scholarly journals The Insufficient Coverage of Lateral Trochlear Resection is Correlated to the Tibiofemoral Alignment Parameters in Kinematically Aligned TKA: A Retrospective Clinical Study

2020 ◽  
Author(s):  
Zhiwei Wang ◽  
Liang Wen ◽  
Liang Zhang ◽  
Desi Ma ◽  
Xiang Dong ◽  
...  
Keyword(s):  
Joint Line ◽  
Patient Specific ◽  
Bone Surface ◽  
Transepicondylar Axis ◽  
Tibiofemoral Joint ◽  
Joint Line Convergence Angle ◽  
Retrospective Clinical Study ◽  
Dependent Variables ◽  
Total Knee ◽  
Tibiofemoral Alignment

Abstract Background: The mismatching of the femoral component and trochlear resection surface is very common in kinematically aligned total knee arthroplasty (KA-TKA) when conventional prostheses are employed. This mismatching is mainly manifested in the insufficient coverage of the bone cut surface of the lateral trochlea. The aim of present study is to explore whether this mismatch is related to the alignment parameters of the tibiofemoral joint. Methods: 45 patients (52 knees) who underwent KA-TKA in our hospital were included. There were 16 patients (16 knees) received surgery using patient specific instrumentations, and conventional instruments with caliper and other special tools were employed in the other 29 patients (36 knees). The widths of exposed resection bone surface at the middle (MIDexposure) and distal (INFexposure) levels on the lateral trochlear were measured as dependent variables, while the hip-knee-ankle (HKA) angle, mechanical lateral distal femoral angle (mLDFA), joint line convergence angle (JLCA), medial proximal tibial angle (MPTA) and transepicondylar axis angle (TEAA) were measured as independent variables. Correlation analysis and subsequent linear regression were conducted among the dependent variables and various alignment parameters of the tibiofemoral joint. Results: The incidence of insufficient coverage of the lateral trochlear cut bone surface was 86.5%, with MIDexposure and INFexposure being 2.3 (0-6mm) and 2.0 (0-5mm), respectively. The widths of two levels of exposed bone resection were significantly correlated to mLDFA and HKA, but were not related to TEAA. Conclusions: the insufficient coverage of trochlear resection surface in KA-TKA is negatively correlated with the degrees of valgus of the distal femoral joint line and the degrees of varus of the knee. The present study suggest that in the development of KA-specific prostheses, attention should be paid to the effects of tibiofemoral alignment parameters on the prosthetic matching of the trochlear resection surface.

scholarly journals Undercoverage of lateral trochlear resection is correlated with the tibiofemoral alignment parameters in kinematically aligned TKA: a retrospective clinical study

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Zhiwei Wang ◽  
Liang Wen ◽  
Liang Zhang ◽  
Desi Ma ◽  
Xiang Dong ◽  
...  
Keyword(s):  
Joint Line ◽  
Patient Specific ◽  
Transepicondylar Axis ◽  
Tibiofemoral Joint ◽  
Patient Specific Instrumentation ◽  
Included Patient ◽  
Joint Line Convergence Angle ◽  
Retrospective Clinical Study ◽  
Dependent Variables ◽  
Total Knee

Abstract Background A mismatch between the femoral component and trochlear resection surface is observed in kinematically aligned total knee arthroplasty (KA-TKA) when conventional prostheses are employed. This mismatch is mainly manifested in the undercoverage of the lateral trochlear resection surface. The aim of the present study was to assess the relationship between the mismatch and the alignment parameters of the tibiofemoral joint. Methods Forty-five patients (52 knees) who underwent KA-TKA in our hospital were included. Patient-specific instrumentation was used in 16 patients (16 knees), and conventional instruments with calipers and other special tools were employed in the other 29 patients (36 knees). The widths of the exposed resection bone surface at the middle (MIDexposure) and distal (DISexposure) levels on the lateral trochlea were measured as dependent variables, whereas the hip-knee-ankle angle (HKAA), mechanical lateral distal femoral angle (mLDFA), joint line convergence angle (JLCA), medial proximal tibial angle (MPTA) and transepicondylar axis angle (TEAA) were measured as independent variables. Correlation analysis and subsequent linear regression were conducted among the dependent variables and various alignment parameters of the tibiofemoral joint. Results The incidence of undercoverage of the lateral trochlear resection surface was 86.5 % with MIDexposure and DISexposure values of 2.3 (0–6 mm) and 2.0 (0–5 mm), respectively. The widths of the two levels of exposed bone resection were significantly correlated with mLDFA and HKAA but were not related to TEAA. Conclusions The undercoverage of the trochlear resection surface in KA-TKA is mainly correlated with the degree of valgus of the distal femoral joint line. The current study suggests that this correlation should be considered in the development of KA-specific prostheses.

scholarly journals Accurate implant fit and leg alignment after cruciate-retaining patient-specific total knee arthroplasty

