Purpose of Study:. In situ fixation with cannulated screws, is the most common surgical management of Slipped Capital Femoral Epiphysis. Surgeons are wary of the consequences to the epiphysis with any manipulation of the hip. The purpose of this study, was to evaluate the use of a single cannulated screw, inserted with imaging done in the standard AP position, and gentle positioning for a frog lateral X-ray, and the risk of slip progression. Description:. A retrospective radiological review was done on 18 patients between the ages of 9–14 treated for unstable slips from 2006–2014. All patients were treated with a single partially threaded, cannulated screw inserted from the anterior aspect of the neck perpendicular to the epiphysis. Intraoperative imaging included an AP image, and thereafter the hip was gently abducted and externally rotated for a frog lateral view. Radiological comparison of the preoperative, postoperative and subsequent follow up X-rays was done. Follow up ranged from 6 months to 8 years. Results:. Radiographs showed no significant slip progression post op. Conclusion:. Gentle positioning for a frog lateral image during screw placement, and a single screw technique appears to be a safe in the management of unstable slips in Slipped Capital Femoral Epiphysis

Olecranon Osteotomy is a common approach used in the management of intraarticular distal humerus fractures. Significant complication rates have been associated with this procedure, including non-union rates of 0–13% and implant removal rates between 12–86%. This study is a multicentre retrospective study involving the largest cohort of olecranon osteotomies in the literature, examining implant fixation types, removal rates and associated complications. Patients were identified between 2007 and 2017 (minimum one year follow-up) via Canadian Classification of Health Interventions (CCI) coding and ICD9/10 codes by our health region's data information service. CCI intervention codes were used to identify patients who underwent surgery for their fracture with an olecranon osteotomy. Reasons for implant removal were identified from a chart review. Our primary outcome was implant removal rates. Categorical data was assessed using Chi square test and Fischer's Exact test. Ninety-nine patients were identified to have undergone an olecranon osteotomy for treatment of a distal humerus fracture. Twenty patients had their osteotomy fixed with a plate and screws and 67 patients were fixed with a tension band wire. Eleven patients underwent “screw fixation”, consisting of a single screw with or without the addition of a wire. One patient had placement of a cable-pin system. Of patients who underwent olecranon osteotomy fixation, 34.3% required implant removal. Removal rates were: 28/67 for TBW (41.8%), 6/20 plates (30%), 0/1 cable-pin and 0/11 for osteotomies fixed with screw fixation. Screw fixation was removed less frequently than TBW p<.006. TBW were more commonly removed than all other fixation types p<.043. Screws were less commonly removed than all other fixation types p<.015. TBW were more likely to be removed for implant irritation than plates, p<.007, and all other implants p<.007. The average time to removal was 361 days (80–1503 days). A second surgeon was the surgeon responsible for the removal in 10/34 cases (29%). TBWs requiring removal were further off the olecranon tip than those not removed p=.006. TBWs were associated with an OR of 3.29 (CI 1.10–9.84) for implant removal if implanted further than 1mm off bone. Nonunion of the osteotomy occurred in three out of 99 patients (3%). K-wires through the anterior ulnar cortex did not result in decreased need for TBW removal. There was no relation between plate prominence and the need for implant removal. There was no association between age and implant removal. The implant removal rate was 34% overall. Single screw fixation was the best option for osteotomy fixation, as 0/11 required hardware removal, which was statistically less frequent than TBW at 28/67. Screw fixation was removed less frequently than TBW and screw fixation was less commonly removed than all other fixation types. Only 6/20 (30%) plates required removal, which is lower than previously published rates. Overall, TBW were more commonly removed than all other fixation types and this was also the case if hardware irritation was used as the indication for removal. Nonunion rates of olecranon osteotomy were 3%

