scholarly journals Passive ligament stability in natural knee: a cadaveric biomechanical study

10.29007/jp61 ◽  
2020 ◽  
Author(s):  
Thomas Paszicsnyek ◽  
Edoardo Bori ◽  
Bernardo Innocenti
Keyword(s):  
Knee Joint ◽  
Biomechanical Study ◽  
Cruciate Ligaments ◽  
Recent Experimental Study ◽  
Ligament Tension ◽  
The Stability ◽  
The One ◽  
Force Displacement ◽  
Cadaveric Knee

Objectives: Applying the correct amount of collateral ligaments tension in the knees during surgery is a prerequisite to restore normal kinematics after TKA. It is well known that a low value of ligament tension could lead to an instable joint while a higher tension could induce over-tensioning and problems at later follow-up. In this study, an experimental cadaveric activity was performed to measure the minimum tension required to achieve stability in the knee joint.Methods: 10 cadaveric knee specimens were investigated in this study. The femur and tibia were fixed with polyurethane foam in specific designed fixtures and clamped to a loading frame.Increasing displacement was applied to the femoral clamp and the relative force was measured by a loading-frame machine up to the stability of the joint, determined by a decrease in the derivate of the force/displacement trend followed by a plateau.The force span between the slack region and the plateau was considered as the tension required to stabilize the joint.This methodology was applied for joints with intact cruciate ligaments, after ACL resection and after further PCL resection, to simulate the knee behavior prior a CR and a PS implant.The test was performed at 0, 30, 60 and 90° of flexion. Each configuration was analyzed three times for the sake of repeatability.Results and Conclusion: Results demonstrated that an overall tension of 41.2N (range 30.0-48.0 N) is sufficient to reach stability in a native knee with intact cruciate ligaments. Similar values appear to be sufficient also in an ACL resected knee (average 45.6, range 41.2-50.0 N), while higher tension is required (average 58.6N, range 40.0-77.0 N) were necessary in the case of PCL retention. Moreover, in this configuration, the tension required for stabilization was slighter higher at 30 and 60° of flexion compared to the one required at 0 and 90° of flexion.The results are in agreement to the ones found by other recent experimental study [Manning et al 2018 (KSSTA)] and shown that the tension necessary to stabilize a knee joint in different ligament conditions is way lower than the ones usually applied via tensioners nowadays.To reach functional stability, surgeons need to consider such results intraoperatively to avoid laxity, mid-flexion instability or ligament over-tension.

The role of the posterolateral and cruciate ligaments in the stability of the human knee. A biomechanical study.

1987 ◽  
Vol 69 (2) ◽  
pp. 233-242 ◽  
Author(s):  
D L Gollehon ◽  
P A Torzilli ◽  
R F Warren
Keyword(s):  
Biomechanical Study ◽  
Cruciate Ligaments ◽  
Human Knee ◽  
The Stability

Electrochemical reduction of 2,2'-dinitrodiphenylmethane and 2,2'-dinitrobenzophenone at mercury electrodes

1983 ◽  
Vol 48 (2) ◽  
pp. 364-378 ◽  
Author(s):  
Rolf Voigtländer ◽  
Jaromír Hlavatý ◽  
Jiří Volke ◽  
Viktor Bakos
Keyword(s):  
Nitro Group ◽  
Supporting Electrolyte ◽  
Standard Addition ◽  
The Other ◽  
Anodic Wave ◽  
Mercury Electrodes ◽  
Electron Reduction ◽  
The Stability ◽  
The One

