scholarly journals In vivo three-dimensional kinematics of normal knees during different high-flexion activities

2018 ◽  
Vol 100-B (1) ◽  
pp. 50-55 ◽  
Author(s):  
K. Kono ◽  
T. Tomita ◽  
K. Futai ◽  
T. Yamazaki ◽  
S. Tanaka ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
External Rotation ◽  
Three Dimensional ◽  
Lateral Side ◽  
3D Registration ◽  
High Flexion ◽  
Valgus Angle ◽  
Significant Difference ◽  
Medial Pivot

Aims In Asia and the Middle-East, people often flex their knees deeply in order to perform activities of daily living. The purpose of this study was to investigate the 3D kinematics of normal knees during high-flexion activities. Our hypothesis was that the femorotibial rotation, varus-valgus angle, translations, and kinematic pathway of normal knees during high-flexion activities, varied according to activity. Materials and Methods We investigated the in vivo kinematics of eight normal knees in four male volunteers (mean age 41.8 years; 37 to 53) using 2D and 3D registration technique, and modelled the knees with a computer aided design program. Each subject squatted, kneeled, and sat cross-legged. We evaluated the femoral rotation and varus-valgus angle relative to the tibia and anteroposterior translation of the medial and lateral side, using the transepicodylar axis as our femoral reference relative to the perpendicular projection on to the tibial plateau. This method evaluates the femur medially from what has elsewhere been described as the extension facet centre, and differs from the method classically applied. Results During squatting and kneeling, the knees displayed femoral external rotation. When sitting cross-legged, femurs displayed internal rotation from 10° to 100°. From 100°, femoral external rotation was observed. No significant difference in varus-valgus angle was seen between squatting and kneeling, whereas a varus position was observed from 140° when sitting cross-legged. The measure kinematic pathway using our methodology found during squatting a medial pivoting pattern from 0° to 40° and bicondylar rollback from 40° to 150°. During kneeling, a medial pivot pattern was evident. When sitting cross-legged, a lateral pivot pattern was seen from 0° to 100°, and a medial pivot pattern beyond 100°. Conclusion The kinematics of normal knees during high flexion are variable according to activity. Nevertheless, our study was limited to a small number of male patients using a different technique to report the kinematics than previous publications. Accordingly, caution should be observed in generalizing our findings. Cite this article: Bone Joint J 2018;100-B:50–5.

In Vivo Three-dimensional Kinematics of Normal Knees During Sitting Sideways

2021 ◽  
Author(s):  
Kenichi Kono ◽  
Takaharu Yamazaki ◽  
Shoji Konda ◽  
Hiroshi Inui ◽  
Sakae Tanaka ◽  
...  
Keyword(s):  
External Rotation ◽  
Three Dimensional ◽  
Knee Kinematics ◽  
Lateral Side ◽  
Medial Side ◽  
Valgus Angle ◽  
Significant Movement ◽  
Anteroposterior Translation ◽  
Medial Pivot

Abstract Background The normal knee kinematics during asymmetrical kneeling such as the sitting sideways remains unknown. This study aimed to clarify in vivo kinematics during sitting sideways of normal knees. Methods Twelve knees from six volunteers were examined. Under fluoroscopy, each volunteer performed a sitting sideways. A two-dimensional/three-dimensional registration technique was used. The rotation angle, varus-valgus angle, anteroposterior translation of the medial and lateral sides of the femur relative to the tibia, and kinematic pathway in each flexion angle was evaluated. Results Bilateral knees during sitting sideways showed a femoral external rotation relative to the tibia with flexion. Whereas the ipsilateral knees showed valgus movement, and the contralateral knees showed varus movement. The medial side of the contralateral knees was more posteriorly located than that of the ipsilateral knees beyond 110° of flexion. The lateral side of the contralateral knees was more anteriorly located than that of the ipsilateral knees from 120° to 150° of flexion. In the ipsilateral knees, a medial pivot pattern followed by a bicondylar rollback was observed. In the contralateral knees, no significant movement followed by a bicondylar rollback was observed. Conclusion Even though the asymmetrical kneeling such as sitting sideways, the knees did not display asymmetrical movement.

scholarly journals Comparison between Novice and Experienced Surgeons Performing Corrective Osteotomy with Patient-Specific Guides in Dogs Based on Resulting Position Accuracy

