Bone quality affects stability of orthodontic miniscrews.

The objective of this study was to evaluate the effect of bone-miniscrew contact percentage (BMC%) and bone quality and quantity on orthodontic miniscrew stability and the maximum insertion torque value (ITV). Orthodontic miniscrews of five different dimensions and several bovine iliac bone specimens were used in the evaluation. Miniscrews of each dimension group were inserted into 20 positions in bovine iliac bone specimens. The experiment was divided into three parts: (1) Bone quality and quantity were evaluated using cone-beam computed tomography (CBCT) and microcomputed tomography. (2) The 3D BMC% was calculated. (3) The ITVs during miniscrew insertion were recorded to evaluate the stability of the orthodontic miniscrews. The results indicated that longer and thicker miniscrews enabled higher ITVs. CBCT was used to accurately measure cortical bone thickness (r = 0.939, P < 0.05) and to predict the bone volume fraction of cancellous bone (r = 0.752, P < 0.05). BMC% was significantly influenced by miniscrew length. The contribution of cortical bone thickness to the ITV is greater than that of cancellous bone structure, and the contribution of cortical bone thickness to BMC% is greater than that of cancellous bone structure. Finally, the higher is BMC%, the greater is the ITV. This study concludes that use of CBCT may predict the mechanical stability of orthodontic miniscrews.

Comparison of the fixation ability of headless compression screws and locking plate for metacarpal shaft transverse fracture.

ABSTRACT: Metacarpal shaft fractures are common hand fractures. Although bone plates possess strong fixation ability, they have several limitations. The use of headless compression screws for fracture repair has been reported, but their fixation ability has not been understood clearly.This study aimed to compare the fixation ability of locked plate with that of headless compression screw for metacarpal fracture repair.A total of 14 artificial metacarpal bones (Sawbones, Vashon, WA, USA) were subjected to transverse metacarpal shaft fractures and divided into 2 groups. The first group of bones was fixed using locked plates (LP group), whereas the second group was fixed using headless compression screws (HC group). A material testing machine was used to perform cantilever bending tests, whereby maximum fracture force and stiffness were measured. The fixation methods were compared by conducting a Mann-Whitney U test.The maximum fracture force of the HC group (285.6 ±â€Š57.3 N, median + interquartile range) was significantly higher than that of the LP group (227.8 ±â€Š37.5 N; P < .05). The median of the HC group was 25.4% greater. However, no significant difference in stiffness (P > .05) was observed between the HC (65.2 ±â€Š24.6 N/mm) and LP (61.7 ±â€Š19.7 N/mm) groups.Headless compression screws exhibited greater fixability than did locked plates, particularly in its resistance to maximum fracture force.

Lateral migration resistance of screw is essential in evaluating bone screw stability of plate fixation.

Conventional evaluation of the stability of bone screws focuses on pullout strength, while neglecting lateral migration resistance. We measured pullout strength and lateral migration resistance of bone screws and determined how these characteristics relate to screw stability of locking plate (LP) and dynamic compression plate (DCP) fixation. Pullout strength and lateral migration resistance of individual bone screws with buttress, square, and triangular thread designs were evaluated in polyurethane foam blocks. The screw types with superior performance in each of these characteristics were selected. LP and DCP fixations were constructed using the selected screws and tested under cyclic craniocaudal and torsional loadings. Subsequently, the association between individual screws' biomechanical characteristics and fixation stability when applied to plates was established. Screws with triangular threads had superior pullout strength, while screws with square threads demonstrated the highest lateral migration resistance; they were selected for LP and DCP fixations. LPs with square-threaded screws required a larger force and more cycles to trigger the same amount of displacement under both craniocaudal and torsional loadings. Screws with triangular and square threads showed no difference in DCP fixation stability under craniocaudal loading. However, under torsional loading, DCP fixation with triangular-threaded screws demonstrated superior fixation stability. Lateral migration resistance is the primary contributor to locking screw fixation stability when applied to an LP in resisting both craniocaudal and torsional loading. For compression screws applied to a DCP, lateral migration resistance and pullout strength work together to resist craniocaudal loading, while pullout strength is the primary contributor to the ability to resist torsional loading.

