Results of Cemented vs Cementless Primary Total Knee Arthroplasty Using the Same Implant Design

Impact of high body mass index on functionally aligned image-based robotic total knee arthroplasty: Comparable functional outcomes but higher mechanical failures

OBJECTIVES

Increased body mass index (BMI) poses challenges in total knee arthroplasty (TKA), including higher complication rates. Functional knee positioning (FKP) with robotic assistance provides a personalized approach to optimize alignment and soft-tissue balance, but its impact on patients with increased BMI remains unclear. This retrospective comparative study aims to evaluate the influence of obesity and its severity on clinical outcomes and complications in TKA performed with an image-based robotic system-guided by FKP principles.

METHODS

This retrospective comparative study included 372 patients who underwent robotic-assisted TKA following FKP principles. Patients were stratified into two main groups based on BMI (<30 ​kg/m2; 238 patients and ≥30 ​kg/m2; 134 patients). Outcomes included Knee Society Scores (KSS), Forgotten Joint Scores (FJS), range of motion (ROM), implant positioning, and complications, evaluated at a minimum follow-up of two years.

RESULTS

Patients with increased BMI (≥30 ​kg/m2) demonstrated similar functional outcomes to patients with BMI <30 ​kg/m2 in terms of ROM, KSS, and FJS. However, the revision rate due to mechanical failures was significantly higher in the obese group (2.99% vs. 0.42%, p ​= ​0.04; hazard ratio ​= ​6.8; 95% CI, 1.09-42.31). Implant positioning was consistent across groups, except for reduced femoral external rotation in the increased BMI group (p ​= ​0.004).

CONCLUSIONS

Robotic-assisted TKA with FKP principles achieves comparable functional outcomes for obese patients at a minimum of a 2-year follow-up, demonstrating the system's ability to address anatomical and functional challenges. However, obesity remains a critical risk factor for mechanical failures.

LEVEL OF EVIDENCE

III.

No difference in 5-year survivorship between cemented versus cementless total knee arthroplasty in a cohort of 5266 patients using a deep-dish mobile bearing implant

PURPOSE

The best fixation method for total knee arthroplasty (TKA) remains controversial. The aim of this study is to compare the effect of cemented and cementless fixation on prosthesis survivorship. Our primary hypothesis is that there is no difference in survivorship between cemented and cementless TKA. Our secondary hypothesis is that there is no difference in aseptic revisions and functional outcomes between cemented and cementless TKA at mid-term follow-up.

METHODS

A multicentre retrospective study was done using data collected prospectively in a large cohort. The same deep-dish mobile bearing design was used for both cemented and cementless TKA. Patients were divided into two groups according to the fixation method. The survival rate between cemented and cementless TKA was compared. Functional outcomes were collected preoperatively and at the 5-year follow-up.

RESULTS

Of the 5266 primary TKA included, 4549 were cementless, and 717 were cemented. At 5 years, there was no significant difference between the survivorship of the cementless (98.7% [95% confidence interval, CI: 98.2-99.1]) and cemented TKA (97.6%, [95% CI: 94.1-99.1]) (p = 0.468). There was no significant difference in the surgery-free survival at 5 years between cementless (95.8% [95% CI: 94.9-96.5]) and cemented TKA (95.5% [95% CI: 92.1-97.5]) (p = 0.508) as well as in aseptic revision: cementless (96.9% [95% CI: 96.2-97.5]) and cemented TKA (97.5 [95% CI: 95.5-98.6]) (p = 0.355). There was no significant difference in the functional outcomes at 5 years.

CONCLUSION

There was no observed difference in survivorship between cemented and cementless TKA at 5 years in this cohort of 5266 patients. Additionally, rates of reoperation and aseptic revision were similar across both fixation methods, and clinical outcomes did not differ significantly. Therefore, it may be suggested that cementless fixation is a safe option for primary TKA.

LEVEL OF EVIDENCE

Level III.

Risk of Early Manipulation in Cemented Versus Cementless Total Knee Arthroplasty: An Analysis of the American Joint Replacement Registry

BACKGROUND

Cementless total knee arthroplasty (TKA) has recently regained popularity, yet data has raised concerns about rates of arthrofibrosis following these procedures. The purpose of this study was to utilize the American Joint Replacement Registry to compare rates of early manipulation under anesthesia (MUA) in cementless and cemented primary TKAs that use technology or manual instrumentation.

METHODS

We queried the American Joint Replacement Registry for all patients ages 18 to 95 years who underwent cemented or cementless primary TKA over a 7-year period. Patients were stratified based on whether technology (robotics or computer-assisted navigation) was used during the primary surgery. Groups were then compared for rates of MUA within 90-day of the index surgery using multivariable logistic regression models. A total of 340,841 cases were included in the study, 78,397 (23%) of which used technology and 262,444 (77%) which did not. Within the technology cohort, there were 51,500 (65%) robotic and 26,897 (35%) navigated cases. There were 65% of technology-assisted TKAs and 92% of manual TKAs cemented.

RESULTS

In the technology group, multivariable analysis demonstrated significantly higher odds of MUA in cemented TKAs compared to cementless (odds ratio [OR] 1.95, 95% confidence interval [CI] [1.06 to 3.59]; P = 0.031). Robotic cases had significantly higher odds of MUA with cemented compared to cementless implants (OR 2.38, 95% CI [1.27 to 4.46]; P = 0.007), while there was no difference in MUA related to cementation in the navigated cases (OR 3.53, 95% CI [0.48 to 25.95]; P = 0.22). In the manual group, there were no significant differences in MUA rates related to cementation use (OR 1.14, 95% CI [0.8 to 1.64]; P = 0.46).

CONCLUSIONS

Cementless TKA did not increase odds of MUA. In further analyzing cement use into technology and manual cohorts, robotic-assisted cemented TKAs had higher rates of early MUA than cementless. Identification of risk factors leading to early arthrofibrosis may be patient dependent and further study is required to elucidate any surgical considerations.

Survivorship of Modern Cementless Total Knee Arthroplasty: Analysis From the Canadian Joint Replacement Registry

BACKGROUND

Cementless total knee arthroplasty (TKA) is rising in popularity. The literature supporting its use over cemented TKA remains sparse. Using the Canadian Joint Replacement Registry (CJRR), we sought to investigate cementless versus cemented fixation in modern primary TKA and (1) determine whether there is an overall difference in revision by fixation, (2) perform a subanalysis of the most-commonly used cementless TKA brand in Canada, and (3) identify the reasons for revision.

METHODS

The CJRR data was used to analyze TKA designs with cemented and cementless versions. Revision risk is reported as all-cause cumulative percent revision (CPR). Reasons for revision were analyzed. Cox proportional hazards models were used to report adjusted hazard ratios (HR) controlling for age, sex, patella resurfacing, and bearing constraints. We included 202,880 primary TKAs performed between 2012 and 2021. Of those, 9,163 (4.5%) were cementless.

RESULTS

The CPR at 8 years was 4.49% for cementless and 3.14% for cemented implants. After adjusting for confounders, we did not detect a difference in revision risk overall (HR 0.87 [95% CI (confidence interval) 0.73 to 1.04], P = 0.128). However, the most commonly used cementless TKA brand demonstrated a CPR of 1.95% compared to 2.19% for its cemented version at 4 years. Furthermore, we detected a significantly lower revision risk compared to its cemented version after adjusting for confounders (HR 0.66 [95% CI 0.51 to 0.85], P = 0.001). The 4 most common reasons for revision in both groups were the following: (1) infection, (2) instability, (3) aseptic loosening, and (4) pain of unknown origin.

CONCLUSIONS

Using CJRR data adjusted for confounding factors, no difference in revision risk was detected between cemented and cementless implants overall. However, for the most common brand of cementless TKA used in Canada, there was a lower risk of revision than its corresponding cemented version. The reasons for revision were similar.

Selective Use of Modern Cementless Total Knee Arthroplasty is Not Associated with Increased Risk of Revision in Patients Aged 65 or Greater: An Analysis from the American Joint Replacement Registry

Modern highly porous surfaces have increased confidence and use of cementless total knee arthroplasty (TKA) in the United States. As cementless TKA use increases, there remains a paucity of literature regarding associated risk of revision in patients aged ≥65 years. We analyzed the American Joint Replacement Registry (AJRR) data from January 2012 to March 2020 identifying patients aged ≥65 years undergoing primary TKA with linked cases to supplemental centers for Medicare and Medicaid data. Patients with hybrid fixation, reverse hybrid fixation, missing component data, highly constrained implants, and stem extension/augmentation were excluded. We identified 442,745 cemented TKAs and 19,841 modern cementless TKAs with a minimum of 2-year follow-up. Cumulative incident function (CIF) curves and cause-specific Cox models evaluated the risk of all-cause revision and revision for mechanical loosening, adjusting for body mass index (BMI), sex, age, cruciate retaining (CR) versus posterior stabilized (PS) femoral design, patellar resurfacing, and Charlson's comorbidity index (CCI). Patients with cementless compared with cemented TKA were younger (mean age: 71.9 vs. 73.2 years, p < 0.001), more likely to be male sex (48.8 vs. 39.0%, p < 0.001), more likely to have a CR femoral design (81.1 vs. 45.7%, p < 0.001), less likely to have patellar resurfacing (92.7 vs. 95.0%, p < 0.001), and had a lower CCI (mean: 2.9 vs. 3.1, p < 0.001). Adjusted hazard ratios (HRs) showed no difference in associated risk for all-cause revision (HR: 1.07; 95% confidence interval [CI]: 0.92-1.24; p = 0.382) or revision for mechanical loosening (HR: 1.38; 95% CI: 0.9-2.12; p = 0.14) for cementless versus cemented TKA. Our results suggest that current selective use of cementless fixation for TKA in patients aged ≥65 years in the United States is not associated with an increased risk of revision. While encouraging, further study is necessary to establish indications for use in this age group prior to broader adoption in this patient population. LEVEL OF EVIDENCE:  Therapeutic Level III.

