Screw Fracture Research Articles

Efficacy of percutaneous pedicle screws for thoracic and lumbar spine fractures compared with open technique.

The objective of this study is to compare percutaneous techniques (MIS) with the open technique in terms of angle correction, long-term maintenance and clinical results. The authors collected a prospective database of thoraco-lumbar fractures treated with posterior stabilization without fusion from 2013 to 2019. The statistical analysis has been carried out retrospectively. The patients were classified into Open and MIS group. To compare the two population, samples, treatments and mitigate the differences between the groups, the propensity score (PS) matching was used. One hundred and eight patients with thoraco-lumbar fractures were included. After performing the PS, 21 patients were obtained in the open group and 28 in the MIS group. For operative and perioperative parameters there were no differences in number of patients with posterior decompression, number of instrumented segments, number of total screws, operative time and complications. Postoperative hemoglobin was similar in both groups. However, in the open group a greater loss of hemoglobin was observed; as well as, higher analgesia requirements and length of stay. No statistically significant differences were observed in neurological status in both groups in the preoperative, postoperative period and at follow-up. The Cobb angle showed no differences at admission comparing both groups. A similar angle correction was observed with both surgeries, but in open surgery there was a statistically significant loss of correction. We observed in this study that the MIS technique for the treatment of thoracolumbar fractures is as effective as the open technique in terms of angle correction; and demonstrated that is better in its maintenance over time. Clinical results were at least as good as with the open technique.

Posterior spinal fixation using penetrating endplate screws in patients with diffuse idiopathic skeletal hyperostosis-related thoracolumbar fractures.

Diffuse idiopathic skeletal hyperostosis (DISH)-related vertebral fractures essentially require operative treatment due to severe fracture site instability and high potential risk of posttraumatic neurological deficit. However, the optimal surgical procedure remains unclear. The purpose of this study was to assess the efficacy of posterior spinal fixation with penetrating endplate screws (PESs) for DISH-related thoracolumbar fractures. The authors conducted a retrospective, single-center, observational study. They included data from 26 consecutive patients with DISH-related thoracolumbar fractures who were treated with posterior spinal fixation using either conventional pedicle screws (PS group, n = 8) or a combined PES technique (PES group, n = 18) between 2013 and 2019. Age, sex, BMI, bone mineral density, fracture level, use of antithrombotic drug, blood loss, operation time, fixation range, perioperative American Spinal Injury Association Impairment Scale score, implant failure, revision surgery, complications, and mortality were compared. The authors also evaluated screw loosening and bone healing on radiographs and CT scans. More patients had vertebral fractures in the lumbar spine in the PS group than in the PES group (3 vs 0; p = 0.019). Patients in the PES group had less blood loss (63 vs 173 ml; p = 0.048) and shorter range of fixation (5 vs 5.5 levels; p = 0.041). The screw loosening rate was significantly lower in the PES group than in the PS group (3% vs 49%; p < 0.001). Posterior spinal fixation using a PES technique may be an ideal surgical procedure for thoracolumbar fractures with DISH, providing more rigid and less invasive fixation than PS.

A Anchoring Technique Using Long Bent Rods for Open Reduction of Thoracolumbar Dislocation.

The purpose of this study was to evaluate the effectiveness of a novel surgical open reduction method for thoracolumbar dislocation. This study included a total of 15 patients of thoracolumbar dislocation. All patients underwent posterior thoracolumbar open reduction and fixation using this technique. Preoperative x-ray, computed tomography (CT), and magnetic resonance imaging were used to evaluate the dislocation. The American Spinal Injury Association grade of spinal cord injury before and afer the operation were record. All patients were followed up for 2 years, and x-ray, CT were used to observe postoperative reduction and fusion. Postoperative x-ray and CT images of all patients indicated good recovery of the spinal sequence, and no neurological deterioration or surgically related complications occurred. All patients were followed up for 2 years, no patients were lost to follow-up. During the follow-up period, x-ray and CT images showed no complications related to internal fixation such as fracture and loosening of screws and rods were found. A anchoring technique using long bent rods is a safe, simple, accurate, and easy to replicate and implement method, which can be applied in the surgical treatment for thoracolumbar dislocation.

