Navigation versus fluoroscopy in minimalinvasive iliosacral screw placement.

INTRODUCTION: When needed operative treatment of sacral fractures is mostly performed with percutaneous iliosacral screw fixation. The advantage of navigation in insertion of pedicle screws already could be shown by former investigations. The aim of this investigation was now to analyze which influence iliosacral screw placement guided by navigation has on duration of surgery, radiation exposure and accuracy of screw placement compared to the technique guided by fluoroscopy. METHODS: 68 Consecutive patients with sacral fractures who have been treated by iliosacral screws were inclouded. Overall, 85 screws have been implanted in these patients. Beside of demographic data the duration of surgery, duration of radiation, dose of radiation and accuracy of screw placement were analyzed. RESULTS: When iliosacral screw placement was guided by navigation instead of fluoroscopy the dose of radiation per inserted screw (155.0 cGy*cm2 vs. 469.4 cGy*cm2 p < 0.0001) as well as the duration of radiation use (84.8 s vs. 147.5 s p < 0.0001) were significantly lower. The use of navigation lead to a significant reduction of duration of surgery (39.0 min vs. 60.1 min p < 0.01). The placement of the screws showed a significantly higher accuracy when performed by navigation (0 misplaced screws vs 6 misplaced screws-p < 0.0001). CONCLUSION: Based on these results minimal invasive iliosacral screw placement guided by navigation seems to be a safe procedure, which leads to a reduced exposure to radiation for the patient and the surgeon, a reduced duration of surgery as well as a higher accuracy of screw placement.

Establishing regions of interest of the lower leg and ankle for perioperative volumetric assessment with a portable 3D scanner in orthopedic and trauma surgery - a pilot study.

BACKGROUND: Soft tissue swelling assessment benefits from a reproducible and easy to use measurement method. Monitoring of the injured lower extremity is of clinical import during staged soft tissue management. Portable 3D scanners offer a novel and precise option to quantify and contrast the shapes and volumes of the injured and contralateral uninjured limbs. This study determined three regions of interest (ROI) within the lower extremity (lower leg, ankle and foot), that can be used to evaluate 3D volumetric assessment for staged soft tissue management in orthopedic and trauma surgery. METHODS: Twelve healthy volunteers (24 legs) were included in this cohort study. Scans of all three ROI were recorded with a portable 3D scanner (Artec, 3D scanner EVA) and compared between the right and left leg using the software Artec Studio (Arctec Group, Luxemburg). RESULTS: Mean volume of the right leg was 1926.64 ± 308.84 ml (mean ± SD). ROI: lower leg: 931.86 ± 236.15 ml; ankle: 201.56 ± 27.88 ml; foot: 793.21 ± 112.28 ml. Mean volume of the left leg was 1937.73 ± 329.51 ml. ROI: lower leg: 933.59 ± 251.12 ml; ankle: 201.53 ± 25.54 ml; foot: 802.62 ± 124.83 ml. There was no significant difference of the overall volume between right and left leg (p > 0.05; overall volume: △ difference: 29.5 ± 7.29 ml, p = 0.8; lower leg: △ difference: 21.5 ± 6.39 ml, p = 0.8; ankle: △ difference: 5.3 ± 2.11 ml, p = 0.4; △ difference: 16.33 ± 4.45 ml, p = 0.8. CONCLUSION: This pilot study defines three regions of interest of the lower leg and demonstrates no difference between the right and left side. Based on these ROI, further studies are needed to evaluate the clinical applicability of the scanner.

Midterm Development of Ultrasound-unstable Hip Joints After Overhead Traction and Treatment With Tübingen Splint and Fettweis Plaster: A Radiologic Follow-up Analysis Over 5.5 Years.