Cementless fixation in total knee arthroplasty: current evidence and future perspective

INTRODUCTION

Cementless fixation plays an increasing role in total knee arthroplasty (TKA). The objective of this review article is to analyze functional outcomes and survivorship of cementless TKA.

MATERIALS AND METHODS

A comprehensive literature search for studies reviewing the outcome and survivorship of cementless TKA was conducted. This search was based on the PRISMA 2020 guidelines using PubMed, Medline, and Embase. The included studies were screened by two independent observers.

RESULTS

From 2010 to 2022, fifteen studies were included. Eleven studies compared cementless and cemented TKA. Four studies only covered cementless implants. Survivorship and functional outcomes of cementless TKA are at least comparable to those of cemented implants.

CONCLUSION

With improvement in manufacturing, and surgical tools for more precise delivery, such as robotic assisted TKA and 3D-printed implants, one can expect increase in usage of cementless TKA, due to a more biological fixation, better survivorship, and outcomes.

Uncemented Total Knee Arthroplasty is on the Rise. A Report of Patient Demographics and Short-Term Outcomes From the Michigan Arthroplasty Registry Collaborative Quality Initiative

Background

Cemented total knee arthroplasty (TKA) is the gold standard treatment for osteoarthritis, but uncemented TKA offers benefits like improved osseointegration and reduced complications from cement debris. This study aimed to investigate (1) if there has been a rise in uncemented TKA from 2017 to 2021 and (2) if there are differences in early complications between cemented and uncemented TKA.

Methods

A retrospective data review was performed on the Michigan Arthroplasty Registry Collaborative Quality Initiative database of TKA patients from 2017 to 2021 at 6 hospitals. Patients with revision or partial knee arthroplasty were excluded. Patients were divided into 2 groups: uncemented and cemented. Hybrid and reverse hybrid fixation data were collected for incidence, but not for demographics or complications. All patient demographics and 90-day postoperative events were collected and analyzed.

Results

A retrospective study of 18,749 primary TKAs found that 89.7% were cemented, 9.7% uncemented, and 0.7% hybrid or reverse hybrid. Uncemented patients were younger, men, heavier, current smokers, and diabetics than cemented patients (P < .0001, P = .03). They also had a shorter length of stay (P ≤ .0001) and were on fewer preoperative medications: anticoagulants (P = .0059), antiplatelets (P ≤ .0001), opioids (P = .0091), and steroids (P = .0039). The rate of uncemented TKA increased from 3.3% to 17.1%, while the rate of cemented TKA fell from 96.2% to 81.9% (P = .0048). The readmission rate was higher in cemented TKAs (4.0%) than in uncemented TKAs (2.6%) (P = .0048).

Conclusions

The use of uncemented TKA increased from 3.3% in 2017 to 17.1% in 2021, while cemented fixation decreased from 96.7% to 81.9%. There were no significant differences in short-term complications between groups. Uncemented patients were younger, men, took fewer medications, had a shorter length of stay, and were less likely to be readmitted. However, they were more likely to have comorbidities than the cemented group.

Central cone design demonstrates greater micromotion compared to keel design in cementless tibial baseplates: A biomechanical analysis

PURPOSE

The purpose of this study was to compare micromotion of two new cementless tibial baseplates to a cementless design with well-published clinical success.

METHODS

Three cementless tibial baseplate designs (fixed-bearing [FB] with keel and cruciform pegs, rotating-platform with porous central cone and pegs, FB with cruciform keel and scalloped pegs) were evaluated on sawbone models. Loading was applied to the baseplate at a rate of 1 Hz for 10,000 cycles, which represents 6-8 weeks of stair descent. This time frame also represents the approximate time length for the induction of biologic fixation of cementless implants. Compressive and shear micromotion at the sawbone-implant interface were measured.

RESULTS

At the end of the loading protocol, the central cone rotating-platform design exhibited greater micromotion at the anterior (p < 0.001), posterior (p < 0.001) and medial locations (p = 0.049) compared to the other two implants. The central cone design also exhibited greater translational micromotion in the sagittal plane at the medial (p = 0.001) and lateral locations (p = 0.034) and in the coronal plane anteriorly (p = 0.007).

CONCLUSION

The cementless central cone rotating-platform baseplate demonstrated greater vertical and translational micromotion compared to the two FB baseplates with a keel underloading. This may indicate lower initial mechanical stability in implants without a keel, which possibly affects osseointegration. The implication of this is yet unknown and requires further long-term clinical follow-up to correlate these laboratory findings.

LEVEL OF EVIDENCE

V (biomechanical study).

Fixation options for total knee arthroplasty: a comprehensive literature review

Total knee arthroplasty is a consistently successful, cost-efficient, and highly effective surgical procedure for treating severe knee osteoarthritis. The success and longevity of total knee arthroplasty depend significantly on the fixation method used to secure the prosthetic components. This comprehensive review examines the primary fixation methods (cemented, cementless, and hybrid fixation), analysing their biomechanics, clinical outcomes, advantages, and disadvantages, focusing on recent advances and trends in total knee arthroplasty fixation.

Cementless versus Cemented Total Knee Arthroplasty Using the Same Implant Design: A Mean 5-Year Follow-up Study

Cementless implant use continues to increase primarily due to increased numbers of younger and obese patients opting for primary total knee arthroplasty (TKA). Given the increased use of cementless implants, the purpose of this study was to evaluate the midterm clinical performance of cementless TKA using a highly porous tibial baseplate compared with its cemented counterpart of the same system. We conducted a retrospective case-control study of 400 patients undergoing primary TKA that included 200 patients with cementless components matched for age and body mass index (BMI) to 200 patients with cemented implants of the same implant design with a 5-year follow-up. We evaluated clinical results, complications, revisions, and overall survivorship between the cohorts. Statistical analysis was performed using student t-test and chi-square analysis. There was no statistical difference in age (64.3 vs. 64.3 p = 0.81), BMI (34 vs. 33.1 p = 0.19), preoperative Knee Society Score (KSS) function (41 vs. 32.3 p = 0.22), and preoperative KSS knee score (39.2 vs. 38.3 p = 0.54) between the cementless and cemented cohorts, respectively. The cementless group had seven revisions, while the cemented group had nine revisions (p = 0.609). The cementless group had one revision due to aseptic loosening versus five in the cemented group (p = 0.09). Postoperative 5-year KSS knee scores were 92.84 versus 91.75 (p = 0.386) and function scores were 81.81 versus 69.65 (p = 0.00004) in the cementless and cemented groups, respectively. The cementless group had survivorship of 96.5% for all-cause revision compared with 95.5% in the cemented group at 5-year follow-up (p = 0.60). Cementless TKA using a highly porous tibial baseplate showed excellent midterm results with one case of aseptic loosening at 5-year follow-up and with similar Knee Society outcome scores and survivorship compared with the cemented group. Cementless TKA demonstrated noninferiority to cemented TKA and could be used as an alternative mode of fixation in patients opting for primary TKA. Additional long-term follow-up is needed to determine if cementless TKA can demonstrate improved survivorship over cemented TKA.

Cementless Total Knee Arthroplasty: A State-of-the-Art Review

» The demographic profile of candidates for total knee arthroplasty (TKA) is shifting toward younger and more active individuals.» While cemented fixation remains the gold standard in TKA, the interest is growing in exploring cementless fixation as a potentially more durable alternative.» Advances in manufacturing technologies are enhancing the prospects for superior long-term biological fixation.» Current research indicates that intermediate to long-term outcomes of modern cementless TKA designs are comparable with traditional cemented designs.» The selection of appropriate patients is critical to the success of cementless fixation techniques in TKA.» There is a need for high-quality research to better understand the potential differences and relative benefits of cemented vs. cementless TKA systems.

Does the use of tibial stem extensions reduce the risk of aseptic loosening in obese patients undergoing primary total knee arthroplasty: A systematic review and meta-analysis

BACKGROUND

This study aimed to compare the risk of revision for aseptic loosening in obese (body mass index >30 kg/m2) patients with stemmed (ST) versus non-stemmed (NST) tibial implants in primary total knee arthroplasty (TKA).

METHODS

A systematic review and meta-analysis were conducted following PRISMA and MOOSE guidelines. Studies reporting a direct comparison between ST and NST tibial implants in obese patients were included. The primary outcome of interest was revision for aseptic loosening. Outcomes were analysed using meta-analysis of relative risk. Risk of bias assessment was performed using the Newcastle-Ottawa Scale for observational studies and the RoB-2 Cochrane tool for randomised studies.

