Standard AP Research Articles

Peripheral organ doses from radiotherapy for heterotopic ossification of non-hip joints: Is there a risk for radiation-induced malignancies?

Radiotherapy, used for heterotopic ossification (HO) management, may increase radiation risk to patients. This study aimed to determine the peripheral dose to radiosensitive organs and the associated cancer risks due to radiotherapy of HO in common non-hip joints. A Monte Carlo model of a medical linear accelerator combined with a mathematical phantom representing an average adult patient were employed to simulate radiotherapy for HO with standard AP and PA fields in the regions of shoulder, elbow and knee. Radiation dose to all out-of-field radiosensitive organs defined by the International Commission on Radiological Protection was calculated. Cancer induction risk was estimated using organ-specific risk coefficients. Organ dose change with increased field dimensions was also evaluated. Radiation therapy for HO with a 7 Gy target dose in the sites of shoulder, elbow and knee, resulted in the following equivalent organ dose ranges of 0.85–62 mSv, 0.28–1.6 mSv and 0.04–1.6 mSv, respectively. Respective ranges for cancer risk were 0–5.1, 0–0.6 and 0–1.3 cases per 104 persons. Increasing the field size caused an average increase of peripheral doses by 15–20%. Individual organ dose increase depends upon the primary treatment site and the distance between organ of interest and treatment volume. Relatively increased risks of more than 1 case per 10,000 patients were found for skin, breast and thyroid malignancies after treatment in the region of shoulder and for skin cancer following elbow irradiation. The estimated risk for inducing any other malignant disease ranges from negligible to low.

Classifications In Brief: Paprosky Classification of Acetabular Bone Loss

Classifications In Brief: Paprosky Classification of Acetabular Bone Loss

The absence of a metal-on-metal bearing does not preclude the formation of a destructive pseudotumor in the hip—a case report

The absence of a metal-on-metal bearing does not preclude the formation of a destructive pseudotumor in the hip—a case report

The self-aligning knee prosthesis: clinical and radiological outcome and survival analysis of a cruciate retaining meniscal bearing knee at 10-year follow-up

Previously, the clinical and radiological results of the self-aligning cruciate retaining total knee prosthesis at 5-years follow-up were described. The 10-year follow-up is now reported to determine the clinical and radiological results and the survival of the prosthesis. A 10-year follow-up was performed in this prospectively followed cohort of 246 (232 patients) self-aligning, cruciate retaining total knee arthroplasties performed between 1995 and 1998. Because patients had died and others suffered from comorbidities making them unable to attend a follow-up consultation, data could be obtained for 105 prostheses. Clinical results were evaluated by the Knee Society Score, and radiological follow-up was performed on standard AP and lateral X-rays. All radiographs were evaluated for the presence of radiolucencies, osteolysis and wear. At the 10-year follow-up, there were no new cases of revision so that the cumulative survival rate at 10 years remains 95%. The 10-year follow-up shows good clinical results with an average Knee Society Score of 154 (SD 35.7) and an average range of motion of 109° (SD 13.7). After excluding 25 prostheses for comorbidities, the mean 10-year KSS score increased from 154 to 163 (SD 26.2). On the other hand, for the ROM, the exclusion of the 25 prostheses had no influence on the mean ROM value of 109°. At the 10-year follow-up, none of the 100 available radiographs showed any radiolucencies >2 mm on any component. Long-term follow-up of the mobile bearing, cruciate retaining, SAL-II total knee arthroplasty shows excellent clinical and radiological results without bearing dislocation. Prospective cohort, Level IV.

