Treatment of Acute Ankle Syndesmodic Injury by Elastic Fixation

The paper presents solutions to the direct and inverse problems on longitudinal vibrations of a rod with a variable cross-sectional area. The law of variation of the cross-sectional area is modeled as an exponential function of a polynomial of degree n . The method for reconstructing this function is based on representing the fundamental system of solutions of the direct problem in the form of a Maclaurin series in the variables x and λ. Examples of solutions for various section functions and various boundary conditions are given. It is shown that to recover n unknown coefficients of a polynomial, n eigenvalues are required, and the solution is dual. An unambiguous solution was obtained only for the case of elastic fixation at one of the rod’s ends. The numerical estimation of the method error was made using input data noise. It is shown that the error in finding the variable crosssectional area is less than 1% with the error in the eigenvalues of longitudinal vibrations not exceeding 0.0001.

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Peri-acetabular bone remodelling after uncemented total hip arthroplasty with monoblock press-fit cups: an observational study

BMC Musculoskeletal Disorders ◽

10.1186/s12891-020-03675-7 ◽

2020 ◽

Vol 21 (1) ◽

Author(s):

Conrad Anderl ◽

Georg Mattiassich ◽

Reinhold Ortmaier ◽

Martin Steinmair ◽

Josef Hochreiter

Keyword(s):

Observational Study ◽

Bone Remodelling ◽

Central Zone ◽

Rigid Fixation ◽

Mineral Density ◽

Acetabular Bone ◽

Total Hip ◽

Press Fit ◽

Uncemented Total Hip Arthroplasty ◽

Elastic Fixation

Abstract Background Bone stock preservation in total hip replacement is essential to allow for later revisions in an increasingly younger and fitter index patient population. While contemporary modular press-fit acetabular cups lead to rigid fixation with equatorial stress and central osteolysis, more elastic fixation may cause different peri-acetabular bone remodelling. The purpose of this study was to investigate changes in peri-acetabular bone mineral density (BMD) in uncemented elastic fixation with monoblock press-fit cups. Methods This prospective observational study included 45 patients with monoblock cups. We evaluated peri-acetabular BMD using dual-energy X-ray absorptiometry and reported functional outcomes and complications. Results At a mean follow-up of 24.2 ± 2.2 months, we found that BMD stabilised in DeLee and Charnley zones I and III and recovered to baseline value in zone II. The mean Harris Hip Scores improved significantly from 56.9 ± 20.0 to 97.2 ± 4.0 (p < 0001). Other than one peri-operative dislocation, we saw no post-operative complications. Conclusions We found favourable adaptive bone changes with BMD stabilisation in the equatorial zones and recovery to pre-operative values in the central zone. Additionally, excellent clinical outcomes and few prosthesis-related complications strengthened the favourable results of monoblock acetabular cups. Trial registration Registration number DRKS00017076.

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Stability of the Anterior Maxillary Segment and Teeth after Segmental Le Fort I Osteotomy and Postoperative Skeletal Elastic Fixation With or Without Occlusal Splint

Journal of Oral and Maxillofacial Research ◽

10.5037/jomr.2014.5304 ◽

2014 ◽

Vol 5 (3) ◽

Cited By ~ 4

Author(s):

Tue Lindberg Blæhr ◽

Thomas Jensen ◽

Karen Margrethe Due ◽

Bjarne Neumann-Jensen

Keyword(s):

Occlusal Splint ◽

Le Fort I Osteotomy ◽

Le Fort ◽

Elastic Fixation ◽

Le Fort I

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Peri-acetabular bone remodelling after uncemented total hip arthroplasty with monoblock press-fit cups: an observational study

10.21203/rs.3.rs-19063/v3 ◽

2020 ◽

Author(s):

Conrad Anderl ◽

Georg Mattiassich ◽

Reinhold Ortmaier ◽

Martin Steinmair ◽

Josef Hochreiter

Keyword(s):

Observational Study ◽

Bone Remodelling ◽

Central Zone ◽

Rigid Fixation ◽

Mineral Density ◽

Acetabular Bone ◽

Total Hip ◽

Press Fit ◽

Uncemented Total Hip Arthroplasty ◽

Elastic Fixation

Abstract Background: Bone stock preservation in total hip replacement is essential to allow for later revisions in an increasingly younger and fitter index patient population. While contemporary modular press-fit acetabular cups lead to rigid fixation with equatorial stress and central osteolysis, more elastic fixation may cause different peri-acetabular bone remodelling. The purpose of this study was to investigate changes in peri-acetabular bone mineral density (BMD) in uncemented elastic fixation with monoblock press-fit cups.Methods: This prospective observational study included 45 patients with monoblock cups. We evaluated peri-acetabular BMD using dual-energy X-ray absorptiometry and reported functional outcomes and complications.Results: At a mean follow-up of 24.2 ± 2.2 months, we found that BMD stabilised in DeLee and Charnley zones I and III and recovered to baseline value in zone II. The mean Harris Hip Scores improved significantly from 56.9 ± 20.0 to 97.2 ± 4.0 (p < 0001). Other than one peri-operative dislocation, we saw no post-operative complications.Conclusions: We found favourable adaptive bone changes with BMD stabilisation in the equatorial zones and recovery to pre-operative values in the central zone. Additionally, excellent clinical outcomes and few prosthesis-related complications strengthened the favourable results of monoblock acetabular cups.Trial registration: Registration number DRKS00017076.

