Repeated Ct-based Hounsfield Unit Measurements as a Proxy Measure of Intercorporal Bone Graft Remodelling Towards Spinal Fusion; a Feasibility Study.

Background: There is a lack of knowledge about the biological process of intercorporal bone graft remodelling towards successful lumbar spine fusion with bridging vital bone between two adjacent vertebrae. Hounsfield Units (HU) highly correlate with Bone Mineral Density (BMD) and changes in HU may be valuable as proxy measure to monitor ongoing fusion. The aims of this study were to explore the feasibility to quantify BMD changes in the intercorporal bone graft after spinal fusion on consecutive CT-scans, and to explore whether trends in the individual changes in HU over time may serve as a proxy measure for successful fusion or non-fusion.Methods: A retrospective case series was conducted using available one-year and two-year CT-data from patients after posterior lumbar interbody fusion surgery. First, a standardized measuring procedure was developed, incorporating internal phantomless calibration, to establish the HU values of the grafted region of interest using consecutive CT-slices. Subsequently, changes in the participants’ bone graft HU over time between their first and second year after surgery were explored.Results: Between one and two years after surgery, seven out of nine (78%) participants showed an increase in their bone grafts’ HU, ranging from 3% to 41%. In two participants HU-values decreased 14% and 32%, respectively. The intraobserver reliability of the HU measuring procedure was excellent (ICC 0.93 (95% confidence interval 0.91 to 0.95)).Conclusion: The majority (78%) of participants in the current study showed increases in their bone graft HU, which suggests ongoing bone graft remodelling towards lumbar fusion. This result corresponds with the established percentages of achieved rigid bony fusion after lumbar spinal fusion surgery reported in the literature. Thus, prospective follow-up of CT-based HU measurements may have potential as diagnostic measure to monitor bone graft remodelling in time and trends may predict successful fusion or non-fusion. The measurement procedure developed in this study, using internal phantomless calibration, showed excellent intraobserver reliability and merits further study in larger patient numbers.

Inter- and intraobserver reliability of morphological Mutch classification for greater tuberosity fractures of the proximal humerus: A comparison of x-ray, two-, and three-dimensional CT imaging

Background The objective of this study was to investigate inter- and intraobserver reliability of the morphological Mutch classification for greater tuberosity (GT) fragments in consecutive proximal humerus fractures (PHF) regardless of the number of parts according to the Codman classification system for three different imaging modalities (plain radiographs, two-dimensional [2-D] computed tomography [CT], and reformatted, three-dimensional [3-D] CT reconstruction). Materials and methods One hundred thirty-eight consecutive PHF with GT involvement were identified between January 2018 and December 2018 in a supraregional Level 1 trauma center. GT morphology was classified by three blinded observers according to the morphological Mutch classification using the picture archiving and communication software Visage 7.1 (Visage Imaging Inc., San Diego, CA, USA). Fleiss’ and Cohens’ kappa were assessed for inter- and intraobserver reliability. Strength of agreement for kappa (k) values was interpreted according to the Landis and Koch benchmark scale. Results In cases of isolated GT fractures (n = 24), the morphological Mutch classification achieved consistently substantial values for interobserver reliability (radiograph: k = 0.63; 2-D CT: k = 0.75; 3-D CT: k = 0.77). Moreover, use of advanced imaging (2-D and 3-D CT) tends to increase reliability. Consistently substantial mean values were found for intraobserver agreement (radiograph: Ø k = 0.72; 2-D CT: Ø k = 0.8; 3-D CT: Ø k = 0.76). In cases of multi-part PHF with GT involvement (n = 114), interobserver agreement was only slight to fair regardless of imaging modality (radiograph: k = 0.3; 2-D CT: k = 0.17; 3-D CT: k = 0.05). Intraobserver agreement achieved fair to moderate mean values (radiograph: Ø k = 0.56; 2-D CT: Ø k = 0.61; 3-D CT: Ø k = 0.33). Conclusion The morphological Mutch classification remains a reliable classification for isolated GT fractures, even with 2-D or 3-D CT imaging. Usage of these advanced imaging modalities tends to increase interobserver reliability. However, its reliability for multi-part fractures with GT involvement is limited. A simple and reliable classification is missing for this fracture entity.