How to Manage Complications Related to the Use of Intramedullary Screws in Metacarpal Fractures: Case Series

AbstractThe use of intramedullary screws has been increasing among hand surgeons in cases of metacarpal fractures due to their low morbidity, and because they minimize incisions and dissection, and require less tissue manipulation and deperiostization. However, there are few published articles on the complications that arise from its use. Therefore, the purpose of the current study is to present a series of cases of complications following the use of intramedullary screws in metacarpal fractures that required surgical intervention, and to describe the surgical technique used to solve them . Methods We performed a retrospective multicenter study in which we reviewed the clinical history, surgical descriptions and radiographs of the patients submitted to fixation of intramedullary compression screws for metacarpal fractures. We defined as complications infection, lesion to the extensor apparatus, bending of the implant, loss of reduction, hardware failure, malrotation, and non-union. Results Out of a total of 45 patients, we reported 3 cases of complication: 1 patient with loss of reduction, and 2 patients with bending of the implant. In the three cases, the screw was removed without complications, and the focus of the fracture was stabilized. Conclusion Intramedullary fixation with compression screws is increasingly being used for metacarpal fractures, with reports of low rates of complications. In the series of cases herein reported, the complications were solved without difficulty, and the patients showed a good recovery in hand function in the follow-up. Knowledge of the possible complications and their management enables us to provide more safety to the patient at the time of choosing this technique.

Comparison of effectiveness between plate and screw internal fixation in treatment of posterior malleolus fractures through posterolateral approach

To compare the effectiveness of posterior malleolus fractures treated by plate and screw internal fixation through posterolateral approach. The clinical data of 95 patients with posterior malleolus fractures who were admitted between January 2016 and December 2019 and met the selection criteria were retrospectively analysed. They were divided into plate group (44 cases, treated with posterolateral plate internal fixation) and screw group (51 cases, treated with posterolateral screw internal fixation) according to different treatment methods. There was no significant difference in general data between the two groups of patients such as age, gender, cause of injury, side of injury, ankle fracture or injury classification, time from injury to operation, and percentage of posterior ankle fracture area to the distal tibia articular surface ( P>0.05). The operation time, hospital stay, fracture healing time, and surgical complications were compared between the two groups. Imaging examinations (X-ray film, CT scan and reconstruction) were used to assess the reduction quality of ankle fracture, articular congruity, and re-displacement in ankle fracture. At last follow-up, the pain visual analogue scale (VAS) score was used to evaluate the patients' pain, and the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score was used to evaluate ankle joint function. Patients in both groups were followed up 6-30 months, with an average of 18.2 months. The operation time of the plate group was significantly longer than that of the screw group ( U=-2.040, P=0.041); there was no significant difference in hospital stay between the two groups ( U=-1.068, P=0.285). Incision swelling occurred in 2 cases in the plate group, sural nerve injury in 3 cases, and traumatic arthritis in 2 cases during follow-up. In the screw group, there were 1, 2, and 2 cases, respectively. The incidence of complications in the two groups (15.9% vs. 9.8%) was not significantly different ( P=0.372). All patients who underwent tibiofibular screw fixation underwent the removal of the tibiofibular screw before taking full weight bearing at 12 weeks after operation, and there was no screw fracture and retention. During the follow-up, there was no infection, re-displacement of fracture, delayed bone union or nonunion, and there was no significant difference in fracture healing time between the two groups ( t=0.345, P=0.731). There was no significant difference between the two groups of reduction quality of ankle fracture and articular congruity evaluation results ( P>0.05). At last follow-up, there was no significant difference in VAS score, AOFAS ankle-hindfoot score and evaluation grade between the two groups ( P>0.05). Both the plate and screw internal fixation through posterolateral approach can achieve satisfied effectiveness in the treatment of posterior ankle fractures with maintenance of fracture reduction, and recovery of ankle joint function. The screw internal fixation has the advantages of minimal invasion and shorter operation time.

