Multiple Screws Research Articles

Algorithm for extracting the normal cross-section parameters of multiple ball screw shaft ball tracks based on an optical micrometer measurement system

Abstract The accurate and efficient measurement of the normal cross-section parameters of multiple ball screw shaft spiral ball tracks are pivotal for ensuring quality control in ball track machining. Given the intricate nature of the ball screw shaft spiral ball track, balancing the accuracy and efficiency of the normal cross-section parameters measurement is a significant challenge. In this study, we present a method to calculate two core parameters, arc radius and contact angle. The method consists of four parts: the automatic axial cross-section separation method, the arc symmetric extraction method, the spiral transformation method, and the parameter algorithm based on the weighted least squares method. The experimental and simulation results validated the effectiveness of our method. Compared with the traditional axial measurement and transformation (AMT) method, our algorithm reduced the errors in arc radius and contact angle by up to 13.9 µm and 4.77°, respectively, and improved the accuracy by up to 78.34% and 85.04%. Compared with the traditional AMT methods and directly normal measurement method, the measurement time of our algorithm was reduced by up to 1565 s and 3475 s, respectively, and the efficiency was improved by up to 71.01% and 84.51%, respectively.

Vertical Alveolar Ridge Augmentation using fixture-supported Titanium-mesh : Case Series

The vertical height of the alveolar bone and the amount of remaining bone are important factors in the long-term success of implants. If the remaining bone is insufficient, procedures such as vertical alveolar ridge augmentation, like guided bone regeneration, are necessary for ideal implant surgery. Among the non-resorbable membranes that can be used in these procedures, titanium mesh offers advantages such as maintaining space for bone grafting, protecting the underlying graft material, and allowing adjustment to match the defect site for desired shaping. However, fixation of titanium mesh, which is crucial in determining the overall success of the surgery, requires the use of multiple screws and may result in membrane exposure during the healing process. To overcome these problems, a recent development involves the use of fixture-supported titanium-mesh, which has demonstrated good results. This study suggests that vertical alveolar ridge augmentation using fixture-supported titanium mesh can resolve conventional problems and can be considered an effective and reasonable strategy for achieving ideal implants.

Comparison of dynamic compression system versus multiple cancellous screws in the treatment of femoral neck fractures in young adults

IntroductionFemoral neck fractures have posed a significant global healthcare challenge and had notable impacts on the quality of life. Current treatment strategies for femoral neck fractures in young individuals have varied, emphasizing the need for optimal fixation methods. This study compared the clinical and radiological outcomes of the dynamic compression system (DCS) and multiple cancellous screws (MCS) methods.MethodsThis retrospective study included a total of 275 young adults with fresh femoral neck fractures treated with DCS and MCS. A matching analysis with a 1:1 ratio based on age, gender, fracture classification, and reduction quality was conducted. Demographic data were recorded, and comparisons were made according to follow-up time (FUT), hospitalization period, operation duration, femoral neck shortening, caput-collum-diaphysis (CCD) angle, Harris Hip Score (HHS), and post-operative complications.ResultsA total of 42 fractures were matched with a median age of 42 years (range, 22–48). In the DCS group, vertical neck shortening (median 1.92) was significantly lower than that in the MCS group (median 4.53) (P < 0.05). In the DCS group, horizontal femoral neck shortening, resultant femoral neck shortening, the amount of change in CCD angle, and HHS were 0.57 mm (0.43, 4.74 mm), 1.82 mm (0.40, 3.53 mm), 0.13° (-0.78°, 1.80°), and 91 (85–93), respectively. They were all non-significant than 1.00 mm (0.56, 6.23 mm), 2.74 mm (1.59, 6.71 mm), -0.18° (-1.11°,1.85°), and 91 (75, 93) in the MCS group, respectively (P > 0.05). There was no statistical difference in FUT, hospitalization period, operation time, and post-operative complications at the latest follow-up (P > 0.05). There were no complications such as pulmonary embolism, deep vein thrombosis, and incision infection reported.ConclusionDCS and MCS demonstrated effectiveness in treating femoral neck fractures in young adults. The DCS implant provides additional stability in the vertical axis. A prospective randomized controlled study with a large sample size was needed to validate these findings.

