Aims

Prior to the availability of vaccines, mortality for hip fracture patients with concomitant COVID-19 infection was three times higher than pre-pandemic rates. The primary aim of this study was to determine the 30-day mortality rate of hip fracture patients in the post-vaccine era.

Introduction. Anterior tibial translation (ATT) is assessed in the acutely injured knee to investigate for ligamentous injury and rotational laxity. Specifically, there is a growing recognition of the significance of anterior medial rotary laxity (AMRI) as a crucial element in assessing knee stability. Anterior cruciate ligament (ACL) injuries are often accompanied with medial collateral ligament (MCL) damage. It has been suggested that Deep MCL (dMCL) fibres are a primary restraint in rotational displacement. This research aims to quantify the difference in rotational laxity of patients with ACL and MCL injuries to deem if the Feagin-Thomas test can robustly capture metrics of AMRI. 2. Methods. AMRI was assessed using the Feagin-Thomas test in 7 isolated ACL (iACL) injured participants, 3 combined ACL and superficial fibre MCL (sMCL) injuries, 5 combined ACL and deep fibre MCL injuries, and 21 healthy controls. Displacement values were recorded using an optical motion capture (OMC) system and bespoke processing pipeline which map and model the knee's anterior displacement values relative to the medial compartment. Since absolute values (mm) of rotational laxity vary dependant on the person, values were recorded as a proportion of the rotational laxity obtained from the subject's contralateral leg. Values were compared between each patient group using an ANOVA test and Tukey's honesty significant difference post hoc test. 3. Results. The healthy control group had a median proportion of 0.97 (3SF), whilst the iACL was 1.12 (3SF), a 12% increase in rotational laxity in the injured leg. The sMCL group yielded a result of 1.64 (3SF), a 64% increase in rotational laxity in the injured leg; finally, dMCL resulted in a proportion of rotational laxity of 1.90 (3SF), a 90% increase in rotational laxity [table 1]. Whilst all groups showed differences in the increase of rotational laxity, dMCL was significantly different from the healthy control group (P value 0.0041). 4. Conclusion. ACL injuries with MCL involvement led to an increase in anterior medial rotary laxity and this is more evident in patients where deep MCL fibres are involved. The Feagin-Thomas test appears to be sensitive in detecting differences in AMRI and should be considered when performing comprehensive clinical knee examination. For any figures or tables, please contact authors directly

Objectives. External fixators are the traditional fixation method of choice for contaminated open fractures. However, patient acceptance is low due to the high profile and therefore physical burden of the constructs. An externalised locking compression plate is a low profile alternative. However, the biomechanical differences have not been assessed. The objective of this study was to evaluate the axial and torsional stiffness of the externalised titanium locking compression plate (ET-LCP), the externalised stainless steel locking compression plate (ESS-LCP) and the unilateral external fixator (UEF). Methods. A fracture gap model was created to simulate comminuted mid-shaft tibia fractures using synthetic composite bones. Fifteen constructs were stabilised with ET-LCP, ESS-LCP or UEF (five constructs each). The constructs were loaded under both axial and torsional directions to determine construct stiffness. Results. The mean axial stiffness was very similar for UEF (528 N/mm) and ESS-LCP (525 N/mm), while it was slightly lower for ET-LCP (469 N/mm). One-way analysis of variance (ANOVA) testing in all three groups demonstrated no significant difference (F(2,12) = 2.057, p = 0.171). There was a significant difference in mean torsional stiffness between the UEF (0.512 Nm/degree), the ESS-LCP (0.686 Nm/degree) and the ET-LCP (0.639 Nm/degree), as determined by one-way ANOVA (F(2,12) = 6.204, p = 0.014). A Tukey post hoc test revealed that the torsional stiffness of the ESS-LCP was statistically higher than that of the UEF by 0.174 Nm/degree (p = 0.013). No catastrophic failures were observed. Conclusion. Using the LCP as an external fixator may provide a viable and attractive alternative to the traditional UEF as its lower profile makes it more acceptable to patients, while not compromising on axial and torsional stiffness. Cite this article: B. F. H. Ang, J. Y. Chen, A. K. S. Yew, S. K. Chua, S. M. Chou, S. L. Chia, J. S. B. Koh, T. S. Howe. Externalised locking compression plate as an alternative to the unilateral external fixator: a biomechanical comparative study of axial and torsional stiffness. Bone Joint Res 2017;6:216–223. DOI: 10.1302/2046-3758.64.2000470