The Role of Medial Buttress Plate Augmentation of Cannulated Screws in Unstable Femoral Neck Fractures: A Pilot Study

Background: About 20% of femoral neck fracture surgeries require re-operation. The use of medial buttress plate may reduce the reoperation rate. The purpose of this study is to examine the results of using the method of augmentation of the cannulated screws with medial buttress plate for treatment of unstable femoral neck fractures. Methods: This study included patients with femoral neck fractures of Pauwels type 2 and 3 in which closed reduction was not successful. The patients underwent open anatomical reduction and implantation of three screws, and then the medial placement of the buttress plate was performed. Patients were followed up after 2 weeks, 6 weeks, 3 months, and 6 months. Union and fracture healing and operative complications were assessed using plain radiography. Results: This study included 8 patients with Pauwels type 2 and 3 femoral neck fractures. All patients were men with the mean age of 38.0 ± 11.3 years. Re-hospitalization 30 days after surgery, surgical site infection, deep vein thrombosis (DVT), and deep infection were not observed in any of the patients. The angle between the neck and the femur shaft dramatically increased during the 6-month follow-up (P = 0.049). Union occurred in 6 (75%) patients after 6 months, while 2 patients were lost to follow up. Participants’ Harris Hip Score (HHS) had a significant improvement from 3 months to 6 months after surgery (P = 0.02). Conclusion: Augmentation of cannulated screws with medial buttress plate for unstable femoral neck fractures in patients has advantages in short-term clinical follow-up.

Prosthetic complications and patient satisfaction with maxillary polyether ether ketone hybrid prosthesis veneered with acrylic or composite resin for patients rehabilitated by “All on four” concept

Purpose: To evaluate prosthetic complications and patient satisfaction with maxillary polyether ether ketone (PEEK) hybrid prosthesis veneered with acrylic or composite resin for individuals restored by “All on four” implants Materials and methods: Six patients with edentulous maxilla opposing mandibular implant overdentures had four implants in-between maxillary antrums according to the All on four concept and full arch PEEK fixed restoration veneered with acrylic resin (control group). The study group comprised six patients who had four implants using the All on four protocol and full arch PEEK fixed restoration veneered with composite resin. For both groups, prosthetic complications and patient satisfaction using visual analogue scale were measures after one year. Results: There were no prosthesis fractures, cylinder fracture, abutment fracture, prosthetic screw fractures occurred in both groups. Crown fracture occurred significantly more in the composite group compared to the acrylic group (p=.046).. The composite group showed significant higher overall chewing and esthetics compared to the acrylic group. On the other hand, the acrylic group showed significant higher ease of cleaning than the composite group. No difference in mouth comfort and speech between groups was noted. Conclusion: Both acrylic and composite veneers for full arch PEEK fixed restoration can be used successfully for rehabilitation of patients with maxillary All on four concept as they achieve favorable prosthetic and patient satisfaction out comes. However, composite veneers may be advantageous in term of satisfaction with chewing and esthetics and acrylic veneers may be advantageous in terms of crown fractures and ease of cleaning.

Effect of Crown Height on the Screw Stability of Titanium Screw-Retained Crowns.

The aim of this in vitro study was to evaluate the effect of crown height on the screw stability of screw-retained titanium implant crowns subjected to cyclic loading conditions. Twenty-one implants with internal hex connections were placed in epoxy resin holders. Mandibular first molar screw-retained titanium implant crowns with UCLA type, crown-abutment connections were CAD/CAM fabricated. Seven crowns of 3 different heights (6 mm, 10 mm, and 14 mm) were made. The crowns were seated onto the implants and screws were tightened to 30 Ncm. The implants were clamped into holders and stepwise cyclic loads were applied to the occlusal surface at 30-degree angles to the long axes of the crowns. The detorque values were measured after each 5 million cycles. Before increasing the applied load, the crowns were secured with new screws and tightened to 30 Ncm. Failure times, survival estimates and detorque values were then analyzed. (alpha = 0.05). Crown height did not significantly affect detorque values. However, five 14-mm crowns failed with varying fractures during the 475 N loading condition. Overall, a significantly lower survival for 14 mm crowns was found compared to 6 mm and 10 mm crowns (p = 0.004). Crown heights of one-piece screw-retained titanium implant crowns did not significantly affect detorque values. Screw fracture, however, was greater for crown height of 14 mm than those of 6 mm and 10 mm.

Fracture Resistance of Zirconia, Polyetheretherketone, and Polyetherketoneketone Implant Abutments After Aging.

