Which Asymmetric Tibial Component Is Optimally Designed for Calipered Kinematically Aligned Total Knee Arthroplasty?

Author(s):  
Alexander J. Nedopil ◽  
Tomas Zamora ◽  
Connor Delman ◽  
Stephen M. Howell ◽  
Maury L. Hull

AbstractCalipered kinematically aligned (KA) total knee arthroplasty (TKA) restores the patient's prearthritic joint lines and sets internal-external rotation of the tibial component parallel to the flexion-extension (FE) plane, which is not a mechanical alignment (MA) target. Two asymmetric tibial components designed for MA set the tibial component to either a femoral component (FC) target or a tibial tubercle (TT) target. The study determined the optimal asymmetric tibial component to use with KA as the one with smaller IE deviation from the MA target, greater coverage of tibial resection, and lower incidence of cortical overhang. The study included 40 patients treated with bilateral calipered KA TKA with different asymmetric tibial components in opposite knees. A best-fit of a kinematic tibial template to the tibial resection set the template's slot parallel to the knee's FE plane. Each asymmetric tibial component's anterior-posterior (AP) axis was set parallel to the slot. Computer tomography analysis determined the IE deviation (−internal/+ external) of each tibial component from its MA target, tibial resection coverage by the baseplate and insert, and incidence of cortical overhang. The patient-reported Forgotten Joint Score (FJS) and Oxford Knee Score (OKS) determined outcomes. The mean IE deviation from the MA target was 2 degrees external for the FC-target asymmetric tibial component and −8 degrees internal for the TT-target asymmetric tibial component (p < 0.001). Tibial resection coverage by the baseplate (insert) was 88% (84%) for the FC target and 84% (79%) for the TT target (p < 0.001 for baseplate and insert). The FC target insert covered 3 mm more of the posterolateral resection (p < 0.001). Posteromedial coverage was comparable. The incidence of cortical overhang was 2.5% for each baseplate. There was no difference in FJS and OKS. When performing calipered KA, the more optimal design was the asymmetric tibial component with the FC target because of the smaller deviation from its MA target and the greater coverage of the tibial resection by the baseplate and insert.

Author(s):  
Antonio Klasan ◽  
Mei Lin Tay ◽  
Chris Frampton ◽  
Simon William Young

Abstract Purpose Surgeons with higher medial unicompartmental knee arthroplasty (UKA) usage have lower UKA revision rates. However, an increase in UKA usage may cause a decrease of total knee arthroplasty (TKA) usage. The purpose of this study was to investigate the influence of UKA usage on revision rates and patient-reported outcomes (PROMs) of UKA, TKA, and combined UKA + TKA results. Methods Using the New Zealand Registry Database, surgeons were divided into six groups based on their medial UKA usage: < 1%, 1–5%, 5–10%, 10–20%, 20–30% and > 30%. A comparison of UKA, TKA and UKA + TKA revision rates and PROMs using the Oxford Knee Score (OKS) was performed. Results A total of 91,895 knee arthroplasties were identified, of which 8,271 were UKA (9.0%). Surgeons with higher UKA usage had lower UKA revision rates, but higher TKA revision rates. The lowest TKA and combined UKA + TKA revision rates were observed for surgeons performing 1–5% UKA, compared to the highest TKA and UKA + TKA revision rates which were seen for surgeons using > 30% UKA (p < 0.001 TKA; p < 0.001 UKA + TKA). No clinically important differences in UKA + TKA OKS scores were seen between UKA usage groups at 6 months, 5 years, or 10 years. Conclusion Surgeons with higher medial UKA usage have lower UKA revision rates; however, this comes at the cost of a higher combined UKA + TKA revision rate that is proportionate to the UKA usage. There was no difference in TKA + UKA OKS scores between UKA usage groups. A small increase in TKA revision rate was observed for high-volume UKA users (> 30%), when compared to other UKA usage clusters. A significant decrease in UKA revision rate observed in high-volume UKA surgeons offsets the slight increase in TKA revision rate, suggesting that UKA should be performed by specialist UKA surgeons. Level of evidence III, Retrospective therapeutic study.


