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

2021 ◽  
Author(s):  
Peizhi Yuwen ◽  
Hongzhi Lv ◽  
Yanbin Zhu ◽  
Wenli Chang ◽  
Ning Wei ◽  
...  
Keyword(s):  
Internal Rotation ◽  
Contact Pressure ◽  
Tibial Plateau ◽  
Pressure Change ◽  
Lower Limbs ◽  
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 cadaveric Lower limbs were selected and autopsied, rotatory fixation model with different angles were then made. Connect each model on the biomechanical machine and apply a vertical load to 400N. The contact pressure 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 values. Contact pressure on medial and lateral tibial plateau in different femoral rotational deformities were compared. Analysis were done 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 (c2=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 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 Pressure Change Of Fixed Rotational Deformities In The Femur In Human Cadaver Knees-A Biomechanical Study

2021 ◽  
Author(s):  
Yuwen Peizhi ◽  
Hongzhi Lv ◽  
Yanbin Zhu ◽  
Wenli Chang ◽  
Ning Wei ◽  
...  
Keyword(s):  
Knee Joint ◽  
Internal Rotation ◽  
Contact Pressure ◽  
Tibial Plateau ◽  
Lower Limbs ◽  
Lateral Side ◽  
Neutral Position ◽  
Relative Pressure ◽  
Rotational Deformity ◽  
Significant Difference

Abstract Background: Closed intramedullary interlocking nailing is a standard treatment for femoral shaft fractures, but incidences of rotational malalignment after operation is really high. Poor reduction and postoperative malunion lead to many clinical symptoms and long term degenerative arthritis. It has been proved that uneven stress is the mechanical cause of knee joint degeneration, but few studies pay attention to the effect of femur rotational deformity on knee joint contact pressure.This study aim to quantitatively evaluate the relation between residual rotational deformity in femur and contact pressure of knee joint. Methods: Fourteen cadaveric Lower limbs were selected and autopsied, rotatory fixation model with different angles were then made. Connect each model on the biomechanical machine and apply a vertical load to 400N. The contact pressure 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 values. Contact pressure on medial and lateral tibial plateau in different femoral rotational deformities were compared. Analysis were done 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 (ꭓ2=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.

Strain in the Lateral Ligaments of the Ankle

Foot & Ankle ◽  
1988 ◽  
Vol 9 (2) ◽  
pp. 59-63 ◽  
Author(s):  
P. Renstrom ◽  
M. Wertz ◽  
S. Incavo ◽  
M. Pope ◽  
H.C. Ostgaard ◽  
...  
Keyword(s):  
Internal Rotation ◽  
External Rotation ◽  
Anterior Talofibular Ligament ◽  
Neutral Position ◽  
Calcaneofibular Ligament ◽  
Ankle Ligaments ◽  
Significant Difference ◽  
Ligament Strain ◽  
Pronation External Rotation ◽  
Relaxing Effect

Strain was measured in the normal anterior talofibular ligament (ATF) and the calcaneofibular ligament (CF) using Hall effect strain transducers in five cadaveric ankles. These measurements were made in both ligaments with the ankle in neutral position and with the foot moving from 10° dorsiflexion to 40° plantarflexion in an apparatus that permits physiologic motion. The ankle ligaments were then tested with the foot placed in six different positions that combined supination, pronation, external rotation, and internal rotation. In the neutral position, through a range of motion of 10° dorsiflexion to 40° plantarflexion, the anterior talofibular ligament underwent an increasing strain of 3.3%. No significant strain increase was found with internal rotation. The only significant difference from the strains at the neutral position was in external rotation, which decreased strain 1.9%. In all positions, increased strain occurred with increased plantarflexion. The calcaneofibular ligament was essentially isometric in the neutral position throughout the flexion arc. The calcaneofibular ligament strain was significantly increased by supination and external rotation. However, with increasing plantarflexion in these positions, the strain in the calcaneofibular ligament decreased. Therefore, plantarflexion has a relaxing effect on the calcaneofibular ligament. Thus, the anterior talofibular and calcaneofibular ligaments are synergistic, such that when one ligament is relaxed, the other is strained and vice versa.