RESULTS

Seven studies met the selection criteria, consisting of four cohort studies and three randomised controlled trials. Mean follow up time for the eligible cohort was 62.6 months. Meta-analysis demonstrated a statistically significant reduction in the risk of aseptic revision in the ST group compared with the NST group (risk ratio 0.25, 95% confidence interval 0.07 to 0.92). After removal of all zero-event studies, the results remained in favour of the ST group (risk ratio 0.15, 95% confidence interval 0.03 to 0.64).

CONCLUSIONS

This study found that obese patients undergoing TKA with stemmed tibial implants may have a lower risk of aseptic revision compared with those with non-stemmed tibial implants. However, due to the lack of high-quality literature available, our study is unable to draw a definitive conclusion on this matter. We suggest that this topic should be re-evaluated using higher-quality study methods, particularly national joint registries studies and randomised controlled trials.

The Utilization of Press-Fit Total Knee Arthroplasty is Not Evenly Distributed: A National Registry Review

BACKGROUND

This study evaluates trends of cemented versus press-fit total knee arthroplasty (TKA). We hypothesized that press-fit TKA is more common in younger and obese patients. There may also be racial, geographic, and institutional variation.

METHODS

The American Joint Replacement Registry was used to conduct a retrospective review of primary TKA procedures for osteoarthritis in the United States between January 2019 and March 2022. The objective was to identify differences in incidence, demographics, body mass index (BMI), Charlson Comorbidity Index (CCI), and institutional teaching status (teaching vs. non-teaching) between press-fit and cemented TKAs.

RESULTS

Two hundred ninety-seven thousand four hundred two patients (61% female, average age 68 years, 88.3% White) underwent cemented TKA versus 50,880 patients (52% female, average age 65 years, 89% White) underwent press-fit TKA. Overall, 20.8% of press-fit versus 19.9% of cemented TKA had a BMI of 35 to 39.9 and 15.2% of press-fit versus 12.5% of cemented TKA had BMI >40 ( P < 0.001). Patients undergoing press-fit TKA were less likely Black (OR = 0.727; P < 0.0001), Asian (OR = 0.651, P < 0.0001), and Native Hawaiian/other Pacific Islander (OR = 0.705, P < 0.02) with White as the reference group. Northeastern and Southern United States were more likely to use press-fit TKA than the Midwest (OR = 1.89 and OR = 1.87, P < 0.0001) and West (OR = 1.67; and OR = 1.65; P < 0.0001). Press-fit TKA incidence in 2019 was 9.9% versus 20.6% in 2022 ( P < 0.001).

CONCLUSION

Press-fit TKA is increasingly more common in Northeastern and Southern United States, and patients are older than expected. Patients with BMI >35 had a slightly higher rate of undergoing press-fit than cemented TKA. Notable racial differences also exist. Additional research addressing racial disparities and evaluating longevity of press-fit designs is needed.

Survivorship and complications of cementless compared to cemented posterior-stabilized total knee arthroplasties: A systematic review and meta-analysis

PURPOSE

Controversy exists on the best fixation for total knee arthroplasty (TKA). Non-cemented fixation has been theorized to improve patient outcomes and longevity of implantation but no study has focused on comparison between cemented or cementless posterior-stabilized implants despite being the most commonly or second most frequently utilized implant in most total knee replacement registries.

METHODS

Inclusion criteria with observational and interventional papers, and review articles that focused on patients with cementless and cemented PS TKAs were used to analyze outcomes such as implant survivorship, complication, or revision rates. Using a combination of keywords, a systematic search was performed on Medline (PubMed), Embase, and Cochrane Library for Meta-Analysis.

RESULTS

When using the specified criteria, only 8 studies were selected for full-text analysis and meta-analysis after eliminating screening duplicates, titles, and abstracts without full-text access. These eight studies contain 1652 patients, 693 in the non-cemented Group, and 959 in the cemented total knee prosthesis Group. The meta-analysis revealed the advantage of cementless fixation over cemented fixation in implant survivorship, with 0.6% and 2.6% of aseptic loosening in each Group. The cumulative survival at 12 years was 97.4% for the cementless Group and 89.2% for the cemented Group. The subgroup with a stem showed a positive outcome for cementless fixation over cemented fixation regarding implant survivorship. No differences between the cemented and cementless TKAs were observed in patient-reported outcomes, revision rates, or radiolucent line development.

CONCLUSION

We observed comparable rates for cemented and cementless posterior-stabilized TKAs over a medium-term follow-up period.

Cementless and Cemented Total Knee Arthroplasties Have Similar Outcomes but Cementless Patellar Component Migration was Observed in a Paired Randomized Control Trial

BACKGROUND

Cementless total knee arthroplasty (TKA) has become increasingly popular. Some surgeons are concerned about pain, implant stability, and metal-backed patellar component survivorship. This study investigated the outcomes of cementless compared with cemented TKA in bilateral cases.

METHODS

We randomized 80 knees in 40 osteoarthritic knee patients who underwent bilateral TKA with patellar resurfacing under one anesthesia. All participants received cementless prostheses in one knee and cemented prostheses in the other. The outcomes were knee function measured by the forgotten joint scores, modified Western Ontario and McMaster Universities Osteoarthritis Index, knee ranges of motion, pain levels, operative times, radiographic outcomes, and complications. All knees were followed for a minimum of 2 years (2 to 3 years).

RESULTS

Cementless and cemented TKA had similar functional outcomes in forgotten joint score (97 ± 5 versus 98 ± 3 points, P = .52), modified Western Ontario and McMaster Universities Osteoarthritis Index score (3 ± 4 versus 3 ± 2 points, P = .96), and ranges of motion (134 ± 7° versus 134 ± 7°, P = .16). The postoperative pain was also similar (P > .05). There were 4 cementless patellar components had superior migration for an average of 3.5 mm (range, 1.77 to 4.16) without loosening. The mean time of migration was 4 (range, 2 to 6) weeks.

CONCLUSIONS

Cementless TKA had similar functional outcomes and recovery patterns compared with cemented TKA. However, there was concern of cementless component migration at patellae.

Four-Year Outcomes of Cementless Versus Cemented Fixation of a Newly Introduced Total Knee Arthroplasty Design

BACKGROUND

Aseptic loosening continues to be a major cause of failure of total knee arthroplasty (TKA). Although cemented fixation remains the gold standard, there is renewed interest in cementless fixation as a means of decreasing this risk via biologic fixation. The purpose of this study was to evaluate the clinical outcomes of cemented and cementless versions of a newly introduced TKA design at an average of 4 years postoperatively.

MATERIALS AND METHODS

This was a retrospective case-control study of 100 primary TKAs comparing cementless vs cemented TKAs using the same cruciate-retaining implant design (ATTUNE Knee System; DePuy Synthes). Fifty patients undergoing cementless TKA with a mean age of 60.8 years (range, 48-71 years) and body mass index (BMI) of 31.6 kg/m2 (range, 23.7-41.9 kg/m2) were matched to 50 patients undergoing primary cemented TKA with a mean age of 62.7 years (range, 51-73 years) and BMI of 30.1 kg/m2 (range, 24.6-43.9 kg/m2). The mean follow-up was 4.2 years (range, 4.0-4.4 years) in the cementless group and 7.6 years (range, 7.5-7.7 years) in the cemented group. Complications, clinical outcomes using the Knee Society Score (KSS), and radiographic analyses were evaluated at final follow-up. Student's t tests were used for statistical analyses.

RESULTS

There was no statistical difference in age, BMI, and preoperative KSS between the two groups (P=.12, P=.15, and P=.55, respectively). There were no complications or reoperations in either cohort. There were no statistical differences in range of motion and total KSS at final follow-up between the two groups. Final total KSS had a mean of 91.1 for the cementless group and 93.7 for the cemented group. There was no radiographic evidence of component subsidence or loosening in either cohort.

CONCLUSION

When compared with its cemented counterpart, the newly introduced cementless TKA design had similar excellent clinical improvements and radiologic results at an average of 4 years of follow-up. [Orthopedics. 2024;47(3):161-166.].

Cemented is not superior to cementless total knee arthroplasty for complications: a propensity score matched analysis

INTRODUCTION

There is continued debate regarding the survivorship and revision rate of cementless versus cemented total knee arthroplasty (TKA) prostheses. This includes the assessment of early revision surgery due to aseptic loosenings and periprosthetic joint infections (PJIs). Studies have not always taken into account the impact of comorbidities, such as diabetes, obesity, and tobacco. Therefore, we compared revisions in a large population of patients undergoing cemented or cementless TKAs at 90 days, 1 year, and 2 years.

METHODS

A review of an administrative claims database was used to identify patients undergoing primary TKA, either cementless (n = 8,890) or cemented (n = 215,460), from October 1, 2015 to October 31, 2020. Revision surgery for PJI and aseptic loosening were identified with diagnosis and associated procedural codes at 90 days, 1 year, and 2 years and then compared between groups. A propensity matched-analysis was performed for age, sex, Charles Comorbidity Index (CCI) > 3, alcohol abuse, tobacco use, obesity, and diabetes. Chi square tests assessed statistical significance of differences in the matched cohorts using odds ratios (ORs) with 95% confidence intervals (CIs). A P < 0.05 was defined as statistically significant.

