The Relation between the Radial Collapse and the Number of Metaphyseal Screws for Distal Radius Fractures

@#Introduction: The purpose of this study is the evaluation of radial collapse, based on the number of screws used in the metaphyseal region and by distal dorsal distance (DDD) and lunate facet distance (LFD) measurement. Materials and methods: Between 2015 and 2019, 60 patients who were being treated with volar locking plates due to isolated distal radius fracture were evaluated. Control radiographs were taken on the first day and at 3rd-, 6th- and 12th-month follow-ups. Distal dorsal cortex distance and lunate facet distance were measured in the lateral radiographs. The number of screws used in the metaphyseal region was also evaluated. According to the number of screws, the amount of collapse was analysed based on both the LFD and the DDD. Results: The mean age of patients was 43.5±12.7 years. Thirty-three of the patients included in the study were male and 27 were female, and the minimum follow-up period was one year. According to the mean number of screws, groups were defined as up to 6 screws or 7 screws and above. There was a statistically significant difference between the groups in terms of DDD collapse at the 6th-month and 12th-month follow-ups (p<0.005). It was observed that the radial collapse and decrease in DDD and LFD were lower in plates with seven screws and above. Conclusion: Decreases in either DDD or LFD, or radial collapse were observed less in patients who had seven or more metaphyseal screws inserted. These findings might be useful for surgeons treating distal radius fractures to reduce radial collapse.

Finite element analysis of locking screw assisted acetabular cup fixation / 中国组织工程研究

BACKGROUND: The main reason for the failure after total hip arthroplasty is aseptic loosening of the prosthesis. The traditional acetabular cup fixation method is still controversial in maintaining the initial stability of the acetabular cup. It is a new method that can be considered to further improve the fixation method of the acetabular cup to increase its stability. OBJECTIVE: To analyze the feasibility and superiority of locking screw assisted acetabular cup fixation. METHODS: The digital model of acetabular cup and screws were reconstructed and assembled by software Solidworks. The Von-Mises and shear stress of the acetabular cup and screw by three methods, including acetabular cup, acetabular cup with ordinary cancellous bone screw, and acetabular cup with locked cancellous bone screw, were compared. RESULTS AND CONCLUSION: (1) The finite element model of the established acetabular cup and screw had excellent geometric similarity and could be used for finite element analysis. (2) The acetabular cups with locking screws received less Von-Mises and shear stress than other methods. (3) The locking screws could bear higher stress than ordinary screws and effectively dispersed the shear stress of acetabular cups. (4) It is concluded that the combination of locking screws to fix the acetabular cup can effectively prevent the instability of the acetabular cup and the loosening of the prosthesis; it can better provide stability for the acetabular cup and the mechanical environment that the bone tissue grow in the later stage. The acetabular cups with locking screws have obvious advantages than other ordinary screw, which has the limited bearing capacity and low anti-acetabular cup shear force.

Effects of Locking Screws with Different Head Angles on Mechanical Properties of Screw-Plate System / 医用生物力学

Objective To investigate the effects from head angle and locking times of locking screws on mechanical properties of the screw-plate system, so as to provide a theoretical basis for doctors to select appropriate locking screws and master the locking times in clinical surgical procedure. Methods Locking screws with different head angles were selected to match with locking compression plates in the case of different locking times, and cantilever bending method was used to compare the differences of mechanical properties in each group. Results There were significant differences in failure load and bending stiffness between locking compression plate and locking screw with different head angles (P0-05). The failure modes of locking screw with different head angles and different locking times were different, and the failure mode of locking screw had a positive correlation with its head angle and locking times. Conclusions The differences in mechanical properties between locking screw with different head angles and locking compression plate cannot be neglected. It is suggested that doctors should choose locking screw and locking compression plate with the best locking degree in clinical procedure, and choose the right torque wrench to lock in multiple times if necessary, thus to prevent screw loosening from affecting recovery of the patients.

Efficacy of dynamic locking screw combined with plate internal fixation for tibial fractures / 中华创伤杂志

Objective To evaluate the efficacy of dynamic locking screw combined with plate internal fixation for tibial fractures.Methods A retrospective case-control study was conducted to analyze the clinical data of 36 patients with tibial fractures(AO 4A-C)admitted to the Second Affiliated Hospital of Army Medical University from March 2017 to March 2018.There were 27 males and nine females,aged 26-71 years [(51.6±14.3)years].A total of 18 patients were treated with dynamic locking screw combined with locking plate internal fixation(Group A),and another 18 patients received common locking screw combined with locking plate internal fixation(Group B).The operation time,intraoperative bleeding,hospital stay,visual analogue score(VAS),callus growth and fracture healing rate at 4,8,12 and 24 weeks after operation were compared between the two groups.At the same time,the complications of internal fixation were evaluated,including screw loosening,screw fracture and steel plate fracture.Results All the patients were followed up for 8-18 months [(12.2±2.7)months].There was no significant difference in operation time,intraoperative bleeding,postoperative hospital stay and postoperative V AS between the two groups(P＞0.05).At 8 and 12 weeks after operation,the callus growth rate of Group A was 61％and 83％respectively,significantly higher than those of Group B(28％and 50％)(P＜0.05).At 8,12,and 24 weeks after operation,the fracture healing rate of Group A was 17％,50％and 100％respectively,and those of Group B was 6％,28％and 89％,showing no significant difference between the two groups(P＞0.05).No complications or failure of internal fixation were found during the follow-up.Conclusion For tibial fractures,the locking plate internal fixation can achieve satisfactory,clinical outcome,but the dynamic locking screw system can promote the growth of callus at early stage.

