Minimial clinically important difference values in distal metaphyseal ulnar shortening for ulnar impaction syndrome and assessment of the relationship between level of the osteotomy and bone union time.

OBJECTIVE: We aimed to define minimal clinically important difference (MCID) values of patient-reported outcome measures (PROMs) for distal metaphyseal ulnar shortening and to assess the relationship between level of the osteotomy and time to bone union. METHODS: 20 patients who had distal metaphyseal ulnar shortening osteotomies due to ulnar impaction syndrome and had at least 6 months of follow-ups were included in this study. The mean follow-up period was 12.3 ± 7.01 months. The PROMs which consisted of patient-rated wrist evaluation (PRWE) and quick disabilities of arm, shoulder, and hand (QDASH) were recorded on the day before the surgery and at follow-up assessments. Grip strength and range of motion were recorded for operated and contralateral wrists at postoperative assessments. Postoperative radiological evaluations of distance of the osteotomy from the distal ulnar articular surface (osteotomy level), the union of osteotomy site; preoperative and postoperative evaluations of styloid-triquetral distance, and ulnar variance were performed using AP wrist x-rays. The MCID values for PRWE and QDASH were calculated using ROC curve analysis. RESULTS: Mean PRWE and QDASH scores decreased statistically significantly. The mean grip strength of contralateral wrists was higher. Mean ulnar variance decreased, whereas styloid-triquetral distance increased postoperatively. Patients with osteotomy levels of greater than 13.7 mm had a longer time from surgery to bone union. Furthermore, patients with time from surgery to bone union shorter than 7 weeks had an osteotomy closer to the ulnar articular surface. The MCID values for PRWE and QDASH were analyzed and calculated through the ROC curve as 22.25 and 20.45, respectively. CONCLUSION: This study has shown us that the osteotomy level affects the time to bone union and an osteotomy closer than 13.7 mm to the ulnar articular surface seems to result in shorter union time. Furthermore, MCID values were defined for PRWE and QDASH as 22.25 and 20.45, respectively. LEVEL OF EVIDENCE: Level IV, Therapeutic Study.

An Automated TW3-RUS Bone Age Assessment Method with Ordinal Regression-Based Determination of Skeletal Maturity.

The assessment of bone age is important for evaluating child development, optimizing the treatment for endocrine diseases, etc. And the well-known Tanner-Whitehouse (TW) clinical method improves the quantitative description of skeletal development based on setting up a series of distinguishable stages for each bone individually. However, the assessment is affected by rater variability, which makes the assessment result not reliable enough in clinical practice. The main goal of this work is to achieve a reliable and accurate skeletal maturity determination by proposing an automated bone age assessment method called PEARLS, which is based on the TW3-RUS system (analysis of the radius, ulna, phalanges, and metacarpal bones). The proposed method comprises the point estimation of anchor (PEA) module for accurately localizing specific bones, the ranking learning (RL) module for producing a continuous stage representation of each bone by encoding the ordinal relationship between stage labels into the learning process, and the scoring (S) module for outputting the bone age directly based on two standard transform curves. The development of each module in PEARLS is based on different datasets. Finally, corresponding results are presented to evaluate the system performance in localizing specific bones, determining the skeletal maturity stage, and assessing the bone age. The mean average precision of point estimation is 86.29%, the average stage determination precision is 97.33% overall bones, and the average bone age assessment accuracy is 96.8% within 1 year for the female and male cohorts.

Ulnar shortening osteotomy for posttraumatic ulnar impaction syndrome in adolescent (younger than 18 years) - Based on the Cha & Shin assessment.