Screw Configuration Does Not Significantly Alter Neck Shortening After Valgus-Impacted Femoral Neck Fracture (OTA Type 31B1.1).

To compare 3 different cancellous screw configurations used for Garden 1 femoral neck fractures (FNFs). Retrospective review. A large urban academic medical center. All patients with OrthopaedicTrauma Association 31B1.1 FNF who underwent in situ fixation with cancellous screws between 2012 and 2021 were included. Patients were divided into 3 groups: 2 screws placed in a parallel fashion, 3 screws placed in an inverted triangle configuration, and 3-screw fixation with placement of 1 "out-of-plane" screw perpendicular to the long axis of the femur. Postoperative femoral neck shortening (mm) was the primary outcome, which was compared among the 3 groups of different screw configurations. Sixty-one patients with a median follow-up of 1 year (interquartile range 0.6-1.8 years) and an average age of 72 years (interquartile range 65.0-83.0 years) were included. All fractures demonstrated bony healing. Overall, 68.9% of the cohort had ≤2 mm of femoral neck shortening. There was no difference between groups in the proportion of patients who experienced greater than 2 mm of shortening (P = 0.839) or in the amount (mm) of femoral neck shortening (Kruskal-Wallis χ2 = 0.517, P = 0.772). Although most patients with valgus-impacted FNF treated with screw fixation do not experience further femoral neck shortening, some patients demonstrated continued radiographic shortening during the healing process. The development of further femoral neck shortening and the amount of shortening that occurs do not differ based on implant configuration. Multiple different screw configurations seem to be acceptable for achieving healing and minimizing further femoral neck impaction. Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Multiple screw dislocations and a mode III Zener–Stroh crack in a nanowire

Multiple screw dislocations and a mode III Zener–Stroh crack in a nanowire

Arthrodesis for Eaton-Littler stage III degenerative trapeziometacarpal arthritis: a retrospective comparative study of fixation methods

Purpose: This study compared clinical outcomes depending on the fixation modality in patients who underwent arthrodesis surgery for Eaton-Littler stage III trapeziometacarpal (TM) joint arthritis between 2009 and 2022. Methods: In total, 39 patients with 44 hands (five patients had surgery on both hands) were selected. Depending on the operative fixation instruments, patients were divided into two groups: group 1, surgery with 25-gauge interosseous wiring and Kirschner wire or headless screw fixation; group 2, surgery with only multiple headless screws for fixation. Bone union was achieved at 62 days after surgery in group 1 and 75 days in group 2 (p=0.165). Results: The preoperative mean visual analogue scores improved during the postoperative outpatient follow-up period in both groups (group 1, from 4.0 preoperatively to 1.0 at the final follow-up; group 2, from 5.0 preoperatively to 2.0 at the final follow-up). Mean grip strength and pinch strength increased after surgery. One patient (4.8%) experienced nonunion in group 1, whereas nonunion occurred in four patients (17.4%) in group 2. This difference was not statistically significant. Four patients in group 1 and no patients in group 2 underwent fixation instrument removal after sound union. Conclusion: Adequate stability can be achieved during arthrodesis by combining interosseous wiring and other implants or multiple headless compression screws, resulting in successful outcomes for patients with Eaton-Littler stage III degenerative TM arthritis.

Comparison of the Surgical Outcome between the Multiple Screw Fixation and Fixed Angle Devices for the Basicervical Femoral Neck Fractures.