“Double-Pulley” Dual-Row Technique for Arthroscopic Fixation of Large Bony Bankart Lesion: Minimum 2-Year Follow-up With CT Evaluation

Background: A “double-pulley” dual-row technique had been applied for arthroscopic fixation of large bony Bankart lesion in which the fragment has a wide base. Purpose: To investigate clinical outcomes and glenoid healing after arthroscopic fixation of bony Bankart lesion using the double-pulley dual-row technique. Study Design: Case series; Level of evidence, 4. Methods: A total of 25 patients were included in this retrospective study. The American Shoulder and Elbow Surgeons (ASES) score, pain visual analog scale (VAS) score, and range of motion of the affected shoulder were assessed. Radiographs and computed tomography (CT) scans (preoperatively, immediately after surgery, and at 1 year postoperatively) were performed to evaluate arthritic changes (Samilson-Prieto classification) and glenoid size. The intraobserver reliability of the CT measurements was analyzed. Results: At a mean follow-up of 3.4 years, the mean ASES and VAS scores were 94.87 ± 5.02 and 0.48 ± 0.59, respectively. Active forward elevation, external rotation with the arm at the side, and internal rotation were 165.80° ± 11.70°, 33.20° ± 8.02°, and T9 (range, T6-S1), respectively. No patient reported a history of redislocation or instability. The intraobserver reliability of the CT measurements was moderate to excellent. The mean preoperative size of the bony fragment was measured as 23.4% ± 7.8% of the glenoid articular surface. The quality of the reduction was judged to be excellent in 13 (52%) cases, good in 8 (32%), and fair in 4 (16%). The mean immediate postoperative glenoid size was 96.8% ± 4.3%, and bone union was found in all cases. There were no significant differences between reconstructed and immediate postoperative glenoid size or between preoperative and final Samilson-Prieto grades. Conclusion: The arthroscopic double-pulley method was a reliable technique for the fixation of large bony Bankart lesions with a wide base. Satisfactory results can be expected regarding the restoration of the glenoid morphology and stability of the shoulder. High healing rate and good shoulder function can be achieved. No radiological evidence of cartilage damage caused by suture abrasion was found at 2- to 5-year follow-up.

Interobserver reliability is higher for assessments with 3D software-generated models than with conventional MRI images in the classification of trochlear dysplasia

Purpose Trochlear dysplasia is a significant risk factor for patellofemoral instability. The severity of trochlear dysplasia is commonly evaluated based on the Dejour classification in axial MRI slices. However, this often leads to heterogeneous assessments. A software to generate MRI-based 3D models of the knee was developed to ensure more standardized visualization of knee structures. The purpose of this study was to assess the intra- and interobserver agreements of 2D axial MRI slices and an MRI-based 3D software generated model in classification of trochlear dysplasia as described by Dejour. Methods Four investigators independently assessed 38 axial MRI scans for trochlear dysplasia. Analysis was made according to Dejour’s 4 grade classification as well as differentiating between 2 grades: low-grade (types A + B) and high-grade trochlear dysplasia (types C + D). Assessments were repeated following a one-week interval. The inter- and intraobserver agreement was determined using Cohen’s kappa (κ) and Fleiss kappa statistic (κ). In addition, the proportion of observed agreement (po) was calculated for assessment of intraobserver agreement. Results The assessment of the intraobserver reliability with regard to the Dejour-classification showed moderate agreement values both in the 2D (κ = 0.59 ± 0.08 SD) and in the 3D analysis (κ = 0.57 ± 0.08 SD). Considering the 2-grade classification, the 2D (κ = 0.62 ± 0.12 SD) and 3D analysis (κ = 0.61 ± 0.19 SD) each showed good intraobserver matches. The analysis of the interobserver reliability also showed moderate agreement values with differences in the subgroups (2D vs. 3D). The 2D evaluation showed correspondences of κ = 0.48 (Dejour) and κ = 0.46 (high / low). In the assessment based on the 3D models, correspondence values of κ = 0.53 (Dejour) and κ = 0.59 (high / low) were documented. Conclusion Overall, moderate-to-good agreement values were found in all groups. The analysis of the intraobserver reliability showed no relevant differences between 2 and 3D representation, but better agreement values were found in the 2-degree classification. In the analysis of interobserver reliability, better agreement values were found in the 3D compared to the 2D representation. The clinical relevance of this study lies in the superiority of the 3D representation in the assessment of trochlear dysplasia, which is relevant for future analytical procedures as well as surgical planning. Level of evidence Level II.

