, and perioperative protocols may have contributed to these findings. Continued work is necessary to reduce the risk of failure and postoperative complications.

The in-vivo medial and lateral collateral elongation correlated with knee functional score and joint space following unicompartmental knee arthroplasty

BACKGROUND

The medial collateral ligament (MCL) and lateral collateral ligament (LCL) are paramount for joint stability. Their elongation patterns may change during fixed-bearing and mobile-bearing unicompartmental knee arthroplasty (FB and MB UKA). This study aims to explore the relationship between the elongation of MCL, LCL, and changes in joint space, as well as their correlation with functional scale scores during FB and MB UKA.

HYPOTHESIS

We hypothesize that MCL and LCL have different elongation patterns in UKA patients, and there is a correlation between elongation and joint space and functional scores.

MATERIALS AND METHODS

The study recruited 24 patients undergoing UKA on a unilateral knee (13 FB and 11 MB). A dual fluoroscopic imaging system was employed to assess in-vivo knee kinematics during static standing and single-leg lunge. The superficial and deep MCL (sMCL, dMCL) and LCL were divided into anterior, medium, and posterior portions. The virtual ligament method quantified in-vivo ligament lengths. Analysis focused on the correlation of normalized ligament lengths with functional scores and joint space.

RESULTS

1. LCL Elongation in FB UKA: There is a significant increase in LCL elongation during early and mid-flexion of the single-leg lunge (p < 0.05). 2. MCL Elongation in MB UKA: Both sMCL and dMCL exhibit significant elongation during early and mid-flexion of the single-leg lunge (p < 0.05). 3. Correlation with Functional Scores: Differences in collateral ligament elongation in FB UKA are significantly correlated with the OKS and KSS, highlighting the impact on functional outcomes. In MB UKA, differences in ligament elongation are significantly correlated with the FJS. 4. Joint Space Correlation: There is a significant correlation between the elongation of the anterior and medium portions of dMCL and joint space in the surgical compartment during mid- and deep flexion (30-100°, p < 0.05, r > 0.64).

CONCLUSION

The study reveals distinct ligament elongation patterns between UKA and native knees in LCL for FB UKA and MCL for MB UKA. These patterns are associated with knee functional scores. Moreover, dMCL elongation correlates significantly with the joint space for MB UKA during middle and deep flexion phases.

LEVEL OF EVIDENCE

III; prospective retrospective cohort study.

Revision Total Knee Arthroplasty in an Outpatient Setting: A Growing Alternative

BACKGROUND

Recent studies have focused on the safety and efficacy of performing primary total knee arthroplasty (TKA) in an outpatient setting. Despite being associated with greater costs, much less is known about the accompanying impact on revision TKA (rTKA). The purpose of this study was to describe the trends in costs and outcomes of patients undergoing inpatient and outpatient rTKA.

METHODS

An observational cohort study was conducted using commercial claims databases. Patients who underwent 1-component and 2-component rTKA in an inpatient setting, hospital outpatient department (HOPD), or ambulatory surgery center (ASC) from 2018 to 2020 were included. The primary outcome was the 30-day episode-of-care costs following rTKA. Secondary outcomes included surgical cost, 90-day readmission rate, and emergency department visit rate. Covariates for analyses included patient demographics, surgery type, and indication for revision.

RESULTS

There were 6,515 patients who were identified, with 17.0% of rTKAs taking place in an outpatient setting. On adjusted analysis, patients in the highest quartile of 30-day postoperative costs were more likely to be those whose rTKA was performed in an inpatient setting. One-component revisions were more common in an outpatient setting (HOPD, 50.7%; ASC, 62.0%) compared to an inpatient setting (39.6%). The 90-day readmission rates were higher (P = .003) for rTKAs performed in inpatient (+9.2%) and HOPD (+8.6%) settings compared to those in an ASC.

CONCLUSIONS

The ASC may be a suitable setting for simpler revisions performed for less severe indications and is associated with lower costs and 90-day readmission and emergency department visit rates.

Emerging Strategies to Prevent Bacterial Infections on Titanium-Based Implants

Titanium and titanium alloys remain the gold standard for dental and orthopedic implants. These materials are heavily used because of their bioinert nature, robust mechanical properties, and seamless integration with bone. However, implant-associated infections (IAIs) remain one of the leading causes of implant failure. Eradicating an IAI can be difficult since bacteria can form biofilms on the medical implant, protecting the bacterial cells against systemic antibiotics and the host's immune system. If the infection is not treated promptly and aggressively, device failure is inevitable, leading to costly multi-step revision surgeries. To circumvent this dire situation, scientists and engineers continue to develop novel strategies to protect the surface of medical implants from bacteria. In this review, details on emerging strategies to prevent infection in titanium implants are reported. These strategies include anti-adhesion properties provided by polymers, superhydrophobic, superhydrophilic, and liquid-infused surface coatings, as well as strategies and coatings employed to lyse the bacteria. Additionally, commercially available technologies and those under preclinical trials are examined while discussing current and future trends.

Leveraging transfer learning for predicting total knee arthroplasty failure from post-operative radiographs

Purpose

The incidence of both primary and revision total knee arthroplasty (TKA) is expected to rise, making early recognition of TKA failure crucial to prevent extensive revision surgeries. This study aims to develop a deep learning (DL) model to predict TKA failure using radiographic images.

Methods

Two patient cohorts who underwent primary TKA were retrospectively collected: one was used for the model development and the other for the external validation. Each cohort encompassed failed and non-failed subjects, according to the need for TKA revision surgery. Moreover, for each patient, one anteroposterior and one lateral radiographic view obtained during routine TKA follow-up, were considered. A transfer learning fine-tuning approach was employed. After pre-processing, the images were analyzed using a convolutional neuronal network (CNN) that was originally developed for predicting hip prosthesis failure and was based on the Densenet169 pre-trained on Imagenet. The model was tested on 20% of the images of the first cohort and externally validated on the images of the second cohort. Metrics, such as accuracy, sensitivity, specificity and area under the receiving operating characteristic curve (AUC), were calculated for the final assessment.

Results

The trained model correctly classified 108 out of 127 images in the test set, providing a classification accuracy of 0.85, sensitivity of 0.80, specificity of 0.89 and AUC of 0.86. Moreover, the model correctly classified 1547 out of 1937 in the external validation set, providing a balanced accuracy of 0.79, sensitivity of 0.80, specificity of 0.78 and AUC of 0.86.

Conclusions

The present DL model predicts TKA failure with moderate accuracy, regardless of the cause of revision surgery. Additionally, the effectiveness of the transfer learning fine-tuning approach, leveraging a previously developed DL model for hip prosthesis failure, has been successfully demonstrated.

Level of Evidence

Level III, diagnostic study.

