Background. Radiation exposure remains a significant occupational hazard for Orthopaedic surgeons. There are no references values for trauma procedures performed with Image Intensifier (II). We aimed to determine and compare reference values for patient radiation exposure for common trauma operations, and to analyse the effect of surgeon grade on II usage. Methods. Data collected prospectively from 849 cases between 01/05/2013 and 01/10/2014 were analysed. Statistical analysis was performed to calculate reference values for dose area product (DAP), screening time (ST), and number of II images taken for common trauma procedures where n>9 (n=808). Results. Dynamic hip screw (DHS) fixation required significantly less radiation than proximal femoral nail (PFN) for intertrochanteric hip fractures for median DAP (668mG/cm2 vs 1040mG/cm2, p<0.001), ST (00:36 vs 00:48, p<0.001), and number of II images (65 vs 110, p<0.001). Radiation exposure was statistically significantly less when Consultant Orthopaedic surgeons were first surgeon compared to Staff grade doctors and Orthopaedic trainees for DAP (90.55mGy/cm2 vs 175.5mGy/cm2 vs 366.5mGy/cm2), screening time (00:26 vs 00:32 vs 00:36), and number of II images (49 vs 59 vs 66). Conclusions. We reported reference values for common trauma operations that are essential to enable monitoring of patient radiation exposure. PFN required greater radiation exposure than DHS for intertrochanteric hip fracture. Increased surgical experience lead to lower radiation exposure in trauma operations, which could be developed to assess trauma competence within surgical training. Level of evidence. III

Introduction and Objective. When using radiation intraoperatively, a surgeon should aim to maintain the dose as low as reasonably achievable to obtain the diagnostic or therapeutic goal. The UK Health Protection Agency reported mean radiation dose-area-product (DAP) of 4 Gy cm2 for hip procedures. We aimed to investigate factors associated with increased radiation exposure in fixation of proximal femur fractures. Materials and Methods. We assessed 369 neck of femur fractures between April 2019 and April 2020 in one district general hospital. Fractures were classified as extracapsular or intracapsular and into subtypes as per AO classification. Data was collected on type of fractures, implants used, level of surgeon, duration of surgery and DAP. Types of fractures were subclassified as complex (multifragmentary, subtrochanteric and reverse oblique) or simple. Results. Patients with fractures fixed with DHS, short PFNA, long PFNA and cannulated screws were included. 50% of our patients were fixed with hemiarthroplasty or total hip replacement and were therefore excluded. 184 patients were included in the analysis. There was a significant association of higher DAP with fracture subtype (P=0.001), fracture complexity (P<0.001), if an additional implant was used (P=0.001), if fixation was satisfactory (P=0.002) and the operative time (P<0.001). DAP was higher in PFNA than DHS and greatest in Long PFNA. There was some evidence of association between the level of the surgeon and DAP, although this was not statistically significant (P=0.069) and remained not significant after adjusting for the variables (fracture complexity, fixation or implant used) (p=0.32). Conclusions. Increased radiation in proximal femur fractures is seen in fixation of complex fractures, certain subtypes, the type of implant used and if an additional implant was required. Seniority of surgeon did not result in less radiation exposure even when adjusting for other factors, which is in contrast to other published studies

Aim. The knee radiograph is a commonly requested investigation as the knee joint is commonly injured. Each radiograph exposes 0.01mSv of radiation to the patient that is equivalent to 1.5 days of natural background radiation. Also, each knee radiograph costs approximately £37.16 to produce. The aim of the clinical audit was to use the Pittsburgh knee rules to attempt to reduce the number of knee radiographs taken in patients with acute knee injuries and hence reduce the dose of ionising radiation the patient receives. Method. A retrospective audit was undertaken. 149 knee requests and radiographs taken during October 2016 were evaluated. Each knee radiograph request including patient history and clinical examination was graded against the Pittsburgh knee rules to give a qualifying score. The Pittsburgh knee rules assigns 1 point for each of the following; blunt trauma or a fall, age less than 12 years or over 50 years, and unable to take 4 limping weight bearing steps in the emergency department. A Pittsburgh knee rule qualifying score warranting a knee radiograph is 2 or more points, where the patient must have had blunt trauma or a fall. A Pittsburgh knee rule score less than 2 points predicts a non-fractured knee and hence no radiograph warranted. Each radiograph was reviewed if a fracture was present or not. Results. The clinical audit identified 85 true negative patients where their Pittsburgh knee rule score was less than 2 points and they did not have a fracture of the knee joint. The Pittsburgh knee rule score of less than 2 points did not warrant obtaining knee radiographs. Therefore, a total of 85 knee radiographs were unnecessary which is equivalent to 127.5 days of background radiation. The financial burden of these unnecessary radiographs is £2648.60. The negative predictive value of the Pittsburgh knee rules in this audit was 93.4%. Discussion. The clinical audit shows that the use of the Pittsburgh knee rules scoring system can reduce the number of knee radiographs obtained by 57.4% and hence the doses of ionising radiation patients are exposed to. The audit also showed this clinical scoring system has a high negative predictive value that when utilised can discern patients with a normal knee joint who do not require a knee radiograph. In conclusion employing the Pittsburgh knee rule scoring system can improve patient safety by reducing ionising radiation exposure and can reduce financial costs of patient encounters

