Cemented Versus Cementless Total Knee Arthroplasty in Obese Patients With Body Mass Index ≥35 kg/m2: A Contemporary Analysis of 812 Patients

Cemented vs. uncemented total knee arthroplasty in obese patients: A systematic review of implant survival, complications, and clinical outcomes

Introduction

Obesity is a primary global health concern that negatively affects the outcomes of total knee arthroplasty (TKA). To mitigate complications, both cemented and uncemented fixation techniques have been considered. However, there remains no consensus in the literature regarding the optimal fixation method for obese patients despite the renewed interest in uncemented fixation. This systematic review aims to compare the survival rates, causes of failure, and patient-reported outcome measures (PROMs) between cemented TKA (cTKA) and uncemented TKA (uTKA) in the obese population.

Materials and methods

A comprehensive literature search was conducted according to PRISMA guidelines across five databases-PubMed, Scopus, Embase, Medline, and Cochrane-focusing on studies directly comparing cTKA and uTKA in obese patients. The ROBINS-I tool was used to assess the risk of bias, while the PRISMA flow diagram guided the study selection process based on predefined inclusion and exclusion criteria. This systematic review was registered on PROSPERO.

Results

Four retrospective studies encompassing 1622 patients met the inclusion criteria and were included in the final qualitative analysis. Among these, 50 % of patients underwent uTKA, with three studies exclusively analyzing individuals with at least class II obesity (BMI ≥35 kg/m2). All four studies reported higher rates of aseptic loosening in the cemented fixation group. However, only two studies demonstrated a statistically significant improvement in implant survival, reduced aseptic loosening, and lower revision rates with cementless fixation in the short-to mid-term follow-up. Regarding clinical outcomes, only one study reported a significant improvement in Knee Society Score (KSS) function, range of motion (ROM), and pain scores in the cementless group compared to the cemented group, particularly in the subgroup analysis of posterior-stabilized constrained TKA.

Conclusion

This systematic review suggests that in obese patients, particularly those with BMI ≥35 kg/m2, cementless fixation offers comparable or superior implant survival rates and lower rates of aseptic loosening compared to cemented fixation in the short-to mid-term follow-up. Furthermore, cementless fixation may provide similar or enhanced clinical outcomes in this high-risk and growing patient population.

Cemented and Cementless Robotic-Assisted versus Manual Total Knee Arthroplasty Outcomes: A Single Center Michigan Arthroplasty Registry Collaborative Quality Initiative-Based Study

BACKGROUND

The purpose of our study was to determine whether a difference existed between cemented and cementless robotic-assisted total knee arthroplasty (RA-TKA) and manual TKA with regard to revision rates and 90-day outcomes. We hypothesized these techniques would have similar results.

METHODS

A single center's data from the Michigan Arthroplasty Registry Collaborative Quality Initiative were queried for all primary TKAs from January 2012 to July 2023. The RA-TKA and manual cohorts were compared for revisions and 90-day complications, including emergency department (ED) visits, readmissions, and returns to the operating room Chi-square and Fisher's exact tests were used for categorical data, and t-tests for continuous data. Of the 7,417 cemented TKAs (mean age 67 ± 9.6 years, 70% women), 273 were RA-TKA and 7,144 were manual. Of the 2,407 cementless TKAs (mean age 65 ± 8.6 years, 53% women), 730 were RA-TKA and 1,677 were manual.

RESULTS

Cemented RA-TKA had more periprosthetic joint infection revisions, more 90-day ED visits, and readmissions for wound complications compared to cemented manual TKA. Cementless RA-TKA had more 90-day readmissions for wound complications, while manual TKA had more 90-day ED visits for postoperative pain. Cemented and cementless RA-TKA had longer surgical time, shorter length of stay, and shorter time to revision. There were 283 revisions performed on cemented manual TKA (nine RA-TKAs, 3.2%, 274 manual, 3.8%, (P = 0.87)). There were 56 revisions performed on cementless knees (13 RA-TKAs, 1.7%, 43 manual 2.5% (P = 0.303)). Cumulative percent revision at 5 years was 3.9% for cemented RA-TKA, 3.5% for cemented manual TKA, 1.8% for cementless RA-TKA, and 2.8% for cementless manual TKA.

CONCLUSIONS

Both RA-TKA and manual TKA have similar revision rates, while RA-TKA had more wound complications. Cementless RA-TKA may be beneficial in reducing postoperative pain.