Short-term Comparison of Survivorship and Functional Outcomes for Metaphyseal Cones with Short and Long Stems in Revision Total Knee Arthroplasty

Printed porous titanium metaphyseal cones have become a mainstay for managing bone loss in revision total knee arthroplasty (rTKA). A short or long stem is routinely used when implanting a cone to augment fixation and offload stresses. This retrospective analysis compared the short-term survivorships and functional outcomes for use of a short or long stem with a metaphyseal cone.A total of 179 cases using metaphyseal cones and stems with median follow-up of 1.95 years (interquartile range, 1.00-2.14) were compared based on stem type. There were 55 cases with long stem(s) and 124 cases with short stem(s). Cases with both long and short stems were excluded. Demographics, Kaplan-Meier survivorships, and preoperative and 1-year postoperative patient-reported outcome measures (PROMs; 2011 Knee Society Score [KSS] objective knee score, function, and satisfaction scores; EuroQol five-dimension scale; and Short Form Survey Physical Component Summary and Mental Component Summary scores) were compared using t-tests with a significance level of α = 0.05. There were no significant differences in body mass index (mean ± standard deviation) or sex (men [%]) between the short and long stem cohorts (32.3 ± 5.3, 36.3% and 31.5 ± 5.5, 38.2%, respectively; p > 0.05). Patients who had short stems were younger (65.9 ± 8.8 vs. 69.0 ± 9.4, p = 0.0323).Revision-free survivorship for the femoral or tibial component was 100% for long stems and 98.2% for short stems at 1 and 2 years, respectively (log-rank p = 0.6330). The two revisions in the short group were for infection, thus the survivorship for aseptic loosening was 100% at 2 years for both cohorts. There were no significant differences in preoperative or postoperative PROMs.This study demonstrated that highly porous printed metaphyseal cones provided rTKA with excellent early survivorship and similar PROMs whether a short or long stem was used. Additional studies will be needed to discern longer term differences.

Assessment of the Potential Role of Preoperative Dental Clearance in Total Joint Arthroplasty Optimization: A Pilot Study

AIMS AND OBJECTIVES

Periprosthetic joint infection (PJI) is a serious complication after total joint arthroplasty (TJA) and is associated with significant morbidity, mortality, and cost. This pilot study primarily aimed to investigate if preoperative dental screenings would impact the rate of PJI following TJA when compared to historical controls. Secondarily, this study aimed to evaluate the prevalence of dental pathology in patients undergoing TJA.

METHODS

Charts from 103 consecutive patients undergoing primary or revision total hip arthroplasty (THA, rTHA) or total knee arthroplasty (TKA, rTKA) by a single surgeon at a single academic institution over a two-year period were reviewed and selected for inclusion. All patients were referred to a dentist for preoperative clearance using a standardized form. The rate of dental pathology before surgery, details of the dental intervention required, and any dental work performed within six months postoperatively were evaluated. The demographic and comorbidity composition of our patient population was also collected. Finally, rates of PJI following each type of TJA were obtained for demographic- and comorbidity-matched historical controls from similar study designs to examine the potential impact of preoperative dental intervention.

RESULTS

Of the 103 patients, 31 (30.1%) were found to have preoperative dental pathology. Twenty-eight of these 31 patients (90.3%) required dental intervention prior to surgery. Based on demographic- and comorbidity-matched historical data, we expected two (95% CI (0, 6)) PJI cases for the THA group, 0 (95% CI (0, 2)) PJI cases for the TKA group, two (95% CI (0, 5)) PJI cases for the rTHA group, and two (95% CI (0, 5)) PJI cases for the rTKA group. However, in our study, there were no PJIs after any TJA up to the latest follow-up, which was unlikely for THA, rTHA, and rTKA groups given the calculated Poisson probabilities (9.39%, 15.11%, and 11.26%, respectively). Finding 0 cases was likely for the TKA group given the calculated Poisson probability of 72.61%.

CONCLUSIONS

This pilot study demonstrated that preoperative dental screening, which aims to decrease the chance of PJI due to bacteremia, may have an impact on the rate of PJI following THA, rTKA, and rTHA but not TKA based on Poisson probabilities calculated from demographic- and comorbidity-matched historical controls that lacked preoperative dental screening. For THA, rTKA, and rTHA, the Poisson probabilities of observing 0 cases of PJI postoperatively, as was the case in our study, were unlikely, suggesting that some variable in our cohort was decreasing the PJI rate for these groups. However, in the case of TKA, the Poisson probability of observing 0 cases was likely and matched the results of our study, suggesting that no variable in our cohort was affecting the PJI rate for this group. We cannot draw direct conclusions from this retrospective observational study, but the preliminary findings prompt further investigation through an appropriately controlled, blinded, multi-centered, and powered prospective randomized controlled trial.

What Is the Correlation between Coronal Plane Alignment Measured on Pre- and Postoperative Weight-bearing Radiographs and Intraoperative Navigation When Stress Is Applied to the Knee?

This study examines the correlation between the weight-bearing (WB) long leg radiograph (LLR)-derived hip-knee-ankle angle (HKAA) and intraoperative supine computer-assisted surgery (CAS)-derived HKAA measurements at the beginning and end of total knee arthroplasty (TKA). The primary aim of the study was to determine if WB alignment could be mimicked or inferred based on intraoperative alignment findings. We conducted a prospective analysis from a cohort of 129 TKAs undergoing a CAS TKA at a single center by a single surgeon. The HKAA was recorded using the CAS navigation system immediately postregistration of navigation data and after implantation of the prosthesis. The intraoperative HKAA was recorded in both the supine "resting" position of the knee and also while the knee was manipulated in an effort to replicate the patient's WB alignment. These measurements were compared with the HKAA recorded on pre- and postoperative WB LLRs. There was a strong correlation between the preoperative WB LLR HKAA and the intraoperative preimplant CAS-derived stressed HKAA (R = 0.946). However, there was no correlation between the postoperative WB LLR HKAA and the postimplant insertion HKAA as measured intraoperatively via CAS for either a "resting" or "stressed" position of the operated knee (R = 0.165 and R = 0.041, respectively). Thus, the interpretation of intraoperative alignment data is potentially problematic. Despite technological advances in the development and utilization of computer navigation and robotics in arthroplasty to help obtain the optimal alignment, it would seem apparent from our study that this alignment does not correlate to upright stance postoperatively. Surgeons should apply caution to the strength of assumptions they place on intraoperative coronal plane alignment findings.

Predicting 30-day unplanned hospital readmission after revision total knee arthroplasty: machine learning model analysis of a national patient cohort

Revision total knee arthroplasty (TKA) is associated with a higher risk of readmission than primary TKA. Identifying individual patients predisposed to readmission can facilitate proactive optimization and increase care efficiency. This study developed machine learning (ML) models to predict unplanned readmission following revision TKA using a national-scale patient dataset. A total of 17,443 revision TKA cases (2013-2020) were acquired from the ACS NSQIP database. Four ML models (artificial neural networks, random forest, histogram-based gradient boosting, and k-nearest neighbor) were developed on relevant patient variables to predict readmission following revision TKA. The length of stay, operation time, body mass index (BMI), and laboratory test results were the strongest predictors of readmission. Histogram-based gradient boosting was the best performer in distinguishing readmission (AUC: 0.95) and estimating the readmission probability for individual patients (calibration slope: 1.13; calibration intercept: -0.00; Brier score: 0.064). All models produced higher net benefit than the default strategies of treating all or no patients, supporting the clinical utility of the models. ML demonstrated excellent performance for the prediction of readmission following revision TKA. Optimization of important predictors highlighted by our model may decrease preventable hospital readmission following surgery, thereby leading to reduced financial burden and improved patient satisfaction.