Comparison of the Efficiency of Two Novel Guided Bone Regeneration Devices in the Rabbit Calvarial Model.

BACKGROUND: Creating a secluded large space using guided bone regeneration (GBR) is a novel osteogenesis technique used in the prevention of premature membrane exposure complications. However, this technique is not considered clinically feasible. OBJECTIVES: This study aimed to compare the outcome of the insertion of two novel GBR devices in a rabbit calvarial model in terms of mode of action, simplicity, and amount of new space and bone gained. MATERIALS AND METHODS: The expansible GBR (EGBR) device, composed mainly of a titanium plate, silicone membrane, and activation screw, was inserted beneath the periosteum in the calvarial area of eight rabbits. The smart GBR (SGBR) device, composed of silicone sheets and Nitinol strips, were inserted beneath the periosteum in the calvarial area of another 10 rabbits. Half of each group was sacrificed 2 months after surgery, and the other half was sacrificed after 4 months. RESULTS: Histological and microradiographical analysis showed that, at 2 months, the EGBR device achieved a mean space gain of 207.2 mm3, a mean bone volume of 68.2 mm3, and a mean maximum bone height of 1.9 mm. Values for the same parameters at 4 months were 202.1 mm3, 70.3 mm3, and 1.6 mm, respectively. The SGBR device had significantly higher (P < 0.05) mean space gain (238.2 mm3; 239.5 mm3), bone volume (112.9 mm3, 107.7 mm3), and bone height (2.7 mm; 2.6 mm) than the EGBR device at 2 and 4 months, respectively. CONCLUSION: Both devices proved to be effective in augmenting bone vertically through the application of GBR and soft tissue expansion processes. However, the SGBR device was more efficient in terms of mode of action, simplicity, and amount of bone created in the new space.

Fractured coracoid process with acromioclavicular joint dislocation: A case report.

RATIONALE: Coracoid processes (CPs) fracture with acromioclavicular (AC) joint dislocation are extremely rare. This combined injury has brought many challenges to surgeons, and the mechanism underlying the injury is still not fully understood. There is no clear consensus on its treatment. PATIENT CONCERNS: Here, we describe a CP fracture with AC joint dislocation in a middle-aged manual worker. DIAGNOSIS: Radiographs showed a fracture of the base of the CP and a third-degree AC joint separation. INTERVENTIONS: The patient was treated surgically with open reduction and internal fixation of the AC joint by LCP clavicle hook plate, and the CP was fixed with a 3.5 mm diameter cannulated screw. OUTCOMES: Three months after the operation, shoulder function was completely restored, and the affected shoulder had full mobility with no tenderness. Plain film radiography showed anatomical indications of the healing of these combined injuries. LESSONS: Although AC joint dislocation with CP fractures is extremely rare in adults, it is important to remind and remember that this possibility exists. In unclear cases, special radiographic films and CT are necessary. Surgical treatment of AC joint dislocation with CP fractures can provide solid stability and restore normal shoulder function with an excellent prognosis.

The implant density does not change the correction rate of the main and the accompanying curves: A comparison between consecutive and intermittent pedicle screw constructs.

