Rotational Stability of Proximally Unlocked Retrograde Femoral Nail In Damage Control Surgery – Biomechanical Study

BACKGROUND: This biomechanical study was performed to look into the rotational stability of retrograde femoral intramedullary nail when it is used without proximal locking as a damage control device for management of femoral shaft fractures in emergency situations. This study compares this technique with the accepted methods for femoral shaft fixations in damage control surgeries. An alternative technique of using lateral compression screw to provide additional rotational stability is described.METHODS: Experiments were divided into four different sets. Distally locked retrograde nail was passed across the fracture without any proximal fixation in set 1, a compression screw passed from lateral cortex in set 2, a proximal locking screw fixation in set 3. In set 4, Saw bone was fixed with external fixator.The lateral compression screw group was further sub divided into three subgroups based on the amount of torque applied manually.The torsion test was applied to create an rotational displacement of 10 degrees and the maximum load required to create the rotational displacement was noted.RESULTS: Application of a compression screw improved the rotational stability significantly in comparison to no proximal locking. In the subgroup III of lateral compression screw application, the rotational stability was found to be equivalent to stability achieved with Nail with proximal locking and was found to be greater in comparison to external fixator application.CONCLUSION: This study shows that the addition of a lateral compression screw significantly improves rotational stability and has the potential to be used in emergency lifesaving procedures.

DIAGNOSTIC TACTICS FOR TRANSCONDYLAR AND SUPRACONDYLAR FRACTURES OF THE HUMERUS IN CHILDREN

Transcondylar and supracondylar fractures of the humerus in children are one of the most relevant and still not completely solved problems of modern pediatric traumatology. In the problem of condylar and supraorbital fractures of the humerus, the issues of diagnosis, choice of indications for surgical revision of the vascular-nervous bundle of the elbow area in this pathology are insufficiently covered. To solve the problems of the study, we analyzed the treatment of 313 victims with transcondylar and supracondylar fractures of the humerus, which were treated at the City Children's Clinical Hospital in Lviv in the period from 2013 to 2018. The structure of the distribution of arrays on the basis of rotational displacement in condylar fractures of the humerus is dominated by displacement up to 30°, which in the first group was found in 61.8% of cases, and in the second group - 69.2% of cases. The share of severe rotational displacements in the structure of group arrays is almost the same in both observation groups: 29.1% in the first group and 29.5% in the second group. Analysis of the proportion of extremely severe rotational displacements up to 90° in the structure of group arrays revealed that such victims were 7 times more among the victims of the first group than among the victims of the second group, due to the use of the proposed unified protocol scheme for diagnosis and treatment humeral fractures in pediatric patients, which avoids or reduces the difference in the occurrence of secondary displacements.

Successful One and One-half Ventricular Circulation with Bioprosthetic Tricuspid Valve Replacement and Total Chordal Preservation in a Patient with Ebstein’s Anomaly: A Video Presentation

Ebstein’s anomaly is a rare congenital malformation of the right ventricle and tricuspid valve which is characterized by several features that can exhibit an infinite spectrum of malformation.The abnormalities include: i) adherence of the tricuspid leaflets to the underlying myocardium (failure of delamination); ii) anterior and apical rotational displacement of the functional tricuspid annulus (septal > posterior > anterior leaflet); iii) dilatation of the right atrioventricular junction (the true tricuspid annulus) with variable degrees of hypertrophy and thinning of the wall; iv) dilatation of the “atrialized” portion of the right ventricle; and v) redundancy, fenestration, and tethering of the anterior leaflet.

