Comparison of revision rates and epidemiological data of a single total knee arthroplasty system of different designs (cruciate retaining, posterior stabilized, mobile bearing, and fixed bearing): a meta-analysis and systematic review of clinical trials and national arthroplasty registries.

BACKGROUND: This study aimed to meta-analyze epidemiological data, revision rates, and incidences of different designs of a single Total Knee Arthroplasty System and compare these factors across different countries. METHODS: A systematic review was conducted on clinical studies and arthroplasty registries of ATTUNE TKA from 1999 to 2020. The main endpoints analyzed were revision rates and epidemiological data. RESULTS: The average age of patients was 67.8 years, with a gender distribution of 60% female and 40% male. The pooled average BMI was 29.4 kg/m2. Eight clinical studies showed a pooled revision rate per 100 observed CY of 0.5 (n = 1343 cases). Cumulative revision rates after 1, 3, and 5 years varied among registries, with the Swiss registry having the highest revision data (after 5 years: 6.3%) and the American registry having the lowest revision data (after 5 years: 1.7%). A comparison of the revision rates of mobile bearing and fixed bearing (41,200 cases) as well as cruciate retaining and posterior stabilized (n = 123,361 cases) showed no significant advantage in the first 5 years after implantation. CONCLUSION: In conclusion, pooled data from 41,200 cases of TKA with a single Total Knee Arthroplasty System in two arthroplasty registries revealed that there was no significant difference in revision rates between the mobile bearing and fixed bearing design within the first 5 years after implantation. In addition, a comparison of the revision rates in n = 123,361 cases showed no significant advantage for cruciate retaining or posterior stabilized in the first 5 years after implantation.

Improved postoperative kneeling ability in posterior stabilized total knee arthroplasty with medialized dome-patella resurfacing: A retrospective comparative outcome analysis.

OBJECTIVES: This investigation aimed to evaluate if the modifications to prosthesis designs improve patients' clinical and functional outcomes after total knee arthroplasty (TKA), with a special focus on pain and kneeling ability. METHODS: Retrospective and comparative analysis of consecutive patients who were treated with posterior stabilized TKA using two different prostheses designs (single surgeon, single vendor). Group 1 received a traditional design TKA (PFC Sigma; DePuy, Inc., Warsaw, IN) with conventional dome-patella resurfacing, and group 2 received a modern design implant (Attune; DePuy, Inc., Warsaw, IN) with medialized dome-patella resurfacing. Functional outcome (range of motion: ROM) and the Oxford Knee Score (OKS) were collected preoperatively, at 4-6 weeks and 12 months following surgery. RESULTS: Ninety-nine participants were included. Of these, 30 received traditional-design implants and 69 received modern-design knee implants. The comparison between the two implants showed a statistically significant increase in total OKS and kneeling ability in the modern design cohort at 1-year follow-up compared to the traditional design cohort (p â€‹< â€‹0.01). In the modern design group, 53% (N â€‹= â€‹37) could kneel easily or with little difficulty, compared to 30% (N â€‹= â€‹9) in the traditional design group. No statistically significant differences in ROM or the OKS pain component were seen. CONCLUSION: The incorporation of a medialized dome-patella in modern knee implant design may offer advantages over traditional designs, as seen in improved total OKS and kneeling ability at one-year follow-up. Further research with larger cohorts is needed to confirm these findings and explore the broader impact of implant design changes on patient outcomes. LEVEL OF EVIDENCE: Clinical Study, Level III.

Medial tibial bone resorption following total knee arthroplasty comparing a traditional with a kinematic design.

