scholarly journals Morpho-Functional Analysis of Knee Implant Design for Total Knee Arthroplasty on the Example of the Trochlear Groove Orientation

10.29007/ch2k ◽  
2018 ◽  
Author(s):  
Malte Asseln ◽  
Mark Verjans ◽  
Darius Zanke ◽  
Klaus Radermacher
Keyword(s):  
Functional Analysis ◽  
Total Knee Arthroplasty ◽  
Rapid Prototyping ◽  
Knee Arthroplasty ◽  
External Rotation ◽  
Implant Design ◽  
Computer Assisted ◽  
Trochlear Groove ◽  
Total Knee ◽  
Patellofemoral Kinematics

Total knee arthroplasty (TKA) is widely accepted as a successful surgical intervention to treat osteoarthritis and other degenerative diseases of the knee. However, present statistics on limited survivorship and patient-satisfaction emphasize the need for an optimal endoprosthetic care. Although, the implant design is directly associated with the clinical outcome comprehensive knowledge on the complex relationship between implant design (morphology) and function is still lacking.The goal of this study was to experimentally analyze the relationship between the trochlear groove design of the femoral component (iTotal CR, ConforMIS, Inc., Bedford, MA, USA) and kinematics in an in vitro test setup based on rapid prototyping of polymer-based replica knee implants.The orientation of the trochlear groove was modified in five different variations in a self-developed computational framework. On the basis of the reference design, one was medially tilted (-2°) and four were laterally tilted (+2°, +4°, +6°, +8°). For manufacturing, we used rapid prototyping to produce synthetic replicates made of Acrylnitril-Butadien-Styrol (ABS) and subsequent post-processing with acetone vapor. The morpho-functional analysis of the replicates was performed in our experimental knee simulator. Tibiofemoral and patellofemoral kinematics were recorded with an optical tracking system during a semi-active flexion/extension (~10° to 90°) motion.Looking at the results, the patellofemoral kinematics, especially the medial/lateral translation and internal/external rotation were mainly affected. During low flexion, the patella had a more laterally position relative to the femur with increasing lateral trochlear orientation. The internal/external rotation initially differentiated and converged with flexion. Regarding the tibiofemoral kinematics, only the tibial internal/external rotation showed notable differences between the modified replica implants.We presented a workflow for an experimental morpho-functional analysis of the knee and demonstrated its feasibility on the example of the trochlear groove orientation which might be used in the future for comprehensive implant design parameter optimization, especially in terms of image based computer assisted patient-specific implants.

scholarly journals Effects of the medial and lateral tibial slope on knee joint kinematics in total knee arthroplasty

2018 ◽  
Vol 4 (1) ◽  
pp. 207-211
Author(s):  
Malte Asseln ◽  
Luisa Berger ◽  
Mark Verjans ◽  
Klaus Radermacher
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Joint ◽  
Knee Arthroplasty ◽  
Tibial Slope ◽  
Joint Kinematics ◽  
Implant Design ◽  
Initial Slope ◽  
Knee Joint Kinematics ◽  
Total Knee ◽  
Patellofemoral Kinematics

AbstractImplant design in total knee arthroplasty is a key factor for the recovery of function and mobility of the joint. However, there is a lack of knowledge on the complex relationship between design features and the biomechanical situation. The posterior inclination of the tibial plateau (tibial slope) has a known functional impact on knee joint kinematics. In the native knee it shows high inter-individual differences, which is inadequately considered in total knee arthroplasty. We investigated the effects of the separate and combined variation of the medial and lateral tibial slope on knee joint kinematics in an in vitro setup. Therefore, the medial and lateral inserts of a knee implant were parameterised and the initial slope was gradually varied to +4°, +2° (posterior) and -2°, -4° (anterior). The variations were manufactured by using polymer based rapid prototyping. The effects on semi-active tibiofemoral and patellofemoral kinematics were studied and quantified in terms of the Root Mean Square Error and Pearson’s Correlation coefficient. The overall largest effect was observed on tibiofemoral internal-external rotation by the variation of the lateral insert. The anterior-posterior translation was predominantly effected by the combined variation. Nevertheless, the lateral variation showed greater influence than medial. In contrast, changes in patellofemoral kinematics were small. Our findings suggest that in total knee arthroplasty the lateral tibial slope has a larger functional effect than the medial tibial slope. Thus, functional design optimization should focus on the lateral insert.

scholarly journals Change of tibial tuberosity-trochlear groove (TT-TG) distance during total knee arthroplasty had no influence on clinical outcome and anterior knee pain

