The Case for Cementless Total Knee Arthroplasty.

The demographics of total knee arthroplasty (TKA) patients are changing. Individuals are more active, younger, and more obese. These changing demographics and a higher demand for longevity creates a new challenge for reliable and long-term implant fixation. Historically, cemented fixation has remained the gold standard, as cementless design and techniques from the 1980s and 1990s did not obtain long-term positive outcomes due to a failure of ingrowth onto the implants. Advances in the modern-day cementless TKA designs appear to have overcome their initial challenges, indicating the dependence of cementless TKA on implant design. However, there remains the perception that cementless total knee arthroplasty are inferior to cemented TKA. This review discusses the longer-term survivorship data for recent systems, which has shown the potential advantages of cementless fixation.

Newer Generation of Cementless Total Knee Arthroplasty: A Systematic Review.

INTRODUCTION: Although the use of cementless implants in total knee arthroplasty (TKA) has increased in recent years, there is still ongoing debate regarding the optimal method of fixation. The purpose of this review was to evaluate the evidence regarding cementless versus cemented total knee arthroplasty (TKA) with regard to: (1) all-cause survivorship and aseptic survivorship; and (2) patient-reported outcome measures (PROMs) of newer generation TKAs. MATERIALS AND METHODS: A systematic review of all reports on cementless TKA published from January 2010 to February 2019 was performed. A total of 221 articles were evaluated and 39 studies met inclusion criteria for final analysis. Metrics evaluated included all-cause survivorship, aseptic survivorship, and Knee Society Scores (KSS). RESULTS: Modern cementless TKA provides excellent survivorship and patient-reported outcomes as compared to cemented designs. CONCLUSIONS: Recent studies have demonstrated that newer generation cementless TKAs provide similar functional outcomes and survivorship as compared to cemented TKA. However, additional prospective, randomized trials with long-term follow up are necessary to further compare the outcomes of cementless versus cemented TKA.

Is Operative Time a Predictor for Post-Operative Infection in Primary Total Knee Arthroplasty?

BACKGROUND: The purpose of this study is to identify factors affecting operative times and to evaluate the associations of operative times with prosthetic joint infections (PJIs) and surgical site infections (SSIs) in primary total knee arthroplasty. METHODS: A total of 11,840 primary total knee arthroplasties with a mean 2-year post-operative follow-up were studied. Operative times were analyzed both as categorical and continuous variables. Associations with PJIs and SSIs were evaluated with univariate and multivariate analyses to adjust for gender, age, body mass index, Charlson Comorbidity Index, year of surgery, antibiotic cement use, and hospital/surgeon volume. RESULTS: The longest cases (>121 minutes) were associated with patients who were younger (P < .001) and had a higher body mass index (P < .001). PJI rates were higher in cases >121 minutes (1.4%) compared to those <85 minutes (0.3%, P < .001). SSI rates were also highest (3.8%) in cases >121 minutes (P < .001). Cases complicated by PJIs (135 ± 47 minutes) had longer mean operative times compared to non-infected cases (105 ± 32 minutes, P < .001). Patients with subsequent SSIs also had longer mean operative times (P < .001). Multivariate analyses revealed an 18% increased risk for PJIs and an 11% increased risk for SSIs for every 15-minute increase in operative time. CONCLUSION: Identifying risk factors for infection that are as easily measurable and modifiable as procedure duration can aid in risk-stratifying post-operative surveillance. This study demonstrated that longer operative times were an independent predisposing factor for both PJIs and SSIs even after accounting for patient and procedure-related factors.

Effect of Antibiotic-Impregnated Bone Cement in Primary Total Knee Arthroplasty.