An increased prevalence of osteoarthritis (OA) in post-menopausal women has led to the suggestion that hormonal factors may play a role in the pathogenesis. This study aims to examine if undergoing a hysterectomy, both with retention and removal of ovaries, predisposes women to OA and secondly if the development is influenced by hormone replacement therapy (HRT). Statistical shape modelling (SSM) is a method of image analysis allowing for detection of subtle shape variation described by landmark points. Through the generation of linearly independent modes of variation, each image can be described in terms of numerical scores. 149 radiographs from female participants of the Osteoarthritis Initiative (OAI) were examined to compare hip morphology in those who had undergone hysterectomies compared to controls. No differences were observed in BMI, age, height or weight between groups. ANOVA and Games-Howell post-hoc analysis showed that modes 3 and 5 were statistically significant. Lower mode 3 scores were associated with hysterectomy (p=0.019), with narrowing of the femoral neck and increased acetabular coverage. Lower mode 5 scores were associated with hysterectomy and oophorectomy (p=0.049), displaying reduced coverage of the femoral head, superolateral migration of the femoral head and larger greater trochanter. No associations were observed between HRT use and OA. The subtle morphologic features of hip OA present in only hysterectomised women suggests undergoing a hysterectomy may be a predisposing factor and a clinical consideration. The use of HRT was not observed to influence the development of OA and thus cannot be suggested as a protective measure

A 7-day randomised controlled pre-clinical trial utilising an existing extremity war wound model compared the efficacy of saline soaked gauze to commercially available dressings. The Flexor Carpi Ulnaris of anaesthetised rabbits was exposed to high-energy trauma using a computer-controlled jig and inoculated with 10. 6. Staphylococcus aureus 3 hours prior to application of dressing. Quantitative microbiological assessment demonstrated reduced bacterial counts in INADINE (Iodine) and ACTICOAT (Nanocrystalline Silver) groups and an increase in ACTIVON TULLE (Manuka Honey) group (2-way ANOVA p<0.05). Clinical observations were made throughout the study. Haematology and plasma cytokines were analysed at intervals. Post-mortem histopathology included subjective semi-quantitative assessment of pathology severity using light microscopy to grade muscle injury and lymph node activation. Tissue samples were also examined using scanning electron microscopy (SEM). There were no bacteraemias, abscesses, purulent discharge or evidence of contralateral axillary lymph node activation. There were no significant differences in animal behaviour, weight change, maximum body temperature or white blood cell count elevation nor in pathology severity in muscle or lymph nodes (Kruskal-Wallis). There was no evidence of bacterial penetration or biofilm formation on SEM. Interleukin-4 and Tumour Necrosis Factor α levels were significantly higher in the ACTIVON TULLE group (1-way ANOVA p<0.05). This time-limited study demonstrated a statistically significant reduction in Staphylococcus aureus counts in wounds dressed with INADINE and ACTICOAT and an increase in wounds dressed with ACTIVON TULLE. There was no evidence that any of these dressings cause harm but nor have we established any definite clinical advantage associated with the use of the dressings tested in this study

Aim. To investigate the biomechanical behaviours of the TL-Hex & Taylor Spatial Frame (TSF) Hexapod external fixators, with comparison to traditional ring-fixator constructs. Methods. Standardised four-ring TL-Hex and TSF constructs, as well as matched ilizarov threaded-rod constructs for each set of components, were tested alone and mounted with an acrylic bone model with simulated fracture gap using fine-wires. Load-deformation properties for each construct and mode of loading were calculated and analysed statistically using ANOVA. Results and Conclusions. Under axial loading the Ilizarov construct utilising TL-Hex components demonstrated greatest rigidity followed by the TL-Hex Ilizarov using TSF components (p<0.01). Under torsional loading both hexapod frames were seen to be significantly more rigid than the Ilizarov (p<0.01), with the TSF demonstrating greater rigidity than the TL-Hex. Under cantilever bending loads the difference in rigidity seen across all constructs was less marked. When loaded with the bone model both hexapods demonstrated reduced axial rigidity as compared to Ilizarov constructs, but without any appreciable difference in translational shear strain. Under cantilever bending the Ilizarov construct using TL-Hex components p<0.01) demonstrated less translational shear strain than the TSF and TSF using Ilizarov components. In conclusion, both hexapod designs were less rigid axially, but more so under bending and torsional loads, than their Ilizarov construct counterparts, producing greater overall planar shear strain, largely due to the observed “toe-in” laxity. Overall, the TL-Hex was seen to be more rigid that the TSF under bending loads although the difference in shear strain at the fracture site was not significantly different