Efficacy of dynamic locking screw combined with plate internal fixation for tibial fractures / 中华创伤杂志

Objective@#To evaluate the efficacy of dynamic locking screw combined with plate internal fixation for tibial fractures.@*Methods@#A retrospective case-control study was conducted to analyze the clinical data of 36 patients with tibial fractures (AO 4A-C) admitted to the Second Affiliated Hospital of Army Medical University from March 2017 to March 2018. There were 27 males and nine females, aged 26-71 years [(51.6±14.3)years]. A total of 18 patients were treated with dynamic locking screw combined with locking plate internal fixation (Group A), and another 18 patients received common locking screw combined with locking plate internal fixation (Group B). The operation time, intraoperative bleeding, hospital stay, visual analogue score (VAS), callus growth and fracture healing rate at 4, 8, 12 and 24 weeks after operation were compared between the two groups. At the same time, the complications of internal fixation were evaluated, including screw loosening, screw fracture and steel plate fracture.@*Results@#All the patients were followed up for 8-18 months [(12.2±2.7)months]. There was no significant difference in operation time, intraoperative bleeding, postoperative hospital stay and postoperative VAS between the two groups (P>0.05). At 8 and 12 weeks after operation, the callus growth rate of Group A was 61% and 83% respectively, significantly higher than those of Group B (28% and 50%) (P<0.05). At 8, 12, and 24 weeks after operation, the fracture healing rate of Group A was 17%, 50% and 100% respectively, and those of Group B was 6%, 28% and 89%, showing no significant difference between the two groups (P>0.05). No complications or failure of internal fixation were found during the follow-up.@*Conclusion@#For tibial fractures, the locking plate internal fixation can achieve satisfactory clinical outcome, but the dynamic locking screw system can promote the growth of callus at early stage.

Pseudoaneurisma de arteria femoral asociado a fístula arteriovenosa producido por tornillo de bloqueo distal / Femoral artery pseudoaneurysm associated with arteriovenous fistula caused by distal locking screw Abstract

Femoral artery pseudoaneurysm associated with arteriovenous fistula is a complication of endovascular interventional procedures. However, no cases have been described in which both lesions occur as the result of trauma surgery and specifically that they are side effects to the placement of a gamma nail in the femur with a distal locking screw. We describe the case of a patient who presented femoral artery pseudoaneurysm concomitant with arteriovenous fistula, in which there were no suspicious clinical signs. The diagnosis was established using computed tomography, confirmed by arteriography and treated with the placement of metallic coils.

El pseudoaneurisma de arteria femoral asociado a fístula arteriovenosa es una complicación de los procedimientos intervencionistas endovasculares. Sin embargo, no se han descrito casos en los que ambas lesiones se produzcan como consecuencia de cirugía traumatológica y, en concreto, que sean secundarias a la colocación de clavo gamma en fémur con tornillo de bloqueo distal. Se describe el caso de una paciente que presentó pseudoaneurisma de arteria femoral concomitante con fístula arteriovenosa, en la que no existieron signos clínicos de sospecha. El diagnóstico se estableció mediante tomografía computarizada, se confirmó con arteriografía y se trató mediante la colocación de coils metálicos.

Failure of Removal of Stripped Locking Screw after Locking Compression Plating

PURPOSE: The purpose of this study was to evaluate the incidence and possible causes of stripped locking screws that make difficult to remove the locking compression plate. We also tried to find the useful methods to remove the stripped locking screws. MATERIALS AND METHODS: Between May 2005 and January 2009, 84 patients who underwent operations for removal of locking compression plate were included in this study. We removed 298 3.5-mm locking screws and 289 5.0-mm locking screws in these patients. We retrospectively investigated the incidence and possible causes of stripped locking screws and evaluated the pros and cons of the methods that we have used to remove the stripped locking screws. RESULTS: 17 out of 298 3.5-mm locking screws (5.7%) and 2 out of 289 5.0-mm locking screws (0.7%) were encountered with difficulties by hexagonal driver during removal because of the stripping of the hexagonal recess. First we used the conical extraction screw for all the stripped locking screws and only 3 screws were removed successfully. We removed 3 screws by cutting the plate around the stripped locking screw and twisting the plate with the screw and we removed 1 screw by the use of hallow reamer after cutting the plate. Twelve screw shafts were left except grinding of screw head by metal-cutting burr. There was one iatrogenic re-fracture in whom we have used with hallow reamer. CONCLUSION: At the time of locking compression plate removal, difficulties of locking screw removal due to the stripping of the hexagonal recess should be expected and surgeon must prepare several methods to solve this problem.

Anterior Cervical Fusion with New Angled Locking Screw for Cervical Spine Injury: Preliminary Report

Although anterior cervical plates provide excellent fixation for the anterior column, the potential risk for injury to the spinal cord or soft tissue has been the reason why they have not gained universal acceptance, new angled locking screw was designed to avoid such surgical complications. We are intending of anterior cervical fusion by means of new angled locking screw Orion Plate and also suggest that Orion Plate System is mandatory for reducing technical demands and late instrumentation failure.