RESULTS

Cementless TKA was associated with similar revisions rates due to PJIs at 90 days (OR, 1.04, 95% CI 0.79-1.38, p = 0.83), 1 year (OR, 0.93, 95% CI 0.75-1.14, p = 0.53, and 2 years (OR, 0.87, 95% CI 0.73-1.05, p = 0.17) in comparison to the cemented TKA cohort. The odds ratio of revision due to aseptic loosening was similar as well at 90 days (OR, 0.67, 95% CI 0.34-1.31, 0.31), 1 year (OR, 1.09, 95% CI 0.73-1.61, p = 0.76), and 2 years (OR, 1.00, 95% CI 0.73-1.61, p = 0.99).

CONCLUSIONS

This study found a comparable risk of PJI and aseptic loosening in cementless and cemented TKA when controlling for several comorbidities, such as tobacco, diabetes, and alcohol. Therefore, with proper patient selection, cementless TKAs can be performed with expectation of low risks of infections and aseptic loosenings.

Cementless Versus Cemented Total Knee Arthroplasty of the Same Design: Shorter Operative Times and Minimal Differences in Early Outcomes

Introduction: Modern primary cementless total knee arthroplasty (TKA) is increasingly popular, but there is limited evidence on its benefits, early complications, and failures. Purpose: We sought to evaluate operative time, early survivorship, and outcomes of cementless versus cemented TKA of the same design. Methods: As part of this single-center, multisurgeon, retrospective cohort study, we reviewed 598 primary, unilateral TKAs (170 cementless, 428 cemented) of the same design from 2016 to 2018. The cementless cohort was younger (63 vs 67 years) and had more cruciate-retaining implants (17% vs 12%) compared with the cemented cohort. We compared operative time, length of stay, and complications. Survivorship curves were generated via the Kaplan-Meier method. Results: Patients with cementless TKA (using the Triathlon implant, Stryker) had a 24% reduction in operative time (83 vs 109 minutes) but similar length of stay compared with those with cemented TKA (57 vs 61 hours). Cementless TKA had a higher rate of postoperative manipulation for stiffness compared with cemented TKA (8% vs 3%), but there were notable demographic differences between the cohorts. Despite 2 cases (1%) of early cementless tibial aseptic loosening requiring component revision compared with none in the cemented cohort, there was no difference in revision-free survivorship at 2 years (96% and 98%, respectively). Conclusion: This retrospective cohort study found that cementless TKA had a 24% reduction in operative time compared with cemented TKA and similar short-term survivorship. There was a slightly higher rate of aseptic revision and manipulation in the cementless cohort. Further study is warranted on the long-term durability of cemented and cementless TKAs to determine if cementless fixation proves more durable in the midterm to long term.

Trend of using cementless total knee arthroplasty: a nationwide analysis from 2015 to 2021

BACKGROUND

Modern cementless total knee arthroplasty (TKA) fixation has shown comparable long-term outcomes to cemented TKA, but the trend of using cementless TKA remains unclear. This study aimed to investigate the trend of using cementless TKA based on a national database.

METHODS

The patients undergoing cementless TKA between 2015 and 2021 were retrospectively extracted from the PearlDiver (Mariner dataset) Database. The annual percentage of cementless TKA was calculated using the following formula: annual number of cementless TKA/annual number of TKA. The trend of the number of patients undergoing cementless TKA was created according to a compounded annual growth rate (CAGR) calculation of annual percentages. Patient age, comorbidity, region, insurance type, etc., were also investigated. Differences were considered statistically significant at P < 0.05.

RESULTS

Of the 574,848 patients who received TKA, 546,731 (95%) underwent cemented fixation and 28,117 (5%) underwent cementless fixation. From 2015 to 2021, the use of cementless TKA significantly increased by 242% from 3 to 9% (compounded annual growth rate (CAGR): + 20%; P < 0.05). From 2015 to 2021, we observed a CAGR greater than 15% for all age groups (< 50, 50-59, 60-69, 70-74, 75 +), insurance types (cash, commercial, government, Medicare, Medicaid), regions (Midwest, Northeast, South, West), sex (male and female), and certain comorbidities (osteoporosis, diabetes mellitus, tobacco use, underweight (BMI < 18.5), rheumatoid arthritis) (P < 0.05 for all). Patients undergoing TKA with chronic kidney disease, prior fragility fractures, and dementia demonstrated a CAGR of + 9%-13% from 2015 to 2021 (P < 0.05).

CONCLUSION

From 2015 to 2021, the use of cementless TKA saw a dramatic increase in all patient populations. However, there is still no consensus on when to cement and in whom. Clinical practice guidelines are needed to ensure safe and effective use of cementless fixation.

New Horizons of Cementless Total Knee Arthroplasty

BACKGROUND

Considering the increasing number of young and active patients needing TKA, orthopedic surgeons are looking for a long-lasting and physiological bond for the prosthetic implant. Multiple advantages have been associated with cementless fixation including higher preservation of the native bone stock, avoidance of cement debris with subsequent potential third-body wear, and the achievement of a natural bond and osseointegration between the implant and the bone that will provide a durable and stable fixation.

DISCUSSION

Innovations in technology and design have helped modern cementless TKA implants to improve dramatically. Better coefficient of friction and reduced Young's modulus mismatch between the implant and host bone have been related to the use of porous metal surfaces. Moreover, biologically active coatings have been used on modern implants such as periapatite and hydroxyapatite. These factors have increased the potential for ingrowth by reducing micromotion and increasing osteoconductive properties. New materials with better biocompatibility, porosity, and roughness have been introduced to increase implant stability.

CONCLUSIONS

Innovations in technology and design have helped modern cementless TKA implants improve primary stability in both the femur and tibia. This means that short-term follow-up are comparable to cemented. These positive prognostic factors may lead to a future in which cementless fixation may be considered the gold-standard technique in young and active patients.

Cemented total knee arthroplasty provides greater knee range of motion at 2 years than cementless technique

INTRODUCTION

Optimal fixation method between cemented, cementless, and hybrid techniques for total knee arthroplasty (TKA) is still debated. The purpose of this study is to evaluate the clinical outcomes of patients undergoing cemented versus cementless TKA.

METHODS

We reviewed 168 patients who underwent a primary TKA at a single academic institution between January 2015 and June 2017. Patients were categorized into cemented (n = 80) or cementless (n = 88) groups. Only patients with greater than or equal to 2-year follow-up were included in the study. Multivariate regressions were performed to analyze the relationship between the surgical fixation technique and the clinical outcomes.

RESULTS

There were no differences in demographics or baseline operative characteristics between the two groups. The cemented group had fewer manipulations under anesthesia (MUA) (4 vs. 15, p = 0.01), longer intraoperative tourniquet times (101.30 vs. 93.55 min, p = 0.02), and increased knee range of motion (ROM) at final follow-up (111.48 vs. 103.75°, p = 0.02) compared to the cementless group.

DISCUSSION AND CONCLUSION

Both cemented and cementless component fixation are viable options for (TKA). This study found that patients who underwent a cemented TKA required fewer MUA's and had greater final ROM compared to patients undergoing cementless TKA. Additional research is required regarding cementless and cemented fixation. We believe that the choice of which fixation technique to use ultimately comes down to patient characteristics and surgeon preference.

Cementless Versus Cemented Total Knee Arthroplasty: Concise Midterm Results of a Prospective Randomized Controlled Trial

BACKGROUND

We previously reported the 2-year results of a prospective randomized controlled trial of cementless versus cemented total knee arthroplasty (TKA) implants of the same design. The purpose of the present study was to provide concise results at intermediate-term follow-up.

METHODS

The original study included 141 TKAs (76 performed without cement and 65 performed with cement). Since then, 8 patients died and 4 withdrew. Of the remaining 129 patients, 127 (98%) were available for analysis. Survivorship analysis was performed; Oxford Knee, Knee Society, and Forgotten Joint Scores were calculated; and radiographs reviewed. Mean follow-up was 6 years.

RESULTS

The survivorship free of any revision was 100% in both groups. There were no differences between the groups in any patient-reported functional outcome measure (p = 0.2 to 0.5). However, a higher percentage of patients in the cementless TKA group were either extremely or very satisfied with their overall function (p = 0.01). Radiographically, there was no evidence of implant loosening in either group.

CONCLUSIONS

At 6 years, there were no differences between cementless and cemented TKA implants of the same design in terms of survivorship, clinical, or radiographic outcomes.

LEVEL OF EVIDENCE

Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

Cementless Total Knee Arthroplasty is Associated With Early Aseptic Loosening in a Large National Database

BACKGROUND

Despite excellent longevity demonstrated in institutional studies, outcomes after cementless total knee arthroplasty (TKA) on a population level remain unknown. This study compares 2-year outcomes between cemented and cementless TKA using a large national database.