The ankle radiograph is a commonly requested investigation as the ankle joint is commonly injured. Each radiograph exposes 0.01 mSv of radiation to the patient that is equivalent to 1.5 days of natural background radiation [1]. The aim of the clinical audit was to use the Ottawa Ankle Rule to attempt to reduce the number of ankle radiographs taken in patients with acute ankle injuries and hence reduce the dose of ionising radiation the patient receives.

A retrospective audit was undertaken. 123 ankle radiograph requests and radiographs taken between May and July 2018 were evaluated. Each ankle radiograph request including patient history and clinical examination was graded against the Ottawa Ankle Rule. The rule states that 1 point(s) indicates radiograph series; (1) malleolar and/or midfoot pain; (1) tenderness over the posterior 6cm or tip of the lateral or medial malleolus (ankle); (1) tenderness over the navicular or the base of the fifth metatarsal (foot); (1) unable to take four steps both immediately and in the emergency department [2]. Patients who score 0 do not need radiograph series. Each radiograph was reviewed if a fracture was present or not.

The clinical audit identified 14 true positives where the Ottawa Ankle Rule scored 1 and the patient had an ankle fracture, and 2 false negatives (sensitivity 88%). There were 81 false positives, and 23 true negatives (specificity 22%). Therefore, a total of 23/123 ankle radiographs were unnecessary which is equivalent to 34.5 days of background radiation. The negative predictive value of the Ottawa Ankle Rule in this audit was 92%.

The low rate of Ottawa rule utilisation may unnecessarily cause patient harm that should be addressed. An educational intervention with physicians combined with integration of the Ottawa rule scoring in ankle radiograph requests is planned with re-audit in 6 months.

Abstract. Objectives. Knee alignment affects both the development and surgical treatment of knee osteoarthritis. Automating femorotibial angle (FTA) and hip-knee-ankle angle (HKA) measurement from radiographs could improve reliability and save time. Further, if the gold-standard HKA from full-limb radiographs could be accurately predicted from knee-only radiographs then the need for more expensive equipment and radiation exposure could be reduced. The aim of this research is to assess if deep learning methods can predict FTA and HKA angle from posteroanterior (PA) knee radiographs. Methods. Convolutional neural networks with densely connected final layers were trained to analyse PA knee radiographs from the Osteoarthritis Initiative (OAI) database with corresponding angle measurements. The FTA dataset with 6149 radiographs and HKA dataset with 2351 radiographs were split into training, validation and test datasets in a 70:15:15 ratio. Separate models were learnt for the prediction of FTA and HKA, which were trained using mean squared error as a loss function. Heat maps were used to identify the anatomical features within each image that most contributed to the predicted angles. Results. FTA could be predicted with errors less than 3° for 99.8% of images, and less than 1° for 89.5%. HKA prediction was less accurate than FTA but still high: 95.7% within 3°, and 68.0 % within 1°. Heat maps for both models were generally concentrated on the knee anatomy and could prove a valuable tool for assessing prediction reliability in clinical application. Conclusions. Deep learning techniques could enable fast, reliable and accurate predictions of both FTA and HKA from plain knee radiographs. This could lead to cost savings for healthcare providers and reduced radiation exposure for patients

The development and introduction of the closed locked intramedullary nail into clinical practice has revolutionized the treatment of fractures of long bone. The most difficult and technically demanding part of the procedure is often the insertion of the distal interlocking screws. A lot of efforts have been made during the past years to make it easier. In according with Whatling and Nokes, we can divide the different approaches to this issue in four main groups:. Free-hand (FH) technique;. Mechanical targeting devices mounted on image intensifier;. Mechanical targeting devices mounted onto nail handle;. Computer-assisted techniques. In addition of these, recently it has been proposed a navigational system using electromagnetic field. The main disadvantages of the FH technique, are prolonged exposure to radiation and results depend mostly on the dexterity of the surgeons. FH technique is however the most popular technique. Our targeting device is included into the mounted on image intensifier group. It consists of 2 radio-opaque rods at right angle to each over: one of this is fixed on the c-arm, whereas, the other is a sliding rod with a sleeve for the drill bit, which is the targeting guide itself. In the realization of this device, we have been inspired by the modification of the FH technique suggested by Kelley et al. To identify the distal holes we used the method described by Medoff (perfect circle). Once that the distal hole is seen as a perfect circle, with the C-arm in later view, the targeting guide is roughly positioned onto this and the drilling and the screwing operations are performed without the need for image intensifier. We used the device in bone models and in 9 clinical cases. In spite of authors demonstrated that the electromagnetic targeting device significantly reduced radiation exposure during placement of distal interlocking screws and was equivalent in accuracy when compared with the FH technique, the latter is the most used technique. Indeed, although all the studies have reported that the radiation exposure to orthopedic surgeon has been below the maximum allowable doses in all cases, there is still the risk of cumulative lifetime radiation exposure. From this point of view, namely the reduction of cumulative lifetime radiation exposure, we think that, paradoxically, our device could be more effective than electromagnetic targeting device, because it can be used in all the orthopedic operations that required a targeting device