TU‐A‐116‐01: Phantom Measurement of Surface and Organ Dose Using Optically Stimulated Luminescence Detectors in Diagnostic Radiology

Purpose: To measure the organ and surface dose in a phantom using aluminum oxide doped with carbon (Al2O3:C) and beryllium oxide (BeO) optically stimulated luminescence (OSL) detectors for the purpose of evaluating patient organ dose in diagnostic radiology procedures. Methods: The Al2O3 :C detectors used in this study were cut from Luxel™ tape into 4 mm diameter circles of thickness 0.3 mm. The BeO detectors used in this study were ∼4.7 mm × ∼4.7 mm × 0.5 mm chips. The liver dose was measured by placing detectors into the custom‐made detector holders and placing the holders in the 19 locations corresponding to the liver in an anthropomorphic phantom (RANDO). Each measurement was repeated three times. An AP abdomen protocol with AEC was used to determine the technical parameters for the exam. After irradiations, the BeO signal was read using a Riso TL/OSL‐DA‐15 automated reader and the Al2O3 :C signal was read using a custom‐built light emitting diode (LED)‐based reader system. The results were compared to those obtained from LiF:Mg,Ti thermoluminescence detectors (TLD). Results: The liver dose measured by BeO and Al2O3:C for a standard AP abdomen exam was found to be 208 and 222 μGy, respectively. The surface dose measured by BeO and Al2O3:C exam was both found to be 540 μGy. For comparison, the TLDs measured an organ and surface dose of 257 and 630 μGy, respectively. Conclusion: The proposed method of using BeO and Al2O3:C OSL detectors to measure organ and surface dose in an anthropomorphic phantom yielded comparable results to that of TLDs and shows improved reproducibility of the measurements when compared to TLDs. Given the flexibility and accuracy of OSL detectors for various readout techniques, OSL detectors have a great potential to allow for clinical organ dose measurement of diagnostic x‐ray exams.

THU0414 Determination and quantification of synovial inflammation by magnetic resonance imaging in systemic sclerosis

BackgroundMagnetic resonance imaging (MRI) is useful method for detection and quantification of subclinical synovial inflammation and joint damage with better precision than radiography in systemic sclerosis (SSc). Early aggressive treatment...

Improving Accuracy and Confidence in Distal Radius Volar Plate Screw Placement through Supplemental Radiography: Examining Specialty, Education, and Experience Levels

The purpose of this study was to assess the extent to which a supplemental radiographic view increases accuracy and confidence ratings when determining screw placement in volar plating of distal radius fractures for evaluators of different specialties and experience levels. Thirty-four distal radius fractures treated with volar plate fixation were imaged using standard AP and lateral, and supplemental lateral tilt views. Each case was then evaluated for penetration of distal screw tips into the articular space. Sixty-five physicians then completed a two-phase analysis and survey of these cases. In the first phase, presentation consisted only of AP and lateral views; in the second, the lateral tilt view was added. Participants were asked to determine whether distal screws penetrated the joint and rate their confidence in the determination. Assessments were scored for correctness; changes in accuracy and confidence levels between phases were analyzed using paired t tests. Comparisons between groups were performed by ANOVA. Supplementation increased accuracy and confidence in all position, specialty, and experience groups. Confidence scores were significantly higher following evaluation of three views versus two views. Residents exhibited the greatest improvements in accuracy and confidence. For first-phase (standard view) assessments, accuracy scores were significantly better for attendings with less than 10years post-fellowship experience than those with more. A supplemental view of the distal radius combined with AP and lateral views significantly improves the ability of all evaluators, regardless of specialty or training level, to correctly assess placement of fixation screws. The greatest improvements are seen for resident trainees.

Fractures in Brief: Olecranon Fractures

Olecranon fractures are relatively common injuries, accounting for approximately 10% of upper extremity fractures in adults [26]. These fractures may result from a direct blow to the proximal ulna, or indirectly, via the forceful contraction of the triceps against resistance (typically, during a fall onto an outstretched hand). Less commonly, the olecranon may fracture when the elbow is hyperextended, as the bone is impacted against the olecranon fossa of the distal humerus. For unstable injuries, operative fixation typically is required. Even after recovery, loss of ROM is not uncommon. This article provides an overview of olecranon fractures in adults; therefore, discussion of olecranon fractures in skeletally immature patients is beyond the scope of this article.