Cementless unicompartmental knee arthroplasty is safe and effective at a minimum follow-up of 4.2 years: A systematic review

Purpose

Cemented unicompartmental knee arthroplasty (UKA) is a widely used procedure in the treatment of anteromedial and lateral knee osteoarthritis. However, several advantages are reported for cementless UKA, such as improved osseointegration, reduced cement-related costs and complications. The aim of this study was to analyse clinical outcomes, survival, complications, failures and revision rate of cementless UKA.

Methods

A systematic review was performed on 31 May 2024, on PubMed, Cochrane Library and Scopus. We included randomised clinical trials and prospective and retrospective studies reporting clinical outcomes, implant survival, complications, failures and revision rates of cementless UKA. The following data were extracted: study design, type of implant, number of patients and knees, follow-up, age, sex, pre-operative and post-operative clinical outcomes, reoperations and revisions with causes of failure and overall survival.

Results

Fifteen studies were included, involving 3475 patients and 3641 UKA (2568 cementless UKA and 854 cemented UKA). The mean patients' age was 66 years. The mean follow-up was 6.5 years. The Oxford Knee Score improved from 17.8 preoperatively to 40.3 post-operatively in cementless UKA. Knee Society Score improved from 118.2 preoperatively to 168.6 post-operatively in cementless UKA. The reoperation rate was 3.85% for cementless UKA and 9% for cemented UKA. The most common causes of revision were osteoarthritis progression (1.4%), aseptic loosening (0.8%), bearing dislocation and unexplained pain (0.7%). The overall survival of cementless UKA was 96.2% and 93.6% at 5 and 10 years, respectively.

Conclusion

Cementless UKA is a viable alternative to cemented UKAs with a low failure rate, without a lower clinical benefit at a minimum follow-up of 4.2 years.

Level of Evidence

Level III, systematic review of studies.

Short-Term Outcomes of Noncemented Total Knee Arthroplasty in Patients With Morbid Obesity

INTRODUCTION

Noncemented primary total knee arthroplasty (TKA) compromises over 14% of all primary TKA procedures reported in the American Joint Replacement Registry. While studies have indicated similar outcomes for cemented and noncemented TKA in obese individuals, the efficacy and safety of noncemented TKA in morbidly obese patients (body mass index [BMI] ≥ 40 kg/m2) remain unexplored. This study compares short-term postoperative outcomes and complications between noncemented and cemented TKA in morbidly obese patients.

METHODS

A retrospective review of 605 cases of patients with a BMI of at least 40 kg/m2 (22.5% of 2,691 total cases at a single tertiary center) who underwent TKA was conducted. All patients had a minimum follow-up of 1 year. Data collected included age, BMI, sex, race, ethnicity, American Society of Anesthesiologists status, and the Charlson Comorbidity Index. Postoperative complications were tracked, including 90-day readmission, 1-year mortality, 1-year revision surgery, wound complications, fractures, and infections. Categorical variables were analyzed with chi-square tests and continuous variables with t-tests.

RESULTS

Of the included patients with a BMI ≥ 40 kg/m2, 40 (6.6%) received noncemented TKA. The noncemented TKA group had a lower mean BMI (43.3 ± 3.1 vs. 45.0 ± 4.4; P = 0.012) and a higher proportion of male patients compared with the cemented group (n = 17 [42.5%] vs. n = 143 [25.3%]; P = 0.028). Surgical time was shorter for noncemented TKA (97 ± 27 minutes) than for cemented TKA (118.0 ± 39.4 minutes; P = 0.001). No significant differences were found in length of stay and postoperative complications, including 90-day readmission, 1-year mortality, revision surgery rates, wound complications, fractures, and infections.

CONCLUSION

The findings of the study suggest that noncemented TKA may be a feasible, safe alternative and not inferior to the standard cemented TKA in patients with morbid obesity with the benefit of decreasing surgical time.

10-Year Follow-Up for a New Three-Dimensional Printed Cementless Total Knee Arthroplasty

BACKGROUND

Cementless total knee arthroplasty (TKA) offers the potential for durable fixation through biological integration compared to cemented TKA, where fixation is achieved through mechanical interdigitation of the cement. To our knowledge, no 10-year results are available for newer cementless TKA designs that have incorporated additive manufacturing (three-dimensional [3D] printing). The purpose of this study was to present 10-year survivorship and clinical/radiographic outcomes of a newer cementless TKA design.