BACKGROUND: New total knee prostheses are being designed to improve clinical outcome, survivorship and patient satisfaction following total knee arthroplasty (TKA). A new knee system was developed with improvements in patellofemoral joint, trochlear geometry, polyethylene formulation and tibial baseplate. Aim of this study was to compare the newer kinematic knee system with its existing predecessor knee system in terms of clinical outcome, revision rates, radiographic outcomes specifically medial tibial bone resorption. METHODS: The prospective matched-pair study included 88 TKA surgeries using newer kinematic design knee prostheses, performed between January 2015 and December 2016, out of which 82 patients were available for final follow-up. The control cohort of 82 traditional TKA prosthesis was matched in terms of age, gender and body mass index. All surgeries were performed by the single surgeon using medial parapatellar arthrotomy and posterior stabilized implants were used. Clinical outcomes were assessed using knee society score, range of motion (ROM), anterior knee pain and crepitation. Radiological examinations included recording of radiolucent lines and medial tibial bone resorption. RESULTS: At the 5-year follow-up, no significant differences were noted in terms of mean knee society score (93.3 ± 6.6 vs 94.2 ± 8.1), knee function score (88.5 ± 10.5 vs 89.1 ± 11.2) and ROM. The incidences of anterior knee pain and crepitation were lower in the newer group (8.5% vs 21.9% and 14.6% vs 32.9%, respectively) compared to the traditional prosthesis group. No cases of aseptic loosening were observed in either cohort. No significant difference was seen in terms of radiolucent lines (29.3% vs 26.8%) and medial tibial resorption (2.43% in each group) incidences. CONCLUSIONS: At the 5 years follow-up no significant differences were noted between the two groups in terms of clinical and radiological outcomes, except the former proved to be better for anterior knee pain and crepitation. LEVEL OF EVIDENCE: II.

Does lucency equate to revision? A five-year retrospective review of Attune and Triathlon total knee arthroplasty.

PURPOSE: The Attune® total knee arthroplasty system was introduced in 2013 to address lingering issues of patient dissatisfaction. However, recent literature reports concerns of early tibial tray debonding. The aim of this study was to compare the incidence of radiolucent lines, survivorship and patient reported outcome-measures between the Attune® system and the well-established Triathlon® system. METHODS: This retrospective database review was conducted at a single institution in Cork, Ireland. All primary Attune® (N = 445) and Triathlon® (N = 285) systems implanted between 2015 and 2016 were reviewed. Radiolucent lines were assessed for those with a minimum two-year radiological follow-up (Attune® = 338; Triathlon® = 231). X-rays were taken post op, at 6 months, 2 years and 5 years. Radiolucent lines were documented using the Modern Knee Society Radiographic System. Five-year survival was assessed using Kaplan-Meier analysis with the Log Rank method to determine statistical significance. The Oxford Knee Score and EQ-5D-5L, were collected pre-op, at 6 months, 2 years and 5 years post-operatively and compared using the Kruskal-Wallis Test. RESULTS: The Attune® had a higher proportion of radiolucent lines at the tibial tray [87.1% (54/62) vs 61.4% (27/44); p = 0.001] and at the implant-cement interface [62.9% (39/62) vs 43.2% (19/44); p = 0.02]. Conversely, the Triathlon® had a higher proportion AT the femur [38.6% (17/44) vs 12.9% (8/62); p = 0.001] and at the cement-bone interface [56.8% (25/44) vs 37.1% (23/62); p = 0.02]. The overall frequency of radiolucent lines was similar in both the Attune® and Triathlon® groups [17.8%, (60/338) vs 17.7%, (41/231); p = 0.49]. There was no difference in revision-free survival analysis at 5 years (Attune® 97.8% vs Triathlon® 95.8%; p = 0.129). The Attune® performed better at 5 years in the Oxford Knee Score [Attune® = 42.6 (SD 5.2) vs Triathlon® = 41 (SD 6.4); p = 0.001] and in the EQ-5D [Attune® = 0.773 (SD 0.187) vs Triathlon® = 0.729 (SD 0.218); p = 0.013]. There was no difference at 5 years in the EQ-VAS [Attune® = 80.4 (SD 13.7) vs Triathlon® = 78.5 (SD 15.3); p = 0.25]. CONCLUSION: The Attune® system exhibited a higher incidence of  radiolucent lines at the tibial tray. However, this did not lead to decreased survivorship at medium term follow-up compared to the Triathlon®. Furthermore, improvements in patient reported outcomes modestly favoured the Attune® system. LEVEL OF EVIDENCE: III.

Modern implants in total knee arthroplasty are more patellofemoral joint friendly compared to their traditional design: a systematic review and meta-analysis.