2021 ◽  
Vol 8 (3) ◽  
pp. 40
Author(s):  
Yoon Ho Rho ◽  
Cheong Woon Cho ◽  
Chang Hun Ryu ◽  
Je Hun Lee ◽  
Seong Mok Jeong ◽  
...  
Keyword(s):  
Computer Aided Design ◽  
Corrective Osteotomy ◽  
Three Dimensional ◽  
Patient Specific ◽  
Bone Modeling ◽  
Accuracy Evaluation ◽  
3D Registration ◽  
Rotational Angle ◽  
Significant Difference ◽  
Angular Deformities

Corrective osteotomy has been applied to realign and stabilize the bones of dogs with lameness. However, corrective osteotomy for angular deformities requires substantial surgical experience for planning and performing accurate osteotomy. Three-dimensional printed patient-specific guides (3D-PSGs) were developed to overcome perioperative difficulties. In addition, novices can easily use these guides for performing accurate corrective osteotomy. We compared the postoperative results of corrective osteotomy accuracy when using 3D-PSGs in dogs between novice and experienced surgeons. We included eight dogs who underwent corrective osteotomy: three angular deformities of the radius and ulna, three distal femoral osteotomies, one center of rotational angle-based leveling osteotomy, and one corrective osteotomy with stifle arthrodesis. All processes, including 3D bone modeling, production of PSGs, and rehearsal surgery were carried out with computer-aided design software and a 3D-printed bone model. Pre- and postoperative positions following 3D reconstruction were evaluated by radiographs using the 2D/3D registration technique. All patients showed clinical improvement with satisfactory alignment and position. Postoperative accuracy evaluation revealed no significant difference between novice and experienced surgeons. PSGs are thought to be useful for novice surgeons to accurately perform corrective osteotomy in dogs without complications.

Development of Mucoadhesive Buccal Drug Delivery System of Propranolol Hydrochloride Using Aster ericoides Mucilage

2020 ◽  
Vol 10 (2) ◽  
pp. 133-148
Author(s):  
Ankaj Kaundal ◽  
Pravin Kumar ◽  
Rajendra Awasthi ◽  
Giriraj T. Kulkarni
Keyword(s):  
Buccal Cavity ◽  
Three Dimensional ◽  
Hot Water ◽  
Fickian Diffusion ◽  
Aster Ericoides ◽  
Dimensional Network ◽  
Buccal Tablet ◽  
Significant Difference ◽  
Volunteer Group

Aim: The study was aimed to develop mucoadhesive buccal tablets using Aster ericoides leaves mucilage. Background : Mucilages are naturally occurring high-molecular-weight polyuronides, which have been extensively studied for their application in different pharmaceutical dosage forms. Objective: The objective of the present research was to establish the mucilage isolated from the leaves of Aster ericoides as an excipient for the formulation of the mucoadhesive buccal tablet. Method: The mucilage was isolated from the leaves of Aster ericoides by maceration, precipitated with acetone and characterized. Tablets were prepared using wet granulation technique and evaluated for various official tests. Results: The mucilage was found to be non-toxic on A-431 and Vero cell lines. It was insoluble but swellable in cold and hot water. The results indicate that mucilage can form a three-dimensional network. The pH of the mucilage (6.82 ± 0.13) indicated that it might be non-irritant to the buccal cavity. The mucilage was found to be free from microbes. The release of drug was by Fickian diffusion. The in vivo buccal tablet acceptance was 80%. No significant difference between the diastolic blood pressure of standard and Aster tablets treated volunteer group was recorded. Conclusion: The mucilage was found to be non-toxic on A-431 and Vero cell lines. It was insoluble but swellable in cold and hot water. The results indicate that mucilage can form a three-dimensional network. The pH of the mucilage (6.82 ± 0.13) indicated that it might be non-irritant to the buccal cavity. The mucilage was found to be free from microbes. The release of drug was by Fickian diffusion. The in vivo buccal tablet acceptance was 80%. No significant difference between the diastolic blood pressure of standard and Aster tablets treated volunteer group was recorded. Other: However, to prove the potency of the polymer, in vivo bioavailability studies in human volunteers are needed along with chronic toxicity studies in suitable animal models.