This study aimed to assess the fracture resistance of zirconia (Zr), reinforced polyetheretherketone (PEEK), and polyetherketoneketone (PEKK) implant abutments restored with glass-ceramic crowns after thermomechanical aging. Zr, reinforced PEEK, and PEKK titanium base abutments were divided into three groups (n = 10). CAD/CAM maxillary central incisor crowns were fabricated using monolithic lithium disilicate and luted to the abutments using resin cement. The specimens were thermomechanically aged (1.2 × 106 cycles, 49 N, 5°C to 55°C). After testing fracture strength and determining fracture patterns, statistical analyses were made using the one-way analysis of variance (ANOVA) and Tukey post hoc tests (α = .05). Fracture resistance of the PEKK abutments (541.90 ± 68.49 N) was significantly lower than the Zr (780.65 ± 105.77 N) and reinforced PEEK (741.09 ± 99.84 N) abutments (P = .000). A significant discrepancy was not detected between the reinforced PEEK and Zr abutments. Failures usually formed due to crown or abutment fracture, plastic deformation of the titanium base or screw fracture in the Zr group, crown fracture or separation of the abutment-crown complex from the titanium base in the reinforced PEEK group, and abutment fracture without crown deformation in the PEKK group. After thermomechanical aging, the reinforced PEEK abutments exhibited similar fracture resistance to the Zr abutments. All abutment types withstood the physiologic occlusal forces typical for the oral anterior region. Before considering them as alternative esthetic implant abutment materials, further in vitro and clinical studies are needed to determine their long-term performance.

Removal of cement-augmented screws in distal femoral fractures and the effect of retained screws and cement on total knee arthroplasty: a biomechanical investigation

BackgroundGiven the increasing number of osteoporotic fractures of the distal femur, screw augmentation with bone cement is an option to enhance implant anchorage. However, in implant removal or revision surgeries, the cement cannot be removed from the distal femur without an extended surgical procedure. Therefore, the aims of this study were to investigate (1) whether cement augmentation has any influence on screw removal and removal torque, and (2) whether the implantation of a femoral component of a knee arthroplasty and its initial interface stability are affected by the remaining screws/cement.Material and methodsEight pairs of fresh-frozen human female cadaveric distal femurs (mean age, 86 years) with a simulated AO/OTA 33 A3 fracture were randomized in paired fashion to two groups and fixed with a distal femoral locking plate using cannulated perforated locking screws. Screw augmentation with bone cement was performed in one of the groups, while the other group received no screw augmentation. Following biomechanical testing until failure (results published separately), the screws were removed and the removal torque was measured. A femoral component of a knee arthroplasty was then implanted, and pull-out tests were performed after cement curing. Interference from broken screws/cement was assessed, and the maximum pull-out force was measured.ResultsThe mean screw removal torque was not significantly different between the augmented (4.9 Nm, SD 0.9) and nonaugmented (4.6 Nm, SD 1.3, p = 0.65) screw groups. However, there were significantly more broken screws in in the augmented screw group (17 versus 9; p < 0.001). There was no significant difference in the pull-out force of the femoral component between the augmented (2625 N, SD 603) and nonaugmented (2653 N, SD 542, p = 0.94) screw groups.ConclusionThe screw removal torque during implant removal surgery does not significantly differ between augmented and nonaugmented screws. In the augmented screw group, significantly more screws failed. To overcome this, the use of solid screws in holes B, C, and G can be considered. Additionally, it is possible to implant a femoral component for knee arthroplasty that retains the initial anchorage and does not suffer from interference with broken screws and/or residual cement.Level of Evidence 5

Cephalomedullary helical blade is independently associated with less collapse in intertrochanteric femur fractures than lag screws.

Excessive fracture site collapse and shortening in intertrochanteric femur fractures alter hip biomechanics and patient outcomes. The purpose of the study was to compare extent of collapse in cephalomedullary nails with blades or lag screws. We hypothesized that there would be no difference in collapse between helical blades and lag screws. Retrospective cohort study. Single U.S. Level I Trauma Center. 171 consecutive patients treated with cephalomedullary nails with either lag screw or blade for AO/OTA 31A1-3 proximal femur fractures and minimum 3-month follow-up. Lag screw or helical blade in a cephalomedullary nail. The primary outcome was fracture site collapse at 3months. There was a significantly higher proportion of reverse-oblique and transverse intertrochanteric femur fractures (31-A3) in the lag screw group (15/42 vs 25/129). A3 patterns were associated with more collapse. There was significantly less collapse in the blade group (median 4.7mm, inter-quartile range 2.5-7.8mm) than the screw group (median 8.4 mmm, inter-quartile range 3.7-11.2mm, p 0.006). Median collapse was no different between blades and screws when comparing stable and unstable patterns. However, blades were independently associated with 2.5mm less collapse (95%CI -4.2, -0.72mm, p 0.006) and lower likelihood of excessive collapse (> 10mm at 3months, OR 0.3, 95% CI 0.13-0.74, p 0.007), regardless of fracture pattern. Helical blades are independently associated with significantly less collapse than lag screws in intertrochanteric proximal femur fractures, after adjusting for unstable fracture patterns. In fracture patterns at risk for collapse, surgeons can consider use of a helical blade due to its favorable sliding properties compared to screws.