BACKGROUND: The purpose of this study is to evaluate the effect of commercially available antibiotic-impregnated bone cement (AIBC) on (1) prosthetic joint infections (PJIs) and (2) surgical site infections (SSIs) after primary total knee arthroplasty (TKA). METHODS: A review of primary TKAs between 2014 and 2017 from an institutional database was conducted. This identified 12,541 cases which were separated into AIBC (n = 4337) and non-AIBC (8,164) cohorts. Medical records were reviewed for PJIs and SSIs (mean 2-year postoperative period). Infection rates between the cohorts were compared with univariate analyses followed by subanalysis of high risk patients (defined as having 2 or more of the following characteristics: >65 years, body mass index >40, or Charlson Comorbidity Index score >3). To control for confounders, multivariate analyses were performed with regression models adjusted for age, gender, body mass index, comorbidities, year, operative times, and lengths of stay. RESULTS: On univariate analysis, PJI rates were higher in the AIBC cohort (1.0%) compared to the non-AIBC cohort (0.5%, P < .001). Subanalysis of the high risk patients also showed that PJI rates were higher in the AIBC cohort (1.9% vs 0.6%, P < .01). After adjusting for potential confounders, no significant associations between PJIs and AIBC use were found (odds ratio 1.4, 95% confidence interval 0.9-2.3, P = .133). Similarly, no significant differences in SSI rates were observed between the AIBC (2.9%) and non-AIBC cohorts (2.4%, P = .060) and no significant associations between SSIs and AIBC were found with multivariate analysis (odds ratio 1.0, 95% confidence interval CI 0.8-1.3, P = .948). CONCLUSION: This study found that there was no clinically or statistically significant decrease in infection rates with AIBC in primary TKAs.

Evidence-Based Management of Trunnionosis in Metal-on-Polyethylene Total Hip Arthroplasty: A Systematic Review.

Multiple recent reports have indicated a rising awareness of trunnionosis-related implant failures, accounting for up to 3% of all total hip arthroplasty revisions. Moreover, aseptic loosening and osteolysis from local release of metal debris can be the presenting manifestations, and thus the true incidence of trunnionosis is thought to be underreported. Furthermore, the relatively unclear and multifactorial pathogenesis and the widely variable clinical presentations pose a diagnostic challenge. A consensus regarding the ideal intervention and its timing is also lacking. Because of the relative paucity of reports regarding the diagnosis and management of trunnionosis, we conducted this evidence-based review to evaluate the (1) incidence, (2) pathogenesis, (3) diagnosis, and (4) treatment of trunnionosis in metal-on-polyethylene total hip arthroplasty. We then propose an algorithm for the diagnostic work-up and management of this condition.

Linear Wear Rates of a Highly Cross-Linked Polyethylene Hip Liner.

INTRODUCTION: To help limit wear, newer polyethylene liners, such as the highly cross-linked polyethylene (HXLPE) liners, have been developed. These newer liners undergo an alternating irradiation process, resulting in a stronger, longer-lasting liner. The purpose of this study was to analyze the wear rates of patients who underwent THA and received a newer generation HXLPE acetabular insert. Specifically, we compared: 1) linear vector wear amount and 2) linear vector wear rates in patients as an overall cohort and by gender. We also assessed patient satisfaction outcomes comparing preoperative Harris Hip Scores (HHS) to seven-week, one-year, and three-year HHS scores. MATERIALS AND METHODS: A total of 23 patients who underwent total hip arthroplasty (THA) with direct superior approach by a fellowship-trained orthopaedic surgeon at a private practice institution were analyzed after receiving institutional review board approval. Patients had a minimum two-year follow up, with the mean follow up being four years (range, three to five years). All patients received a 36-mm ceramic femoral head with an HXLPE liner. 2D radiographic polyethylene wear analysis was performed using the Martell Hip Analysis Suite (HAS; University of Chicago, Illinois), which has been previously validated in the literature. Outcomes were assessed using Harris Hip Scores. RESULTS: A five-year linear wear rate of 0.073 mm/year (range, 0 to 0.160 mm/year) and an overall mean linear wear rate of 0.096 mm/year (range, 0 to 0.277 mm/year) were found. No significant differences in wear were seen between genders. Additionally, patients reported significantly better results at seven-weeks (83 points [range, 59 to 100 points]) and one-year (94 points [range, 85 to 100 points]) than preoperative (52 points [range, 34 to 73 points]) HSS scores (p<0.05). No patients underwent revision THA. CONCLUSION: The results from this study highlight the benefits of using an HXLPE polyethylene liner in THA patients and further validates previously reported wear rates of HXLPE liners. After an early "wear in" period during the first year, the wear rates steadily decreased over time. This liner showed excellent early outcomes as no patients underwent revision THA. Furthermore, even as early as seven postoperative weeks, patients reported significantly better HHS scores. Future studies should track the same patient cohort over time to help develop a wear-rate prediction model.