scholarly journals An MRI-Based Patient-Specific Computational Framework for the Calculation of Range of Motion of Total Hip Replacements

2021 ◽  
Vol 11 (6) ◽  
pp. 2852
Author(s):  
Maeruan Kebbach ◽  
Christian Schulze ◽  
Christian Meyenburg ◽  
Daniel Kluess ◽  
Mevluet Sungu ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Internal Rotation ◽  
Computer Aided Design ◽  
External Rotation ◽  
Patient Specific ◽  
Computational Framework ◽  
Total Hip ◽  
Total Hip Replacements ◽  
Significant Difference ◽  
Hip Replacements

The calculation of range of motion (ROM) is a key factor during preoperative planning of total hip replacements (THR), to reduce the risk of impingement and dislocation of the artificial hip joint. To support the preoperative assessment of THR, a magnetic resonance imaging (MRI)-based computational framework was generated; this enabled the estimation of patient-specific ROM and type of impingement (bone-to-bone, implant-to-bone, and implant-to-implant) postoperatively, using a three-dimensional computer-aided design (CAD) to visualize typical clinical joint movements. Hence, patient-specific CAD models from 19 patients were generated from MRI scans and a conventional total hip system (Bicontact® hip stem and Plasmacup® SC acetabular cup with a ceramic-on-ceramic bearing) was implanted virtually. As a verification of the framework, the ROM was compared between preoperatively planned and the postoperatively reconstructed situations; this was derived based on postoperative radiographs (n = 6 patients) during different clinically relevant movements. The data analysis revealed there was no significant difference between preoperatively planned and postoperatively reconstructed ROM (∆ROM) of maximum flexion (∆ROM = 0°, p = 0.854) and internal rotation (∆ROM = 1.8°, p = 0.917). Contrarily, minor differences were observed for the ROM during maximum external rotation (∆ROM = 9°, p = 0.046). Impingement, of all three types, was in good agreement with the preoperatively planned and postoperatively reconstructed scenarios during all movements. The calculated ROM reached physiological levels during flexion and internal rotation movement; however, it exceeded physiological levels during external rotation. Patients, where implant-to-implant impingement was detected, reached higher ROMs than patients with bone-to-bone impingement. The proposed framework provides the capability to predict postoperative ROM of THRs.

scholarly journals Measurement of femoral posterior condylar offset and posterior tibial slope in normal knees based on 3D reconstruction

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Liangxiao Bao ◽  
Shengwei Rong ◽  
Zhanjun Shi ◽  
Jian Wang ◽  
Yang Zhang
Keyword(s):  
Three Dimensional ◽  
Surgical Techniques ◽  
Inverse Correlation ◽  
Tibial Slope ◽  
Posterior Tibial Slope ◽  
Lateral Side ◽  
Posterior Condylar Offset ◽  
Posterior Tibial ◽  
Significant Difference ◽  
Posterior Condylar

Abstract Background Femoral posterior condylar offset (PCO) and posterior tibial slope (PTS) are important for postoperative range of motion after total knee arthroplasty (TKA). However, normative data of PCO and PTS and the correlation between them among healthy populations remain to be elucidated. The purpose of this study was to determine PCO and PTS in normal knees, and to identify the correlation between them. Methods Eighty healthy volunteers were recruited. CT scans were performed followed by three-dimensional reconstruction. PCO and PTS were measured and analyzed, as well as the correlation between them. Results PTS averaged 6.78° and 6.11°, on the medial and lateral side respectively (P = 0.002). Medial PCO was greater than lateral (29.2 vs. 23.8 mm, P <  0.001). Both medial and lateral PCO of male were larger than female. On the contrary, male medial PTS was smaller than female, while there was no significant difference of lateral PTS between genders. There was an inverse correlation between medial PCO and PTS, but not lateral. Conclusions Significant differences exhibited between medial and lateral compartments, genders, and among individuals. An inverse correlation exists between PCO and PTS in the medial compartment. These results improve our understanding of the morphology and biomechanics of normal knees, and subsequently for optimising prosthetic design and surgical techniques.

scholarly journals Comparative Study of the Trueness of the Inner Surface of Crowns Fabricated from Three Types of Lithium Disilicate Blocks