METHODS

This is a single institution registry review of prospectively obtained data from a total of 113 cementless TKAs at a 10-year follow-up. Outcomes were determined by comparing pre-and post-operative Knee Injury and Osteoarthritis Outcome Scores for Joint Replacement scores and pre- and post-operative 12-item Veterans RAND/Short Form Health Survey. Aseptic loosening as well as revision for any reason were the end points used to determine survivorship at 10 years.

RESULTS

The overall survivorship was 96.5% at 10 years, and survivorship for aseptic loosening as the end point was 98.2%, with a 99.1% survivorship of the 3D printed tibial component. There were four revisions performed (all within 2 years postoperatively) for an overall revision rate of 3.5%: two infections (1.7%) and two loosenings (1.7%). No new loosening was identified after 2 years of follow-up. At long-term 10-year follow-up, the mean Knee Injury and Osteoarthritis Outcome Scores for Joint Replacement score improved from 38.2 preoperatively to 72.8 postoperatively (P = 0.0001), the mean 12-item Veterans RAND/Short Form Health Survey scores improved from physical health-29.8 preoperatively to 40.6 postoperatively (P = 0.0001), and the mental health scores improved from 37.02 preoperatively to 54.3 postoperatively (P = 0.0001).

CONCLUSIONS

This 3D printed cementless total knee system shows exceptional survivorship at a 10-year follow-up. The design of this implant and the ability to obtain cementless fixation offer promise for excellent long-term durability.

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.

Mid-term radiographic evaluation of a monoblock trabecular metal tibia following total knee arthroplasty in obese and morbidly obese patients

BACKGROUND

Indications for primary total knee arthroplasty (TKA) have become more inclusive of morbidly obese patients, however, higher rates of complications and lower implant survival have also been reported in this population. The purpose of this study was to investigate the mid-term survival, clinical, and radiographic outcomes of a cementless trabecular metal monoblock tibial component in severely obese patients.

METHODS

This was a retrospective study of class II and III obese (BMI > 35) patients who received a cementless primary TKA. Standing radiographs were assessed for the presence of progressive tibial radiolucent lines (RLL), and clinical measures were assessed at least 2 years post-operative via the Oxford Knee Score (OKS), UCLA Activity and Satisfaction Score, and the Euro-QoL 5-dimension (EQ-5D-5L) index and visual analogue scale (EQ-VAS) health status.

RESULTS

Patients (n = 176) were 61.2 ± 8.3 years of age, BMI 44.9 ± 6.5 kg/m2, and were predominantly female (n = 118, 66.7%). Mean follow-up was 59.2 ± 17.1 months. There were two total revisions at 6- and 57-months post-operative, respectively, and the 5-year survival estimate was 98.3% (95% confidence interval: 93.0%, 99.6%). Patient satisfaction was 93.9% and the post-operative OKS, EQ-5D-5L index, and EQ-VAS were 40.2 ± 7.9, 0.856 ± 0.205, and 73.6 ± 14.7, respectively. No cases of radiolucent lines were detected.

CONCLUSIONS

At 6 years this cementless monoblock tibial component demonstrated excellent survival without radiographic indications of aseptic loosening in a population of severely obese patients.

Cementless Total Knee Arthroplasty: A Resurgence-Who, When, Where, and How?

BACKGROUND

Total knee arthroplasty (TKA) is one of the most common procedures in orthopaedics, but there is still debate over the optimal fixation method for long-term durability: cement versus cementless bone ingrowth. Recent improvements in implant materials and technology have offered the possibility of cementless TKA to change clinical practice with durable, stable biological fixation of the implants, improved operative efficiency, and optimal long-term results, particularly in younger and more active patients.

METHODS

This symposium evaluated the history of cementless TKA, the recent resurgence, and appropriate patient selection, as well as the historical and modern-generation outcomes of each implant (tibia, femur, and patella). Additionally, surgical technique pearls to assist in reliable, reproducible outcomes were detailed.

RESULTS

Historically, cemented fixation has been the gold standard for TKA. However, cementless fixation is increasing in prevalence in the United States and globally, with equivalent or improved results demonstrated in appropriately selected patients.

CONCLUSIONS

Cementless TKA provides durable biologic fixation and successful long-term results with improved operating room efficiency. Cementless TKA may be broadly utilized in appropriately selected patients, with intraoperative care taken to perform meticulous bone cuts to promote appropriate bony contact and biologic fixation.

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.