Intramedullary nails (IMNs) are the current gold standard for treatment of long bone diaphyseal and selected metaphyseal fractures. Their design has undergone many revisions to improve fixation techniques, conform to the bone shape with appropriate anatomic fit, reduce operative time and radiation exposure, and extend the indication of the same implant for treatment of different fracture types with minimal soft tissue irritation. The IMNs are made or either titanium alloy or stainless steel and work as load-sharing internal splints along the long bone, usually accommodating locking elements – screws and blades, often featuring angular stability and offering different configurations for multiplanar fixation – to secure secondary fracture healing with callus formation in a relative-stability environment. Bone cement augmentation of the locking elements can modulate the construct stiffness, increase the surface area at the bone-implant interface, and prevent cut-through of the locking elements. The functional requirements of IMNs are related to maintaining fracture reduction in terms of length, alignment and rotation to enhance fracture healing. The load distribution during patient's activities is along the entire bone-nail interface, with nail length and anatomic fit being important factors to avoid stress risers

Freehand distal interlocking of intramedullary nails remains a challenging task. If not performed correctly it can be a time consuming and radiation expensive procedure. Recently, the AO Research Institute developed a new training device for Digitally Enhanced Hands-on Surgical Training (DEHST) that features practical skills training augmented with digital technologies, potentially improving surgical skills needed for distal interlocking. Aim of the study: To evaluate weather training with DEHST enhances the performance of novices without surgical experience in free-hand distal nail interlocking compared to a non-trained group of novices. 20 novices were assigned in two groups and performed distal interlocking of a tibia nail in an artificial bone model. Group 1: DEHST trained novices (virtual locking of five nail holes during one hour of training). Group 2: untrained novices without DEHST training. Time, number of x-rays, nail hole roundness, critical events and success rates were compared between the groups. Time to complete the task (sec.) and x-ray exposure (µGcm2) were significantly lower in Group1 414.7 (290–615) and 17.8 (9.8–26.4) compared to Group2 623.4 (339–1215) and 32.6 (16.1–55.3); p=0.041 and 0.003. Perfect circle roundness (%) was 95.0 (91.1–98.0) in Group 1 and 80.8 (70.1–88.9) in Group 2; p<0.001. In Group 1 90% of the participants achieved successful completion of the task (hit the nail with the drill), whereas only 60% of the participants in group 2 achieved this; p=0.121. Training with DEHST significantly enhances the performance of novices without surgical experience in distal interlocking of intramedullary nails. Besides radiation exposure and operation time the com-plication rate during the operation can be significantly reduced

Introduction. Transosseous flexion-distraction injuries of the spine typically require surgical intervention by stabilizing the fractured vertebra during healing with a pedicle-screw-rod constructs. As healing is taking place the load shifts from the implant back to the spine. Monitoring the load-induced deflection of the rods over time would allow quantifiable postoperative assessment of healing progress without the need for radiation exposure or frequent hospital visits. This approach, previously demonstrated to be effective in assessing fracture healing in long bones and monitoring posterolateral spinal fusion in sheep, is now being investigated for its potential in evaluating lumbar vertebra transosseous fracture healing. Method. Six human cadaveric spines were instrumented with pedicle-screws and rods spanning L3 vertebra. The spine was loaded in Flexion-Extension (FE), Lateral-Bending (LB) and Axial-Rotation (AR) with an intact L3 vertebra (representing a healed vertebra) and after transosseous disruption, creating an AO type B1 fracture. The implant load on the rod was measured using an implantable strain sensor (Monitor) on one rod and on the contralateral rod by a strain gauge to validate the Monitor's measurements. In parallel the range of motion (ROM) was assessed. Result. The ROM increased significantly in all directions in the fractured model (p≤0.049). The Monitor measured a significant increase in implant load in FE (p=0.002) and LB (p=0.045), however, not in AR. The strain gauge detected an increased implant load not only in FE (p=0.001) and LB (p=0.016), but also in AR (p=0.047). The highest strain signal was found during LB for both, the Monitor, and the strain gauge. Conclusion. After a complete transosseous disruption of L3 vertebra the load on the implants was significantly higher than in the intact respectively healed state. Innovative implantable sensors could be used to monitor those changes allowing the assessment of healing progression based on quantifiable data rather than CT-imaging