PURPOSE: The aim of this study was to determine the success rate for treatment of ultrasound unstable hips (type D, III and IV) with Fettweis plaster in terms of a midterm follow-up from the very beginning in the neonatal period until the age of 4 to 8 years. METHODS: In total, 69 unstable hips, which were successfully treated with Fettweis plaster and after with a flexion-abduction splint, were included into the study. Hip delvelopment was followed by determining the acetabular index (ACI) on routine pelvic radiographs at the age of 12 to ≤24, 24 to ≤48 and 48 to ≤96 months and the center edge angle on the latter, and classifying both angles according to Tönnis. RESULTS: After initially successful treatment, the first radiograph at the age of 12 to ≤24 months showed 39.1% (n=27) hips with normal findings, 33.2% (n=23) hips with slightly dysplastic findings, and 27.5% (n=19) hips with severe dysplastic findings. Comparison between first and second radiograph showed improvement of the ACI in 9/69 hips and between the second and third time point in 20/69 hips. Overall, 20 hip joints showed deteriorations. Hereby, 16 deteriorations took place after the first radiograph and 4 after the second radiograph. Deteriorations were observed independently of the initial hip type (D, III, and IV). CONCLUSIONS: Midterm results indicate that radiologic controls should be provided to detect deteriorations after finishing treatment. ACI and center edge angle are helpful parameters in the assessment of hip joint development in the age range of 4 to 8 years. LEVEL OF EVIDENCE: Level III.

Volumetry of Hand and Forearm: A 3D Volumetric Approach.

BACKGROUND: Swelling and edema of the hand and forearm may occur in various traumatic and degenerative diseases. So far, no precise measurement protocol exists. The objective of this study was to evaluate an examination protocol with relevant regions of interest (ROIs) measured by a 3-dimensional (3D) scanner to achieve precise, reproducible, and objective measurements for an optimized detection of volumes of the hand and forearm. METHODS: A 3D scan protocol was developed using an Artec, 3D scanner EVA to measure discrete hand volumes of healthy volunteers. Five areas were defined as ROIs, representing volumes of the finger, metacarpus, wrist, hand, and distal forearm. Contralateral limbs were used for volume comparisons and calculation of volume differences. RESULTS: For this study, 12 individuals (58.3% women, 24 hands and forearms) with a mean age of 27.1 ± 3 years were included. Mean volume values for left and right ROIs correlated with each other, with slightly higher volumes for the right upper extremity. Volume differences showed statistically significant results for the finger region (ROI I; P = .009), the metacarpal region (ROI II; P < .001), hand region (ROI IV; P = .001), and forearm region (ROI V; P = .006), with the exception of the wrist region (ROI III; P = .722). CONCLUSIONS: Our results demonstrate that this 3D volumetric approach is a reliable and objective tool for measuring volumes and circumferences in hand and forearm. Based on our determined ROIs, further studies are needed to explore the significance for clinical applications.

UTE-T2* versus conventional T2* mapping to assess posterior cruciate ligament ultrastructure and integrity-an in-situ study.

Background: Clinical-standard morphologic magnetic resonance imaging (MRI) is limited in the refined diagnosis of posterior cruciate ligament (PCL) injuries. Quantitative MRI sequences such as ultrashort echo-time (UTE)-T2* mapping or conventional T2* mapping have been theorized to quantify ligament (ultra-) structure and integrity beyond morphology. This study evaluates their diagnostic potential in identifying and differentiating partial and complete PCL injuries in a standardized graded injury model. Methods: Ten human cadaveric knee joint specimens were imaged on a clinical 3.0 T MRI scanner using morphologic, conventional T2* mapping, and UTE-T2* mapping sequences before and after standardized arthroscopic partial and complete PCL transection. Following manual segmentation, quantitative T2* and underlying texture features (i.e., energy, homogeneity, and variance) were analyzed for each specimen and PCL condition, both for the entire PCL and its subregions. For statistical analysis, Friedman's test followed by Dunn's multiple comparison test was used against the level of significance of P≤0.01. Results: For the entire PCL, T2* was significantly increased as a function of injury when acquired with the UTE-T2* sequence [entire PCL: 11.1±3.1 ms (intact); 10.9±4.6 ms (partial); 14.3±4.9 ms (complete); P<0.001], but not when acquired with the conventional T2* sequence [entire PCL: 10.0±3.2 ms (intact); 11.4±6.2 ms (partial); 15.5±7.8 ms (complete); P=0.046]. The PCL subregions and texture variables showed variable changes indicative of injury-associated disorganization. Conclusions: In contrast to the conventional T2* mapping, UTE-T2* mapping is more receptive in the detection of structural damage of the PCL and allows quantitative assessment of ligament (ultra-)structure and integrity that may help to improve diagnostic differentiation of distinct injury states. Once further substantiated beyond the in-situ setting, UTE-T2* mapping may refine diagnostic evaluation of PCL injuries and -possibly- monitor ligament healing, ageing, degeneration, and inflammation.