METHODS

A large national database was used to identify 294,485 patients undergoing primary TKA from January 2015 to December 2018. Patients who had osteoporosis or inflammatory arthritis were excluded. Cementless and cemented TKA patients were matched one-to-one based on age, Elixhauser Comorbidity Index, sex, and year yielding matched cohorts of 10,580 patients. Outcomes at 90 days, 1 year, and 2 years postoperatively were compared between groups, and Kaplan-Meier analysis was used to evaluate implant survival rates.

RESULTS

At 1 year postoperatively, cementless TKA was associated with an increased rate of any reoperation (odds ratio [OR] 1.47, 95% confidence interval [CI] 1.12-1.92, P = .005) compared to cemented TKA. At 2 years postoperatively, there was an increased risk of revision for aseptic loosening (OR 2.34, CI 1.47-3.85, P < .001) and any reoperation (OR 1.29, CI 1.04-1.59, P = .019) after cementless TKA. Two-year revision rates for infection, fracture, and patella resurfacing were similar between cohorts.

CONCLUSION

In this large national database, cementless fixation is an independent risk factor for aseptic loosening requiring revision and any reoperation within 2 years after primary TKA.

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.

Cementless and Cemented Dual-pivot Total Knee Arthroplasty: A Matched Comparison with a Minimum Two-year Follow-up

INTRODUCTION

With the use of newer biomaterials, many authors have reported similar results between cementless and cemented total knee arthroplasty (TKA). The purpose of this study was to compare the early clinical and radiographic outcomes of cementless and cemented TKA using the same dual-pivot articulation.

METHODS

A consecutive series of 806 TKAs were implanted by a single surgeon using the same dual-pivot articulation. There were 634 TKAs (79%) cemented and 172 (21%) uncemented. One patient in the cementless group was lost before two years. The remaining 171 cementless TKAs were matched 1:1 with cemented TKAs with respect to age, sex, and body mass index (BMI). All patients were followed for a minimum of two years (range, 24 to 66 months) using the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS, JR), and Knee Society clinical and radiographic evaluation. The average follow-up was 3.8 years (range, 24-66 months) in the cemented group and 3.4 years (range,24-56 months) in the cementless group.

RESULTS

At final follow-up, the average KOOS-JR score was higher in the cementless group (86 points (range, 64-100) vs. 80 points (range, 57-100). Post-op Knee Society scores (including pain and function) were similar. There was one deep infection (cemented TKA). The manipulation rate was 1.2% in the cementless group and 2.4% in the cemented TKA group. Excluding infection, two knees (1.2%) were revised in each group. No cases of femoral or tibial component loosening were identified.

CONCLUSION

Patients implanted with either a cemented or cementless TKA using the same conforming dual-pivot articulation design had similar early outcomes and functional improvements. The type of fixation did not appear to influence the early clinical results.

Cementless Total Knee Arthroplasty Over the Past Decade: Excellent Survivorship in Contemporary Designs

BACKGROUND

Cementless fixation in total knee arthroplasty (TKA) is re-emerging due to improvements in biomaterials, surgical technique, and implant design. Albeit rare, failure of osseointegration typically occurs within the first 2 years, and limited data exist on survivorship of the modern cementless TKA designs. This study evaluated clinical survivorship of 2 contemporary cementless TKA designs at minimum 2-year follow-up.

METHODS

A total of 627 cementless TKAs were performed up to July 2022. Three hundred thirty-nine cases were eligible for 2-year follow-up. Indications centered around bone quality and involved predominantly younger patients. The 2 designs consisted of tibial components with a highly porous titanium ingrowth surface, a central keel, and peripheral cruciform pegs with a porous cobalt-chromium femur. Survivorship estimates were calculated using right-censored non-parametric Kaplan-Meier methodologies. A total of 226 TKAs obtained minimum 2-year follow-up with a mean of 3.6 years (range, 2 to 10).

RESULTS

The all-cause revision rate was 2.4% (8 of 339). The revision rate due to aseptic loosening was 0.6% (2 of 339) consisting of 2 femoral components. No tibial components were revised for aseptic loosening. Kaplan-Meier survivorship free from aseptic loosening was 99% (95% confidence interval 98 to 100) at a maximum of 10 years.

CONCLUSION

These results demonstrate encouraging survivorship of cementless fixation in primary TKA with use of contemporary ingrowth biomaterials and modern implant designs. This particular tibial implant design with a highly porous titanium fixation surface, central keel, and peripheral cruciform pegs demonstrated excellent clinical survivorship without failure which may portend superior fixation.

LEVEL OF EVIDENCE

IV-case series, no control group/historical control group.

No component loosening of a cementless deep dish rotating platform knee at a 5-year follow-up

PURPOSE

Cemented fixation remains the gold standard in total knee arthroplasty. With an increasing number of younger patients undergoing total knee arthroplasty and a growing patient population demanding higher physical activity, a rising interest in discussion of cementless fixation is notable. The current scientific literature does not give a clear recommendation for or against uncemented total knee arthroplasty. The purpose of this study was the investigation of the 5-year clinical and radiographic outcomes of a cementless deep-dish rotating platform implant.

METHODS

A total of 91 primary cementless total knee arthroplasties were included in this single-centre prospective observational study. The primary outcome was revision rate due to aseptic component loosening. Further outcome measures were assessment of the of the radiographic outcome as well as the clinical outcome based on Range of Motion and scores such as American Knee Society Score, Oxford Knee Score, Knee Injury and Osteoarthritis Outcome Score and European Quality of Life 5 Dimension 3 Level at a follow-up of 5 years.

RESULTS

Mean age of the study population was 67.3 ± 6.6 years with 49.5% of the participants being female. Aseptic component loosening occurred in none of the patients. Implant survival with revision for any reason as endpoint was 97.8% (95% CI 100-96%) and 95.6% (95% CI 100-94%) with reoperation of any cause as endpoint. Radiolucent lines were detected in a total of eight cases (8.8%) and disappeared within the first year after surgery in five cases. Total Range of Motion improved significantly from 106° ± 15° preoperatively to 118° ± 10° at final FU (p < 0.001). All investigated scores improved significantly after total knee arthroplasty.

CONCLUSION

The results of this study reveal excellent mid-term performance of a cementless deep dish rotating platform total knee implant, with no component loosening, very low overall revision rate, only temporarily present radiolucent lines in a minority of patients and excellent clinical results. Therefore, cementless total knee arthroplasty is an appropriate treatment option for patients with severe osteoarthritis of the knee.

LEVEL OF EVIDENCE

Level II (prospective cohort study).

The Knee-Fix study: study protocol for a randomised controlled trial evaluating cemented and cementless components in total knee arthroplasty

BACKGROUND

Total knee arthroplasty (TKA) is an effective procedure for patients with a variety of knee conditions. The main cause of aseptic TKA failure is implant loosening, which has been linked to poor cement mantle quality. Cementless components were introduced to offer better longer-term biological fixation through osseointegration; however, early designs led to increased rate of revision due to a lack of initial press-fit and bony ingrowth. Newer highly porous metal designs may alleviate this issue but randomised data of fully uncemented TKA (tibial, femoral, patella) is lacking. The aim of the Knee-Fix study is to investigate the long-term implant survival and patient outcomes of fully uncemented compared with cemented fixation in TKA. Our study hypothesis was that uncemented TKA would be as clinically reliable and durable as the gold-standard cemented TKA.

METHODS

The Knee-Fix study is a two-arm, single-blinded, non-inferiority randomised controlled trial with 160 patients in each arm and follow-up at 6 weeks, 6 months, 12 months, 24 months, 5 years and 10 years. The primary outcome of interest is implant fixation, which will be measured by assessment of postoperative progressive radiolucencies with the Knee Society Total Knee Arthroplasty Roentgenographic Evaluation and Scoring System. Secondary outcome measures are patient-reported outcomes, measured using Oxford Knee Score (OKS), International Knee Society System (IKSS), Forgotten Joint Score-12 (FJS-12), EuroQol (EQ-5D-5L), VAS Pain, Patient Satisfaction Score and Net Promoter Score.

DISCUSSION

While cemented fixation remains the gold standard, a growing proportion of TKA are now implanted cementless. Highly porous metal cementless components for TKA can offer several benefits including potentially improved biological fixation; however, long-term outcomes need further investigation. This prospective study will help discern long-term differences between the two techniques.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry ACTRN12616001624471 . Registered trial name: Knee-Fix study (Cemented vs Uncemented Total Knee Replacement). Registered on 24 November 2016.

Short-term results of the uncemented triathlon total knee arthroplasty: a large cohort single-centre comparative study

BACKGROUND

The purpose of this study is to assess the short-term survivorship of a new uncemented TKA design in a high-volume centre to evaluate the safety of this design prior to widespread adoption.

METHODS

We performed a retrospective cohort study of all primary TKAs (cemented and uncemented) between May 2018 and May 2019. Primary outcome variables included aseptic revision, all-cause revision, time to revision, operative time and radiological outcomes. Predictor variables considered included age, gender, BMI, ASA, implant type (cruciate-retaining, posterior-stabilised or totally-stabilised) and the use of cemented or uncemented implants.