Introduction: Basicervical femoral neck fracture (FNF) is an uncommon type of femoral neck fracture and is associated with an increased risk of fixation failure due to its inherent instability. The purpose of this study was to compare the surgical parameters and reoperation rate between the use of a multiple cannulated screw (MCS) and fixed angle device (FAD) in treating basicervical FNFs. Methods: We retrospectively reviewed the records of 885 patients who underwent internal fixation between May 2004 and August 2019 to determine basicervical FNF with at least 12 months of follow-up. Among the identified 77 patients with basicervical FNF, 17 patients who underwent multiple cannulated screw (MCS) fixation and 36 patients who underwent fixed angle device (FAD) fixation were included. We compared the rates of fracture-site collapse and reoperations according to the fixation device. Results: Among the 53 patients with basicervical FNF, 13 patients (24.5%) sustained surgical complications (8 collapses of fracture site and 5 reoperations). The reoperation rate in the MCS group was significantly higher than that in the FAD group (23.5% vs. 2.8%, p = 0.016), without any significant difference in the collapse of the fracture site (11.8% vs. 16.7%, p = 0.642). Conclusions: Although basicervical FNF was rare among hip fractures, fracture site collapse was prevalent and prone to fixation failure. Surgeons should keep this in mind, and consider FAD for basicervical FNF.

Comparison of young femoral neck fractures treated by femoral neck system, multiple cancellous screws and dynamic hip screws: a retrospectively comparison study

BackgroundImplant choice for the fixation of femoral neck fracture is one of the most important management controversies. This study aims to evaluate and compare the short-term outcomes associated with the use of the Femoral Neck System (FNS), Multiple Cancellous Screws (MCS), and Dynamic Hip Screws (DHS) in treating femoral neck fractures in a young patient population.MethodsFrom June 2018 to June 2021, a total of 120 surgeries for a primary femoral neck fracture were retrospectively analyzed. This review encompassed demographic details of the patients and the mechanisms behind the injuries. Key surgical parameters such as operation duration, intraoperative blood loss, fluoroscopy duration, and hospital stay were meticulously documented. The employed surgical technique was described. All patients were followed up at 6 weeks, 3 months, 6 months, and 12 months postoperatively. Avascular necrosis of the femoral head (AVN), nonunion, malreduction, implant failure or other complications were noted. The functional status at the last follow-up was assessed using the Harris functional scoring criteria.ResultsThere were 90 males and 30 females, with a mean age of 40.4 years. As to patient characteristics, there were no significant differences between the three groups. DHS group showed longer operation time(52.15 ± 4.80 min), more blood loss(59.05 ± 5.87 ml) and longer time of hospitalization(7.6 ± 0.90 d) than FNS group (39.65 ± 2.84 min, 45.33 ± 9.63 ml and 4.87 ± 0.48 d) and MCS group (39.45 ± 3.10 min, 48.15 ± 7.88 ml and 5.04 ± 0.49 d) (p < 0.05). In addition, the time of fluoroscopy in FNS group (15.45 ± 3.67) was less than that in MCS group (26.3 ± 4.76) and DHS group (27.1 ± 5.67) (p < 0.05). The cost of FNS group(44.51 ± 2.99 thousand RMB) was significantly higher than the MCS and DHS groups. The FNS, MCS and DHS groups showed a similar mean length of femoral neck shortening (LFNS) and Harris score. The FNS, MCS and DHS groups showed a similar mean rate of AVN and internal fixation failure.ConclusionsFollowing successful fracture reduction, FNS, MCS, and DHS are effective for in the young femoral neck fractures. No difference was found in complications between the three groups. However, the reduced fluoroscopy time associated with FNS contributes to shorter operation durations. The adoption of minimally invasive techniques correlates with decreased blood loss and shorter hospital stays. Nevertheless, these advantages may be offset by the potential economic burden they impose.

Pelvic Fixation Construct Trends in Spinal Deformity Surgery.