Purpose. Tibia plateau fractures are severe knee injuries which have a great impact on the patients' lives, but in what extend is not clear yet in the literature. The purpose of this study was to investigate the gait alternations after treatment of patients who had severe tibia plateau fractures which were treated with circular ilizarov frame. Materials & Methods. We have evaluated the gait pattern of patients who were treated with circular Ilizarov frame after severe tibia plateau fractures (Schatzker IV-VI) in our department. The gait was tested by using a force plate in a walking platform. Ground Reaction Forces (GRF) data were collected during level walking at self-selected speeds. The patients performed two walking tasks for each limb and the collected data were averaged for each limb. Demographic, clinical, radiological and quality of life questionnaire (SF-12) data were also collected. Results. We have analysed the gait through the GRF of fifteen patients (aged 50.8 ±17.3 years), who had undergone treatment with circular Ilizarov frame following severe tibia plateau fractures (Schatzker IV-VI). Nine were male and six were female. The tests were performed at an average of 13.2 months after the initial treatment. SF-12 Mental scores have returned to normal (mean 54.6 ±12.3) but physical scores remained impaired (mean 40.6 ±10.8). A one-way repeated measures ANOVA was conducted to compare the GRFs and gait timing data of the affected limb with the normal one. Single limb support interval was significantly reduced to the affected limb (p=0.001) and terminal stance phase was prolonged for the normal limb (p=0.035). During this phase of the gait circle the knee is on its maximum flexion and the quadriceps contracts to bring the femur above the tibia. It seems that these patients during the gait circle reduce the flexion of their affected knee to make their single stance shorter. To the normal limb the patients manage to reduce more the GRFs during the mid-stance phase (F2 force), this difference do not reach significance, but illuminates the tendency of reduced knee flexion in that phase. The rest of the GRF and gait timing data did not had significant differences. Conclusions. One year after severe tibia plateau fracture treated with circular ilizarov frame the patients manage to return to almost normal gait pattern. Reduce single limb stance and terminal stance phase to the affected knee can be explained by the tendency of not flexing their deficient knee as much during that gait phase

The use of external fixation in the management of long bone fractures has long been recognised. The aim of this study was to compare 3 differing constructs of Hoffman-2 and Hoffman-3 External Fixator systems to assess which potentially withstood the greatest load. Three different constructs (2, 3 and 4-bar) of Hoffman 2 and 3 External Fixation systems were tested. A UHMWPE tube was utilised as a bone substitute to construct a biomechanically reproducible model which could be tested on an MTS testing jig. Each construct was loaded to 3, 5, 8, 12 and 15mm of displacement at the fracture gap. Each construct was cyclically loaded 200 times for each test and repeated 5 times. The results demonstrate that the Hoffman-3 configurations withstood a load of at least twice that of the Hoffman 2 configurations across all displacements. Using a 2-way ANOVA test at all displacements the 2-bar configuration withstood greater load than the 3 bar (P<0.0001). With Hoffman 2 the 2-bar configuration withstood a greater load than the 4 bar diamond configuration. These results demonstrate that Hoffman-3 External Fixation Device has a greater axial loading capacity than its Hoffman-2 predecessor

Aims

Minimally invasive fixation of pelvic fragility fractures is recommended to reduce pain and allow early mobilization. The purpose of this study was to evaluate the outcome of two different stabilization techniques in bilateral fragility fractures of the sacrum (BFFS).