RESULTS

There were 300 cemented TKAs and 249 uncemented TKAs (Triathlon, Stryker Inc., Mahwah, NJ) implanted. The mean follow-up for all cases was 31.6 months (minimum follow-up 2 years). Of the entire 549 implants only 4 were revised. Two of these were for infection, 1 was for patellar maltracking and 1 was for knee stiffness. All 4 revisions occurred in the cemented cohort. The aseptic revision rate in the cemented cohort was 0.7% compared to 0.0% in the uncemented cohort (p = 0.298). Operative times were significantly reduced in the uncemented cohort from 57.9 to 51.7 min (p < 0.001). There were 8/300 (2.6%) patients with RLLs in the cemented cohort and 4/249 (1.6%) patients with RLLs in the uncemented cohort (p = 0.56).

CONCLUSION

The uncemented Triathlon TKA demonstrates excellent survivorship at short-term follow-up when compared to the cemented Triathlon TKA, thus eliminating any potential clinical concerns with this novel implant in the early post-operative phase.

Multiacquisition Variable-Resonance Image Combination Magnetic Resonance Imaging to Study Detailed Bone Apposition and Fixation of Cementless Knee System Compared to Cemented Total Knee Replacements

Background

Methods

Results

Conclusions

Cemented Total Knee Arthroplasty Shows Less Blood Loss but a Higher Rate of Aseptic Loosening Compared With Cementless Fixation: An Updated Meta-Analysis of Comparative Studies

BACKGROUND

The aim of this study was to update the current evidence on functional outcomes, complications, and reoperation rates between cemented and cementless total knee arthroplasty (TKA) by evaluating comparative studies published over the past 15 years.

METHODS

The PubMed, MEDLINE, Scopus, and the Cochrane Central databases were used to search keywords and a total of 18 studies were included. Random and fixed effect models were used for the meta-analysis of pooled mean differences (MDs) and odds ratios (ORs).

RESULTS

A total of 5,222 patients were identified with a mean age of 64.4 ± 9.4 and 63 ± 8.6 years for the cemented and cementless TKA groups, respectively. The mean follow-up was 107.9 ± 30 and 104.3 ± 10 months for the cemented and cementless TKA groups, respectively. Cemented TKA showed a significantly greater postoperative Knee Society Score (MD = -0.95, 95% CI [-1.57, 0.33], P = .003) and range of motion (MD = -1.09, 95% CI [-1.88, -0.29], P = .0007), but no differences in other outcome scores were found. The incidence of periprosthetic joint infection, radiolucent lines, instability, and polyethylene wear was also comparable. Cemented TKA showed less perioperative blood loss (SMD = -438.41, 95% CI [-541.69, -35.14], P < .0001) but a higher rate of manipulation under anesthesia (OR = 3.39, 95% CI [1.64, 6.99], P = .001) and aseptic loosening (OR = 1.62, 95% CI [1.09, 2.41], P = .02) than cementless TKA. No differences were found in terms of the reoperation rate.

CONCLUSION

When cemented and cementless fixations are compared in primary TKA, comparable functional outcomes and reoperation rates can be achieved. Cemented TKA showed less blood loss but a higher rate of manipulation under anesthesia and aseptic loosening.

Evolving etiologies and rates of revision total knee arthroplasty: a 10-year institutional report

Background

The number of total knee arthroplasties (TKA) performed in the United States is projected to rise significantly, with a proportionate increase in the revision burden. Understanding the mechanism of failure in primary TKA is important as etiologies continue to evolve and reasons for revision change. The purpose of this study was to determine the reason for revision TKA at our institution among early and late failures and assess if the etiology has changed over a 10-year time-period.

Methods

We identified 258 revision TKAs performed at our institution between 2005 and 2014. Reasons for revision TKA were categorized according to diagnosis. We also conducted subgroup analysis for TKA revisions performed within two years of the primary TKA (early failures) and those performed after two years (late failures). Revision TKAs were also grouped by year of primary TKA (before and after 2000) and time period in which the revision TKA was performed (2005–2009 and 2010–2014).

Results

The most common reason for revision TKA was infection (29.3%), followed by aseptic loosening (19.7%), which together accounted for half of all revisions. Other indications for revision were instability (11.6%), osteolysis (10.4%), arthrofibrosis (8.1%), polyethylene (PE) wear (7.7%), malalignment/malposition (5.4%), patellar complication (3.1%), periprosthetic fracture (2.3%), pain (1.5%), and extensor mechanism deficiency (0.8%). Nearly half of early failures (47%) were due to infection. Osteolysis and PE wear made of a significantly higher proportion of revisions of TKAs performed prior to 2000 compared to index TKAs performed after 2000.

Conclusion

At our institution, infection was the most common reason for revision TKA. Infection had a higher rate of early revisions. Proportion of TKAs revised for osteolysis and PE wear was higher for TKAs performed prior to 2000. Proportion of revision TKA for infection and instability were higher with TKAs performed after 2000.

Clinical outcomes and survivorship of cementless triathlon total knee arthroplasties: a systematic review

Background

Over the last decade, cementless total knee arthroplasty has demonstrated improved outcomes and survivorship due to advances in technologies of implant design, manufacturing capabilities, and biomaterials. Due to increasing interest in cementless implant design for TKA, our aim was to perform a systematic review of the literature to evaluate the clinical outcomes and revision rates of the Triathlon Total Knee system over the past decade.

Methods

A systematic review of the literature was conducted following PRISMA guidelines for patients who underwent total knee arthroplasty with cementless Triathalon Total Knee System implants. Patients had a minimum of two-year follow-up and data included clinical outcome scores and survivorship data.

Results

Twenty studies were included in the final analysis. The survivability of the Stryker Triathlon TKA due to all causes was 98.7%, with an aseptic survivability of 99.2%. The overall revision incidence per 1,000 person-years was 3.4. Re-revision incidence per 1,000 person-years was 2.2 for infection, and 1.3 for aseptic loosening. The average KSS for pain was 92.2 and the average KSS for function was 82.7.

Conclusions

This systematic review demonstrated excellent clinical outcomes and survivorship at a mean time of 3.8 years. Additional research is necessary to examine the long-term success of the Stryker Triathlon TKA and the use of cementless TKAs in obese and younger populations.

Level of evidence

III.

A Short-Term Multicenter Analysis of Radiolucent Lines in a Single Uncemented Rotating Platform Implant for Total Knee Arthroplasty

Background

Uncemented total knee arthroplasty is increasing as a potential solution for aseptic loosening via biologic fixation and to increase operative efficiency. However, postoperative radiolucent lines (RLLs) remain a concern for some clinicians. We report on a multicenter analysis of these RLLs over a 2-year period to identify their incidence, progression, and clinical significance.

Material and methods

Institutional review board approval was obtained for this retrospective, multicenter case series. A total of 312 patients treated with a single cruciate-retaining, fully porous coated femoral and tibial component design were included in the study. All patients were evaluated clinically and radiographically in the early postoperative period and at final follow-up (average 2.0 years). Average age of the study group was 58.2 years, and average body mass index was 30.7. Of the total, 66% were male, and 34% were female. Two independent surgeons evaluated the radiographs at the initial postoperative visit and at the most recent follow-up for RLLs. Knee Society Scores and range of motion (ROM) were collected at each visit.

Results

We identified RLLs in 25% of patients. All RLLs were less than 1 mm in size and located at the periphery of the tibial implant. None of the RLLs were progressive. At the final follow-up, compared with early postoperative imaging, no new RLLs were identified. Average ROM in flexion was 124 degrees, and the average Knee Society Scores at the most recent clinical follow-up was 96.

Conclusion

RLLs are commonly seen following cementless TKA, most commonly underneath the tibial tray. Based on this data set, there does not appear to be progression of these RLLs with time, and they do not appear to have an effect on ROM or clinical outcome at 2 years.

Finite element analysis of a hybrid corrugated hip implant for stability and loading during gait phases

Implants used in total hip replacements (THR) exhibit high failure rates and up to a decade of operational life. These surgical failures could be mainly attributed to the improper positioning, post-surgical stability and loading, of the implants during different phases of the gait. Typically, revised surgeries are suggested within a few years of hip implantation, which requires multiple femoral drilling operations to remove an existing implant, and to install a new implant. The pain and trauma associated with such procedures are also challenging with the existing hip implants. In this work, we designed a novel corrugated hip implant with innovative dimensioning as per ASTM standards, and grooves for directed insertion and removal (using a single femoral drilling and positioning operation). Biocompatible titanium alloy (Ti6Al4V) was chosen as the implant material, and the novel implant was placed into a femur model through a virtual surgery to study its stability and loading during a dynamic gait cycle. A detailed mesh convergence study was conducted to select a computationally accurate finite element (FE) mesh. Tight fit and frictional fit attachment conditions were simulated, and the gait induced displacements and stresses on the implant, cortical and cancellous bone sections were characterized. During walking, the implant encountered the maximum von-Mises stress of 254.97 MPa at the femoral head. The analyses indicated low micro-motions (i.e., approximately 7μm) between the femur and implant, low stresses at the implant and bone within elastic limits, and uniform stress distribution, which unlike existing hip implants, would be indispensable for bone growth and implant stability enhancement, and also for reducing implant wear.