The last two compounds in a 5-membered series of aromatic dinitro compounds are reduced in a completely different manner at mercury electrodes. 2,2'-Dinitrodiphenylmethane (I) - in which a conjugation of both symmetrical moieties is ruled out - is electrolytically reduced in an eight-electron step to a bishydroxylamine this being most stable between pH 4.5 and 5.0. In processing the catholyte increase in concentration of this product leads to its intermolecular disproportionation, resulting in the formation of dibenzo[b, e]-1,2-diazepine 5-oxide (IV) and 2,2'-diaminodiphenylmethane (III). 2,2'-Dinitrobenzophenone (II) reduces at more positive potentials. Its preparative electrolysis in acetonitrile (with 0.1M-N(n-C4H9)4PF6 as supporting electrolyte) the application of which was made necessary by the low solubility of II in ethanol, proceeding in an anomalous way. In the most positive cathodic wave a radical anion results, the following cathodic wave corresponds to a 6-electron reduction of the one nitro group to an amino group while the other nitro group splits off as the anion NO-2 (this later giving an anodic wave). Its formation has been proved by standard addition in polarography and by a qualitative analytical test. The product which results through this electrode process and a follow-up chemical reaction is acridone. This in turn, reduces in the third, most negative 4-electron wave to dihydroacridine. The comparison of all substances studied in this series reveals that their reducibility decreases with respect to the link X, viz. in the sequence CO > O > S and CH2 > NH. The electrolytical reduction on mercury cathodes occurs in a similar manner with analogues where X = O, S or CH2. Here, the main intermediate is the bis-hydroxylamine the stability of which predetermines the structure of final products. The other group comprises the substances with X = CO and NH. Here the main intermediate is the 2-nitro-2'-amino-diphenyl-X which is formed in a 6-electron process taking place at one of the nitro groups. The follow-up cyclization reaction leading to seven-membered heterocyclic rings located between two benzene nuclei only occurs with analogues of the type X = CH2, O and S. A partial reduction of dinitro compounds of this series has been observed with the analogue containing the NH link although that with X = CO has generally good preconditions for this mechanism.

scholarly journals Arthroscopic Reconstruction of Anterior Cruciate Ligaments With Allograft: Single-tunnel Double-bundle Versus Single-tunnel Single-bundle

2020 ◽  
Author(s):  
Weimin Zhu ◽  
Yuanhui Zhou ◽  
Kang Chen ◽  
Yizi Zheng ◽  
Wei Lu ◽  
...  
Keyword(s):  
Knee Joint ◽  
Acl Reconstruction ◽  
Pivot Shift ◽  
Double Bundle ◽  
Pivot Shift Test ◽  
Single Bundle ◽  
Arthroscopic Reconstruction ◽  
Anterior Cruciate ◽  
The Stability

Abstract Purpose Arthroscopic reconstruction of anterior cruciate ligament (ACL) commonly adopted single-tunnel single-bundle (STSB) or double-tunnel double-bundle (DTDB) methods. Though single-tunnel double-bundle (STDB) has been used in clinical practice, the efficacy remains unclear. The objective of this study is to compare the clinical results of ACL reconstruction using the STDB and STSB techniques. Methods Between March 2010 to June 2013, 78 patients with ACL rupture underwent arthroscopic STDB reconstruction (42 cases) or STSB reconstruction (36 cases) using anterior tibialis tendon allografts in our department. IKDC, Lysholm and Tegner scores were used to evaluate the subjective function of the knee joint during the postoperative follow-up. In addition, the Lachman test and pivot shift test were used to objectively assess the stability of the knee. Results The average follow-up time is 24.2 ± 5.7 months in the STDB group, and 24.8 ± 6.6 months in the STSB group. Patients in both groups recovered to preoperative sports level with few complications. The postoperative Lysholm, IKDC, Tegner scores, and knee joint stability were significantly improved compared to preoperative status in both groups (P < 0.05). However, no statistically significant difference was observed between the two groups at the final follow-up (P > 0.05), except for the improvement of pivot shift test positive rate in the STDB group compared with STSB group (P < 0.05). Conclusion Both techniques can be used to restore the stability and function of the knee joint with satisfactory short-term efficacy, and STDB showed better rotational stability than STSB technique, indicating the STDB technique may also considered a reliable method for ACL reconstruction.

scholarly journals Arthroscopic reconstruction of anterior cruciate ligaments with allograft: Single-tunnel double-bundle versus single-tunnel single-bundle

2021 ◽  
Author(s):  
Weimin Zhu ◽  
Yizi Zheng ◽  
Wei Lu ◽  
Jianyi Xiong ◽  
Daping Wang ◽  
...  
Keyword(s):  
Knee Joint ◽  
Acl Reconstruction ◽  
Pivot Shift ◽  
Double Bundle ◽  
Pivot Shift Test ◽  
Single Bundle ◽  
Arthroscopic Reconstruction ◽  
Anterior Cruciate ◽  
The Stability

