C. Difficile infections in elderly patients with hip fractures is associated with high morbidity and mortality. Antibiotic regimens with penicillin and its derivatives is a leading cause. Antibiotic prophylactic preferences vary across different hospitals within NHS. We compared two antibiotic prophylactic regimens - Cefuroxime only prophylaxis and Teicoplanin with Gentamicin prophylaxis in fracture neck of femur surgery, and evaluated the incidence of C. Difficile diarrhea and Surgical Site Infection (SSI). To assess the Surgical Site Infection and C. Difficile infection rate associated with different regimens of antibiotics prophylaxis in fracture neck of femur surgery. Data was analyzed retrospectively. Neck of femur fracture patients treated surgically from 2009 in our unit were included. Age, gender, co morbidities, type of fracture, operation, ASA grade was collected. 1242 patients received Cefuroxime only prophylaxis between January 2009 and December 2012 (Group 1) and 486 patients received Teicoplanin with Gentamicin between October 2015 and March 2017 (Group 2). There were 353 males and 889 female patients in Group 1 and 138 males and 348 female patients in Group 2. The co morbidities in both groups were comparable. Incidence of C. Difficile diarrhea and Surgical Site Infection (SSI) was noted. Statistical analysis with chi square test was performed to determine the ‘p’ value. C. Diff diarrhea rate in Group 2 was 0.41 % as compared to 1.29 % in Group 1. The Surgical Site Infection (SSI) rate in Group 2 was 0.41 % as compared to 3.06 % in Group 1. The comparative results were statistically significant (p = 0.0009). Prophylactic antibiotic regimen of Teicoplanin with Gentamicin showed significant reduction in C. Difficile diarrhea & Surgical Site Infection in fracture neck of femur patients undergoing surgery

The femur is a common site for skeletal bony metastases. The aim of this study is to evaluate the outcomes of femoral intramedullary nailing in prophylactic versus therapeutic treatment in femoral metastases. All femoral nails between April 2011 and November 2015 at a district general hospital were assessed. Intramedullary nailing performed for prophylactic or therapeutic management were included. Outcomes include mortality, survival time and length of stay in hospital. A total of 40 cases were included. In the prophylactic group there were 25 patients and in the therapeutic group there were 15 patients. In the prophylactic group, mean age was 70 years (range 41–91); male to female ratio is 23:17 and 26 patients of this group was deceased. In the therapeutic group, mean age was 76 years (range 56–92); male to female ratio 15:10 and 10 patients were deceased in this group. The most common primary was prostate carcinoma followed by breast carcinoma. In the prophylactic group, mean survival was 25 weeks (range 2–147) and in the therapeutic group mean survival was 20 weeks (range 2–39). The length of stay was 21 days (range 3–80) in the prophylactic group and 28 days (range 7–63) in the therapeutic group. Femoral nailing for metastases helps improve quality of life and we observed a mean survival time of 20–25 weeks postoperatively in both therapeutic and prophylactic nailing

Introduction. Perioperative antibiotic prophylaxis use in modern orthopaedic procedures is well established. Studies have shown significant reduction in risk of post-operative infections. However, as effectiveness of these antibiotics is dependent on achieving high serum and tissue concentrations that exceed the minimum inhibitory concentrations of infective organisms for operation duration, the timing of prophylaxis is crucial. Although, optimal timing for administering prophylaxis varies in the literature, 30 to 60 minutes prior to skin incision or inflation of tourniquet is considered best standards. Objectives. To audit our practice of timing of administration of perioperative prophylactic antibiotics in trauma and orthopaedic procedures. Methods. A double-centre prospective analysis was conducted over a period of 2 week (trauma) and 2 months (elective). Centre A involved trauma cases where centre B involved elective Total Knee Arthroplasty cases. Patients were excluded if they were already on regular antibiotics or when prophylaxis was not indicated. Prescription charts and anaesthetic charts were reviewed along with electronic theatre database. Results. A total of 109 patients were included (52 elective and 57 trauma). Only 21% of patients received prophylactic antibiotics within 30 to 60 minutes of knife to skin time or inflation of tourniquet. Two third of patients received prophylaxis earlier than recommended with 28% receiving prophylaxis between 5 to 10 minutes and 33% between 15 to 20 minutes prior to knife to skin time or inflation of tourniquet. Conclusions. Our audit highlights an important deviation from standard best practice. To address this problem we recommend a multidisciplinary team approach including anaesthetic, ward and theatre teams. Level of Evidence. III - Evidence from case, correlation, and comparative studies