BACKGROUND: Implant designs for total knee arthroplasties (TKA) are continuously evolving to improve outcomes and satisfaction rates after TKA. The present systematic review and meta-analysis aimed to explore the evidence in the literature regarding the outcomes of the Attune knee system over the PFC Sigma knee design and investigate the advantage of one over the other. METHODS: A systematic review and meta-analysis of published studies till August 2021 was performed using the defined eligibility criteria. This was a systematic review of the literature published in the Cochrane Central Register of Controlled Trials (CENTRAL) Library, PUBMED, and EMBASE. The analysis included prospective and retrospective comparative trials comparing TKA by PFC sigma or Attune posterior stabilized (PS) or cruciate-retaining (CR), fixed bearing, or rotating platform systems. Patient-reported outcome measures (PROM) and postoperative patellar complications were analysed in the studies utilizing attune knee system (modern implants) to its counterpart PFC sigma (traditional implants) for TKA. Quality assessment was conducted using NIH Quality Assessment Tool for controlled intervention studies (RCTs and case-control studies). RESULTS: This review included 3 RCTs and the rest, 10 of which were non-RCT, including 5852 patients. ATTUNE designs suggested a statistically significant improvement in KSS over PFC Sigma designs. Other PROMs such as OKS and WOMAC scores yielded comparable results between the two groups. ATTUNE knee prosthesis did not result in better knee range of motion, patient satisfaction, or radiological outcomes than the PFC design. Regarding the complications, attune knee prosthesis demonstrated favourable results over PFC Sigma for anterior knee pain and patellofemoral (PF) crepitus. CONCLUSIONS: The present systematic review highlights better KSS and lesser chances of PF complications favouring a modern implant design over its traditional counterpart. Other patient-reported outcome analyses at a short-term follow-up period were comparable among patients undergoing total knee replacements with two different implant designs. Radiological outcomes for component positioning also suggested similar results among the two groups.

Cross-sectional Analysis Study Between SIGMA Knee System and ATTUNE in a Cruciate-Retaining Fixed-Bearing Total Knee Replacement, with no Patellar Resurfacing.

Background: The purpose of our study was to compare the knee implant SIGMA to the ATTUNE knee implant in a cruciate-retaining (CR) fixed-bearing (FB) total knee replacement (TKR) surgery, with no patellar resurfacing. Methods: We examined 40 patients (19 SIGMA; 21 ATTUNE) who underwent a TKR FB CR surgery, without patellar resurfacing, due to osteoarthritis, between August 2013 and July 2017. All surgeries were performed by a single surgeon. We performed a cross-sectional analytical study based on preoperative patient data and data collected in follow-up sessions. All patients were asked to fill a quality-of-life (QOL) questionnaire, SF-36 translated to the Hebrew language. All patients were clinically evaluated using the Knee Society Score (KSS) and the Knee Function Score (KFS). Results: Patients from the SIGMA cohort reported fewer postoperative physical function limitations in the SF-36 (p = 0.01) and the KFS (p = 0.04). Patients who underwent surgery using the SIGMA implant reported increased vitality when compared to the ATTUNE (p = 0.02). No significant differences were found between the groups in other measures of quality of life, ranges of motion, valgus, and postoperative knee stability. The average follow-up period was significantly longer for the SIGMA (p < 0.00001). Conclusion: Significant differences were found in postoperative physical function and vitality scores between SIGMA and ATTUNE knee implants. SIGMA cohort presented superior results. Presumably, these findings are due to the differences in follow-up times.

Technology-enhanced learning in orthopaedics: Virtual reality and multi-modality educational workshops may be effective in the training of surgeons and operating department staff.

AIM: The aims were to assess the utility of: 1) virtual reality-mediated simulation, and 2) a multi-modality 'Bootcamp' in the delivery of total knee arthroplasty (TKA) teaching to orthopaedic surgical trainees. BACKGROUND: Surgical training opportunities are diminished as a result of the COVID-19 pandemic which may result in delays to training completion and gaps in the permanent workforce. Modern and technology-enhanced learning methods have been identified as having the potential to support high-quality and sustainable education. METHODS: This mixed-methods study assessed the educational benefit of two activities designed to teach TKA to junior (ST1-3) orthopaedic trainees. A multi-modality training Bootcamp was delivered that included: virtual reality (VR) and saw-bone simulation; tutorials, and case-based symposia. The VR component was delivered to different participants (surgical trainees, scrub nurses, and consultants) on a further two separate occasions. Qualitative and quantitative data were collected pertaining to utility and performance. RESULTS: Trainees reported that the Bootcamp improved comprehension of arthroplasty principles including component alignment, knee balancing, and intraoperative strategies. Case-based discussions helped develop diagnostic and decision-making skills. The VR activity improved understanding of the surgical process map, increased ability to anticipate steps, and consider the procedure strategically. All staff groups found the VR activity beneficial and would recommend it as a useful addition to a surgical department. CONCLUSION: VR-mediated simulation could augment the education of surgical trainees and scrub team staff by improving comprehension of the surgical process map. Integrated multi-modality 'Bootcamp-style' training activities constructed around trainees' needs may provide a sustainable solution to bridge the experience gap related to reduced exposure to elective orthopaedic practice.