2019 ◽  
Vol 33 (05) ◽  
pp. 466-473
Author(s):  
Chao-Hua Fang ◽  
Cheng-Kung Cheng ◽  
Tie-Bing Qu ◽  
Jun-Hui Zhang ◽  
Bo Zhang ◽  
...  

AbstractRotational malalignment between the femoral and tibial components in total knee arthroplasty (TKA) can affect clinical outcomes, but there is no consensus on how to best determine tibia tray orientation. The posterolateral corner-locked (PLCL) technique may be a new method. This study aims to assess the applicability of this technique in a Chinese population. Forty normal Chinese volunteers were recruited and underwent computed tomography (CT) of the lower limbs. Knee model reconstructions and simulated standard tibial osteotomy were conducted digitally. The transepicondylar axis (TEA), the Akagi line, and the line connecting the medial third of the tibial tubercle with the midpoint of the posterior cruciate ligament (PCL) were projected to the tibial cross-section and marked. The PLCL technique was applied using either symmetrical or asymmetrical tibial tray templates, and the anteroposterior (AP) axis of the tibial tray was marked. The angles between the TEA and these lines were calculated, and the statistical differences were analyzed. The angle between the TEA and the Akagi line and between the TEA and the line connecting the medial third of the tibial tubercle with the midpoint of the PCL were 96.90 ± 5.57 and 107.31 ± 5.95 degrees, respectively. The angles between the TEA and the AP axis of the symmetrical and the asymmetrical design tibial trays were 94.01 ± 4.21 and 96.65 ± 4.70 degrees, respectively. Except for the Akagi line and AP axis of the asymmetrical tibial tray, statistical differences were found between all lines (p < 0.05). The PLCL technique is principally suitable for Chinese patients requiring TKA when using the tibial component referred to in this study, although it may result in slight external rotation.


PLoS ONE ◽  
2018 ◽  
Vol 13 (12) ◽  
pp. e0209317 ◽  
Author(s):  
Takaaki Ohmori ◽  
Tamon Kabata ◽  
Yoshitomo Kajino ◽  
Daisuke Inoue ◽  
Tadashi Taga ◽  
...  

Joints ◽  
2013 ◽  
Vol 01 (04) ◽  
pp. 155-160 ◽  
Author(s):  
Andrea Baldini ◽  
Pier Indelli ◽  
Lapo De Luca ◽  
Pierpaolo Mariani ◽  
Massimiliano Marcucci

Purpose: to compare the anterior tibial surface curvature, the Akagi’s line and the medial third of the tibial tubercle in order to assess which is the most reliable landmark for correct tibial component rotational positioning in total knee arthroplasty. Methods: three independent investigators reviewed 124 knee MRI scans. The most suitable tibial baseplate tracing for the Nexgen Total Knee System (Zimmer, Warsaw, USA) was superimposed on the scan matching the anterior tibial cortex with the anterior aspect of the baseplate. The rotation of the tibial baseplate tracing was calculated with respect to the transepicondylar axis (TEA), the medial third of the tibial tubercle line, Akagi’s line and the femoral posterior condylar axis (PCA). Customized software was created and used for analysis of the MRI datasets.The reliability of each measurement was then calculated by using the intraclass correlation coefficient for interobserver agreement. Results: observer agreement on the position of the Akagi’s line was within 3° in 64% of the cases and within 5°in 85% of the cases. Agreement on the position of the medial third of the tibial tubercle was within 3°in 29% of the cases and within 5°in 70% of the cases. Agreement on the localization of the anterior tibial surface curvature was within 3°in 89% of the cases and within 5°in 99% of the cases. Component alignment along the anterior cortex guaranteed full matching ± 3° with the epicondylar axis in 75% of the knees. Conclusions: the anterior tibial surface curvature was found to be a more reliable and more easily identifiable landmark for correct tibial component alignment than either Akagi’s line or the medial third of the tibialtubercle. Level of evidence: level III, retrospective cohort study.