Partial Threading of Pedicle Screws in a Standard Construct Increases Fatigue Life: A Biomechanical Analysis

This study proposed a pedicle screw design where the proximal 1/3 of the screw is unthreaded to improve fixation in posterior spinal surgery. This design was also expected to reduce the incidence of mechanical failure often observed when an unsupported screw length is exposed outside the vertebra in deformed or degenerated segments. The aim of this study was to evaluate the fatigue life of the novel pedicle screw design using finite element analysis and mechanical testing in a synthetic spinal construct in accordance with American Society for Testing and Materials (ASTM) F1717. The following setups were evaluated: (i) pedicle screw fully inserted into the test block (EXP-FT-01 and EXP-PU-01; full thread (FT), proximal unthread (PU)) and (ii) pedicle screw inserted but leaving an exposed shaft length of 7.6 mm (EXP-FT-02 and EXP-PU-02). Corresponding finite element models FEM-FT-01, FEM-FT-02, FEM-PU-01, and FEM-PU-02 were also constructed and subjected to the same loading conditions as the experimental groups. The results showed that under a 220 N axial load, the EXP-PU-01 group survived the full 5 million cycles, the EXP-PU-02 group failed at 4.4 million cycles on average, and both EXP-FT-01 and EXP-FT-02 groups failed after less than 1.0 million cycles on average, while the fatigue strength of the EXP-FT-02 group was the lowest at 170 N. The EXP-FT-01 and EXP-FT-02 constructs failed through fracture of the pedicle screw, but a rod fractured in the EXP-PU-02 group. In comparison to the FEM-FT-01 model, the maximum von Mises stress on the pedicle screw in the FEM-PU-01 and FEM-PU-02 models decreased by −43% and −27%, respectively. In conclusion, this study showed that having the proximal 1/3 of the pedicle screw unthreaded can reduce the risk of screw fatigue failure when used in deformed or degenerated segments.

Evaluation of the mode of failure of abutments supporting implant-supported fixed partial dentures via different retention techniques.

The objective was to in-vitro evaluate the mode of failure of abutments supporting fixed partial dentures (FPDs) via different retention techniques. Thirty-six implants with diameter and length of 4.5 and 13 mm, respectively, were used to prepare 18 samples of FPDs. Based on the variations on abutment's design, the FPDs were divided into three groups: Group A is cement-based retention; Group B is screw-based retention; and Group C is multiunit screw-based retention. Using a chewing simulator, cyclic loads of 1,250,000 load cycles with the load of 70N were applied on all samples to simulate 5 years of human functional chewing. The samples were loaded until failure using an electromechanical test machine. Sample-size estimation was done and fracture-load values were recorded as means and corresponding standard deviations; and group comparisons were done using one-way analysis of variance and Tukey's post hoc tests. A P value below 0.01 was nominated as an indicator of statistical significance. In total, 36 samples (12 implant-abutment connections per group) were assessed. Abutment bending was observed in 6 (50%), 6 (50%) and 6 (50%) samples in groups A, B and C, respectively. De-attachment of the FPD form the abutment occurred in 5 (41.7%) and 5 (41.7%) samples in groups A and C, respectively. Screw fracture and fracture of FPD at the connector side occurred in 1 (8.3%) and 1 (8.3%) sample in groups A and C, correspondingly. Failure of the FPD was more often encountered in groups A (100%) and C (100%), compared to group B (50%). All abutments underwent failures under cyclic loading with abutment bending being the most common failure mode. Cement- and multi-screw-supported abutments fail more often than screw-supported abutments.

Mechanical testing of four-unit implant-supported prostheses with extensive pink gingiva porcelain: The dentogingival prostheses proof of concept.