Early and mid-term results with the ATTUNE total knee replacement system compared to PFC Sigma: a prospective comparative study.

PURPOSE: Up to 20% of all patients are not satisfied with the result after total knee arthroplasty (TKA). To improve patient satisfaction manufacturers have modified prosthesis design. The ATTUNE prosthesis is a modified version of the PFC Sigma. Aim of this study was to evaluate the outcome at 6 months and 5 years after TKA with ATTUNE compared to PFC Sigma. METHODS: Sixty patients were included prospectively (30 ATTUNE vs. 30 PFC Sigma). Knee Society Score and Hospital for Special Surgery Score were recorded preoperatively, at 6 months and at least 5 years postoperatively. At 5-years follow-up X-rays in two planes were evaluated, radiolucent lines were documented. RESULTS: Patient characteristics were similar in both groups. Both ATTUNE and PFC Sigma provided good to excellent clinical results. There were no statistically significant differences based on the overall scores and patient rated outcome measures. Nevertheless, patients in the ATTUNE group tended to be symptom-free earlier and to achieve better clinical results after 5 years. CONCLUSION: Even with the scores not being significantly different here, the modified design of ATTUNE could increase long-term satisfaction with the implant and reduce the need for revision surgery. However, long-term results are required to prove this.

Does tibial design modification improve implant stability for total knee arthroplasty? An experimental cadaver study.

AIMS: One of the main causes of tibial revision surgery for total knee arthroplasty is aseptic loosening. Therefore, stable fixation between the tibial component and the cement, and between the tibial component and the bone, is essential. A factor that could influence the implant stability is the implant design, with its different variations. In an existing implant system, the tibial component was modified by adding cement pockets. The aim of this experimental in vitro study was to investigate whether additional cement pockets on the underside of the tibial component could improve implant stability. The relative motion between implant and bone, the maximum pull-out force, the tibial cement mantle, and a possible path from the bone marrow to the metal-cement interface were determined. METHODS: A tibial component with (group S: Attune S+) and without (group A: Attune) additional cement pockets was implanted in 15 fresh-frozen human leg pairs. The relative motion was determined under dynamic loading (extension-flexion 20° to 50°, load-level 1,200 to 2,100 N) with subsequent determination of the maximum pull-out force. In addition, the cement mantle was analyzed radiologically for possible defects, the tibia base cement adhesion, and preoperative bone mineral density (BMD). RESULTS: The BMD showed no statistically significant difference between both groups. Group A showed for all load levels significantly higher maximum relative motion compared to group S for 20° and 50° flexion. Group S improved the maximum failure load significantly compared to group A without additional cement pockets. Group S showed a significantly increased cement adhesion compared to group A. The cement penetration and cement mantle defect analysis showed no significant differences between both groups. CONCLUSION: From a biomechanical point of view, the additional cement pockets of the component have improved the fixation performance of the implant. Cite this article: Bone Joint Res 2022;11(4):229-238.

Cement debonding behaviors of the various tibial components of the ATTUNE knee system and its predecessors: Is a cement-in-cement revision an alternative?

BACKGROUND: Aseptic loosening remains one of the most common causes of revision of the tibial component for total knee arthroplasty. A stable bond between implant and cement is essential for appropriate long-term results. The aim of our in vitro study was to investigate the maximum failure load of tibial ATTUNE prosthesis design alternatives compared with a previous design. In addition, cement-in-cement revision was considered as a potential strategy after tibial component debonding. METHODS: The experimental investigations of the maximum failure load of the implant-cement interface were performed under optimal conditions, without potential contamination. We compared the designs of the tibial components of the ATTUNE, ATTUNE S+ and P.F.C. Sigma. In addition, we investigated the cement-in-cement revision for the ATTUNE knee system replacing it with an ATTUNE S+. RESULTS: The maximum failure load showed no significant difference between P.F.C. Sigma and ATTUNE groups (P = 0.087), but there was a significant difference between the P.F.C. Sigma and the ATTUNE S+ groups (P < 0.001). The analysis also showed a significant difference (P < 0.001) between the ATTUNE and the ATTUNE S+ groups for the maximum failure load. The ATTUNE S+ cement-in-cement revision group showed a significant higher failure load (P < 0.001) compared with the P.F.C. Sigma and ATTUNE groups. No significant differences (P = 1.000) were found between the ATTUNE S+ cement-in-cement and ATTUNE S+ group. CONCLUSION: Based on these results, we found no design-specific evidence of increased debonding risk with the ATTUNE and ATTUNE S+ components compared with the P.F.C Sigma. Furthermore, the cement-in-cement revision seems to be an alternative for the revision surgery.