2021 ◽  
Author(s):  
Silvan Hess ◽  
Timo Fromm ◽  
Filippo Schiapparelli ◽  
Lukas B. Moser ◽  
Emma Robertson ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Clinical Outcome ◽  
Knee Arthroplasty ◽  
T Test ◽  
Tibial Tuberosity ◽  
Trochlear Groove ◽  
Femoral Mechanical Angle ◽  
Tibial Mechanical Angle ◽  
Total Knee

Abstract Purpose The main purpose of this study was to determine whether there is a correlation between the change of tibial tuberosity-trochlear groove (TT-TG) distance and clinical outcomes after total knee arthroplasty (TKA). Methods A total of 52 knees undergoing TKA due to primary osteoarthritis were included in this retrospective study. All patients had pre- and postoperative CT scans. TT-TG distance was measured by two independent observers and the following alignment parameters were measured: hip-knee ankle angle (HKA), femoral mechanical angle (FMA), tibial mechanical angle (TMA), and posterior condylar angle (PCA). Clinical outcome was assessed using Knee Society Score (KSS) pre- and post-operatively and at a minimum of 12-month follow-up. Evidence of AKP was noted from follow-up reports. Pre- and postoperative scores were compared using a paired Student t-test. Pearson correlations were calculated to assess the influence of TT-TG on clinical outcome and of alignment parameters on the change in TT-TG. TT-TG between patients with and without AKP was compared using unpaired Student’s t-test (p < 0.05). Results Neither the absolute postoperative TT-TG nor the amount of change in TT-TG correlated with the post-operative KSS or the change in KSS. Post-operative TT-TG and change in TT-TG did not differ significantly between patients with and patients without AKP. Only the change in FMA showed a correlation with the change in TT-TG (p = 0.01, r = 0.36). Conclusion Despite a missing correlation between outcomes and TT-TG distance in this study, excessive TT-TG distance should be avoided. Furthermore, surgeons need to be aware that changes in femoral joint line orientation might affect TT-TG distance.

A Prospective Randomised Control Trial Comparing Functional with Mechanical Axis Alignment in Total Knee Arthroplasty: study protocol for an investigator initiated trial

2021 ◽  
Author(s):  
Richard Steer ◽  
Beth Tippett ◽  
R Nazim Khan ◽  
Dermot Collopy ◽  
Gavin Clark
Keyword(s):  
Total Knee Arthroplasty ◽  
Soft Tissue ◽  
Knee Arthroplasty ◽  
Functional Outcomes ◽  
Medical Information ◽  
Randomised Control Trial ◽  
Computer Assisted ◽  
Patient Reported ◽  
Total Knee ◽  
Alternative Alignment

Abstract Background: A drive to improve functional outcomes for patients undergoing total knee arthroplasty (TKA) has led to alternative alignment being used. Functional alignment (FA) uses intraoperative soft tissue tension to determine the optimal position of the prosthesis within the patients soft tissue envelope. Angular limits for bone resections are followed to prevent long term prosthesis failure. This study will use the aid of robotic assistance to plan and implement the final prosthesis position. This method has yet to be compared to the traditional mechanically aligned (MA) knee in a randomised trial. Methods: A blinded randomised control trial with 100 patients will be undertaken via Perth Hip and Knee clinic. Fifty patients will undergo a MA TKA and fifty will undergo a FA TKA. Both alignment techniques will be balanced via computer assisted navigation to assess prosthetic gaps, being achieved via the initial bony resection and further soft tissue releases as required to achieve satisfactory balance. The primary outcome will be the forgotten joint score (FJS) two years after surgery, with secondary outcomes being other patient reported outcome measures, clinical functional assessment, radiographic position and complications. Other data that will be collected will be patient demography (Sex, Age, level of activity) and medical information (grade of knee injury, any other relevant medical information). The linear statistical model will be fitted to the response (FJS), including all the other variables as covariates. Discussion: Many surgeons are utilising alternative alignment techniques with a goal of achieving better functional outcomes for their patients. Currently MA TKA remains the gold standard with good outcomes and excellent longevity. There is no published RCTs comparing FA to MA yet and only two registered studies are planned or currently in progress. This study utilizes a FA technique which differs from the two studies. This study will help determine if FA TKA has superior functional results for patients.Trial registration: This trial has been registered with the Australian New Zealand Clinical Trials Registry (ANZCTR) http://www.anzctr.org.au: U1111-1257-2291, registered 25th Jan 2021. It is also listed on www.clinicaltrials.gov: NCT04748510

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