AN EFFICIENT EVOLUTIONARY ALGORITHM FOR LOCATING LONG-TERM CARE FACILITIES

This paper deals with a variant of a discrete location problem of establishing long-term care facilities in a given network. The objective is to determine optimal locations for these facilities in order to minimize the maximum number of assigned patients to a single facility. We propose an efficient evolutionary approach (EA) for solving this problem, based on binary encoding, appropriate objective function and standard genetic operators. Unfeasible individuals in the population are corrected to be feasible, while applied EA strategies keep the feasibility of individuals and preserve the diversity of genetic material. The algorithm is benchmarked on a real-life test instance with 33 nodes and the obtained results are compared with the existing ones from the literature. The EA is additionally tested on new problem instances derived from the standard ORLIB AP hub data set with up to 400 potential locations. For the first time in the literature we report verified optimal solutions for most of the tested problem instances with up to 80 nodes obtained by the standard optimization tool CPLEX. Exhaustive computational experiments show that the EA approach quickly returns all optimal solutions for smaller problem instances, while large-scale instances are solved in a relatively short CPU time. The results obtained on the test problems of practical sizes clearly indicate the potential of the proposed evolutionary-based method for solving this problem and similar discrete location problems. DOI: http://dx.doi.org/10.5755/j01.itc.41.1.1115

Le fratture dell’estremo distale di femore e della tibia: la nostra esperienza con la tecnica MIPO

A retrospective evaluation of radiographic/clinical outcomes and postoperative complications, in patients treated for distal femur and tibia fractures with MIPO technique was performed. Between March 2009 and December 2010, at the University Hospital of Rome we treated 25 patients (28 fractures) with distal femur and distal tibia fractures using the MIPO technique. The mean age of the patients was 50 years, 21 with distal femur and 7 with distal tibia fractures. AO classification system was used. Minimum follow up was of 6 months (6–20). Participants also completed the Lysholm and Olerud/Molander questionnaire to provide a subjective measure of knee and anke function. Radiographic assessment was performed post-operatively and consequently every 2 months up to 1 year using the standard AP and LL views. Damage control was used when necessary. The mean healing time was 12 weeks. No significant varus/valgus deformities or rotational defects were detected. We observed very good clinical outcomes with high range of motion and complete weight bearing after bone healing. A high Lysholm and Olerud/Molander questionnaire score was obtained. There were no cases of pseudoartrosis, superficial/deep infection, implant failure or hardware impingement. To date none of these implants was removed. Several studies have observed very good outcomes and a very low rate of complications in treating these fractures with MIPO technique. Our experience confirms the validity of the technique.

Minimum ten-year follow-up of acetabular fracture fixation from the Irish tertiary referral centre

BackgroundSuccessful outcome from acetabular fracture fixation is multi-factorial. Long-term results are not frequently reported. Pooling such data from high output centres will help progress acetabular fixation. This paper presents the first ten-year data from the Irish tertiary referral centre. AimTo audit the radiographic and clinical outcome of all patients who had acetabular fracture fixation in the unit a minimum of ten years previously. MethodsPatients were identified from the unit database. Each patient was contacted and invited to attend the hospital for clinical and radiographic review. Clinical review consisted of examination and three separate scoring systems using both subjective and objective parameters. Radiographic review consisted of a standard AP pelvis and Judet views. ResultsForty-four patients were identified. Follow up of 68% was achieved. Total hip arthroplasty rate was 13.8%. Twenty percent of the remaining native hips had radiographic evidence of established arthritis. Sixty-three percent of functional outcome scores were classified as ‘good’ or ‘excellent’. Radiographic and functional data did not strongly correlate. The strongest correlating factor with poor functional outcome was concurrent injuries, particularly sciatic nerve injury. ConclusionsThese data support the role of operative intervention for acetabular fractures in a tertiary referral centre and allow better counselling of patients on prognosis.