Design and rationale of the ATtune Knee Outcome Study (ATKOS): multicenter prospective evaluation of a novel uncemented rotating platform knee system.

BACKGROUND: Total Knee Arthroplasty (TKA) remains the gold standard for treatment of debilitating symptoms of knee osteoarthritis (OA). Even though providing satisfactory results for the majority of patients, some studies report dissatisfaction after TKA to be as high as 20%. Among other things, pain catastrophising and self-efficacy are thought to compromise results of TKA. Implant manufacturers keep improving upon their designs in an attempt to improve functional outcomes. One of these novel knee systems is the Attune. To our knowledge, there are no clinical follow-up studies reporting results of the uncemented version. The main objective of this multicentre prospective observational study is to evaluate revision rate, complications, radiographic outcomes (i.e. alignment and radiolucent lines) and patient reported outcomes of the uncemented Attune mobile bearing TKA. Secondary objectives are (1) to assess physical function, return to sport and return to work after TKA and (2) to evaluate the long-term effect of preoperative psychological factors on satisfaction after TKA. METHODS: All patients presenting in the participating centres with knee pathology warranting joint replacement therapy will be considered for inclusion, an absolute indication for cemented fixation is the only exclusion criterium. Evaluation of clinical and radiographic performance (e.g. radiolucent lines) is done at 6 weeks, 6 months, 1 year, 5 years and 10 years after surgery using validated patient reported outcome measures. Cumulative revision rates are calculated after 5 and 10 years using Kaplan-Meier methods. Physical function is assessed with performance based measurements before and 1 year after surgery. Return to sports is assessed using the Tegner and University of California Los Angeles (UCLA) activity rating scale before and 1 year after surgery. Return to work is evaluated by inviting patients of working age to complete a short questionnaire 1 year after surgery. Psychologic factors are assessed using questionnaires for pain catastrophising, pain self-efficacy and mental health before, 5 years and 10 years after surgery. Preoperative psychologic scores are correlated to functional outcomes. DISCUSSION: The current study aims to report the clinical performance of a novel implant and can help provide insight in factors that play a role in satisfaction after TKA. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT04247672 (January 30, 2020).

Mid-term results show no significant difference in postoperative clinical outcome, pain and range of motion between a well-established total knee arthroplasty design and its successor: a prospective, randomized, controlled trial.

PURPOSE: The purpose of this study was to compare the clinical and functional outcome scores following total knee arthroplasty (TKA) with two different systems. The hypothesis was that there is a difference between patients receiving the newer design than those receiving the predecessor. METHODS: Two hundred patients who underwent TKA were randomized into two groups: patients received either Attune TKA or PFC Sigma (both DePuy Synthes, Warsaw, IN). Clinically, the Knee Society Knee and Function Scores (KS and FS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Range of Motion (ROM) and Visual Analogue Scale (VAS) were evaluated and compared between the groups 2 years after surgery. 158 patients (80 in the Attune group and 78 in the PFC Sigma group) were available for follow-up. RESULTS: Through bivariate analysis using parametric and non-parametric statistical tests, no significant differences in postoperative KS, FS, WOMAC, ROM or VAS between the two groups were detected. Both groups significantly improved regarding all evaluated endpoints 2 years after surgery. CONCLUSIONS: In the current study population, no difference in clinical outcome between the two systems was found. The expected benefits of design modifications could not be observed in clinical outcome scores 2 years postoperatively. Both designs are effective options for improving pain and function in end-stage osteoarthritis. LEVEL OF EVIDENCE: I.

A Biomechanical Comparison of the Effect of Baseplate Design and Bone Marrow Fat Infiltration on Tibial Baseplate Pullout Strength.