scholarly journals Stiffness of the Gastrocnemius–Achilles Tendon Complex Between Amateur Basketball Players and the Non-athletic General Population

2020 ◽  
Vol 11 ◽  
Author(s):  
Tian-Tian Chang ◽  
Zhe Li ◽  
Xue-Qiang Wang ◽  
Zhi-Jie Zhang
Keyword(s):  
General Population ◽  
Achilles Tendon ◽  
Ankle Joint ◽  
Healthy Subjects ◽  
Lower Limbs ◽  
Medial Gastrocnemius ◽  
Neutral Position ◽  
Basketball Players ◽  
Significant Difference ◽  
Repeated Training

Muscle and tendon stiffness are related to sports performance, tendinopathy, and tendon degeneration. However, the effects of habitual loading on muscle and tendon mechanical properties are unclear. Using amateur basketball players as examples, we investigated the effects of mechanical loading on the stiffness of the gastrocnemius–Achilles tendon (AT) complex in non-dominant and dominant lower limbs. Then, we evaluated the correlation between gastrocnemius and AT stiffness. Forty participants (20 amateur basketball players; 20 normal non-athletic persons) were recruited for this study. Stiffness of the gastrocnemius–AT complex was assessed using MyotonPRO at neutral position and 10° dorsiflexion of the ankle joint in participants from amateur basketball players and the non-athletic general population. Our results showed a greater stiffness of the gastrocnemius–AT complex in amateur basketball players than that in healthy non-athletic subjects at neutral position and 10° dorsiflexion of the ankle joint (P &lt; 0.05). No significant difference in stiffness was found between the non-dominant and dominant lower limbs either in amateur basketball players or in generally healthy subjects (P &gt; 0.05). A significant positive correlation was obtained between stiffness of the AT and medial gastrocnemius (MG) in amateur basketball players (neutral position: r = 0.726 and P = 0.001; dorsiflexion 10°: r = 0.687 and P = 0.001). The amateur basketball players exhibit significantly higher stiffness value in Achilles and gastrocnemius. This is possibly caused by repeated training effects. The symmetric stiffness of the AT and gastrocnemius exists both in amateur basketball players and generally healthy subjects. A significant correlation between the AT and the MG was found in amateur basketball players.

scholarly journals A Quantifiable Risk Factor for ACL Injury: Applied Mathematics to Model the Posterolateral Tibial Plateau Surface Geometry

2021 ◽  
Vol 9 (4) ◽  
pp. 232596712199831
Author(s):  
Jimmy Tat ◽  
Drew Crapser ◽  
Motaz Alaqeel ◽  
Justin Schupbach ◽  
Jacob Lee-Howes ◽  
...  
Keyword(s):  
Internal Rotation ◽  
Tibial Plateau ◽  
Applied Mathematics ◽  
Femoral Condyle ◽  
Cruciate Ligament ◽  
Acl Injury ◽  
Surface Geometry ◽  
Lateral Tibial Plateau ◽  
Acl Injuries ◽  
Significant Difference

Background: The mechanism for traumatic ruptures of the native anterior cruciate ligament (ACL) is frequently a noncontact injury involving a valgus moment with internal rotation of the tibia. The abnormal rotation and translation of the lateral femoral condyle posteroinferiorly relative to the lateral tibial plateau is thought to be related to the geometry of the tibial plateau. Purpose/Hypothesis: The purpose of the study was to mathematically model the posterior tibial plateau geometry in patients with ACL injuries and compare it with that of matched controls. The hypothesis was that increased convexity and steepness of the posterior aspect of the lateral plateau would subject knees to higher forces, leading to a potentially higher risk of ACL injury. Study Design: Cross-sectional study; Level of evidence, 3. Methods: We mathematically modeled the posterior curvature of the lateral tibial plateau in 64 patients with ACL injuries and 68 matched controls. Using sagittal magnetic resonance imaging scans of the knee, points on the articular cartilage of the posterolateral tibial plateau were selected and curve-fitted to a power function ( y = a × xn). For coefficient a and coefficient n, both variables modulated the shape of the curve, where a larger magnitude represented an increase in slope steepness. Groups were compared using a Mann-Whitney test and α < .05. Results: There was a significant difference in surface geometry between the patients with ACL injuries and matched controls. The equation coefficients were significantly larger in the patients with ACL injuries: coefficient a (ACL injury, 0.9 vs control, 0.68; P < .0001) and coefficient n (ACL injury, 0.34 vs control, 0.30; P = .07). For coefficient a, there was a 78.9% sensitivity, 77.5% specificity, and odds ratio of 12.6 (95% CI, 5.5-29.0) for ACL injury using a cutoff coefficient a = .78. Conclusion: Patients with ACL injuries had a significantly greater posterolateral plateau slope. The steeper drop off may play a role in higher anterior translation forces, coupled with internal rotation torques on the knee in noncontact injury, which could increase ACL strain and predispose to ACL injury.