PURPOSE: We performed ordinary ulnar shortening osteotomy (USO) in patients younger than 18 years old with secondary ulnar impaction syndrome (UIS) after traumatic events. Here, we report the clinical and radiologic outcomes with a review of the previous literature through a retrospective case series. METHODS: Twenty-two adolescents treated by USOs from 2006 to 2018 were investigated. The amount of shortening was classified into three categories. The first category was for a still open physis on the medial half of the radius in those younger than 15. In this category, we osteotomized the ulna for the physis level to be left neutral or negative by 1-2 mm. The second category had no growth potency in the radius. If the patient was younger than 15, we considered only residual growth of the ulna, thus performing USO for the ordinary UV to be negative by 2-3 mm. For patients aged 15-18 years old, if growth potency was nearly absent in the ulna, we performed traditional USO with a neutral ulnar variance (UV). RESULTS: Categories 1, 2, and 3 for the amount of USO were determined for 4, 4, and 14 patients, respectively. All USOs properly healed without substantial complications. The mean preoperative UV was 2.91 mm, and the final value decreased to 0.23 with statistical significance (p < 0.001). The range of wrist motion was improved after USO from 133.86° and 132.73° to 154.77° and 160.68° (all, p < 0.001 in flexion-extension and pronation-supination arcs, respectively). The preoperative VAS and MMWS scores also improved from 2.77 to 75.00 to 0.18 and 88.86, respectively, at the final follow-up (all, p < 0.001). CONCLUSIONS: UIS in adolescent populations after trauma in their children/younger adolescents could be properly treated by USO. Even with an open physis at the ulna, neutral UVs could be achieved, and the clinical outcomes were satisfactory. However, long-term follow-up is still needed regarding TFCC and DRUJ status. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Ulnar variance in distal radial fractures: assessment and interpretation.

We explored patterns of shortening of the distal radius and investigated the effect of displacement on 'ulnar variance' in 250 patients with distal radial fractures. A small number of patients (5%) had a fracture that resulted in true shortening. Thirty-two per cent had fractures that appeared short, but lateral radiographs revealed that the articular surface was tilted, with either the anterior or dorsal rim of the articular surface being proximal to the distal ulna but the other rim was distal to it. We recommend initial assessment of variance on lateral radiographs. If the anterior and dorsal rims of the distal radial articular surface are proximal to the distal ulna, then true shortening is present and lengthening and stabilization, to hold the radius distracted, should be considered. If only one rim is proximal to the distal ulna, then correction of the tilt will lessen the apparent positive variance.Level of evidence: IV.

Does the Use of Sanders Staging and Distal Radius and Ulna Classification Avoid Mismatches in Growth Assessment with Risser Staging Alone?

