Aims. In UK there are around 76,000 hip fractures occur each year 10% to 15% of which are undisplaced intracapsular. There is considerable debate whether internal fixation is the most appropriate treatment for undisplaced fractures in older patients. This study describes cannulated hip screws survivorship analysis for patients aged ≥ 60 years with undisplaced intra-capsular fractures. Methods. This was a retrospective cohort study of consecutive patients aged ≥ 60 years who had cannulated screws fixation for Garden I and II fractures in a teaching hospital between March 2013 and March 2016. The primary outcome was further same-side hip surgery. Descriptive statistics were used and Kaplan-Meier estimates calculated for implant survival. Results. A total of 114 operations were performed on 112 patients with a mean age of 80.2 years (SD 8.9). The 30-day and one-year mortality were 1% (n = 1) and 13% (n = 15), respectively. Median follow-up was 6.6 years (interquartile range 6.0 to 7.3). Kaplan-Meier estimates showed a survivorship of 95% at one year and 90% at five years (95% confidence interval 84% to 95%) for cannulated screws. Nine patients underwent further hip surgery: four revision to total hip arthroplasty, one revision to hemiarthroplasty, three removals of screws, and one haematoma washout. Posterior tilt was assessable in 106 patients; subsequent surgery was required in two of the six patients identified with a posterior angle > 20° (p = 0.035 vs angle < 20°). Of the 100 patients with angle < 20°, five-year survivorship was 91%, with seven patients requiring further surgery. Conclusion. This study of cannulated hip screw fixation for undisplaced fractures in patients aged ≥ 60 years reveals a construct survivorship without further operation of 90% at five years. Cannulated screws can be considered a safe reliable treatment option for Garden I and II fractures. Caution should be taken if posterior tilt angle on lateral view exceeds 20°, due to a higher failure rate and reoperation, and considered for similar management to Garden III and IV injuries. Cite this article: Bone Jt Open 2022;3(3):182–188

Objectives. This presentation discusses the experience at our Centre with treating traumatic thoracolumbar fractures using percutaneous pedicle screw fixation and also looks at clinical and radiological outcomes as well as complications. Design. This is a retrospective study reviewing all cases performed between Jan 2013 and June 2019. Subjects. In our study there were 257 patients in total, of which there were 123 males and 134 females aged between 17 and 70. Methods. We reviewed the case notes and imaging retrospectively to obtain the relevant data. Results. A total of 257 patients were included, 123 males and 134 females; the mean age was 47.6 years. The majority of injuries were from fall from significant height. In 98 cases the fracture involved a thoracic vertebra and in 159 cases a lumbar vertebra. Percutaneous pedicle screw fixation was performed either one level above and below fracture or Two levels above and below the fracture depending upon the level of injury. Forty two cases were treated with additional short pedicle screws at the level of fracture. More than 15% (39) of patients presented with a neurological deficit on admission and more than 80% (32) of those showed post-operative improvement in their neurology as per Frankel Grading system. The mean Operative time was 117minutes +− 45, and mean length of hospital stay was 7.2 +− 3.8 days, with significant improvement in Visual analogue score. Percutaneous fixation achieved a satisfactory improvement in radiological parameters including sagittal Cobb angle (SCA) post-operatively in all patients. The vast majority of patients achieved a good functional outcome according to modified Macnab criteria. Follow up was for a maximum of two years, with relevant imaging at each stage. Ten (3.8%) patients had wound infection with three patients requiring wound debridement. Four patients had upper level screws pulled out and in Four cases one screw was misplaced. All eight had revision surgery. Conclusions. Percutaneous pedicle screw fixation is a safe surgical option with comparable outcomes to open surgery and a potential reduction in perioperative morbidity. Percutaneous pedicle screw fixation is the primary surgical technique to treat traumatic thoracolumbar fractures at our Centre. There were no major complications in our series, with good functional outcome following surgery