Cannulated screw is commonly used in the fixation of proximal femoral neck fractures. In the literature, several configurations had been proposed for best mechanical support with clinical experiences or biomechanical tests. Although screws in triangle configuration contribute certain fixation stability, but sometimes the surgeons made their own choices have to conduct another fixation pattern for some factors such as fracture type, economic issues, and so on. Therefore the aim of this study is to analyze the mechanical responses of a fractured femur fixed with screws in different configurations, screw materials and screw diameters with finite element method, trying to find the most stable construct. A solid femur model was built from the CT images of a standard saw bone. Three fracture types of the femoral neck were created according to Pauwel's classification (30?, 50?, 70?) by CAD software. The models of implanted screws were built according to a commercial cannulated screw (Stryker Osteosynthesis, Schoenkirchen/Kiel, Germany) with diameter 6.5mm and 4.5mm by CAD software, too. Three fixation configurations were analyzed in this study, including triangle with superior single screw with titanium diameter 6.5mm, triangle with inferior single screw with diameter 6.5mm and diamond with four stainless screw diameter 4.5mm (fig.1). Totally there were nine models constructed in this study, and all of them were then imported into ANSYS WORKBENCH v14 (Swanson Analysis, Houston, PA, USA) to mesh and further analysis. 700N vertical downward force was applied on the femur head and the distal end of femur shaft was totally fixed. The triangle fixation with superior single screw resulted in a best stability, but the fracture fixed with screws in a diamond configuration has least fracture gap. The difference of the maximum displacement of the femur head with Pauwel's classification 70?between triangle fixation with superior single screw and diamond configuration is only 0.03mm (1.72–1.69 mm). In most unstable femoral neck fracture [Pauwel's classification 70], the maximum gap distance is 0.59mm under the diamond configuration, while it is 0.63mm as the fracture fixed with a triangle configuration. Therefore, this study suggests that four 4.5mm stainless screws in a diamond configuration is an alternative for proximal femur fracture once 6.5mm titanium screws are not available

Dual plate constructs have become an increasingly common fixation technique for midshaft clavicle fractures and typically involve the use of mini-fragment plates. The goal of this technique is to reduce plate prominence and implant irritation, as these are common reasons for revision surgery. However, limited biomechanical data exist for these lower-profile constructs. The study aim was to compare dual mini-fragment orthogonal plating to traditional small-fragment clavicle plates for biomechanical non-inferiority and to determine if an optimal plate configuration could be identified, using a cadaveric model. Twenty-four cadaveric clavicles were randomized to one of six groups (n=4 per group), stratified by CT-based bone mineral content (BMC). The six different plating configurations compared were: pre-contoured superior or anterior fixation using a single 3.5-mm LC-DC plate, and four different dual-plating constructs utilizing 2.4-mm and 2.7-mm reconstruction or LC-DC plates. The clavicles were plated and then osteotomized to create an inferior butterfly fracture, which was then fixed with a single interfragmentary screw (OTA 15.2B). Axial, torsional, and bending (anterior and superior surface loading) stiffness were determined for each construct through non-destructive cyclic testing, using an MTS 858 Bionix materials testing system. This was followed by a load-to-failure test in three-point superior-surface bending. Kruskal-Wallace H and Mann-Whitney U were used to test for statistical significance. There were no significant differences in BMC (median 7.9 g, range 4.2-13.8 g) for the six groups (p=1.000). For axial stiffness, the two dual-plate constructs with a superior 2.4-mm and anterior 2.7-mm plate (either reconstruction or LC-DC) were significantly stiffer than the other four constructs (p=0.021). For both superior and anterior bending, the superior 2.4-mm and anterior 2.7-mm plate constructs were significantly stiffer when compared to the 3.5-mm superior plate (p=0.043). In addition, a 3.5-mm plate placed anterior was a stiffer construct than a superior 3.5-mm plate (p=0.043). No significant differences were found in torsional stiffness or load-to-failure between the different constructs. Dual plating using mini-fragment plates is biomechanically superior for fixation of midshaft clavicle fractures when compared to a single superior 3.5-mm plate and has similar biomechanical properties to a 3.5-mm plate placed anteriorly. With the exception of axial stiffness, no significant differences were found when different dual plating constructs were compared to each other. However, placing a 2.4-mm plate superiorly in combination with a 2.7-mm plate anteriorly might be the optimal construct, given the biomechanical superiority over the 3.5-mm plate placed superior

