Bicortical Screw Fixation Research Articles

Background: Jones fractures of the 5th metatarsal are frequently associated with nonunion due to limited vascularization and repetitive mechanical stress. The aim of the study was to compare the biomechanical performance of T-plate and bicortical screw fixation using standardized 3D models. Methods: Three-dimensional models of the 5th metatarsal were generated from CT images and printed using PolyJet technology (Stratasys J5 DentaJet) using a rigid-elastic composite with properties similar to cortical and cancellous bone. Jones fractures were fixed with either a locked T-plate or a bicortical screw. The samples were tested under axial and oblique static loads (α = 0°, 90°, 180°) and for three values of interfragmentary distance (d = 0.1–1 mm), in a 3 × 2 factorial design. Results: The T-plate fixation recorded a maximum yield force (Fmax) of 149.78 ± 8.53 N (138–161 N), significantly higher compared to the bicortical screw −98.56 ± 2.58 N (96–101 N), (p < 0.05). The ductility index was higher for the plate, indicating a progressive transition to yield. The α and d factors significantly influenced the mechanical behavior, with the polynomial model explaining over 95% of the total variation. Discussion: The plate fixation demonstrated greater strength and superior biomechanical tolerance in imperfect reduction scenarios. The main limitation is the lack of fatigue testing and the inability of 3D models to reproduce the structural heterogeneity of human bone. Conclusions: Implant selection should be individualized based on fracture stability. 3D models provide a reproducible platform for comparative evaluation of osteosynthesis methods, but future studies should include cyclic loading and biological validation.

This study aimed to evaluate the stability of bimalleolar ankle fracture fixation techniques (bicortical and unicortical lag screw) in simulated progressive rehabilitation with a walking boot. Five matched pairs of lower extremities underwent simulated bimalleolar ankle fracture and were randomly assigned into these 2 repair groups. Each specimen was tested under an axial compression cyclic load test for 10000 cycles at a rate of 1 Hz while the ankle was held in 30° inclination. Radiographic assessments (screw attached lengths [length from screw head to far cortex], fracture gap, and joint clear space [medial, superior, and lateral]) by 3 examiners were performed at 0th, 5000th, and 10000th cycles. Three repeated measurements by each examiner. The overall level of intra-rater reliability for all 3 raters and all measurements were found to be within "moderate" to "excellent" agreement. For radiographic screw loosening and fracture displacement, evaluation found that at no time point did either the bicortical group or the unicortical group meet the minimal threshold of clinical failure which defined as 2-mm of screw displacement or 2-mm of fracture displacement. Both bicortical and traditional unicortical lag screw fixation techniques provide equivalent stability for medial malleolar fractures in a bimalleolar ankle fracture during simulated progressive rehabilitation with a walking boot. This could potentially have clinical benefits in patient care with earlier return to function, prevention of stiffness and loss of range of motion, and decreased muscle atrophy during the postoperative rehabilitation period.Level of Evidence: Level V: bench top testing.

Introduction: Accurate knowledge of cervical vertebral body dimensions is essential for effective diagnosis and treatment of cervical spine disorders. The anteroposterior diameter is a critical measurement for anterior bicortical screw fixation. Vertebral osteophytes, commonly seen on the anterolateral margins of the lower cervical vertebrae, are age-related degenerative changes that may cause neurovascular compression. Large osteophytes can compress the vertebral artery as it crosses the uncinate process, potentially resulting in dysphagia, sleep apnea, or spinal nerve root compression. Objectives: To assess the morphometric dimensions of the vertebral body and pedicle in typical cervical vertebrae and to observe the presence of osteophytes. Materials and Methods: This study was conducted on 100 dry human typical cervical vertebrae of unknown age and sex. Morphometric parameters of the vertebral body and pedicle were measured using a digital vernier calliper in millimeters. Measurements included anteroposterior and transverse dimensions. Results: The average vertebral body length was 14.55 ± 2.14 mm; anterior height 9.99 ± 1.35 mm; posterior height 11.1 ± 1.4 mm; superior width 21.61 ± 2.81 mm; and inferior width 19.58 ± 3.2 mm. Pedicle length and height were statistically significant, whereas pedicle width was not. Osteophytes were observed on the vertebral bodies. Conclusion: Morphometric data are valuable for surgical planning in anterior cervical reconstructi