Abstract. Introduction. Tibial tubercle osteotomy (TTO) is a complex surgical procedure with a significant risk of complications, which include nonunion and tibial fracture. To determine whether an additional suture tape augmentation can provide better biomechanical stability compared with standard screw fixation. Methods. Five matched pairs of human cadaveric knees were divided into 2 groups: the first group underwent standard TTO fixation with 2 parallel screws. The second group underwent a novel fixation technique, in which a nonabsorbable suture tape (FiberTape) in a figure-of-8 construct was added to the standard screw fixation. Tubercular fragment migration of >50% of the initial distalization length was defined as clinical failure Tubercular fragment displacement during cyclic loading and pull-to-failure force were recorded and compared between the 2 groups. Results. The augmented group showed less cyclic tubercular fragment displacement after every load level compared with the standard group, with statistically significant differences starting from 500 N (P < .05; power > 0.8). Mean ± standard deviation tubercular fragment displacement at the end of cyclic loading was 2.56 ± 0.82 mm for the augmented group and 5.21 ± 0.51 mm for the standard group. Mean ultimate failure load after the pull-to-failure test was 2475 ± 554 N for the augmented group and 1475 ± 280 N for the standard group. Conclusion. The specimens that underwent suture tape augmentation showed less tubercular fragment displacement during cyclic loading and higher ultimate failure forces compared with those that underwent standard screw fixation

The use of intraoperative navigation and robotic surgery for minimally invasive lumbar fusion has been increasing over the past decade. The aim of this study is to evaluate postoperative clinical outcomes, intraoperative parameters, and accuracy of pedicle screw insertion guided by intraoperative navigation in patients undergoing lumbar interbody fusion for spondylolisthesis. Patients who underwent posterior lumbar fusion interbody using intraoperative 3D navigation since December 2021 were included. Visual Analogue Scale (VAS), Oswestry Disability Index (ODI), and Short Form Health Survey-36 (SF-36) were assessed preoperatively and postoperatively at 1, 3, and 6 months. Screw placement accuracy, measured by Gertzbein and Robbins classification, and facet joint infringement, measured by Yson classification, were assessed by intraoperative Cone Beam CT scans performed at the end of instrumentation. Finally, operation time, intraoperative blood loss, hospital stay, and screw insertion time were evaluated. This study involved 50 patients with a mean age of 63.7 years. VAS decreased from 65.8±23 to 20±22 (p<.01). ODI decreased from 35.4%±15 to 11.8%±14 (p<.01). An increase of SF-36 from 51.5±14 to 76±13 (p<.01) was demonstrated. The accuracy of “perfect” and “clinically acceptable” pedicle screw fixation was 89.5% and 98.4%, respectively. Regarding facet violation, 96.8% of the screws were at grade 0. Finally, the average screw insertion time was 4.3±2 min, hospital stay was 4.2±0.8 days, operation time was 205±53 min, and blood loss was 169±107 ml. Finally, a statistically significant correlation of operation time with hospital stay, blood loss and placement time per screw was found. We demonstrated excellent results for accuracy of pedicle screw fixation and violation of facet joints. VAS, ODI and SF-36 showed statistically significant improvements from the control at one month after surgery. Navigation with intraoperative 3D images represents an effective system to improve operative performance in the surgical treatment of spondylolisthesis

Aims. The optimal management of posterior malleolar ankle fractures, a prevalent type of ankle trauma, is essential for improved prognosis. However, there remains a debate over the most effective surgical approach, particularly between screw and plate fixation methods. This study aims to investigate the differences in outcomes associated with these fixation techniques. Methods. We conducted a comprehensive review of clinical trials comparing anteroposterior (A-P) screws, posteroanterior (P-A) screws, and plate fixation. Two investigators validated the data sourced from multiple databases (MEDLINE, EMBASE, and Web of Science). Following PRISMA guidelines, we carried out a network meta-analysis (NMA) using visual analogue scale and American Orthopaedic Foot and Ankle Score (AOFAS) as primary outcomes. Secondary outcomes included range of motion limitations, radiological outcomes, and complication rates. Results. The NMA encompassed 13 studies, consisting of four randomized trials and eight retrospective ones. According to the surface under the cumulative ranking curve-based ranking, the A-P screw was ranked highest for improvements in AOFAS and exhibited lowest in infection and peroneal nerve injury incidence. The P-A screws, on the other hand, excelled in terms of VAS score improvements. Conversely, posterior buttress plate fixation showed the least incidence of osteoarthritis grade progression, postoperative articular step-off ≥ 2 mm, nonunions, and loss of ankle dorsiflexion ≥ 5°, though it underperformed in most other clinical outcomes. Conclusion. The NMA suggests that open plating is more likely to provide better radiological outcomes, while screw fixation may have a greater potential for superior functional and pain results. Nevertheless, clinicians should still consider the fragment size and fracture pattern, weighing the advantages of rigid biomechanical fixation against the possibility of soft-tissue damage, to optimize treatment results. Cite this article: Bone Jt Open 2024;5(3):227–235