Cementless Tritanium Baseplate Total Knee Arthroplasty: Survivorship and Outcomes at 5-Year Minimum Follow-Up.

BACKGROUND: Newer generation cementless total knee arthroplasty (TKA) designs have provided stronger osteointegration between the implant and bone. Despite excellent survivorship and outcomes with cemented TKAs, areas of concern within the bone-cement interface remain a concern and necessitate studies on alternative constructs. This study assesses: (1) implant survivorship; (2) clinical outcomes; and (3) complications with radiographic outcomes at a 5-year minimum follow-up of cementless highly porous titanium-coated baseplates in TKAs. METHODS: Part of this study has been reported. We retrospectively reviewed a prospectively collected database at a single high-volume institution between July 1, 2013 and June 30, 2014 for patients who underwent a primary TKA using cementless highly porous titanium-coated baseplate implants. Patients were evaluated clinically at postoperative follow-up visits at a minimum of 5 years. To calculate the survivorship, Kaplan-Meier analysis was performed to determine all-cause, aseptic, and septic implant survivorship at each final follow-up for all patients. RESULTS: A total of 228 TKAs were performed and followed for a minimum of 5 years (range, 5-6 years). As of the latest follow-up, one case of septic loosening of the patellar button and one case of patellar dislodgment secondary to physical manipulation were recorded and revised. Overall, the cohort displayed implant survivorship of 99.5% at 5-year minimum follow-up. Improvements were seen in both Knee Society pain and function scores and were 37 points (range, 17-60 points) and 28 points (range, 15-47 points), respectively. The mean improvement in flexion was 17.8 (range, -20 to 40 degrees) and mean improvement in extension was -5.5 (range, -30 to 5 degrees). DISCUSSION: Cementless TKAs serve as strong alternative choice to cemented TKAs. Although cemented fixation is commonly known as the gold standard, results of this study confirm the findings of previous investigations on the survivorship of cementless TKA implants. Therefore, patients who undergo primary TKA with a cementless tritanium baseplate can expect excellent clinical outcomes at a 5-year minimum follow-up.

Survivorship and Functional Outcomes of Cementless versus Cemented Total Knee Arthroplasty: A Meta-Analysis.

The purpose of this meta-analysis was to assess the evidence supporting the use of cementless versus cemented total knee arthroplasties (TKAs). Specifically, we evaluated (1) all-cause survivorship, (2) aseptic survivorship, and (3) functional outcomes (Knee Society Scores [KSS], Oxford Knee Scores, Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC] scores, and ranges of motion [ROMs]). A literature search was performed for studies that evaluated cementless versus cemented TKAs published between 2000 and 2017. Selected studies included three randomized controlled trials, three retrospective observational studies, and one prospective observational study that met the following criteria: (1) primary TKAs, (2) compared cementless and cemented TKAs, (3) implant survivorship that described the causes of failure, and (4) at least one functional outcome. To compare the two cohorts, pooled odds ratios (OR) and 95% confidence intervals (95% CI) were used to calculate tibial and femoral implant survivorship, and pooled mean differences (MD) and 95% CI calculated the functional scores and ROMs. Based on pooled data from the few number of studies, cementless TKAs had a better all-cause survivorship (OR = 0.37; 95% CI, 0.15-0.92) and tended to have a better aseptic survivorship (OR = 0.44; 95% CI, 0.17-1.14). However, this is likely due to the 83.3% weight of the single cementless study potentially influencing the analysis. There were no differences in terms of KSS knee (MD = 1.03; 95% CI, -1.13-3.20) or function scores (MD = 5.36; 95% CI, -3.75-14.51), Oxford knee scores (MD = 0.36; 95% CI, -3.84-4.56), or WOMAC scores (MD = 0.62; 95% CI, -0.87-2.11). Moreover, there was no difference in ROMs (MD = 1.47; 95% CI, -0.11-3.05). Cementless TKA had a better all-cause survivorship when compared with cemented fixation, and similar functional outcomes were demonstrated. However, these findings are based on only a few number of studies (n = 7). Therefore, additional prospective, randomized control trials need to be performed to best compare cementless versus cemented outcomes.

