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PloS One 2022The aim of this study was to describe and evaluate a novel plate designed specifically for the canine ilium using finite element methods. The cranial portion of the...
INTRODUCTION
The aim of this study was to describe and evaluate a novel plate designed specifically for the canine ilium using finite element methods. The cranial portion of the plate had an elliptical shape and contained nine screw holes. The caudal portion of the plate was triangular with three screw holes. Four and three screws were used at the cranial (screw 1 to 4) and caudal (screw 5 to 7) segment of the plate. Finite element models of the plate and canine pelvis were created. A load of 300 N was applied on the femur-hip joint contact area. Values of Von Mises Stress on the plate, screws and the maximum and minimum main stresses in the bone were used to capture the mechanical factors in this study.
RESULTS
The novel implant had a plate stress of 51.9 megapascals (MPa) with higher stress in the dorsal part of the plate. Screws 2 and 4 showed similar stress values of 17.3 MPa. Screws 1 and 3 were the most loaded (51.9 MPa and 75 MPa, respectively). Screws 5, 6, and 7 showed similar dissipation and stress values (21.55 MPa). There was traction force in the dorsal region of the pubis and compression in the ventral part, with dissipation and values of 15.4 MPa and 23.9 MPa, respectively, acquiring balance between them.
CONCLUSION
The novel plate is potentially applicable and specifically suitable for iliac fractures in dogs. The screws distribution modeled proved itself strategical since the simulated stresses were evenly distributed throughout the implant construct.
Topics: Animals; Biomechanical Phenomena; Bone Plates; Bone Screws; Dogs; Finite Element Analysis; Fracture Fixation, Internal; Spinal Fractures; Stress, Mechanical
PubMed: 36018880
DOI: 10.1371/journal.pone.0269313 -
Journal of Orthopaedic Surgery and... Jan 2019This study aimed to explore the effect of retaining inferomedial cortical bone contact and fixation with calcar screws on the dynamic and static mechanical stability of...
BACKGROUND
This study aimed to explore the effect of retaining inferomedial cortical bone contact and fixation with calcar screws on the dynamic and static mechanical stability of proximal humerus fractures treated with a locking plate.
METHODS
Twelve Synbone prosthetic humeri (SYNBONE-AG, Switzerland) were used for a wedge osteotomy model at the proximal humerus, in four groups. In the cortex contact + screw fixation group and cortex contact group, the inferomedial cortical bone contact was retained. In the screw fixation group and control group, the inferomedial cortical bone contact was not retained. Calcar screw fixation was implemented only in the screw fixation groups. The dynamic and static mechanical stability of the models were tested with dynamic fatigue mechanics testing, quasi-static axial compression, three-point bending, and torsion testing.
RESULTS
The cortex contact + screw fixation group showed the longest fatigue life and the best stability. There was 35% difference in fatigue life between the cortex contact + screw fixation group and the cortex contact group, 43%between the cortex contact + screw fixation group and screw fixation group, and 63% between the cortex contact + screw fixation group and screw fixation group (P < 0.01). The cortex contact + screw fixation group showed the best axial compressive stiffness, bending stiffness, and torsion stiffness; these were successively decreased in the other three groups (P < 0.01).
CONCLUSION
Retaining inferomedial cortical bone contact and fixation with two calcar screws maintained fracture stability with the highest strength and minimum deformation. Of the two methods, restoration of the inferomedial cortical bone support showed better dynamic and static biomechanical properties than placement of calcar screws alone.
Topics: Bone Screws; Compressive Strength; Cortical Bone; Humans; Materials Testing; Random Allocation; Shoulder Fractures
PubMed: 30606215
DOI: 10.1186/s13018-018-1031-7 -
Internal Medicine (Tokyo, Japan) 2012
Topics: Bone Screws; Female; Hip Prosthesis; Humans; Metals; Middle Aged; Prosthesis Failure; Tomography, X-Ray Computed
PubMed: 22864144
DOI: 10.2169/internalmedicine.51.8111 -
Journal of Orthopaedic Research :... Dec 2022High failure rates have been associated with nonlocking cancellous screws with a typical buttress thread in patients with osteoporotic bone. This study aimed to develop...
High failure rates have been associated with nonlocking cancellous screws with a typical buttress thread in patients with osteoporotic bone. This study aimed to develop a novel thread design and compare its fixation stability with that of a typical buttress thread. Nonlocking cancellous screws with a novel thread design (proximal flank angle of 120 degrees, a flat crest feature, a tip-facing undercut feature) and nonlocking cancellous screws with a typical buttress thread were manufactured using stainless steel. Fixation stabilities were evaluated individually by the axial pullout and lateral migration tests, and they were evaluated in pairs together with a dynamic compression plate in an osteoporotic bone substitute (10 PCF polyurethane foam per ASTM F1839) under cyclic craniocaudal and torsional loadings. Pullout strength and lateral migration resistance for the individual screw test and the force, torque, and number of cycles required to achieve specific displacement and torsion for the multi-screw test were comparatively analyzed between both screw types. A finite element analysis model was constructed to analyze the stress distributions in the bone tissue adjacent to the threads. The biomechanical test revealed the novel undercut thread had superior axial pullout strength, lateral migration resistance, and superior fixation stability when applied to a dynamic compression plate under cyclic craniocaudal loading and torsional loading than those in the typical buttress thread. The finite element analysis simulation revealed that the novel thread can distribute stress more evenly without high-stress concentration at the adjacent bone tissue when compared to that of a typical buttress thread.