In posterior fixation for deformity correction and spinal fusion, there is increasing discussion around auxiliary rods secured to the pedicle screws, sharing the loads, and reducing stresses in the primary rods. Dual-rod, multiaxial screws (DRMAS) provide two rod mounting points on a single screw shaft to allow unique constructs and load-sharing at specific vertebrae. These implants provide surgical flexibility to add auxiliary rods across a pedicle subtraction osteotomy (PSO) or over multiple vertebral levels where higher bending loads are anticipated in primary rods. Other options include fixed-angle devices as multiple rod connectors (MRC) and variable-angle dominoes (VAD) with a single-axis rotation in the connection. The objective in this simulation study was to assess rod bending in adult spinal instrumentation across an osteotomy using constructs with DRMAS, MRC, or VAD multi-rod connections. The study was performed using computer biomechanical models of two adult patients having undergone posterior instrumented spinal fusion for deformity. The models were patient-specific, incorporating the biomechanics of the spine, have been calibrated to assess deformity correction and intra- and postoperative loads across the instrumented spine. One traditional bilateral-rod construct was used as a control for six multi-rod configurations. Spinal fixation scenarios from T10 through S1 with the PSO at L4 were simulated on each patient-specific model. The multi-rod configurations were bilateral and unilateral DRMAS at L2 through S1 (B-DRMAS and U-DRMAS), bilateral DRMAS at L3 and L5 (Hybrid), bilateral MRC over L3-L5, bilateral and unilateral VAD over L3-L5 (B-VAD and U-VAD). Postoperative gravity plus 8-Nm flexion and extension loads were simulated and bending moments in the rods were computed and compared. In the simulated control for each case (#1 & #2), average rod bending moments (of the right and left rods) at the PSO level were 6.7Nm & 5.5Nm, respectively, in upright position, 8.8Nm & 7.3Nm in 8-Nm flexion, and 4.6Nm & 3.7Nm in 8-Nm extension. When the primary rods of the multi-rod constructs were normalized to this control, the bending moments in the primary rods of Case #1 & #2 were respectively 57% & 58% (B-DRMAS), 54% & 62% (B-VAD), 60% & 61% (MRC), 72% & 69% (Hybrid), 81% & 70% (U-DRMAS), and 81% & 73% (U-VAD). Overall, the reduction in primary rod bending moments ranged from 19–46% for standing loads. Under simulated 8-Nm functional moments, the primary rod moments were reduced by 18–46% in flexion and 17–48% in extension. More rods and stiffer connections produced the largest reductions for the primary rods, but auxiliary rods had bending moments that varied from 49% lower to 13% higher than the primary ones. Additional rods through DRMAS, MRC, and VAD connections noticeably reduced the bending loads in the primary rods compared with a standard bilateral-rod construct. Yet, bending loads in the auxiliary rods were higher or lower than those in the primary rods depending on the 3D spinal deformity and stiffness of the auxiliary rod connections. Additional studies and patient-specific analyses are needed to optimize instrumentation parameters that may improve load-sharing in these constructs

Minimally invasive placement of iliosacral screws (SI-screw) is becoming the standard surgical procedure for sacrum fractures. Computer navigation seems to increase screw accuracy and reduce intraoperative radiation compared to conventional radiographic placement. In 2012 an interdisciplinary hybrid operating theatre was installed at the University of Ulm. A floor-based robotic flat panel 3D c-arm (Artis zeego, Siemens, Germany) is linked to a navigation system (BrainLab Curve, BrainLab, Germany). With a single intraoperative 3D scan the whole pelvis can be visualised in CT-like quality. The aim of this study was to analyse the accuracy of SI-screws using this hybrid operating theater. 