Custom acetabular components have become an established method of treating massive acetabular bone defects in hip arthroplasty. Complication rates, however, remain high and migration of the cup is still reported. Ischial screw fixation (IF) has been demonstrated to improve mechanical stability for non-custom, revision arthroplasty cup fixation. We hypothesise that ischial fixation through the flange of a custom acetabular component aids in anti-rotational stability and prevention of cup migration. Electronic patient records were used to identify a consecutive series of 49 custom implants in 46 patients from 2016 to 2022 in a unit specializing in complex joint reconstruction. IF was defined as a minimum of one screw inserted into the ischium passing through a hole in a flange on the custom cup. The mean follow-up time was 30 months. IF was used in 36 cups. There was no IF in 13 cups. No difference was found between groups in age (68.9 vs. 66.3, P = 0.48), BMI (32.3 vs. 28.2, P = 0.11) or number of consecutively implanted cups (3.2 vs. 3.6, P = 0.43). Aseptic loosening with massive bone loss was the primary indication for revision. There existed no difference in Paprosky grade between the groups (P = 0.1). 14.2% of hips underwent revision and 22.4% had at least one dislocation event. No ischial fixation was associated with a higher risk of cup migration (6/13 vs. 2/36, X2 = 11.5, P = 0.0007). Cup migration was associated with an increased risk for all cause revision (4/8 vs. 3/38, X2 = 9.96, P = 0.0016, but not with dislocation (3/8 vs. 8/41, X2 = 1.2, P = 0.26). The results suggest that failure to achieve adequate ischial fixation, with screws passing through the flange of the custom component into the ischium, increases the risk of cup migration, which, in turn, is a risk factor for revision

Aims. Anchorage of pedicle screw rod instrumentation in the elderly spine with poor bone quality remains challenging. Our study aims to evaluate how the screw bone anchorage is affected by screw design, bone quality, loading conditions, and cementing techniques. Methods. Micro-finite element (µFE) models were created from micro-CT (μCT) scans of vertebrae implanted with two types of pedicle screws (L: Ennovate and R: S. 4. ). Simulations were conducted for a 10 mm radius region of interest (ROI) around each screw and for a full vertebra (FV) where different cementing scenarios were simulated around the screw tips. Stiffness was calculated in pull-out and anterior bending loads. Results. Experimental pull-out strengths were excellently correlated to the µFE pull-out stiffness of the ROI (R. 2. > 0.87) and FV (R. 2. > 0.84) models. No significant difference due to screw design was observed. Cement augmentation increased pull-out stiffness by up to 94% and 48% for L and R screws, respectively, but only increased bending stiffness by up to 6.9% and 1.5%, respectively. Cementing involving only one screw tip resulted in lower stiffness increases in all tested screw designs and loading cases. The stiffening effect of cement augmentation on pull-out and bending stiffness was strongly and negatively correlated to local bone density around the screw (correlation coefficient (R) = -0.95). Conclusion. This combined experimental, µCT and µFE study showed that regional analyses may be sufficient to predict fixation strength in pull-out and that full analyses could show that cement augmentation around pedicle screws increased fixation stiffness in both pull-out and bending, especially for low-density bone. Cite this article: Bone Joint Res 2021;10(12):797–806

Introduction. Intraoperative navigation systems for lumbar spine surgery allow to perform preoperative planning and visualize the real-time trajectory of pedicle screws. The aim of this study was to evaluate the deviation from preoperative planning and the correlations between screw deviation and accuracy. Method. Patients affected by degenerative spondylolisthesis who underwent posterior lumbar interbody fusion using intraoperative 3D navigation since April 2022 were included. Intraoperative cone-beam computed tomography (CBCT) was performed before screw planning and following implantation. The deviation from planning was calculated as linear, angular, and 3D discrepancies between planned and implanted screws. Accuracy and facet joint violation (FJV) were evaluated using Gertzbein-Robbins system (GRS) and Yson classification, respectively. Statistical analysis was performed using SPSS version28. One-way ANOVA followed by Bonferroni post-hoc tests were performed to evaluate the association between GRS, screw deviation and vertebral level. Statistical significance was set at p<0.05. Result. This study involved 34 patients, for a total of 154 pedicle screws. Mean age was 62.6±8.9 years. The mean two-dimensional screw tip deviation in mediolateral (ML), craniocaudal (CC), and anteroposterior (AP) was 2.6±2.45mm, 1.6±1.7mm, and 3.07±2.9mm, respectively. The mean screw tip 3D deviation was 5±3.3mm. The mean two-dimensional screw head deviation in ML, CC and AP was 1.83±1.8mm, 1.7±1.67mm and 3.6±3.1mm, respectively. The mean screw head 3D deviation was 4.94±3.2mm. 98% of screws were clinically acceptable (grade A+B), and grade 0 for FJV. Significant results were found between GRS and ML (p=0.005), AP (p=0.01) and 3D (p=0.003) tip deviations, and between GRS and AP and 3D head deviations (both p=0). Moreover, a significant correlation was found between GRS and vertebral level (p=0). Conclusion. Our results showed a reasonable rate of discrepancy between planned and positioned screws. However, accuracy was clinically acceptable in almost all cases. Therefore, pedicle screw fixation using intraoperative CBCT, 3D navigation and screw planning is safe and accurate