BACKGROUND: Although Risser stages are visible on the same radiograph of the spine, Risser staging is criticized for its insensitivity in estimating the remaining growth potential and its weak correlation with curve progression in patients with adolescent idiopathic scoliosis. Risser staging is frequently accompanied by other skeletal maturity indices to increase its precision for assessing pubertal growth. However, it remains unknown whether there is any discrepancy between various maturity parameters and the extent of this discrepancy when these indices are used concurrently to assess pubertal growth landmarks, which are important for the timing of brace initiation and weaning. QUESTIONS/PURPOSES: (1) What is the chronologic order of skeletal maturity grades based on the growth rate and curve progression rate in patients with adolescent idiopathic scoliosis? (2) What are the discrepancies among the grades of each maturity index for indicating the peak growth and start of the growth plateau, and how do these indices correspond to each other? (3) What is the effectiveness of Risser staging, Sanders staging, and the distal radius and ulna classification in assessing peak growth and the beginning of the growth plateau? METHODS: Between 2014 and 2017, a total of 13,536 patients diagnosed with adolescent idiopathic scoliosis were treated at our tertiary clinic. Of those, 3864 patients with a radiograph of the left hand and wrist and a posteroanterior radiograph of the spine at the same visits including initial presentation were considered potentially eligible for this study. Minimum follow-up was defined as 6 months from the first visit, and the follow-up duration was defined as 2 years since initial consultation. In all, 48% (1867 of 3864) of patients were eligible, of which 26% (485 of 1867) were excluded because they were prescribed bracing at the first consultation. These patients visited the subsequent clinics wearing the brace, which might have affected body height measurement. Six percent (117 of 1867) of eligible patients were also excluded as their major coronal Cobb angle reached the surgical threshold of 50° and had undergone surgery before skeletal maturity. Another 21% (387 of 1867) of patients were lost before minimum follow-up or had incomplete data, leaving 47% (878) for analysis. These 878 patients with 1139 skeletal maturity assessments were studied; 74% (648 of 878) were girls. Standing body height was measured in a standardized manner by a wall-mounted stadiometer. Several surgeons measured curve magnitude as per routine clinical consultation, skeletal maturity was measured according to the distal radius and ulna classification, and two raters measured Risser and Sanders stages. Reliability tests were performed with satisfaction. Data were collected for the included patients at multiple points when skeletal maturity was assessed, and only up to when brace wear started for those who eventually had bracing. The growth rate and curve progression rate were calculated by the change of body height and major coronal Cobb angle over the number of months elapsed between the initial visit and next follow-up. At each skeletal maturity grading, we examined the growth rate (in centimeters per month) and curve progression rate (in degrees per month) since the skeletal maturity assessment, as well as the mean age at which this maturity grading occurred. Each patient was then individually assessed for whether he or she was experiencing peak growth and the beginning of growth plateau at each timepoint by comparing the calculated growth rate with the previously defined peak growth rate of ≥ 0.7 cm per month and the beginning of growth plateau rate of ≤ 0.15 cm per month in this adolescent idiopathic scoliosis population. Among the timepoints at which the peak growth and the beginning of growth plateau occurred, the median maturity grade of each maturity index was identified as the benchmark grade for comparison between indices. We used the McNemar test to investigate whether pubertal growth landmarks were identified by specific maturity grades concurrently. We assessed the effectiveness of these skeletal maturity indices by the difference in proportions (%) between two benchmark grades in indicating peak growth and the growth plateau. RESULTS: For girls, the chronological order of maturity grades that indicated peak growth was the radius grade, ulna grade, Sanders stage, and Risser stage. Curve progression peaked between the age of 11.6 and 12.1 years at a similar timing by all maturity indices for girls but was inconsistent for boys. For both sexes, radius (R) grade 6, ulna (U) grade 5, Sanders stage (SS) 3, and Risser stage 0+ were the median grades for peak growth, whereas Risser stage 4, R8/9, U7/8, and SS6/7 indicated the beginning of the growth plateau. The largest discrepancy between maturity indices was represented by Risser stage 0+, which corresponded to six grades of the Sanders staging system (SS2 to SS7) and to R6 in only 41% (62 of 152) of girls in the whole cohort. Despite Risser stage 0+ corresponding to the wide range of Sanders and distal radius and ulna grades, none of the R6, U5, SS3, and Risser stage 0+ was found more effective than another grade in indicating the peak growth in girls. R6 most effectively indicated the peak growth in boys, and Risser stage 0+ was the least effective. For the beginning of the growth plateau in girls, SS6/7 was the most effective indicator, followed by U7/8. Risser stage 4 was the least effective because it indicated 29% (95% CI 21% to 36%; p < 0.001) fewer patients who reached the beginning of the growth plateau than did those with R8/9. Risser stage 4 also indicated 36% (95% CI 28% to 43%; p < 0.001) fewer patients who reached the beginning of the growth plateau than those indicated by U7/8, and it identified 39% fewer patients than SS6/7 (95% CI 32% to 47%; p < 0.001). For boys, similarly, R8/9, U7/8, and SS6/7 were all more effective than Risser stage 4 in identifying when the growth plateau began. CONCLUSION: Risser stage 0+ corresponds to a wide range of Sanders and distal radius and ulna grades. Risser stage 0+ is least effective in indicating the peak growth in boys, and Risser stage 4 is the least effective maturity grade for indicating when the growth plateau starts in both sexes. The concurrent use of R6 and SS3 can be useful for detecting the peak growth, and SS6/7 in conjunction with U7/8 is most effective in indicating the beginning of the growth plateau. Using a combination of specific grades of Sanders staging and the distal radius and ulna classification can indicate pubertal growth landmarks with reduced risk of underestimating or overestimating skeletal maturity. These findings may aid in refining clinical decision-making of brace initiation and weaning at a more precise timing. Among Risser stage 0, the appearance of R6, U5, and SS3 provide the most effective assessment of peak growth that can indicate the most effective bracing period within which curve progression occurs. For initiation of the growth plateau, Risser 4 is not useful, and SS6/7, R8/9 and U7/8 should be used instead. LEVEL OF EVIDENCE: Level III, diagnostic study.

Wrist-Spanning Fixation of Radiocarpal Dislocation: A Cadaveric Assessment of Ulnar Translation.