To investigate the probability of survival and failure modes of four-unit implant-supported porcelain fused to metal (PFM) dentogingival prostheses subjected to step-stress accelerated life testing (SSALT). Eighteen implant-supported PFM dentogingival prostheses with thin metallic infrastructures, which provided minimal ceramic support and improved esthetics were fabricated over external hexagonal connection UCLA abutments. SSALT was performed until specimen failure. Use level probability Weibull curve and reliability were calculated and plotted. Weibull modulus (m) and characteristic strength (η) were also calculated. Polarized light microscope and scanning electron microscope were used to characterize fractures. Failures were dictated by material strength rather than fatigue damage accumulation. The probability of survival for loads reaching 100 and 150 N in 100,000 cycles was 92 and 61%, respectively. No cracks or fractures were identified in the veneered porcelain, whereas abutment fixation screw fracture was the chief failure mode. Implant-supported PFM four-unit dentogingival prostheses with minimum metal framework dimensions presented favorable lifetime prediction under fatigue testing. Fractures were restricted to fixation screws. In-vitro fatigue testing and failure mode analyses evidenced favorable lifetime prediction for 4-unit implant-supported dentogingival prostheses with minimum metal frameworks. Abutment fixation screw fracture might be the most frequent clinical complication. Since this proof of concept has been tested in-vitro, further studies including different restorative materials, as well as long-term clinical trials are warranted.

Management of perishing implants with abutment screw fracture - A systematic review.

Aim:To systematically review the reported techniques, for evaluating the risk and difficulty encountered in the management of fractured abutment screw in accordance with the location of fracture, and to develop a logical sequence in managing an implant abutment screw fracture.Settings and Design:Systematic review following PRISMA guidelines.Materials and Methods:A systematic search of the PubMed/MEDLINE database for articles published between January 2000 and March 2020 was performed by 2 independent reviewers. Case reports and case series that described the management of fractured implant abutment screw were included. Published articles were qualitatively analyzed employing CARE guidelines and were classified according to the location of screw fracture with respect to implant platform, risk of damage to the implant, and intervention for managing the fractured screw.Statistical Analysis Used:Qualitative analyisis.Results:A total of 28 articles were included in the review. Two of them explained the management of screw fracture at or above the implant platform and required only mild approach with low risk while the others explained the management of screw fracture below the level of implant platform. Among them, 6 were considered mild approach with low risk, 13 moderate approach with moderate risk, and 8 of them severe approach with high risk.Conclusion:Irrespective of the technique, any attempt to retrieve abutment screw fragment poses some risk to the implant which is varying from mild to severe. As the location of fracture is more gingival to the implant platform, difficulty of retrieval as well as risk to the implant increases. The proposed decisionmaking tree will be a useful tool in helping clinicians to manage abutment screw fracture.

Durability and Failure Types of S2-Alar-Iliac Screws: An Analysis of 312 Consecutive Screws

S2-alar-iliac (S2AI) screws improve stability across the lumbosacral junction in spinopelvic fixation procedures by crossing the cortical surfaces of the sacroiliac joint (SIJ), thereby increasing the biomechanical strength of the instrumentation. To investigate the durability and failure types of S2AI screws after spinopelvic reconstruction surgery. A single-center, single-surgeon consecutive series of patients who underwent spinopelvic fixation using bilateral S2AI screws with a≥1-yr follow-up and at least 1 postoperative computed tomographic scan were retrospectively reviewed. Patient characteristics, radiographic parameters, operative data, clinical outcomes, and complications were analyzed. In total, 312 S2AI screws in 156 patients were evaluated (mean follow-up, 26.1 mo; range 12-71 mo). There were no significant differences in screw diameter, length, or insertion angle between right-side and left-side screws. Visual analogue scale scores for back pain, ambulatory status, and Oswestry Disability Index scores significantly improved. A total of 10 patients (3.2%) experienced SIJ pain after S2AI screw installation. SIJ pain improved in 8 of them following SIJ block. In total, 7 screws (2.2%) showed partial periscrew lucency. Set screw dislodgement occurred in 7 screws (2.2%). Screw fracture occurred in 6 screws (1.9%): 5 neck fractures and 1 shaft fracture. A total of 5 patients (1.6%) underwent revision surgery for S2AI screw failure. Distal device (L4-pelvis region) breakage occurred in 5 patients. The radiographic and clinical outcomes of S2AI screw fixation were acceptable. However, S2AI screw fixation has several drawbacks, including screw fracture and dislodgement of the set screw. SIJ irritation symptoms after S2AI screw fixation occurred with considerable frequency.