Topics: Humans; Bone Screws; Bone Plates; Torque; Mechanical Phenomena; Osteoporosis; Biomechanical Phenomena
PubMed: 35267202
DOI: 10.1002/jor.25305 -
Joint Diseases and Related Surgery May 2023In this review, we discuss the efficacy and safety of biodegradable magnesium screws compared to titanium screws in the treatment of hallux valgus (HV) in patients... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
In this review, we discuss the efficacy and safety of biodegradable magnesium screws compared to titanium screws in the treatment of hallux valgus (HV) in patients undergoing distal metatarsal osteotomy (DMO).
MATERIALS AND METHODS
Eligible scientific articles published prior to October 2022 were retrieved from the PubMed, Springer, ScienceDirect, and Cochrane Library databases. The terms used for searching included "hallux valgus", "distal metatarsal osteotomies", and "bioabsorbable magnesium screw" which were limited in the title or abstract through the text. The title and abstract were checked one by one to exclude the non-related studies. For primary identified studies and relevant systematic reviews, the full texts were accessed and browsed to finally include the eligible studies. No restriction was set on publication language and publication status.
RESULTS
Two randomized-controlled trials (RCTs) and three non-RCTs that met the inclusion criteria were included. There was no significant difference in the American Orthopaedic Foot and Ankle Society (AOFAS) score, postoperative HV angle (HVA), intermetatarsal angle (IMA), Visual Analog Scale (VAS) score, soft tissue irritation, implant fracture, reoperation, and infection rates between two groups.
CONCLUSION
Bioabsorbable magnesium compression screws show comparable clinical or radiological results to titanium compression screws in the treatment of HV in patients undergoing DMO.
Topics: Humans; Titanium; Magnesium; Treatment Outcome; Metatarsal Bones; Absorbable Implants; Hallux; Hallux Valgus; Osteotomy; Bone Screws
PubMed: 37462631
DOI: 10.52312/jdrs.2023.1026 -
Neurology India Dec 2005
Review
Topics: Biomechanical Phenomena; Bone Screws; Fracture Fixation; Humans; Orthopedic Procedures; Pelvis; Spinal Fusion; Spine
PubMed: 16565541
DOI: 10.4103/0028-3886.22618 -
European Spine Journal : Official... 1999
Topics: Bone Screws; Humans; Scoliosis; Spinal Cord Compression
PubMed: 15617222
DOI: 10.1007/s005860050148 -
Orthopaedics & Traumatology, Surgery &... Oct 2022Correcting pelvic obliquity is among the main goals of surgery for neuromuscular scoliosis. Spino-pelvic fixation must be stable and capable of withstanding the...
BACKGROUND
Correcting pelvic obliquity is among the main goals of surgery for neuromuscular scoliosis. Spino-pelvic fixation must be stable and capable of withstanding the considerable mechanical forces applied at the lumbo-sacral junction. Selection of the best anchoring option is therefore crucial. S2-alar-iliac (S2AI) screws, which are used in adults, are less often chosen in the French paediatric spinal-surgery community. The objective of this study was to report our preliminary experience with S2AI screws used in the treatment of paediatric patients with neuromuscular scoliosis.
HYPOTHESIS
Pelvic anchoring by means of S2AI screws is reliable and technically feasible in non-ambulatory children with neuromuscular scoliosis.
MATERIALS AND METHODS
Consecutive non-ambulatory patients who underwent scoliosis surgery with S2AI screw fixation to the pelvis between 2016 and 2018 were retrospectively included. The surgical procedure consisted in either posterior spinal fusion (PSF) or magnetic growing rod (MGR) implantation. In all patients, radiographs were obtained before surgery, within 3 months after surgery, and at last follow-up; and low-dose computed tomography (CT) was performed before and after surgery.
RESULTS
We included 25 patients with a mean age of 13.8±4.0 years, 18 managed by PSF and 7 by MGRs. Screw diameters ranged from 7.5 to 9.5mm and all screws were at least 60mm in length. The diameters and lengths were the same on both sides in 16 (89%) patients in the PSF group and in all patients in the MGR group. At last follow-up after a mean of 35.5±3.0 months, pelvic obliquity was corrected in all 23 patients with this abnormality before surgery. Complications consisted of lateral cortical screw breakthrough in 8 (32% of screws) patients and screw malposition in 2 (8% of screws) patients. No clinically significant complications related to the fixation material were recorded.