Defining the region of interest of the knee for perioperative volumetric assessment with a portable 3D scanner in orthopedic and trauma surgery.

BACKGROUND: The aim of this study was to characterize three regions of interest (ROI) around the knee with a portable 3D scanner (Artec 3D scanner EVA). Soft tissue topography assessment with an optimized, precise, and reproducible method may assist surgeons when managing soft tissue swelling in the post traumatic setting. METHODS: 12 healthy volunteers (24 legs, 7 women, 5 man) were included in this study. The patient cohort showed a mean age of 27.1 years (SD±3), a mean weight of 70 kg (SD±13) and a mean height of 171 cm (SD±8.8). All scans were recorded by the same examiner in the same room and with the same scanner (Artec, 3 D scanner EVA). Three volume regions of interest (ROI) were defined: the distal femur (circumference measured between the of superior extent of the patella to 10 cm proximal), the knee joint (measured from the top of the patella to the tibial tuberosity) and the proximal tibia (tibial tuberosity to 10 cm distal). RESULTS: The mean volume of the right leg was 3.901 l (I. distal femur: 1.63 l, knee joint: 1.33 l, proximal tibia: 1.10 l) and mean volume of the left leg was 3.910 l (I. distal femur: 1.66 l, knee joint: 1.34 l, proximal tibia: 1.12 l). The volume difference between the right and left leg was 0.094 l (SD ± 0.083 l) The Wilcoxon-Mann-Whitney test showed no significant differences of the volumes between the right and left leg. CONCLUSIONS: This study demonstrates that portable 3D scanning could be an accurate and reliable tool for orthopedics and trauma surgeons. Based on the ROIs of this pilot study, further studies are needed to test the significance for clinical applications for patients with an injured knee.

The MRI posterior drawer test to assess posterior cruciate ligament functionality and knee joint laxity.

Clinical Magnetic Resonance Imaging (MRI) of joints is limited to mere morphologic evaluation and fails to directly visualize joint or ligament function. In this controlled laboratory study, we show that knee joint functionality may be quantified in situ and as a function of graded posterior cruciate ligament (PCL)-deficiency by combining MRI and standardized loading. 11 human knee joints underwent MRI under standardized posterior loading in the unloaded and loaded (147 N) configurations and in the intact, partially, and completely PCL-injured conditions. For each specimen, configuration, and condition, 3D joint models were implemented to analyse joint kinematics based on 3D Euclidean vectors and their projections on the Cartesian planes. Manual 2D measurements served as reference. With increasing PCL deficiency, vector projections increased significantly in the anteroposterior dimension under loading and manual measurements demonstrated similar patterns of change. Consequently, if combined with advanced image post-processing, stress MRI is a powerful diagnostic adjunct to evaluate ligament functionality and joint laxity in multiple dimensions and may have a role in differentiating PCL injury patterns, therapeutic decision-making, and treatment monitoring.

Micro- and Macroscale Assessment of Posterior Cruciate Ligament Functionality Based on Advanced MRI Techniques.