scholarly journals Biomechanical study on the stress distribution of the knee joint after residual rotation deformity of tibial fracture

2020 ◽  
Author(s):  
Ming Li ◽  
Yanbin Zhu ◽  
Ning Wei ◽  
Wenli Chang ◽  
Zeyue Jin ◽  
...  
Keyword(s):  
Stress Distribution ◽  
Knee Joint ◽  
Lower Limb ◽  
External Rotation ◽  
Biomechanical Study ◽  
Lower Limbs ◽  
Neutral Position ◽  
Lateral Stress ◽  
Significant Difference ◽  
The Difference

Abstract Objectives To investigate the effect of residual rotation deformity on the stress distribution of the knee joint after surgery to treat middle and upper tibial fractures. Methods Fourteen adult cadaver specimens that were preserved with formalin were included, and the tibias were randomly positioned at 0 degree, 5 degrees, 10 degrees, and 15 degrees from the line of force of the lower limb. These positions modeled deformities of 5 degrees, 10 degrees, and 15 degrees from the line of force. Low-pressure pressure-sensitive film technology measured the stress distribution of the knee joint under different degrees of rotation deformity. Results Under a vertical load of 400 N, the difference between the medial and lateral stress of the knee joint was significantly different between the different tibia deformities (P<0.05), and the medial stress of the knee joint was higher than the lateral stress. The current study showed that there were statistically significant differences in the medial stress on the knee joint at all angles (including the neutral position of 0 degrees) (F=89.753, P<0.001) . There was a statistically significant difference in the lateral stresses of the knee joint between different rotation deformities (including the neutral position of 0 degrees) (F=102.998, P<0.001). Conclusions Residual rotation deformity after fracture of middle and upper tibia can lead to poor alignment of lower limb force and change of articular contact characteristics of knee joint, especially external rotation of tibia.Therefore, orthopedic surgeons should correct the malalignment of lower limbs to the greatest extent and reduce the rotation deformity as far as possible.

scholarly journals Biomechanical Study of Screw Fixation and Plate Fixation of a Posterior Malleolar Fracture in Osteoporosis

2017 ◽  
Vol 2 (3) ◽  
pp. 2473011417S0004
Author(s):  
Xu Wang
Keyword(s):  
Gait Cycle ◽  
Plantar Flexion ◽  
Lower Limbs ◽  
Neutral Position ◽  
Motion System ◽  
Posterior Malleolus ◽  
Significant Difference ◽  
Space Motion ◽  
Group A ◽  
Group B