Analysis of factors affecting the sliding length of the lag screws in trochanteric fractures

Analysis of factors affecting the sliding length of the lag screws in trochanteric fractures

Biological and prosthetic complications of cantilevered and non-cantilevered fixed hybrid metal acrylic prostheses used for vertical and inclined implants in atrophied mandible. A randomized clinical trial.

Aim: This study aimed to evaluate biological and prosthetic complications of cantilevered and non-cantilevered fixed hybrid metal acrylic prostheses used for vertical and inclined implants in atrophied mandible. Materials and Methods: Eight completely edentulous individuals will be classified into 2 groups randomly: 1) Group I (cantilevered prosthesis, n=4): patients received 4 vertical implants parallel to each other’s in the interforaminal area and cantilevered metal acrylic prosthesis, 2) Group II (non-cantilevered prosthesis, n=4): patients received 4 implants (2 parallel anterior implants and 2 posterior implants inclined 30odistally) and non-cantilevered metal acrylic prosthesis. Biological and prosthetic complications were measured after one year from prosthesis insertion. Results: There was no significant difference in implant failure, implant survival, pain, swelling, abscess, fistula formation, peri-implantitis, peri-implant mucositis, bleeding on probing between groups. The non-cantilevered group showed significantly higher pocket depth than the cantilevered group. The cantilevered group showed significantly higher bone loss than the non-cantilevered group. There were no prosthesis fractures, cylinder fracture, abutment fracture, and prosthetic screw fracture occurred in both groups. There was no difference in teeth wear, teeth fracture, and gingival fracture between groups. The cantilevered group showed a significantly higher crown fracture, abutment screw, and prosthetic loosening than the non-cantilevered group. Conclusion: Both cantilevered and non-cantilevered fixed hybrid metal acrylic prostheses can be used successfully for vertical and inclined implants respectively in atrophied mandible with favorable biologic and prosthetic outcomes after one year.

Результаты применения промежуточных транспедикулярных винтов при повреждениях переходного грудопоясничного отдела позвоночника

Background Short-segment transpedicular screw fixation (SSTSF) is the preferred treatment option for thoracolumbar burst fractures. Adding screws in the fractured body may be helpful in achieving and maintaining fracture reduction. However, the operative approach is disputed. Objective To compare clinical outcomes of transpedicular fixation with and without screws in the fractured vertebral body after isolated uncomplicated fractures at the thoracolumbar junction. Material and methods A retrospective cohort study enrolled 62 patients with Th11–L2 thoracolumbar burst fractures (AOSpine A3, A4) who underwent SSTSF with (n = 32) and without (n = 30) pedicle screws at the fracture level. Demographic data of the patients, operating time and blood loss were registered. Clinical evaluation using Visual analogue scale (VAS ) for pain, Oswestry Disability Index (ODI) to quantify disability and imaging parameters of segmental kyphosis, loss of correction, anterior vertebral body height (AVBH) at the fracture level, spinal canal stenosis (SCS) were measured preoperatively, at one week, 1 month, 6 and 12 months postoperatively. Results The patients of the two groups showed no statistically significant differences in the demographic data, VAS and ODI scores, measurements of kyphotic angle, AVBH, SCS preoperatively (p &gt; 0.05). Screws at the fracture level did not affect the operating time and intraoperative blood loss relative to conventional no-screw group. Benefits with fracture screws were evident at 7 days (p &lt; 0.01) measuring SCS, at 6 months (p &lt; 0.01) and 12 (p &lt; 0.01) months measuring kyphotic angle. There was better kyphosis correction (p &lt; 0.01) and AVBH (p = 0.034) seen at 12 months after surgery. Conclusion Reinforcement of a broken vertebra with fracture-level screws has been shown to provide better stability of clinical and radiographic results as compared to those with conventional SSTSF.

Biomechanical assessment of screw safety between far cortical locking and locked plating constructs

With the emerging concerns for more flexible and less stiff bridge constructs in the interest of stimulating bone healing, the technique of far cortical locking has been designed to reduce the stiffness of locked plating (LP) constructs while retaining construct strength. This study utilized simulation with diaphyseal bridge plating biomechanical models to investigate whether far cortical locking causes larger screw fracture risk than LP during rehabilitation. The fracture risk of the screws in the far cortical locking constructs increases in the non-osteoporotic and osteoporotic diaphysis compared with the screws in the LP constructs.