Abstract. Background. Post operative radiographs following total joint arthroplasty are requested as part of routine follow up in many institutions. These studies have a significant cost to the local departments, in terms of financial and clinic resources, however, previous research has suggested they may not alter the course of the patients treatment. The purpose of this study was to assess the significance of elective post operative radiographs on changes in management of patients who underwent total joint arthroplasty. Method. All patients who underwent total knee arthroplasty and total hip arthroplasty at a District General Hospital from 2019 to 2020 were included. Data was collected retrospectively from medical records and radiograph requests. Alterations to clinical management based on radiographic findings were reviewed in clinic letters. Results. A total of 227 Total joint arthroplasty were retrieved. With 111(49%) total hip arthroplasty and 116 (51%) total knee arthroplasty. 54 were excluded due to having no clinical follow up and 173 met inclusion criteria. 56 (32%) had their post operative elective radiograph, while 93 (53.8%) patients had none. There were no abnormalities detected from the elective radiographs and none of the patients returned to the theatre. 24 patients (13%) presented with symptoms and had non-elective radiographs, 16 (67%) did not have any interventions and 8 (4.6%) required intervention and were taken to theatre. Discussion: Not performing these radiographs saves time, cost, and prevents unnecessary radiation exposure. In our institution, a 2-view joint radiograph costs £29 and takes roughly 15 minutes. This does not include indirect costs of additional clinic time and patient waiting time. In the larger context, the cost associated with elective radiographs is significant and our data suggests that routine post-operative radiographs are not beneficial as part of standard post-operative protocol for asymptomatic patients. However, performing imaging remains beneficial for patients who re-present with symptoms. Conclusion. Routine elective post-operative joint radiographs did not detect any true abnormalities. Information from elective radiographs has no clinical significance and did not change management. Therefore, this study recommends that there is no rationale requesting elective post-operative joint radiographs. 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

Background. The anterior-posterior (AP) pelvis radiograph is crucial for diagnosis of neck of femur (NOF) fractures, especially as this is one of the commonest fractures in the elderly population. Anecdotally we found that initial AP pelvis radiographs for these suspected fractures did not always exhibit the bones sufficiently. Repeat radiographs were needed, leading to delays in diagnosis, treatment, and repeated radiation exposure. Missed diagnoses can have significant consequences for this patient group. We assessed how many initial AP pelvis radiographs taken for suspected NOF fracture fitted criteria for adequate diagnostic imaging. Methods. A retrospective study was carried out assessing the initial AP pelvis radiograph done for each patient presenting to our dedicated NOF unit with suspected NOF fracture for 1st June – 31st July 2014. European Guidelines for Diagnostic Imaging were used as the benchmark. Each radiograph was scored out of six, one for each criteria fulfilled. Guidelines deemed images scoring ≤3 as inadequate. Results. 76 images were assessed with mean patient age 85 years. 51.3% of images scored ≤3 and mean score was 3.59. The least-met criterion was “sharp reproduction of sacrum and vertebral foramina” (26.3%). Crucially only 52.6% achieved “visually sharp reproduction of spongiosa, trochanters and corticalis of both femurs”, important in diagnosis of NOF fractures. Conclusion. More than half initial AP pelvis radiographs taken for suspected NOF fracture were inadequate based on European Guidelines at a dedicated NOF unit. Part of the difficulty can be attributed to challenging patient demographics, however adequate initial radiographs should be aimed for, as repeat radiographs can lead to delays in diagnosis and treatment as well as repeated radiation exposure. Missed diagnoses can have significant consequences for this patient group; we particularly recommend care to be taken to sharply visualise the trochanters and proximal femora to avoid missing subtle fractures