Background: Radiocarpal dislocations represent a high-energy wrist injury that can occur with or without concomitant fractures about the wrist. Poor outcomes are often due to radiocarpal instability and secondary ulnar translation. The purpose of this cadaveric study is to determine if there is any difference in the radiographic parameters in a wrist dislocation model given the different location of distal fixation. Methods: Ten paired fresh cadaver upper extremities were fluoroscopically evaluated with posterior-anterior (PA) and lateral views. We created a radiocarpal dislocation model and applied a dorsal bridge plate to either the second or third metacarpal. Repeat PA and lateral fluoroscopic views were obtained for evaluation of radial inclination, radial height, volar tilt, ulnar variance, radiolunate angle, radioscaphoid angle, scapholunate angle, radial rotation index, and four indices for ulnar translation (Taleisnik, Gilula, McMurtry, and Chamay). Results: Bridge plate application to the second metacarpal resulted in a significantly greater incidence of ulnar translation compared to the third metacarpal. Application to either metacarpal resulted in extension of the carpus relative to the radius. Conclusions: A more anatomic radiocarpal relationship was restored more often when distal fixation of the dorsal wrist-spanning bridge plate was applied to the third metacarpal. Further investigation is warranted to determine clinical relevance of these findings in conjunction with clinical and radiographic outcomes.

Assessment of distal radioulnar joint stability in healthy subjects: Changes with dominant hand, sex, and age.

This study aimed to elucidate the differences in distal radioulnar stability in dominant/nondominant hand, sex, and age. Bilateral wrists of 60 healthy subjects were evaluated using force-monitoring ultrasonography. This apparatus was developed to apply cyclic compression and measure applied force to displacement during an ultrasound exam. The transducer was placed on the dorsal side of the distal radioulnar joint, and the center of the ulnar head was displayed on the monitor. The distance between the dorsal surface of the distal radius and the ulnar head was measured at an initial and at a pressed-down position. The radioulnar displacement, applied force to displacement, and displacement-to-force ratio were evaluated. The results were compared between the dominant and nondominant hands, and between males and females, and among different age groups. There were no significant differences in the parameters between the dominant and nondominant hands. The applied force to displacement was significantly greater in the male group compared with the female group. There were significant effects for the different age groups in all parameters (displacement: F = 3.67, p = .008; applied-force: F = 3.08, p = .019; displacement-to-force ratio: F = 4.66, p = .002). Our results indicated that the stability of distal radioulnar joint differed depending on age and sex. Age and sex should be considered when assessing distal radioulnar joint stability.

An insight of how multiple skeletal maturity indices can be used for growth assessment: relationship between the simplified olecranon, simplified digital, and distal radius and ulna classifications.

This cross-sectional study aims to investigate the relationship between the simplified olecranon, simplified digital, and distal radius and ulna (DRU) classifications, and whether they can aid in more comprehensive maturity assessment together. Left hand and wrist and lateral elbow radiographs from pediatric patients were assessed using the three skeletal maturity indices. The association between maturity indices was investigated using Goodman and Kruskal's gamma, and by mapping of individual grades based on chronological age. Specific maturity grades, at which peak height velocity (PHV) occurs as previously identified, were based upon to explore how the three systems interact. A total of 114 patients (63.2% girls) were studied. Correlations and associations between the three maturity parameters were significant (all at P < 0.001). Mapping revealed uneven spans and coverage of different periods by each index. Olecranon stage 1 coincided with R3 (for girls), R4 (for boys), U3, and SS1. Olecranon stage 5 occurred as early as R7, U6, and SS4. Upon elbow fusion, the simplified digital (SS5-SS8) and DRU (R8-R11 and U7-U9) classifications can be used for assessment until maturity. The inter-relationship of the simplified hand, wrist, and olecranon methods indicates their combined use. DRU grades can be used in growth periods which are less well covered. Prepubertal and growth acceleration phase of pubertal growth spurt can best be assessed by both the simplified olecranon (stages 1-3) and DRU classifications (R1-R5 and U1-U4). All three indices are required during PHV. For post-PHV, DRU (R8-R11 and U7-U9) and simplified digital method (SS5-SS8) complement each other for assessment until skeletal maturity.

Three-Dimensional Automated Assessment of the Distal Radioulnar Joint Morphology According to Sigmoid Notch Surface Orientation.