BACKGROUND: Early clinical results of a new total knee arthroplasty (TKA) implant design show promise for improved outcomes and patellofemoral function scores. However, reports of early tibial component-cement interface debonding requiring revision have been published. This study investigated the biomechanical properties of three different tibial baseplates to understand potential causes of failure. METHODS: PFC Sigma (control), Attune (1st generation) and Attune S+ (2nd generation) tibial baseplates were implanted into 4th generation sawbone tibia models using a standardized technique. Three of each baseplate were cemented with and without additional bovine bone marrow fat. All models were tested to failure with measured axial distraction force. Implant type, presence or absence of bovine marrow and load to failure were all recorded and compared. Two-way ANOVA followed by post-hoc pairwise comparisons were used to determine statistical significance, which was set to P < .05. RESULTS: The 2nd generation tibial baseplates required significantly more force to failure. The presence of bovine marrow significantly reduced the pullout force of the implant designs overall. No significant difference was detected between the 1st generation and control baseplates. Failure mode for each model was also noted to be different irrespective of the presence or absence of bone marrow fat. CONCLUSION: The 2nd generation baseplates required significantly more force to failure compared with older designs. The presence of bone marrow during cementation of a tibial base plate significantly decreased axial pullout strength of a tibial baseplate in this laboratory model. All 1st generation baseplates exhibited debonding at the cement-implant interface.

Has the modern design of Attune total knee replacement improved outcome in patients with isolated patellofemoral arthritis?

INTRODUCTION AND AIM: Modern knee replacements aim to improve patient function in arthritis affecting different compartments of the knee. This study evaluates the Patient Reported Outcome Measure (PROM) and functional outcome of a modern total knee replacement (Attune, DePuy) in patients with isolated patellofemoral arthritis. METHODS: A total of 50 consecutive patients with isolated unilateral patellofemoral arthritis having had Attune total knee replacements at a single institution between 2010 and 2016 were prospectively studied. Five patients who developed symptoms on the opposite side during the study and two patients lost to follow-up were excluded. One patient needed early revision for loosening, leaving a total of 42 patients to be followed up over a period of 4 years. The Oxford Knee score (OKS) and Knee Injury and Osteoarthritis Outcome Score (KOOS) recorded pre-operatively and at follow-up was compared. A Functional assessment at around 8 months after operation was undertaken. RESULTS: At average follow-up of 24 months the mean OKS score improved by 15 points and the KOOS score improved by 20 points. Final KOOS sub-score for Pain was 80, Symptom 80, and ADL 82, Sports & Recreation 32 and QOL 60. Functional assessment at mean 8 months showed that a significant number of patients were able to Kneel (50%); Sit cross legged (23%); sit on their heel (23%) and were able do a single leg dip test (86%). CONCLUSION: This unique study of a modern design total knee replacement (Attune) in patients with isolated unilateral patellofemoral arthritis shows good PROM scores at 2 years and good functional assessment results at 8 months. The PROM scores are marginally better than the published results with Attune's predecessor, in a similar cohort of patients, but falls short of the published results of patellofemoral replacement implants. Large randomised comparative studies between traditional and the modern implant design is recommended to answer the question if design modification has influenced clinical outcome in patients with patellofemoral arthritis.

Polyethylene spinout in the Attune® Cruciate-Retaining Rotating-Platform (CR RP) total knee arthroplasty performed with a cruciate-sacrificing and measured-resection technique.

INTRODUCTION: Polyethylene (PE) spinout is a known but uncommon complication when using a mobile-bearing (MB) total knee arthroplasty (TKA) design. Sacrificing the posterior cruciate ligament (PCL) is within the manufacturer's recommendations for the Attune® Cruciate-Retaining Rotating-Platform (CR RP) knee design. AIM: To discuss the potential aetiology and prevention of spinout in the Attune® CR RP knee. METHODS: We used a retrospective radiological review from two centres reporting a higher rate of spinout in the Attune® CR RP knee using a cruciate-sacrificing and measured-resection technique when compared to a gap-balancing technique. Three hundred and thirty-two patients were evaluated over a 3-year period. RESULTS: There were 8 out of 279 (2.86%) cases of spinout in our first cohort of patients using a measured-resection technique. There were 0 out of 53 cases of spinout in our second cohort of patients where a gap-balancing technique was used. One spinout was reduced closed, the other seven were initially revised to a thicker RP insert of the same design. Of these seven, three underwent a further revision TKA and one patient required a knee fusion/arthrodesis. CONCLUSIONS: This study reports a higher incidence of PE spinout in the Attune® CR RP TKA when a measured-resection technique in combination with PCL resection is performed. We recommend a gap-balancing technique with conservative soft-tissue release if the surgeon is planning to sacrifice the PCL in the Attune® CR RP.