Summary Statement. Using abdominal CT scans to evaluate bone mineral density following acute fractures of the thoracic and lumbar spine demonstrates significant levels of osteoporosis in older patients; this approach may help save on time and resources, and reduce unnecessary radiation exposure. Introduction. While a reduction in bone mineral density (BMD) is associated with aging, relatively few patients have formal dual-energy X-ray absorptiometry (DXA) to quantify the magnitude of bone loss, as they age. This loss of bone may predispose to fractures. Recent data, which correlates mean Hounsfield units (HU) in an area of the L1 vertebra with BMD, now makes it possible to screen for osteoporosis using incidental abdominal Computed Tomography (CT) scans to measure bone density. This innovation has the potential to reduce both cost and radiation exposure, and also make it easier to identify patients who may be at risk. The aims of this study were to evaluate the utility of this approach in patients with acute thoracic and lumbar spine fractures and to evaluate the impact of aging on BMD, using CT screening. Patients & Methods. Following institutional review board approval, we performed a retrospective study of patients who presented to a level I trauma center with acute fractures of the thoracic and lumbar spine between 2010 and 2013; patients also had to have had an abdominal (or L1) CT scan either during the admission or in the 6 months before or after their injury. Using a picture archiving and communication (PACS) system, we generated regions of interest (ROI) of similar size in the body of L1 (excluding the cortex) and computed mean values for HU. Values derived were compared against threshold values which differentiate between osteoporosis and osteopenia - for specificity of 90%, a threshold of 110 was set; for balanced sensitivity and specificity, a threshold of <135 HU was set and for 90% sensitivity a threshold of <160 HU was set. A student's t test was used to compare the age stratified mean HU (younger than 65yrs; 65yrs and older), while Fisher's exact test was used to perform aged stratified comparisons between the proportions of patients above and below the thresholds outlined (in each of the three threshold groups). Results. A total of 124 patients were evaluated, with 74 having thoracic and 50 having lumbar fractures. Among those with thoracic fractures, there were 33patients in the younger cohort, who also had a mean BMD of 196.51HU and 41 in the older cohort, who had mean BMD of 105.90HU (p<0.001). In patients with lumbar fractures, 27 patients were in the younger cohort, with mean BMD of 192.26HU and 23 patients in the older cohort with mean BMD of 114.31HU (p<0.001). At the threshold of 110 HU, set for specificity, the magnitude of difference between the age stratified cohorts was greater in the thoracic spine (p<0.001 vs. p=0.003). At the other thresholds: 135HU (balanced for sensitivity and specificity) and 160 HU (90% sensitivity), age of 65 years or older was significantly associated with reduction in CT derived measure of BMD (p<0.001 in all cases). Discussion. This study demonstrates the relative frequency of osteoporosis in acute fractures of the thoracic and lumbar spine, and how this changes with age; it is also the first study to do this using opportunistic CT scans. There seems to be a strong association between a reduction in bone mineral density and advanced age, in patients presenting with acute fractures of the spine. This approach may save on the extra cost and additional radiation exposure that may be associated with DXA scanning; in addition, it may help provide clinicians and patients with an approach to monitor developing problems with BMD before it becomes clinically apparent, especially in younger patients

The current standard of practice following knee arthroplasty is to demonstrate the appropriate alignment of knee replacements using knee radiographs. Recent studies have suggested that standard knee radiographs provide adequate accuracy for tibial prosthesis alignment assessment as compared with long knee view radiographs which are more technically demanding and carry greater radiation exposure. In this study, we aim to address whether alignment measured on standard knee radiographs are reliable and reproducible over time. We examined a cohort of 80 patients 37 male (46%), 43 females (54%), mean age = 68 years) who underwent total knee arthroplasty (TKA). Standard knee anteroposterior radiographs performed within 2 days following surgery were compared to standard knee anteroposterior radiographs taken 1 year following the surgery in patients with well-functioning prosthesis. Tibial prosthesis alignment angles between the longitude of the tibial shaft and the tibial baseplate were calculated using Centricity Enterprise Web V3.0 software. The data was examined using R software. In well-functioning primary knee arthroplasties, tibial prosthesis alignment angles measured in the 1-year follow-up standard view knee radiographs were found to deviate from measurements obtained with the same radiographic specifications in the immediate post-operative period. A significant mean percentage difference was found between the two radiographs. Long knee view radiographs may be required in order to accurately assess tibial prothesis alignment following total knee arthroplasty

Post-operative check radiographs following Total Hip Replacements (THR) are routine practice in most orthopaedic units. In our unit an Anteroposterior and Turned Lateral View (TLV) radiograph was used routinely in this assessment, but the TLV method has anecdotally been reported as painful by patients. We undertook a study to evaluate patients' experiences of pain using this technique and to consider if a change to a Horizontal Beam Lateral View (HBLV) radiograph method would result in a reduction in pain. The study was conducted in two phases. Patients who underwent a primary THR and subsequent post-operative TLV over 3months (n=46) were contacted by telephone and asked to grade their experience using a numerical and descriptive pain scale. After a change in practice to HBLV, the study was repeated (n=53) to identify any difference in pain. Ten radiographs were randomly selected from each group and assessed for radiation exposure and quality by two independent assessors. 87.0% of patients who underwent the TLV radiograph described the post-operative radiograph as painful, with a mean pain score of 7.44+1.5. After a change in practice to the HBLV radiograph, only 28.4% of patients experienced any pain, with a significantly lower mean pain score of 1.00+1.89 (p< 0.001). There was a significant increase in radiation dose in the HBLV vs. TLV method (62.4mAs vs. 25.8mAs, p< 0.001). HBLV X-ray quality was only slightly inferior to TLV when evaluating stem alignment and cement mantle quality. There was a dramatic reduction in both number of patients experiencing pain and level of pain experienced when switching from TLV to HBLV radiographs; this is most likely due to reduced direct pressure on the wound post-operatively. X-ray quality was not compromised, and whilst there was increased radiation exposure, the benefits in patient experience were felt to outweigh this. We recommend the HBLV radiograph method when performing a lateral post-operative check x-ray following THR