Platelet-leucocyte gel (PLG), a new biotechnological blood product, has hitherto been used primarily to treat chronic ulcers and to promote soft-tissue and bone regeneration in a wide range of medical fields. In this study, the antimicrobial efficacy of PLG against Staphylococcus aureus (ATCC 25923) was investigated in a rabbit model of osteomyelitis. Autologous PLG was injected into the tibial canal after inoculation with Staph. aureus. The prophylactic efficacy of PLG was evaluated by microbiological, radiological and histological examination. Animal groups included a treatment group that received systemic cefazolin and a control group that received no treatment. Treatment with PLG or cefazolin significantly reduced radiological and histological severity scores compared to the control group. This result was confirmed by a significant reduction in the infection rate and the number of viable bacteria. Although not comparable to cefazolin, PLG exhibited antimicrobial efficacy in vivo and therefore represents a novel strategy to prevent bone infection in humans

Prophylactic augmentation is meant to reinforce the vertebral body (VB), but in some cases it is suspected to actually weaken it. To elucidate the biomechanical efficacy of prophylactic augmentation, the full-field three-dimensional strain distributions were measured for the first time inside prophylactic-augmented vertebrae. Twelve thoracic porcine vertebrae were assigned to three groups: 4 were augmented with bone cement for vertebroplasty (Mendec-Spine, Tecres), 4 were treated with another bone cement for vertebroplasty (Calcemex-Spine, Tecres) while the other 4 were tested untreated as a control. Destructive tests were carried out under axial compression, in a step-wise fashion (unloaded, 5%, 10% and 15% compression). At each loading step, μCT-images were acquired. The internal strain distribution was investigated by means of DVC analysis. Some augmented specimens were stronger than the respective control, while others were weaker. In most of the specimens, the strain distribution in the elastic regime (5% compression) seemed to predict the location of the micro-damage initiation before it actually became identifiable (at 10% and 15% compression). The measured strain had the same order of magnitude for all groups. However, in the control vertebrae, the highest strain would unpredictably appear at any location inside the VB. Conversely, for both augmentation groups, the highest strains were measured in the regions adjacent to the injected cement mass, whereas the cement-interdigitated-bone was less strained. Localization of high strains and failure was consistent between specimens, but different between the two cement types: with Mendec-Spine failure the highest strains were mainly localized at mid-height and at the same level where the cement mass was localized; with Calcemex-Spine failure the highest strains were mainly cranial and caudal to the cement mass. Both the micro-CT images, and the DVC strain analysis highlighted that:. The cement mass was less strained than any other regions in the vertebra. Failure never started inside the cement mass. This can be explained with the additional stiffening and reinforcement associated with the infiltration of the cement inside the trabecular bone. The highest strains and failure were localized in the bone adjacent to the cement-bone interdigitated region. This can be explained by the strain concentration between the cement-interdigitated bone (stiffer and stronger), and the adjacent non-augmented trabecular bone. The strain maps in the elastic regime and the localization of failure was different in the augmented vertebrae, when compared to the natural controls. This suggests an alteration of the load sharing in the augmented structure where the load is mostly carried by the cement region. The different localization of failure initiation between the two augmented groups could be explained by the different mechanical properties of the two cements. This study has demonstrated the potential of DVC in measuring the internal strain and failure in prophylactic-augmented vertebrae. It has been shown that failure starts inside the augmented VB, next to the injected cement mass. This can help establishing better criteria (in terms of localization of the cement mass) in order to improve clinical protocols for vertebroplasty surgical procedures