Short-Term (6 Months or Less) Pain in Cemented versus Cementless Total Knee Arthroplasty: A Systematic Review and Meta-Analysis

BACKGROUND

Cementless total knee arthroplasty (TKA) has increased in popularity to potentially improve survivorship. Radiostereometric studies demonstrate increased component migration during the first 3 to 6 months in cementless constructs, generating concern for increased postoperative pain during early osseointegration. The purpose of this study was to evaluate short-term (≤ 6 months) pain and function in cemented versus cementless TKA. We hypothesized that cementless TKA patients report increased pain during the short-term (≤ 6 months) postoperative period.

METHODS

The MEDLINE, EMBASE, CINAHL, and Cochrane Libraries were searched for studies evaluating short-term (≤ 6 months) outcomes of cemented versus cementless primary TKA. Studies involving hybrid fixation were excluded. A meta-analysis was performed using standardized mean difference for primary outcomes (early postoperative pain) and weighted mean difference (WMD) for secondary outcomes (early postoperative function).

RESULTS

There were eleven studies included. There was no significant difference in acute postoperative pain between cemented and cementless TKA within 6 months of index TKA (standardized mean difference 0.08 in favor of cemented TKA; P = .10). Early postoperative forgotten joint scores (WMD 0.81; P = .81) and knee injury and osteoarthritis outcome scores for joint replacement (WMD 0.80 in favor of cemented TKA; P = .14) were also similar between groups.

CONCLUSIONS

There is no difference in short-term (≤ 6 months) pain or early function between patients receiving cemented and cementless TKA. This suggests that surgeons may utilize cementless TKA without fear of increased pain due to micromotion within 6 months of index arthroplasty. However, additional studies with uniform assessment methods are needed to further inform differences in short-term pain and early functional outcomes between cemented and cementless 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.

Cemented vs Cementless Robotic-Assisted Total Knee Arthroplasty Yield Similar Short-Term Clinical Outcomes

Background

In primary total knee arthroplasty (TKA), there is ongoing controversy about optimal fixation (cemented vs cementless). Cemented TKA remains the gold standard, with the largest body of long-term evidence available to support it. However, cementless TKA implants are gaining popularity due to potential biomechanical advantages and a growing body of literature supporting survivorship. Due to paucity of literature investigating fixation methods in robotic-assisted TKA (Ra-TKA), we aim to compare clinical outcomes of cementless Ra-TKA with those of cemented Ra-TKA.

Methods

This is a retrospective cohort study of patients who underwent Ra-TKA by 19 surgeons comparing results of cases using cementless vs cemented fixation. We observed short-term complications, emergency room visits, and readmissions. We collected patient-reported outcomes measurement information system and knee injury and osteoarthritis outcome scores preoperatively and 12 weeks after surgery.

Results

A total of 582 TKA cases were included: 335 cementless and 247 cemented. The patients in the cementless group were younger and had a higher body mass index. The cemented group had a higher rate of return to the operating room, with manipulation under anesthesia for stiffness being the most common indication in both groups. There were no statistically significant differences in 30-day readmissions, 90-day emergency room visits, or patient-reported outcomes.

Conclusions

Our retrospective study demonstrated higher return to operating room in the cemented group vs the cementless group. We reported no differences in any other short-term outcomes between the cementless and cemented Ra-TKA. Our data support efficacy and safety of cementless Ra-TKA at 3-month follow-up.

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.

Comparison of bilateral cementless total knee arthroplasty results between patients in different BMI groups

INTRODUCTION

The aim of this study was to compare the results of cementless bilateral total knee arthroplasty (TKA) between individuals in different obesity groups.

MATERIALS AND METHODS

This was a retrospective cohort study. Patients with a body mass index (BMI) greater than 25 who underwent bilateral TKA for gonarthrosis between 2014 and 2020 and completed a minimum follow-up of 24 months were included. Age, sex, height, weight, BMI, operation time, length of stay, patient satisfaction, knee scores and complications were compared. Patients with missing data, who were followed for less than 24 months or had postoperative fractures around the knee were excluded.

RESULTS

There was a significant difference between the groups in terms of operation time (Class III > overweight > Class II > Class I p < 0.001). There was a significant difference in complications between the groups (Class III > Class I > Class II > overweight p = 0.010). According to our pairwise comparison, complications were more common in the class III group than in the overweight group. Knee score (KS) and function score (FS) increased significantly after surgery in all groups (p < 0.001), with no difference in FS (p = 0.448). Knee score changes were greater in the overweight and class I groups (p < 0.001). There was a significant interaction between both KS and FS and person satisfaction (p < 0.001).