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Jörg Arnholdt ◽  
Yama Kamawal ◽  
Konstantin Horas ◽  
Boris M. Holzapfel ◽  
Fabian Gilbert ◽  
...  
Keyword(s):  
Knee Arthroplasty ◽  
Tibial Slope ◽  
Joint Line ◽  
Patient Specific ◽  
Cruciate Retaining ◽  
Custom Made ◽  
Ankle Angle ◽  
Total Knee ◽  
Replacement System ◽  
Hip Knee Ankle Angle

Abstract Background For improved outcomes in total knee arthroplasty (TKA) correct implant fitting and positioning are crucial. In order to facilitate a best possible implant fitting and positioning patient-specific systems have been developed. However, whether or not these systems allow for better implant fitting and positioning has yet to be elucidated. For this reason, the aim was to analyse the novel patient-specific cruciate retaining knee replacement system iTotal™ CR G2 that utilizes custom-made implants and instruments for its ability to facilitate accurate implant fitting and positioning including correction of the hip-knee-ankle angle (HKA). Methods We assessed radiographic results of 106 patients who were treated with the second generation of a patient-specific cruciate retaining knee arthroplasty using iTotal™ CR G2 (ConforMIS Inc.) for tricompartmental knee osteoarthritis (OA) using custom-made implants and instruments. The implant fit and positioning as well as the correction of the mechanical axis (hip-knee-ankle angle, HKA) and restoration of the joint line were determined using pre- and postoperative radiographic analyses. Results On average, HKA was corrected from 174.4° ± 4.6° preoperatively to 178.8° ± 2.2° postoperatively and the coronal femoro-tibial angle was adjusted on average 4.4°. The measured preoperative tibial slope was 5.3° ± 2.2° (mean +/− SD) and the average postoperative tibial slope was 4.7° ± 1.1° on lateral views. The joint line was well preserved with an average modified Insall-Salvati index of 1.66 ± 0.16 pre- and 1.67 ± 0.16 postoperatively. The overall accuracy of fit of implant components was decent with a measured medial overhang of more than 1 mm (1.33 mm ± 0.32 mm) in 4 cases only. Further, a lateral overhang of more than 1 mm (1.8 mm ± 0.63) (measured in the anterior-posterior radiographs) was observed in 11 cases, with none of the 106 patients showing femoral notching. Conclusion The patient-specific iTotal™ CR G2 total knee replacement system facilitated a proper fitting and positioning of the implant components. Moreover, a good restoration of the leg axis towards neutral alignment was achieved as planned. Nonetheless, further clinical follow-up studies are necessary to validate our findings and to determine the long-term impact of using this patient- specific system.

scholarly journals Three-dimensional preoperative planning in the weight-bearing state: validation and clinical evaluation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Tabitha Roth ◽  
Fabio Carrillo ◽  
Matthias Wieczorek ◽  
Giulia Ceschi ◽  
Hooman Esfandiari ◽  
...  
Keyword(s):  
Clinical Evaluation ◽  
Preoperative Planning ◽  
Mechanical Axis ◽  
Weight Bearing ◽  
3D Models ◽  
Joint Line ◽  
Patient Specific ◽  
Registration Accuracy ◽  
Convergence Angle ◽  
Joint Line Convergence Angle

Abstract Objectives 3D preoperative planning of lower limb osteotomies has become increasingly important in light of modern surgical technologies. However, 3D models are usually reconstructed from Computed Tomography data acquired in a non-weight-bearing posture and thus neglecting the positional variations introduced by weight-bearing. We developed a registration and planning pipeline that allows for 3D preoperative planning and subsequent 3D assessment of anatomical deformities in weight-bearing conditions. Methods An intensity-based algorithm was used to register CT scans with long-leg standing radiographs and subsequently transform patient-specific 3D models into a weight-bearing state. 3D measurement methods for the mechanical axis as well as the joint line convergence angle were developed. The pipeline was validated using a leg phantom. Furthermore, we evaluated our methods clinically by applying it to the radiological data from 59 patients. Results The registration accuracy was evaluated in 3D and showed a maximum translational and rotational error of 1.1 mm (mediolateral direction) and 1.2° (superior-inferior axis). Clinical evaluation proved feasibility on real patient data and resulted in significant differences for 3D measurements when the effects of weight-bearing were considered. Mean differences were 2.1 ± 1.7° and 2.0 ± 1.6° for the mechanical axis and the joint line convergence angle, respectively. 37.3 and 40.7% of the patients had differences of 2° or more in the mechanical axis or joint line convergence angle between weight-bearing and non-weight-bearing states. Conclusions Our presented approach provides a clinically feasible approach to preoperatively fuse 2D weight-bearing and 3D non-weight-bearing data in order to optimize the surgical correction.