Postoperative Infection in Cementless and Cemented Total Knee Arthroplasty: A Propensity Score Matched Analysis.

The ongoing debate on fixation in total knee arthroplasty (TKA) has become increasingly relevant with its increased use in a younger patient population and the advent of novel cementless prostheses. Recent literature suggests modern cementless implants are comparable to their cemented counterparts in terms of survivorship and functional outcomes. What has not been well-assessed is whether the two modalities differ with respect to infection rates which was the purpose of this study. Specifically, a propensity score matched study population was used to compare: (1) overall infection; (2) prosthetic joint infection (PJI); and (3) surgical site infection (SSI) rates between cementless and cemented TKAs. Using a large institutional database, 3,180 consecutive primary TKAs were identified. Cementless and cemented TKA patients were propensity score matched by age (p = 0.069), sex (p = 0.395), body mass index (BMI; p = 0.308), and Charlson's comorbidity index (CCI) score (p = 0.616) in a 1:1 ratio. Univariate analysis was performed to compare 2-year overall infection rates. Infections were further analyzed separately as PJIs (deep joint infections requiring surgery) and SSIs (skin/superficial wound infections). Multivariate logistic regression was performed to evaluate infection incidences after adjusting for procedure-related factors (i.e., operative time, hospital volume, and surgeon volume). There were no significant differences between the matched cohorts in terms of overall infection rates (3.8 vs. 2.3%, p = 0.722), as well as when PJI (p = 1.000) and SSI (p = 1.000) rates were analyzed separately. Multivariate analysis revealed no significant differences in overall postoperative infection rates (p = 0.285), PJI rates (p = 0.446), or SSI rates (p = 0.453) even after adjusting for procedure-related factors. There is increasing literature investigating various outcomes demonstrating the comparable efficacies of cementless versus cemented TKAs. To the best of the author's knowledge, this was the first matched case-control study to directly compare their post-operative infection rates. The findings from this study show that post-operative infection rates were similar between fixation modalities even after accounting for a range of patient- and procedure-related factors.

Cementless Total Knee Arthroplasty: A Comprehensive Review of the Literature.

This review evaluated (1) original and newer cementless implants; (2) outcomes of newer designs; (3) risks and benefits; and (4) newer cementless vs cemented total knee arthroplasties. A search for all reports on cementless total knee arthroplasties published from January 2010 to April 2017 was performed, and 31 studies were included for final analysis. Newer cementless total knee arthroplasty designs have shown excellent survivorship, functional outcomes, and satisfaction rates in both young and elderly populations. Compared with cement fixation, there may be potential benefits with the newer cementless implants. However, these findings need to be further substantiated with additional studies reporting longer-term results. [Orthopedics. 2018; 41(5):263-273.].

Outcomes of Cementless Total Knee Arthroplasty in Patients With Rheumatoid Arthritis.

The objective of this study was to evaluate implant survivorship, clinical outcomes, postoperative complications, and radiographic outcomes of cementless total knee arthroplasty (TKA) in patients who have rheumatoid arthritis (RA). Patients who underwent a primary cementless posterior-stabilized TKA and who had RA were reviewed. A total of 126 TKAs in 122 patients who had a mean follow-up of 4 years were analyzed. Implant survivorship was calculated. Postoperative clinical and radiographic follow-up was performed at approximately 6 weeks and 3 months and then annually. Changes in range of motion and Knee Society scores were noted. Radiographic evaluation was conducted as part of the follow-up process. Implant survivorship was 99.2%, with 1 aseptic failure. At final follow-up, mean extension and flexion were 2° (range, 0°-10°) and 124° (range, 95°-140°), respectively. Mean Knee Society pain and function scores were 92 points (range, 80-100 points) and 84 points (range, 70-90 points), respectively. There were no surgical complications. No progressive radiolucencies, loosening, or subsidence were noted except from the single aseptic failure reported. This study reports excellent survivorship and clinical and radiographic outcomes of cementless TKAs in RA patients. Although the decision regarding whether to use cemented or cementless TKAs in these patients should be based on surgeon experience and patient characteristics, the recent advances in implant fixation of cementless TKAs indicate no salient contraindications for RA patients. [Orthopedics. 2018; 41(2):103-106.].