PURPOSE: To develop reproducible 3-dimensional measurements for quantification of the distal radioulnar joint (DRUJ) morphology. We hypothesized that automated 3-dimensional measurement of the ulnar variance (UV) and the sigmoid notch (SN) angle would be comparable to those of the reference standard while overcoming some drawbacks of conventional 2-dimensional measurements. METHODS: Radiological data of healthy forearm bones (radiographs and computed tomography) of 53 adult subjects were included in the study. Automated measurements were developed for assessment of the SN morphology based on 3-dimensional landmarks, incorporating subject-specific estimation of cartilage surface orientation. A common anatomical reference was defined among the different imaging modalities and a comparison of the SN angle and UV measurements was performed in radiographs, computed tomography scans, and 3-dimensional models. Finally, the 3-dimensional UV measurements were evaluated in an experimental setup using 3-dimensional printed bone models. RESULTS: The automated 3-dimensional measurements of SN subtypes showed a notably larger notch radius (18.9 mm) for negative SN angles compared with positive SN angles in subjects (16.9 mm). Similar UV measurements were obtained in healthy DRUJ morphologies, with a high correlation between radiographs and 3-dimensional measurements for the SN angle (0.77) and UV (0.85). In the experimental setup with pathological radial inclinations, UV was on average 1.13 mm larger in the radiographs compared with the 3-dimensional measurements, and 1.30 mm larger in the cases with pathological palmar tilts. Furthermore, UV radiograph measurements on the modified palmar tilt deviated from the 3-dimensional measurements. CONCLUSIONS: The developed 3-dimensional automated measurements were able to quantify morphological differences among sigmoid notch subtypes and were comparable to those of the reference standard. CLINICAL RELEVANCE: The developed methods do not depend on the forearm position or orientation of the distal radius and can be used for 3-dimensional quantification of DRUJ pathologies in 3-dimensional surgical planning.

The importance of radial multiplanar reconstructions for assessment of triangular fibrocartilage complex injury in CT arthrography of the wrist.

BACKGROUND: Triangular fibrocartilage complex (TFCC) lesions commonly cause ulnar-sided wrist pain and instability of the distal radioulnar joint. Due to its triangular shape, discontinuity of the TFCC is oftentimes difficult to visualize in radiological standard planes. Radial multiplanar reconstructions (MPR) may have the potential to simplify diagnosis in CT wrist arthrography. The objective of this study was to assess diagnostic advantages provided by radial MPR over standard planes for TFCC lesions in CT arthrography. METHODS: One hundred six patients (49 women, 57 men; mean age 44.2 ± 15.8 years) underwent CT imaging after wrist arthrography. Two radiologists (R1, R2) retrospectively analyzed three randomized datasets for each CT arthrography. One set contained axial, coronal and sagittal planes (MPRStandard), while the other two included an additional radial reconstruction with the rotating center either atop the ulnar styloid (MPRStyloid) or in the ulnar fovea (MPRFovea). Readers evaluated TFCC differentiability and condition. Suspected lesions were categorized using Palmer's and Atzei's classification and diagnostic confidence was stated on a five-point Likert scale. RESULTS: Compared to standard planes, differentiability of the superficial and deep TFCC layer was superior in radial reconstructions (R1/R2; MPRFovea: p < 0.001; MPRStyloid: p ≤ 0.007). Palmer and Atzei lesions were present in 86.8% (92/106) and 52.8% (56/106) of patients, respectively. Specificity, sensitivity and accuracy for central Palmer lesions did not differ in radial and standard MPR. For peripheral Atzei lesions, sensitivity (MPRStandard 78.6%/80.4%, MPRStyloid 94.6%/94.6%, MPRFovea 91.1%/89.3%) and accuracy (MPRStandard 86.8%/86.8%, MPRStyloid 96.2%/96.2%, MPRFovea 94.3%/93.4%) improved with additional styloid-centered (p = 0.004/0.008) and fovea-centered (p = 0.039/0.125) reconstructions. No substantial difference was observed between both radial MPR (p = 0.688/0.250). Interrater agreement was almost perfect for each dataset (κStandard = 0.876, κStyloid = 0.894, κFovea = 0.949). Diagnostic confidence increased with addition of either radial MPR (p < 0.001). CONCLUSIONS: Ancillary radial planes improve accuracy and diagnostic confidence for detection of peripheral TFCC lesions in CT arthrography of the wrist.

Quantitative Computed Tomography (QCT) of the Distal Forearm in Men Using a Spiral Whole-Body CT Scanner - Description of a Method and Reliability Assessment of the QCT Pro Software.

