ANTEROMEDIAL ROTATORY INSTABILITY: A BIOMECHANICAL STUDY OF MEDIAL SOFT-TISSUE RESTRAINTS IN-VITRO

Abstract Background All current total hip arthroplasty (THA) systems are modular in design. Only during the operation femoral head and stem get connected by a Morse taper junction. The junction is realized by hammer blows from the surgeon. Decisive for the junction strength is the maximum force acting once in the direction of the neck axis, which is mainly influenced by the applied impulse and surrounding soft tissues. This leads to large differences in assembly forces between the surgeries. This study aimed to quantify the assembly forces of different surgeons under influence of surrounding soft tissue. Methods First, a measuring system, consisting of a prosthesis and a hammer, was developed. Both components are equipped with a piezoelectric force sensor. Initially, in situ experiments on human cadavers were carried out using this system in order to determine the actual assembly forces and to characterize the influence of human soft tissues. Afterwards, an in vitro model in the form of an artificial femur (Sawbones Europe AB, Malmo, Sweden) with implanted measuring stem embedded in gelatine was developed. The gelatine mixture was chosen in such a way that assembly forces applied to the model corresponded to those in situ. A study involving 31 surgeons was carried out on the aforementioned in vitro model, in which the assembly forces were determined. Results A model was developed, with the influence of human soft tissues being taken into account. The assembly forces measured on the in vitro model were, on average, 2037.2 N ± 724.9 N, ranging from 822.5 N to 3835.2 N. The comparison among the surgeons showed no significant differences in sex (P = 0.09), work experience (P = 0.71) and number of THAs performed per year (P = 0.69). Conclusions All measured assembly forces were below 4 kN, which is recommended in the literature. This could lead to increased corrosion following fretting in the head-neck interface. In addition, there was a very wide range of assembly forces among the surgeons, although other influencing factors such as different implant sizes or materials were not taken into account. To ensure optimal assembly force, the impaction should be standardized, e.g., by using an appropriate surgical instrument.

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The fixation strength of a novel ACL soft-tissue graft fixation device compared with conventional interference screws: a biomechanical study in vitro

Knee Surgery Sports Traumatology Arthroscopy ◽

10.1007/s00167-010-1255-5 ◽

2010 ◽

Vol 19 (4) ◽

pp. 559-567 ◽

Cited By ~ 23

Author(s):

Camilla Halewood ◽

Michael T. Hirschmann ◽

Simon Newman ◽

Jaffar Hleihil ◽

Gershon Chaimski ◽

...

Keyword(s):

Soft Tissue ◽

Biomechanical Study ◽

Graft Fixation ◽

Fixation Strength ◽

Fixation Device ◽

Interference Screws ◽

Tissue Graft ◽

Soft Tissue Graft

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Effect of ulnar angulation and soft tissue sectioning on radial head stability in anterior Monteggia injuries: an in vitro biomechanical study

Journal of Shoulder and Elbow Surgery ◽

10.1016/j.jse.2019.10.025 ◽

2020 ◽

Vol 29 (6) ◽

pp. 1249-1258

Author(s):

Armin Badre ◽

David T. Axford ◽

Clare E. Padmore ◽

Carolyn Berkmortel ◽

Kenneth J. Faber ◽

...

Keyword(s):

Soft Tissue ◽

Radial Head ◽

Biomechanical Study ◽

Head Stability

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The medial ligaments and the ACL restrain anteromedial laxity of the knee

Knee Surgery Sports Traumatology Arthroscopy ◽

10.1007/s00167-020-06084-4 ◽

2020 ◽

Vol 28 (12) ◽

pp. 3700-3708 ◽

Cited By ~ 2

Author(s):

S. Ball ◽

J. M. Stephen ◽

H. El-Daou ◽

A. Williams ◽

Andrew A. Amis

Keyword(s):