Category: Ankle, Trauma Introduction/Purpose: Purpose of this research is to biomechanically compare the screw-fixed and plate-fixed posterior malleolus fracture in osteoporosis patients with fatigue loading system and space motion system in simulation gait cycle. And to give a theory evidence on how to choose a internal fixation in osteoporosis patients with posterior malleolus fracture. Methods: 36 matched cadaveric pairs lower limbs (T＜-2.5) were prepared to simulate Haraguchi I posterior malleolus fracture and randomized into two groups. Models of group A were fixed with two paralleled 4.0 mm titanium partial thread cancellous screws from posterior to anterior. Models of group B were fixed with plate. Furthermore, 4 different conditions of gait cycle were simulated as follows:1. specimen was loaded with 3.2 body weight (BW) at dorsiflexion angle of 12°; 2. Start-up phase: dorsiflexion angle of 5°,3.6 BW; 3. neutral position,3.6 BW; 4. maximum plantar flexion, angle of 12°,4.5 BW. At the end of repeatedly, loading, the displacement of fracture fragment (X) was measureed with space motion system. Results: At 12°of dorsiflexion and 15°of plantar flexion, there was a significant difference of X between A and B group, no matter the S and H. When ankle was dorsiflexion of 5°, X of group A was more great than that of group B except A3a /B3a and A1b/B1b. At neutral positon, there was significant differenceof X in all the groups except group A2b and B2b. Conclusion: Compared with 2 paralleled 4.0 mm calcaneus screws from posterior to anterior, plate can provide stronger fixation for osteoporosis patients with posterior malleolus fracture. But both of the two methods cannot provide stable fixation for osteoporosis patients with posterior malleolus fragment S>1/3 and H>19.3 mm.

scholarly journals Lateral tenodesis procedures increase lateral compartment pressures more than anterolateral ligament reconstruction, when performed in combination with ACL reconstruction: a pilot biomechanical study

2020 ◽  
pp. jisakos-2019-000368
Author(s):  
Thomas Neri ◽  
Joseph Cadman ◽  
Aaron Beach ◽  
Samuel Grasso ◽  
Danè Dabirrahmani ◽  
...  
Keyword(s):  
Pilot Study ◽  
Contact Pressure ◽  
Ligament Reconstruction ◽  
Biomechanical Study ◽  
Anterolateral Ligament ◽  
Lower Limbs ◽  
Anterolateral Ligament Reconstruction ◽  
Significant Difference ◽  
Compartment Pressures ◽  
Contact Pressures

ObjectivesGiven the common occurrence of residual laxity and re-injury post anterior cruciate ligament reconstruction (ACLR), additional anterolateral procedures are increasingly used in combination with an ACLR. Despite the perception that there is a risk of over-constraining the lateral tibiofemoral (LTF) compartment, potentially leading to osteoarthritis, assessment on their effect on intra-articular compartment pressures is still lacking. Our objective was therefore, through a pilot biomechanical study, to compare LTF contact pressures after the most commonly used anterolateral procedures.MethodsA controlled laboratory pilot study was performed using 4 fresh-frozen cadaveric whole lower limbs. Through 0° to 90° of flexion, LTF contact pressures were measured with a Tekscan sensor, located under the lateral meniscus. Knee kinematics were obtained in 3 conditions of rotation (NR: neutral, ER: external and IR: internal rotation) to record the position of the knees for each loading condition. A Motion Analysis system with a coordinate system based on CT scans 3D bone modelling was used. After an ACLR, defined as the reference baseline, 5 anterolateral procedures were compared: anterolateral ligament reconstruction (ALLR), modified Ellison, deep Lemaire, superficial Lemaire and modified MacIntosh procedures. The last 3 procedures were randomised. For each procedure, the graft was fixed in NR at 30° of flexion and with a tension of 20 N.ResultsCompared with isolated ACLR, addition of either ALLR or modified Ellison procedure did not increased the overall LTF contact pressure (all p>0.05) through the full range of flexion for the IR condition. Conversely, deep Lemaire, superficial Lemaire and modified MacIntosh procedure (all p<0.05) did increase the overall LTF contact pressure compared with ACLR in IR. No significant difference was observed in ER and NR conditions.ConclusionThis pilot study, comparing the main anterolateral procedures, revealed that addition of either ALLR or modified Ellison procedure did not change the overall contact pressure in the LTF compartment through 0° to 90° of knee flexion. In contrast, the deep and superficial Lemaire, and modified MacIntosh procedures significantly increased overall LTF contact pressures when the knee was internally rotated.