32 SI-screws (30 patients) were included in this study. Indications ranged from bone tumour resection with consecutive stabilisation to pelvic ring fractures. All screws were implanted using the hybrid operating theatre at the University of Ulm. We analysed the intraoperative 3D scan or postoperative computed tomography and classified the grade of perforation of the screws in the neural foramina and the grade of deviation of the screws to the cranial S1 endplate according to Smith et al. Grade 0 stands for no perforation and a deviation of less than 5 °. Grade 1 implies a perforation of less than 2 mm and a deviation of 5–10°, grade 2 a perforation of 2–4 mm and a deviation of 10–15° and grade 3 a perforation of more than 4 mm and a deviation of more than 15°. All patients were tested for intra- and postoperative neurologic complications and infections. The statistical analysis was executed using Microsoft Excel 2010. 32 SI-screws were implanted in the first 20 months after the hybrid operating theatre had been established in 2012. All 30 patients were included in this study (15 men, 15 women). The mean age was 59 years ±23 (13–95 years). 20 patients received a single screw in S1 (66.7%), 1 patient 2 unilateral screws in S1 and S2 (3.3%), one patient 2 bilateral screws in S1 (3.3%) and 8 patients a single screw stabilising both SI-joints (26.7%). 27 screws showed no perforation (84.4%), 1 screw a grade 1 perforation (3.1%) and 4 screws a grade 2 perforation (12.5%). There was no grade 3 perforation. Furthermore there was no perforation of the neural foramina or the ventral cortex in the axial plane of the SI-screws stabilising one SI-joint (24 screws). Only single SI-screws bridging both SI joints showed a perforation of the neural foramina (37% grade 0, 12.5% grade 1, 50% grade 2, 0% grade 3). In the frontal plane 23 screws (71.9%) showed a deviation of less than 5°. In 5 screws a grade 1 deviation (15.6%) and in 4 screws a grade 2 deviation (12.5%) could be found. There was no grade 3 deviation. There were no infections or neurological complications. The high image quality and large field of view in combination with an advanced navigation system is a great benefit for the surgeon. All SI-screws stabilising only one joint showed completely intraosseous placement. Single SI-screws bridging 2 SI-joints intentionally perforated the neural foramina ventrally in 5 cases because of dysmorphic sacral anatomy. This makes image-guided implantation of SI-screws in a hybrid operating theatre a very safe procedure

Introduction. Surgeons fixing scaphoid fractures need to be familiar with its morphological variations and their implications on safe screw placement during fixation of these fractures. Literature has limited data in this regard. The purpose of this CT-based study was to investigate scaphoid morphometry and to analyse the safe trajectories of screw placement in scaphoid. Methods. We measured the coronal and Sagittal widths of scaphoid in CT-scans of 60 patients using CT based data from 50 live subjects with intact scaphoid. Safe placements for screws with diameters of 1.7mm, 2.4mm, 3.5mm and 4mm were studied using trajectories with additional 2mm safety corridor. Results. The mean width of proximal segment in coronal and sagittal plane were 6.39mm (4.5–8.7) and 11.44mm (8.4–14.1) respectively. For the waist region, the mean coronal, sagittal width were 8.03mm (6.3–10.2mm) and 9.02mm (7–11.4mm) respectively. For distal segment, the mean coronal and sagittal width were 10.58mm (8.2–14.6mm) and the 9.59mm (7.3–11.9mm) respectively. The coronal and sagittal widths were significantly different from each other in all three zones. All scaphoid were capable of safely containing single 4mm screw and two parallel 1.7mm screws. Conclusion. Our study shows that there is considerable variation in scaphoid morphometry. Among the parameters, the waist region measurements show the least variation. The screw lengths do not always correlate to the overall longitudinal extent of scaphoid and can be planned preoperatively using CT-scans. Surgeons treating these fractures should opt for a CT-based analysis regarding the screw direction and length and need to be familiar with the variations in scaphoid morphometry