Objectives. The clinical utility of routine cross sectional imaging of the abdomen and pelvis in the screening and surveillance of patients with primary soft-tissue sarcoma of the extremities for metastatic disease is controversial, based on its questionable yield paired with concerns regarding the risks of radiation exposure, cost, and morbidity resulting from false positive findings. Methods. Through retrospective review of 140 patients of all ages (mean 53 years; 2 to 88) diagnosed with soft-tissue sarcoma of the extremity with a mean follow-up of 33 months (0 to 291), we sought to determine the overall incidence of isolated abdominopelvic metastases, their temporal relationship to chest involvement, the rate of false positives, and to identify disparate rates of metastases based on sarcoma subtype. Results. A total of four patients (2.9%) exhibited isolated abdominopelvic metastatic disease during the surveillance period. In all cases of concomitant chest and abdominopelvic disease, chest involvement preceded abominopelvic involvement. There was a significant false positive rate requiring invasive workup. Conclusions. In the setting of a relative paucity of evidence concerning a rare disease process and in difference to recently published investigations, we add a clinical cohort not supportive of routine cross sectional imaging of the abdomen and pelvis. Cite this article: Bone Joint Res 2015;4:45–9

Summary Statement. It is now possible to diagnose osteoporosis using incidental abdominal CT scans; applying this approach to fractures of the cervical spine demonstrates levels of osteoporosis in patients over 65. Introduction. Recently published data now makes it possible to screen for osteoporosis in patients who, in the course of their hospital stay, have had Computed Tomography (CT) scans of their abdomen for reasons other than direct imaging. This is as a result of CT derived bone mineral density (BMD) in the first lumbar vertebra (L1) being correlated BMD derived from Dual-energy X-ray absorptiometry (DEXA) scans. The advantage of this is the reduction in both cost and radiation exposure. Although age has a detrimental effect on BMD, relatively few patients have formal DEXA studies. The aims of this study were to evaluate the utility of this new technique in a cohort of patients with acute fractures of the cervical spine and to compare relative values for BMD in patients aged over 65 with those aged under 65, and thus define the role of osteoporosis in these injuries. Methods & Patients. Following Institutional review board approval, we performed a retrospective study of patients who presented to a level I trauma center with acute fractures of the cervical spine between 2010 and 2013; patients also had to have had a CT scan of their L1 vertebra either during the admission or within 6 months of their admission (for any other clinical reason). Using a picture archiving and communication (PACS) system, we generated regions of interest (ROI) of similar size in the body of L1 (excluding the cortex), in line with the publication by Pickhardt et al., and computed the mean values for Hounsfield units (HU). These values were compared against established threshold values which differentiate between osteoporosis and osteopenia; for a balanced sensitivity and specificity, <135 HU is the threshold and for 90% sensitivity a HU threshold of <160 HU is set. Comparisons were also performed between age stratified groups. Results. A total of 187 patients were reviewed for eligibility, 91 patients met the criteria with 53 patients aged 64 years or younger (range 23–64) and 38 patients aged above 65 years (range 65–98). In the younger cohort, 6/53 (11% were osteoporotic, using the lower threshold, while the higher threshold indicated 5/53 (17%) of patients under 65 years were osteoporotic; mean HU for the group was 195.8 (SD 43.3). In the older cohort, 24/38 (63%) were osteoporotic using the lower threshold, whereas 34/38 (89%) were osteoporotic using the higher threshold. Mean HU for the cohort aged over 65 years was 118.7 (SD 38.4). Age based comparison of the mean values, regardless of threshold, was statistically significant (p<0.001) in both cases. Discussion and Conclusions. This study demonstrates, for the first time in the cervical spine (including C2), the role of age related osteoporosis in acute fractures of the cervical spine. This new technique harnessing the presence of opportunistic CT scans of the abdomen saves on the extra cost and radiation exposure that may be associated with DEXA scanning. In younger patients, the higher threshold indicated 17% were osteoporotic – in the setting of an opportunistic scan, this may afford them the opportunity to commence prophylactic treatment to prevent future fractures. We believe these result have the potential to significantly impact future clinical practice