Graft Failure ◽

External Rotation ◽

Collateral Ligament ◽

Rotatory Instability ◽

Posterior Translation ◽

Anteromedial Rotatory Instability ◽

Posteromedial Capsule ◽

Intact Knee ◽

Anterior Posterior

Abstract Purpose The purpose of this study was to determine the contribution of each of the ACL and medial ligament structures in resisting anteromedial rotatory instability (AMRI) loads applied in vitro. Methods Twelve knees were tested using a robotic system. It imposed loads simulating clinical laxity tests at 0° to 90° flexion: ±90 N anterior–posterior force, ±8 Nm varus–valgus moment, and ±5 Nm internal–external rotation, and the tibial displacements were measured in the intact knee. The ACL and individual medial structures—retinaculum, superficial and deep medial collateral ligament (sMCL and dMCL), and posteromedial capsule with oblique ligament (POL + PMC)—were sectioned sequentially. The tibial displacements were reapplied after each cut and the reduced loads required allowed the contribution of each structure to be calculated. Results For anterior translation, the ACL was the primary restraint, resisting 63–77% of the drawer force across 0° to 90°, the sMCL contributing 4–7%. For posterior translation, the POL + PMC contributed 10% of the restraint in extension; other structures were not significant. For valgus load, the sMCL was the primary restraint (40–54%) across 0° to 90°, the dMCL 12%, and POL + PMC 16% in extension. For external rotation, the dMCL resisted 23–13% across 0° to 90°, the sMCL 13–22%, and the ACL 6–9%. Conclusion The dMCL is the largest medial restraint to tibial external rotation in extension. Therefore, following a combined ACL + MCL injury, AMRI may persist if there is inadequate healing of both the sMCL and dMCL, and MCL deficiency increases the risk of ACL graft failure.

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The Effect of Volarly Angulated Distal Radius Fractures on Forearm Rotation: In Vitro Biomechanical Study

Journal of Wrist Surgery ◽

10.1055/s-0035-1544221 ◽

2015 ◽

Vol 04 (S 01) ◽

Author(s):

Masao Nishiwaki ◽

Mark Welsh ◽

Louis Ferreira ◽

James Johnson ◽

Graham King ◽

...

Keyword(s):

Distal Radius ◽

Biomechanical Study ◽

Distal Radius Fractures ◽

Radius Fractures ◽

Forearm Rotation

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Evaluation of 99mTc-Label led Vitamin K4 as an Agent for Testicular Imaging

Nuklearmedizin ◽

10.1055/s-0038-1629552 ◽

1991 ◽

Vol 30 (01) ◽

pp. 35-39 ◽

Cited By ~ 1

Author(s):

H. S. Durak ◽

M. Kitapgi ◽

B. E. Caner ◽

R. Senekowitsch ◽

M. T. Ercan

Keyword(s):

Soft Tissue ◽

Room Temperature ◽

Normal Subjects ◽

Left Testis ◽

Wide Range ◽

Activity Ratios ◽

The Right ◽

Radioactivity Levels

Vitamin K4 was labelled with 99mTc with an efficiency higher than 97%. The compound was stable up to 24 h at room temperature, and its biodistribution in NMRI mice indicated its in vivo stability. Blood radioactivity levels were high over a wide range. 10% of the injected activity remained in blood after 24 h. Excretion was mostly via kidneys. Only the liver and kidneys concentrated appreciable amounts of radioactivity. Testis/soft tissue ratios were 1.4 and 1.57 at 6 and 24 h, respectively. Testis/blood ratios were lower than 1. In vitro studies with mouse blood indicated that 33.9 ±9.6% of the radioactivity was associated with RBCs; it was washed out almost completely with saline. Protein binding was 28.7 ±6.3% as determined by TCA precipitation. Blood clearance of 99mTc-l<4 in normal subjects showed a slow decrease of radioactivity, reaching a plateau after 16 h at 20% of the injected activity. In scintigraphic images in men the testes could be well visualized. The right/left testis ratio was 1.08 ±0.13. Testis/soft tissue and testis/blood activity ratios were highest at 3 h. These ratios were higher than those obtained with pertechnetate at 20 min post injection.99mTc-l<4 appears to be a promising radiopharmaceutical for the scintigraphic visualization of testes.

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Role of the anconeus in the stability of a lateral ligament and common extensor origin–deficient elbow: an in vitro biomechanical study

Journal of Shoulder and Elbow Surgery ◽

10.1016/j.jse.2018.11.040 ◽

2019 ◽

Vol 28 (5) ◽

pp. 974-981 ◽

Cited By ~ 1

Author(s):

Armin Badre ◽

David T. Axford ◽

Sara Banayan ◽

James A. Johnson ◽

Graham J.W. King

Keyword(s):

Biomechanical Study ◽

Lateral Ligament ◽

The Stability

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Whether sutures reduce the graft laceration caused by interference screw in anterior cruciate ligament reconstruction? A biomechanical study in vitro

BMC Musculoskeletal Disorders ◽

10.1186/s12891-021-04457-5 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Yuanjun Teng ◽

Xiaohui Zhang ◽

Lijun Da ◽

Jie Hu ◽

Hong Wang ◽

...