The Mr F study investigates the pathogenesis of low trauma distal forearm fractures in men and includes volumetric bone mineral density (vBMD) measurements at the ultradistal forearm as there are no current data. A standard 64 slice CT scanner was used to determine if it was possible to adapt the existing Mindways quantitative computed tomography Pro software for measuring vBMD values at the hip and spine sites. For calculation of intra- and interobserver reliability 40 forearm scans out of the 300 available were chosen randomly. The images were analyzed using the Slice Pick module and Bone Investigational Toolkit. The 4% length of the radius was chosen by measuring the length of the radius from the scaphoid fossa distally to the radial head. The acquired image then underwent extraction, isolation, rotation, and selection of region of interest in order to generate a report on vBMD. A cross-sectional image was created to allow the generation of data on the cortical and trabecular components separately. Repeat analyses were undertaken by 3 independent observers who were blinded as to whether the image was from a participant with or without fracture. The images were presented in random order at each time point. The following parameters were recorded: cortical cross sectional area, total vBMD, trabecular vBMD, and cortical vBMD (CvBMD). Data were analyzed by calculating intraclass correlation coefficients for intra- and interobserver reliability. The lowest values occurred at the CvBMD with intraobserver reliability of 0.92 (95% confidence interval [CI] of 0.86-0.96) and interobserver reliability of 0.92 (95% CI 0.89-0.96). All other parameters had reliability values between 0.97 and 0.99 with tighter 95% CI than for CvBMD. The method of adapting the Mindways Pro software using a standard CT to produce vBMD and structural data at the ultradistal radius is reliable.

An Alternative to the Traditional Radiocapitellar Line for Pediatric Forearm Radiograph Assessment in Monteggia Fracture.

OBJECTIVE: To find a new reference for assessment of pediatric forearm radiographs besides the traditional RCL. METHODS: RCLs were drawn on the anteroposterior (AP) and lateral radiographs of 170 normal pediatric forearms. Three lines were drawn on each radiograph: the first was drawn along the longitudinal center of the radial neck (N-line); the second, along the radial shaft (S-line); and the third, through the midpoints of the proximal and distal radial physes (P-line). RESULTS: The P-line was least likely to miss the capitellum on both AP views and lateral views, and the P-line most frequently passed through the central third of the capitellum on both AP views and lateral views. CONCLUSIONS: Our proposed radiocapitellar P-line was found to be much more reliable in younger children than traditional RCLs.

Quantitative assessment of distal radioulnar joint stability with pressure-monitor ultrasonography.

BACKGROUND: Diagnosing distal radioulnar joint (DRUJ) instability remains a challenge as it relies on physical examination. To quantitatively assess DRUJ stability, a pressure-monitor ultrasound system was developed. The objective of this study was to evaluate the force-displacement relationship of DRUJ in normal subjects. METHODS: Nine wrists of 9 asymptomatic volunteers were evaluated. The pressure-monitor ultrasound system was developed to apply pressure to the tissue with a pre-determined cycle and displacement of the transducer. Each subject was imaged sitting with the elbow flexed and forearm pronated. The dorsal surface of the distal radius and the center of the ulnar head were displayed at DRUJ level. The pressure toward palmar direction was applied to the distal ulna with different levels of transducer displacements, i.e., 1 mm, 2 mm, and 3 mm. The distance between the dorsal surface of the ulnar head and the dorsal surface of the distal radius was measured. The first measurement was performed at the initial position, and the second measurement was performed when the transducer pressed down the ulna to the degree that the ulnar head had shifted to the most palmar position. At the same time, the pressure to the transducer was measured. The changes of radioulnar distance (=the measurement at the most palmar position-the measurement at the initial position) and pressure, and pressure/distance ratio were compared among the different transducer displacements. RESULTS: The pressure was significantly increased as the transducer displacement became larger (P < 0.01). The changes of radioulnar distance were smaller in the 1 mm displacement condition compared to the 2 and 3 mm displacement conditions (P < 0.05). The pressure/distance ratio was larger in the 1 mm displacement condition compared to the 2 and 3 mm displacement conditions (P < 0.05). CONCLUSIONS: A method to assess DRUJ stability by measuring changes in radioulnar distance and force application was developed. It was found that the application of 2 mm displacement and 200 g force was the critical stress for the capsuloligamentous structures to start stabilizing DRUJ. This methodology and the indices may be clinically useful to investigate the mechanical properties of patients with DRUJ instability.

Reliability of Quantitative Assessment of Distal Radioulnar Joint Stability With Force-Monitor Ultrasonography.