Whilst the SIGN Guidelines state that the use of prophylactic antibiotics in surgery unequivocally reduces major morbidity, reduces hospital costs and is likely to decrease overall consumption of antibiotics they state the chosen antibiotics must reflect local, disease-specific information about the common pathogens and their antimicrobial susceptibility. Growing healthcare concern regarding the rates of Clostridium Difficile (C. Diff) within the hospital setting have led to rationalised and better streamlined prescribing practice within the NHS. In NHS Lanarkshire this led to revised guidelines for prophylactic antibiotic use in Orthopaedics in 2010. Routine use of 3. rd. generation Cephalosporin has been replaced by Flucloxacillin 1g and Gentamicin 1mg/kg. Anecdotally the surgeons within our department were concerned that they were recognising more post-operative renal impairment than before 2010. Our study took 902 consecutive cases treated surgically with either Total Hip Replacement, Total Knee Replacement, Dynamic Hip Screw for fracture and Hemiarthroplasty for fracture since the introduction of the new antibiotic policy. We compared this with a similar number of cases treated with the same operations pre-2010. We looked at the pre admission Urea & Electrolystes compared with immediate post-operative results and applied the definition of Acute Kidney Injury (AKI) as defined by the Acute Kidney Injury Network. A. A rapid time course (less than 48 hours) and B. Reduction of kidney function either as an absolute increase in serum creatinine of ≥26.4μmol/l (≥0.3 mg/dl) or a percentage increase in serum creatinine of ≥50%. Based on this definition we found an increased rate of AKI of 13.7% after the introduction of the use of Gentamicin from 9.8% before its routine use. We wish to highlight that the routine widespread use of Gentamicin may be increasing the rate of acute renal dysfunction seen in Orthopaedic patients undergoing major surgery

Summary. There is little knowledge in surgeons about the guidelines for prophylactic antibiotics in patients with prosthetic joints when undergoing a dental procedure. This study confirms this and there is need for robust and universal guidelines given the disastrous nature of prosthetic infection. Introduction. Infection as an indication for revision has increased to 12 % of the total revisions (NJR 9. th. report). However, it is next to impossible to find out the cause for a delayed prosthetic infection. With increasing number of arthroplasty procedures, is there a need for prophylactic antibiotics in patients with prostheses?. Methods. At London Knee Meeting 2012, a total of 163 surgeons were asked to take part in a survey. This was to find out if they knew of any existing guidelines for prophylaxis for dental procedures, if there was a need to practice more uniformly, and if they recommend such prophylaxis to their patients routinely. The grade of the surgeon and their experience in years was also noted. Results. Among the 163 surgeons who participated, 102 (62.6%) were arthroplasty surgeons. Of these, 73 (71.5%) were consultants with 3 or more years of experience. For this study, responses from these 102 surgeons were taken into consideration. Out of the 102 surgeons, only 39 (38%) were aware of AAOS recommendations. However, only 26 (25.5%) felt the need for such prophylaxis, other 37 (36%) were not sure if such prophylaxis was necessary. The remaining 39 (38.5%) did not think the prophylaxis was necessary. There was no difference found in the responses between the consultant and non-consultant surgeons. Conclusions. From this survey, it is clear that there is no uniformity of the knowledge of existing recommendations for prophylaxis of such patients with prostheses. There is probably a need to develop robust guidelines for prophylaxis, given the devastating nature of an infected prosthesis

The high risk and the associated high mortality of secondary, contralateral hip fractures [1,2] could justify internal, invasive prophylactic reinforcement of the osteoporotic proximal femur to avoid these injuries in case of a low energy fall. Previous studies have demonstrated high potential of augmentation approaches [3,4,5], but to date there has no ideal solution been found. The development of optimized reinforcement strategies can be aided with validated computer simulation tools that can be used to evaluate new ideas. A validated non-linear finite element (FE) simulation tool was used here to predict the yield and fracture load of twelve osteoporotic or osteopenic proximal femora in sideways fall based on high resolution CT images. Various augmentation strategies using bone cement or novel metal implants were developed, optimized and virtually performed on the bone models. The relative strengthening compared to the non-augmented state was evaluated using case-specific FE analyses. Strengthening effect of the cement-based augmentation was linearly proportional to cement volume and was significantly affected by cement location. With the clinically acceptable 12.6 ± 1.2 ml volume and optimized location of the cement cloud, compared to the non-augmented state, 71 ± 26% (42 – 134%) and 217 ± 166% (83 – 509%) increase in yield force and energy was reached, respectively. These were significantly higher than previously published experimental results using the “central” cement location [5], which could be well predicted by our FE models. The optimized metal implant could provide even higher strengthening effect: 140 ± 39% (76 – 194%) increase in yield force and +357 ± 177% (132 – 691%) increase in yield energy. However, for metal implants, a higher risk of subcapital fractures was indicated. For both cement and metal, the originally weaker bones were strengthened exponentially more compared to the stronger ones. The ideal solution for prophylactic augmentation should provide an appropriate balance between the requirements of being clinically feasible, ethically acceptable and mechanically sufficient. Even with the optimized location, the cement-based approach may not provide enough strengthening effect and adequate reproducibility of the identified optimal cement cloud position may not be achieved clinically. While the metal implant based strategy appears to be able to deliver the required strengthening effect, the ethical acceptance of this more invasive option is questionable. Further development is therefore required to identify the ideal, clinically relevant augmentation strategy. This may involve new cement materials, less invasive metal implants, or a combination of both. The FE simulation approach presented here could help to screen the potential ideas and highlight promising candidates for experimental evaluation