Although many techniques exist, spinopelvic fixation continues to present challenges in the management of adult spinal deformity. Shear forces, complex anatomy, and bone quality are common reasons why spine surgeons continue to explore options for fixation. A retrospective chart reviewed of patients receiving pelvic fixation for adult spinal deformity over a 12-year period was conducted. Patients were divided into 3 cohorts based on date of surgery: (1) 2010 to 2013, (2) 2014 to 2017, and (3) 2018 to 2021. Pelvic fixation constructs in the study included traditional iliac screws, stacked S2-alar-iliac (S2AI screws), and triangular titanium implants. Of the 494 patients with multiple implant constructs who met the inclusion criteria for this study, patients undergoing pelvic fixation surgery who received at least 2 implants increased by approximately 5% every 4years (90.2%, 94.6%, 99.1% respectively). Over the 12-year span, the implementation of the S2AI screw grew 120%. At our institution, there is a trend toward using multiple bilateral implant constructs for pelvic fixation, with nearly a tenfold percentage increase between the most recent cohorts. These include iliac screws with S2AI screws, multiple stacked S2AI screws, and S2AI screws used in conjunction with triangular titanium implants in hopes to decrease implant failure.

Dynamic Locking Plate versus Multiple Cancellous Screws for the Fixation of Intracapsular Femoral Neck Fractures: Long-Term Results and Quality-Of-Life Assessment Based on Patient-Reported Outcome Measures.

The purpose of this study was to compare the long-term clinical outcomes and quality-of-life measures for two fixation methods in the setting of displaced femoral neck fractures. The two groups included fixation with multiple cancellous screws (group 1) and telescopic femoral neck screws and a small locking plate device (Targon FN) (group 2). Patients underwent reduction and internal fixation with either multiple cancellous screws or the Targon FN device from March 2000 to January 2012. Failure endpoints included nonunion, osteonecrosis of the femoral head, and revision surgery. Patient-reported outcome measures included chronic pain, ability to ambulate, and the use of ambulation assistive devices. Statistical analysis demonstrated a statistically significant lower rate of non-union and overall complication in the Targon FN group (p value < 0.001 and p value = 0.005, respectively). Logistic regression analysis showed that operative fixation with the Targon FN device decreased the odds ratio for overall complication by a factor of 0.34 (p = 0.02). There were no statistically significant differences between groups 1 and 2 in patient-reported outcomes (chronic pain (p = 0.21), ability to ambulate (p = 0.07), and the use of an ambulation assistive device (p = 0.07)). When compared to traditional cancellous screw fixation of femoral neck fractures, the Targon FN device has significantly lower complication rates and equivalent patient-reported outcomes.

Displaced intra-articular calcaneal fractures treated with Calcanail® and additional screw fixation of the thalamic surface through lateral subtalar arthroscopy

The treatment of displaced intra-articular calcaneal fractures is not standardized, as many surgeons prefer not to perform surgery, considering a high rate of cutaneous complications associated with the usual extensile lateral approach. The Calcanail® represents a percutaneous osteosynthesis device that is biomechanically more stable than multiple screws or locking plates. While it effectively restores the height and axis of the hindfoot, it appears to be less reliable in achieving articular reduction of the thalamic surface in cases of mixed fractures. Therefore, we developed a new technique suitable for comminuted mixed fractures, using the Calcanail® device with an arthroscopically guided closed reduction internal fixation of the thalamic surface.

Postoperative Valgus Deformity and Progression of Ostheoarthritis in Non-Displaced Femoral Neck Fractures.

Nondisplaced femoral neck fractures have traditionally been treated with in situ fixation. However, poor surgical and clinical outcomes have been reported for fractures with valgus deformity >15°, and the reduction of valgus impaction has recently been emphasized. In addition, early degenerative osteoarthritis can be caused by cam-type femoroacetabular impingement after healing of femoral neck fractures. This study was designed with the objective of confirming the difference in progression of radiographic osteoarthritis according to the severity of the valgus deformity. Patients who underwent internal fixation using multiple cannulateld screws for management of nondisplaced femoral neck fractures were divided into two groups: high valgus group (postoperative valgus angle ≥15°) and low valgus group (postoperative valgus angle <15°). Evaluation of demographic data and changes in the joint space width from the immediate postoperative period to the latest follow-up was performed. A significant decrease in joint space width in both hip joints was observed in the high valgus group when compared with the low valgus group, including cases with an initial valgus angle less than 15° and those corrected to less than 15° of valgus by reduction. No complications requiring surgical treatment were observed in either group; however, two cases of avascular necrosis, one in each group, which developed in the low valgus group after reduction of the fracture, were followed for observation. Performing in situ fixation in cases involving a valgus deformity ≥15° in non-displaced femoral neck fractures may cause accelerated narrowing of the hip joint space.