T2 mapping assesses tissue ultrastructure and composition, yet the association of imaging features and tissue functionality is oftentimes unclear. This study aimed to elucidate this association for the posterior cruciate ligament (PCL) across the micro- and macroscale and as a function of loading. Ten human cadaveric knee joints were imaged using a clinical 3.0T scanner and high-resolution morphologic and T2 mapping sequences. Emulating the posterior drawer test, the joints were imaged in the unloaded (δ0) and loaded (δ1) configurations. For the entire PCL, its subregions, and its osseous insertion sites, loading-induced changes were parameterized as summary statistics and texture variables, i.e., entropy, homogeneity, contrast, and variance. Histology confirmed structural integrity. Statistical analysis was based on parametric and non-parametric tests. Mean PCL length (37.8 ± 1.8 mm [δ0]; 44.0 ± 1.6 mm [δ1] [p < 0.01]), mean T2 (35.5 ± 2.0 ms [δ0]; 37.9 ± 1.3 ms [δ1] [p = 0.01]), and mean contrast values (4.0 ± 0.6 [δ0]; 4.9 ± 0.9 [δ1] [p = 0.01]) increased significantly under loading. Other texture features or ligamentous, osseous, and meniscal structures remained unaltered. Beyond providing normative T2 values across various scales and configurations, this study suggests that ligaments can be imaged morphologically and functionally based on joint loading and advanced MRI acquisition and post-processing techniques to assess ligament integrity and functionality in variable diagnostic contexts.

CCD angle & hip fractures - Predictor of fracture symmetry?

BACKGROUND: Hip fracture caused by fall is a common injury of the elderly. The risk of sustaining a contralateral hip fracture has been reported to be 5-10%. Aging society heightens the need of efficient prevention tools. To be able to cope with this demand, understanding of biomechanics of hip fractures are mandatory. Previous studies suggest that geometry of the proximal femur could play an important role for fracture probability and fracture type. Thus, analysis of hip geometry could play an important role in the prediction and prevention of bilateral hip fractures. Aim of this study was to elucidate the influence of caput collum diaphyseal angle on the fracture type of proximal femur. MATERIAL AND METHODS: In a retrospective analysis, data of patients with an acute hip fracture who underwent surgical treatment within five years were included. Data was separated into two groups: (I) intra capsular femur fracture (femoral neck fractures) and (II) extra capsular femur fracture (inter- and subtrochanteric femur fractures). Occurrence of a bilateral fracture, age, gender, weight, height and caput collum diaphyseal angle (standardized measurement of the opposite joint on preoperative digital x-rays) of each group were further analyzed. RESULTS: Data of 448 patients were included ((I): 250 vs. (II): 198 patients). Group (I) showed a significant higher mean caput collum diaphyseal angle of 133.9 ± 7.0° (mean ± standard deviation) compared to group (II) with 127.6 ± 6.1° (F (1, 451) = 106.5, p = 0.00). In group (I) 0 patients had a caput collum diaphyseal angle <120° (varus), 214 patients (86%) 120°-140° and 35 patients (14%) angle>140° (valgus). In contrast, in group (II) 21 patients (10%) had a caput collum diaphyseal angle <120° (varus), 175 patients (86%) 120°-140° and 7 patients (4%) >140° (valgus). 52 patients had a bilateral hip fracture. 36 patients (69%) sustained a bilateral hip fracture of the same fracture type. CONCLUSION: Patients with an intra capsular proximal femur fracture showed a significantly higher caput collum diaphyseal angle compared to patients with an extra capsular proximal femur fracture. Moreover, intra capsular femur fractures are correlated with an indifferent (120-140°) or valgus (>140°) femoral neck configuration. Extra capsular femur fractures correlate with an indifferent (120-140°) or varian femoral neck configuration (<120°). The results support the assumption that the caput collum diaphyseal angle has an influence on fracture type of the proximal femur. This could possibly be a predictor for the fracture type of the contralateral hip (second fracture). Based on this, present data may benefit prosthetists in developing new and more efficient hip protectors. LEVEL OF EVIDENCE: Level III. Retrospective comparative study.

The acromiohumeral distance in the MRI should not be used as a decision criterion to assess subacromial space width in shoulders with an intact rotator cuff.