Hip fractures are common in the elderly. These people often had a history of multiple falls, and previous fractures. Fear of falling (FOF) have being reported in the follow-up of hip fractures. Aims. To evaluate the FOF in patients just after hip fracture and before surgical treatment. Material and methods. Prospective study of patients admitted in our hospital with hip fracture (subcapital, trochanteric and subtrochanteric). All patients were evaluated using the FES-I score for FOF before surgical treatment. Clinical and social data, previous history of falls, and fractures were recorded. Exclusion criteria were a score below 8 on the Minimental test on admission and previous hip fracture. Stadistical analysis were peformed using ANOVA, chi square and contingency tables. Results. During the 7 months that lasted this work 144 hip fracture were admitted to our hospital. Only 40 had a Minimental score of 8 or more, mean age was 82 years old, they were 33 female and 7 male, 18% of them were living at home, alone, 82% with their partners or other family members, 40% had no history of previous falls, 10 falls in the last year was reported by one patient. No or little FOF were reported by 52% of patients, while 48% had fear or too much fear. We have found a statistical significant relationship between FOF and patient age (p<0,001), fracture type (p<0,05), and previous history of falls (p<0,05). Conclusion. FOF prior to hip fracture is strongly related to of age, previous falls and fracture type

Orthopedic surgery is one of the most blood-consuming surgeries. Currently there has been a radical change in transfusion policies, developing a series of therapeutic measures essentially created to minimize the use of allogeneic blood. On the one hand, the safety of our patients must be even more our main objective. On the other hand, our economic resources are more restricted and therefore we must evaluate our surgical techniques and proceedings in order to be safer and more cost-effective. The aim of this study is to report our results of the blood lost, the percentage of blood loss, the necessity of transfussions and how many blood pakages are needed. From a sample of 2400 total knee arthroplasties proceedings, we analyze some surgical proceedings such as lligament balance, patelar traking, artrotomy, ischemia, femoro-tibial axis and type of arthroplasty. We also examine the total blood lost and the percentage of total blood loss after 4 hours, after 24hours and after 48 hour of the total knee arthoplasty surgery. We made a statistical analysis with t-test or anova test when it was necesassary. The outcome of our investigation show that the blood loss when the ischemia is less than 50 minutes is 1470 cc and 1603 cc when is more than 50 minuntes (p<0.05). If we use the medial arthrotomy, the total bleeding is 1563cc, but with subvastus arthrotomy is 1294cc (p<0.05). If we use a primary rotational total knee arthroplasty the bleeding is 953cc, but if we use a PS or PCR the bleeding is 874cc (p<0.05). As a conclusion we should know that our patients have more blood loss when the ischemia is more than fifty minutes, the bleeding is higher when we make a medial arthrotomy and when we use a rotational knee primary arthroplasty

Aim. The aim of this prospective comparative study was to evaluate the serum levels of different cytokines in patients underwent total knee replacement (TKR) and received allogeneic blood transfusion, post-operative auto-transfusion or not transfused. Material and Methods. This was a prospective non-randomized comparative study in 248 patients underwent TKR. Patient's demographic and clinical data including age, gender, body mass index (BMI), preoperative Hb value, complications were documented. The serum levels of IL-1b, IL-6, IL-8, IL-10, and TNF were measure pre-operatively, the 1st, 2nd, 3rd and 5th post-operative day. Patients were categorized in three groups; in Group 0 patients received no blood transfusion, in Group 1 patients received post-operative auto-transfusion and in Group 2 allogeneic blood transfusion was applied. Statistical analysis of the results was performed using repeated measures ANOVA. Results. Significant changes were observed in cytokines levels in Groups 1 and 2. In Group 1 (auto-transfusion) the levels of all cytokines significantly increased the 1st postoperative day, remaining above the pre-operative levels even the 5th post-operative day. In Group 2 (allogenic transfusion), although the levels of IL-6, IL-8 and IL-10 were also significantly increased the 1st postoperative day, they gradually returned to the per-operative levels by the 5th post-operative day. In Group 0 (no transfusion) the only significant increase was observed in IL-6 between pre-operative and 1st and 3rd day values. Furthermore, the area under the curve (AUC) of IL-1b, IL-6, IL-8 and IL-10 levels in Group 1 and AUC of IL-6, IL-8 and IL-10 levels in Group 2, were significantly higher compared to Group 0. There was no significant difference in post-operative patient's complications. Conclusion. According to the results of this study significant elevation of cytokine values were observed during the first five post-operative days in patients received blood transfusion after TKR. These changes were more pronounced in the auto-transfusion group