Are Femoral Stems in Primary Total Knee Arthroplasty Cost Effective in High Fracture Risk Patients? A Risk Model and Cost Analysis

Femoral stemmed total knee arthroplasty (FS TKA) may be used in patients deemed higher risk for periprosthetic fracture (PPF) to reduce PPF risk. However, the cost effectiveness of FS TKA has not been defined. Using a risk modeling analysis, we investigate the cost effectiveness of FS in primary TKA compared with the implant cost of revision to distal femoral replacement (DFR) following PPF. A model of risk categories was created representing patients at increasing fracture risk, ranging from 2.5 to 30%. The number needed to treat (NNT) was calculated for each risk category, which was multiplied by the increased cost of FS TKA and compared with the cost of DFR. The 50th percentile implant pricing data for primary TKA, FS TKA, and DFR were identified and used for the analysis. FS TKA resulted in an increased cost of $2,717.83, compared with the increased implant cost of DFR of $27,222.29. At 50% relative risk reduction with FS TKA, the NNT for risk categories of 2.5, 10, 20, and 30% were 80, 20, 10, and 6.67, respectively. At 20% risk, FS TKA times NNT equaled $27,178.30. A 10% absolute risk reduction in fracture risk obtained with FS TKA is needed to achieve cost neutrality with DFR. FS TKA is not cost effective for low fracture risk patients but may be cost effective for patients with fracture risk more than 20%. Further study is needed to better define the quantifiable risk reduction achieved in using FS TKA and identify high-risk PPF patients.

Knotless suture in revision total joint arthroplasty: a prospective randomized controlled trial

INTRODUCTION

The use of barbed sutures for wound closure in primary total joint arthroplasty (TJA) has been shown to be effective and safe. However, their effectiveness and safety in revision TJA procedures has not been thoroughly studied. This study aims to evaluate the efficacy and safety of using barbed suture closure in revision TJA setting.

METHODS

A total of 80 patients undergoing revision TJA between September 2020 and November 2022 were included in this randomized controlled trial study. Following informed consent, patients were computer-randomized to the treatment arm (barbed suture wound closure) or to the control arm (conventional wound closure). Closure duration, closure rate, number of sutures used and wound related outcomes including complication rates and Patient and Observer Scar Assessment Scale (POSAS) score were compared between groups.

RESULTS

The use of barbed sutures decreased closure time by 6 min (30.1 vs. 36.1 min, P = 0.008) with a higher wound closure rate (6.5 vs. 5.5 mm/minute, P = 0.013). Additionally, the number of sutures used for wound closure in the barbed group was significantly lower than in the control group (6.2 vs. 10.1, respectively, P < 0.001). There were no significant differences in the rate of postoperative wound complications (P = 0.556) or patient and observer POSAS scores (P = 0.211, P = 297, respectively) between the two groups at 3-month follow-up.

CONCLUSION

Closure of revision TJA surgical wound utilizing barbed sutures reduced closure time and the number of needles handled by operative staff, with no significant increase in intra- or post-operative complications rate when compared to traditional closure technique.

LEVEL OF EVIDENCE

I.

Adipose-derived regenerative therapies for the treatment of knee osteoarthritis

Knee osteoarthritis is a degenerative condition with a significant disease burden and no disease-modifying therapy. Definitive treatment ultimately requires joint replacement. Therapies capable of regenerating cartilage could significantly reduce financial and clinical costs. The regenerative potential of mesenchymal stromal cells (MSCs) has been extensively studied in the context of knee osteoarthritis. This has yielded promising results in human studies, and is likely a product of immunomodulatory and chondroprotective biomolecules produced by MSCs in response to inflammation. Adipose-derived MSCs (ASCs) are becoming increasingly popular owing to their relative ease of isolation and high proliferative capacity. Stromal vascular fraction (SVF) and micro-fragmented adipose tissue (MFAT) are produced by the enzymatic and mechanical disruption of adipose tissue, respectively. This avoids expansion of isolated ASCs ex vivo and their composition of heterogeneous cell populations, including immune cells, may potentiate the reparative function of ASCs. In this editorial, we comment on a multicenter randomized trial regarding the efficacy of MFAT in treating knee osteoarthritis. We discuss the study's findings in the context of emerging evidence regarding adipose-derived regenerative therapies. An underlying mechanism of action of ASCs is proposed while drawing important distinctions between the properties of isolated ASCs, SVF, and MFAT.

Mental Health Effects on the Minimal Clinically Important Difference in Total Joint Arthroplasty

INTRODUCTION

The effect of mental health on patient-reported outcome measures is not fully understood in total joint arthroplasty (TJA). Thus, we investigated the relationship between mental health diagnoses (MHDs) and the Minimal Clinically Important Difference for Improvement (MCID-I) and Worsening (MCID-W) in primary TJA and revision TJA (rTJA).

METHODS

Retrospective data were collected using relevant Current Procedural Terminology and MHDs International Classification of Diseases, 10th Revision, codes with completed Hip Disability and Osteoarthritis Outcome Score-Physical Function Short Form, Knee Injury and Osteoarthritis Outcome Score-Physical Function Short Form, Patient-reported Outcomes Measurement Information System (PROMIS)-Physical Function Short Form 10a, PROMIS Global-Mental, or PROMIS Global-Physical questionnaires. Logistic regressions and statistical analyses were used to determine the effect of a MHD on MCID-I/MCID-W rates.

RESULTS

Data included 4,562 patients (4,190 primary TJAs/372 rTJAs). In primary total hip arthroplasty (pTHA), MHD-affected outcomes for Hip Disability and Osteoarthritis Outcome Score-Physical Function Short Form (MCID-I: 81% versus 86%, P = 0.007; MCID-W: 6.0% versus 3.2%, P = 0.008), Physical Function Short Form 10a (MCID-I: 68% versus 77%, P < 0.001), PROMIS Global-Mental (MCID-I: 38% versus 44%, P = 0.009), and PROMIS Global-Physical (MCID-I: 61% versus 73%, P < 0.001; MCID-W: 14% versus 7.9%, P < 0.001) versus pTHA patients without MHD. A MHD led to lower rates of MCID-I for PROMIS Global-Physical (MCID-I: 56% versus 63%, P = 0.003) in primary total knee arthroplasty patients. No effects from a MHD were observed in rTJA patients.