PURPOSE: The acromiohumeral distance is in practice often evaluated on MRI by radiologists and a reduction diagnosed as subacromial impingement. However, the acromiohumeral distance as indicator for a decentered glenohumeral joint is defined on a true AP radiograph with the patient standing or sitting. The present study therefore evaluated the influence of the patient position by comparing the acromiohumeral distance in both modalities in shoulders with an intact rotator cuff. METHODS: On MRI images and true AP radiographs of patients > 20 and < 80 years with an intact rotator cuff the acromiohumeral distance was measured. The maximum cranio-caudal size of the glenoid was measured as a reference to allow a direct comparison of both modalities. RESULTS: Two-hundred and thirty-four shoulders (mean patients age 45.8 ± 14.3 years) were included. The mean acromiohumeral distance/glenoid size ratio of all shoulders was significantly larger (P < 0.0001) on the MRI with 4.6 ± 1.0 in comparison to 4.1 ± 0.9 in the radiographs indicating a smaller acromiohumeral distance on the MRI. In absolute values, a mean acromiohumeral distance of 9.2 mm ± 1.8 on MRI in comparison to 10.4 mm ± 2.4 on the radiographs was calculated. Herewith, the acromiohumeral distance in the MRI was in the average 1.2 mm ± 2.1 (13%) smaller than the in corresponding radiographs (P < 0.0001). CONCLUSION: The acromiohumeral distance is significantly smaller in the MRI in comparison to AP radiographs in shoulders with an intact rotator cuff and should not be used as a decision criterion on MRI to assess glenohumeral centering or subacromial space width. LEVEL OF EVIDENCE: IV.

Treatment of unstable hips with the Tübingen splint in early postnatal period: radiological mid-term results of 75 hips with mean follow-up of 5.5 years.

PURPOSE: For treatment of unstable hips, the Tübingen splint is a treatment option. After the initial treatment, regular radiological follow-up examinations are recommended but there is a lack of long-term outcome studies. Therefore, the further development of unstable hips treated with the Tübingen splint were evaluated. METHODS: From 2004 to 2015 116 patients with 161 unstable hips treated with the Tübingen splint were evaluated. Inclusion criteria were: 1) successfully treated unstable hip (type D, III and IV); 2) pelvic radiographs at the age of one to ≤ two, two to ≤ four and four to ≤ eight years. The acetabular index (ACI) of all and the centre-edge angle (CEA) of the third radiograph were measured and classified according to the Tönnis classification. RESULTS: A total of 53 patients with 75 unstable hips (type D 34 (45.3%), III 33 (44.0%), IV 8 (10.7%)) were included. In comparison of the first, second and third radiograph, an increase of normal findings was seen in 31 (41.3%) to 53 (70.7%) and 60 (80.0%) hips, respectively. However, a decrease of slightly dysplastic hips from 31 (41.3%) to 19 (25.3%) and 14 (18.7%) respectively and severely dysplastic hips from 13 (17.3%) to three (4.0%) and one (1.3%) hip respectively was detected. In comparison of first to second radiograph, 32 hips improved and five hips deteriorated and of second to third radiograph 16 hips improved and six hips deteriorated. The Tönnis classification of ACI compared with CEA showed no significant differences (p = 0.442). CONCLUSION: This study shows a good development of unstable hips treated with the Tübingen splint with mean follow-up 5.5 years. Nevertheless, unexpected deteriorations could be identified. The CEA is an alternative to the ACI. LEVEL OF EVIDENCE: IV.

Histologic examination of the shoulder capsule shows new layer of elastic fibres between synovial and fibrous membrane.

PURPOSE: In the present study, a systematic histological analysis of the glenohumeral joint capsule was conducted. MATERIALS AND METHODS: 12 cadaveric shoulders were examined. Inclusion criteria were: 1) intact joint capsule and 2) fixation in neutral position. The tissue samples were Elastica Hematoxylin-van-Gieson-(ElHvG) stained and diameter, quantity, and distribution patterns were analyzed. RESULTS: We detected a new layer (elastic boundary layer, EBL) between the synovial and fibrous membrane. The elastic fibres of the EBL differ considerably in diameter, quantity, and distribution pattern. CONCLUSIONS: A previously undescribed layer was noticed, which we named elastic boundary layer for now.