CONCLUSION

Cementless TKA improved KS and FS in all obesity groups, yielded high patient satisfaction. Although the incidence of complications was higher in the morbidly obese patients than in the overweight patients, the difference was not significant. Patients with morbid obesity should be informed about related risks before planning cementless TKA.

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.

Go Big or Go Home: Obesity and Total Joint Arthroplasty

Obesity is highly prevalent, and it is expected to grow considerably in the United States. The association between obesity and an increased risk of complications following total joint arthroplasty (TJA) is widely accepted. Many believe that patients with body mass index (BMI) >40 have complications rates that may outweigh the benefits of surgery and should consider delaying it. However, the current literature on obesity and outcomes following TJA is observational, very heterogeneous, and full of confounding variables. BMI in isolation has several flaws and recent literature suggests shifting from an exclusively BMI <40 cutoff to considering 5 to 10% preoperative weight loss. BMI cutoffs to TJA may also restrict access to care to our most vulnerable, marginalized populations. Moreover, only roughly 20% of patients instructed to lose weight for surgery are successful and the practice of demanding mandatory weight loss needs to be reconsidered until convincing evidence exists that supports risk reduction as a result of preoperative weight loss. Obese patients can benefit greatly from this life-changing procedure. When addressing the potential difficulties and by optimizing preoperative assessment and intraoperative management, the surgery can be conducted safely. A multidisciplinary patient-centered approach with patient engagement, shared decision-making, and informed consent is recommended.

Gender-specific distribution of knee morphology according to CPAK and functional phenotype classification: analysis of 8739 osteoarthritic knees prior to total knee arthroplasty using artificial intelligence

PURPOSE

Osteoarthritis of the knee is commonly associated with malalignment of the lower limb. Recent classifications, as the Coronal Plane Alignment of the Knee (CPAK) and Functional Phenotype classification, describe the bony knee morphology in addition to the overall limb alignment. Data on distribution of these classifications is not sufficient in large populations. The aim of this study was to analyse the preoperative knee morphology with regard to the aforementioned classifications in long leg radiographs prior to total knee arthroplasty surgery using Artificial Intelligence.

METHODS

The cohort comprised 8739 preoperative long leg radiographs of 7456 patients of all total knee arthroplasty surgeries between 2009 and 2021 from our institutional database. The automated measurements were performed with the validated Artificial Intelligence software LAMA (ImageBiopsy Lab, Vienna) and included standardized axes and angles [hip-knee-ankle angle (HKA), mechanical lateral distal femur angle (mLDFA), mechanical medial proximal tibia angle (mMPTA), mechanical axis deviation (MAD), anatomic mechanic axis deviation (AMA) and joint line convergence angle (JLCA)]. CPAK and functional phenotype classifications were performed and all measurements were analysed for gender, age, and body mass index (BMI) within these subgroups.

RESULTS

Varus alignment was more common in men (m: 2008, 68.5%; f: 2953, 50.8%) while neutral (m: 578, 19.7%; f: 1357, 23.4%) and valgus (m: 345, 11.8%; f: 1498, 25.8%) alignment was more common in women. The most common morphotypes according to CPAK classification were CPAK Type I (2454; 28.1%), Type II (2383; 27.3%), and Type III (1830; 20.9%). An apex proximal joint line (CPAK Type VII, VIII and IX) was only found in 1.3% of all cases (n = 121). In men, CPAK Type I (1136; 38.8%) and CPAK Type II (799; 27.3%) were the most common types and women were spread more equally between CPAK Type I (1318; 22.7%), Type II (1584; 27.3%) and Type III (1494; 25.7%) (p < 0.001). The most common combination of femur and tibia types was NEUmLDFA0°,NEUmMPTA0° (m: 514, 17.5%; f: 1004, 17.3%), but men showed femoral varus more often. Patients with a higher BMI showed a significantly lower age at surgery (R2 = 0.09, p < 0.001). There were significant differences between men and women for all radiographic parameters (p < 0.001).

CONCLUSION

Distribution in knee morphology with gender-specific differences highlights the wide range in osteoarthritic knees, characterized by CPAK and phenotype classification and may influence future surgical planning.

LEVEL OF EVIDENCE

Level III.

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.

Effect of Tobacco Use on Radiolucent Lines in Modern Cementless Total Knee Arthroplasty Tibial Components

Background

The link between tobacco consumption and wound complications following total knee arthroplasty (TKA) is well established. However, the effect of tobacco use on biologic fixation in cementless TKA remains unknown. This study evaluated the influence of tobacco use on the presence of radiolucent lines of tibial components in cementless TKA.

