scholarly journals Lift-off reduction and patella tracking in Total Knee Arthroplasty (TKA) using a 3D printed patient-specific knee model

2021 ◽  
Author(s):  
Alexandra Mercader ◽  
Isabella Ostner ◽  
Freya Küppers ◽  
Tim C. Lueth ◽  
Heinz Röttinger ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Knee Flexion ◽  
External Rotation ◽  
Patient Specific ◽  
Tibiofemoral Joint ◽  
Cutting Method ◽  
3D Printed ◽  
Total Knee ◽  
Lift Off

Abstract The patellofemoral joint is greatly influenced by the geometry and position of the femur during knee flexion. After knee replacement surgery, the joint geometry is changed by the surface replacement and its kinematics by the orientation of the cutting planes planned by the surgeon. The technique presented in this study verifies the compatibility of the cutting method during total knee arthroplasty (TKA) with the geometry of the joint and the kinematics of knee flexion. To confirm the benefit of this method, three patient-specific knee models were printed in 3D. All models were made from the patient’s CT data and the patient’s measurement of flexion motion obtained with an infrared stereo camera. The models are operated according to three different techniques: Kinematic Alignment (KA), Measured Resection (MR) with 3 degrees of external rotation and MR with 9 degrees of external rotation. The resulting postoperative knees from the different alignment techniques are compared to the patient’s preoperative knee. The results show that the movement of the patella is modified after surgery on the model. The different alignments also lead to a variation in the behavior of the tibiofemoral joint. Based on these three examples, MR with an external orientation of the prosthesis results in a patellar movement closer to the preoperative movement. The KA method also reproduces the patella movement almost identically, but a lift-off appears at the tibiofemoral joint. The error observed for each cutting method between the pre-and postoperative patella position varies by a maximum of 5 degrees of rotation and 5 mm of translation, showing that the configuration has an overall small impact on the patellar movement. This study of three cases shows the importance of the preparation of the operation and the adjustment of the prosthesis for each specific patient using the 3D printed model.

scholarly journals Optimal Design of Patient-Specific Total Knee Arthroplasty for Improvement in Wear Performance

2019 ◽  
Vol 8 (11) ◽  
pp. 2023 ◽  
Author(s):  
Yong-Gon Koh ◽  
Kyung-Hwan Jung ◽  
Hyoung-Taek Hong ◽  
Kang-Min Kim ◽  
Kyoung-Tak Kang
Keyword(s):  
Total Knee Arthroplasty ◽  
Optimal Design ◽  
Knee Arthroplasty ◽  
External Rotation ◽  
Patient Specific ◽  
Fe Modelling ◽  
Wear Performance ◽  
Wear Rates ◽  
Tibial Insert ◽  
Total Knee

Life expectancy is on the rise and, concurrently, the demand for total knee arthroplasty (TKA), which lasts a lifetime, is increasing. To meet this demand, improved TKA designs have been introduced. Recent advances in radiography and manufacturing techniques have enabled the production of patient-specific TKA. Nevertheless, concerns regarding the wear performance, which limit the lifespan of TKA, remain to be addressed. This study aims at reducing the wear in patient-specific TKA using design optimization and parametric three-dimensional (3D) finite-element (FE) modelling. The femoral component design was implemented in a patient-specific manner, whereas the tibial insert conformity remained to be determined by design variables. The gait cycle loading condition was applied, and the optimized model was validated by the results obtained from the experimental wear tests. The wear predictions were iterated for five million gait cycles using the computational model with force-controlled input. Similar patterns for internal/external rotation and anterior/posterior translation were observed in both initial and optimal models. The wear rates for initial and optimal models were recorded as 23.2 mm3/million cycles and 16.7 mm3/million cycles, respectively. Moreover, the experimental wear rate in the optimal design was 17.8 mm3/million cycles, which validated our optimization procedure. This study suggests that tibial insert conformity is an important factor in influencing the wear performance of patient-specific TKA, and it is capable of providing improved clinical results through enhanced design selections. This finding can boost the future development of patient-specific TKA, and it can be extended to other joint-replacement designs. However, further research is required to explore the potential clinical benefits of the improved wear performance demonstrated in this study.

Changes in Tibiofemoral Joint Space Following Total Knee Arthroplasty During Weight-Bearing Knee Motion

2009 ◽  
Author(s):  
Kartik M. Varadarajan ◽  
Angela L. Moynihan ◽  
Jong Keun Seon ◽  
Andrew A. Freiberg ◽  
Harry E. Rubash ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Knee Flexion ◽  
Weight Bearing ◽  
Surgical Techniques ◽  
Joint Space ◽  
Extensor Mechanism ◽  
Implant Design ◽  
Tibiofemoral Joint ◽  
Total Knee