Abstract. Objectives. The principle of osteoporotic vertebral compression fracture (OVCF) is fixing instability, providing anterior support, and decompression. Contraindication for vertebroplasty is anterior or posterior wall fracture. The study objectives was to evaluate the efficacy and safety of vertebroplasty with short segmented PMMA cement augmented pedicle screws for OVCF with posterior/anterior wall fracture patients. Methods. A retrospective study of 24 patients of DGOU type-4 (vertebra plana) OVCF with posterior/anterior wall fracture, were treated by vertebroplasty and short segment PMMA cement augmented pedicle screws fixation. Radiological parameters (kyphosis angle and compression ratio) and clinical parameters Visual analogue scale (VAS) and Oswestry disability index (ODI) were analysed. Results. A significant improvement was noted in VAS (preoperative, 7.90 ±0.60; final follow-up 2.90 ± 0.54) and ODI (77.10 ± 6.96 to 21.30 ± 6.70), (P < 0.05). Neurological improvement was noted in all patients. Kyphosis corrected significantly from preoperative 23.20±5.90 to 5.30±1.40 postoperative with 5% (3.30± 2.95) loss of correction at final follow-up. Anterior vertebral height restored significantly from 55.80±11.9% t0 87.6±13.1% postoperative with 4.5±4.0% loss at final follow-up. One case had cement leakage was found, but the patient is asymptomatic. No implant-related complication was seen. No iatrogenic dural or nerve injury. Conclusions. Treatment with vertebroplasty with cement augmented screw fixation and direct decompression is a great option in treating such a complex situation in fragile age with fragile bones because It provides anterior support with cementing that avoids corpectomy. Short segment fixation has less stress risers at the junctional area

Purposes: To evaluate the validity of pedicle screw fixation in 20 patients with toracolumbar spine infections. Methods and Materials: There were seven tuberculous and thirteen pyogenic infection, eight had thoracic and 12 had lumbar lesion. The indications for surgical treatment were; progressive bone destruction, mal-alignment or neurological deficit. On nine cases, we did two-step operation, which was bone graft from anterior and pedicle screw fixation from posterior. On 11 cases, we did debridement, interbody graft and the pedicle screw fixation from posterior simultaneously. We examined the outcomes of the infection, symptoms including neurological deficit and the graft bones postoperatively with follow-up period of 25 months in the average. We also examined changes of alignment after surgery and surgical complications as well to evaluate the validity of the surgery. Results: Fusion of graft were confirmed in all cases within seven and half months in the average. Clinically, all of 14 patients who had had paraparesis gained neurological recovery of one or two steps of Frankel’s criteria after the surgery. Complications were, fracture of graft, fracture of vertebral body, screw loosening with alignment deterioration and recurrence of infection in one case each. Summary: Pedicle screw fixation revealed a usefulness in surgical treatment of spine infection