Is CT-based cinematic rendering superior to volume rendering technique in the preoperative evaluation of multifragmentary intraarticular lower extremity fractures?

PURPOSE: Cinematic rendering (CR), a recently launched, FDA-approved rendering technique converts CT image datasets into nearly photorealistic 3D reconstructions by using a unique lighting model. The purpose of this study was to compare CR to volume rendering technique (VRT) images in the preoperative visualization of multifragmentary intraarticular lower extremity fractures. METHOD: In this retrospective study, CT datasets of 41 consecutive patients (female: n = 13; male: n = 28; mean age: 52.3 ± 17.9y) with multifragmentary intraarticular lower extremity fractures (calcaneus: n = 16; tibial pilon: n = 19; acetabulum: n = 6) were included. All datasets were acquired using a 128-row dual-source CT. A dedicated workstation was used to reconstruct CR and VRT images which were reviewed independently by two experienced board-certified traumatologists trained in special trauma surgery. Image quality, anatomical accuracy and fracture visualization were assessed on a 6-point-Likert-scale (1 = non-diagnostic; 6=excellent). The regular CT image reconstructions served as reverence standard. For each score, median values between both readers were calculated. Scores of both reconstruction methods were compared using a Wilcoxon-Ranksum test with p < 0.05 indicating statistical significance. Inter-reader agreement was calculated using Spearman's rank correlation coefficient. RESULTS: Compared to VRT, CR demonstrated a higher image quality (VRT:2.5; CR:6.0; p < 0.001), a higher anatomical accuracy (VRT:3.5; CR:5.5; p < 0.001) and provided a more detailed visualization of the fracture (VRT:2.5; CR:6.0; p < 0.001). An additional benefit of CR reconstructions compared to VRT reconstructions was reported by both readers in 65.9 % (27/41) of all patients. CONCLUSIONS: CR reconstructions are superior to VRT due to higher image quality and higher anatomical accuracy. Traumatologists find CR reconstructions to improve visualization of lower extremity fractures which should thus be used for fracture demonstration during interdisciplinary conferences.

Doctor, when can I drive? - Range of functional ankle motion during driving.

BACKGROUND: Driving a motor vehicle needs a specific joint mobility and yet only limited knowledge exists regarding the necessary ankle range of motion. The goal of this study is to characterize the sequence and range of ankle motion. METHODS: The arc of plantarflexion/dorsiflexion and supination/pronation was recorded in the right and left ankle using electrogoniometers while thirty laps were driven by fifteen healthy participants around a course in a manual transmission car with a left sided steering wheel. The driver was required to perform the following maneuvers during each lap: (I) Vehicle acceleration and gear change, (II) Sudden evasion, (III) Routine turning, (IV) Rapid turning, (V) Vehicle acceleration followed by emergency braking. RESULTS: Driving required the right ankle to plantarflex 13±9 and dorsiflex 22±7 while supinating 15±7 degrees and pronating minimally. The left ankle plantarflexed 19±10and dorsiflexed 17±10 while supinating 15±7 degrees and pronating minimally. The right ankle dorsiflexed significantly more (p=0.00), and yet the left ankle had a significantly higher maximum plantarflexion and range of plantarflexion/dorsiflexion (p=0.00). Emergency braking resulted in a significantly higher maximum plantarflexion as well as plantarflexion/dorsiflexion range when compared to other maneuvers. CONCLUSION: This study describes the range of ankle motion identified to drive a car with a manual transmission and a left-sided steering wheel. The right and left ankle exhibit different arcs of motion during driving. This knowledge may assist when evaluating a patient's driving capability. Further studies are needed to investigate whether movement restrictions impair driving. LEVEL OF EVIDENCE: Basic science study.

Impact of different metal artifact reduction techniques on attenuation correction in 18F-FDG PET/CT examinations.