The common practice for insertion of distal locking screws of intramedullary (IM) nails is a freehand technique under fluoroscopic control. The process is technically demanding, time-consuming and afflicted to considerable radiation exposure to patient and surgical personnel. A new technique is introduced which guides the surgeon by landmarks on the X-ray projection. 18 fresh frozen human below-knee specimens (incl. soft tissue) were used. Each specimen was instrumented with an Expert Tibial Nail (Synthes GmbH, Switzerland) and was mounted on an OR-table. Two distal interlocking techniques were performed in random order using a Siemens ARCADIS C-arm system (Siemens AG, Munich, Germany). The newly developed guided technique, guides the surgeon by visible landmarks projected onto the fluoroscopy image. A computer program plans the drilling trajectory by 2D-3D conversion and provides said guiding landmarks for drilling in real-time. No additional tracking or navigation equipment is needed. All four distal screws (2 mediolateral, 2 anteroposterior) were placed in each procedure. Operating time, number of taken X-rays and radiation time were recorded per procedure and for each single screw. 8 procedures were performed with the freehand technique and 10 with the guided technique. A 58% reduction in number of fluoroscopy shots per screw was found for the guided technique (7.4±3.4 vs. 17.6±10.3; p < 0.001). Total radiation time was 55% lower for the guided technique (17.1 ± 3.7s vs. 37.9 ± 9.1s) (p = 0.001). Operating time was shorter by 22% in the guided technique (3.2±1.2 min vs. 4.1±2.1 min p = 0.018). In an experimental setting, the newly developed guided freehand technique has proven to markedly reduce radiation exposure when compared to the conventional freehand technique. The method enhances established clinical workflows and does not require cost intensive add-on devices or extensive training. A newly developed simple navigated technique has proven to markedly reduce radiation exposure and time for distal locking of intramedullary nails

Introduction. Scaphoid fractures are commonly treated with a single headless screw. There are different recommendations regarding the optimal location of this screw. The purpose of this study was to compare the location of screws placed for the treatment of acute scaphoid fractures with theoretical and virtual screw locations. Materials and Methods. 10 patients with acute scaphoid fractures treated surgically and with available pre- and postoperative CT scans were included. The scans were analysed using a 3D software model (Amira Dev 5.3, Mercury Computer Systems, Chelmsford, MA). On the preoperative CTs the displaced fractures were virtually reduced. Possible screw locations for fracture fixation were examined including one along the central third of the proximal fragment (central base screw), the scaphoid longitudinal axis calculated mathematically (PCA screw) and a screw placed perpendicular to the fracture plane (90 degree screw). The angle between the axes and fracture plains were measured. The angle and distance between the actual screw on the postoperative CT and the different virtual screw locations were measured as well. Results. The angles between the actual and virtual screws to the fracture plane were between a mean of 67 to 69 degrees. The angle between the axes was greatest between the 90 degree screws to the PCA and actual screws (mean 23 degrees both; p=0.034) and smallest between the central base screws and PCA to the actual screws (mean of 12.1 and 12.5 degrees, respectively; p=0.034). The difference between the entrance and exit points between the axes was between 3.1 to 4.8 mm other than the 90 degree screws which were 5.3 to 7.1 mm to the other axes (p=0.002). The PCA (mean 28.3 mm) were found to be longer than the actual screws (mean 25.4) or the 90 degree screws (mean 23.5) (p=0.034 and p=0.008 respectively). The 90 degree screws were shorter than the PCA or central base screws (p=0.008, p=0.034 respectively), but not the actual screws. Discussion. There were no significant differences in the angles between actual and virtual optimal screws other than the 90 degree screws. The PCA was found to be the longest screw and at a similar angle to the fractures as the other virtual screw options, other than the shorter 90 degree screw. Virtual reduction and preplanning of the screw location, using standard software, may enable the surgeon to place the longest screw along the PCA longitudinal axis. If placing a 90 degree screw is considered, this may be technically difficult or may necessitate a trans-trapezial approach