Introduction

Recently, oxidative stress has been implicated in the development of osteonecrosis. Here we focused on vitamins with marked antioxidant potency to see whether their use might prevent the development of osteonecrosis associated with corticosteroid administration.

A painful “dreaded black line” (DBL) has been associated with progression to complete fractures in atypical femur fractures (AFF). Adjacent sclerosis, an unrecognized radiological finding, has been observed in relation to the DBL. We document its incidence, associated features, demographics and clinical progression. We reviewed plain radiographs of 109 incomplete AFFs between November 2006 and June 2021 for the presence of sclerosis adjacent to a DBL. Radiographs were reviewed for location of lesions, and presence of focal endosteal or periosteal thickening. We collected demographical data, type and duration of bisphosphonate therapy, and progression to fracture or need for prophylactic stabilization, with a 100% follow up of 72 months (8 – 184 months). 109 femurs in 86 patients were reviewed. Seventeen sclerotic DBLs were observed in 14 patients (3 bilateral), involving 15.6% of all femora and 29.8% of femora with DBLs. Location was mainly subtrochanteric (41.2%), proximal diaphyseal (35.3%) and mid-diaphyseal (23.5%), and were associated with endosteal or periosteal thickening. All patients were female, mostly Chinese (92.9%), with a mean age of 69 years. 12 patients (85.7%) had a history of alendronate therapy, and the remaining 2 patients had zoledronate and denosumab therapy respectively. Mean duration of bisphosphonate therapy was 62 months. 4 femora (23.5%) progressed to complete fractures that were surgically managed, whilst 6 femora (35.3%) required prophylactic fixation. Peri-lesional sclerosis in DBL is a new radiological finding in AFFs, predominantly found in the proximal half of the femur, at times bilateral, and are always associated with endosteal or periosteal thickening. As a high proportion of patients required surgical intervention, these lesions could suggest non-union of AFFs, similar to the sclerotic margins commonly seen in fractures with non-union. The recognition of and further research into this new feature could shed more light on the pathophysiological progression of AFFs

Introduction and Objective. Management of bone loss associated with bone contamination or infection represents a double biological and clinical challenge frequent in traumatology. The advent of new biomaterials can allow a different approach in the treatment of bone gap. The purpose of this study was to evaluate the prophylactic and therapeutic effectiveness of addition of a new absorbable bone substitute (BS) eluting different antibiotics in reconstruction of bone defects after infections and fractures with soft tissue damage. Materials and Methods. We conducted a review of patients with contaminated or infected bone defects treated using a new biomaterial, a porous composite of collagen matrices and Beta tricalcium phosphate (β TCP), able to provide a long-term release of different antibiotics. We have included treatment of osteomyelitis and osteosynthesis of exposed fracture (Gustilo Anderson 1–3b) or fractures with soft tissue damage and high risk of contamination. Surgical technique included debridement filling bone defect with BS eluting antibiotics, osteosynthesis (plate, nail, external fixator, kirschner wire), soft tissue coverage, and systemic antibiotic therapy. Radiographic and clinical data including complications (wound dehiscence, superficial or deep infection, osteomyelitis) were collected. Results. We treated 25 patients (21 male, 4 female) with mean age 47 yrs. (range 21–83). The locations treated (for incidence) was: 9 femurs (7 plates, 2 nail), 7 calcanei (one bilateral), 3 tibias, 2 forearms, 2 metatarsi, 2 hands, 1 elbow. 6 patients had large bone loss. 7 patients had bone infections (4 were Cierny Madern 4); 8 patients had osteosynthesis of exposed fractures Gustilo Anderson 1–3b (9 plate, one bilateral calcaneus). 8 patients had treatment for pseudoarthrosis of exposed fractures (6 femurs, 1 forearm, 1 metatarsus) and 3 patients a prophylactic treatment for calcaneal fractures with soft tissue damage. 4 deep infection were treated with multiple surgical debridement and new filling bone defect with BS eluting antibiotic with infection eradication. We have used a combination of vancomycin and gentamicin on 15 cases, vancomycin alone on 4 cases, combination of vancomycin and amikacin on 1 case and amikacin and Linezolid in a targeted multi drug resistance. At final follow-up functional outcome was good in all cases with bone healing. Conclusions. Extensive debridement is a fundamental requisite for eradication of bone infections and contamination. Filling of the bone void with loaded bio-composite eluting diversifiable local antibiotics with synergistic anti-biofilm activity is desirable. Treatment of this bone defects are advantaged when combining his reconstruction with BS and the possibility of release high antibiotic concentration at least for 10 days. This is an important complementing prophylactic and therapeutic antimicrobial option with adjuvant role to systemic therapy that enlarges the success rate