Background: Relapse following sagittal split osteotomy is more common in mandible advancement surgeries. The dynamic action of masticatory muscle attached proximal to osteotomised bone plays an important role paving necessity for a rigid stable fixation. Objective: The aim of this study is to assess the efficacy of bicortical screws and sliding plates after Bilateral Sagittal Split Osteotomy for rigid fixation of osteotomised segments. Methods: The study included two groups (group A and group B) who underwent BSSO to correct their mandibular discrepancy. Group A consisted of (10 patients) who had osteosynthesis using Sliding Split Fix Plates (SYNTHES®, GERMANY), Group B consisted of (10 patients) who had osteosynthesis using Bi- cortical screws (BIOMET®). Skeletal relapse was assessed on 1st month, 3rd month, and 6th month post operatively. Series of lateral cephalogram was taken at the time of follow up and compare with pre op radiograph. Statistical analysis for relapse was done by Mann Whitney test. The P value is 0.99 which was not significant in linear dimension. Results: The relapse percentage assessed after one-year post surgery in Group A [patients with sliding split fix plates] along Sn-v axis was 14.42 %, and 21.5% was observed along 0-meridian. In Group B [Bicortical screws] along Sn-v axis the relapse percentage was 9.68% and 10.85% along 0-meridian. Conclusion: Based on the interpretation of study results, the maximum intercuspation in molar region was achieved in Bicortical screw fixation when compared to sagittal split fix plates. The percentage of relapse in bicortical screw fixation is lesser when compared with sagittal split fix plates.

The effect of the central post and screw constructs on the Univers Revers Total Shoulder System.

Unicortical Versus Bicortical Screws for Dorsal Plate Fixation of Phalangeal Fractures.

Ankle fractures continue to increase in incidence and severity in an older, more challenging geriatric population. Medial malleolus fixation with partially threaded cancellous 4.0-mm screws, a common fixation method, has been shown to fail due to pullout strength. Subsequent cadaveric models have shown increased pullout strength with the use of bicortical screws. The literature has also demonstrated fairly good clinical results with the use of bicortical screw fixation in a general population as well as in a complicated patient cohort. We sought to compare bicortical fully threaded 3.5-mm screw fixation with unicortical partially threaded 4.0-mm fixation in medial malleolus fractures. The aim was to compare postoperative complications such as screw failure/loosening, nonunion, delayed union, painful hardware, time to union, and time to full weightbearing. Of 292 patients retrospectively reviewed, 126 were included following the inclusion and exclusion criteria. The data included 48 patients in the bicortical group and 78 in the unicortical group, with a mean ± SD combined age of 56.0 ± 18.0 years. Complications occurred in three patients (6%) in the bicortical screw fixation group and in six (8%) in the unicortical group, which did not reach statistical significance. These results show that medial malleolus fixation has an overall low complication rate of 7% total combined, which is comparable with the current literature. We demonstrated no significant differences in complications, weeks to ambulation, or time to union between bicortical and unicortical fixation.

BackgroundSacral screw loosening is a typical complication after internal fixation surgery through the vertebral arch system. Bicortical fixation can successfully prevent screw loosening, and how improving the rate of bicortical fixation is a challenging clinical investigation.ObjectiveTo investigate the feasibility of improving the double corticality of sacral screws and the optimal fixation depth to achieve double cortical fixation by combining the torque measurement method with bare hands.MethodsNinety-seven cases of posterior lumbar internal fixation with pedicle root system were included in this study. Based on the tactile feedback of the surgeon indicating the expected penetration of the screw into the contralateral cortex of the sacrum, the screws were further rotated by 180°, 360°, or 720°, categorized into the bicortical 180° group, bicortical 360° group, and bicortical 720° group, respectively. Intraoperatively, the torque during screw insertion was recorded. Postoperatively, the rate of double-cortex engagement was evaluated at 7 days, and screw loosening was assessed at 1 year follow-up.ResultsThe bicortical rates of the 180° group, 360° group, and 720° group were 66.13%, 91.18% and 93.75%, respectively. There were statistically significant differences between the 180° group and both the 360° and 720° groups (P < 0.05). However, there was no statistically significant difference between the 360° group and the 720° group (P > 0.05).The rates of loosening of sacral screws in the 180° group, 360° group, and 720° group were 20.97%, 7.35% and 7.81%, respectively. There were statistically significant differences between the 180° group and both the 360° and 720° groups (P < 0.05). However, there was no statistically significant difference between the 360° group and the 720° group (P > 0.05). The bicortical 360° group achieved a relatively satisfactory rate of dual cortical purchase while maintaining a lower rate of screw loosening.ConclusionManual insertion of sacral screws with the assistance of a torque measurement device can achieve a relatively satisfactory dual cortical purchase rate while reducing patient hospitalization costs.