Radiographies under Traction Influence Surgeon Choice in Implant Selection for Intertrochanteric Fractures

Objective: Determine whether preoperative AP pelvis radiographies under manual traction influence surgeon choice for implants in intertrochanteric fractures compared with standard radiographies. Methods: Fifty-eight patients with intertrochanteric fractures were prospectively enrolled from four tertiary teaching hospitals. All patients had standard AP pelvis radiographies taken as well as radiographies under manual traction of affected limb, 116 images total. Three fellowship trained trauma surgeons and three hip surgeons blindly reviewed the images and indicated their implant choice for each case: extra or intramedullary fixation. The observers received randomly assigned images and were unaware of the radiography technique, patient number, and repetition of patients within the set of images. Statistical analyses were performed using Cohen Kappa method and McNemar, Q Cochran, and Wilcoxon tests. Results: Manual traction radiographies changed surgeon-implant choice in 35.06% (range: 27.6% to 43.1%). However, traction radiographies provided no improvement in weak inter-observer reliability for treatment indication (k=0.264, p<0.001) compared to standard radiographies (k=0.220, p<0.001), when using Mann-Whitney test (p=0.359). Traction views did not increase predilection for either method. Hip surgeons agreed more than trauma surgeons concerning implant choice. Conclusions: Manual traction radiographies modified surgeon choice in up to one third of intertrochanteric fracture cases.

Résultats d’une chirurgie prophylactique dans la déformation de Madelung par la résection isolée du ligament radio-lunaire

Madelung's deformity is a bone dysplasia that occurs predominantly in adolescent females, characterized by early epiphyseal growth arrest in the medial part of the distal radius. This leads to an upward and medial displacement of the radial joint surface, restricting range of motion.The objective of this study was to determine whether there was a link between clinical and radiological data in children with Madelung's deformity and to test the hypothesis of a relation between the deformity and a genetic mutation.A retrospective study recruited 13 patients with Madelung's deformity, with a mean age of 13.2 years (range, 8–18 years). Assessment comprised level of pain, range of motion and grip force, with standard AP and lateral wrist X-rays. Every patient except one underwent molecular genetic screening, adhering to current recommendations.Pronation-supination, radial inclination and grip force were significantly impaired compared to normal results. All X-ray measurements were significantly abnormal, except for the lunate-covering ratio. Genetic mutation (SHOX) was systematic in the 12 patients screened.Radiological deformity did not correlate with functional disturbance or pain. Non-acquired Madelung's deformity requires molecular screening for SHOX or XO mutation, which definitively diagnoses Léri-Weill dyschondrosteosis or Turner syndrome.A larger series is necessary to confirm these preliminary results, which nevertheless suggest that non-acquired Madelung's deformity is not isolated but syndromic. Early detection of Léri-Weill or Turner syndrome is essential, due to their therapeutic specificities.IV.

Validation of a statistical shape model-based 2D/3D reconstruction method for determination of cup orientation after THA

The aim of this study was to validate the accuracy and reproducibility of a statistical shape model-based 2D/3D reconstruction method for determining cup orientation after total hip arthroplasty. With a statistical shape model, this method allows reconstructing a patient-specific 3D-model of the pelvis from a standard AP X-ray radiograph. Cup orientation (inclination and anteversion) is then calculated with respect to the anterior pelvic plane that is derived from the reconstructed model. The validation study was conducted retrospectively on datasets of 29 patients (31 hips). Among them, there were 15 men (15 hips) and 14 women (16 hips). The average age of the patients was 69.4±8.5(49-82) years. Each dataset has one postoperative X-ray radiograph and one postoperative CT scan. The postoperative CT scan for each patient was used to establish the ground truth for the cup orientation. The cup anteversion and inclination that were calculated from the 2D/3D reconstruction method were compared to the associated ground truth. To validate reproducibility and reliability, two observers performed measurements for each dataset twice in order to measure the reproducibility and the reliability of the 2D/3D reconstruction method. Our validation study demonstrated a mean accuracy of 0.4 ± 1.8°(-2.6° to 3.3°) for inclination and a mean accuracy of 0.6±1.5°(-2.0° to 3.9°) for anteversion. Through the Bland-Altman analysis, no systematic errors in accuracy were detected. The method showed very good consistency for both parameters. Our validation results demonstrate that the statistical shape model-based 2D/3D reconstruction-based method is an accurate, consistent, and reproducible technique to measure cup orientation from postoperative X-ray radiographs. The best results were achieved with radiographs including the bilateral anterior superior iliac spines and the cranial part of non-fractured pelvises.