Increasing the range of knee flexion following total knee arthroplasty (TKA) remains an important objective for design of new implants and advancement of surgical techniques. With the excellent long term (10–15 year) outcome of TKA, surgeons are more confident about performing the procedure on younger, more active patients demanding increased range of knee flexion [1–3]. Numerous factors have been linked to limited flexion (<120°) following TKA, including patient factors such as preoperative range of motion, intraoperative factors such as component malposition, and implant design [1–3]. Extensor mechanism overstretching due to overstuffing of the knee joint is hypothesized to be a contributing factor limiting knee flexion [1–4]. However, no study to date has investigated the changes in tibiofemoral joint space following TKA. The aim of this study was to examine pre- and post-operative tibiofemoral joint space in a group of TKA patients during weight-bearing knee flexion and to compare it to that in the normal/healthy knee. This could help determine if changes in the proximal-distal distance between the femur and the tibia (tibiofemoral joint space) could lead to extensor mechanism overstretching and consequently limited range of flexion.

scholarly journals Accuracy of bone resection in total knee arthroplasty using CT assisted-3D printed patient specific cutting guides

SICOT-J ◽  
2018 ◽  
Vol 4 ◽  
pp. 29 ◽  
Author(s):  
Ikram Nizam ◽  
Ashish V. Batra
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Patient Specific ◽  
Surgical Patient ◽  
Bone Resection ◽  
Patient Specific Instrumentation ◽  
Medial Pivot ◽  
Cutting Guides ◽  
3D Printed ◽  
Total Knee

Introduction: We conducted this study to determine if the pre-surgical patient specific instrumented planning based on Computed Tomography (CT) scans can accurately predict each of the femoral and tibial resections performed through 3D printed cutting guides. The technique helps in optimization of component positioning determined by accurate bone resection and hence overall alignment thereby reducing errors. Methods: Prophecy evolution medial pivot patient specific instrumented knee replacement systems were used for end stage arthrosis in all consecutive cases over a period of 20 months by a single surgeon. All resections (4 femoral and 2 tibial) were measured using a vernier callipers intraoperatively. These respective measurements were then compared with the preoperative CT predicted bone resection surgical plan to determine margins of errors that were categorized into 7 groups (0 mm to ≥2.6 mm). Results: A total of 3618 measurements (averaged to 1206) were performed in 201 knees (105 right and 96 left) in 188 patients (112 females and 76 males) with an average age of 67.72 years (44 to 90 years) and average BMI of 32.3 (25.1 to 42.3). 94% of all collected resection readings were below the error margin of ≤1.5 mm of which 90% showed resection error of ≤1 mm. Mean error of different resections were ≤0.60 mm (P ≤ 0.0001). In 24% of measurements there were no errors or deviations from the templated resection (0.0 mm). Conclusion: The 3D printed cutting blocks with slots for jigs accurately predict bone resections in patient specific instrumentation total knee arthroplasty which would directly affect component positioning.

scholarly journals Effect of patellar tendon release on squatting characteristics of tibiofemoral joint after total knee arthroplasty: a simulation analysis

2020 ◽  
Author(s):  
Jian-ping Wang ◽  
Shihua Wang ◽  
Yongqiang Yang ◽  
Dong Guo ◽  
Jinlai Liu ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Patellar Tendon ◽  
Knee Arthroplasty ◽  
Simulation Analysis ◽  
External Rotation ◽  
Element Model ◽  
Tibiofemoral Joint ◽  
Human Knee Joint ◽  
No Release ◽  
Total Knee

Abstract BackgroundThe objective of this paper was to study the patellar tendon release’s effect on the squat movement characteristics of the tibiofemoral joint after TKA (total knee arthroplasty).MethodsThe dynamic FEM(finite element model) of the human knee joint with 30% release of the upper end, lower end and both ends of the patellar tendon after TKA was established respectively, and the knee tibiofemoral joint of the squat movement simulation analysis.ResultsThe results of simulation show that in the release of three different parts, comparing with the results of no release simulation, the average of lateral translation, superior translation, posterior translation, and the adduction of the femur relative to the tibia decreased by 20%, 17%, 17%, and 12%, respectively.ConclusionThe average of external rotation of the femur relative to the tibia increased 24%. By comparing the data after patellar tendon release and no release one, it can be concluded that the flexion degree of femur relative to the tibia was 4° on average more than no release. Moderate release of the patellar tendon during TKA surgery is beneficial to improve the range of motion (ROM) of the femur relative to the tibia.

scholarly journals The role of the femoral anterior offset index on the degree of flexion in total knee arthroplasty

2019 ◽  
Vol 5 (3) ◽  
pp. 376 ◽  
Author(s):  
João Maia Rosa ◽  
Marcio Oliveira ◽  
João Vide ◽  
Maria Miguel Carvalho ◽  
António Rodrigo Duarte ◽  
...  
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Knee Flexion ◽  
Patient Specific ◽  
Patient Specific Instrumentation ◽  
Negative Effect ◽  
Postoperative Flexion ◽  
Total Knee ◽  
Femoral Condyles