The purpose of this study was to evaluate the reliability of ultrasound assessment of the displacement-force relationships for distal radioulnar joint (DRUJ) stability. Non-dominant wrists of 10 healthy male subjects were evaluated by force-monitor ultrasonography. This apparatus was developed to apply cyclic compression to the wrist with pre-determined transducer displacement conditions in the range of 0.1-3.0 mm. The subject's wrist was placed on the table with the forearm in the pronated position. The transducer was placed on the dorsal surface of the distal radius and ulna, perpendicular to the long axis of the forearm. The center of the ulnar head was at the DRUJ level. The distance between the dorsal surface of the distal radius and the ulnar head was measured at an initial and a pressed-down position. Changes in radioulnar displacement, force to the wrist and the displacement/force ratio were evaluated. The measurements were performed independently by two raters. The intra-class correlation coefficients (ICCs) for the radioulnar displacement were 0.76, 0.68, and 0.93, in the 1.0, 2.0, and 3.0 mm transducer displacement conditions, respectively. The ICCs for the force to the wrist were 0.18, 0.67, and 0.34, in different transducer displacement conditions, respectively. The ICCs for the displacement/force ratios were 0.68, 0.67, and 0.97, in different transducer displacement conditions, respectively. The highest ICC for the radioulnar displacement and the displacement/force ratio was observed in the 3.0 mm displacement condition. This assessment of displacement-force relationships may be useful to quantify DRUJ stability. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2053-2060, 2019.

Assessment of the degradation rates and effectiveness of different coated Mg-Zn-Ca alloy scaffolds for in vivo repair of critical-size bone defects.

Surgical repair of bone defects remains challenging, and the search for alternative procedures is ongoing. Devices made of Mg for bone repair have received much attention owing to their good biocompatibility and mechanical properties. We developed a new type of scaffold made of a Mg-Zn-Ca alloy with a shape that mimics cortical bone and can be filled with morselized bone. We evaluated its durability and efficacy in a rabbit ulna-defect model. Three types of scaffold-surface coating were evaluated: group A, no coating; group B, a 10-µm microarc oxidation coating; group C, a hydrothermal duplex composite coating; and group D, an empty-defect control. X-ray and micro-computed tomography(micro-CT) images were acquired over 12 weeks to assess ulnar repair. A mechanical stress test indicated that bone repair within each group improved significantly over time (P < 0.01). The degradation behavior of the different scaffolds was assessed by micro-CT and quantified according to the amount of hydrogen gas generated; these measurements indicated that the group C scaffold better resisted corrosion than did the other scaffold types (P < 0.05). Calcein fluorescence and histology revealed that greater mineral densities and better bone responses were achieved for groups B and C than for group A, with group C providing the best response. In conclusion, our Mg-Zn-Ca-alloy scaffold effectively aided bone repair. The group C scaffold exhibited the best corrosion resistance and osteogenesis properties, making it a candidate scaffold for repair of bone defects.

Radiographic assessment of humeroulnar congruity in a medium and a large breed of dog.

Elbow joint incongruity is recognized as an important factor in the development, treatment, and prognosis of canine elbow dysplasia. Elbow incongruity has been measured based on radiographic joint space widths, however these values can be affected by the degree of elbow joint flexion. Recent studies have reported radiographic curvature radii as more precise measures of humeroulnar congruity in dogs. The aim of this prospective observational study was to describe radiographic curvature radii measured from flexed and extended elbow radiographs for a sample of dogs representing a medium breed (Portuguese Pointing Dog) and a large breed (Estrela Mountain Dog). The curvature radii from the ulnar trochlear notch and humeral trochlea were measured in 114 mediolateral elbow extended radiographic views (30 Portuguese Pointing Dog and 27 Estrela Mountain Dog), and 84 mediolateral flexed views (22 Portuguese Pointing Dog and 20 Estrela Mountain Dog). The sampled animals' ages ranged from 12 to 84 months (34.6 ± 17.8 months). Good agreement was observed between curvature radii measurements for flexed vs. extended views in both breed groups. Ulnar trochlear notch curvature radii measurements were greater than humeral trochlea curvature radii measurements in both breed groups. Both curvature radii were greater in the large-breed dog group vs. the medium-breed dog group. Both breed groups had ulnar and humeral curves with similar typology. However, the large breed group had greater intermediate differences between the humeroulnar surface curvature radii. Results from this study supported the use of curvature radii as measures of humeroulnar congruity in mediolateral flexed elbow radiographs of medium and large breed dogs.