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 Surgeon Dominated Design Can Improve the Accuracy of Patient-specific Instruments in Kinematically Aligned TKA

2020 ◽  
Author(s):  
Zhiwei Wang ◽  
Liang Wen ◽  
Liang Zhang ◽  
Desi Ma ◽  
Xiang Dong ◽  
...  
Keyword(s):  
Joint Line ◽  
Patient Specific ◽  
Group 14 ◽  
Bone Resection ◽  
Patient Specific Instrumentation ◽  
Improve Accuracy ◽  
Before And After ◽  
Patient Specific Instruments ◽  
Total Knee ◽  
Line P

Abstract Precise bone resection is mandatory for kinematically aligned total knee arthroplasty（KA-TKA). Patient-specific instrumentation (PSI) has been applied to improve the accuracy of bone resection in TKA for many years. The purpose of this study was to investigate whether surgeons’ domination in PSI design can improve accuracy in KA-TKA. A total of 24 patients (24 knees) who underwent KA-TKA in our institution were assigned into engineer designed PSI group (10 knees) and surgeon designed PSI group (14 knees). The bone resection discrepancies of every key facets were used to evaluate the accuracy of PSI in bone resection, while the absolute differences of joint line orientation before and after surgery were used to evaluate the accuracy of PSI in joint line restoration. The overall discrepancy of bone resection was reduced by surgeon designed PSI compared to engineer designed PSI by 0.33mm (P<0.001). Surgeon designed PSI could reduce the outliers in terms of relative discrepancies in bone resection as well. Moreover, surgeon designed PSI could significantly improve the accuracy of PSI in the restoration of the joint line (p=0.01). This study indicate that the dominance of surgeons in both PSI design and subsequent surgical operation should be emphasized in efforts to improve the accuracy of PSI.

Total Hospital Costs and Readmission Rate of Patient-Specific Instrument in Total Knee Arthroplasty Patients

2020 ◽  
Author(s):  
Stephen Thomas ◽  
Ankur Patel ◽  
Corey Patrick ◽  
Gary Delhougne
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Hospital Cost ◽  
Readmission Rate ◽  
Hospital Costs ◽  
Patient Specific ◽  
P Value ◽  
Total Hospital Cost ◽  
Total Hospital ◽  
Total Knee

AbstractDespite advancements in surgical technique and component design, implant loosening, stiffness, and instability remain leading causes of total knee arthroplasty (TKA) failure. Patient-specific instruments (PSI) aid in surgical precision and in implant positioning and ultimately reduce readmissions and revisions in TKA. The objective of the study was to evaluate total hospital cost and readmission rate at 30, 60, 90, and 365 days in PSI-guided TKA patients. We retrospectively reviewed patients who underwent a primary TKA for osteoarthritis from the Premier Perspective Database between 2014 and 2017 Q2. TKA with PSI patients were identified using appropriate keywords from billing records and compared against patients without PSI. Patients were excluded if they were < 21 years of age; outpatient hospital discharges; evidence of revision TKA; bilateral TKA in same discharge or different discharges. 1:1 propensity score matching was used to control patients, hospital, and clinical characteristics. Generalized Estimating Equation model with appropriate distribution and link function were used to estimate hospital related cost while logistic regression models were used to estimate 30, 60, and 90 days and 1-year readmission rate. The study matched 3,358 TKAs with PSI with TKA without PSI patients. Mean total hospital costs were statistically significantly (p < 0.0001) lower for TKA with PSI ($14,910; 95% confidence interval [CI]: $14,735–$15,087) than TKA without PSI patients ($16,018; 95% CI: $15,826–$16,212). TKA with PSI patients were 31% (odds ratio [OR]: 0.69; 95% CI: 0.51–0.95; p-value = 0.0218) less likely to be readmitted at 30 days; 35% (OR: 0.65; 95% CI: 0.50–0.86; p-value = 0.0022) less likely to be readmitted at 60 days; 32% (OR: 0.68; 95% CI: 0.53–0.88; p-value = 0.0031) less likely to be readmitted at 90 days; 28% (OR: 0.72; 95% CI: 0.60–0.86; p-value = 0.0004) less likely to be readmitted at 365 days than TKA without PSI patients. Hospitals and health care professionals can use retrospective real-world data to make informed decisions on using PSI to reduce hospital cost and readmission rate, and improve outcomes in TKA patients.

MRI is more accurate than CT for patient-specific total knee arthroplasty

The Knee ◽  
2015 ◽  
Vol 22 (6) ◽  
pp. 609-612 ◽  
Author(s):  
Benjamin M. Frye ◽  
Amjad A. Najim ◽  
Joanne B. Adams ◽  
Keith R. Berend ◽  
Adolph V. Lombardi
Keyword(s):  
Total Knee Arthroplasty ◽  
Knee Arthroplasty ◽  
Patient Specific ◽  
Total Knee
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