The function of the knee joint is to allow for locomotion and is comprised of various bodily structures including the four major ligaments; medial collateral ligament (MCL), lateral collateral ligament (LCL), anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL). The primary function of the ligaments are to provide stability to the joint. The knee is prone to injury as a result of osteoarthritis as well as ligamentous and meniscal lesions. Furthermore, compromised joint integrity due to ligamentous injury may be a result of direct and indirect trauma, illness, occupational hazard as well as lifestyle. A device capable of non-invasively determining the condition of the ligaments in the knee joint would be a useful tool to assist the clinician in making a more informed diagnosis and prognosis of the injury. Furthermore, the device would potentially reduce the probability of a misdiagnosis, timely diagnosis and avoidable surgeries. The existing Laxmeter prototype (UK IPN: GB2520046) is a Stress Radiography Device currently limited to measuring the laxity of the MCL and LCL at multiple fixed degrees of knee flexion. Laxity refers to the measure of a ligament's elasticity and stiffness i.e. the condition of the ligament, by applying a known load (200N) to various aspects of the proximal tibial and thereby inducing tibial translation. The extent of translation would indicate the condition of the ligament. The Laxmeter does not feature a load applying component as of yet, however, it allows for the patient to be in the most comfortable and ideal position during radiographic laxity measurement testing. The entire structure is radiolucent and attempts to address the limitations of existing laxity measurement devices, which includes: excessive radiation exposure to the radiographic assistant, little consideration for patient ergonomics and restrictions to cruciate or collateral ligament laxity measurements. The study focusses on further developing and modifying the Laxmeter to allow for: the laxity measurement of all four major ligaments of the knee joint, foldability for improved storage and increased structural integrity. Additionally, a load applicator has been designed as an add-on to the system thereby making the Laxmeter a complete Stress Radiography Device. Various materials including Nylon, Polycarbonate, Ultra High Molecular Weight Polyethylene (UHMWPE) – PE 1000, and Acetal/ POM were tested, using the Low Dose X-ray (Lodox) scanner, to determine their radiolucency. All materials were found to be radiolucent enough for the manufacture of the Laxmeter structure as well as the load applicator in order to identify and measure the translation of the tibia with respect to the stationary femur. The Laxmeter allows for the measurement of the laxity of the MCL and LCL at multiple fixed degrees of flexion by providing the ideal patient position for testing. The next iteration of the device will present an affordable and complete Stress Radiography Device capable of measuring the laxity of all four major ligaments of the knee joint at multiple fixed degrees of flexion. Future work would include aesthetic considerations as well as an investigation into carbon-fibre-reinforced plastics

Non-invasive, in vivo measurement of the three-dimensional (3-D) motion of the tibiofemoral joint is essential for the study of the biomechanics and functional assessment of the knee. Real-time magnetic resonance imaging (MRI) techniques enable the measurement of dynamic motions of the knee with satisfactory image quality and free of radiation exposures but are limited to planar motions in selected slice(s). The aims of the current study were to propose a slice-to-volume registration (SVR) method in conjunction with dual-slice, real-time MRI for measuring 3-D tibiofemoral motion; and to evaluate its repeatability during passive knee flexion. Eight healthy young adults participated in the current study, giving informed written consent as approved by the Institutional Research Board. A 3-T MRI system (Verio, Siemens, Erlangen, Germany) incorporated with a neck matrix coil was used to collect the MRI data. A 3-D scanning using the VIBE sequence was used to collect the volumetric data of the knee at fully extended position (TR = 4.64 ms, TE = 2.3 ms, flip angle = 15°, in-plane resolution = 0.39 × 0.39 mm. 2. and slice thickness = 0.8 mm). A real-time MRI using the refocused radial FLASH sequence (TR = 4.3 ms, TE = 2.3 ms, flip angle = 20°, in-plane resolution = 1.0 × 1.0 mm. 2. , slice thickness = 6 mm) was used to acquire a pair of image slices of the knee at a frame rate of 3 fps during passive flexion. The volumetric MRI data sets were segmented for the femur and tibia/fibula to isolate the sub-volumes containing bone segments. A slice-to-volume registration method was then performed to determine the 3-D poses of the bones based on the spatial matching between sub-volume of the bones and the real-time image slices. The bone poses for all frames were used to calculate the rigid-body kinematics of the tibiofemoral joint in terms of the flexion/extension (FE), internal/external rotation (IR/ER), abduction/adduction (Abd/Add) and joint center translations along three anatomical axis of the tibia. The procedures were carried out five times for repeatability analysis. The standard deviation (SD) of the rigid-body kinematics for each frame from the five trials were calculated and then averaged across all frames to give quantitative measures of the repeatability of the kinematic variables. The repeatability analysis showed that the mean±SD of the averaged SD in FE, Abd/Add and IR/ER components across all subjects were 0.25±0.09, 0.46±0.13 and 0.77±0.16 degrees, respectively. The corresponding values for the joint translations in anterior/posterior, proximal/distal and medial/lateral directions were 0.21±0.04, 0.11±0.03 and 0.43±0.09 mm. An SVR method in conjunction with dual-slice real-time MRI has been successfully developed and its repeatability in measuring 3-D motion of the tibiofemoral joint evaluated. The results show that the proposed method is capable of providing rigid-body kinematics with sub-millimeter and sub-degree precision (repeatability). The proposed SVR method using real-time MRI will be a valuable tool for non-invasive, functional assessment of the knee without involving ionizing radiation, and may be further developed for joint stability assessment