Surgical management paradigms of spinal pathologies in the aging population carry inherent substantial risks, with surgical complications being more prevalent among patients with osteoporosis compared to those with normal bone mineral density. In this narrative review, we aim to highlight important clinical understanding and considerations in perioperative evaluation and management of patients elected to undergo spinal surgery. Osteoporosis is a well-defined risk factor for mechanical complications following spinal surgery, and as such, perioperative optimization of bone health in the setting of surgery for geriatric patients remains a critical research area alongside intraoperative surgical augmentation techniques. Surgical techniques to circumvent challenges with instrumentation of poor bone mineral density have included augmentation of pedicle screw fixation, including segmental bicortical screw fixation techniques, cement augmentation with fenestrated screws, or use of expandable pedicle screws to improve bone-implant interface. Judicious selection of treatment modalities and subsequent perioperative optimization is paramount to minimize surgical complications. Contemporary guidelines and evolving paradigms in perioperative evaluation, optimization, and management of the aging spine include the advent of quantitatively evaluating computed tomography (CT) via assessment of the magnitude of Hounsfield units. Prescribing pharmacotherapeutic agents and monitoring bone health requires a multidisciplinary team approach, including endocrinologists and geriatricians to coordinate high-quality care for advanced-age patients who require surgical management of their spinal disorders.

Jones fractures are common injuries that can be treated conservatively or surgically. However, the optimal treatment approach remains controversial. This study aimed to compare the clinical outcomes of conservative and operative treatments for Jones fractures and determine whether surgical treatment is necessary. A retrospective study was conducted on 69 patients with Jones fractures treated at our hospital. The patients were divided into 2 groups: conservative (C group; n = 46) and operative (O group; n = 23) treatments. Patients were followed up after 2, 6, and 12 weeks, and every 3 months thereafter. However, outpatient follow-ups were conducted between 8 and 10 weeks as needed. The mean follow-up period was 14.5 weeks (range, 12-24 weeks). In group C, the patients were treated with a non-weight-bearing cast for 4-6 weeks, followed by additional weight-bearing boot immobilization before returning to exercise. In group O, patients were treated surgically using a bicortical screw or intramedullary internal fixation. Time to radiologic union, clinical union, return to sports, visual analog scale (VAS), Foot Function Index-Revised Short Form (FFI-RS), and American Orthopedic Foot and Ankle Society (AOFAS) scores were evaluated. Sixty-nine patients were included in the analysis. There were statistically significant differences in the time to radiologic union and return to sports, VAS score in the second week, and FFI-RS score in the 12th week. In group C, favorable outcomes were observed in terms of the time to return to sports, VAS score in the second week, and FFI-RS score in the 12th week. Contrastingly, in group O, better results were observed in time to radiologic union. The AOFAS score was excellent at the final follow-up, with no significant differences between groups. Complication rates were 10.8% and 13% in groups C and O, respectively. Surgical treatment is sometimes necessary for Jones fractures, but conservative treatment should also be considered because of the favorable outcomes. Conservative treatment can be a good option for patients who are risk-averse and place a high value on fracture healing without surgery.

Objectives The incidence of femoral periprosthetic fractures (PPF) is rising. Vancouver type C PPFs compromise the majority type of fracture associated with high complication rates. The complexity of Vancouver C-type PPFs lies in the presence of the femoral stem in the proximal fracture fragment. This study compares the biomechanical performance of four plate fixation configurations to repair Vancouver type C periprosthetic femur fractures. Methods Six large adult 4th generation biomechanical low-density femur Sawbones instrumented with cemented femoral stems were used to conduct this study. A comminuted Vancouver-type C PPF was simulated and fixed with a plate. Four proximal fragment construct configurations were studied with combinations of unicortical screws, bicortical screws, and cerclage cable fixation. Constructs were loaded in axial compression and four-point bending, and the stiffness was calculated. Results Constructs with bicortical screw fixation had significantly greater stiffness than those with unicortical screw and cerclage cable fixation in axial and four-point bending loads. Constructs with cerclage cable and unicortical screw fixation had greater stiffness than ones with unicortical screw fixation. Conclusion Using bicortical screws in the proximal construct of Vancouver type C PPFs increases construct stiffness in axial and bending loads. Though controversial, using cerclage cables might have a place for construct augmentation when using only unicortical screws or a combination of unicortical and bicortical screws.