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Peri-acetabular bone remodelling after uncemented total hip arthroplasty with monoblock press-fit cups: an observational study

10.21203/rs.3.rs-19063/v1 ◽

2020 ◽

Author(s):

Conrad Anderl ◽

Georg Mattiassich New ◽

Reinhold Ortmaier New ◽

Martin Steinmair New ◽

Josef Hochreiter New

Keyword(s):

Observational Study ◽

Bone Remodelling ◽

Central Zone ◽

Rigid Fixation ◽

Mineral Density ◽

Acetabular Bone ◽

Total Hip ◽

Press Fit ◽

Uncemented Total Hip Arthroplasty ◽

Elastic Fixation

Abstract Background: Bone stock preservation in total hip replacement is essential to allow for later revisions in an increasingly younger and fitter index patient population. While contemporary modular press-fit acetabular cups lead to rigid fixation with equatorial stress and central osteolysis, more elastic fixation may cause different peri-acetabular bone remodelling. The purpose of this study was to investigate changes in peri-acetabular bone mineral density (BMD) in uncemented elastic fixation with monoblock press-fit cups.Methods: This prospective observational study included 45 patients with monoblock cups. We evaluated peri-acetabular BMD using dual-energy X-ray absorptiometry and reported functional outcomes and complications.Results: At a mean follow-up of 24.2 ± 2.2 months, we found that BMD stabilised in DeLee and Charnley zones I and III and recovered to baseline value in zone II. The mean Harris Hip Scores improved significantly from 56.9 ± 20.0 to 97.2 ± 4.0 (p < 0001). Other than one peri-operative dislocation, we saw no post-operative complications.Conclusions: We confirmed favourable adaptive bone changes with BMD stabilisation in the equatorial zones and recovery to pre-operative values in the central zone. Additionally, excellent clinical outcomes and few prosthesis-related complications confirmed the favourable results of monoblock acetabular cups.

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ON SMOOTHNESS OF SOLUTION OF ONE NONLOCAL PROBLEM FOR HYPERBOLIC EQUATION

Vestnik of Samara University Natural Science Series ◽

10.18287/2541-7525-2020-26-2-15-22 ◽

2021 ◽

Vol 26 (2) ◽

pp. 15-22

Author(s):

V. A. Kirichek

Keyword(s):

Hyperbolic Equation ◽

Nonlocal Problem ◽

Generalized Solution ◽

Integral Boundary ◽

Apriori Estimates ◽

The Space L2 ◽

Elastic Fixation ◽

The Right ◽

Derivatives Of ◽

Smoothness Of Solution

In this paper we consider a nonlocal problem with integral boundary condition for hyperbolic equation. The conditions of the problem contain derivatives of the first order with respect to both x and t,, which can be interpreted as an elastic fixation of the right end rod in the presence of a certain damper, and since the conditions also contain integral of the desired solution, this condition is nonlocal. It is known that problems with nonlocal integral conditions are non-self-adjoint and, therefore, the study of solvability encounters difficulties that are not characteristic of self-adjoint problems. Additional difficulties arise also due to the fact that one of the conditions is dynamic. The attention of the article is focused on studying thesmoothness of the solution of the nonlocal problem. The concept of a generalized solution is introduced, and the existence of second-order derivatives and their belonging to the space L2 are proved. The proof is basedon apriori estimates obtained in this work.

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Elastic fixation of mallet finger fractures using two K-wires

Medicine ◽

10.1097/md.0000000000015481 ◽

2019 ◽

Vol 98 (20) ◽

pp. e15481

Author(s):

Qiang Chen ◽

Yan Suo ◽

Danhong Pan ◽

QingPing Xie

Keyword(s):

Mallet Finger ◽

K Wires ◽

Elastic Fixation

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Peri-acetabular bone remodelling after uncemented total hip arthroplasty with monoblock press-fit cups: an observational study

10.21203/rs.3.rs-19063/v2 ◽

2020 ◽

Author(s):

Conrad Anderl ◽

Georg Mattiassich ◽

Reinhold Ortmaier ◽

Martin Steinmair ◽

Josef Hochreiter

Keyword(s):