Introduction. The pathophysiology of high failure rates following rotator cuff tendon repairs, particularly massive tears, is not fully understood. Collagen structural changes have been shown to alter tendon thermal and mechanical properties. Thermal changes in small biopsies, detected by differential scanning calorimetry (DSC) can help to quantify collagen structural differences in torn rotator cuff tendons. This study aimed to form a quantitative rather than qualitative assessment, of whether differences in collagen structure and integrity existed between small biopsies of normal, small and massive rotator cuff tears using DSC. Methods. Thermal properties were measured for 27 human biopsies taken intra-operatively from normal, small, and massive rotator cuff tendon tears. 3 samples were taken from each patient and subjected to a modulated temperature ramp between 20–80°C at a rate of 2°C per minute with 0.318°C amplitude. The melting temperature (TM) is proposed to represent amide-amide hydrogen bond breakage and resulting protein backbone mobility. Denaturing temperature (TD) reportedly corresponds to the temperature at which the proteins fall out of solution. Denaturation enthalpy (H) should correlate with the amount of triple helical structure. Based upon a pre-study power calculation, this study had 90% power to detect a 10% difference in melting and denaturation temperature between groups with alpha=0.05. 1 specimen per patients was also frozen and cryosectioned and polarised light microscopy was used for quantitative validation. The effect of tear size on heat related parameters were performed using a one-way ANOVA test. A student's unpaired t-test was used to search for differences between individual groups (small tears, massive tears and normal tendons). Results. Small and massive rotator cuff tears had significantly higher melting temperature (TM), and denaturation enthalpy (H) compared to controls. The denaturing temperature (TD) was higher in the massive tears only compared to normal tears. No difference was detected between small and massive tears. Histology of massive tendon tears confirmed greater collagen structural disruption compared to small tears and controls. Conclusion. These novel findings suggest greater quantifiable collagen structural disruption in rotator cuff tears, compared to controls. A decrease in important thermal properties of torn tendons suggests that the material is intrinsically less stable. It is likely that torn tendons cannot withstand changes in temperature or stress as well as a perfect material could, particularly for massive tears which are more amenable to denaturation. This study offers insight into possible mechanisms for, or adaptation to, failure in tears and reduced strength

Introduction. Proper rotational alignment of the tibial component in total knee arthroplasty (TKA) could be achieved using several techniques. The self adjustment methodology allows the alignment of the tibial component under the femoral component after several flexion-extension movements. Our hypothesis was that this technique allowed a posterior tibial component alignment parallel to the femoral component posterior bicondylar axis. The aim of this study was to access this hypothesis using a post-operative CT-scan study. Materials and Methods. This prospective CT-scan study involved 94 TKA. Theses TKA were divided in two groups: group1: 50 knees with a pre-operative genu varum deformity (mean HKA: 172.2°), operated using a medial parapatellar approach, and group 2: 44 knees with a preoperative valgus deformity (mean HKA: 188.7°), operated using a lateral parapatellar approach. Four measures were done on each post-operative CT-scan: angle between anatomical transepicondylar axis and femoral component posterior bicondylar axis (FCPCA), angle between FCPCA and tibial component marginal posterior axis, angle between tibial component marginal posterior axis and bony tibial plateau marginal posterior axis (BTPMPA), angle between transepicondylar axis and tibial component marginal posterior axis. Each measure was repeated, after one month by the same independent observer. Statistical evaluation used non-parametric Wilcoxon–Mann–Whitney test to compare each group of measures, and intraobserver reproducibility was assessed using ANOVA test, with an error rate of 5%. Results. Intraobserver measurements were reproducible. Mean FCPCA was to 3,1° (SD:1,91) in group 1 and 4,7° (DS: 2,96) in group 2. Tibial component was positioned in external rotation in both groups, in relation to FCPCA: (group 1: mean angle: 0,7° (SD:4,45), group 2: mean angle: 0,9° (SD:4,53)) and in relation to BTPMPA: (group1: mean angle: 6,1° (SD: 5,85); group2: mean angle: 12,5° (SD: 8,6)). There was no statistical difference between these two groups. Tibial component was positioned in internal rotation in relation to anatomical transepicondylar axis: (Group1: mean angle: 1,9° (SD: 4,93); group 2: mean angle: 3° (SD: 4.38)). Discussion. By using the self adjustment technique, tibial component is aligned parallel to the femoral component regardless of the initial frontal deformity and the surgical approach. However, there was a difference in tibial component axis and BTPMPA, between the two groups. This difference should be explained by the difference in morphology of the tibial plateau bone in knee with genu valgum deformity. The self adjustment technique is a reliable method to obtain a proper rotational alignment of the tibial component in TKA