Pelvis and total hip arthroplasty acetabular component orientations in sitting and standing positions: Measurements reproductibility with EOS imaging system versus conventional radiographies

The literature has recently underlined the interest of pelvic and acetabular component orientation measurements in the standing and sitting position. Radiographic follow-up of total hip arthroplasty (THA) is based on standard AP and lateral X-rays. The use of EOS™ 2D imaging system reduces patient's radiation exposure compared to conventional X-rays. However, using this system, the validity and reproducibility of angular measurements, have not been studied yet for the measurement of pelvic and acetabular parameters in patients with THA. The EOS™ 2D imaging system offers similar advantages to conventional X-rays in the measurement of pelvic and acetabular orientation parameters which are commonly used. Five angular parameters characterizing pelvic tilt and acetabular cup orientation were determined using the same digital measurement Imagika™ software based on two series of standard X-rays and EOS™ 2D images acquired in both standing and sitting positions. Radiographs from 50 patients with unilateral THA were measured three times by two observers. Intra- and interobserver reproducibility using each method was independently studied then paired comparison was performed. The ICC and Spearman rank correlation coefficient demonstrated an excellent EOS/conventional X-ray correlation. According to the parameters, the mean difference between these two imaging modalities ranged from 0.30° to 3.43° (P<0.05). The intra- and interobserver variability ranged from ± 2.97° to ± 6.46° using the EOS™ imaging system and from ± 4.26° to ± 10.22° using conventional X-rays (P<0.05). The EOS™ 2D imaging system may replace conventional X-rays in the assessment and monitoring of pelvic and acetabular cup orientation in THA. Level III. Prospective diagnostic study.

Periacetabular Osteotomy: Validation of Intraoperative Fluoroscopic Monitoring of Acetabular Orientation

During periacetabular osteotomy (PAO) the acetabulum is reorientated and the correction monitored by one or more anteroposterior pelvic radiographs. Obtaining these images is time consuming and requires additional technical and personal resources. Such disadvantages could be overcome with the use of fluoroscopy. However, information obtained from fluoroscopy should have the same quality when compared to standard pelvic radiography. Our purpose was to define a suitable fluoroscopy setup and compare the information obtained from the fluoroscopic images to that obtained from a traditional anteroposterior pelvic radiograph. In a consecutive series of 22 patients the acetabular fragment was monitored by a defined intraoperative fluoroscopy setup in addition to a pelvic radiograph. The images were analyzed in random order utilizing common parameters to judge the quality of acetabular orientation. Agreement between the two images was assessed using kappa statistics and compared to the intra-observer reliability obtained from an independent experienced hip surgeon reading the same set of pelvic radiographs on two occasions. In 5 patients the radiation exposure during both fluoroscopy and standard AP pelvic radiography was measured and compared. Agreement of angular measurements of acetabular coverage and version as well as qualitative parameters of acetabular orientation and position between fluoroscopy and pelvic radiographs was at least equal to the intra-observer agreement of an independent experienced hip surgeon reviewing the pelvic radiographs alone. Significantly less radiation exposure was recorded with the use of fluoroscopy when compared to traditional pelvic radiography. We conclude that the use of intraoperative pelvic radiographs during PAO procedures can be replaced by fluoroscopy without quality impairment.