OBJECTIVE: The aim of this study was to evaluate the clinical outcomes and the coronal correction rate of the main and accompanying curves of adolescent idiopathic scoliosis (AIS) corrected with pedicle screws inserted consecutively or intermittently. METHODS: The prospectively collected data of 60 patients (8 men and 52 women; mean age: 14.6±2.5 years) who underwent corrective surgery for AIS between January 2010 and December 2015 were reviewed retrospectively. Two groups were constituted according to the pedicle screw construct type: consecutive pedicle screw construct (CPSC) and intermittent pedicle screw construct (IPSC) groups. The preoperative, early postoperative, and 24-month follow-up radiographs and the Scoliosis Research Society-22 (SRS-22) scores were reevaluated. The Cobb angle of the main and accompanying curves, the correction rate, and the flexibility of the curves were calculated. RESULTS: The mean preoperative Cobb angles were 57.03° and 57.46°, the mean postoperative Cobb angles were 14.93° and 14.4°, and the mean correction rates were 76.22% and 75.31% in IPSC and CPSC groups, respectively (p>0.05). The preoperative and postoperative accompanying curve magnitudes and correction rates were similar (p>0.05). These radiographic outcomes were also consistent with the SRS-22 scores. CONCLUSION: Both the pedicle screw constructs had satisfactory outcomes following the surgery, which were confirmed by both the SRS-22 scores and radiographs taken perioperatively and at follow-ups. The IPSC and CPSC groups did not demonstrate a significant change in the correction rate of the main and minor or major accompanying structural and nonstructural curves, and also in the SRS-22 scores. LEVEL OF EVIDENCE: Level III, Retrospective comparative study.

Comparison of dynamic hip screw and antirotation screw with cannulated screw in the treatment of transcervical collum femoris fractures.

OBJECTIVES: This study aims to compare the results of internal fixation with dynamic hip screw (DHS)/antirotation screw and conventional cannulated screw (CS) for femoral neck fracture. PATIENTS AND METHODS: This retrospective study included a total of 78 patients (57 males, 21 females) with collum femoris fractures treated with internal fixation between January 2015 and January 2019. Group 1 comprised 41 patients with a mean age of 45.7 years (range, 19 to 62 years) treated with DHSs/antirotation screws, while group 2 comprised 37 patients with a mean age of 41.9 years (range, 17 to 75 years) treated with CSs. The patients were evaluated for union, avascular necrosis (AVN), femoral neck shortness, operation time, duration of fluoroscopy exposure, and functional outcomes. RESULTS: Age, gender, and Garden classification stages were similar in both groups. No significant difference was found between the groups in respect of AVN and non-union rates. The non-union rate was 12.2% in group 1 and 21.6% in group 2 (p>0.05). The duration of fluoroscopy exposure was statistically significantly higher in group 2 (p=0.001) and the operation time was statistically significantly longer in group 1 (p=0.001). In group 2, femoral neck shortness stature was significantly higher (p=0.007). At the final follow-up examination, the Harris hip score was statistically significantly higher in group 1 (p=0.04). CONCLUSION: Dynamic hip screw/antirotation screw was a more relevant treatment method for transcervical femoral neck fractures compared to CS with more favorable functional outcomes and less fluoroscopy exposure.

Three-Dimensional Printed Porous Titanium Screw with Bioactive Surface Modification for Bone-Tendon Healing: A Rabbit Animal Model.

The interference screw fixation method is used to secure a graft in the tibial tunnel during anterior cruciate ligament reconstruction surgery. However, several complications have been reported, such as biodegradable screw breakage, inflammatory or foreign body reaction, tunnel enlargement, and delayed graft healing. Using additive manufacturing (AM) technology, we developed a titanium alloy (Ti6Al4V) interference screw with chemically calcium phosphate surface modification technology to improve bone integration in the tibial tunnel. After chemical and heat treatment, the titanium screw formed a dense apatite layer on the metal surface in simulated body fluid. Twenty-seven New Zealand white rabbits were randomly divided into control and additive manufactured (AMD) screw groups. The long digital extensor tendon was detached and translated into a tibial plateau tunnel (diameter: 2.0 mm) and transfixed with an interference screw while the paw was in dorsiflexion. Biomechanical analyses, histological analyses, and an imaging study were performed at 1, 3, and 6 months. The biomechanical test showed that the ultimate pull-out load failure was significantly higher in the AMD screw group in all tested periods. Micro-computed tomography analyses revealed early woven bone formation in the AMD screw group at 1 and 3 months. In conclusion, AMD screws with bioactive surface modification improved bone ingrowth and enhanced biomechanical performance in a rabbit model.