DISCUSSION

The presence of a MHD had a prominent negative influence on pTHA patients. Patients who underwent rTJA had lower MCID-I rates, higher MCID-W rates, and lower patient-reported outcome measure scores despite less influence from a MHD.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Use of Biomaterials in 3D Printing as a Solution to Microbial Infections in Arthroplasty and Osseous Reconstruction

The incidence of microbial infections in orthopedic prosthetic surgeries is a perennial problem that increases morbidity and mortality, representing one of the major complications of such medical interventions. The emergence of novel technologies, especially 3D printing, represents a promising avenue of development for reducing the risk of such eventualities. There are already a host of biomaterials, suitable for 3D printing, that are being tested for antimicrobial properties when they are coated with bioactive compounds, such as antibiotics, or combined with hydrogels with antimicrobial and antioxidant properties, such as chitosan and metal nanoparticles, among others. The materials discussed in the context of this paper comprise beta-tricalcium phosphate (β-TCP), biphasic calcium phosphate (BCP), hydroxyapatite, lithium disilicate glass, polyetheretherketone (PEEK), poly(propylene fumarate) (PPF), poly(trimethylene carbonate) (PTMC), and zirconia. While the recent research results are promising, further development is required to address the increasing antibiotic resistance exhibited by several common pathogens, the potential for fungal infections, and the potential toxicity of some metal nanoparticles. Other solutions, like the incorporation of phytochemicals, should also be explored. Incorporating artificial intelligence (AI) in the development of certain orthopedic implants and the potential use of AI against bacterial infections might represent viable solutions to these problems. Finally, there are some legal considerations associated with the use of biomaterials and the widespread use of 3D printing, which must be taken into account.

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.

Patient Adherence Following Knee Surgery: Evidence-Based Practices to Equip Patients for Success

Patient adherence with postoperative wound care, activity restrictions, rehabilitation, medication, and follow-up protocols is paramount to achieving optimal outcomes following knee surgery. However, the ability to adhere to prescribed postoperative protocols is dependent on multiple factors both in and out of the patient's control. The goals of this review article are (1) to outline key factors contributing to patient nonadherence with treatment protocols following knee surgery and (2) to synthesize current management strategies and tools for optimizing patient adherence in order to facilitate efficient and effective implementation by orthopaedic health care teams. Patient adherence is commonly impacted by both modifiable and nonmodifiable factors, including health literacy, social determinants of health, patient fear/stigma associated with nonadherence, surgical indication (elective vs. traumatic), and distrust of physicians or the health care system. In addition, health care team factors, such as poor communication strategies or failure to follow internal protocols, and health system factors, such as prior authorization delays, staffing shortages, or complex record management systems, impact patient's ability to be adherent. Because the majority of factors found to impact patient adherence are nonmodifiable, it is paramount that health care teams adjust to better equip patients for success. For health care teams to successfully optimize patient adherence, focus should be paid to education strategies, individualized protocols that consider patient enablers and barriers to adherence, and consistent communication methodologies for both team and patient-facing communication.

Comparing machine learning algorithms for non-invasive detection and classification of failure in piezoresistive bone cement via electrical impedance tomography

At an estimated cost of $8 billion annually in the United States, revision surgeries to total joint replacements represent a substantial financial burden to the health care system and a tremendous mental and physical burden on patients and their caretakers. Fixation failures, such as implant loosening, wear, and mechanical instability of the poly(methyl methacrylate) (PMMA) cement, which bonds the implant to the bone, are the main causes of long-term implant failure. Early and accurate diagnosis of cement failure is critical for developing novel therapeutic strategies and reducing the high risk of a misjudged revision. Unfortunately, prevailing imaging modalities, notably plain radiographs, struggle to detect the precursors of implant failure and are often interpreted incorrectly. Our prior work has shown that the modification of PMMA bone cement with low concentrations of conductive fillers makes it piezoresistive and therefore self-sensing. When combined with a conductivity imaging modality such as electrical impedance tomography (EIT), it is possible to monitor load transfer across the PMMA using cost-effective, physiologically benign, non-contact, and real-time electrical measurements. Despite the ability of EIT for monitoring load transfer across self-sensing PMMA bone cement, it is unable to accurately characterize failure mechanisms. Overcoming this challenge is critical to the success of this technology in practice. Therefore, we herein expand upon our previous results by integrating machine learning techniques with EIT for cement condition characterization with the goal of establishing the feasibility of even off-the-shelf machine learning algorithms to address this important problem. We survey a wide variety of different machine learning algorithms for application to this problem, including neural networks on voltage readings of an EIT phantom for tracking the spatial position of a sample, specifying defect orientation within a sample, and classifying defect types, including cracks and delaminations. In addition, we explore the utilization of principal component analysis (PCA) for pre-treating impedance signals in each of these problems. Within the tested algorithms, our results show clear advantages of neural networks, support vector machines, and K-nearest neighbor algorithms for interpreting EIT signals. We also show that PCA is an effective addition to machine learning. These preliminary results demonstrate that the combination of smart materials, EIT, and machine learning may be a powerful instrumentation tool for diagnosing the origin and evolution of mechanical failure in joint replacements.

Orthopedic consequences of modern gladiators: a systematic review of lower extremity musculoskeletal issues in retired NFL players

OBJECTIVES

The stressors that National Football League (NFL) athletes face are well-described and documented with regard to multisystem afflictions and injury prevalence. However, the majority of literature discusses the short-term effects rather than long-term outcomes of playing professional football. The purpose of this study was to characterize the long-term musculoskeletal issues in the retired NFL population.

METHODS

Publications from CENTRAL, Scopus, Medline, PubMed, Embase, and Google Scholar were searched from database inception to February 2021. A total of 9 cohort studies evaluating lower extremity arthritis in retired NFL athletes were included for review. Two reviewers extracted data from the individual studies, including demographic information (age, body mass index, length of career, position), injury descriptions (location of injury, number of injuries, diagnoses), and procedure (total knee and or hip arthroplasty) frequency.

RESULTS

Arthritis in retired NFL players was more than twice as prevalent than the general United States male population (95% CI: 2.1-2.3). Ankle osteoarthritis was directly correlated with the number of foot and ankle injuries. Players <50 years of age had a 16.1 and 13.8 times higher risk of undergoing TKA and THA, respectively, when compared to the general population. In older age groups, this trend held with retired NFL players being at least 4.3 and 4.6 times more likely than members of the general population to undergo TKA and THA, respectively.

CONCLUSION

This review demonstrates that the effects of NFL-related lower extremity injuries extend beyond the players' careers and present a higher risk for early-onset osteoarthritis and overall frequency of undergoing total knee and hip arthroplasty.

Early results of a novel modular knee arthrodesis implant after uncontrolled periprosthetic knee joint infection

AIM

The aim of this study is to evaluate the functional outcomes and complications after non-fusion knee arthrodesis with a modular segmental intramedullary implant used for infected total knee arthroplasty revisions.

METHODS

A retrospective review of the patients who had been surgically treated with a modular intramedullary arthrodesis implant for recurrent infection after revision TKA between January 2016 and February 2020 were included. The indications for arthrodesis were failed infected TKA with massive bone loss, deficient extensor mechanism and poor soft tissue coverage that precluded joint reconstruction with revision TKA implants. Clinical outcomes were assesed with visual analogue scale for pain (pVAS), Oxford knee score (OKS) and 12-item short form survey (SF-12). Full-length radiographs were used to verify limb length discrepancies (LLD).