Assessment of radial torsion using computed tomography in dogs with and without antebrachial limb deformity.

OBJECTIVE: To evaluate the reliability of radial torsion assessment in dogs using computed tomography (CT). STUDY DESIGN: Cadaveric and retrospective observational clinical study. ANIMALS: Thoracic limbs (n = 40) from bilateral normal cadaveric canine specimens (10 pairs) and unilateral antebrachial angular limb deformity (ALD) dogs (10 uniapical and 10 biapical deformities). METHODS: Limbs were evaluated using CT. Frontal, sagittal, and axial plane (torsion) values were obtained using published guidelines and compared between groups and limbs. Radial torsion reliability was assessed among 3 observers using intraclass correlation coefficients (ICC). RESULTS: The mean (±SD) radial torsion of normal dogs was 3.6° ± 6.4° and contained a significant right to left limb variation of 2.6°. Mean radial torsion in uniapical ALD limbs (3.6° ± 18.7°) was not significantly different from biapical ALD limbs (8.9° ± 17.9°). There was a wide range of torsion values in normal and ALD limbs. The interobserver reliability was excellent (ICC > 0.8) for normal dogs, good (0.73) for uniapical, and excellent (0.89) for biapical ALD limbs. The intraobserver reliability was excellent (>0.8) for all groups. CONCLUSION: There was a small side-to-side variation of radial torsion in normal dogs. With directed training, torsion assessment using CT is reliable in dogs with and without antebrachial bone deformity.

Osseous Anatomy of the Distal Radioulnar Joint: An Assessment Using 3-Dimensional Modeling and Clinical Implications.

PURPOSE: Using a novel technique, we assess and describe the distal radioulnar joint (DRUJ) anatomy. The purpose of this study was to provide the anatomic dimensions of the DRUJ and to evaluate contralateral symmetry. METHODS: Computed tomography images of 100 cadaveric forearms were obtained. Three-dimensional models of the radius and ulna were generated and evaluated using 3-dimensional modeling software. Measurements of the radius of curvature of the sigmoid notch (SN) and ulnar head (UH), as well as the length of the SN and volar and dorsal lips were performed in the axial and coronal sequences. In addition, mid-coronal angular measurements were made of the SN and UH to quantify the obliquity of the DRUJ. All coronal measurements were performed with the forearm set to neutral rotation. RESULTS: The average ulnar variance was -0.9 ± 1.8 mm. The radius of curvature of the UH (8.2 ± 1.3 mm) was markedly smaller than that of the SN (18.2 ± 8.5 mm). The length of the SN in coronal sequences increased from volar to dorsal by 65%. The mid-coronal angle (DRUJ obliquity) of the SN and UH measured 6.0 ± 9.9° and 18.0 ± 9.9°, respectively. A direct inverse correlation was demonstrated in the obliquity of the DRUJ and ulnar variance. All anatomic measurements were similar when comparing bilateral specimens. CONCLUSIONS: The SN length tends to increase in size from volar to dorsal. Bilateral specimens from the same individual demonstrate similarities and can be cautiously used for comparison. CLINICAL RELEVANCE: The relationships and measurements demonstrated in this study can be a guide when considering reconstructive procedures or dealing with complex fractures involving the DRUJ.

Assessment of skeletal age on the basis of DXA-derived hand scans in elite youth soccer.

Physical performance is highly dependent on maturity. Therefore, consideration of maturity is recommended in the talent identification process. To date, skeletal age (SA) is assessed using X-ray scans. However, X-rays are associated with a 10-fold higher radiation compared to dual-energy X-ray absorptiometry (DXA). The aim of the study was to validate SA assessments in male soccer players with the DXA technique. Paired X-ray and DXA scans of the left hand of 63 Swiss U-15 national soccer players were performed. SA assessments were performed twice by two blinded raters using Tanner and Whitehouse' reference technique. Intrarater and interrater reliability as well as agreement between both techniques were tested. Intrarater and interrater reliabilities were excellent. Bland-Altman plots showed that SA assessments between X-ray and DXA differed by -0.2 years and 95% limits of agreement were ±0.6 years. Therefore, DXA offered a replicable method for assessing SA and maturity in youth soccer players.