3-Dimensional printing templates guiding versus free hand technique for cervical lateral mass screw fixation: A prospective study.

OBJECTIVE: In this randomized, single blind and controlled study, the feasibility and precision of 3-dimensional printing templates for cervical lateral mass screw insertion was evaluated. METHODS: A total of 6 patients (72 screws), who were diagnosed with cervical spondylotic myelopathy (CSM) and developmental cervical spinal stenosis, were randomly divided into A and B two groups. All subjects underwent modified posterior surgery with using cervical lateral mass screws insertion (C4-C6). Group A underwent surgeries with screw insertion assisted by the guidance of 3-dimensional printing templates and Group B underwent surgeries with screw insertion by freehand. The criteria of the accuracy of screw placement were set as the main evaluation indicators. RESULTS: There was no significant difference between the 2 groups in age, improvement rate of JOA, operation time and blood loss. According to Bayard's criteria, 32 screws (88.9%) were described as "acceptable" in group A and 22 screws (61.1%) were described as "acceptable" in Group B (P < 0.05). Based on our criteria, the "excellent and good" rate of screws was 83.3% in group A and 47.2% in Group B, respectively (P < 0.05). The precision of screws' location in Group A was superior to that in Group B. CONCLUSIONS: 3-Dimensional printing screw insertion templates may achieve (1) comprehensive visualization of the cervical vertebrae and lateral mass and the individual surgical planning using the 3-dimensional model preoperatively. (2) increasing the accuracy of cervical lateral mass screw insertion.

Two-hole versus four-hole plate dynamic hip screw: a systematic review of current evidence.

BACKGROUND: The dynamic hip screw (DHS) is a common device used in the fixation of hip fractures. Traditionally, this involves the use of a four-hole side plate. Reducing the length of the side plate would theoretically reduce the amount of surgical exposure required, decrease surgery duration, and decrease perioperative morbidity and mortality. Our study aims to review the current evidence regarding the use of two-hole side plates, their use and potential complications. METHODS: Using PRISMA guidelines, two independent reviewers performed a search to collate the available literature from medical databases PubMed, EMBASE, Web of Science, and the Cochrane library. Only clinical and biochemical studies were included. The reference lists of articles included for full text review were searched for any additional primary or review publications. RESULTS: Four online libraries were searched, with a combined total of 5344 titles reviewed. Following title, abstract, and full text review, 8 articles were considered suitable for inclusion in qualitative analysis. There was a trend towards equal efficiency between two- and four-hole plates when used in stable fractures in terms of blood loss, failure/revision rates, operative and hospital stay durations, collapse loading testing, maximum stress, and fragment migration. CONCLUSION: The results of this study show that DHS constructs with two- or four-hole side plates have comparable outcomes when used in patients with stable fracture patterns. However, the majority of the clinical data regarding the use of two-hole DHS plates come from retrospective case series; further prospective, randomised control trials would be of significant benefit. LEVEL OF EVIDENCE: Level II; systematic review of all levels of evidence.

A distal start point facilitates safer insertion of S2-alar-iliac screws fixation.

This study aimed to show that a more distal insertion of S2-alar-iliac screws (S2AI) towards the S2 foramen facilitates a more natural trajectory and results in fewer breaches of the iliac wing due to the anteroposterior relationship of the sacrum and pelvis. Thirty-six consecutive patients who had received S2AI and postoperative computed tomography (CT) imaging were retrospectively reviewed. A freehand technique was used to insert all screws. Screws were stratified into two groups (Zone A and Zone B) based on the insertion point within the sacrum. Zone A was defined as screw insertion proximal to the second sacral foramen. Zone B was defined as screw insertion at or distal to the level of the second sacral foramen. CT imaging was reviewed to identify passage of the screw through either the fibrous or bony sacroiliac joint, and to check for instrumentation breach of the iliac wing. Sixty-two S2AI in 36 patients were identified. Twenty-six screws (42%) were inserted into Zone A and 36 (58%) into Zone B. There were 11 instrumentation breaches of the iliac wing in Zone A (42%) and 0 in Zone B (p < 0.0001). In Zone A, 24 screws (92%) passed through the upper, fibrous portion of the sacroiliac joint. In Zone B, no screws passed through this region (p < 0.0001). In conclusion, insertion of S2AI at or distal to the second sacral foramen facilitates improved screw placement due to the anteroposterior relationship of the sacrum and pelvis at this level.