scholarly journals Prediction accuracy of standard and total keratometry by swept-source optical biometer for multifocal intraocular lens power calculation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Hun Lee ◽  
Jae Lim Chung ◽  
Young Jun Kim ◽  
Jae Yong Kim ◽  
Hungwon Tchah
Keyword(s):  
Cataract Surgery ◽  
Case Series ◽  
Intraocular Lenses ◽  
Power Calculation ◽  
Neutral Position ◽  
Swept Source ◽  
Refractive Outcomes ◽  
Case Series Study ◽  
Significant Difference ◽  
Optical Biometer

AbstractWe aimed to compare the refractive outcomes of cataract surgery with diffractive multifocal intraocular lenses (IOLs) using standard keratometry (K) and total keratometry (TK). In this retrospective observational case series study, a total of 302 patients who underwent cataract surgery with multifocal IOL implantation were included. Predicted refractive outcomes were calculated based on the current standard formulas and a new formula developed for TK using K and TK, which were obtained from a swept-source optical biometer. At 2-month postoperatively, median absolute prediction errors (MedAEs) and proportion of eyes within ± 0.50 diopters (D) of predicted postoperative spherical equivalent (SE) refraction were analyzed. There was no significant difference between MedAEs or proportion of eyes within ± 0.50D of predicted refraction from K and TK in each formula. In TFNT00 and 839MP IOL cases, there was no difference between MedAEs from K and TK using any formula. In 829MP IOL cases, MedAE from TK was significantly larger than that from K in Barrett Universal II/Barrett TK Universal II (P = 0.033). In 677MY IOL cases, MedAE from TK was significantly larger than that from K in Haigis (P = 0.020) and Holladay 2 (P = 0.006) formulas. In the subgroup analysis for IOL, there was no difference between the proportion of eyes within ± 0.50 D of predicted refraction from K and TK using any formula. TFNT00 and 839MP IOLs were favorable with TK, with 677MY IOL with K and 829MP IOL being in a neutral position, which necessitates the study that investigates the accuracy of the new TK technology.

Computed tomography angiography and microsurgical flaps for traumatic wounds: What is the added value?

2021 ◽  
pp. 1-9
Author(s):  
Lucas Sousa Macedo ◽  
Renato Polese Rusig ◽  
Gustavo Bersani Silva ◽  
Alvaro Baik Cho ◽  
Teng Hsiang Wei ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Upper Limb ◽  
Computed Tomography Angiography ◽  
Lower Limb ◽  
High Energy ◽  
Lower Limbs ◽  
Added Value ◽  
Vascular Lesions ◽  
Limb Injuries ◽  
Significant Difference

BACKGROUND: Microsurgical flaps are widely used to treat complex traumatic wounds of upper and lower limbs. Few studies have evaluated whether the vascular changes in preoperative computed tomography angiography (CTA) influence the selection of recipient vessel and type of anastomosis and the microsurgical flaps outcomes including complications. OBJECTIVE: The aim of this study was to evaluate if preoperative CTA reduces the occurrence of major complications (revision of the anastomosis, partial or total flap failure, and amputation) of the flaps in upper and lower limb trauma, and to describe and analyze the vascular lesions of the group with CTA and its relationship with complications. METHODS: A retrospective cohort study was undertaken with all 121 consecutive patients submitted to microsurgical flaps for traumatic lower and upper limb, from 2014 to 2020. Patients were divided into two groups: patients with preoperative CTA (CTA+) and patients not submitted to CTA (CTA–). The presence of postoperative complications was assessed and, within CTA+, we also analyzed the number of patent arteries on CTA and described the arterial lesions. RESULTS: Of the 121 flaps evaluated (84 in the lower limb and 37 in the upper limb), 64 patients underwent preoperative CTA. In the CTA+ group, 56% of patients with free flaps for lower limb had complete occlusion of one artery. CTA+ patients had a higher rate of complications (p = 0.031), which may represent a selection bias as the most complex limb injuries and may have CTA indicated more frequently. The highest rate of complications was observed in chronic cases (p = 0.034). There was no statistically significant difference in complications in patients with preoperative vascular injury or the number of patent arteries. CONCLUSIONS: CTA should not be performed routinely, however, CTA may help in surgical planning, especially in complex cases of high-energy and chronic cases, since it provides information on the best recipient artery and the adequate level to perform the microanastomosis, outside the lesion area.

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