2014 ◽  
Vol 4 (1) ◽  
pp. 8-12
Author(s):  
Andrea Baldini ◽  
Pier Francesco Indelli ◽  
PT Luca Manfredini ◽  
Massimiliano Marcucci

ABSTRACT Purpose We hypothesized that the anterior tibial surface curvature is a more reliable landmark for correct tibial component rotational positioning in TKA respect to the ‘Akagi’ line and the medial third of the tibial tubercle. Methods Three independent investigators reviewed 124 knee MRI scans, identifying independently the femoral transepicondylar axis (TEA), the femoral posterior condylar axis (PCA), a line connecting the middle of the posterior cruciate ligament and the medial edge of the patellar tendon attachment (Akagi's line), the medial third of the tibial tubercle and the anterior tibial surface curvature. The most appropriate tibial baseplate tracing for the NexGen Total Knee System (Zimmer, Warsaw, USA) was superimposed matching the anterior tibial cortex with its anterior surface. At this point, the rotation of the tibial plate tracing was calculated in respect to the TEA, the medial third of the tibial tubercle line, the Akagi's line and the PCA. Customized software was created and used for analysis of the MRI datasets. Results: The investigators agreed on the localization of the Akagi's line in 64% of the cases within 3° and in 85% of the cases within 5° (minimum –16°, maximum –7°): this landmark might lead to internal rotation of the tibial component. The observers agreed on the localization of the medial third of the tibial tubercle in 29% of the cases within 3° and, in 70% of the cases, within 5° (minimum –4°, maximum +4°): this landmark might lead to external rotation of the tibial component. The investigators agreed on the localization of the anterior tibial surface curvature in 89% of the cases within 3° and in 99% of the cases within 5° (minimum –1°, maximum +4°): component alignment along the anterior cortex guaranteed full matching ±3° to the epicondylar axis in 75% of the knees. Conclusion Alignment of the tibial component, when based on the anterior tibial surface, was more reliable and easier identifiable than either the Akagi's line or the medial third of the tibial tubercle. Level of evidence Level 3 (Retrospective cohort study). Indelli PF, Baldini A, Manfredini L, Marcucci M. Rotational Alignment Landmarks in Primary Total Knee Arthroplasty. The Duke Orthop J 2014;4(1):8-12.


Author(s):  
Tomofumi Kage ◽  
Hiroshi Inui ◽  
Tetsuya Tomita ◽  
Takaharu Yamazaki ◽  
Shuji Taketomi ◽  
...  

AbstractBicruciate-stabilized total knee arthroplasty (BCS TKA) has been developed to improve TKA kinematic performance. However, the relationship between in vivo kinematics and patient-reported outcomes (PROs) has not been well described. This study was performed to clarify the relationship between in vivo kinematics and PROs in a cohort of patients undergoing BCS TKA. Forty knees were evaluated using a two-dimensional to three-dimensional registration technique obtained from sagittal plane fluoroscopy. In vivo kinematics including anteroposterior (AP) translation and tibiofemoral rotation were evaluated. Knee Society scores (KSSs) and Knee injury and Osteoarthritis Outcome Scores (KOOSs) were assessed before and after surgery. Relationships between tibiofemoral kinematics assessed with the knee in different positions of knee flexion and PROs were evaluated using Spearman's correlation analysis. The study demonstrated a significant negative correlation (r =  − 0.33) between medial AP translation from minimum flexion to 30 degrees flexion and postoperative KOOS activities of daily living subscale. A significant positive correlation (r = 0.51) was found between the femoral external rotation from minimum flexion to 30 degrees flexion and improvement of the KOOS pain subscale. No correlation was found between the lateral AP translation and PROs. Achieving medial AP and femoral external rotation stability in early flexion may be important in optimizing postoperative PROs.