Abstract Background: Arthroscopic reconstruction of anterior cruciate ligament (ACL) commonly adopted single-tunnel single-bundle (STSB) or double-tunnel double-bundle (DTDB) methods. Though single-tunnel double-bundle (STDB) has been used in clinical practice, the efficacy remains unclear. The objective of this study is to compare the clinical results of ACL reconstruction using the STDB and STSB techniques.Methods: Between March 2010 to June 2013, 78 patients with ACL rupture underwent arthroscopic STDB reconstruction (42 cases) or STSB reconstruction (36 cases) using anterior tibialis tendon allografts in our department. IKDC, Lysholm and Tegner scores were used to evaluate the subjective function of the knee joint during the postoperative follow-up. In addition, the Lachman test and pivot shift test were used to objectively assess the stability of the knee.Results: The average follow-up time is 24.2±5.7 months in the STDB group, and 24.8±6.6 months in the STSB group. Patients in both groups recovered to preoperative sports level with few complications. The postoperative Lysholm, IKDC, Tegner scores, and knee joint stability were significantly improved compared to preoperative status in both groups (P<0.05). However, no statistically significant difference was observed between the two groups at the final follow-up (P>0.05), except for the improvement of pivot shift test positive rate in the STDB group compared with STSB group (P<0.05).Conclusion: Both techniques can be used to restore the stability and function of the knee joint with satisfactory short-term efficacy, and STDB showed better rotational stability than STSB technique, indicating the STDB technique may also considered a reliable method for ACL reconstruction.

scholarly journals A retrospective study to compare the clinical effects of individualized anatomic single- and double-bundle anterior cruciate ligament reconstruction surgery

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kang Chen ◽  
Weimin Zhu ◽  
Yizi Zheng ◽  
Fangjie Zhang ◽  
Kan Ouyang ◽  
...  
Keyword(s):  
Knee Joint ◽  
Acl Reconstruction ◽  
Cruciate Ligament ◽  
Double Bundle ◽  
Anatomic Reconstruction ◽  
Reconstruction Surgery ◽  
Anterior Cruciate ◽  
The Stability ◽  
Reconstruction Group

Abstract To evaluate the clinical efficacy of single- and double- bundle individualized anatomic anterior cruciate ligament (ACL) reconstruction, we retrospectively analyzed the data and charts of 920 patients with ACL rupture who received individualized anatomic ACL reconstruction surgery at our center. All of the patients underwent arthroscopic ACL reconstruction with autologous hamstring tendons. The patients were divided into two groups: the single-bundle individualized anatomic reconstruction group (N = 539), and the double-bundle individualized anatomic reconstruction group (N = 381). The IKDC, Lysholm and Tegner scores were used to subjectively evaluate the function of the knee joint during the postoperative follow-up. The Lachman test, pivot shift test and KT-3000 were used to objectively evaluate the stability of the knee. All 920 patients participated in clinical follow-up (average duration: 27.91 ± 3.61 months) achieved satisfied outcomes with few complications. The postoperative IKDC, Lysholm and Tegner scores, and the objective evaluation of knee joint stability were significantly improved compared to the preoperative status in both groups (P < 0.05). No statistically significant difference was observed between the two groups at the final follow-up (P > 0.05). Therefore, no difference in terms of the IKDC, Lysholm and Tegner score, or KT-3000 was observed between the individualized anatomic single- and double-bundle ACL reconstruction techniques. Both techniques can be used to restore the stability and functionality of the knee joint with satisfactory short-term efficacy.

scholarly journals Arthroscopic reconstruction of anterior cruciate ligaments with allograft: Single-tunnel double-bundle versus single-tunnel single-bundle

2020 ◽  
Author(s):  
Weimin Zhu ◽  
Yuanhui Zhou ◽  
Kang Chen ◽  
Yizi Zheng ◽  
Wei Lu ◽  
...  
Keyword(s):  
Knee Joint ◽  
Acl Reconstruction ◽  
Pivot Shift ◽  
Double Bundle ◽  
Pivot Shift Test ◽  
Single Bundle ◽  
Arthroscopic Reconstruction ◽  
Anterior Cruciate ◽  
The Stability