2019 ◽  
Vol 9 (9) ◽  
pp. 1798 ◽  
Author(s):  
Son ◽  
Yu ◽  
Yoon ◽  
Lee
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
Lithium Disilicate ◽  
Correction Method ◽  
3D Analysis ◽  
Angular Region ◽  
Second Molar ◽  
Significant Difference ◽  
Inner Surface ◽  
Aided Design

This study set out to compare the three-dimensional (3D) trueness of crowns produced from three types of lithium disilicate blocks. The working model was digitized, and single crowns (maxillary left second molar) were designed using computer-aided design (CAD) software. To produce a crown design model (CDM), a crown design file was extracted from the CAD software. In addition, using the CDM file and a milling machine (N = 20), three types of lithium disilicate blocks (e.max CAD, HASS Rosetta, and VITA Suprinity) were processed. To produce a crown scan model (CSM), the inner surface of each fabricated crown was digitized using a touch-probe scanner. In addition, using 3D inspection software, the CDM was partitioned (into marginal, axis, angular, and occlusal regions), the CDM and CSM were overlapped, and a 3D analysis was conducted. A Kruskal–Wallis test (α = 0.05) was conducted with all-segmented teeth with the root mean square (RMS), and they were analyzed using the Mann–Whitney U-test and the Bonferroni correction method as a post hoc test. There was a significant difference in the trueness of the crowns according to the type of lithium disilicate block (p < 0.001). The overall RMS value was at a maximum for e.max (42.9 ± 4.4 µm), followed by HASS (30.1 ± 9.0 µm) and then VITA (27.3 ± 7.9 µm). However, there was no significant difference between HASS and VITA (p = 0.541). There were significant differences in all regions inside the crown (p < 0.001). There was a significantly high trueness in the angular region inside the crown (p < 0.001). A correction could thus be applied in the CAD process, considering the differences in the trueness by the type of lithium disilicate block. In addition, to attain a crown with an excellent fit, it is necessary to provide a larger setting space for the angular region during the CAD process.

scholarly journals Pressure Change Of Fixed Rotational Deformities In The Femur In Human Cadaver Knees-A Biomechanical Study

2020 ◽  
Author(s):  
Peizhi Yuwen ◽  
Hongzhi Lv ◽  
Yanbin Zhu ◽  
Wenli Chang ◽  
Ning Wei ◽  
...  
Keyword(s):  
Internal Rotation ◽  
Contact Pressure ◽  
Tibial Plateau ◽  
External Rotation ◽  
Pressure Change ◽  
Lateral Side ◽  
Neutral Position ◽  
Relative Pressure ◽  
Rotational Deformity ◽  
Significant Difference

Abstract Objective: To reveal the contact pressure change on tibial plateau in malalignment femur. Methods: Fourteen adult cadaver were selected, after autopsy, 14 cadaveric knee were established and fixed at neutral position (0°, anatomically reduced), 5°, 10°, 15° of external rotation, and 5°, 10°, 15° of internal rotation. Connect the rotatory fixation model on the biomechanical machine and apply a vertical load to 400N. The contact pressure on medial and lateral tibial plateau was quantitatively measured using ultra-low-pressure sensitive film technology. FPD-305E density meter and FPD-306E pressure converter were used to read relative pressure value. Data were analyzed using SPSS software. Results: The medial group show a significant difference on tibial plateau ( F =92.114, P <0.01), further test showed statistically significant differences of pairwise comparisons between 0°, 5°, 10°, 15° internal rotation deformity ( P <0.05). There is no significant difference in lateral group ( c 2 =9.967, P <0.01). The medial contact pressure is 0.940±0.177 MPa and the lateral is 1.008±0.219 MPa at neutral position, no statistically significant was found, so is 5° of internal rotational deformity. But the medial contact pressure are all higher than the lateral side at 5°, 10°, 15° of external rotation, and 10°, 15° of internal rotation. Conclusion: Obvious contact pressure changes on tibial plateau were observed in rotatory deformity femur, which is closely related to the occurrence of knee osteoarthritis. Doctors should detect rotational deformity as much as possible during operation and perform anatomical reduction, for patients with residual rotational deformities, indication of osteotomy should not be too broad.

scholarly journals Patient-specific resurfacing implant knee surgery in subjects with early osteoarthritis results in medial pivot and lateral femoral rollback during flexion: a retrospective pilot study