The consequences of the complications associated with the management of slipped upper femoral epiphysis are a major source of disability in young adults. Whilst the management of chondrolysis, avascular necrosis or malunion of the femoral neck is usually undertaken by paediatric orthopaedic surgeons the initial management of SUFE in many regions is as part of an adult trauma service. This retrospective audit assessed the outcome of the management of SUFE in one such health region in which treatment occurred at three sites by a number of surgeons of varying experience, during the period July 1994 to June 2004. The aim was to compare our outcomes with those published and to identify whether our service should be altered as a consequence. The case notes and x-rays as recorded in theatre records were retrieved. Of the 64 cases that were treated during this period adequate records for 60 patients were available. Of these 60 patients there were 7 bilateral cases. Fixation in all 67 cases was by a single cannulated screw. In the 53 unilateral cases 17 underwent prophylactic pinning, the remaining 36 remained under observation. Of these nine patients presented with subsequent slips, eight of which were unstable and two had slip angles greater than 60° in which one developed avascular necrosis. Four other cases of avascular necrosis were observed (incidence 6%). Chondrolysis occurred in one patient with persistent pin penetration. In the remaining 73 cannulated screws used for stabilisation and 17 for prophylactic fixation no complications were observed. The complication rates observed in this series are within those accepted in the literature. The high incidence of subsequent slips and the attendant severity of these when compared with the relative safety of contemporary cannulated screw fixation has led us to recommend prophylactic pinning in our region

INTRODUCTION. Isolated injuries of the sacral bone are rare. The pathomechanism of these injuries are usually high velocity accidents or falls from large heights. The computer-assisted implantation of iliosacral screws (SI-screw) becomes more important in the treatment of dorsal pelvic ring fractures. The advantage of the minimal-invasive screw placement is the reduction of the non-union and deep wound infection rate. Another advantage of computer-navigated SI-screw placement is the reduction of intraoperative radiation for the patient and the surgical staff. The purpose of this study was to analyse the position of navigated iliosacral screws. METHODS. In the study group 74 screws (49 patients) were included and radiologically analysed. All screws were implanted using 3D-navigation (BrainLAB Vector Vision, Brainlab, Germany). Navigation was always executed with the same 3D c-arm (ARCADIS Orbic 3D, Siemens, Germany) and navigation system. We determined the grade of perforation and angular deviation in the postoperative CT-scans in all screws. The classification was performed according to Smith et al in 4 grades. Grade 0 implies no perforation and grade 1 a perforation less than 2 mm. Grade 2 correlates a perforation of 2–4 mm and grade 3 a perforation of more than 4 mm. Furthermore the intra- and postoperative complications as well as the body-mass-index, the co-morbidities and the duration of radiation were documented. The statistical analysis was executed using Microsoft Excel 2003. RESULTS. The mean age of the 49 patients was 42.2 years ± 18 (16–79 years). 28 male and 21 female patients were included. 25 patients received a single iliosacral screw in S1. In 19 cases a screw in S1 and S2 was placed on the same side. Four patients got bilateral SI-screws in S1 and another patient received bilateral screw placement in S1 as well as an additional screw in S2. The mean operation time was 100 min ±103 (20–540 min). The isolated time for SI-placement was 50 min ± 20 (20–93 min). The mean radiation time was 3 min ± 1.7 (0.9–7.4 min) (n = 28). Altogether 84% of the screws showed an intraosseous position (grade 0). In the axial plane 7 screws perforated ventrally, 5 screws penetrated the adjacent neural foramen. In the frontal plane the screws showed greater variations, 61% deviated less than 5° (grade 0). In the study group 5 screws needed surgical revision because of either malplacement or postoperative pain. There were no infections or neurological complications. There was no statistical correlation between screw perforation and the body-mass-index. CONCLUSION. The computer-assisted implantation of iliosacral screws is a safe method in relation to screw perforation. It shows a high security and accuracy concerning the ventral and dorsal cortical perforation. There is a frequent angular deviation in the frontal view without appearance of screw perforation or mechanic, neurologic and angiologic complications. The minimal-invasive procedure shows a low postoperative revision rate