Over 2 years, 14 patients with C1/2 instability underwent posterior transarticular screw fixation. Pathologies included atlanto-axial subluxation in five rheumatoid patients, atlanto-axial rotatory subluxation and an odontoid fracture in two patients with ankylosing spondylitis, nonunion of odontoid fractures in three patients, three transverse ligament injuries and one type-III odontoid fracture. This study aimed to assess the use of transarticular screw fixation in terms of technique, union rates and functional outcomes. All operations were performed on a Relton-Hall frame with a Mayfield clamp and lateral fluoroscopy. The mean age of the eight men and six women was 48 years. The mean operation time was 112 minutes (65 to 225) and mean blood loss was 270 ml (150 to 700). Autologous posterior iliac crest bone graft was used in all patients. The procedure was aborted in one patient because of difficulty with reduction and screw angulation and in another because of excessive bleeding from the drill hole. Alternative fixation techniques were used in these two patients. All patients wore a Philadelphia collar postoperatively until stability was confirmed. The time to radiological union was 8 to 10 weeks. Clinical outcomes revealed full ranges of flexion and extension in most patients, with a 50% decrease in cervical rotation. There were no neurological complications postoperatively. There was implant failure in one patient, with screw breakage evident at follow-up, but this patient went on to union without further intervention. Transarticular screw fixation is an inexpensive, effective and safe technique for management of C1/2 instability

Introduction. Hindfoot intramedullary nail fixation (HFN) or fibula pro-tibial screw fixation (PTS) are surgical options for ankle fractures in patients with multiple co-morbidities; we compared their outcomes. Methods. A retrospective review of 135 patients who underwent HFN fixation (87 patients) or PTS fixation (48 patients) for ankle fractures (AO/OTA A/B/C) from 5 major trauma centres. Patient demographic data, co-morbidities, Charlson Co-morbidity Index Score (CCIS), weight-bearing, and post-operative complications were recorded. Radiographs were assessed for non-union and anatomical reduction. Results. HFN estimated 10-year survival was 27±31% and was 48±37% for PTS (p<0.001). Average time to full weightbearing (FWB) in the HFN group was 1.7±3.3 weeks compared to 7.8±3.8 weeks in the PTS group (p<0.001). Despite this, HFN fixation carried a greater VTE risk (p=0.02). HFN accompanied by joint preparation had greater risk of infection (p=0.01), metalwork failure (p=0.02) and wound breakdown (p=0.01). The overall complication rate in diabetic patients was 56%, but 76% in HFN patients. In the HFN group 17 (20%) patients died at 1 year. Patients with open fractures(p=0.01), dementia (p<0.05), and a higher CCIS (p=0.04) were more likely to die after HFN surgery. Age and co-morbidity matched data showed a higher rate of complications and mortality in those above 75 years fixed with a HFN, irrespective of CCIS. In those between 60–75 years, there was a greater risk of superficial infection and mortality after HFN, irrespective of CCIS. These complications were not seen after PTS. Conclusion. HFN carries a greater risk of superficial infections, VTE and mortality compared to PTS, independent of age and CCIS. Diabetes leads to a greater comparative risk of deep infections, wound breakdown and non-union in HFN. Alternative methods of fixation (e.g. PTS) should be considered before HFN. HFN may be suitable in selective indications where other methods are not appropriate

Background. The cementless acetabular component fixed with several screws is one of the most widely used approaches in THA. These screws rely on contact pressure and the resultant friction between the screw head and the cup to control translation and angulation of the prosthesis. However, intraoperative change of the acetabular component alignment during screw fixation should be hardly detected. Acetabular component alignment can be assessed using computer-assisted navigation systems with realtime adjustments for component position. The purpose of the current study was to evaluate intraoperative change of acetabular component alignment during screw fixation using navigation system. Patients and Methods. Primary THAs were performed in 74 hips using CT based fluoroscopic matching navigation system (VectorVision, BrainLAB). The patients were 18 men and 56 women with a mean age of 64.4 years (range, 47–78 years) at operation. Intraoperative acetabular component inclination and anteversion were measured at the time of press-fit, and after screw fixation using the cup verification function in the system. Mean of the absolute difference between at the time of press-fit and after screw fixation was evaluated as intraoperative change of acetabular component. We measured the distance from the center of the femoral head to the inter-teardrop line as a horizontal and vertical reference on the postoperative radiograph. The number of screws was also investigated. Results. Mean inclination and anteversion at the time of press-fit were 40.6° ± 3.6° and 14.6° ± 9.3°, respectively. Mean inclination and anteversion after screw fixation were 40.7° ± 4.4° for inclination and 14.5° ± 9.6° for anteversion. Mean intraoperative change of acetabular component was 1.9° ± 1.7° for inclination and 1.9° ± 1.9° for anteversion. The use number of the screw was an average of 1.46 (1 to 4). The intraoperative change of acetabular component anteversion correlated with number of screws (r = 0.381, p = 0.017), and vertical distance(r = 0.265, p = 0.05). The intraoperative change of acetabular component inclination also correlated with horizontal distance (r = 0.313, p = 0.02). Discussion. Many studies have shown that multiple bone screws are very helpful aids for cementless acetabular cup fixation. The multiple-screw fixation could have an effect on micromotion of the acetabular component. However, the change of acetabular alignment during inserting screws has not been clearly reported. The current study showed mean intraoperative change of acetabular component was 1.9° for inclination and 1.9° for anteversion. However, maximum change of acetabular component was 5° for inclination and 13° for anteversion. These findings suggest that the alignment of acetabular component could change during screw fixation, and the change might cause malalignment of the acetabular component, and could increase the risks of impingement, dislocation, and accelerated wear. The change of acetabular alignment correlated with number of screws and radiographycal measurements in this series. Therefore, bone quality and bone stock could affect stability of acetabular component. In conclusion, navigation can show potential to help quantify intraoperative acetabular component alignment change during screw fixation and potentially reduce the risk for malpostion of acetabular components