Introduction. The use of the dynamic hip screw is common practice for the fixation of intertrochanteric fractures of the femur. The success of this procedure requires accurate guide wire placement. This can prove difficult at times and can result in repeated attempts leading to longer operating time, multiple tracks and more importantly greater radiation exposure to both patient and operating staff. We hypothesised that rather than using the standard anterior-posterior projected image (Figure 1) of a proximal femur, rotating the intensifier image (Figure 2) so that the guide wire appears to pass vertically makes it easier to visualise the projected direction of the guide wire. Methods. Fifty Specialist Registrars, thirty participating in the London hip meeting 2009, ten from Oxford and ten from Northern deanery orthopaedic rotations were involved in the study. They were presented with standard AP and rotated images of the femoral neck on paper using 135 degree template to replicate the DHS guide. The participants were asked to mark the entry point on the intertrochanteric area of femur on the image where they would have placed the guide wire. They did this on both standard AP and rotated images aiming for the centre of the head of the femur. Fig. 1 Standard AP image Fig. 2 Rotated image. Results. Thirty-seven Specialist Registrars (74%) were able to accurately mark their entry point on rotated images on their first attempt as compared to eighteen trainees (36%) managing to place it correctly first time on the standard image. Thirteen trainees (26%) were able to mark their entry point correctly on both standard AP and rotated images with equal accuracy. Conclusion. Coren et al. 1 argue that human vision can more easily judge horizontal and vertical lines rather than oblique lines. Thus, rather than use the standard anterior-posterior projected image of the hip, we should routinely rotate the intensifier image so that the guide wire appears to be passing in a vertical direction. By rotating the image (Figure 2) in this way it becomes significantly easier to visualise the projected direction of the guide wire and in doing so ensure its accurate final placement thereby minimising possible complications

Summary. Low energy irradiation of vitamin E blended UHMWPE is feasible to fabricate total joint implants with high wear resistance and impact strength. Introduction. Irradiated ultra-high molecular weight polyethylene (UHMWPE), used in the fabrication of joint implants, has increased wear resistance. But, increased crosslinking decreases the mechanical strength of the polymer, thus limiting the crosslinking to the surface is desirable. Here, we used electron beam irradiation with low energy electrons to limit the penetration of the radiation exposure and achieve surface cross-linking. Methods. Medical grade 0.1wt% vitamin E blended UHMWPE (GUR1050) was consolidated and irradiated using an electron beam at 0.8 and 3 MeV to 150 kGy. Fourier Transform Infrared Spectroscopy (FTIR) was used from the surface along the depth at an average of 32 scans and a resolution of 4 cm. −1. A transvinylene index (TVI) was calculated by normalizing the absorbance at 965 cm. −1. (950–980cm. −1. ) against 1895 cm. −1. (1850 – 1985 cm. −1. ). TVI in irradiated UHMWPE is linearly correlated with the radiation received [3]. Vitamin E indices were calculated as the ratio of the area under 1265 cm. −1. (1245–1275 cm. −1. ) normalized by the same. Pin-on-disc (POD) wear testing was conducted on cylindrical pins (9 mm dia., 13 mm length, n=3) as previously described at 2 Hz [4] for 1.2 million cycles (MC). Wear rate was measured as the linear regression of gravimetric weight change vs. number of cycles from 0.5 to 1.2 MC. Double notched IZOD impact testing was performed (63.5 × 12.7 × 6.35mm) in accordance with ASTM F648. Cubes (1 cm) from 0.1wt% blended and 150 kGy irradiated pucks (0.8 MeV) were soaked in vitamin E at 110°C for 1 hour followed by homogenization at 130°C for 48 hours. Results. The penetration of the electron beam for cross-linking was limited at low beam energy and cross-linking of the surface 2 mm was achieved. The wear rate of samples irradiated at 0.8 and 3 MeV was 1.12±0.15, and 0.98±0.11, respectively (p»0.5). In addition, the wear rate of the surface (0.8 MeV) irradiated UHMWPE was 0.33±0.02 mg/MC 1 mm below the surface. The impact strength of UHMWPE irradiated at 0.8 MeV was 73 kJ/m. 2. and 54.2 kJ/m. 2. for that irradiated at 3 MeV (p=0.001). Doping with vitamin E and homogenization increased the surface vitamin E concentration from undetectable levels to 0.11±0.01. Discussion. The wear rate of this surface cross-linked UHMWPE was comparable to uniformly cross-linked UHMWPEs irradiated at higher electron beam energies. Even lower wear rate subsurface suggested the feasibility of machining 1 mm from the surface in implant fabrication. Limiting cross-linking to the surface resulted in higher impact strength compared to a uniformly cross-linked UHMWPE. Vitamin E was optionally replenished by additional doping after cross-linking; an advantage of this method may be increased oxidation resistance