High incidence of radiolucent lines at the implant-cement interface of a new total knee replacement.

BACKGROUND: Recently introduced total knee arthroplasty (TKA) implants have been linked with the early development of periprosthetic radiolucency (PPRL). The aim of this study was to carry out a retrospective clinical and radiographical analysis of a consecutive series of a new TKA, and to assess the incidence and distribution of PPRL. METHODS: A retrospective review of all new TKA implants performed by a single surgeon at a single hospital between March 2013 and October 2017 was performed. The minimum follow-up period was 3 months, with ongoing patient review at 6, 12 and 36 months. Sequential post-operative radiographs were performed to determine the presence of PPRL. RESULTS: A total of 122 TKAs were identified in 112 patients over the 4.5-year study period. The average follow-up time was 21 months (range 3-51 months). PPRL was noted in 29 TKAs (23.8%). When comparing the PPRL group to those without PPRL, there was a difference in body mass index, with body mass index associated with an increased likelihood of PPRL (P = 0.003). There was no difference in constraint of implant (P = 0.818), cement type (P = 0.340), patella resurfacing (P = 0.286), age (P = 0.984) gender (P = 0.376) or initial mechanical axis deviation (P = 0.054) between groups. PPRL were most commonly seen in tibial anterior-posterior (AP) zone 1 and zone 2 (96.6%), followed by femoral lateral zone 5 (58.6%), tibia lateral zone 1 (55.2%) and tibial lateral zone 2 (53.2%). No patients have required revision surgery. CONCLUSION: A high incidence of early PPRL is seen in patients undergoing primary TKA using a new implant system, mainly involving the tibial component. Ongoing clinical and radiological assessment for patients seems warranted based on these findings.

No difference in radiolucent lines after TKA: a matched-pair analysis of the classic implant and its evolutional design.

PURPOSE: Total knee arthroplasty (TKA) designs evolve continuously to improve patient outcomes. However, incidences of radiolucent lines (RLL) in the latest TKA system have recently been reported, raising concerns. The purpose of the current study was to compare radiographic outcomes of this new TKA implant to its predecessor design. METHODS: A group of 100 patients undergoing TKA using the newer design (Attune) was matched by age and gender to 191 patients with the classic design (LCS). All patients underwent computer-navigated primary TKA by the same surgeon using the same technique. Radiographs were taken before discharge, and 2 and 12 months postoperatively. Radiographic analysis was performed independently by three assessors, using the Modern Knee Society Radiographic Evaluation System and Methodology (MKSRES). RESULTS: At 12 months postoperatively, the incidence of RLL did not statistically differ between the two implants (14%, n = 14 Attune vs. 8% n = 17 LCS, n.s.). The posterior femoral flange was most commonly affected (12%; n = 12 Attune vs. 7.9%; n = 15 LCS, n.s.) followed by the anterior flange (1%; n = 1 Attune vs. 3.1%; n = 6 LCS, n.s.). The tibial baseplate was only affected in 1% (n = 1) of the Attune and 2.6% (n = 5) of the LCS (n.s.). CONCLUSION: At 12 months follow-up we found no significant difference in RLL between the two implants. Both Attune and LCS TKA systems showed RLL predominantly at the posterior femoral flange. The reasons for the RLL remain a matter of speculation; however, shortcomings in surgical and cementing techniques seem to be more important than implant-related factors. LEVEL OF EVIDENCE: III.

Comparative Analysis Investigating the Impact of Implant Design on Hospital Length of Stay and Discharge Destination in a Dutch Hospital With an Established Enhanced Recovery Program.