2019 ◽  
Vol 33 (05) ◽  
pp. 513-524 ◽  
Author(s):  
Corey Scholes ◽  
Milad Ebrahimi ◽  
Nalan Ektas ◽  
John Ireland

AbstractThere is a lack of clinical outcomes reported for the rotating bearing knee (RBK) total knee arthroplasty (TKA), which is a second-generation rotating platform knee, with purported benefits over earlier versions. The purpose of the study was to report the complications, short-term (minimum 1 year) patient-reported outcomes and long-term (up to 15 years) procedure survival in a consecutive series of patients receiving a rotating platform TKA (RBK) from an independent clinic. A retrospective analysis of a single-surgeon, private/public practice, with prospectively collected data in a subset of patients were performed. A total of 1,130 procedures (primary, revision from unicompartmental knee arthroplasty (UKA) to TKA) were crossmatched with manufacturer records. Clinical outcomes (complications, reoperations) were summarized and linked to patient-reported outcome measures (Eq. 5D, KSS-function, Oxford knee score [OKS]). OKS results were classified using minimally clinical important difference (MCID) and patient acceptable symptom state (PASS). PROMs were summarized and regression models used to determine relationships between patient factors and outcomes in this cohort. Cumulative percent revision was reported by the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) and compared between the senior author and national data using Kaplan–Meier survival analysis. We report a complication rate of 19.7% with the majority (> 60%) being thromboembolic events and complaints of stiffness. Significant improvements were observed in general health, knee pain, and function with > 89% exceeding the MCID for the OKS and > 65% exceeding the PASS for the OKS at an average follow-up of 3.2 years. We report a cumulative revision rate of 4.3% at 5 years and 4.8% at 14 years, with significantly lower revision rates in females and patients aged 55 to 64 years compared with AOANJRR data for fixed bearing designs. The RBK rotating platform TKA provides good functional outcomes, with relatively low revision and complications rates at up to 14 years follow-up. This design in conjunction with a gap balancing technique may be advantageous in certain patient subgroups.


2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Joshua D. Roth ◽  
Stephen M. Howell ◽  
Maury L. Hull

In total knee arthroplasty (TKA), one common metric used to evaluate innovations in component designs, methods of component alignment, and surgical techniques aimed at decreasing the high rate of patient-reported dissatisfaction is tibiofemoral contact kinematics. Tibiofemoral contact kinematics are determined based on the movement of the contact locations in the medial and lateral compartments of the tibia during knee flexion. A tibial force sensor is a useful instrument to determine the contact locations, because it can simultaneously determine contact forces and contact locations. Previous reports of tibial force sensors have neither characterized nor corrected errors in the computed contact location (i.e., center of pressure) between the femoral and tibial components in TKA that, based on a static analysis, are caused by the curved articular surface of the tibial component. The objectives were to experimentally characterize these errors and to develop and validate an error correction algorithm. The errors were characterized by calculating the difference between the errors in the computed contact locations when forces were applied normal to the tibial articular surface and those when forces were applied normal to the tibial baseplate. The algorithm generated error correction functions to minimize these errors and was validated by determining how much the error correction functions reduced the errors in the computed contact location caused by the curved articular surface. The curved articular surface primarily caused bias (i.e., average or systematic error) which ranged from 1.0 to 2.7 mm in regions of high curvature. The error correction functions reduced the bias in these regions to negligible levels ranging from 0.0 to 0.6 mm (p < 0.001). Bias in the computed contact locations caused by the curved articular surface of the tibial component as small as 1 mm needs to be accounted for, because it might inflate the computed internal–external rotation and anterior–posterior translation of femur on the tibia leading to false identifications of clinically undesirable contact kinematics (e.g., internal rotation and anterior translation during flexion). Our novel error correction algorithm is an effective method to account for this bias to more accurately compute contact kinematics.


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