RESULTS

Fourteen patients (4 male and 10 female) patients with a mean age of 69.3 (range, 59 to 81) years at time of surgery were available for final follow-up at a mean of 28.8 months (range, 24-35 months). All clinical outcome scores improved at the final follow-up (pVAS, 8.5 to 2.6, p = .01; OKS, 12.6 to 33.8, p = .02; SF-12 physical, 22.9 to 32.1, p = .01 and SF-12 mental, 27.7 to 40.2, p = .01). The mean LLD was 1.0 cm (range, + 15 - 2.3 cm). Re-infection was detected in three patients (21.4%). Two patients were managed with suppressive antibiotic treatment and a third patient required repeat 2-stage revision procedure. In one patient, a periprosthetic femur fracture was observed and treated with plate osteosynthesis.

CONCLUSION

Uncontrolled infection after total knee arthroplasty can be effectively treated with arthrodesis using a modular intramedullary nail and satisfactory functional results can be obtained.

LEVEL OF EVIDENCE

Level 4, Retrospective cohort study.

A call to "own the bone": osteoporosis is a predictor for adverse two-year outcomes following total hip and knee arthroplasty

PURPOSE

While bone health is instrumental in orthopedic surgery, few studies have described the long-term outcomes of osteoporosis (OP) in patients undergoing total hip (THA) or knee (TKA) arthroplasties.

METHODS

Using the New York State statewide planning and research cooperative system database, all patients who underwent primary TKA or THA for osteoarthritis from 2009 to 2011 with minimum 2-year follow-up were identified. They were divided based on their OP status (OP and non-OP) and 1:1 propensity score matched for age, sex, race, and Charlson/Deyo index. Cohorts were compared for demographics, hospital-related parameters, and 2-year postoperative complications and reoperations. Multivariate binary logistic regression was utilized to identify significant independent associations with 2-year medical and surgical complications and revisions.

RESULTS

A total of 11,288 TKA and 8248 THA patients were identified. OP and non-OP TKA patients incurred comparable overall hospital charges for their surgical visit and hospital length of stay (LOS) (both, p ≥ 0.125). Though OP and non-OP THA patients incurred similar mean hospital charges for their surgical visit, they experienced longer hospital LOS (4.3 vs. 4.1 days, p = 0.035). For both TKA and THA, OP patients had higher rates of overall and individual medical and surgical complications (all, p < 0.05). OP was independently associated with the 2-year occurrence of any overall, surgical, and medical complications, and any revision in TKA and THA patients (all, OR ≥ 1.42, p < 0.001).

CONCLUSION

Our study found OP was associated with a greater risk of 2-year adverse outcomes following TKA or THA, including medical, surgical, and overall complications as well as revision operations compared to non-OP patients.

Artificial Intelligence for Automated Implant Identification in Knee Arthroplasty: A Multicenter External Validation Study Exceeding 3.5 Million Plain Radiographs

BACKGROUND

Surgical management of complications following knee arthroplasty demands accurate and timely identification of implant manufacturer and model. Automated image processing using deep machine learning has been previously developed and internally validated; however, external validation is essential prior to scaling clinical implementation for generalizability.

METHODS

We trained, validated, and externally tested a deep learning system to classify knee arthroplasty systems as one of the 9 models from 4 manufacturers derived from 4,724 original, retrospectively collected anteroposterior plain knee radiographs across 3 academic referral centers. From these radiographs, 3,568 were used for training, 412 for validation, and 744 for external testing. Augmentation was applied to the training set (n = 3,568,000) to increase model robustness. Performance was determined by the area under the receiver operating characteristic curve, sensitivity, specificity, and accuracy. Implant identification processing speed was calculated. The training and testing sets were drawn from statistically different populations of implants (P < .001).

RESULTS

After 1,000 training epochs by the deep learning system, the system discriminated 9 implant models with a mean area under the receiver operating characteristic curve of 0.989, accuracy of 97.4%, sensitivity of 89.2%, and specificity of 99.0% in the external testing dataset of 744 anteroposterior radiographs. The software classified implants at a mean speed of 0.02 seconds per image.

CONCLUSION

An artificial intelligence-based software for identifying knee arthroplasty implants demonstrated excellent internal and external validation. Although continued surveillance is necessary with implant library expansion, this software represents a responsible and meaningful clinical application of artificial intelligence with immediate potential to globally scale and assist in preoperative planning prior to revision knee arthroplasty.

Outcomes of Total Knee Arthroplasty Revisions in Obese and Morbidly Obese Patient Populations

BACKGROUND

The obese population is at higher risk for complications following primary total knee arthroplasty (TKA), but little data is available regarding revision outcomes. This study aimed to investigate the role of body mass index (BMI) in the cause for revision TKA and whether BMI classification is predictive of outcomes.

METHODS

A multi-institutional database was generated, including revision TKAs from 2012 to 2019. Data collection included demographics, comorbidities, surgery types (primary revision, repeat revision), reasons for revision, lengths of hospital stay, and surgical times. Patients were compared using 3 BMI categories: nonobese (18.5 to 29.9), obese (30 to 39.9), and morbidly obese (≥40). Categorical and continuous variables were analyzed using chi-square and 1-way analysis of variance tests, respectively. Regression analyses were used to compare reasons for revision among weight classes.

RESULTS

Obese and morbidly obese patients showed significant risk for repeat revision surgery in comparison to normal weight patients. Obese patients were at higher risk for primary revision due to stiffness/fibrosis and repeat revision due to malposition. In comparison to the obese population, morbidly obese patients were more likely to require primary revision for dislocation and implant loosening.

CONCLUSION

Significant differences in primary and repeat revision etiologies exist among weight classes. Furthermore, obese and morbidly obese patients have a greater risk of requiring repeat revision surgery. These patients should be informed of their risk for multiple operations, and surgeons should be aware of the differences in revision etiologies when anticipating complications following primary TKA.

Induction Heating Triggers Antibiotic Release and Synergistic Bacterial Killing on Polymer-Coated Titanium Surfaces

Infection is a major complication associated with orthopedic implants. It often involves the development of biofilms on metal substrates, which act as barriers to the host's immune system and systemic antibiotic treatment. The current standard of treatment is revision surgery, often involving the delivery of antibiotics through incorporation into bone cements. However, these materials exhibit sub-optimal antibiotic release kinetics and revision surgeries have drawbacks of high cost and recovery time. Herein, a new approach is presented using induction heating of a metal substrate, combined with an antibiotic-loaded poly(ester amide) coating undergoing a glass transition just above physiological temperature to enable thermally triggered antibiotic release. At normal physiological temperature, the coating provides a rifampicin depot for >100 days, while heating of the coating accelerates drug release, with >20% release over a 1-h induction heating cycle. Induction heating or antibiotic-loaded coating alone each reduce Staphylococcus aureus (S. aureus) viability and biofilm formation on Ti, but the combination causes synergistic killing of S. aureus as measured by crystal violet staining, determination of bacterial viability (>99.9% reduction), and fluorescence microscopy of bacteria on surfaces. Overall, these materials provide a promising platform enabling externally triggered antibiotic release to prevent and/or treat bacterial colonization of implants.

Clinical Outcomes and Infection Rates Following Revision Total Knee Arthroplasty: Aseptic Failure versus Septic Failure

Background

It is controversial whether revision total knee arthroplasty (TKA) due to septic failure shows inferior clinical outcomes compared with TKA due to aseptic failure. Moreover, few studies have compared the infection rates after revision TKA between aseptic and septic failure. We aimed to compare the clinical outcomes and infection rates after aseptic and septic revision TKA.