Keyword(s):

Acl Reconstruction ◽

Cruciate Ligament ◽

Interference Screw ◽

Biomechanical Study ◽

Interference Screws ◽

Suture Group ◽

Anterior Cruciate ◽

Biomechanical Tests ◽

Single Insertion

Abstract Background Interference screw is commonly used for graft fixation in anterior cruciate ligament (ACL) reconstruction. However, previous studies had reported that the insertion of interference screws significantly caused graft laceration. The purposes of this study were to (1) quantitatively evaluate the graft laceration from one single insertion of PEEK interference screws; and (2) determine whether different types of sutures reduced the graft laceration after one single insertion of interference screws in ACL reconstruction. Methods The in-vitro ACL reconstruction model was created using porcine tibias and bovine extensor digitorum tendons of bovine hind limbs. The ends of grafts were sutured using three different sutures, including the bioabsorbable, Ethibond and ultra-high molecular weight polyethylene (UHMWPE) sutures. Poly-ether-ether-ketone (PEEK) interference screws were used for tibial fixation. This study was divided into five groups (n = 10 in each group): the non-fixed group, the non-sutured group, the absorbable suture group, the Ethibond suture group and the UHMWPE suture group. Biomechanical tests were performed using the mode of pull-to-failure loading tests at 10 mm/min. Tensile stiffness (newtons per millimeter), energy absorbed to failure (in joules) and ultimate load (newtons) were recorded for analysis. Results All prepared tendons and bone specimens showed similar characteristics (length, weight, and pre-tension of the tendons, tibial bone mineral density) among all groups (P > 0.05). The biomechanical tests demonstrated that PEEK interference screws significantly caused the graft laceration (P < 0.05). However, all sutures (the bioabsorbable, Ethibond and UHMWPE sutures) did not reduce the graft laceration in ACL reconstruction (P > 0.05). Conclusions Our biomechanical study suggested that the ultimate failure load of grafts was reduced of approximately 25 % after one single insertion of a PEEK interference screw in ACL reconstruction. Suturing the ends of the grafts using different sutures (absorbable, Ethibond and UHMWPE sutures) did not decrease the graft laceration caused by interference screws.

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The Effectiveness of a Hinged Elbow Orthosis in Medial Collateral Ligament Injuries: An In Vitro Biomechanical Study

The American Journal of Sports Medicine ◽

10.1177/0363546519870517 ◽

2019 ◽

Vol 47 (12) ◽

pp. 2827-2835

Author(s):

Ranita H.K. Manocha ◽

James A. Johnson ◽

Graham J.W. King

Keyword(s):

Medial Collateral Ligament ◽

Muscle Activation ◽

Mechanical Stability ◽

Biomechanical Study ◽

Return To Play ◽

Collateral Ligament ◽

Valgus Stress ◽

Active Motion ◽

Early Return

Background: Medial collateral ligament (MCL) injuries are common after elbow trauma and in overhead throwing athletes. A hinged elbow orthosis (HEO) is often used to protect the elbow from valgus stress early after injury and during early return to play. However, there is minimal evidence regarding the efficacy of these orthoses in controlling instability and their influence on long-term clinical outcomes. Purpose: (1) To quantify the effect of an HEO on elbow stability after simulated MCL injury. (2) To determine whether arm position, forearm rotation, and muscle activation influence the effectiveness of an HEO. Study Design: Controlled laboratory study. Methods: Seven cadaveric upper extremity specimens were tested in a custom simulator that enabled elbow motion via computer-controlled actuators and motors attached to relevant tendons. Specimens were examined in 2 arm positions (dependent, valgus) and 2 forearm positions (pronation, supination) during passive and simulated active elbow flexion while unbraced and then while braced with an HEO. Testing was performed in intact elbows and repeated after simulated MCL injury. An electromagnetic tracking device measured valgus angulation as an indicator of elbow stability. Results: When the arm was dependent, the HEO increased valgus angle with the forearm in pronation (+1.0°± 0.2°, P = .003) and supination (+1.5°± 0.0°, P = .006) during active motion. It had no significant effect on elbow stability during passive motion. In the valgus position, the HEO had no effect on elbow stability during passive or active motion in pronation and supination. With the arm in the valgus position with the HEO, muscle activation reduced instability during pronation (–10.3°± 2.5°, P = .006) but not supination ( P = .61). Conclusion: In this in vitro study, this HEO did not enhance mechanical stability when the arm was in the valgus and dependent positions after MCL injury. Clinical Relevance: After MCL injury, an HEO likely does not provide mechanical elbow stability during rehabilitative exercises or when the elbow is subjected to valgus stress such as occurs during throwing.

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