OBJECTIVE: To evaluate the impact of different metal artifact reduction (MAR) algorithms on Hounsfield unit (HU) and standardized uptake values (SUV) in a phantom setting and verify these results in patients with metallic implants undergoing oncological PET/CT examinations. METHODS AND MATERIALS: In this prospective study, PET-CT examinations of 28 oncological patients (14 female, 14 male, mean age 69.5 ± 15.2y) with 38 different metal implants were included. CT datasets were reconstructed using standard weighted filtered back projection (WFBP) without MAR, MAR in image space (MARIS) and iterative MAR (iMAR, hip algorithm). The three datasets were used for PET attenuation correction. SUV and HU measurements were performed at the site of the most prominent bright and dark band artifacts. Differences between HU and SUV values across the different reconstructions were compared using paired t-tests. Bonferroni correction was used to prevent alpha-error accumulation (p < 0.017). RESULTS: For bright band artifacts, MARIS led to a non-significant mean decrease of 12.0% (345 ± 315 HU) in comparison with WFBP (391 ± 293 HU), whereas iMAR led to a significant decrease of 68.3% (125 ± 185 HU, p < 0.017). For SUVmean, MARIS showed no significant effect in comparison with WFBP (WFBP: 0.99 ± 0.40, MARIS: 0.96 ± 0.39), while iMAR led to a significant decrease of 11.1% (0.88 ± 0.35, p < 0.017). Similar results were observed for dark band artifacts. CONCLUSION: iMAR significantly reduces artifacts caused by metal implants in CT and thus leads to a significant change of SUV measurements in bright and dark band artifacts compared with WFBP and MARIS, thus probably improving PET quantification. ADVANCES IN KNOWLEDGE: The present work indicates that MAR algorithms such as iMAR algorithm in integrated PET/CT scanners are useful to improve CT image quality as well as PET quantification in the evaluation of tracer uptake adjacent to large metal implants. A detailed analysis of oncological patients with various large metal implants using different MAR algorithms in PET/CT has not been conducted yet.

MRI-biochemical follow up measurements of lumbar intervertebral disc in patients with leg length discrepancy: Is it possible to alter cartilage damage with conservative therapy?

OBJECTIVE: Effect of conservative therapy on intervertebral discs (IVD) in patients with leg-length-discrepancy (LLD). M&M: Seventy lumbar IVDs of 14 participants (five with LLD 10-20 mm) were examined using a 3T-MRI-scanner. Morphological (Pfirrmann) and molecular (glycosaminoglycan-chemical-exchange-saturation-transfer, gagCEST) grading was assessed before and after a four-month therapy (physiotherapy and shoe inlays). RESULTS: Significantly lower GAG values in patients with LLD were found (L5/S1, p = 0.02). After therapy, a trend towards higher gagCEST values in patients with LLD was observed (2.48 ±â€¯1.77% vs. 1.79 ±â€¯0.79%; p > 0.05). CONCLUSION: LLD represents a risk factor for molecular alterations of lumbar IVDs. Only minor effects of conservative therapy on these alterations could be found.

Human iPSC-derived iMSCs improve bone regeneration in mini-pigs.

Autologous bone marrow concentrate (BMC) and mesenchymal stem cells (MSCs) have beneficial effects on the healing of bone defects. To address the shortcomings associated with the use of primary MSCs, induced pluripotent stem cell (iPSC)-derived MSCs (iMSCs) have been proposed as an alternative. The aim of this study was to investigate the bone regeneration potential of human iMSCs combined with calcium phosphate granules (CPG) in critical-size defects in the proximal tibias of mini-pigs in the early phase of bone healing compared to that of a previously reported autograft treatment and treatment with a composite made of either a combination of autologous BMC and CPG or CPG alone. iMSCs were derived from iPSCs originating from human fetal foreskin fibroblasts (HFFs). They were able to differentiate into osteoblasts in vitro, express a plethora of bone morphogenic proteins (BMPs) and secrete paracrine signaling-associated cytokines such as PDGF-AA and osteopontin. Radiologically and histomorphometrically, HFF-iMSC + CPG transplantation resulted in significantly better osseous consolidation than the transplantation of CPG alone and produced no significantly different outcomes compared to the transplantation of autologous BMC + CPG after 6 weeks. The results of this translational study imply that iMSCs represent a valuable future treatment option for load-bearing bone defects in humans.