Introduction. Osteoporosis (OP), osteoarthrosis (OA), and rheumatoid arthritis (RA) are the most common age-related degenerative bone diseases, and major public health problems in terms of enormous amount of economic cost. RA is considered as a major cause of secondary osteoporosis. At late stage, OP often leads to skeletal fractures, and OA and RA result in severe joint disability. Over the last a few decades, much significant research on the properties has been carried out on these diseases, however, a detailed comparison of the microarchitecture of cancellous bones of these diseases is not available. In this study, we investigated three-dimensional (3-D) microarchitectural properties of OP, OA and RA cancellous bone. We hypothesized that there were significant differences in microarchitecture among OP, OA and RA bone tissues that might lead to different bone quality. Materials and Method. Twenty OP, fifty OA, and twelve RA femur heads were harvested from patients undergone total hip replacement surgery. Cubic cancellous bone samples (8∗8∗8 mm3) were prepared and scanned with a high resolution microtomographic system (vivaCT 40, Scanco Medical AG., Brüttisellen, Switzerland). Then micro-CT images were segmented using individual thresholds to obtain accurate 3-D data sets. Detailed microarchitectural properties were evaluated based on novel unbiased, model-free 3-D methods. For statistical analysis, one-way ANOVA was used, and a p<0.05 was considered significant. Results. Significant differences in the microarchitecture of cancellous bone were observed among the OP, OA and RA groups. Compared with the other groups, OP cancellous bone had lowest density, thinner, typical rod-like structure and less connectivity (all p<0.01). Interestingly, there were no significant differences in the microarchitectural properties measured between the OA and RA cancellous bones. Both OA and RA cancellous bones had significant higher bone volume fraction and were thicker, typical plate-like structure compared with the OP group (all p<0.01), even though there was clearly bone erosion observed in RA cancellous bone. Discussion. Quantification of the alterations in bone properties and quality will help to gain more insights into the pathogenesis of degenerative bone diseases and to target and develop novel approaches for the intervention and treatment, and for the design, fixation and durability of total joint prosthesis. Our study demonstrated that there were significant differences in the microarchitecture of the OP, OA and RA femur head cancellous bone. The OA and RA cancellous bone had similar bone density and microarchitecture despite apparent bone erosion in the RA cancellous bone. These results from femur head did not support the traditional notion that RA and OP had similar low bone density. Thus, whether femur head bone tissues from these diseases have similar bone collagen, mineral and mechanical properties, more importantly bone quality, should be clarified in the future

The osteointegration of a new three-dimensional reticular titanium material, Trabecular Titanium™, was assessed using a bilateral cancellous (distal femur, proximal tibia) and cortical (tibia diaphysis) bone drill hole model in 18 sheep. TT is a novel Ti6Al4V material characterized by a high open porosity and composed of multi-planar regular hexagonal cells. Two 5.0 mm diameter, 12 mm long cylinders (TT1 & TT2) of two different porosities (TT1:650 μm, TT2:1250 μm) were tested and compared to two solid predicate 5.0 mm diameter, 12 mm long Ti cylinders (PT1 & PT2) coated with porous Ti (PT1: vacuum-plasma spray coating; PT2: inert-gas shielding arc spray coating). Each implant type was surgically implanted at 4 separate locations in each sheep (16 implants per sheep). Three timepoints of 4, 16 and 52 weeks (n=6 sheep per timepoint) were used. Bone-implant interface was analyzed ex vivo by the determination of: 1) the shear strength (SS) measured during a push out test, 2) the percentage of bone in-growth (%B) using histomorphometry, 3) the bone apposition rate using fluorochrome labelling analysis and 4) the bone-implant contact using backscattered scanning electron microscopy (SEM). An ANOVA with a Bonferroni Post hoc test were used to detect differences between tested and predicate implants. P values 0.05 were considered significant. At 4 weeks, 5 out of the 6 TT1 could be pushed out of the cortical bone (COB) samples. The remaining TT1 collapsed during testing. All TT1 could be pushed of the cancellous bone (CAB) samples. Four out of the 6 TT2 could be pushed out of CAB and of the COB samples. At 16 and 52 weeks, only one TT1 and one TT2 could be pushed out of the bone samples, the remaining implants collapsed during testing. All the PTs were successfully pushed out at all timepoints. The mean %B of PT1 and PT2 did not significantly increase over time. For both materials, the mean %B ranged between 1.7% and 4.4% at 4 weeks and between 5.7% and 6.5% at 52 weeks. The mean %B of TT1 significantly increased over time in both COB (10.2% at 4 weeks, 46.2% at 16 weeks, 50.5% at 52 weeks) and CAB (5.8%, 23.9%, 24.3%). Similarly, the mean %B of TT2 significantly increased over time in both COB (7.8%, 48.6%, 65%) and CAB (4.5%, 24.1%, 38.6%). Bone apposition rates for the TT implants remained superior to 2 μm/day for the entire duration of the study. SEM showed an intimate bone-implant contact for all implant types at all timepoints. At 16 and 52 weeks, histomorphometry revealed an extensive osteointegration of the TT specimens. Bone-implant interface strength was so high for the TT implants that they could not be pushed out of the bone samples. The results of this study would indicate that the TT implants provide a good scaffold for bone in-growth