Anatomic attachment of the ACL. Comparison between radiological and CT analysis

The following hypothesis was tested: the location of the tibial and femoral anterior cruciate ligament (ACL) attachments will differ according to the measurement technique (plain radiographs or CT-scan) in relation to the anatomic frame of reference. 10 gross specimens were studied. The location of metallic reference pins implanted around the tibial and femoral ACL attachments was recorded with reference to the bone contours with a caliper on the anatomic preparation, with standard plain AP and lateral radiographs and with a CT-scan. Results were compared with appropriate statistical tests at a 0.05 level of significance. The mean ratio between the antero-posterior tibia measurement and the center of the ACL tibial attachment varied from 50 to 52%. The mean ratio between the medio-lateral tibia measurement and the center of the ACL tibial attachment varied from 49 to 51%. The mean ratio between the antero-posterior femur measurement and the center of the ACL femoral attachment varied from 74 to 80%. The results were significantly different between the three techniques (respectively P=0.003, P=0.02 and P=0.045). The paired differences were small (3% at the tibia, 6% at the femur). There was a strong correlation and a good agreement between the three techniques. It is likely that the small differences on the tibia have few, if any, clinical relevance. Both radiographic and CT-scan measurement techniques used during the present study have the potential to be used as quality control after ACL replacement. Diagnostic study-investigating a diagnostic test. Development of diagnostic criteria in a consecutive series of patients and a universally applied "gold" standard, Level II.

A simple way to aid accurate guide wire placement in dynamic hip screw fixation for intertrochanteric fractures of the femur

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.

Statistically Deformable 2D/3D Registration for Estimating Post-operative Cup Orientation from a Single Standard AP X-ray Radiograph

The widely used procedure of estimating post-operative cup orientation based on a single standard AP X-ray radiograph is known inaccurate, largely due to the wide variability in individual pelvic orientation relative to X-ray plate. CT-based 2D/3D rigid image registration methods have been developed to measure post-operative cup orientation. Although encouraging results have been reported, their extensive usage in clinical routine is still limited. This may be explained by their requirement of having a CT study of the patient at some point during treatment, which is not available for vast majority of Total Hip Arthroplasty procedures performed nowadays. To address this limitation, this article proposes a statistically deformable 2D/3D registration approach for estimating post-operative cup orientation. No CT study of the patient is required any more. Compared to ground truths established from post-operative CT images, the cup orientations measured by the present technique in a cadaver experiment showed differences of 1.7 +/- 1.4 degrees for anteversion and difference of 1.5 +/- 1.5 degrees for inclination. When the present technique was evaluated on patients' datasets, differences of 2.2 +/- 1.3 degrees and differences of 2.0 +/- 0.8 degrees were found for the anteversion and the inclination, respectively. The experimental results, though still preliminary, demonstrated the efficacy of the present approach.

Stress radiography for osteoarthritis of the knee: a new technique

Stress radiographs have been used for several years to detect the amount of varus/valgus knee laxity and to evaluate the degree of compartmental involvement in degenerative osteoarthritis. However, the popularity of these radiographic methods has been affected by their technical limits due to the x-ray exposure for the personnel involved and the variability of the stress forces applied. A device was developed with the aim to create a constant varus or valgus stress force to the knee with the patient in a supine position. The device does not require personal assistance during the actual film taking. Sixty consecutive patients where included in the study and measured prior to their total knee replacement. All patients had standard weight-bearing AP and lateral views as well as stress views in varus and valgus. Both knees were examined in full extension and 30° of flexion. The joint space width in both the lateral and medial compartments were measured and subsequently compared with the standard weight-bearing films. A significant decrease in joint space distance in the affected compartment was found in the stress radiographs compared with the standard weight-bearing views. The medial compartment was best examined with the knee extended and varus stress force (P<0.001) and for the lateral compartment 30° of flexion proved to be more efficient (P<0.01). In conclusion, this stress radiographic device offers a possibility to enhance the varus/valgus force in a standardized way compared to standard weight-bearing views of the knee. The reliability and reproducibility is high. It is suitable for clinical practice and a valuable tool in research.