The state of the problem of fractures of the distal metepiphysis of the humerus in children and adolescents

Annotation. One of the most frequent injuries of the distal end of the humerus is the trans-condylar and supracondylar fractures of the humerus, which make up 47.5-80% of all intraarticular fractures of the elbow joint in children. Among the injuries of the distal humerus, the supracondylar and supracondylar fractures occur with the greatest frequency and is one of the most common domestic injuries in children aged 3 to 12 years. Our work is based on a retrospective analysis of the treatment of 255 patients treated in the Lviv City Children's Hospital for the period 2013-2017. 83.1% of patients were diagnosed with flexion fracture, 16.9% – flexion fracture. Transvertebral fractures of the shoulder were diagnosed in 85.5% of cases of the study array, supragingival – in 14.5%. The treatment of patients with the consequences of injuries of the elbow joint presents great difficulties and remains one of the most difficult problems in pediatric traumatology. Depending on the presence of rotational displacement and the severity of the fracture, the following types of treatment are most often used: conservative, osteosynthesis with spokes or Ilizarov apparatus. An ideal reposition and stable fixation of fragments during these injuries is necessary not only to ensure timely consolidation of the fracture, restoration of the anatomical integrity and shape of the distal humerus, but also to prevent the development of deformation in the elbow joint. Deformations of the elbow joint during supracondylar and supracondylar fractures of the shoulder, unlike deformation of another localization, cannot be adjusted and subsequently only increase and as a result can lead to impaired function of the elbow joint, and often to disability already in childhood. Thus, complicated anatomical localization of supracondylar and supracondylar fractures of the humerus in children, great technical difficulties in comparing and fixing fragments, there is a high probability of neurological and vascular disorders, both at the time of injury and during the provision of medical care, impaired function of the elbow joint determine the need for further study of this problem.

Numerical and analytical study on the mechanical properties of a connector with long-fiber and metal laminated bolts for prefabricated construction

To improve the mechanical performances of joints in prefabricated construction, a type of connection structure with long-fiber and metal laminated bolts (referred to as a fiber-metal connector) is proposed and investigated by simulation and theoretical methods. The results include the following: (1) The fiber layer in bolts can form a second stiffness during rotation. This mechanical characteristic improves the bearing capacities and energy dissipation ability of the connector relative to the conventional metal connector, which are expected to effectively limit the elastoplastic rotational displacement of a structure. (2) For the reason, the fiber layer can bear load in the plastic phase due to its high-strength characteristic in the length direction. (3) A bilinear model for the bearing curve of the fiber-metal connector is proposed, and equations for optimization of fiber layer thickness are obtained with a target on bearing capacity and energy dissipation ability which are approximately higher 30% and 13% than that of the conventional metal connector, respectively. This research is expected to provide a theoretical basis for the application of this fiber-metal connector in engineering and improve the safety of prefabricated structures.

Re-Recognition of Garden Index as a Criterion for Evaluating the Quality of Femoral Neck Fracture Reduction: An Imaging Study Based on Cadaver Specimens

ObjectiveTo investigate whether the Garden index can determine the rotational displacement of femoral neck fracture. MethodsTen healthy human femoral specimens were obtained. A 2.0 mm diameter Kirschner-wire was placed in the center of the femoral head. The osteotomy was perpendicular in the middle of the femoral neck. The distal osteotomy surface was indicated the angle of rotation (pronation and supination to 90°, every 10° was an interval). The X-ray of anterior-posterior and lateral view was taken at different angles according to the mark. The Garden index and other relevant data were analyzed with the PCAS system. Meanwhile, the change of the area of the femoral head fovea at different rotation angles was observed. ResultsThere was no significant difference in the Garden index in 0~30° at pronation and supination position (P>0.05). In range of 40°~90°, there was a statistical difference in the Garden index (P<0.05). With the increase of the pronation angle, the area of the femoral head fovea is gradually reduced; as the angle of the supination increases, the area of the femoral head fovea is gradually increased. ConclusionThe Garden Index cannot accurately determine the rotational displacement of the femoral neck fracture during the pronation or supination range of 0~30°. Changes in the area of the femoral head fovea can help determine the rotational displacement of the femoral neck fracture.Level of EvidenceLevel V.