<p class="abstract"><strong>Background:</strong> Anterior projection of the femoral condyles is often disregarded as an issue in knee arthroplasty. Overstuffing the patellofemoral joint may limit knee flexion and be a source of patellofemoral complications, thus having an impact in satisfaction rates after total knee arthroplasty (TKA). Our hypothesis is that excessive anterior projection of the femoral condyles as a negative effect in flexion range after TKA, introducing a new concept, the anterior offset index (AOI).</p><p class="abstract"><strong>Methods:</strong> From a group of 99 consecutive patients who underwent TKA using patient specific instrumentation (PSI), we selected the patients with good pre-operative flexion range (above 90º) and a 6-minute walk test (6 MWT) ≥ 0 meters, evaluating the correlation between the AOI and the flexion range. A total of 23 patients were included in the study.<strong></strong></p><p class="abstract"><strong>Results:</strong> A moderate and positive correlation (r=0.488; p=0.018) between AOI and flexion range was found.</p><p class="abstract"><strong>Conclusions:</strong> Our results seem to indicate that the AOI influences postoperative flexion in TKA, in patients with a good pre-operative flexion and good functional outcome. AOI is an important concept to retain when optimizing knee flexion and minimizing patellofemoral complications. However, more studies need to be done in order to clarify the role of all the factors influencing post op flexion after TKA.</p>

scholarly journals Semi-constrained posterior stabilized total knee arthroplasty reproduces natural deep knee bending kinematics

2019 ◽  
Author(s):  
Takanobu Sumino ◽  
Tetsuya Tomita ◽  
Kazuomi Sugamoto ◽  
Takaharu Yamazaki ◽  
Ken Okazaki
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Knee Flexion ◽  
External Rotation ◽  
Weight Bearing ◽  
Posterior Stabilized ◽  
Anteroposterior Translation ◽  
Total Knee ◽  
Tibial Post ◽  
Roll Back

Abstract Background The Flexible Nichidai Knee Posterior Stabilized (FNK-PS) system was designed to provide relatively high varus-valgus stabilities without the stem extensions to patients with severe knee joint disorders. This is a combination of a large tibial post and high femoral cam adapted to a PS system. The aim of our study was to analyze the in vivo two-dimensional/three-dimensional registration kinematics of the FNK PS-total knee arthroplasty (TKA) system during deep knee bending.Methods Nineteen knees from 15 total knee arthroplasty (TKA) patients who were able to squat with enough knee flexion were selected. During deep knee bending under weight bearing (WB) and non-weight bearing (NWB) conditions, we quantified range of motion, axial rotation, femoral anteroposterior translation, and post-cam engagement angle.Results The maximum-flexion was significantly different between the two conditions. The mean axial femoral external rotation was 4.8° and 6.2° under WB and NWB conditions, respectively, at 120° flexion. Anteroposterior translation based on bicondylar posterior roll-back patterns was noted with increasing knee flexion. Both the medial and lateral femoral aspects were significantly more posterior during early to mid-flexion. Initial post-cam engagement occurred significantly earlier during flexion under NWB than under WB conditions. Under WB, the timing of the post-cam engagement correlated with the maximum flexion.Conclusions The kinematics of the semi-constrained PS system reproducibly exhibited a mild external rotation with smooth posterior roll-back, comparable to that of standard PS-TKAs. This was assisted by the engagement of the large tibial post and high femoral cam during the early phase of flexion.

Effect of Manipulation under Anesthesia of the First Knee in Staged Bilateral Total Knee Arthroplasty on Clinical Outcome and Satisfaction

2020 ◽  
Author(s):  
Jung-Won Lim ◽  
Yong-Beom Park ◽  
Dong-Hoon Lee ◽  
Han-Jun Lee
Keyword(s):  
Total Knee Arthroplasty ◽  
Patient Satisfaction ◽  
Clinical Outcome ◽  
Clinical Outcomes ◽  
Knee Arthroplasty ◽  
Knee Flexion ◽  
Functional Score ◽  
Manipulation Under Anesthesia ◽  
Total Knee

AbstractThis study aimed to evaluate whether manipulation under anesthesia (MUA) affect clinical outcome including range of motion (ROM) and patient satisfaction after total knee arthroplasty (TKA). It is hypothesized that MUA improves clinical outcomes and patient satisfaction after primary TKA. This retrospective study analyzed 97 patients who underwent staged bilateral primary TKA. MUA of knee flexion more than 120 degrees was performed a week after index surgery just before operation of the opposite site. The first knees with MUA were classified as the MUA group and the second knees without MUA as the control group. ROM, Knee Society Knee Score, Knee Society Functional Score, Western Ontario and McMaster Universities (WOMAC) score, and patient satisfaction were assessed. Postoperative flexion was significantly greater in the MUA group during 6 months follow-up (6 weeks: 111.6 vs. 99.8 degrees, p < 0.001; 3 months: 115.9 vs. 110.2 degrees, p = 0.001; 6 months: 120.2 vs. 117.0 degrees, p = 0.019). Clinical outcomes also showed similar results with knee flexion during 2 years follow-up. Patient satisfaction was significantly high in the MUA group during 12 months (3 months: 80.2 vs. 71.5, p < 0.001; 6 months: 85.8 vs. 79.8, p < 0.001; 12 months: 86.1 vs. 83.9, p < 0.001; 24 months: 86.6 vs. 85.5, p = 0.013). MUA yielded improvement of clinical outcomes including ROM, and patient satisfaction, especially in the early period after TKA. MUA in the first knee could be taken into account to obtain early recovery and to improve patient satisfaction in staged bilateral TKA.

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