Introduction. The combined incubation of a composite scaffold with bone marrow stromal cells in a perfusion bioreactor could make up a novel hybrid graft material with optimal properties for early fixation of implant to bone. The aim of this study was to create a bioreactor activated graft (BAG) material, which could induce early implant fixation similar to that of allograft. Two porous scaffold materials incubated with cells in a perfusion bioreactor were tested in this study. Methods and Materials. Two groups of 8 skeletally mature female sheep were anaesthetized before aspiration of bone marrow from the iliac crest. For both groups, mononuclear cells were isolated, and injected into a perfusion bioreactor (Millenium Biologix AG, Switzerland). Scaffold granules Ø∼900–1500 μm, ∼88% porosity) in group 1, consisted of hydroxyapatite (HA, 70%) with -tricalcium-phosphate (−TCP, 30%) (Danish Technological Institute, Denmark). The granules were coated with poly-lactic acid (PLA) 12%, in order to increase the mechanical strength of the material (Phusis, France). Scaffold granules Ø∼900–1400 μm, 80% porosity) in group 2 consisted of pure HA/-TCP (Fin Ceramica, Italy). For both groups, cells were incubated in the bioreactor for 2 weeks. Fresh culture medium supplemented with dexamethasone and ascorbic-acid was added every third or fourth day. Porous titanium alloy implants with diameter=length=10mm (Biomet, USA) were inserted bilaterally in each of the distal femurs of the sheep; thus 4 implants in each sheep. The concentric gap (2 mm) surrounding the implant was filled with 1) BAG (autogenous), 2) granules, 3) granules+bone marrow aspirate (BMA, autologous) or 4) allograft. The sheep were euthanized after 6 weeks. Distal femurs were removed and implant-bone samples were divided in two parts. The superficial part was used for mechanical testing and micro-CT scanning, and the profound part for histomorphometry. Push-out tests were performed on an 858 Bionix MTS hydraulic materials testing machine. Shear mechanical properties between implant and newly generated bone were calculated to assess implant fixation. Results were assessed by One-way ANOVA. P-values less than 0.05 were considered significant. Results. One sheep in group 1 had to be euthanized after 4 weeks (excluded). One implant in each group was loosened and could not undergo push-out test (excluded). Group 1: No significant differences regarding failure energy (kJ/m2, p=0.44) or ultimate shear strength (MPa, p=0.17) could be seen. Shear stiffness (MPa) was significantly higher for the allograft group (p=0.04). Group 2: No significant differences regarding failure energy (p=0.11) or shear stiffness (p=0.52) could be seen. Ultimate shear strength was significantly higher for allograft (p=0.04). Results from μ-CT scanning and histomorphometry are pending. Discussion and Conclusion. The present study shows a possible effect of bioreactor activated bone substitute on early implant fixation. We are currently working on bone microarchitecture surrounding implant and histomorphometry. These results will aid in determining if BAG could make up a promising alternative for allograft as bone graft material

Aims

The aim of this study was to develop a psychometrically sound measure of recovery for use in patients who have suffered an open tibial fracture.

Aims

The aim of this study was to record the incidence of post-traumatic osteoarthritis (OA), the need for total hip arthroplasty (THA), and patient-reported outcome measures (PROMS) after surgery for a fracture of the acetabulum, in our centre.

Aims

To evaluate the outcomes of cemented total hip arthroplasty (THA) following a fracture of the acetabulum, with evaluation of risk factors and comparison with a patient group with no history of fracture.