A Novel Multiple Screw Distraction Reducer System in the Treatment of Scoliosis with a Severe Rib Hump.

The treatment of scoliosis with a severe rib hump remains a major challenge. Traditional vertebral rotation techniques are not satisfactory, and thoracoplasty has many pulmonary complications that limit its application. A novel surgical device, the multiple screw distraction reducer (MSDR) system, provides longitudinal distraction during the corrective operation while at the same time providing lateral translation and axial derotation, which may facilitate the correction of a rib hump. This study was performed to investigate the effectiveness of the MSDR system for adolescent idiopathic scoliosis (AIS) with a severe rib hump. This was a case-matched study of patients with retrospectively collected data from our hospital between January 2017 and December 2021. Sixty-eight patients who underwent one-stage posterior pedicle screw-instrumented spinal fusion were matched by the Cobb angle of the main curve and rib hump. All patients underwent a minimum of 2 years of follow-up. The patients were divided into two groups: the MSDR group (using the MSDR system, n = 34) and the DVR group (using direct vertebral derotation, n = 34). The patients were evaluated for the height of the rib hump, deformity correction, complications, and SRS-30 scores. The unpaired Student's t-test and Pearson's χ2 -test were used to compare the outcome measures between the two groups. Multiple linear regression analysis was used to examine the variables that affected the correction of a rib hump. The rib hump was 30.21 ± 6.21 mm versus 29.35 ± 6.52 mm (p = 0.583) preoperatively and 9.18 ± 4.06 mm versus 13.82 ± 5.54 mm (p < 0.001) at the last follow-up in the MSDR and DVR groups, respectively. The correction rates were 70.83% and 53.56%, respectively (p < 0.001). Preoperatively, the main thoracic curve was 58.43° ± 7.97° and 57.84° ± 6.32° (p = 0.736) and was corrected to 10.92° ± 5.47° and 19.14° ± 5.32° (p < 0.001) at last follow-up in the MSDR and DVR group, respectively. Thoracic kyphosis was restored from 18.24° ± 5.19° and 17.98° ± 5.28° (p = 0.836) in the MSDR and DVR group to 24.59° ± 4.41° and 19.32° ± 4.96° (p < 0.001), respectively. Correction of apical vertebra rotation and translation in the main thoracic curve were significantly better in the MSDR group than in the DVR group (p < 0.05). There was no significant difference in the Lenke type, implant density, estimated blood loss, or follow-up duration between the two groups, whereas the operation time in the DVR group was significantly less than that in the MSDR group. There were only two minor pulmonary complications in the MSDR group. At the last follow-up, the MSDR group scored higher in terms of appearance and satisfaction (p < 0.05). The MSDR system, enabling better coronal alignment, thoracic kyphosis, and axial derotation, could be a safe and effective technique for severe rib hump correction in AIS.

An efficiency calculation model for ball screws by accounting for lead errors

Transmission efficiency is a pivotal indicator, providing a comprehensive view of the overall performance of a ball screw. While extensive research has predominantly focused on computing transmission efficiency across various operating conditions, the factors influencing the variability have often been overlooked. This study introduces an innovative method for computing transmission efficiency, which considers lead error, drawing on deformation coordination theory and load distribution. Multiple ball screws of varying precision grades underwent rigorous testing to quantify lead errors. Subsequently, each screw was matched with an identical set of nuts to measure the respective transmission efficiencies. Experimental results reveal a linear correlation between lead error and transmission efficiency when both lead error and uneven ball load distribution in ball screws are considered. The relative error between the calculated transmission efficiency results and experimental values for ball screws of different precision grades falls within the range of 0 % to 7.42 %, confirming the validity of the proposed model in this paper.