Methods

A total of 293 consecutive cementless TKAs of 2 contemporary designs were retrospectively reviewed. Tibial radiolucent lines and component alignment were measured using an established measurement protocol. Patients with any history of tobacco use or active tobacco use (tobacco users) were compared to those with no history of tobacco use (tobacco nonusers). No significant differences which influenced outcomes were detected between the tobacco user and tobacco nonuser groups (P ≥ .071).

Results

Radiolucent lines decreased from 1-month to latest follow-up (mean 2.5 years) in all 10 radiographic zones regardless of tobacco use (P ≤ .084). However, evaluating intrapatient change in radiolucent line width, the tobacco nonuser group had more radiolucent lines resolve by the latest follow-up in nearly all radiographic zones, although most differences did not reach statistical significance, except for anteroposterior zone 1 (-31% vs -19%, P = .022). No tibial components were revised for aseptic loosening.

Conclusions

Results from this study suggest that any tobacco use prior to cementless TKA has the potential to hinder biologic fixation of tibial components. While no tibial components were revised for aseptic loosening, follow-up was relatively short at 2.5 years and therefore warrants further study to discern the effect of persistent radiolucent lines on long-term fixation.

The Evolution, Current Indications and Outcomes of Cementless Total Knee Arthroplasty

Total knee arthroplasty (TKA) has been performed by orthopedic surgeons for decades, but the cementless TKA has only recently gained much interest in the world of arthroplasty. Initially, early designs had multiple complications, particularly with aseptic loosening due to osteolysis and micromotion. However, modifications have shown good outcomes and excellent survivorship. Over the last several decades, changes in implant designs as well as implant materials/coatings have helped with bone in growth and stability. Furthermore, surgeons have been performing TKA in younger and more obese patients as these populations have been increasing. Good results from the cementless TKA compared to cemented TKA may be a better option in these more challenging populations, as several studies have shown greater survivorship in patients that are younger and have a greater BMI. Additionally, a cementless TKA may be more cost effective, which remains a concern in today's healthcare environment. Overall, cemented and cementless TKA have great results in modern times and there is still a debate as to which implant is superior.

Does Body Mass Index Influence the Outcomes and Survivorship of Modern Cementless Total Knee Arthroplasty?

BACKGROUND

Higher body mass index (BMI) has been associated with higher rates of aseptic loosening following cemented total knee arthroplasty (TKA). However, there is a paucity of evidence on the effect of BMI on the durability of modern cementless TKA. We aimed to assess the association between BMI and clinical outcomes following cementless TKA and to determine if there was a BMI threshold beyond which the risk of revision significantly increased.

METHODS

We identified 1,408 cementless TKAs of a modern design from an institutional registry. Patients were classified into BMI categories: normal (n = 136), overweight (n = 476), obese class I (n = 423), II (n = 258), and III (n = 115). The Knee Injury and Osteoarthritis Outcome Score for Joint Replacement and 12-item Short Form Health Survey scores were collected preoperatively and 2 years postoperatively. Survivorship was recorded at minimum 2 years (range, 24 to 88 months). BMI was analyzed as a continuous and categorical variable.

RESULTS

The improvement in patient-reported outcomes was similar across the groups. Thirty four knees (2.4%) were revised and 14 (1.0%) were for aseptic failure. Mean time-to-revision was 1.2 ± 1.3 years and did not differ across BMI categories (P = .455). Survivorship free from all-cause and aseptic revision was 97.1% and 99.0% at mean 4 years, respectively. Using Cox regression to control for demographics and bilateral procedures, BMI had no association with all-cause revision (P = .612) or aseptic revision (P = .186). Receiver operating characteristic curve analysis found no relationship between BMI and revision risk (c-statistic = 0.51).

CONCLUSION

BMI did not influence functional outcomes and survivorship of modern cementless TKA, possibly due to improved biological fixation at the bone-implant interface. Longer follow-up is necessary to confirm these findings.

Early Tibial Component Fractures in a Cementless, 3D-Printed, Titanium Implant

Fracture of the tibial baseplate in total knee arthroplasty is a rare occurrence, particularly in short- and mid-term follow-up. This case series documents the first known report in the literature of fatigue fracture of a cementless, 3D-printed, highly porous titanium tibial component. We recommend regular follow-up visits with radiographs to confirm adequate total knee arthroplasty component positioning and alignment.