Abstract Purpose: Arthroscopic reconstruction of anterior cruciate ligament (ACL) commonly adopted single-tunnel single-bundle (STSB) or double-tunnel double-bundle (DTDB) methods. Though single-tunnel double-bundle (STDB) has been used in clinical practice, the efficacy remains unclear. The objective of this study is to compare the clinical results of ACL reconstruction using the STDB and STSB techniques.Methods: Between March 2010 to June 2013, 78 patients with ACL rupture underwent arthroscopic STDB reconstruction (42 cases) or STSB reconstruction (36 cases) using anterior tibialis tendon allografts in our department. IKDC, Lysholm and Tegner scores were used to evaluate the subjective function of the knee joint during the postoperative follow-up. In addition, the Lachman test and pivot shift test were used to objectively assess the stability of the knee.Results: The average follow-up time is 24.2±5.7 months in the STDB group, and 24.8±6.6 months in the STSB group. Patients in both groups recovered to preoperative sports level with few complications. The postoperative Lysholm, IKDC, Tegner scores, and knee joint stability were significantly improved compared to preoperative status in both groups (P<0.05). However, no statistically significant difference was observed between the two groups at the final follow-up (P>0.05), except for the improvement of pivot shift test positive rate in the STDB group compared with STSB group (P<0.05).Conclusion: Both techniques can be used to restore the stability and function of the knee joint with satisfactory short-term efficacy, and STDB showed better rotational stability than STSB technique, indicating the STDB technique may also considered a reliable method for ACL reconstruction.

scholarly journals Bone augmentation with autologous tooth shell in the esthetic zone for dental implant restoration: a pilot study

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Shuyi Li ◽  
Ming Gao ◽  
Miao Zhou ◽  
Yibo Zhu
Keyword(s):  
Dental Implants ◽  
Dental Implant ◽  
Three Dimensional ◽  
Radiographic Examination ◽  
Bone Augmentation ◽  
One Year ◽  
The Stability ◽  
The One ◽  
Implant Restoration

Abstract Objectives To investigate the outcome and short-term follow-up of autogenous tooth shell (TS) grafting for bone augmentation in the esthetic zone, as well as stability and esthetics of implant-supported restoration. Materials and methods A total of 8 patients with 11 implants in 11 sites were enrolled in this study. All the horizontal and/or vertical bone defects in the esthetic zone were augmented by tooth shells, which were fixed laterally to the residual bone with osteosynthesis screws. The gap between the shell and residual bone was filled with Bio-Oss® granules. Four months after bone augmentation, dimensionally sufficient dental implants were inserted and implants-supported prostheses were made 3 months later. The esthetic outcome was evaluated by pink esthetic score (PES) and white esthetic score (WES) one year after prosthetic restoration. Horizontal ridge width (HRW) was assessed before and immediately after bone augmentation, as well as 4 and 19 months post-augmentation by radiography. The stability and absorption of TS grafts were evaluated at the 4th and 19th months post-augmentation. Results Though wound dehiscences occurred in 3 cases, secondary healings were obtained after TS modification and irrigation. The other 5 cases went through uneventful healing during the whole observation period. Radiographic examination showed that HRW was 8.01 ± 0.93 mm (median: 7.80, 95% CI 7.38, 8.64) 4 months after TS augmentation, which was statistically different compared to HRW (2.72 ± 1.73 mm) at the baseline. Mean HRW gain was 5.29 ± 2.03 mm (median: 4.60, 95% CI 3.92, 6.66). Three-dimensional bone volume in all the augmented sites was sufficient for dental implants insertion and prosthetic restoration. Follow-up of one year showed stable marginal bone around dental implants. The implant survival rate was 100%. HRW losses were 0.65 ± 0.43 mm (the 4th month) and 1.05 ± 0.54 mm (the 19th month) compared to HRW immediately after augmentation. The PES and WES of final prosthetic restorations were 8.09 ± 0.70 and 8.91 ± 0.54, respectively. Conclusions Autogenous tooth shell grafting is a reliable approach for bone augmentation in the esthetic zone for dental implant treatment, allowing for favorable stability and esthetic outcome of implant-supported prosthesis within the one-year follow-up period.