Improved Accuracy of Cervical Spinal Surgery With Robot-Assisted Screw Insertion: A Prospective, Randomized, Controlled Study.

STUDY DESIGN: Prospective, randomized, controlled trial. OBJECTIVE: To compare robot-assisted and conventional implantation techniques by evaluating the accuracy and safety of implanting screws in cervical vertebrae. SUMMARY OF BACKGROUND DATA: Cervical spinal surgery is difficult and dangerous as screw misplacement might lead not only to decreased stability but also neurological, vascular, and visceral injuries. A new robot-assisted surgical procedure has been introduced to improve the accuracy of implant screw positioning. METHODS: We randomly assigned 135 patients with newly diagnosed cervical spinal disease and who required screw fixation using either robot-assisted or conventional fluoroscopy-assisted cervical spinal surgery. The primary outcomes were the discrepancies between the planned trajectories and the actual screw positions. RESULTS: Altogether, 127 patients underwent the assigned intervention (61 robot-assisted and 66 conventional fluoroscopy-assisted). The baseline characteristics including the screw types, were similar in the two groups. Altogether, 390 screws were planed and placed in the cervical vertebrae, and 94.9% were acceptable. The robot-assisted group had a better screw placement accuracy than the conventional fluoroscopy-assisted group with associated P values <0.001 (0.83 [0.44, 1.29] vs. 1.79 [1.41, 2.50] mm). The Gertzbein and Robbins scales also showed a significant difference between the two groups (P < 0.001). Furthermore, the robot-assisted group experienced significantly less blood loss during surgery than the conventional fluoroscopy-assisted group (200 [50, 375] vs. 350 [100, 500] mL; P = 0.002) and shorter length of stay after surgery (P = 0.021). These two groups did not differ significantly regarding the duration of the operation (P = 0.525). Neurological injury occurred in one case in the conventional fluoroscopy-assisted group. CONCLUSION: The accuracy and clinical outcomes of cervical spinal surgery using the robot-assisted technique tended to be superior to those with the conventional fluoroscopy-assisted technique in this prospective, randomized, controlled trial. LEVEL OF EVIDENCE: 2.

Is Initial Posterior Atlantoaxial Fixation and Fusion Applying Bilateral C1-2 Transarticular Screws and C1 Laminar Hooks Reliable for Acute Pediatric Atlantoaxial Instability?: A Minimal 10-Year Analysis of Outcome and Radiological Evaluation.

STUDY DESIGN: A retrospective case series study with at least 10 years of follow-up data. OBJECTIVE: To validate the reliability of bilateral C1-2 transarticular screws and C1 laminar hooks and a bone autograft for acute pediatric atlantoaxial instability. SUMMARY OF BACKGROUND DATA: The reliability of initial posterior atlantoaxial fusion in pediatric patients is still controversial. To date, however, only a few published articles with short-term follow-up data are available to help spinal surgeons understand the effects of posterior atlantoaxial fusion in the skeletally immature spine. METHODS: Five pediatric patients with acute atlantoaxial instability underwent atlantoaxial fusion using the above technique over a 3-year period. During a minimum 10-year follow-up period, not only outcomes and complications were investigated, but the vertical growth of the constructed spine in relation to the growth of the entire cervical spine, overall cervical spinal alignment, and adjacent-segment instability were evaluated. RESULTS: The clinical follow-up indicated solid fusion and complete clinical relief from symptoms. No neural or vascular impairment was observed. The radiological evaluation showed that all patients had growth within the fusion construct reaching a mean 35.4% of the entire cervical spine. There were no radiological indicators of subaxial instability, even when cervical sagittal alignments became straight with a mean C2-7 angle of 6.4°. CONCLUSION: The results showed that initial posterior atlantoaxial fusion accomplished with bilateral C1-2 transarticular screws, C1 laminar hooks fixation, and bony autograft is a reliable surgical technique for treating acute pediatric atlantoaxial instability without negative effects on vertical growth at the fused level or the stability of the subaxial spine. LEVEL OF EVIDENCE: 3.