Clinical Results in Posterior-Stabilized Total Knee Arthroplasty with Cementless Tibial Component in Porous Tantalum: Comparison between Monoblock and Two Pegs vs. Modular and Three Pegs

Nowadays, total knee arthroplasty (TKA) is widely considered to be the gold standard for treatment of end-stage knee osteoarthritis. Although the optimal mode of fixation in TKA continues to be an important area of investigation, cementless fixation offers the possibility to gain biologic fixation, preserve bone stock and mineral density, and potentially improve survivorship. The purpose of this retrospective study was to evaluate the clinical results of a posterior-stabilized total knee arthroplasty with cementless tibial component in porous tantalum, comparing two groups: Group A (30 patients), TKA with a monoblock component and two pegs, and Group B (22 patients), with a modular component and three pegs. Knee Society Score (KSS) and the Knee Injury and Osteoarthritis Outcome Score (KOOS) were submitted to the patients, and radiographs were collected at the last follow-up. The mean follow-up was 26.32 (20–40) months. Significant differences were not detected between the postoperative KSS values in the two groups (p = 0.44). Evaluating KOOS outcomes, we found in Group A that the rating system showed a statistically significant improvement from a preoperative average rating of 51.4 (SD ± 15) to an average of 72.66 (SD ± 19) at final follow-up (p < 0.05). In Group B, the KOOS rating system showed a statistically significant improvement from a preoperative average rating of 48.3 (SD ± 18) to an average of 79.54 (SD ± 17) postoperatively (p < 0.05). Comparing KOOS final outcomes between groups, we found no statistically significant difference at the mean final follow-up (p = 0.20), with the exception of the sport-related section (p < 0.05). Radiological evaluation at the final follow-up did not show any sign of polyethylene wear, radiolucency, septic or aseptic loosening, or change in alignment in either group. The current study demonstrates an excellent survivorship of cementless tibial components in porous tantalum and the possibility of osseous integration, without significant differences between the two groups under investigation.

Cemented Versus Noncemented Total Knee Arthroplasty Outcomes

INTRODUCTION

Aseptic loosening remains one of the most common indications for revision total knee arthroplasty (TKA). Given the demographic shift to a younger and more active TKA patient population, some surgeons have revisited noncemented fixation given its potential for lower rates of long-term aseptic loosening. The purpose of this study was to compare the demographics and complications between patients undergoing noncemented and cemented TKA.

METHODS

Using the MKnee subset of the PearlDiver database, diagnosis and procedure codes were used to identify patients who had undergone cemented or noncemented TKA for osteoarthritis with a minimum 2-year follow-up. Propensity score matching was done to compare risk-adjusted medical and surgical complication profiles at 90 days, 1 year, and 2 years.

RESULTS

Of 203,574 patients identified, 3.2% underwent noncemented TKA and 96.8% underwent cemented TKA. Using propensity-matched analysis, there was no difference in 90-day medical complications. Noncemented TKA was associated with a greater risk of periprosthetic joint infection throughout the study (90-day odds ratio [OR] 1.34, 1-year OR 1.27, 2-year OR 1.27, P < 0.05). Noncemented TKA was associated with a greater risk of periprosthetic fracture at 1 year and 2 years (1 year OR 2.19, 2 years OR 1.89, P < 0.05). No notable difference was observed in risk of aseptic loosening between the two groups.

DISCUSSION

Noncemented TKA is associated with a higher rate of periprosthetic joint infection and periprosthetic fracture. Additional studies are needed to compare long-term rates of aseptic loosening between noncemented and cemented TKA.

LEVEL OF EVIDENCE

Level III.

Redefining Indications for Modern Cementless Total Knee Arthroplasty: Clinical Outcomes and Survivorship in Patients >75 Years Old

BACKGROUND

Most studies on cementless total knee arthroplasty (TKA) have excluded patients >75 years due to concerns that older patients have poorer bone mineral density and osteogenic activity. This study compared the midterm outcomes and survivorship of cemented and cementless TKA of the same modern design performed in patients >75 years.

METHODS

We identified a consecutive series of 120 primary cementless TKA performed in patients >75 years. Each case was propensity score matched 1:3 with 360 cemented TKA of the same modern design based on age, sex, body mass index, Charlson Comorbidity Index, bilateral procedures, liner type, and year of surgery. Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR) and Short Form-12 (SF-12) were collected preoperatively, at 6 months and 2 years. Implant survivorship was recorded at mean 4.2 years (range, 2.0-7.9).

RESULTS

Mean age was 79.0 ± 3.4 years (range, 75-92) in the cemented cohort and 78.9 ± 3.5 (range, 75-91) in the cementless cohort (P = .769). There was no difference in final postoperative scores or improvement in scores at 2 years. The percentage of patients that met the minimal clinically important difference was also similar (KOOS-JR, 68.9% vs 69.2%, P = .955; SF-12 Physical, 71.7% vs 66.7%, P = .299). Seven-year survivorship free from aseptic revision was 99.4% for cemented knees and 100% for cementless knees (log-rank, P = .453).

CONCLUSION

Patients over 75 years undergoing cementless or cemented TKA of the same modern design had comparable outcomes and survivorship in the midterm. The theoretical risks of cementless fixation in this age group were not realized in this study.

Pulsatile Lavage During Cementation of Total Knee Arthroplasty - Is Fixation Impaired? A Cadaver Study

BACKGROUND/AIM

Increasing economic pressure in modern healthcare necessitates an increase in efficiency in total knee arthroplasty (TKA) while maintaining high-quality outcomes. Removal of debris using pulsatile lavage (PL) during cement polymerization may considerably reduce the operative duration. However, water can penetrate the interface, resulting in impaired implant fixation. The aim of the present study was to investigate the impact of early-onset PL during bone cement polymerization on implant fixation and operative duration.

MATERIALS AND METHODS

Cemented implantation of tibial trays was performed in 20 fresh-frozen human tibiae from 10 donors in a matched-pair study design in two groups: 1) PL during cement polymerization; and 2) PL after completion of the polymerization process. The cement penetration depth was analysed by computed tomography (CT), and the pull-out force was measured to evaluate primary implant fixation. The duration of the procedure was recorded for both groups.

RESULTS

Comparable pull-out forces were observed in the experimental (2,213 N) and control groups (2,350 N; p=0.68). The mean depth of cement penetration was similar in both groups. PL during cement polymerization could decrease the operative duration by 10 min.

CONCLUSION

The application of PL during cement polymerization could significantly reduce operative duration and had no adverse effect on the mechanical fixation of the tibial component.

Restricted kinematic alignment leads to uncompromised osseointegration of cementless total knee arthroplasty

PURPOSE

While kinematic alignment (KA) total knee arthroplasty (TKA) with cemented implants has been shown to provide equivalent or better results than mechanical alignment, its combination with cementless fixation has not yet been documented. The purpose of this study is to report (1) revision rate and causes, (2) clinical results based on patient report outcome measures (PROMs), and (3) radiological signs of implant dysfunction in patients with an uncemented TKA implanted with restricted KA (rKA), after a minimum follow-up of 2 years.

METHODS

This study included the first 100 consecutive uncemented cruciate retaining TKAs implanted between November 2015 and February 2018 by a single surgeon following rKA principles. At last follow-up, all adverse events and PROMs assessed by WOMAC, KOOS, and FJS scores were documented. Radiographic evaluation was performed to identify signs of implant loosening.

RESULTS

After a mean follow-up of 49 months (32, 60), no implant revision was performed for aseptic loosening. Three revisions were performed: one for malalignment, one for a deep infection, and one for instability. The mean WOMAC score was 20.1 (0-79, 21.3), the mean KOOS score was 71.5 (19.0-96.6, 19.8), and the mean FJS score was 65.9 (0-100, 29.6). No radiological evidence of implant aseptic loosening or osteolysis was identified.

CONCLUSION

This study shows that in 99% of our cases, rKA combined with the tested cementless TKA implant allowed for adequate secondary fixation and good functional outcomes in the short term. Favourable mid- to long-term implant survivorship is anticipated.

LEVEL OF EVIDENCE

III.

Evaluation and Management of a Painful Knee After Total Knee Arthroplasty

Pain after total knee arthroplasty (TKA) is not infrequent and may be indicative of a broad spectrum of prosthesis-related, intra-articular, or extra-articular pathologies. To diagnose and treat the underlying cause of a painful TKA, systematic evaluation of the patient is critical to ensure that they are managed appropriately and expeditiously. This evidence-based review presents current concepts regarding the pathophysiology, etiology, and diagnosis of painful TKA and our recommended approach for management. [Orthopedics. 2021;44(6):341-352.].

The Impact of the Largest National Joint Registry on Current Knee Replacement Longevity Estimates: An Analysis and Review of Knee Prosthesis Brand and Fixation Technique

BACKGROUND

The UK National Joint Registry is the single largest joint registry in the world enrolling 1.3 million patients and recently reaching 17 years of follow-up data. Current knee prosthesis longevity estimates are based off smaller sized international registries and the impact of fixation type on prosthesis survival remains unclear.

METHODS

We used the UK National Joint Registry 17th annual report to calculate pooled mean survival estimates of total knee replacements (TKRs), unicondylar knee replacements (UKRs), and patellofemoral knee replacements at 10 and 15 years based on both construct brand and fixation technique (cemented vs uncemented). Independent t-testing was performed for significance.