Comparison of five methods for locked-plate fixation of complex diaphyseal fractures

Biomechanical comparison of four different fixation methods in the management of Pauwels type III femoral neck fractures: Is there a clear winner?

Internal fixation using angle stable plates is the treatment standard in periprosthetic fractures around stable implants. To provide instant postoperative full weight-bearing, bicortical screw fixation is advisable but often surgically demanding. This work presents the first clinical results of the LOQTEQ® VA Periprosthetic Plate (aap Implantate AG, Berlin, Germany), a new plate system to simplify screw placement around implants. This plate system uses insertable hinges that allow for variable angle screw anchorage. Data of 26 patients with a mean age of 80 years and a mean follow-up of 13.9 months were retrospectively collected. Patients were clinically and radiologically examined. Bony union was achieved in 14 out of 15 patients with no signs of non-union or implant loosening. One patient, however, presented with implant failure. Clinical scores demonstrated acceptable results. Since the hinge plates are easy to apply, the first results are promising.

Bilateral sagittal split osteotomy is a routine procedure with predictable and well-known complications. The authors report a thitherto unreported complication of bilateral sagittal split osteotomy presenting as a postoperative sialocele of submandibular salivary gland tissue in the floor of the mouth. The sialocele was probably caused by overinstrumentation and injury to sublingual salivary tissues or Wharton's duct during bicortical drilling or screw fixation. This iatrogenic sialocele was managed conservatively with multiple aspiration and compression dressings. Although rare and unreported so far this complication may be included in the preoperative consent process.

A novel canine tibial plateau leveling osteotomy (TPLO) fixation device was recently developed with design features such as titanium alloy (TA) material, distal monocortical screw fixation, and a point contact undersurface specifically targeted to reduce surgical site infection rates by ensuring tissue perfusion under the plate. The strength of the novel TPLO construct was compared with that of a predicate stainless steel (SS) locking plate construct with bicortical screws in 16 paired cadaveric canine limbs. The mean loads to failure were 716.71 ± 109.50 N (range 455.69–839.69 N) and 629.50 ± 176.83 N (range 272.58–856.18 N) in the TA and SS groups, respectively. The average ratio of the loads to failure of the paired specimens was 1.18 (p = 0.031). No failure of the TA constructs involved the distal fixation with monocortical screws. Substantial mechanical equivalence of this novel TA monocortical/bicortical fixation construct to an established SS bicortical screw fixation construct is demonstrated. Clinical investigation of potential merits of this novel TA, monocortical/bicortical locking screw/plate system is now warranted.

Evaluation of internal fixation techniques for condylar head fractures: A finite element analysis and comparison

A novel instrument for the prevention of condylar torque in bilateral sagittal ramus osteotomy when using bicortical screw fixation

Finite element analysis. To determine and compare the biomechanical stability of the bicortical short C2 pars screw fixation for high-riding vertebral artery (HRVA) with the C2 pedicle screw and C2 translaminar screw fixation in finite element models. Fixation of C2 is technically demanding in the case of HRVA. However, there is no consensus on the alternative technique for the C2 screw fixation for HRVA in the literature. A finite element model of the upper cervical spine (C0-C2) with HRVA had been developed. C1 pedicle screw was applied at C1 by using notching technique. Bicortical short C2 pars screws, C2 pedicle screws, and C2 translaminar screws were used in each model. Then a vertical load of 50 N and a 1.5 Nm torque were applied to the C0 to simulate flexion, extension, lateral bending, and axial rotation respectively. Compared with C2 pedicle screw fixation, the bicortical short C2 pars screw fixation increased the range of motion by -1.45%, 2.13%, 62.0%, and 22.0% under flexion, extension, lateral bending, and axial rotation, respectively. However, the C2 translaminar screw fixation increased the range of motion by 43.6%, 17.8%, 423.4%, and 19.9%, respectively. In terms of the peak von Mises stress, compared with C2 pedicle screw fixation, bicortical short C2 pars screw decreased 46.1%, 41.6%, 71.3%, and -12.5% under flexion, extension, lateral bending, and axial rotation, respectively; C2 translaminar screw decreased -2.66%, -4.87%, 73.0%, and -10.1%, respectively. For a patient with HRVA, bicortical short C2 pars screw fixation provides sufficient stability and exhibited a smaller von Mises distribution on the screw-rod construct, indicating it could be an effective C2 internal fixation method for HRVA to promote C1-C2 stability and avoid the vertebral artery injury.Level of Evidence: N/A.

Modular diaphyseal anchor stems with locking screws in the hip revision with massive femoral defects