DISCUSSION
The results of our study demonstrate the feasibility of S2AI screw fixation in paediatric patients with neuromuscular scoliosis. Pelvic asymmetry and dysmorphism do not contra-indicate the procedure but must be evaluated before surgery. Further work is needed to assess the potential long-term consequences on pain and growth of screw passage through the sacro-iliac joints.
LEVEL OF EVIDENCE
IV, retrospective study.
Topics: Adolescent; Adult; Bone Screws; Child; Humans; Ilium; Neuromuscular Diseases; Retrospective Studies; Sacrum; Scoliosis; Spinal Fusion
PubMed: 35144011
DOI: 10.1016/j.otsr.2022.103234 -
Veterinary Surgery : VS Jul 2022Determine compression generated by lag and neutral screws over 12 h using two bone analogs.
OBJECTIVE
Determine compression generated by lag and neutral screws over 12 h using two bone analogs.
STUDY DESIGN
Experimental study.
SAMPLE POPULATION
Bone analogs were made of composite synthetic bone (CSB) or three-dimensional printed polylactic acid (PLA). Analogs had a 2 mm exterior shell with a 10 mm thick internal layer of open-cell material.
METHODS
Bone analogs were opposed, making a 4-sided box with open ends. A central channel contained the sensor and the screws passed through it to engage both paired analogs. Four screw/analog conditions were tested: neutral and lag screw with bicortical engagement, neutral and lag screw with unicortical engagement. All screws were tightened to 2 Nm torque and compression values recorded at 0, 0.5, 1, 2, 6, and 12 h (six trials per condition). Medians were compared across groups for statistical significance.
RESULTS
There was no difference in median compression between lag and neutral bicortical screws. For PLA, greater median compression was generated by neutral (median 437 N) and lag (median 379 N) bicortical screws compared to neutral unicortical screws (median 208 N, p < .001); lag bicortical screws generated greater median compression than lag unicortical screws (median 265 N, p = .012). For CSB, lag bicortical screws (median 293 N) generated greater median compression than neutral unicortical screws (median 228 N, p = .008).
CONCLUSION
Lag and neutral screws generated similar compression. Bicortical screws had higher median compression than unicortical screws in bone analogs.
CLINICAL SIGNIFICANCE
Neutral screws generate compression in cancellous bone analogs that can be increased with bicortical bone engagement.
Topics: Animals; Biomechanical Phenomena; Bone Screws; Cysts; Fracture Fixation, Internal; Horse Diseases; Horses; Polyesters
PubMed: 35394080
DOI: 10.1111/vsu.13814 -
Journal of Orthopaedic Surgery and... Jun 2022Minimally invasive surgery for pelvic fracture using anterior ring internal fixator system is increasing gradually, and the way to insert the fixation screws in the...
BACKGROUND
Minimally invasive surgery for pelvic fracture using anterior ring internal fixator system is increasing gradually, and the way to insert the fixation screws in the fixation system is the key technical points of the method. However, there have been few studies on insertion of fixation screws for the anterior pelvic ring internal fixator system.
OBJECTIVE
To identify safe channels for fixation screws in the anterior pelvic fixator system and provide the anatomical basis for insertion of fixation screws in clinical operation.
METHODS
Screw insertion was simulated into a total of 40 pelvic finite element models as well as 16 fresh pelvic specimens, and the channel parameters were measured.
RESULTS
Finite elements (male, female) include: screws in ilium: length 114.4 ± 4.1 and 107.6 ± 8.3 mm, respectively; diameter 11.7 ± 0.5 and 10.0 ± 0.6 mm, distance between screw and anterior inferior iliac spine: 5.5 ± 1.0 and 5.6 ± 1.0 mm, angle of coronal plane 55.8° ± 2.4° and 50.6° ± 3.1°, angle of sagittal plane 26.6° ± 1.0° and 24.5° ± 1.9° and angle of horizontal plane 64.9 ± 3.7 and 58.1 ± 3.1; screws in pubis: length 47.0 ± 2.0 and 39.8 ± 3.9 mm, diameter 7.1 ± 0.4 and 6.1 ± 0.4 mm. Specimens (male, female) include: distance between screw and anterior inferior iliac spine: 5.5 ± 0.5 and 5.6 ± 0.7 mm, angle of coronal plane 55.9° ± 1.3° and 50.7° ± 1.5°, angle of sagittal plane 26.7° ± 0.5° and 24.1° ± 0.9° and angle of horizontal plane 64.8° ± 0.6° and 58.8° ± 0.8°. In the comparison between female and male in each group, differences in distances between screws and anterior inferior iliac spine and median line of symphysis pubis (P > 0.05) were not statistically significant; differences in the remaining parameters were statistically significant (P < 0.05).
CONCLUSIONS
If surgeons paid attention to sex differences, select screws of appropriate diameter and length and hold the insertion position and direction, screws in the anterior pelvic ring fixation system could be safely inserted.
Topics: Bone Screws; Female; Fracture Fixation, Internal; Fractures, Bone; Humans; Ilium; Male; Pelvic Bones; Pelvis
PubMed: 35690864
DOI: 10.1186/s13018-022-03191-5