Methods

Between April 2006 and May 2019, 68 and 26 patients underwent revision TKA due to aseptic failure (aseptic group) and septic failure (septic group), respectively. The postoperative range of motion (ROM), Western Ontario and McMaster Universities Osteoarthritis index, Knee Society Knee Score (KSKS), Knee Society Function Score (KSFS), and infection rates were compared between the two groups.

Results

The mean follow-up durations in the aseptic and septic groups were 44.4 and 54.8 months, respectively. The septic group showed inferior postoperative ROM (124.1° and 109.4°, p = 0.004), KSKS (88.9 and 78.8, p = 0.001), and KSFS (72.8 and 59.0, p = 0.001). Three patients of aseptic group had infection. Three patients of septic group had recurred infection (same pathogen with the first infection) and 1 patient had a new infection (different pathogen). The septic group showed slightly higher but not significantly different infection rates (4.4% and 15.4%, p = 0.089).

Conclusions

Revision TKA with septic failure showed inferior postoperative clinical outcomes compared with aseptic revision surgery. A slightly higher infection rate was observed in the septic group but it was not significantly different.

Using acoustic feedback and analyses for removal of bone cement during revision knee replacement surgeries

PURPOSE

The purpose of this study was to analyze the scraping sounds generated during revision knee replacement surgeries to discriminate between the inner cortical bone and the cement, with the goal of minimizing bone removal and increasing the structural integrity of the revision.

METHODS

We prepared seven porcine femurs by partially filling them with bone cement, and recorded scraping sounds produced by a surgical scraping tool. We used a hierarchical machine learning approach to first detect a contact and then classify it as either bone or cement. This approach was based on a Support Vector Machine learning algorithm that was fed with temporal and spectral features of the sounds. A Leave-One-Bone-Out validation method was used to assess the performance of the proposed method.

RESULTS

The average recall for the noncontact, bone, and cement classes was 98%, 75%, and 72%, respectively. The corresponding precision for the respective classes was 99%, 67%, and 61%.

CONCLUSION

The scraping sound that is generated during revision replacement surgeries carries significant information about the material that is being scraped. Such information can be extracted using a supervised machine learning algorithm. The scraping sound produced during revision replacement procedures can potentially be used to enhance cement removal during knee revision surgery. Future work will assess whether such monitoring can increase the structural integrity of the revision.

A Comprehensive Research on the Prevalence and Evolution Trend of Orthopedic Surgeries in Romania

Accurate knowledge of the prevalence and trends of orthopedic surgeries can facilitate the design of medical plans for effective treatments. The National Endoprosthetic Registry (NER) in Romania provides statistics on endoprosthetic activity (hip, knee), cases of fractures and bone tumors as a result of the legal obligations to report interventions performed by all orthopedic traumatology hospitals/wards in the country. The aim of this study is to describe the annual volumes of orthopedic surgeries between 2001 and 2022 in Romania and analyze the current and future evolution trends of the studied surgeries, gender differences and regional differences based on a complete survey carried out at a national level. For the period 2001-2022, we extracted from the NER the annual volumes of orthopedic interventions performed. With these data, we studied the prevalence and estimated, with the support of an original calculation methodology, the variation trends of orthopedic surgeries in two situations: over the entire 21-year period, respectively, and over the period 2001-2020, which does not include the pandemic period. For hip replacement surgery and knee replacement surgery, we showed the prevalence by subcategory of interventions, gender distribution, regional prevalence and regional density calculated by the annual averages of the total number of cases reported per 100,000 people in the 40 counties of the country and the capital, Bucharest. We also determined the variations in hip and knee arthroplasty revision burdens, calculated as a percentage between the number of revisions and the number of primary interventions in the same period. We determined the regional densities of revision burdens. The total number of orthopedic surgeries in the period 2001-2022 was 1,557,247, of which 189,881 were hip replacement surgeries; 51,035 were knee replacement surgeries; 11,085 were revision hip arthroplasty; 1497 were revision knee arthroplasty; 541,440 were operated fractures; and 16,418 were operated bone tumors. The growth rates of surgical interventions are hip replacement surgery, +8.19%; knee replacement surgery, +19.55%; revision hip arthroplasty, +9.43%; and revision knee arthroplasty, +28.57%. With these data, we have estimated a doubling of the volume of primary and revision interventions of the hip until 2034 and the knee until 2027, respectively. Operated bone tumors register an annual decrease of -4.52% thanks to modern treatments. There are clear gender differences; for primary hip interventions, the proportion of women is 58.82%, and for knee interventions, the proportion of women is 76.42%. This is the first research that, with the support of exhaustive data from the NER, analyzes for the period 2001-2022 the annual number of orthopedic surgeries in Romania. It allows knowledge of the large, anticipated increases in orthopedic surgery and provides a quantitative basis for future policy decisions related to the need for medical personnel and material resources.

Cementless Compared to Cemented Total Knee Arthroplasty is Associated With More Revisions Within 1 Year of Index Surgery

Background

Cementless total knee arthroplasties (TKAs) have gained renewed interest due to improved implant designs and lower rates of revision than its cemented counterparts. The purpose of this study was to compare revision rates between cemented vs cementless TKAs within 1 year of primary arthroplasty.

Methods

This was a retrospective review from the PearlDiver Patient Record Database. International Classification of Diseases and Current Procedural Terminology codes were used to identify patients who had undergone cemented and cementless TKAs and subsequent surgical revisions. An unadjusted univariate analysis of patient demographics, Charlson Comorbidity Index score, and surgical revisions at 90 days and 1 year after TKA was performed using chi-squared testing. Multivariate logistic regression analyses were subsequently performed for 1-year surgical complications requiring revision.

Results

Of 324,508 patients, 312,988 (96.45%) underwent cemented TKAs, and 11,520 (3.55%) underwent cementless TKAs. Patients undergoing cementless TKA tended to be younger than patients undergoing cemented TKA (63.67 ± 9.15 cementless vs 66.22 ± 8.85 cemented, P < .001). Univariate chi-squared testing showed that cementless patients were more likely to require 1-component femoral or tibial revision at 90 days and 1 year, irrigation and debridement at 90 days and 1 year, and arthroscopy with lysis of adhesions at 1 year only. Similar findings were observed for these 3 revision procedures at 1 year after correcting for age, gender, and Charlson Comorbidity Index score using multivariate logistic regression analysis as cementless TKA patients had higher odds ratios for each of the revisions.

Conclusions

Small but significant differences were found in surgical revisions among cementless TKAs when compared to cemented TKAs within 1 year of the index procedure.

Comparison of Clinical and Functional Outcomes in One versus Two Component Revision for Total Knee Arthroplasty

BACKGROUND

Revisions of total knee arthroplasties (TKAs) may require revision of one or both tibial and femoral components. Our purpose was to examine the clinical and functional outcomes in 1- versus 2-component TKA revisions.

METHODS

We identified 92 1-component (tibial or femoral) revisions at a single center. Our inclusion criteria were isolated revision of the tibial or femoral components with a minimum 2-year follow-up. The included cases were matched 1:2 with a control group of 2-component revisions (tibial and femoral) by age, body mass index, American Society of Anesthesiologists score, and indication for revision. We collected demographics, complications, operative times, any subsequent rerevisions, and functional outcome scores.

