empty (N=5), iliac crest autograft (N=6), or PLGA/CaP biodegradable scaffold Tissue Regeneration Therapeutics Inc., ON, Canada) (N=7). Fluorescent markers were given at different times: calcein green (six weeks), xylenol orange (nine weeks), and tetracycline (11 and 14 weeks). Animals were sacrificed at 15 weeks and perfused with a barium compound. Radiography, Micro CT, and brightfield and fluorescent microscopy were used for analysis.
We conducted a systematic review and meta-analysis of randomised controlled trials comparing cross-linked with conventional polyethylene liners for total hip replacement in order to determine whether these liners reduce rates of wear, radiological evidence of osteolysis and the need for revision. The MEDLINE, EMBASE and COCHRANE databases were searched from their inception to May 2010 for all trials involving the use of cross-linked polyethylene in total hip replacement. Eligibility for inclusion in the review included the random allocation of treatments, the use of cross-linked and conventional polyethylene, and radiological wear as an outcome measure. The pooled mean differences were calculated for bedding-in, linear wear rate, three-dimensional linear wear rate, volumetric wear rate and total linear wear. Pooled risk ratios were calculated for radiological osteolysis and revision hip replacement. A search of the literature identified 194 potential studies, of which 12 met the inclusion criteria. All reported a significant reduction in radiological wear for cross-linked polyethylene. The pooled mean differences for linear rate of wear, three-dimensional linear rate of wear, volumetric wear rate and total linear wear were all significantly reduced for cross-linked polyethylene. The risk ratio for radiological osteolysis was 0.40 (95% confidence interval 0.27 to 0.58; I2 = 0%), favouring cross-linked polyethylene. The follow-up was not long enough to show a difference in the need for revision surgery.
We systematically reviewed the peer-reviewed literature to relate the survival of hybrid metal-on-metal hip resurfacing arthroplasty devices to a National Institute of Clinical Excellence (NICE) benchmark for choosing a primary total hip replacement, which is a survival rate of 90% at a follow-up of ten years. A total of 29 articles (10 621 resurfaced hips) met the inclusion criteria. The mean follow-up ranged from 0.6 to 10.5 years and the survival of the implant ranged from 84% to 100%. Of the 10 621 hips, 370 were revised (3.5%), with aseptic loosening as the most frequent mode of failure. None of the hip resurfacing arthroplasty implants used to date met the full ten-year NICE benchmark of survival. A total of 13 studies showed satisfactory survival compared with the three-year NICE benchmark.
The computed neck-shaft angle and the size of the femoral component were recorded in 100 consecutive hip resurfacings using imageless computer-navigation and compared with the angle measured before operation and with actual component implanted. The reliability of the registration was further analysed using ten cadaver femora. The mean absolute difference between the measured and navigated neck-shaft angle was 16.3° (0° to 52°). Navigation underestimated the measured neck-shaft angle in 38 patients and the correct implant size in 11. Registration of the cadaver femora tended to overestimate the correct implant size and provided a low level of repeatability in computing the neck-shaft angle. Prudent pre-operative planning is advisable for use in conjunction with imageless navigation since misleading information may be registered intraoperatively, which could lead to inappropriate sizing and positioning of the femoral component in hip resurfacing.
Femur fractures are a complication of hip arthroplasty. When the stem is well fixed, fracture fixation is the preferred treatment option. Numerous fixation methods have been advocated, using plates and/or allograft struts. The study was conducted to determine the biomechanical characteristics of three constructs currently used for fixation of these fractures. Vancouver type B1 periprosthetic femur fractures were created distal to a cemented hip stem implanted in third generation composite femurs. The fractures were fixed with one of three constructs: 1- A non-locking plate and allograft strut (NLP-A) 2- A locking plate and allograft strut (LP-A) 3- A locking plate alone. (LP) The struts were held in place with cables. There were five specimens in each group. Following fixation, the constructs underwent sinusoidal cyclic loading from 200 to 1200 N for 100000 cycles. Stiffness of the constructs was determined in bending, torsion and axial compression before and after cyclic loading. Axial load to failure was also determined. Overall, cyclic loading had little effect on the mechanical properties of these constructs. The two constructs with allografts were significantly stiffer in coronal plane bending than the construct consisting of only a locking plate. There were no significant differences in axial or torsional stiffness between the constructs. Load to failure of the NLP-A (4095 N) and LP-A (4007 N) constructs was significantly greater than the LP construct (3398 N) (p=0.023 and p=0.044 respectively). All three constructs tested retained their mechanical characteristics following 100000 cycles of loading. Our initial concerns that the cables holding the allograft strut would loosen appear unfounded. Allograft strut-plate constructs are stiffer in bending and have a higher load to failure than a stand-alone locking plate. When an allograft plate construct is chosen, locking screws provide no mechanical advantage in this experimental model.