Lignocellulosic biomass pretreatment: Industrial oriented high-solid twin-screw extrusion method to improve biogas production from forestry biomass resources

Forestry lignocellulosic waste is an important, largely untapped source of biomass for producing clean energy. In this study, a high-solids twin-screw extrusion approach is developed as a novel pretreatment method to effectively increase the biogas production rate to better fit commercial requirements. Multiple screw designs are progressively introduced with increasingly intensified mechanical shear. The experiments also looked at the impact of feed solids content and several cost-effective processing aids along with these screw designs. Various characterization methods were used to relate the physical state of the biomass based on its specific surface area and volatile fraction, to the rate of biomethane generation possible from a 14- and 31-day biomethane potential test. An increase in biomethane production over this period by up to 190% was possible with the optimal screw design compared to a benchmark sample. This is a promising finding for the industrialization of biomethane production from forestry lignocellulosic biomass.

Characteristics and Treatment Strategies for Basicervical and Transcervical Shear Fractures of the Femoral Neck.

This study aimed to define basicervical and transcervical shear fractures using area classification and to determine the optimal osteosynthesis implants for them. The clinical outcomes of 1042 proximal femur fractures were investigated. A model of the proximal femur of a healthy adult was created from computed tomography images, and basicervical and transcervical shear fractures were established in the model. Osteosynthesis models were created using a short femoral nail with a single lag screw or two lag screws and a long femoral nail with a single lag screw or two lag screws. The minimum principal strains of the fracture surfaces were compared when the maximum loads during walking were applied to these models using finite element analysis software. Basicervical fractures accounted for 0.96% of all proximal femur fractures, 67% of which were treated with osteosynthesis; the failure rate was 0%. Transcervical shear fractures accounted for 9.6% of all proximal femur fractures, 24% of which were treated with osteosynthesis; the failure rate was 13%. Finite element analysis showed that transcervical shear fracture has high instability. To perform osteosynthesis, multiple screw insertions into the femoral head and careful postoperative management are required; joint replacement should be considered to achieve early mobility.

Outcomes After Hallux Interphalangeal Joint Arthrodesis.

Hallux interphalangeal joint arthrodesis (HIPJA) is indicated for a variety of pathologies. Despite high nonunion rates, techniques remain unchanged. The aim of this study is to examine nonunion and complication rates and describe risk factors for treatment failure. A query of an institutional database was performed to identify all patients undergoing HIPJA procedure over a 10-year period. Records were reviewed to the procedure, evaluate patient factors, indications, and radiographic/clinical arthrodesis. Radiographic union was defined as 2 cortical continuations or bridging at the arthrodesis site, absence of hardware failure, and the absence of lytic gapping of the arthrodesis. Clinical fibrous union was defined as radiographic nonunion with painless toe range of motion and physical examination consistent with fusion across the interphalangeal joint. Two hundred twenty-seven primary HIPJA procedures were identified. Our cohort demonstrated a 25.5% nonunion rate (58/227) and 21.1% reoperation rate (48/227). Patients with diabetes were at higher risk for nonunion (P = .014), but no significant differences were identified based on smoking status or diagnosis of inflammatory arthritis. No difference was seen between implant groups: single screw, multiple screws, screw plus other fixation, nonscrew fixation. Patients with prior hallux metatarsophalangeal joint arthrodesis did not have a significantly higher nonunion rate than patients without prior first metatarsophalangeal joint arthrodesis. Patients diagnosed with radiographic nonunion were at higher risk for reoperation (P < .0001). Our cohort represents the largest single-center series of HIPJA procedures published to date. We found relatively high nonunion and reoperation rates with standard current techniques. Level III, retrospective case series.

