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

Abstract. Objectives. To evaluate the safety and efficacy of vertebroplasty with short segmented cement augmented pedicle screws fixation for severe osteoporotic vertebral compression fractures (OVCF) with posterior/anterior wall fractured 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% to 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. Vertebroplasty is viable option for restoring vertebral anterior column in patients who are considered as contraindications for vertebroplasty, like DGOU-4. It provides anterior support avoiding corpectomy, minimise blood loss and also duration of surgery. Addition of short segment fixation gives adequate support with less stress risers at the junctional area

Introduction. Acetabular fractures are a challenging problem. It has been published that outcome is dependent upon the type of fracture, the reduction of the fracture and concomitant injuries. The end-points of poor outcome include avascular necrosis of the femoral head, osteoarthritis. However, we lack definitive statistics and so counselling patients on prognosis could be improved. In order to achieve this, more outcome studies from tertiary referral centres are required. We present the first long term follow up from a large tertiary referral centre in Ireland. Methods. We identified all patients who were ten years following open reduction and internal fixation of an acetbular fracture in our centre. We invited all of these patients to attend the hospital for clinical and radiographic follow-up. As part of this, three scoring systems were completed for each patient; the Short-form 36 health survey (SF36), the Merle d'Aubigné score and the Short Musculoskeletal Functional Assessment (SMFA). Results. The data represents one year's activity at a new tertiary referral unit. We identified a total of 44 patients who were ten years following ORIF of acetabular fractures in our unit. 21 patients (48%) replied to written invitation and attended the hospital for clinical and radiographic follow-up. A further 7 patients were contacted by telephone and interviewed to gauge their rehabilitation. 3 patients had passed away. The remaining 13 patients were not contactable. Of those who attended in person for follow-up; 18 were male and 3 were female. The mean age at follow-up was 40.5 years (Range 27-60). In terms of fracture pattern epidemiology, 43% of patients sustained posterior column and wall fractures, 29% posterior wall, 14% posterior column alone, 9.5% transverse with posterior wall and 9.5% bicolumnar. 2 patients in the follow-up group had total hip replacements. Of the remaining patients the overall mean SF36 score was 78.8% (SD 16.4). The mean SMFA was 14.1% (SD 5). The mean Merle d'Aubigné score was 14.9 (SD 3.2) with 63% graded as good or excellent. Comparison of outcome between sub-groups according to fracture classification showed no significant difference. Traumatic sciatic nerve injury was sustained by four patients in the follow-up group and all patients continued to complain of ongoing weakness. Of the patients who were contacted via telephone, 2 had total hip replacements. The remaining 5 reported no significant problems with their hips and cited this as the reason for not attending follow-up. Conclusion. Overall the outcome of the patients was more favourable than expected. This was supported by the results of the clinical scoring systems. In some patients this also appeared to be despite poor radiographic findings. Our observations suggest that concomitant injuries, especially sciatic nerve injury have a profound negative influence on the patients' ability to fully rehabilitate. These data provide a valuable tool for the trauma surgeon in providing the patient with an educated prognosis

Introduction. The objective of this study was to compare the performance of the Explant Acetabular Cup Removal System (Zimmer), which has been the favored system for many surgeons during hip revision surgery, and the new EZout Powered Acetabular Revision System (Stryker). Methods. 54mm Stryker Trident® acetabular shells were inserted into the foam acetabula of 24 composite hemi-pelvises (Sawbones). The hemi-pelvises were mounted on a supporting apparatus enclosing three load cells. Strain gauges were placed on the hemipelvis, on the posterior and the anterior wall, and on the internal ischium in proximity to the acetabular fossa. A thermocouple was fixed onto the polar region of the acetabular component. One experienced orthopaedic surgeon and one resident performed mock revision surgery 6 times each per system. Results. Statistical analysis was conducted using Tukey's range test (HSD). The maximum force transferred to the implant was more than 4X lower with the EZout System regardless the surgeon experience (p=1.0E-08). Overall, recorded strains were lower for the EZout System with the higher decrease in strain (5X) observed at the posterior wall region(p=2E-08). The temperature at the interface was higher for the EZout System but never more than 37°C. Total removal time was on average reduced by a third with the EZout System (p=0.01). The calculated torque was lower for the EZout System. The amount of foam left on the cup after removal, which mimics the compromised bone, was 2.5X higher on average for the Explant System with most of the foam concentrated in the polar region. Lastly, it was observed that the polar region of each implant was reached by rotating the EZout System handpiece within a very narrow cylinder of space centered along the axis of the acetabular component compared to the Explant System, which required movement of the pivoting osteotomes within a large cone-shaped operating envelope. Discussion. Quantitatively, the EZout System required lower force, producing lower strains in the surrounding composite bone. Higher impact forces and associated increased strains may increase fracture risk. Qualitatively, the Explant System required a greater cone of movement than the EZout System requiring more space for the surgeon to leverage the handle of the tool. In addition, both surgeon and resident felt substantially greater exhaustion after using the Explant System vs. the EZout System. The resident compensated for the increased workload of the Explant with time, the experienced surgeon with force. The learning curve for both experienced surgeon and resident was also much shorter with the EZout System as shown by the close force values between the experienced surgeon and resident. Conclusion. Based on the results of this in vitro model, the EZout Powered Acetabular Removal System may be a reasonable alternative to manual removal techniques