Renal Osteodystrophy is a type of metabolic bone disease characterized by bone mineralization deficiency due to electrolyte and endocrine abnormalities. Patients with chronic kidney disease (CKD) are more likely to experience falls and fractures due to renal osteodystrophy and the high prevalence of risk factors for falls. Treatment involves medical management to resolve the etiology of the underlying renal condition, as well as management (and prevention) of pathological fractures. A 66-year-old female patient, with severe osteoporosis and chronic kidney disease undergoing haemodialysis, has presented with multiple fractures along the years. She was submitted to bilateral proximal femoral nailing as fracture treatment on the left and prophylactically due to pathological bone injury on the right, followed by revision of the left nail with a longer one after varus angulation and fracture distal to the nail extremity. Meanwhile, the patient suffered a pathological fracture of the radial and cubital diaphysis and was submitted to conservative treatment with cast, with consolidation of the fracture. Posteriorly, she re-fractured these bones after a fall and repeated the conservative treatment. Clinical management: There is a multidisciplinary approach to manage the chronic illness of the patient, including medical management to resolve the etiology and consequences of her chronic kidney disease, pain control, conservative or surgical fracture management and prevention of falls. The incidence of chronic renal disease is increasing and the patients with this condition live longer than previously and are more physically active. Thus, patients may experience trauma as a direct result of increased physical activity in a setting of weakened pathologic bone. Their quality of life is primarily limited by musculoskeletal problems, such as bone pain, muscle weakness, growth retardation, and skeletal deformity. A multidisciplinary approach is required to treat these patients, controlling their chronic diseases, managing fractures and preventing falls

Abstract. Objective. To assess the prevalence of acetabular retroversion in patients presenting with Slipped Upper Femoral Epiphysis using both validated radiological signs and CT-angle measurements. Methods. A retrospective review of all cases involving surgical management for acute SUFE presenting to the Royal Children's Hospital, Melbourne were assessed from 2012–2018. Pre-operative plain radiographs were assessed for slip angle, validated radiological signs of retroversion (post wall/crossover/ischial spine sign) and standardised post-operative CT Scans were used to assess cranial and mid-acetabular version. Results. 116 SUFEs presented in 107 patients who underwent surgical intervention; 47 females and 60 boys, with an average age of 12.7 years (range 7.5–16.6 years). Complete radiological data was available for 91 patients (99 hips) with adequate axial CT imaging of both hips. 82% patients underwent pinning in situ (PIS) with subcapital realignment surgery (SRS) performed in 18% (slip angles >75°). Contralateral prophylactic hip PIS was performed in 72 patients (87%). On the slip side, 68% of patients had 1 or more radiological signs of retroversion in the slipped hip, with 60% on the contralateral side. The mean cranial and mid-acetabular version measurements were −8°(range −30 – 8°) and 10.5°(range −10 – 25°), respectively. Conclusions. Acetabular retroversion is rare in the normal population with studies reports ranging from 0–7%. This study showed an increased prevalence of 68% in SUFE patients, which is likely to be a primary anatomical abnormality, subsequently increasing the shear forces across the proximal femoral growth plate due to superior over-coverage. The resulting CAM lesion from SUFE in combination with the pincer lesion due to retroversion can lead to premature hip impingement and degeneration. Further larger studies are required to assess if acetabular retroversion is a true risk factor, and its role in helping guide management including prophylactic pinning. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