2021 ◽  
Author(s):  
Philippe Moewis ◽  
René Kaiser ◽  
Adam Trepczynski ◽  
Christoph von Tycowicz ◽  
Leonie Krahl ◽  
...  
Keyword(s):  
Knee Arthroplasty ◽  
External Rotation ◽  
Knee Kinematics ◽  
Axial Rotation ◽  
Patient Specific ◽  
Post Surgery ◽  
Flexion Extension ◽  
Medial Pivot ◽  
Femoral Rollback

Abstract Purpose Metallic resurfacing implants have been developed for the treatment of early, small, condylar and trochlear osteoarthritis (OA) lesions. They represent an option for patients who do not fulfill the criteria for unicompartmental knee arthroplasty (UKA) or total knee arthroplasty (TKA) or are too old for biological treatment. Although clinical evidence has been collected for different resurfacing types, the in vivo post-operative knee kinematics remain unknown. The present study aims to analyze the knee kinematics in subjects with patient-specific episealer implants. This study hypothesized that patient-specific resurfacing implants would lead to knee kinematics close to healthy knees, resulting in medial pivot and a high degree of femoral rollback during flexion. Methods Retrospective study design. Fluoroscopic analysis during unloaded flexion–extension and loaded lunge was conducted at > 12 months post-surgery in ten episealer knees, and compared to ten healthy knees. Pre- and post-operative clinical data of the episealer knees were collected using a visual analog scale (VAS), the EQ 5d Health, and the Knee Injury and Osteoarthritis Outcome Score (KOOS) questionnaires. Results A consistent medial pivot was observed in both episealer and healthy knees. Non-significant differences were found in the unloaded (p = 0.15) and loaded (p = 0.51) activities. Although lateral rollback was observed in both groups, it was significantly higher for the episealer knees in both the unloaded (p = 0.02) and loaded (p = 0.01) activities. Coupled axial rotation was significantly higher in the unloaded (p = 0.001) but not in the loaded (p = 0.06) activity in the episealer knees. Improved scores were observed at 1-year post-surgery in the episealer subjects for the VAS (p = 0.001), KOOS (p = 0.001) and EQ Health (p = 0.004). Conclusion At 12 month follow-up, a clear physiological knee kinematics pattern of medial pivot, lateral femoral rollback and coupled axial external femoral rotation during flexion was observed in patients treated with an episealer resurfacing procedure. However, higher femoral rollback and axial external rotation in comparison to healthy knees was observed, suggesting possible post-operative muscle weakness and consequent insufficient stabilization at high flexion.

scholarly journals In vivo length change of ligaments of normal knees during dynamic high flexion

2020 ◽  
Author(s):  
Kenichi Kono ◽  
Shoji Konda ◽  
Takaharu Yamazaki ◽  
Sakae Tanaka ◽  
Kazuomi Sugamoto ◽  
...  
Keyword(s):  
Medial Collateral Ligament ◽  
Sagittal Plane ◽  
Cruciate Ligament ◽  
Lateral Collateral Ligament ◽  
Length Change ◽  
3D Registration ◽  
Collateral Ligament ◽  
High Flexion ◽  
Leg Motion

Abstract Background Few studies compared the length change of ligaments of normal knees during dynamic activities of daily living. The aim of this study was to investigate in vivo length change of ligaments of the normal knees during high flexion. Methods Eight normal knees were investigated. Each volunteer performed squatting, kneeling, and cross-leg motions. Each sequential motion was performed under fluoroscopic surveillance in the sagittal plane. The femoral, tibial, and fibular attachment areas of the anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), deep medial collateral ligament (dMCL), superficial medial collateral ligament (sMCL), and lateral collateral ligament (LCL) were determined according to osseous landmarks. After 2D/3D registration, the direct distance from the femoral attachment to the tibial or fibular attachment was measured as the ligament length. Results From 20° to 90° with flexion, the ACL was significantly shorter during cross-leg motion than during squatting. For the PCL, dMCL, sMCL, and LCL, there were no significant differences among the 3 motions. Conclusion The ACL was shorter during cross-leg motion than during squatting in mid-flexion. This suggests that the ACL is looser during cross-leg motion than during squatting. On the other hand, the length change of the PCL, MCL, and LCL did not change even though the high flexion motions were different.

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