Objective. The use of all pedicle screw constructs for the management of spinal deformities has gained widespread popularity. However, the placement of pedicle screws in the deformed spine poses unique challenges for the spinal surgeon. The purpose of this study was to evaluate the complications and radiological outcomes of surgery in 124 consecutive patients with spinal deformity. These patients underwent correction of coronal and sagittal imbalance with segmental pedicle screw fixation only. Background. All pedicle screw constructs have been associated with improved correction in all three planes. In patients with severe deformity, such constructs can obviate the need for anterior surgeries, and the higher implant cost is offset by the avoidance of dual anterior and posterior approaches. Pedicle screw fixation enables enhanced correction of spinal deformities, but the technique is still not widely applied for thoracic deformities for fear of neurological complications. This is a retrospective study that was carried out on 124 patients who underwent segmental screw fixation for coronal and sagittal spinal deformities. The purpose of this study was to evaluate the complications and outcomes of this technique and also assess the evidence of enhanced correction. Material and Methods. A total of 124 consecutive patients subjected to pedicle screw fixation for spinal deformities were analysed after a minimum period of follow-up of two years. Etiologic diagnoses were idiopathic scoliosis in 32, neuromuscular scoliosis 48, Scheuermann's kyphosis in 28 and others 16. They were reviewed using the medical records and preoperative, intraoperative and postoperative radiographs. Computed tomography was performed when screw position was questionable. Deformity correction was determined on preoperative and postoperative radiographs. The positions of the screws were evaluated using intraoperative and postoperative radiographs. There were 51 male and 73 female patients with the mean age of 17.2 years (range, 10-25 years). The average cobb angle for scoliosis and kyphosis were 55°(range 45°-85°) and 72° (range 68°-100°) respectively. Results. A total of 2784 pedicle screws were inserted and 1488 screws were inserted in the thoracic spine (18 screws/patient). Screw-related neurological complications occurred in two patients 0.4%; these comprised a transient paraparesis and dural tear. Other complications comprised six intraoperative pedicle fractures, 12 screw loosening, four postoperative infections and one haemothorax. There were no significant screw-related neurological or visceral complications. The average correction was 78% for scoliosis and 51% for kyphosis. The mean estimated blood loss was 653 ml (range, 510-850), the mean operation time was 148 minutes (range, 120-220). Conclusion. We were able to demonstrate that application of pedicle screw construct is safe and advantageous in the management of spinal deformities. Significant correction has been achieved with a single stage posterior surgery in all groups. Scoliosis and kyphotic deformity corrections were 78% and 51% respectively; this is far superior to correction achieved with one stage surgery with other constructs. This study showed that improved derotation has decreased the need for thoracoplasty, thus eliminating its risk of associated morbidity. Superior control of the deformity obviated the need for an anterior approach in severe curves. Improved correction, lower morbidity and shorter hospitalisation has compensated for higher implant cost. We believe using all pedicle screw fixation is a relatively safe procedure and offers an excellent correction. This correction was maintained throughout the follow up period. Despite our safety record in thoracic pedicle screw placement, we believe this technique can be potentially dangerous in inexperienced hands, and requires a long learning curve. Therefore, a thorough anatomical knowledge of pedicle morphology, a detailed analysis of pre-operative imaging coupled with experience is essential to avoid complications. Ethics approval None. Interest Statement None