RESULTS

The median follow-up time for the 1- and 2-component revision groups were 10 years (range, 3 to 17) and 8 years (range, 2 to 18), respectively. The most common complication after rerevision in both groups was stiffness at 9 of 92 (9.8%) and 9 of 170 (5.3%) in the 1- and 2-component groups, respectively (P = .20). The overall complication prevalence in the 1- and 2- component revision groups was similar 20 of 92 (22%) and 35 of 170 (21%), respectively (P = .87). Subsequent rerevisions for any indication were encountered in 12 of 92 (13.0%) of the 1-component and 18 of 170 (11%) in the 2-component groups (P = .69). There was no statistical difference in survivorship or functional outcomes scores between the groups.

CONCLUSION

Our results showed that isolated revision of a single TKA component is an acceptable option, with comparable functional outcomes, complications, and survivorships when compared with both-component revision. As such, a 1-component revision should be considered where appropriate.

Multiply revised TKAs have worse outcomes compared to index revision TKAs

Aims

Revision total knee arthroplasty (rTKA) is a technically challenging and costly procedure. It is well-documented that primary TKA (pTKA) have better survivorship than rTKA; however, we were unable to identify any studies explicitly investigating previous rTKA as a risk factor for failure following rTKA. The purpose of this study is to compare the outcomes following rTKA between patients undergoing index rTKA and those who had been previously revised.

Methods

This retrospective, observational study reviewed patients who underwent unilateral, aseptic rTKA at an academic orthopaedic speciality hospital between June 2011 and April 2020 with > one-year of follow-up. Patients were dichotomized based on whether this was their first revision procedure or not. Patient demographics, surgical factors, postoperative outcomes, and re-revision rates were compared between the groups.

Results

A total of 663 cases were identified (486 index rTKAs and 177 multiply revised TKAs). There were no differences in demographics, rTKA type, or indication for revision. Multiply revised patients had significantly longer rTKA operative times (p < 0.001), and were more likely to be discharged to an acute rehabilitation centre (6.2% vs 4.5%) or skilled nursing facility (29.9% vs 17.5%; p = 0.003). Patients who had been multiply revised were also significantly more likely to have subsequent reoperation (18.1% vs 9.5%; p = 0.004) and re-revision (27.1% vs 18.1%; p = 0.013). The number of previous revisions did not correlate with the number of subsequent reoperations (r = 0.038; p = 0.670) or re-revisions (r = -0.102; p = 0.251).

Conclusion

Multiply revised TKA had worse outcomes, with higher rates of facility discharge, longer operative times, and greater reoperation and re-revision rates compared to index rTKA.

The Cost of Stiffness After Total Knee Arthroplasty

BACKGROUND

Stiffness after primary total knee arthroplasty (TKA) is debilitating and poorly understood. A heterogenous approach to the treatment is often utilized, including both nonoperative and operative treatment modalities. The purpose of this study was to examine the prevalence of treatments used between stiff and non-stiff TKA groups and their financial impact.

METHODS

An observational cohort study was conducted using a large database. A total of 12,942 patients who underwent unilateral primary TKA from January 1, 2017, to December 31, 2017, were included. Stiffness after TKA was defined as manipulation under anesthesia and a diagnosis code of stiffness or ankylosis, and subsequent diagnosis and procedure codes were used to identify the prevalence and financial impact of multiple common treatment options.

RESULTS

The prevalence of stiffness after TKA was 6.1%. Stiff patients were more likely to undergo physical therapy, medication, bracing, alternative treatment, clinic visits, and reoperation. Revision surgery was the most common reoperation in the stiff TKA group (7.6%). The incidence of both arthroscopy and revision surgery were higher in the stiff TKA population. Dual component revisions were costlier for patients who had stiff TKAs ($65,771 versus $48,287; P < .05). On average, patients who had stiffness after TKA endured costs from 1.5 to 7.5 times higher than the cost of their non-stiff counterparts during the 2 years following index TKA.

CONCLUSION

Patients who have stiffness after primary TKA face significantly higher treatment costs for both operative and nonoperative treatments than patients who do not have stiffness.

Visualizing the randomized sham-controlled trial in orthopedic research: proposed steps to conducting a total knee arthroplasty randomized controlled trial

Performed more than 600,000 times annually in the USA alone, total knee arthroplasty is the one of the most common and costly elective operations in the world. A primary total knee arthroplasty is generally an elective procedure, for which total index hospitalization costs are estimated around $30,000 USD. Roughly four in five patients declare they are satisfied postoperatively, justifying the procedure's frequency and high costs. It is sobering to realize, however, that the evidence base in favor of this procedure remains circumstantial. We as a profession lack randomized trials showing a subjective improvement over placebo intervention. We argue for the necessity of sham-controlled surgical trials in this setting and provide a surgical atlas showing how a sham operation may be performed.

Validation and Generalizability of Machine Learning Models for the Prediction of Discharge Disposition Following Revision Total Knee Arthroplasty

BACKGROUND

Postoperative discharge to facilities account for over 33% of the $ 2.7 billion revision total knee arthroplasty (TKA)-associated annual expenditures and are associated with increased complications when compared to home discharges. Prior studies predicting discharge disposition using advanced machine learning (ML) have been limited due to a lack of generalizability and validation. This study aimed to establish ML model generalizability by externally validating its prediction for nonhome discharge following revision TKA using national and institutional databases.

METHODS

The national and institutional cohorts comprised 52,533 and 1,628 patients, respectively, with 20.6 and 19.4% nonhome discharge rates. Five ML models were trained and internally validated (five-fold cross-validation) on a large national dataset. Subsequently, external validation was performed on our institutional dataset. Model performance was assessed using discrimination, calibration, and clinical utility. Global predictor importance plots and local surrogate models were used for interpretation.

RESULTS

The strongest predictors of nonhome discharge were patient age, body mass index, and surgical indication. The area under the receiver operating characteristic curve increased from internal to external validation and ranged between 0.77 and 0.79. Artificial neural network was the best predictive model for identifying patients at risk for nonhome discharge (area under the receiver operating characteristic curve = 0.78), and also the most accurate (calibration slope = 0.93, intercept = 0.02, and Brier score = 0.12).

CONCLUSION

All five ML models demonstrated good-to-excellent discrimination, calibration, and clinical utility on external validation, with artificial neural network being the best model for predicting discharge disposition following revision TKA. Our findings establish the generalizability of ML models developed using data from a national database. The integration of these predictive models into clinical workflow may assist in optimizing discharge planning, bed management, and cost containment associated with revision TKA.

Impact of revision TKA indications on resource utilization

BACKGROUND

Indications for surgery may impact resource utilization in aseptic revision total knee arthroplasty (rTKA), and understanding these relationships would facilitate risk-stratification preoperatively. The purpose of this study was to investigate the impact of rTKA indications on readmission, reoperation, length of stay (LOS), and cost.