Catheter-directed foam sclerotherapy treatment of saphenous vein incompetence

VASA ◽  
2012 ◽  
Vol 41 (2) ◽  
pp. 120-124 ◽  
Author(s):  
Asciutto ◽  
Lindblad
Keyword(s):  
Saphenous Vein ◽  
Short Term ◽  
Foam Sclerotherapy ◽  
Results Of Treatment ◽  
Ulcer Healing Rate ◽  
Complete Obliteration ◽  
Ceap Classification ◽  
One Year ◽  
The One

Background: The aim of this study is to report the short-term results of catheter-directed foam sclerotherapy (CDFS) in the treatment of axial saphenous vein incompetence. Patients and methods: Data of all patients undergoing CDFS for symptomatic primary incompetence of the great or small saphenous vein were prospectively collected. Treatment results in terms of occlusion rate and patients’ grade of satisfaction were analysed. All successfully treated patients underwent clinical and duplex follow-up examinations one year postoperatively. Results: Between September 2006 and September 2010, 357 limbs (337 patients) were treated with CDFS at our institution. Based on the CEAP classification, 64 were allocated to clinical class C3 , 128 to class C4, 102 to class C5 and 63 to class C6. Of the 188 patients who completed the one year follow up examination, 67 % had a complete and 14 % a near complete obliteration of the treated vessel. An ulcer-healing rate of 54 % was detected. 92 % of the patients were satisfied with the results of treatment. We registered six cases of thrombophlebitis and two cases of venous thromboembolism, all requiring treatment. Conclusions: The short-term results of CDFS in patients with axial vein incompetence are acceptable in terms of occlusion and complications rates.

Use of a Lyophilized Reference Plasma to Compare Coagulation Test Procedures

1975 ◽  
Vol 34 (02) ◽  
pp. 426-444 ◽  
Author(s):  
J Kahan ◽  
I Nohén
Keyword(s):  
Oral Anticoagulant Therapy ◽  
Repeated Measurements ◽  
Test Procedures ◽  
Coagulation Activity ◽  
Close Relationship ◽  
Measured Activity ◽  
Test Materials ◽  
The Difference ◽  
The Stability ◽  
The One

SummaryIn 4 collaborative trials, involving a varying number of hospital laboratories in the Stockholm area, the coagulation activity of different test materials was estimated with the one-stage prothrombin tests routinely used in the laboratories, viz. Normotest, Simplastin-A and Thrombotest. The test materials included different batches of a lyophilized reference plasma, deep-frozen specimens of diluted and undiluted normal plasmas, and fresh and deep-frozen specimens from patients on long-term oral anticoagulant therapy.Although a close relationship was found between different methods, Simplastin-A gave consistently lower values than Normotest, the difference being proportional to the estimated activity. The discrepancy was of about the same magnitude on all the test materials, and was probably due to a divergence between the manufacturers’ procedures used to set “normal percentage activity”, as well as to a varying ratio of measured activity to plasma concentration. The extent of discrepancy may vary with the batch-to-batch variation of thromboplastin reagents.The close agreement between results obtained on different test materials suggests that the investigated reference plasma could be used to calibrate the examined thromboplastin reagents, and to compare the degree of hypocoagulability estimated by the examined PIVKA-insensitive thromboplastin reagents.The assigned coagulation activity of different batches of the reference plasma agreed closely with experimentally obtained values. The stability of supplied batches was satisfactory as judged from the reproducibility of repeated measurements. The variability of test procedures was approximately the same on different test materials.

Comparing the effect of preparation of the implant sites with piezosurgery and conventional drilling on the stability of implants at 5-months follow-up

2018 ◽  
Vol 28 (1) ◽  
pp. 1-8
Author(s):  
Sara Soheilifar ◽  
Mohsen Bidgoli ◽  
Ehsan Houshyar ◽  
Maryam Farhadian ◽  
Ali Ghamari
Keyword(s):  
The Stability ◽  
Conventional Drilling
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