Observational Study ◽

Bone Remodelling ◽

Central Zone ◽

Rigid Fixation ◽

Mineral Density ◽

Acetabular Bone ◽

Total Hip ◽

Press Fit ◽

Uncemented Total Hip Arthroplasty ◽

Elastic Fixation

Abstract Background: Bone stock preservation in total hip replacement is essential to allow for later revisions in an increasingly younger and fitter index patient population. While contemporary modular press-fit acetabular cups lead to rigid fixation with equatorial stress and central osteolysis, more elastic fixation may cause different peri-acetabular bone remodelling. The purpose of this study was to investigate changes in peri-acetabular bone mineral density (BMD) in uncemented elastic fixation with monoblock press-fit cups.Methods: This prospective observational study included 45 patients with monoblock cups. We evaluated peri-acetabular BMD using dual-energy X-ray absorptiometry and reported functional outcomes and complications.Results: At a mean follow-up of 24.2 ± 2.2 months, we found that BMD stabilised in DeLee and Charnley zones I and III and recovered to baseline value in zone II. The mean Harris Hip Scores improved significantly from 56.9 ± 20.0 to 97.2 ± 4.0 (p < 0001). Other than one peri-operative dislocation, we saw no post-operative complications.Conclusions: We found favourable adaptive bone changes with BMD stabilisation in the equatorial zones and recovery to pre-operative values in the central zone. Additionally, excellent clinical outcomes and few prosthesis-related complications strengthened the favourable results of monoblock acetabular cups.Trial registration: Registration number DRKS00017076.

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Clinical outcomes of Tightrope system in the treatment of purely ligamentous Lisfranc injuries

BMC Surgery ◽

10.1186/s12893-021-01394-x ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Fan Yongfei ◽

Liu Chaoyu ◽

Xu Wenqiang ◽

Ma Xiulin ◽

Xu Jian ◽

...

Keyword(s):

Rigid Fixation ◽

Operative Techniques ◽

Biomechanical Stability ◽

X Ray ◽

Vas Score ◽

Second Metatarsal ◽

Significant Difference ◽

Elastic Fixation ◽

Lisfranc Injuries

Abstract Background Purely ligamentous Lisfranc injuries are mainly caused by low energy damage and often require surgical treatment. There are several operative techniques for rigid fixation to solve this problem clinically. This study evaluated the effect of using the Tightrope system to reconstruct the Lisfranc ligament for elastic fixation. Methods We retrospectively analyzed 11 cases with purely ligamentous Lisfranc injuries treated with the Tightrope system from 2016 to 2019, including 8 male and 3 female. X-ray was performed regularly after operation to measure the distance between the first and second metatarsal joint and the visual analogue scale (VAS) score was used to evaluate pain relief. American orthopedic foot & ankle society (AOFAS) and Maryland foot score were recorded at the last follow-up. Results The average follow-up time was 20.5 months (range, 17–24). There was statistically significant difference in the distance between the first and second metatarsal joint and VAS score at 3 months, 6 months, and the last follow-up when compared with preoperative values (P < 0.05).Mean of postoperative AOFAS mid-foot scale and Maryland foot score were 92.4 ± 4.3, 94.1 ± 3.5, respectively. The Tightrope system was not removed and the foot obtained better biomechanical stability. No complications occurred during the operation. Conclusion Tightrope system in the treatment of purely ligamentous Lisfranc injuries can stabilize the tarsometatarsal joint and achieve satisfactory effect.

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Mathematical Modelling of Destabilization Stress Factors of Stable-Elastic Fixation of Distal Trans- and Suprasyndesmotic Fibular Fractures

Journal of Healthcare Engineering ◽

10.1155/2021/6607364 ◽

2021 ◽

Vol 2021 ◽

pp. 1-8

Author(s):

Andriy Chuzhak ◽

Vadym Sulyma ◽

Lіubomyr Ropyak ◽

Andrii Velychkovych ◽

Vasyl Vytvytskyi

Keyword(s):

Mathematical Modelling ◽

Intramedullary Nail ◽

Stress Factors ◽

Ankle Injuries ◽

Theoretical Research ◽

Bone Injury ◽

Thread Tension ◽

Elastic Thread ◽

Elastic Fixation ◽

Minimally Invasive Fixation

Introduction. Specification of possible stress factors destabilizing the fibula stable osteosynthesis by the intramedullary nail with distal blocking and elastic fixation of distal syndesmosis by the thread with endobuttons by mathematical modelling of distal unstable ankle injuries. Material and Methods. We studied the thread tension during the combined stable-elastic fixation of unstable injuries of the ankle joint in cross-syndesmosis fractures of the fibula (B, C Danis–Weber classification), which includes a one-time stable minimally invasive fixation with the intramedullary nail and elastic fixation by the thread with endobuttons. We used a titanium alloy for the intramedullary nail and polyester for the thread. The deformed state was studied using the methods of mechanics. Results. A model of a fractured fibula blocked with the intramedullary nail and fixed with the elastic thread was developed. A formulation to specify the rational tension forces of the elastic thread depending on the parameters of the fibula and intramedullary blocking nail and on the location of the bone injury was obtained. The effect of foot rotation on the thread tension was investigated. The results of theoretical research should be implemented in medical practice. Conclusions. A mathematical model of the damaged fibula blocked by the intramedullary nail and fixed with the elastic thread was developed. Dependences for calculation of tension of the fixing thread were obtained. A slight increase in thread tension during foot rotation was found.

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