The Hospital (Trust) guidelines generally recommend 40mg of Low molecular weight heparin (LMWH) twice daily (BD) for all patients over 100kg for those undergoing total hip (THR) and knee replacements (TKR) respectively. British National Formulary (BNF) recommends 40mg of LMWH once daily (OD) for all patients regardless of their overall weight or body mass index (BMI). We evaluated the outcome of prophylactic LMWH dosage for patients undergoing THR and TKR by monitoring surgery related venous-thromboembolic events up to a minimum of three months after surgery. A retrospective audit was carried out after obtaining institutional approval and all consecutive elective patients weighing over 100kg and undergoing THR and TKR were included. All patients were followed up for a minimum of 3 months after their operation to investigate the dose of prophylactic LMWH received, and whether they had developed any venous thromboembolic events (VTE) post operatively. This was done using a combination of electronic notes, drug charts and deep venous thrombosis (DVT) or computed tomography pulmonary angiogram (CTPA) reports on the hospital/trust database. A total of 53 patients underwent elective THR (18) and TKR (35) between the period of March 2017 and September 2017. Forty-four patients received 40 mg OD and 9 patients had 40 mg BD. None of the patients developed a confirmed DVT or pulmonary embolism in the 3 months following surgery regardless of the dose received. We demonstrate that there is no clinical benefit in having patients over 100kg on twice daily LMWH with the aim of preventing post-op thromboembolic complications. This conclusion is in line with the BNF recommendations for VTE prophylaxis

Methods. A retrospective review of 80 patients with unilateral slipped capital femoral epiphysis from 1998–2012 was undertaken to determine the outcome of the unaffected hip. All patients were treated with either prophylactic single Richards screw fixation or observation of the uninvolved hip and were followed up for at least 12 months. The unaffected hip of 44 patients (mean age 12.6 years, range 9–17) had simultaneous prophylactic fixation and 36 patients (mean age 13.4 years, range 9–17.4) were managed with observation. Results. Sequential slip of the unaffected hip was noted in 10 patients (28 per cent) in the observation group and only in 1 patient (2 per cent) in the group managed with prophylactic fixation. A Fisher's exact test showed significantly high incidence of sequential slip in unaffected hips when managed with regular observation (p-value 0.002). Only 3 cases had symptomatic hardware on the unaffected side after prophylactic fixation with one requiring revision of the metal work; one had superficial wound infection treated with antibiotics. No cases had AVN or chondrolysis. Conclusion. Simultaneous prophylactic fixation of the unaffected hip significantly reduces the incidence of sequential slip in unilateral SCFE with minimal complications. Level of evidence. III

Prophylactic treatment is advised for metastatic bone disease patients with a high risk of fracture. Clinicians face the task of identifying these patients with high fracture risk and determining the optimal surgical treatment method. Subject-specific finite element (FE) models can aid in this decision process by predicting the mechanical effect of surgical treatment. In this study, we specifically evaluated the potential of FE models to simulate femoroplasty, as uncertainty remains whether this prophylactic procedure provides sufficient mechanical strengthening to the weight-bearing femur. In eight pairs of human cadaveric femurs artificial metastatic lesions were created. In each pair, an identical defect was milled in the left and right femur. Four pairs received a spherical lesion in the neck and the other four an ellipsoidal lesion in the intertrochanteric region, each at the medial, superior/lateral, anterior and posterior side, respectively. One femur of each pair was augmented with polymethylmethacrylate (5–10 ml), while the contralateral femur was left untreated. CT scans were made at three different time points: from the unaffected intact femurs, the defect femurs with lesion and the augmented femurs. Bone strength was measured by mechanical testing until failure in eight defect and eight augmented femurs. Nonlinear CT-based FE models were developed and validated against the experimentally measured bone strength. Subsequently, the validated FE model was applied to the available CT scans for the three different cases: intact (16 scans), defect (16) and augmented (8). The FE predicted strength was compared for the three different cases. The FE models predicted the experimental bone strength with a strong correspondence, both for the defect (R. 2. = 0.97, RMSE= 0.75 kN) and the augmented femurs (R. 2. = 0.90, RMSE = 0.98 kN). Although all lesions had a “moderate” to “high” risk for fracture according to the Mirels’ scoring system (score 7 or 8), three defect femurs did not fracture through the lesion (intertrochanteric anterior, lateral and posterior), indicating that these lesions did not act as a critical weak spot. In accordance with the experimental findings, the FE models indicated almost no reduction in strength between the intact and defect state for these femurs (0.02 ± 0.1%). For the remaining “critical” lesions, bone strength was reduced with 15.7% (± 14.9%) on average. The largest reduction was observed for lesions on the medial side (up to 43.1%). For the femurs with critical lesions, augmentation increased bone strength with 29.5% (± 29.7%) as compared to the defect cases, reaching strength values that were 2.5% (± 3.7%) higher than the intact bone strength. Our findings demonstrate that FE models can accurately predict the experimental bone strength before and after augmentation, thereby enabling to quantify the mechanical benefit of femoroplasty. This way FE models could aid in identifying suitable patients for whom femoroplasty provides sufficient increase in strength. For all lesions evaluated in this study, femoroplasty effectively restored the initial bone strength. Yet, additional studies on larger datasets with a wide variation of lesion types are required to confirm these results