Background. Acetabular fractures occur as a result of high-velocity trauma and are often associated with other life threatening injuries. Approximately one-third of these fractures are associated with dislocation of the femoral head but there are only few studies documenting the long term outcomes of this group of acetabular fracture. Methods. This was undertaken at the Royal Infirmary of Edinburgh which provides the definitive orthopaedic treatment for all major trauma including all acetabular fractures for the South East of Scotland. We retrospectively reviewed patients who sustained an acetabular fracture associated with a posterior hip dislocation from a prospectively gathered trauma database between 1990 to 2010. Patient characteristics, complications and the requirement for further surgery were recorded. Patient outcomes were measured using the Oxford Hip score and Short Form SF-12 health survey. Results. A total of 99 patients were treated over a 24 year period. The mean age was 41.3 years. The majority were male (75%). Road traffic accidents were the most common mechanism of injury (47%). The most common Letournal & Judet classification was a posterior wall fracture. Complications such as Sciatic Nerve Palsy was 12.1%, DVT 3%, Infection 5%, Heterotopic ossification 6.1%, Avascular necrosis at 11.1% and 19.2% went on to have a total hip replacement. The mean Oxford Score for Native hip was 34.7 and 31.8 for those who converted to hip replacement. SF12 Physical score was was 40.3 and 39 for the native hips and converted hips respectively. And the SF12 Mental score was 45.5 and 44.9 for the native hips and converted hips respectively. Conclusions. This is the first study to present the long term outcomes following an acetabular fracture dislocation. Our study suggests there is considerable disability in this group of patients and the requirement for subsequent THR has inferior patient reported outcomes. Level of Evidence. Cohort study, Level 2B

Summary Statement. There are no standardised methods for assessing the cement flow behaviour in vertebroplasty. We propose a novel methodology to help understand the interaction of cement properties on the underlying displacement of bone marrow by bone cement in porous media. Introduction. Concerns related to cement extravasation in vertebroplasty provide the motivation for the development of methodologies for assessing cements (novel and commercially available) and delivery systems. Reproducible and pathologically representative three-dimensional bone surrogates are used to understand the complex rheology underlying the two-phase flow in porous media. Patients & Methods. The bone surrogates were achieved by first developing CAD models then manufacturing the physical models through a suitable rapid prototyping technique. MicroCT 100 (Scanco Medical, Switzerland) was used to assess the variability in the model morphology (n=8). Contact angle measurements were performed on the material to compare the surface wettability to that of bone. The surrogates were filled with bone marrow substitute (Carboxymethyl cellulose 2.5 % in water, 0.4 Pa.s) then 5 ml of silicone oil (Dow Corning Corp. 200® Fluid, 60 Pa.s) was injected at a constant flow rate (3mL/min) using a syringe pump. The injection was radiographically monitored and the video sequences were captured. Experiments were repeated three times. The displacement of the syringe plunger and the force applied on the plunger were recorded. Image processing was performed on the video sequences to quantitatively describe the resulting flow patterns and calculate parameters including the time of leakage and the mean spreading distance. Results. The variability in the model morphology was very low with a strut thickness of 0.253 ± 0.010 mm and a pore spacing of 0.83 + 0.01 mm. The surface wettability was very similar between all materials with a contact angle around 65°. The measured displacement of the syringe plunger confirmed the flow rate to be constant at 3 ml/min. The peak injection pressure was 0.443 ± 0.013 MPa which is well below the reported clinical measurement of injection pressure during vertebroplasty. 1. Anterior oil leakage occurred at 34.6 ± 4.71 seconds. The oil never reached the posterior wall and the mean spreading distance at the end of the injection was 23.39 ± 1.11 mm. Discussion/Conclusion. These complex three-dimensional bone surrogates provide a clinically relevant representation of the in vivo situation in terms of geometry, porosity and permeability. They overcome limitations of previous models by being constant in terms of both porosity and geometry which is crucial to reduce the variability, render the experiments reproducible and shift the focus onto understanding the cement flow behaviour. The proposed methodology will help study cement-fluid interaction to get better representation of in vivo cement flow patterns and provide a tool for validating computational simulations. Funding was provided by the EU under the FP7 Marie Curie Action (PITN-GA-2009-238690-SPINEFX)