RESULTS

All-cause survivorship of TKRs at 10 and 15 years is 96.7% and 95.4%, respectively. For UKRs it is 89.8% and 80.7% and for patellofemoral knee replacements it is 81.6% and 76.5%. In regard to fixation technique, cemented and uncemented TKRs show similar survivorship at both time points. For UKRs uncemented constructs showed improved survivorship compared to cemented at 10 years (92.7% vs 88.2%, P < .001). This was greatest among those <65 years of age. In fact, all construct types regardless of fixation showed increased rate of revision in those <65 years vs those ≥65 years.

CONCLUSION

We provide more accurate estimations for knee prosthesis survival and highlight that younger patients, particularly those receiving UKRs, are prone to greater revision risks. This data also suggests that uncemented fixation may offer improved joint survival in these patients.

Effect of gap balancing and measured resection techniques on implant migration and contact kinematics of a cementless total knee arthroplasty

BACKGROUND

The purpose of this study was to compare implant migration and tibiofemoral contact kinematics of a cementless primary total knee arthroplasty (TKA) implanted using either a gap balancing (GB) or measured resection (MR) surgical technique.

METHODS

Thirty-nine patients underwent TKA via a GB (n = 19) or a MR (n = 20) surgical technique. Patients received an identical fixed-bearing, cruciate-retaining cementless implant. Patients underwent a baseline radiostereometric analysis (RSA) exam at two weeks post-operation, with follow-up visits at six weeks, three months, six months, and one year post-operation. Migration including maximum total point motion (MTPM) of the femoral and tibial components was calculated over time. At the one year visit patients also underwent a kinematic exam via RSA.

RESULTS

Mean MTPM of the tibial component at one year post-operation was not different (mean difference = 0.09 mm, p = 0.980) between the GB group (0.85 ± 0.37 mm) and the MR group (0.94 ± 0.41 mm). Femoral component MTPM at one year post-operation was also not different (mean difference = 0.27 mm, p = 0.463) between the GB group (0.62 ± 0.34 mm) and the MR group (0.89 ± 0.44 mm). Both groups displayed similar kinematic patterns.

CONCLUSIONS

There was no difference in implant migration and kinematics of a single-radius, cruciate retaining cementless TKA performed using a GB or MR surgical technique. The magnitude of migration suggests there is low risk of early loosening. The results provide support for using the cementless implant with either a GB or MR technique.

Acquired Idiopathic Stiffness After Contemporary Total Knee Arthroplasty: Incidence, Risk Factors, and Results Over 25 Years

BACKGROUND

Acquired idiopathic stiffness (AIS) remains a common failure mode of contemporary total knee arthroplasties (TKAs). The present study investigated the incidence of AIS and manipulation under anesthesia (MUA) at a single institution over time, determined outcomes of MUAs, and identified risk factors associated with AIS and MUA.

METHODS

We identified 9771 patients (12,735 knees) who underwent primary TKAs with cemented, modular metal-backed, posterior-stabilized implants from 2000 to 2016 using our institutional total joint registry. Mean age was 68 years, 57% were female, and mean body mass index was 33 kg/m². Demographic, surgical, and comorbidity data were investigated via univariate Cox proportional hazard models and fit to an adjusted multivariate model to access risk for AIS and MUA. Mean follow-up was 7 years.

RESULTS

During the study period, 456 knees (3.6%) developed AIS and 336 knees (2.6%) underwent MUA. Range of motion (ROM) increased a mean of 34° after the MUA; however, ROM for patients treated with MUA was inferior to patients without AIS at final follow-up (102° vs 116°, P < .0001). Significant risk factors included younger age (HR 2.3, P < .001), increased tourniquet time (HR 1.01, P < .001), general anesthesia (HR 1.3, P = .007), and diabetes (HR 1.5, P = .001).

CONCLUSION

Acquired idiopathic stiffness has continued to have an important adverse impact on the outcomes of a subset of patients undergoing primary TKAs. When utilized, MUA improved mean ROM by 34°, but patients treated with MUA still had decreased ROM compared to patients without AIS. Importantly, we identified several significant risk factors associated with AIS and subsequent MUA.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

'Skywalker' surgical robot for total knee arthroplasty: An experimental sawbone study

BACKGROUND

Currently, robot-assisted surgical systems are used to reduce the error range of total knee arthroplasty (TKA) osteotomy and component positioning.

METHODS

We used 20 sawbone models of the femur and 20 sawbone models of the tibia and fibula to evaluate the osteotomy effect of 'Skywalker' robot-assisted TKA.

RESULTS

The maximal movement of the cutting jig was less than 0.25 mm at each osteotomy plane. The mean and standard deviation values of the angle deviation between the planned osteotomy plane and the actual osteotomy plane at each osteotomy plane were not more than 1.03° and 0.55°, respectively. The mean and standard deviation values of absolute error of resection thickness at each osteotomy position were less than 0.78 and 0.71 mm, respectively.

CONCLUSIONS

The 'Skywalker' system has good osteotomy accuracy, can achieve the planned osteotomy well and is expected to assist surgeons in performing accurate TKA in clinical applications in future.

The Change in Posterior Tibial Slope After Cementless Unicondylar Knee Arthroplasty

BACKGROUND

The posterior tibial slope (PTS) is an important factor in patients undergoing unicondylar knee arthroplasty. It is an area subjected to high shear and compressive forces. Our objective is to investigate the changes taking place on the tibial slope of cementless unicondylar knee arthroplasties and define its relationship with functional scores.

METHODS

Patients undergoing a cementless unicondylar knee arthroplasty between January 2011 and July 2019 were selected. Exclusion criteria were lack of at least 1 year of follow up, loss to follow-up for any reason, and revision of a metallic component. Overall, 161 cases were included. Patients were analyzed using standard radiographs for changes in PTS, coronal positioning of the implant, and overhanging. Function was analyzed using Oxford Knee Score, Tegner Activity Scale, and Knee Society Score. Changes of the PTS were analyzed for statistical significance and for correlations with all the other variables.

RESULTS

All postoperative functional scores showed significant improvement (P < .05). Compared to the early postoperative values, increases of ≤5° were detected in 79% of all patients. The greater amount of slope change occurred during the first 6 months postoperatively. Statistical analysis revealed no significant relationship with functional scores of the knee, age, body mass index, overhanging, and coronal alignment of the tibial component.

CONCLUSION

This study showed that, with time, minimal changes take place in the PTS of cementless unicondylar knee arthroplasty. The change mostly takes place during the first 6 months. These changes do not affect functional scores.

Cementless Fixation in Primary Total Knee Arthroplasty: Historical Perspective to Contemporary Application

Cemented total knee arthroplasty (TKA) has been considered the benchmark, with excellent clinical outcomes and low rates of aseptic loosening at the long-term follow-up. However, alterations of the bone/cement interface leading to aseptic loosening, particularly in younger and obese patients, along with increased life expectancy have led to a renewed interest in noncemented TKA fixation. Certain early noncemented designs exhibited higher rates of subsidence and component failure. Improvements in designs, materials, and surgical technique offer promise for improved results with contemporary noncemented TKA applications. In an increasing cost-conscious healthcare environment, implant cost is important to consider because press-fit prostheses are generally more expensive. However, this cost may be offset by shorter surgical times, cement costs, and the potential for osseous integration. Technological advances have improved the manufacturing of porous metals, with reported excellent midterm survivorship. Future prospective, randomized trials, and registry data are needed to delineate differences between cemented and noncemented fixation, survivorship, and patient-reported outcomes, especially in young, functionally active, and/or obese populations.

A comprehensive comparison between cementless and cemented fixation in the total knee arthroplasty: an updated systematic review and meta-analysis

BACKGROUND

Whether the cement should be used in the total knee arthroplasty (TKA) was still in controversy. This meta-analysis was performed to compare the efficacy of two kinds of fixation.

METHODS

Randomized controlled trials (RCTs), prospective/retrospective observational studies from PubMed (on 2019 September), EMBASE (on 2019 September), and the Cochrane Central Register of Controlled Trials (CENTRAL) and Web of Science (on 2019 September) were searched. Only studies followed more than 2 years was included for the review. The PRISMA guidelines and Cochrane Handbook were adopted to assess the quality of the results reported in included studies to ensure that the results of our meta-analysis were reliable and veritable. The continuous and dichotomous outcomes were collected in a standard form, and the data were analyzed by Review Manager 5.3 software. Finally, the results were presented in the Forest plots.

RESULTS

Twenty-six studies involving 2369 patients in cementless TKA and 2654 patients in cemented TKA were included. The rate of revision was not significantly different in two groups (p = 0.55). More than eight reasons caused revision were found in our study, the aseptic loosing was the most common, followed by the periprosthetic joint infection (PJI), neither was significantly different (p = 0.88 and 0.45, respectively). While significantly better long-term functional recovery was found in cementless TKA in terms of Knee Society Function Score (p = 0.004) and manipulation under anesthesia (p = 0.007).

CONCLUSION

Cementless fixation did not decrease the rate of revision after the total knee arthroplasty compared with the cemented fixation, while the long-term functional recovery was significantly better in the cementless group.