BACKGROUND: Global demand for total knee arthroplasty (TKA) is increasing, driven by an aging and increasingly overweight patient population, culminating in higher healthcare costs. In the Netherlands, the number of TKA surgeries performed annually increased from 21,000 in 2010 to 29,000 in 2017. This study aimed to assess the impact of implant design on hospital length of stay (LOS), surgery time, and discharge destination (home vs a rehabilitation center) in a Dutch hospital with an established enhanced recovery program and short baseline LOS. METHODS: A retrospective review of consecutive adult patients who underwent primary TKA in a Dutch hospital between 2015 and 2017 using either the comparator device or the control device. RESULTS: A total of 200 patients were enrolled in the study (100 per group). Patients who received a comparator device had a significantly shorter LOS (adjusted mean 2.76 days; 95% confidence interval [CI]: 2.45, 3.11) vs the control group (adjusted mean 3.43 days; 95% CI: 3.08, 3.81; P < .01). The proportion of patients discharged to a rehabilitation center, instead of home, was also significantly lower in the comparator device group (adjusted 4.4%; 95% CI: 1.8, 10.7 vs adjusted 11.4%; 95% CI: 6.0, 20.6; P < .05). There was no difference in surgical time between the 2 groups. None of the sensitivity analyses performed affected the original analysis outcome. CONCLUSION: This study shows a modest but significant reduction in length of stay and lower rate of discharge to a rehabilitation center in the comparator device group.

Short term patient outcomes after total knee arthroplasty: Does the implant matter?

BACKGROUND: Newer implants for total knee arthroplasty (TKA) often gain market share at higher cost with little patient-reported and long-term clinical data. We compared outcomes after TKA using two different implants: DePuy PFC Sigma and Attune. METHODS: Using a prospective data repository from an academic tertiary medical center, we analyzed 2116 TKAs (1603 Sigma and 513 Attune) from April 2011 through July 2016. Outcomes included length of surgery, length of stay, facility discharge, 90-day reoperation, range of motion (ROM) change, and patient-reported physical function (PCS). RESULTS: There was no difference in length of surgery (Attune -2.87 min, P = 0.143). Implant type was not associated with extended LOS (>3 days) (OR 0.80, P = 0.439). There was no difference in facility discharge (OR 0.65, P = 0.103). Unadjusted 90-day reoperations were 0.3% for Sigma and 1.0% for Attune cohorts (P = 0.158). Sigma implants were associated with more ROM improvement in unadjusted analyses (+2.1 degree improvement P = 0.031). Fifty nine percent of the Sigma cohort and 49% of the Attune cohort achieved the minimal clinically important (MCID) change for PCS improvement, although there was no adjusted difference in achieving MCID (Attune OR 0.84, P = 0.435). There was no adjusted difference in absolute PCS improvement (Attune +0.12 score, P = 0.864). CONCLUSIONS: Our data show no difference in physical function and most outcomes between Sigma and Attune. Attune implants had shorter absolute LOS, but there were no differences in extended LOS.

No difference in joint awareness after TKA: a matched-pair analysis of a classic implant and its evolutional design.

PURPOSE: Total knee arthroplasty (TKA) designs continuously evolve with the aim of improving patient outcomes. The purpose of the current study was to compare clinical and patient-reported outcome (PRO) results of a new TKA implant to its predecessor. The hypothesis of this study was that joint awareness and range of motion (ROM) of the newer design would be better than the classic design. METHODS: One hundred patients undergoing TKA using the newer design (Attune®) were matched by age and gender to 200 patients with the classic design (LCS®). All patients underwent computer-navigated (Vector Vision, Brain-Lab, Germany) primary TKA by the same surgeon using the same technique. Data (FJS-12, WOMAC and ROM) were collected preoperatively and at 12 months follow-up at our implant registry. RESULTS: Compared to preoperative scores, FJS-12, WOMAC and ROM improved significantly at 12 months follow-up. In the Attune group, mean FJS-12 and WOMAC at follow-up were 67.6 (SD 27.8) and 14.8 (SD 14.9) respectively, compared to 70.8 (SD 33.8) and 15 (SD 17.9) in the LCS group. Mean postoperative ROM was similar in both groups (Attune 120°, range 90°-140°, SD 10.4 and LCS 120°, range 85°-140°, SD 10.3). CONCLUSION: The newer TKA and the predecessor design achieved comparable joint awareness, WOMAC scores and ROM at 1-year follow-up. The benefits expected of the newer design could not be observed in early clinical and PROs. The clinical relevance of this study is that it questions the importance of implant design as the single most important factor for patient outcomes. LEVEL OF EVIDENCE: III.