Early fracture stabilization has been shown to reduce morbidity and mortality in the patient who is multiply injured. Controversy exists in terms of managing multiple trauma patients who sustain thoracic injuries along with femoral shaft fractures. The purpose of the present study was to determine whether the presence and treatment of femoral shaft fractures increases morbidity in patients with pulmonary contusions and to determine the effect of patient and surgical factors on outcome. Patients that suffered chest injuries between January 1987 and April 2006 were identified from the prospectively collected trauma databases at two hospitals. Patient records were reviewed to verify all data. The diagnosis of pulmonary contusion was confirmed with radiologic or post-mortem investigations. All relevant patient and surgical data was collected. Exclusion criteria included severely injured patients (head/abdomen AIS>
3), age sixty years, death twenty-four hours after injuries occurred. A total of 1190 patients with confirmed pulmonary contusions met inclusion criteria; there were 113 femoral shaft fractures (five bilateral). Patients in both the isolated pulmonary contusion and pulmonary contusion with femoral fracture had similar injury severity scores (ISS) and demographic information. Fractures were reduced with intramedullary nailing in 88% of cases. Mean age was thirty-five years. There were significantly more incidences of fat embolism syndrome and acute lung injury (ALI) in patients with femoral factures (twenty-four hours following the injury had significantly greater risk of developing ARDS (p<
0.05). The presence of femoral shaft fractures in patients with pulmonary contusions increases the duration of admittance to hospital and can lead to higher rates of fat embolism syndrome and ALI, however it does not appear to impact overall mortality or contribute to the development of other common respiratory complications. Early reduction of shaft fractures is encouraged to further decrease complications.
Fat embolism syndrome (FES) is a potentially lethal condition commonly seen in poly-traumatised patients, particularly those with multiple long-bone fractures. Treatment has centered around supportive care and early fracture fixation. Several clinical small trials have suggested corticosteroids benefit patients with FES but its use remains controversial. Our objective was to determine the effect of corticosteroids in preventing FES in patients with multiple long-bone fractures. We conducted a meta-analysis of randomised trials, searching computerised databases for published studies from 1966–2006. Additionally, we performed hand searches of major orthopaedic journals, meeting proceedings, and texts. Our primary outcome was the rate of FES. Secondary outcomes included presence of hypoxia, petechiae, mortality, infection, and delayed union. Of the one hundred and four studies identified, nine were potentially eligible, and only seven met all our eligibility criteria. From our pooled analysis of three hundred and eighty-nine patients, we found that corticosteroids reduced the risk of FES by 78% (95%CI: 43–92%, heterogeneity p-value=0.62, I2=10%) and that only eight patients needed to be treated (NNT=7.5) to prevent one case of FES (95%CI: five to thirteen patients). We did not find any significant differences in the rates of mortality, infection, or delayed union. The current evidence suggests that the use of corticosteroids is beneficial in the prevention of fat embolism syndrome in patients with multiple long-bone fractures. The use of corticosteroids does not appear to significantly increase the risk of complications although a confirmatory large randomised trial is needed.
We sought to establish whether fibroblasts transfected ex vivo could be delivered via gelfoam impregnated with a solution of transfected cells to achieve local transgene expression in a fracture site. A 10 millimeter segmental bone defect was created after 12 mm periosteal excision and plated in the middle one third of each rabbit tibia. Dermal tissues were obtained and fibroblasts were cultured with DMEM. Fibroblasts were labeled with CMTMR and 5x106 labeled fibroblasts in 1ml PBS with 1x1 cm? Impregnated gelfoam was placed into the fracture gap (n=2). Twenty four hours after cell injection, the rabbits were killed and specimens were harvested from the fractured leg. Using SuperFect (Qiagen Inc), the primary fibroblasts were transfected with pcDNA-VEGF which was generated with the full length coding sequence of the human VEGF gene. A convenient reporter gene, Efficiency Green Fluorescent Protein (EGFP), was used for monitoring transfection of VEGF by fluorescence intensity. Experimental rabbits received 5.0 X 106 VEGF transfected cells in 1 ml PBS via gelfoam at the fracture sites. The animals were sacrificed at seven days (n=4), fourteen days (n=4) and twenty-one days (n=4) post surgery and the fracture site specimens were collected for analysis. The fluorescently labeled cells with CMTMR were found at the fracture site and surrounding tissues. It was demonstrated that the labeled cells were delivered into the fracture gap, bone marrow and muscle surrounding a segmental defect in the rabbit. In the VEGF group, visualised VEGF immunostaining (brown) was shown in the fracture site around the Gelfoam; as well VEGF was distributed at sites of endochondral ossification. Visible bone formation was shown: VEGF promoted new bone formation by VonKossa staining (dark) and produced numerous vessels by CD31 positive staining (brownish black). The VEGF protein was detected in and around the fracture by ELISA. This data encourages the further development of genetic approaches using cell based VEGF gene transfer without viral vectors to promote fracture healing.