Feasibility of iliosacral screw placement in patients with upper sacral dysplasia.

BACKGROUND: Exact knowledge of the sacral anatomy is crucial for the percutaneous insertion of iliosacral screws. However, dysplastic anatomical patterns are common. In addition to a preoperative computed tomography (CT) analysis, conventional radiographic measures may help to identify upper sacral dysplasia and to avoid damage to surrounding structures. Aiming to further increase safety in percutaneous iliosacral screw placement in the presence of sacral dysmorphism, this study examined the prevalence of previously established radiographic signs and, in addition, defined the "critical SI angle" as a new radiographic criterion. METHODS: Pelvic CT scans of 98 consecutive trauma patients were analysed. Next to assessment of established signs indicating upper sacral dysplasia, the critical sacroiliac (SI) angle was defined in standardized pelvic outlet views. RESULTS: The critical SI angle significantly correlates with the presence of mammillary bodies and an intraarticular vacuum phenomenon. With a cut-off value of - 14.2°, the critical SI angle detects the feasibility of a safe iliosacral screw insertion in pelvic outlet views with a sensitivity of 85.9% and a specificity of 85.7%. CONCLUSIONS: The critical SI angle can support the decision-making when planning iliosacral screw fixation. The clinical value of the established signs of upper sacral dysplasia remains uncertain.

Spine Growth Modulation in Early Adolescent Idiopathic Scoliosis: Prospective US FDA IDE Pilot Study of Titanium Clip-Screw Implant at Two to Five Years.

STUDY DESIGN: Prospective longitudinal study of growth modulation system for early adolescent idiopathic scoliosis (AIS), consecutive case series from first human use to skeletal maturity, fusion, or five years postoperation. OBJECTIVES: Determine adverse events and curvature changes to end of study; examine factors most likely to explain variability in curve changes. SUMMARY OF BACKGROUND: Pilot clinical safety study was performed under US Food and Drug Administration (FDA) Investigational Device Exemption (IDE). Safety and radiographic results were previously reported to 24 months postoperation. METHODS: Subjects with early AIS underwent thoracoscopic placement of titanium clip-screw devices designed to modify growth asymmetrically. Eligibility was based on high risk of progression to 50°: single major thoracic curve 25°-40°, Risser 0, open triradiate cartilages, and premenarchal if female. Six subjects, the maximum allowed, enrolled. Adverse events (AEs), clinical outcomes, and curvatures were systematically collected. Disc heights, vertebral heights, and implant-bone contact areas were assessed. RESULTS: Consecutive subjects enrolled, aged 12.1 years (±1.7), three were female. AEs from two to five years postoperation included deformity changes leading to a second surgery in three patients: two for posterior spinal fusion, and one for thoracoscopic removal of half the implants for overcorrection. In the latter case, overcorrection appeared halted for duration of study. One patient, whose curve exceeded 50° at age 18 years, did not choose fusion. Major thoracic curves were 34° (±3°) preoperatively and 42° (±20°) at end of study. CONCLUSIONS: In a study of spine growth modulation in patients with early AIS with high risk of progression, at skeletal maturity or five years postoperation, major thoracic curves of half progressed to >50°, whereas curves of the other half remained <40°, below fusion indications. Removal of selected implants may halt overcorrection. The next, pivotal, study phase was approved by FDA. LEVEL OF EVIDENCE: Level IV, prospective case series under stringent regulatory controls.