Abstract. Background. Schwannomas are slow-growing, benign tumours normally originating from the Schwann cells of the nerve sheath. Intraosseous schwannoma accounts for 0.175% of primary bone tumours and extremely rare especially outside the axial skeleton. Monoclonal gammopathy has been associated with soft tissue schwannomas but never with the intraosseous variety. Presenting problem. A 55-year-old woman with a background of monoclonal gammopathy of undetermined significance (MGUS) presented with a 2-year history of right thigh pain. CT scan showed a well defined, lytic lesion with a thin peripheral rim of sclerosis in the midshaft of the femur. MRI displayed a hyperintense, well marginated and homogenous lesion. Definitive diagnosis was made based on the classical histopathological appearance of schwannoma. Clinical management. We managed our patient with local curettage and prophylactic cephalomedullary nailing on the basis of a high mirel score. Discussion. Intraosseous schwannomas are poorly understood but most commonly reported in middle-aged women. Radiologically, their differential diagnosis includes malignant bone tumours, solitary bone cysts, aneurysmal bone cysts and giant cell tumours. As a result, they are usually diagnosed incidentally on histology. Although malignant transformation is possible in soft tissue schwannomas, all intraosseous schwannomas reported to date have been benign. This case demonstrates the importance of suspecting intraosseous schwannoma as a differential diagnosis for lytic bone lesions to avoid the overtreatment of patients. We also highlight monoclonal gammopathy of undetermined significance as a potential risk factor for a poorly understood disease and make recommendations about the appropriate management of these lesions. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

There has been evidence of association between femoral shaft fractures and prolonged bisphosphonate therapy. We present a case series of bisphosphonate-associated fractures and invaluable lessons we have learnt. Over the last three years at our unit we have collected a case series of eight patients who have had atypical femoral fractures whilst on bisphosphonate therapy. We present illustrative cases, a summary of key findings, and invaluable lessons we have learnt. There was a long period of prodromal pain for two years before incomplete fractures developed. We speculate this is a warning sign of impending fracture. This may have been prevented with screening. Between incomplete fracture and complete fracture there was a short window of one month. Five patients presented with complete fracture, and three with thigh pain +/- evidence of incomplete fracture. Of the latter group all but one went on to develop complete fractures. The one patient who did not progress died six years after diagnosis. Of those five patients who presented with initial complete fracture, three patients recall thigh pain before fracture on further questioning. Despite being diaphyseal femoral fractures, there is a higher risk of neck of femur fractures in this patient cohort (both patients with initial interlocked nails subsequently developed neck of femur fractures soon after and were revised to cephalomedullary nails). Excluding one death from unrelated cause, only one patient has signs of complete fracture healing. All other patients are still receiving follow-up (mean 490 days). Three patients reported bilateral symptoms (pain). Two had had bilateral symptoms for one year. Both had visible incomplete fractures on further radiographic scrutiny; one underwent prophylactic cephalomedullary nailing, one was managed with active surveillance. We suggest that improved pain and radiographic changes of cortical healing may be misleading and should not be relied upon. Cephalomedullary nailing is the treatment of choice in these fractures due to higher risk of neck of femur fractures in this cohort. We suggest prompt prophylactic cephalomedullary nailing when radiographic incomplete fractures are identified due to a short window before progression to complete fracture, and the need to consider contralateral prophylactic nailing in patients describing bilateral symptoms. We speculate that thigh pain is a warning sign of impending fracture and fracture-progression can be prevented with appropriate screening