METHODS

We reviewed all 962 patients who underwent aseptic rTKA at an academic orthopedic specialty hospital between June 2011-April 2020 with at least 90 days of follow-up. Patients were categorized based on their indication for aseptic rTKA as listed in the operative report. Demographics, surgical factors, LOS, readmission, reoperation and cost were compared between cohorts.

RESULTS

There were significant differences in operative time among cohorts (p < 0.001), highest among the periprosthetic fracture group (164.2 ± 59.8 min). Reoperation rate was greatest in the extensor mechanism disruption cohort (50.0 %, p = 0.009). Total cost differed significantly among groups (p < 0.001), which was highest among the implant failure cohort (134.6 % of mean) and lowest for component malpositioning cohort (90.2 % of mean). Similarly, there were significant differences in direct cost (p < 0.001) which was highest in the periprosthetic fracture cohort (138.5 % of mean), and lowest in the implant failure cohort (90.5 % of mean). There were no differences in discharge disposition, or number of re-revisions among all groups.

CONCLUSIONS

Operative time, components revised, LOS, readmissions, reoperation rate, total cost and direct cost following aseptic rTKA varied significantly between different revision indications. These differences should be noted for preoperative planning, resource allocation, scheduling, and risk-stratification.

LEVEL OF EVIDENCE

III, retrospective observational analysis.

Cruciate retaining total knee arthroplasty has a better 10 year survival than posterior stabilized total knee arthroplasty: a systematic review and meta-analysis

PURPOSE

There has been a long standing debate regarding superiority of cruciate retaining total knee arthroplasty over posterior stabilized total knee arthroplasty regarding the short-term outcomes as well as long-term survivorship. The proponents of both the techniques have published vast evidence in favor of their respective surgical method and early outcome in meta-analyses does not seem to be significantly different. The decision to select either design should depend on their long-term survivorship but the literature comparing their long-term survival is sparse.This meta-analysis was conducted in order to answer the following questions: (1) Does cruciate retaining total knee arthroplasty has a better long-term survival beyond 10 years.compared to posterior stabilized total knee arthroplasty? (2) Does cruciate retaining knee arthroplasty has higher complication rates compared to posterior stabilized total knee arthroplasty?

METHODS

The present systematic review and meta-analysis study was carried out following PRISMA guidelines. The following databases: Embase, Web of Science, PubMed, Scopus, the Cochrane Library, Google Scholar, and CINAHL were used to search potentially interesting articles published from database inception until January 2022. Inclusion criteria for articles were: (1) retrospective comparative studies; (2) patients who had undergone a total knee arthroplasty; (3) publications evaluating the long-term survival of cruciate-retaining (CR) versus posterior stabilizing (PS) at a minimum 10 years' follow-up; (4) publications evaluating complications of cruciate-retaining (CR) versus posterior stabilizing (PS) at a minimum 10 years' follow-up; and (5) publications reporting sufficient data regarding the outcomes. We used a fixed-effects design in the case of I² < 50% and P > 0.05; if not, we adopted a random-effects design [4]. We also performed subgroups and sensitivity analysis in order to assess the possible source of heterogeneity.

RESULTS

Database searching identified 597 studies to be screened, of which 291 abstracts were revealed as potentially eligible and finally 7 articles were included. The forest plot showed that CR had significantly better survival than PS (OR = 2.17; 95% CI: 1.69-2.80) after 10 years. However, complication rate was not significantly different between CR and PS groups (OR = 0.86; 95% CI: 0.52-1.44; P = 0.57). Subgroup analysis showed that only the period of publication constituted a source of heterogeneity in survivorship outcome. Sensitivity analysis revealed that outcomes did not differ markedly, which indicates that the meta-analysis had strong reliability.

CONCLUSION

The results of this meta-analysis showed that cruciate retaining prosthesis may be preferred over the posterior stabilized design in view of longer survivorship it offers However, further randomized controlled trials are recommended to confirm this finding.

Bone Marrow-Derived Mesenchymal Stem Cell Implants for the Treatment of Focal Chondral Defects of the Knee in Animal Models: A Systematic Review and Meta-Analysis

Osteoarthritis remains an unfortunate long-term consequence of focal cartilage defects of the knee. Associated with functional loss and pain, it has necessitated the exploration of new therapies to regenerate cartilage before significant deterioration and subsequent joint replacement take place. Recent studies have investigated a multitude of mesenchymal stem cell (MSC) sources and polymer scaffold compositions. It is uncertain how different combinations affect the extent of integration of native and implant cartilage and the quality of new cartilage formed. Implants seeded with bone marrow-derived MSCs (BMSCs) have demonstrated promising results in restoring these defects, largely through in vitro and animal studies. A PRISMA systematic review and meta-analysis was conducted using five databases (PubMed, MEDLINE, EMBASE, Web of Science, and CINAHL) to identify studies using BMSC-seeded implants in animal models of focal cartilage defects of the knee. Quantitative results from the histological assessment of integration quality were extracted. Repair cartilage morphology and staining characteristics were also recorded. Meta-analysis demonstrated that high-quality integration was achieved, exceeding that of cell-free comparators and control groups. This was associated with repair tissue morphology and staining properties which resembled those of native cartilage. Subgroup analysis showed better integration outcomes for studies using poly-glycolic acid-based scaffolds. In conclusion, BMSC-seeded implants represent promising strategies for the advancement of focal cartilage defect repair. While a greater number of studies treating human patients is necessary to realize the full clinical potential of BMSC therapy, high-quality integration scores suggest that these implants could generate repair cartilage of substantial longevity.

Does stem profile have an impact on the failure patterns in revision total knee arthroplasty?

INTRODUCTION

Revision total knee arthroplasty (RTKA) has been increasing continuously. The results of RTKA still remain unsatisfactory. Failure patterns and risk factors in RTKA were thoroughly analyzed, with periprosthetic joint infections (PJI) and aseptic loosening remaining at the forefront of re-revision (ReRTKA) causes. While there is evidence that stem profile impacts the revisability of cemented implants, its association with the modes of RTKA failure is unknown.

METHODS

50 consecutive ReRTKA performed in a single orthopedic center during 2016-2017 were retrospectively analyzed. The cases were stratified according to age, sex, number of preexisting revisions, fixation technique, stem design and causes of re-revision. All explanted implants with conical vs. cylindrical stem profiles were compared.

RESULTS

Mean age was 67 ± 11.5, and 54% were females. 72% of the cases had ≥ 3 previous revisions. 88% were full-cemented, 3% hybrid and 9% press-fit stems. 36% of the RTKA had conical, 58% cylindrical and 6% combined stem profiles. 92% of the RTKA components were removed. Removal causes were: PJI (52.2%), aseptic loosening (34.8%), implant malposition (9.8%), painful knee (1.1%) and instability (2.2%). While the overall RTKA failure patterns were equally distributed between conical and cylindrical stems, subgroup analysis of only cemented ReRTKA revealed a higher incidence of aseptic loosening within cylindrical stem profiles (46.7% vs. 25.7%, P = 0.05).

CONCLUSION

Stem profile may have an impact on the process of aseptic loosening in cemented non-metaphyseal engaging RTKA, with cylindrical designs tending to worse outcomes than conical designs. Large cohort studies could provide more clarity on current observation.