Normal CRP and WBC values in total hip arthroplasty (THA) with signs of loosening. Do we need a joint aspiration?

PURPOSE: Overall Total hip arthroplasty (THA) is a very successful procedure. However, in case of complication dedicated management is required. Two major complications of THA failures are aseptic loosening (AL) and periprosthetic joint infection (PJI). The primary hypothesis of this study was that joint aspirations in patients with signs of loosening after THA are capable to detect PJI in suspected AL with negative serologic testing. METHODS: In this study a total of 108 symptomatic patients with radiographic signs of prosthetic loosening and hip pain in THA were included. Based on a standardized algorithm all patients underwent serological testing followed by joint aspiration preoperatively. Intraoperatively harvested samples were subjected to microbiological testing and served as the gold standard in differential diagnosis. Demographics, as well as the results of serologic and microbiological testing were collected from the medical records. RESULTS: Of the included patients 85 were finally diagnosed with an AL and 23 with PJI. Within the patients with PJI 13 (56%) patients demonstrated elevated CRP and WBC counts, as well as positive synovial cultures after joint aspiration. In ten patients (44%) diagnosed with PJI neither CRP nor WBC were abnormal. CONCLUSION: The diagnosis of PJI can be difficult in THA with radiographic signs of loosening. Clinical features including pain, fever, and local sings of infection are uncommon especially a long period after index operation. First-line screening testing relies on serological evaluation of CRP and WBC. However, normal CRP and WBC values cannot rule out a PJI. These cases can be detected by joint aspiration and synovial cultures reliably.

Aseptic Loosening after THA and TKA - Do gender, tobacco use and BMI have an impact on implant survival time?

PURPOSE: Aseptic loosening (AL) has been reported to be one of the most frequent complications in Total Knee Arthroplasty (TKA) and Total Hip Arthroplasty (THA). The aim of this study was to identify the effects of gender, current tobacco use and BMI on the incidence of AL and implant survival time in THA and TKA. METHODS: Between July 2012 and December 2016 all patients that were diagnosed with an AL of a primary THA or primary TKA and underwent revision surgery at a single institution were retrospectively reviewed for this study. For each patient gender, current tobacco use, BMI, and implant survival time were obtained from the medical records. RESULTS: 202 patients with 85 THA and 117 TKA were included in this study. There was no impact of the gender on implant survival times (p > 0.05) in THA and TKA. In the TKA group current tobacco use was associated with a significant shorter implant survival time (p < 0.05). For THA and TKA with cemented stem fixation a significant increase of AL was seen in overweight compared to normal weight patients (p < 0.05) and in obese compared to normal weight patients (p < 0.05). CONCLUSION: The results demonstrate that current tobacco use and elevated BMI are associated with increased rates of AL in TKA. Also, in THA with cemented stem fixation an elevated BMI is associated with an increased incidence of AL.

Assessment of glycosaminoglycan content in intervertebral discs of patients with leg length discrepancy: A pilot study.

OBJECTIVE: Leg length discrepancy (LLD) could be a predisposing factor for early degeneration of lumbar intervertebral discs (IVD). The purpose of this study was to elucidate the molecular effect of LLD on IVDs. METHODS: IVDs of Eleven patients (25.6 ±â€¯4.3years) with LLD (>10 mm) and 14 control subjects (23.9 ±â€¯3.5years) were compared using a 3T-MR scanner. Morphological T2-weighted and glycosaminoglycan-chemical-exchange-saturation-transfer (gagCEST) sequences were performed. RESULTS: No differences in morphological Pfirrmann grading were found (p > 0.05). In contrast, nucleus-pulposus-gagCEST-values of L5/S1 were significantly lower (p = 0.0008). CONCLUSION: Our results suggest that LLD is a predisposing factor for molecular IVD alterations, which are detectable even before morphological pathologies could be found.