Background. pelvic fractures in elderly patients often result in poor prognosis due to immobilization associated complications. Thus, the target of the treatment in this patient group is early mobilization in order to reduce the risk of these complications. We report outcomes of 4 cases of pelvic fracture in elderly patients, who were treated with percutaneous screw fixation. Material and method. We examined medical records and images of 4 elderly patients between January 2012 and May 2012 in our center. Mean age of the patients was 88.8 years old (range 86–92 years). The causes of injury were motor vehicle accident in 3 patients, and a fall in 1 patient. Fracture types were ao type a in 1 patient, type b in 2 patients and type c in 1 patient. Mean injury severity score was 25 (10–57). We assessed functional status after the follow-up period using majeed. s. grading score for pelvic fractures. Result. No major complication including sever infection and deep vein thrombosis was observed during the follow-up period. Minor complication observed was screw loosening in 1 case, and screw prominence in another. Functional outcome by majeed. s. score were excellent in 1 case, and fair in 3 cases. The mean period between the operation and the first ride on the wheel chair was 3.5 (2–6) days. Conclusion. Early mobilization significantly affects the prognosis in multiple trauma patients. Percutaneous screw fixation may improve the prognosis in elderly patients with pelvic fracture

Lag screw fixation with plate osteosynthesis is the usual recommendation for oblique non-comminuted lateral malleolus fractures. Lag screw fixation may sometimes pose varying difficulties depending on the orientation of the fracture and in osteoporotic bones where the process may cause disintegration of the bone. The purpose of this study was to evaluate whether additional lag screw fixation with plate osteosynthesis offered any advantage over plate only fixation in non-comminuted oblique fractures of the lateral malleolus. A simple method of fixation was employed where the fracture was reduced and held temporarily with a K wire. After fixation with plate the K wire was removed. A total of 20 patients who had non-comminuted unstable oblique fractures of their lateral malleolus that had been surgically fixed plate only fixation were retrospectively evaluated. The patients were aged between 17 and 70 yrs. Evaluation of the success of fixation, complications, resultant mobility and patient satisfaction was based on information gathered from X-ray findings and clinic notes. These results were compared to an agematched group of 20 consecutive patients treated with lag screw fixation and plate osteosynthesis. There was no significant difference in the rate of or functional outcomes in either groups. Lag screw fixation offers no additional advantage when combined with plate synthesis of non-comminuted oblique lateral malleolus fractures

The treatment of undisplaced femoral neck fracture in the elderly population is still controversial. We analysed the outcome of cancellous screw fixation for undisplaced femoral neck fracture in patients over 70 years. Materials and methods. From 1998 to 2003, ninety-seven patients with undisplaced femoral neck fracture, aged over 70 and treated with cancellous screw fixation were retrospectively identified. Full clinical data was available for 79 of the 97 patients identified. All patients had in situ fracture fixation. Results. Of the 79 patients, M:F was 22:57, average age was 81.3 years. The average inpatient stay was 13.2 days. The mean follow-up was 12 months. 24 patients had Garden type I and 55 type II fractures. 26 (32.9%) patients did not return to their pre-morbid mobility status, 5 (6.3%) did not return to their preadmission dwelling (2 went to residential homes and 3 to nursing homes). We had documented radiographic details in 46 patients: 41 patients had a healed fracture on radiographs (89.1%), 5 patients had AVN, 4 patients had non-union and 1 patient had AVN with non-union. The radiographic failure rate was 22%. 15 patients had evidence of screw back out with healed fracture. 12 of the 46 complained of pain post-operatively of which 9 (19.6%) patients had re-operation; 6 (13%) underwent revision surgery and 3 (6.5%) required screw removal. 30-day mortality was 3.7%. 1-year mortality was 23.2% of which 16 died within the first 6 months (19.5%). Conclusion. This study shows that, in our unit, cancellous screw fixation of undisplaced femoral neck fractures in patients over the age 70 had a good outcome with a 20% re-operation rate and 22% radiographic failure rate. One third of the patients did not return to their preadmission mobility level/dwelling