Association Between 45° Flexion Anteroposterior Elbow Radiographs and Diagnostic Accuracy of Capitellum Osteochondritis Dissecans

Background: An anteroposterior (AP) radiograph of the elbow in 45° of flexion has been suggested to increase the diagnostic accuracy of capitellum osteochondritis dissecans (OCD). Purpose: To assess the diagnostic performance, inter- and intraobserver reliability, and confidence level for identifying capitellum OCD using plain radiographs (AP, lateral, and 45° flexion AP). Study Design: Cohort study (Diagnosis); Level of evidence, 3. Methods: This was a retrospective study of pediatric and adolescent patients with capitellum OCD and a control group. Six independent clinicians who were blinded to the official radiologists’ reports reviewed images on 2 separate occasions, 1 week apart. A 5-point Likert scale was used to assess the clinicians’ level of confidence. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated for individual and combinations of radiographic views. Inter- and intraobserver reliability was determined using Cohen kappa (κ) coefficients. Results: A total of 28 elbows (mean age, 12.5 ± 2 years) were included. There were no differences in age ( P = .18), sex ( P = .62), or laterality ( P > .999) between groups. There were marked variations in the diagnostic accuracy between views: sensitivity (AP, 85.1; lateral, 73.2; 45° flexion AP, 91.7), specificity (AP, 89.3; lateral, 91.7; 45° flexion AP, 91.1), PPV (AP, 88.8; lateral, 89.8; 45° flexion AP, 91.1), NPV (AP, 85.7; lateral, 77.4; 45° flexion AP, 91.6), and accuracy (AP, 87.2; lateral, 82.4; 45° flexion AP, 91.4). Standard radiographs (AP and lateral views) failed to diagnose capitellum OCD in 4.8% of cases. The sensitivity of the 3 combined views was 100%. Confidence intervals in the clinicians’ diagnostic assessments were similar for each view (AP, 4.0; lateral, 4.0; and 45° flexion AP, 4.1). Interobserver reliability was substantial for AP and lateral views (κ = 0.65 and κ = 0.60, respectively) but highest for the 45° flexion AP radiographs (κ = 0.72). Intraobserver reliability for the 45° flexion AP view was moderate to almost perfect (κ = 0.45 to 0.93). Conclusion: The 45° flexion AP view can detect capitellum OCD with excellent accuracy, a high level of confidence, and substantial interobserver agreement. When added to standard AP and lateral radiographs, the 45° flexion AP view aids in the identification of capitellum OCD.

P–319 Measuring intraobserver and intermethod reliability of endometriotic cyst volumes: a comparison between MRI and 3D transvaginal ultrasound

Study question Are three-dimensional imaging techniques, MRI and three-dimensional transvaginal ultrasound reliable for the volume measurement of endometriotic cysts? Summary answer MRI and XI VOCAL 3D-transvaginal ultrasound both provide a very good intraobserver reliability. The imaging techniques are however not advised to be used interchangeably. What is known already Two-dimensional transvaginal ultrasound (2D-TVUS) and MRI are commonly used in endometriosis care. However, three-dimensional ultrasound (3D-US) has gained more attention in recent years. The use of 3D-US, more specifically VOCAL and XI VOCAL software has proven to be a reliable tool in the measurement of volumes such as splenic volumes and uterine niche volumes. Up to date, 3D-TVUS has not been evaluated for volume measurements in endometrioma. Study design, size, duration A prospective case-control study was performed in an academic endometriosis centre. In total, 23 endometriosis cysts from 16 patients were included. Participants/materials, setting, methods Women diagnosed with endometriosis through laparoscopy with histological confirmation presenting with uni- or bilateral endometrioma on TVUS were included in this study. All women had a regular menstrual cycle (28 days ± 3 days). Women were seen for examinations at two time points during one menstrual cycle: on cycle day 2–4 (T0) and cycle day 20–22 (T1). At both time points a 2D and 3D TVUS and an MRI at 1,5T were performed. Main results and the role of chance The intraclass correlation for intraobserver reliability is good to very good for all three techniques ranging from the lowest value of 0.953 to the highest of 1.000. MRI has the most narrow limits of agreement (–3.93 to 4.53), followed by XI VOCAL (–5.16 – 5.65) while VOCAL has the widest limits of agreement (–10.22 to 11.39). Intraclass correlations are poor in the comparison of XI VOCAL to MRI, moderate between VOCAL and XI VOCAL, and good for the comparison between VOCAL and MRI. The limits of agreement are widest for XI VOCAL versus MRI (–36.96 –10.54). Similar limits of agreement are found between VOCAL versus XI VOCAL (–7.80 –23.40) as between VOCAL versus MRI (–18.27–8.96). Limitations, reasons for caution No absolute volume measurements were obtained during subsequent surgery to compare the imaging data to. This makes it more difficult to determine an acceptable error margin for the 3D imaging techniques used. Wider implications of the findings: Being able to determine (small) volumetric changes in endometrioma can give more insight into the development and circumstances under which endometrioma grow or decrease in size. For reliable and accurate follow up of endometrioma a single measuring technique must be used as three-dimensional imaging techniques are not interchangeable. Trial registration number Trial NL2106 (NTR2223)