Surgical Fixation Using Screw-Rod Construct Instrumentation for Upper Cervical Instability in Pediatric Down Syndrome Patients.

STUDY DESIGN: Retrospective case series. OBJECTIVES: To describe the indications and outcomes of cervical fixation using modern instrumentation in a case series of pediatric Down syndrome (DS) patients. SUMMARY OF BACKGROUND DATA: Cervical instability is the major cervical spine concern in children with DS. Although fixation techniques have advanced over the past quarter-century, the outcome of fixation with modern instrumentation for upper cervical instability in DS patients has not been thoroughly investigated. METHODS: We searched the orthopedic database at our institution for patients with a diagnosis of DS who had undergone a cervical spine fusion between 2006 and 2017. Patient demographics, diagnoses, surgical indications, surgical details, and complications were recorded. Preoperative imaging was reviewed to determine atlanto-dens intervals and spinal cord signal changes. Postoperative radiographs or CT scans were reviewed to determine union. RESULTS: Twelve DS patients met our inclusion criteria. The mean age at surgery was 9.3 years (range 3.8-18.8 years). Patients with secondary causes of instability included 7 patients with os odontoideum and 1 patient with a pars fracture. Three patients (25%) were identified on asymptomatic screening, with none of these having cord signal changes on magnetic resonance imaging (MRI). Modern implants (screws, plates, cages) were used in every patient in our series. The mean number of levels fused was 1.9 (range 1-5). The overall complication rate was 41.7% (5/12). Four patients required repeat surgery for nonunion. All patients with adequate radiographic follow-up demonstrated union (11/11, 100%). One patient was lost to follow-up. CONCLUSIONS: Fixation for cervical instability is a critical component of the management of DS. A minority of patients receiving surgery were identified through asymptomatic screening. There was a high complication risk associated with surgery in our study; however, the addition of rigid fixation has lessened the complication rate compared with previous studies. LEVEL OF EVIDENCE: Level IV.

Safe zones of the maxillary alveolar bone in Down syndrome for orthodontic miniscrew placement assessed with cone-beam computed tomography.

The aim of this study was to quantify the available maxillary alveolar bone in a group of individuals with Down syndrome (DS) to determine the best areas for orthodontic miniscrew placement. The study group consisted of 40 patients with DS aged 12-30 years. We also selected an age and sex-matched control group. All measurements were performed on cross-sectional images obtained with cone-beam computed tomography. The selected areas of interest were the 4 interradicular spaces between the distal wall of the canine and the mesial wall of the second molar, in both maxillary quadrants. We measured the vestibular-palatine (VP) and mesiodistal (MD) dimensions to depths of 3, 6 and 9 mm from the alveolar ridge. We also measured the bone density in the same interradicular spaces of interest to 6 mm of depth from the alveolar crest. VP measurements were longer in the more posterior sectors and as the distance from the alveolar ridge increased. MD measurements also increased progressively as the distance from the alveolar ridge increased. In general, both the VP and MD measurements in the DS group were similar among the male and female participants. As age increased, the MD distance increased, while the VP distance decreased. The VP distance was ≥6 mm in at least 75% of the DS group in practically all assessed interdental spaces. The MD distance was ≥2 mm in at least 75% of the DS group only between the first and second molar, to 9 mm of depth from the alveolar ridge. The safe area for inserting orthodontic miniscrews in DS patients is restricted to the most posterior and deepest area of the maxillary alveolar bone.

Comparison of lateral approach versus anterolateral approach with Herbert screw fixation for isolated coronal shear fractures of humeral capitellum.