Motion and its Effects on the Cement Mantle – A Biomechanical Analysis of Femoral Stem Displacement during Implant Cementation

Background: It is a common notion that motion of a femoral component during cementation should be avoided as it may weaken the cement mantle. We created an in vitro model of cemented femoral components and subjected them to varying rotational motion during the cement curing process, to measure the effect on the pullout strength of the stem. Methods: 21 sawbones femurs were separated into four groups. The first group served as control and was cemented in a standard fashion. The remainder of the stems were divided into groups and subjected to angular rotational displacement within the cement mantle during curing . Anteroposterior and lateral radiographs were obtained of each model to evaluate for cement defects. Pullout strength testing was performed. Results: Despite rotational displacement, no cement defects were noted on imaging. The control stems showed an average pullout strength of 3735.79N. The experimental groups showed a trend for lower failure loads but it was not statistically significant (P=0.063). Of the 21 stems tested, three encountered cement mantle failure and associated stem pullout and the remainder failed by peripros-thetic fracture. Conclusion: Despite conventional thinking that rotational displacement during the cementing process leading to disruption of the cement mantle integrity, this was not borne out in our study. This should give surgeons confidence that in the set-ting of unintended rotational displacement of a femoral stem, returning the stem to its original position does not significantly compromise the integrity of the cement mantle or the pullout strength of the femoral implant. Small displacement of the femoral stem with prompt correction during cement curing does not cause evident cement mantle defects or a loss of femoral stem pullout strength.

POSITION OF HEADS OF TEMPOROMANDIBULAR JOINT IN PATIENTS WITH MALOCCLUSION

This article describes the assessment of the condition, symmetry of temporomandibular joint and timely diagnosis of its dysfunction based on to H. Gelb method in malocclusion. The objective of this study was to investigate the position and assess the symmetry of the temporomandibular joint heads according to H. Gelb in cases of malocclusion. Materials and мethods. The study was based on analysis of computed tomographs of 70 patients with malocclusion. Depending on the stage of the occlusion development, the patients were divided into two groups: I group included 30 patients with mixed dentition and II group included 40 patients with permanent dentition. Results. The results obtained demonstrated that regardless of the pathology of the occlusion and age, only 8 patients had the correct bite, i.e. the symmetrical position of the temporomandibular joint heads in the Gelb 4/7 position. The most frequent symmetric position of the articular heads in the patients of the I group I was the Gelb ¼ position found in 16 patients; the Gelb 1/5 position was revealed in 8 patients of the II group that can be explained as age-related changes in the displacement of the articular heads from the Gelb 1/4 to 1/5 position. Conclusions. According to the results of our research, it was found that regardless of the malocclusion and age, patients who have the correct position of the temporomandibular joint heads on the left and right in the Gelb 4/7 position make up only 10.52%. The age-related dynamics of the rotational displacement of the centre of the articular heads from the Gelb 1/4 to 1/5 position has been observed, and the number of patients with the asymmetric position of the temporomandibular joint articular heads is increaing.

Radial Neck Fracture With 180° Rotational Displacement in Pediatrics: A Case Report of a 6-Year-Old Child

Introduction: Radial neck fracture is one of the rare traumas in the upper extremity among the children accounting for 5%-10% of the pediatric elbow injuries. The valgus strain-induced radial neck displacement often ranges from 10° to 90. Rotational displacement with 180° rotation is very rare. Case Presentation: In this case report, we present a 6-year-old child who had radial neck fracture with 180 rotation and joint surface tilt toward the distal direction after falling on her outstretched hand. The close reduction was conducted under the fluoroscopic guide and the radial neck-shaft was restored with 15 angulation. The elbow was immobilized by a long forearm cast for 3 weeks. Based on conventional radiography taken after 3 weeks, a complete union was achieved. Six-month follow-up showed no radial growth disturbance and radial head avascular necrosis. Conclusions: The radial head could be displaced in the form of 180° rotation during the radial neck fracture. In this regard, careful attention to the joint surface is important to minimize the lateral displacements or angulation and to avoid any misdiagnosis. The closed reduction was a successful treatment and caused no complications.