Thermal degradation and performance evolution mechanism of fully recyclable 3D printed continuous fiber self-reinforced composites

An innovative recycling method that does not require separation of the reinforcement and matrix is been proposed based on 3D printing of continuous fiber self-reinforced composites. The continuous fiber self-reinforced polyphenylene sulfide (PPS) composites were mechanically ground and directly remanufactured by screw extrusion 3D printing. The recycling procedure was accelerated and the thermal processing of the material was reduced. This recycling paradigm of self-reinforced composites with in-situ resource utilization is ideally suited to the space environment. The recycled self-reinforced composites showed no significant loss in tensile properties and even exhibited a slight increase after multiple recycling cycles owing to the melted PPS fiber in comparison with original PPS matrix. Since recycled material didn't separate the fiber from the matrix, its flexural strength and modulus increased by 34.11% and 51.81%, respectively, when compared to original PPS matrix. Molecular structure, rheological changes, and crystallization behavior were systematically investigated to elaborate the thermal degradation mechanism of recycled composites. The results obtained from systematical characterizations indicated that the recycled composites formed the cross-linking structure when subjected to multiple screw extrusion processing. The energy consumption of the screw extrusion-based 3D printing method was also conducted. The total energy intensity of recycling and remanufacturing processes were only about 17.9 MJ/kg. Spatial suitability, considering the advantages of self-reinforced composite recycling for space applications, were analyzed. Finally, theoretical material recovery rate of 100% for self-reinforced composites opens the prospect to reduce maintenance logistics in space. A future application scenario for fully recyclable self-reinforced composites in space was explored.

The Feasibility of Multiple Fixation Points in C2.

Analysis using three-dimensional simulation software for spinal screw placement and computed tomographic scan images. To assess the feasibility of achieving multiple (three or four) screw fixation points in C2 vertebra by using a combination of pedicle and laminar screws. Secure C2 fixation using multiple screws is required or beneficial in some unique cases. However, to the best of our knowledge, there have been no reports analyzing the feasibility of multiple screw fixation in C2. We used 1.0-mm interval computed tomographic scan images of 100 patients (50 men and 50 women) and screw trajectory simulation software. The diameter of all screws was set at 3.5 mm, considering its common usage in real surgery. The anatomical feasibility of placing both pedicle and laminar screws on the same side was evaluated. For all feasible sides, the three-dimensional distance between the screw entry points was measured. In 85% of cases, both pedicle and laminar screws could be placed on both sides, allowing for the insertion of 4 screws. In 11% of cases, 2 screws could be placed on one side, while only 1 screw was feasible on the other side, resulting in the placement of 3 screws. In all 181 sides where both types of screws could be inserted, the distance between their entry points exceeded 16.1 mm, which was sufficient to prevent the collision between the screw heads. C2 vertebra can accommodate three (11%) or four (85%) screws in 96% of cases.

Study of outcome of displaced calcaneal fractures by closed reduction and percutaneous internal fixation with multiple k wires and screws

Background: Calcaneum is the largest of the tarsal bones and the largest bone of the foot. Calcaneum fracture account for 2% of all fracture of the body and 60% of all tarsal fractures. Many calcaneal fractures are work related as they result from a fall from height, especially in male age 35-45 years. In our study we treated the displaced calcaneal fracture with closed reduction and percutaneous fixation using multiple percutaneous K-wires and screw to evaluate their functional outcome. Methods: The study was conducted as a prospective study at the department of Orthopaedics, Dr. Shankarrao chavan Government Medical College, Nanded, India during the period January 2019 to June 2020. Thirty patients of 20 to 60 years, who underwent surgical fixation for displaced calcaneal fracture using multiple K wires and screws were followed up. Functional outcomes at six month follow up were assessed. Results: In this study we selected 30 patients with displaced calcaneal fracture admitting in our institute. All patients underwent operative procedure in the form of multiple k wire and cc .screws by percutaneous approach Out of all 30 patients treated with this method had shown excellent results with minimal postoperative complications. Conclusions: The study with percutaneous K wires and screws for displaced calcaneal fractures showed very good functional outcome. Although it was not free of complications, our study has shown very good results. Technique involve in our study is less invasive, with minimum blood loss, less operative time without soft tissue stripping.