BACKGROUND: For coronal shear fractures of humeral capitellum, the lateral approach is the most commonly used surgical approach. However, exposure range of the anterior aspect of the distal humerus is inadequate. The anterolateral approach has also been adopted to overcome this disadvantage. However, this approach seems anatomically complex due to the risk of iatrogenic injury to the radial nerve. So far, the optimal approach for the treatment of capitellar shear fractures remains inconclusive. The purpose of this study is to prospectively review and compare the early clinical and radiographic outcomes of treated with open reduction and Herbert screw internal fixation through the lateral approach or the anterolateral approach. METHODS: Twenty-six patients with isolated capitellar shear fractures were enrolled from January 2013 to December 2017, and randomly assigned to lateral approach group or anterolateral approach group. All the fractures were treated with open reduction and Herbert screw internal fixation through lateral approach or anterolateral approach. Operation time, wound healing complication, elbow joint function, and radiographic evidence were evaluated and compared between two groups. RESULTS: The operation via the anterolateral approach took significantly shorter time than via lateral approach (p < 0.05). There were no wound healing problems and infection for both groups. One patient from anterolateral approach group sustained incomplete posterior interosseous nerve palsy, which recovered completely in 4 weeks without residual compromise. All fractures healed well in their normal anatomic position as seen on radiographs. At the final follow-up, no significant difference was found between two groups with respect to the ROM in supination-pronation, ROM in pronation-supination, loss of flexion-extension motion, or loss of pronation-supination motion (p > 0.05). There is no significant difference with respect to MEPI score of elbow joint between two groups (p > 0.05). CONCLUSION: Based on our findings, both lateral approach and anterolateral approach with Herbert screw internal fixation are suitable for coronal shear fractures of capitellum with satisfactory early outcomes. Compared with the lateral approach, the anterolateral approach made the surgical procedure easier and time saving in current series. When the medial aspect of the trochlea is involved for capitellar coronal fractures, the anterolateral lateral approach should be preferred.

Examining implant superiority in the treatment of simple pertrochanteric fractures of the proximal femur in elderly patients.

BACKGROUND: The aim of this study was to compare the clinical and radiological results of the proximal femoral nail antirotation (PFNA) with those of the dynamic hip screw (DHS) and percutaneous compression plate (PCCP) in the treatment of simple pertrochanteric fractures. METHODS: A total of 203 patients were included in the study. PFNA fixations were performed in 73 patients (PFNA group), DHS in 68 patients (DHS group), and PCCP in 62 patients (PCCP group). The main outcome measurements were perioperative properties, the Harris hip score, changes in the neck-shaft angle, and loss of the abductor muscle strength. Data were compared between the groups. RESULTS: The mean estimated total blood loss and the number of patients receiving the blood transfusion rate in the PFNA group were statistically significantly lower. The mean operation and fluoroscopy times in the PCCP group were statistically significantly higher. The mean loss of the abductor muscle strength and changes in the neck-shaft angle in the PFNA group were statistically significantly higher. The mean Harris hip scores were similar. CONCLUSION: Our findings demonstrated that although PFNA was superior with regard to the perioperative data, DHS and PCCP were superior in maintaining the reduction and the abductor muscle strenght. All three implants were similar and had satisfactory functional outcomes.

Evaluation of the long-term stability of micro-screws under different loading protocols: a systematic review.

The aim of this systematic review was to investigate the association between the different factors of loading protocols and the long-term stability of micro-screws from biomechanical and histological viewpoints. Searches were performed on PubMed, Embase, Cochrane Library, Wanfang and CNKI databases for animal experiments comparing loading protocols and the long-term stability of micro-screws. Among 1011 detected papers, 16 studies met the eligibility criteria and were selected for analysis. Most studies showed medium methodological quality for evaluation of micro-screws' long-term stability. Five studies reported that loading would not destroy the long-term stability of micro-screws. Three studies indicated that low-intensity immediate loading or a 3-week minimal healing time was acceptable. Two studies reported that the loading magnitude was a controversial issue with regard to the micro-screws' long-term stability. Two studies suggested that counterclockwise loading could decrease the long-term stability of micro-screws. In conclusion, immediate loading below 100g force, healing time greater than 3 weeks, regular loading below 200g force and a clockwise direction of force supported the long-term stability of micro-screws. Further studies relating to the combination of varying loading conditions will be needed.