Patients with cancer and bone metastases can have an increased risk of fracturing their femur. Treatment is based on the impending fracture risk: patients with a high fracture risk are considered for prophylactic surgery, whereas low fracture risk patients are treated conservatively with radiotherapy to decrease pain. Current clinical guidelines suggest to determine fracture risk based on axial cortical involvement of the lesion on conventional radiographs, but that appears to be difficult. Therefore, we developed a patient-specific finite element (FE) computer model that has shown to be able to predict fracture risk in an experimental setting and in patients. The goal of this study was to determine whether patient-specific finite element (FE) computer models are better at predicting fracture risk for femoral bone metastases compared to clinical assessments based on axial cortical involvement on conventional radiographs, as described in current clinical guidelines. 45 patients (50 affected femurs) affected with predominantly lytic bone metastases who were treated with palliative radiotherapy for pain were included. CT scans were made and patients were followed for six months to determine whether or not they fractured their femur. Non-linear isotropic FE models were created with the patient-specific geometry and bone density obtained from the CT scans. Subsequently, an axial load was simulated on the models mimicking stance. Failure loads normalized for bodyweight (BW) were calculated for each femur. High and low fracture risks were determined using a failure load of 7.5 × BW as a threshold. Experienced assessors measured axial cortical involvement on conventional radiographs. Following clinical guidelines, patients with lesions larger than 30 mm were identified as having a high fracture risk. FE predictions were compared to clinical assessments by means of diagnostic accuracy values (sensitivity, specificity and positive (PPV) and negative predictive values (NPV)). Seven femurs (14%) fractured during follow-up. Median time to fracture was 8 weeks. FE models were better at predicting fracture risk in comparison to clinical assessments based on axial cortical involvement (sensitivity 100% vs. 86%, specificity 74% vs. 42%, PPV 39% vs. 19%, and NPV 100% vs. 95%, for the FE computer model vs. axial cortical involvement, respectively). We concluded that patient-specific FE computer models improve fracture risk predictions of femoral bone metastases in advanced cancer patients compared to clinical assessments based on axial cortical involvement, which is currently used in clinical guidelines. Therefore, we are initiating a pilot for clinical implementation of the FE model

Prophylactic antibiotics administered prior to joint arthroplasty have become standard practice. Due to concern over the risk that 2nd generation cephalosporins posed to the elderly, as regards clostridium difficile associated infections the antimicrobial management team in our unit changed the protocol for prophylactic antibiotics. As of 1st September 2009, flucloxacillin and gentamicin were preferred over cefuroxime as the first choice of prophylactic antibiotic. However, it was noted that postoperatively patients were experiencing a decrease in renal function. One hundred patients who underwent a total hip replacement following the policy change were randomly selected from the departmental joint arthroplasty database. This group was age and sex matched to 100 patients undergoing their surgery prior to the change. Data was collected on renal function, length of stay, antibiotic and age. Any change in renal function was categorised using the RIFLE criteria. Exclusion secondary to variations from protocol or treatment for femoral neck fractures resulted in a total number of 156 patients with 78 in each arm. The average age for both groups was 64 years. Non-parametric analysis of preoperative and postoperative serum creatinine concentrations and Glomerular Filtration Rate (GFR) demonstrated a significant difference between the two groups, showing that GFR decreased (p=0.041) and serum creatinine concentration increased (p=0.037) in the cohort receiving gentamicin. Classing the impaired renal function as: risk, injury or failure (RIFLE criteria) demonstrated a statistically significant difference for any criterion positive (p=0.016) but no significant difference for the specific RIFLE groups (p=0.068). Acknowledging the small numbers and potential confounders for renal impairment, this study was able to show a difference in renal function for patients receiving gentamicin over cefuroxime as prophylaxis for joint arthroplasty