Purpose of study. Unstable pelvic ring injuries usually occur in polytrauma patients and are associated with high mortality and morbidity. Percutaneous screw fixation of sacro-iliac joint dislocations, fracture-dislocations and sacral fractures is a well-recognised technique first described by Routt and is increasingly gaining popularity. This method is biomechanically comparable to open reduction and internal fixation with plates and screws but offers the advantages of minimally invasive surgical techniques. It is however a technically demanding procedure with reported complications including hardware failure, misplacement of screws, nerve injury and poor posterior reduction. The purpose of the study is to report clinical results of patients treated with closed reduction and percutaneous ilio-sacral screw fixation for unstable pelvic ring fractures by a single surgeon. Methods. A review of prospectively collected data was performed on all patients who had percutaneous sacro-iliac fixation between 2009 and 2012. Thirty five percutaneus sacro-iliac screws were inserted in 30 patients with a mean age of 25.6 years (range 17–62). Fracture types included 10 AO type B, and 20 AO type C. The mean follow-up period was 11.6 months (range 3–38). The complications assessed were screw misplacement, neurovascular complications, hardware breakage and loss of reduction. Results. All patients had a satisfactory initial reduction. One patient (2.8%) had misplacement of a screw with resultant temporary neurological fallout. One patient (2.8%) had screw misplacement without neurological fallout. Both of these patients initially had two screws inserted and the misplaced screws were removed and not reinserted. One patient (2.8%) had screw cut-out with loss of reduction. This screw was removed, open reduction peformed and the screw was re-inserted. Conclusion. The use of percutaneous sacro-iliac screws provides a safe and effective technique for the management of unstable posterior pelvic ring injuries. Our combined complication rate is comparable to published literature. NO DISCLOSURES

Prosthetic reconstruction of high-riding hips is technically demanding. Insufficient bony coverage and osteopenic bone stock frequently necessitate transacetabular screw fixation to augment primary stability of the metal shell. We sought to determine the validity of the previously reported quadrant system, and if needed, to define a specialized safe zone for augmentation of screw fixation to avoid vascular injuries in acetabular cup reconstruction for high-riding hips. Volumetric data from computed tomography enhancement scanning and CT angiography of eighteen hips (twelve patients) were obtained and input into a three-dimensional image-processing software. Bony and vascular structures were reconstructed three-dimensionally; we virtually reconstructed a cup in the original acetabulum and dynamically simulated transacetabular screw fixation. We mapped the hemispheric cup into several areas and, for each, measured the distance between the virtual screw and the blood vessel. We found that the rotating centers of the cups shifted more anterior-inferiorly in high-riding hips than those in ordinary cases, and thus the safe zone shifted as well. Screw fixation guided by the quadrant system frequently injured the obturator blood vessels in high-riding hips. We then defined a specialized safe zone for transacetabular screw fixation for high-riding hips. We conclude that the quadrant system can be misleading and of less value in guiding screw insertion to augment metal shells for high-riding hips. A new safe zone specific to high-riding hips should be used to guide transacetabular screw fixation in these cases

The screw fastening torque applied during bone fracture fixation has a decisive influence on subsequent bone healing. Insufficient screw tightness can result in device/construct instability; conversely, excessive torques risk damaging the bone causing premature fixation failure. This effect is even more prominent in osteoporotic bone, a condition associated annually with almost 9 million fractures worldwide. During fracture fixation, screw tightening torque is applied using subjective feel. This approach may not be optimal for patient”s recovery, increasing risk of fixation failure, particularly in osteoporotic bone, and potentially require revision surgical interventions. Besides bone density, various factors influence the performance of screw fixation. These factors include bone geometry, cortical thickness and time-dependant relaxation behaviour of the bone. If the influence of screw fastening torque on the bone and relationships between these factors was better understood, the surgical technique could be optimised to reduce the risk of complications. Within this study, we developed an axisymmetric finite element (FE) model of bone screw tightening incorporating viscoelastic behaviour of the cortical bone such as creep and stress relaxation. The model anticipated time-dependent behaviour of the bone for different bone thickness and density after a typical bone fixation screw had been inserted. The idealised model has been developed based on CT scans of bones with varying densities and inserted screws. The model was validated through a series of experiments involving bovine tibiae (4–5 months) to evaluate the evolution of surface strains with time (Ncorr v1.2). Stress distribution was assessed in photoelastic experiments using acrylic analogues. Relaxation tests have been performed in aqueous environment for up to 48 hours to ensure the relaxation would be complete. The creep behaviour (maximum principal strain) was compared against computational predictions. Our early simulations predicted relaxation strains on the surface of the bone to be 1.1% within 24 hours comparing favourably to 1.3% measured experimentally. Stress distribution patterns were in agreement with photoelastic results. Using experimentally derived viscoelastic properties, the model has the potential to predict creep and stress relaxation patterns after screw insertion with different fastening torques for bones with varying density and geometry. We aim to develop this into a planning tool providing guidance to surgeons for optimal tightening when using screw fixation, particularly in reduced quality bone