Computed Tomography Scans Of Wrists Research Articles

Fabricating Stiffness-Matched Three Dimensional -Printed Metal Implants for Total Wrist Arthroplasty.

Total wrist arthroplasty (TWA) is a motion-sparing treatment for pancarpal arthritis; however, complication rates up to 50% have limited widespread use. Implant micromotion, stress shielding, and periprosthetic osteolysis result in implant failure and revision to arthrodesis. Metal 3-dimensional (3D) printing allows for more accurate matching of surrounding bone biomechanical properties, theoretically reducing periprosthetic osteolysis. Herein, we use computed tomography to characterize the relationship of relative stiffness along the length of the distal radius with patient demographic factors. After institutional review, wrist computed tomography scans at a single institution between 2013 and 2021 were identified. Exclusion criteria were history of radius or carpal trauma or fracture. Collected demographics included age, sex, and comorbidities (including osteoporosis/osteopenia). Scans were analyzed using Materialize Mimics Innovation Suite 24.0 (Leuven, Belgium). Distal radius cortical density (in Hounsfield units) and medullary volume (in cubic millimeters) with relation to distance from the radiocarpal joint were recorded. Average values for each variable were used to 3D-printed distal radius trial components with stiffness matched to bone density by length. Thirty-two patients met inclusion criteria. Distal radius cortical bone density progressively increased proximal to the radiocarpal joint, whereas medullary volume decreased; changes in both plateaued 20 mm proximal to the joint. Distal radius material properties differed by age, sex, and comorbidities. Total wrist arthroplasty implants were fabricated to match these variables as proof of concept. Distal radius material properties vary along the bone length; conventional implants do not account for this variance. This study showed 3D-printed implants can be created to match bone properties along the length of the implant.

Radiographic Evaluation of Carpal Mechanics and the Scapholunate Angle in a Clenched Fist with Dynamic Computed Tomography Imaging

The long-term consequences of injuries to the scapholunate joint can severely limit hand function, and the potential for posttraumatic deformity makes early recognition of these injuries important. The purpose of this study was to evaluate the motion of the scapholunate joint in normal wrists through the radial and ulnar deviation using novel dynamic computed tomography (CT) imaging. Fifteen participants consented to have their uninjured wrists scanned. A protocol was designed to ensure adequate time, yet limited exposure, for volunteers. Participants began with the hand in a relaxed fist position and then proceeded to clench the hand in a full fist and relax. Once relaxed again, the wrist was maximally ulnarly deviated and then maximally radially deviated in a fluid motion. Dynamic CT imaging was captured throughout the range of motion. The scapholunate angle was measured on dynamic wrist images. The mean range of the scapholunate angle that the wrists moved through was 37.2°-45.9°, and the mean midpoint angle was 41.2° ± 0.4°. All wrists had small, measurable differences in the scapholunate angle when moving from the maximum ulnar deviation to the maximal radial deviation. The average maximum angle change through the range is 11.7°, whereas the average minimum angle change was 0.9°. In this study, scapholunate angle calculations using dynamic wrist CT scans were within the range of accepted normal for the angle in uninjured wrists. With the increased focus on dynamic imaging for wrist motion, it may be possible to derive a standardized protocol for mapping the carpal motion that is clinically applicable and reproducible. Diagnostic IV.

Association Between Hounsfield Units in Preoperative Wrist Computed Tomography Scans and Outcomes After Wrist Fracture Surgery.

This work aims to evaluate the hypothesis that the value of Hounsfield units (HU), as a marker of bone density, in preoperative wrist computed tomography (CT) scans correlates with the functional outcomes as measured by patient reported outcomes (PROs) after distal radius fracture surgery with volar locking plate fixation. Of a database of 92 wrist fractures operated on in our hospital between 2011 and 2020, with a preoperative CT scan performed, we selected the cases with a minimum follow-up period of 12months. After applying the exclusion criteria, the final cohort comprised 64 patients. Three measurements of HU were performed in correlative coronal sections of the capitate bone. PROs were determined using two functional questionnaires (DASH and PRWE) and one quality of life questionnaire (SF-12). The statistical relationship between PROs and the HU measurements obtained via a CT scan was analyzed. Patients were classified into two groups, osteoporotic (OST) or non-osteoporotic (non-OST), according to the optimal cut-off value of 323 HU selected using a ROC curve. The median DASH questionnaire score in the OST group was significantly higher (1.7 vs 10.0, p = 0.003). HU values in preoperative wrist CT scans may help to identify osteoporotic bone in patients prior to wrist fracture surgery and lead to an improved surgical indication and treatment strategy. Level of evidence: Prognostic III.

Structural Versus Nonstructural Bone Grafting for the Treatment of Unstable Scaphoid Waist Nonunion Without Avascular Necrosis: A Randomized Clinical Trial

We evaluated the impact of structural versus nonstructural bone grafting on the time to union, scaphoid deformity correction, and clinical outcomes in adults with unstable scaphoid waist nonunion without avascular necrosis. We hypothesized that nonstructural grafting would provide earlier time to union, restoration of scaphoid anatomy, and equivalent clinical outcomes compared with structural grafting. We prospectively randomized 98 patients to undergo open reduction, iliac crest bone grafting with either corticocancellous (CC group) or cancellous bone only (C-only), and internal fixation using a Herbert screw. The lateral intrascaphoid angle (LISA) and scaphoid height length ratio (HLR) were measured on wrist computed tomography scans along the scaphoid longitudinal axis before surgery and an average of 84 weeks afterward. Pain, range of motion, grip strength, and Quick-Disabilities of the Arm, Shoulder, and Hand (QuickDASH) score were measured before surgery and an average 84 weeks afterward. The trajectory of scaphoid union showed a higher union rate of the C-only group at 12, 14, and 16 weeks after surgery. However, at 24 weeks after surgery, there was no difference between the groups, The union rate was 94% in patients treated with C-only and 90% with CC grafting. In patients with preoperative LISA less than 70° and/or HLR less than 0.80 (n= 53), there were no differences between the CC and C-only grafting techniques for radiographic and clinical outcomes, QuickDASH scores, and malunion rate. In patients who had preoperative LISA greater than 70° and/or HLR greater than 0.80 (n= 45), radiographic outcome measures, range of motion, and QuickDASH scores were significantly better in the CC than in the C-only group. Scaphoid malunion was observed in 9 of 22 of C-only patients (41%) and 4 of 23 of CC patients (18%). The severity of the scaphoid deformity may be a factor in determining the best graft type, because this may affect the rate of successful deformity correction. Corticocancellous grafting in patients who had a high degree of scaphoid deformity provided consistent deformity correction and superior QuickDASH scores. Otherwise, C-only grafting provides earlier time to union and equivalent clinical and radiographic outcomes compared with CC grafting. Therapeutic I.

Morphometric Variations of Scaphoid and Safety of Screw Fixation for Its Waist Zone Fractures in Indian Population: A Preliminary Report

Purpose Surgeons fixing scaphoid fractures need to be familiar with their morphological variations and their implications for safe screw placement during fixation. The purpose of this computed tomography (CT)-based study was to analyze the anatomical limits of safe screw placement for scaphoid waist fractures in the Indian population. Methods We measured the coronal and sagittal dimensions of the scaphoid in 3 zones: proximal, waist, and distal, in CT scans of wrists with intact scaphoids obtained from 50 live subjects. In addition, we studied the curvature of the scaphoid, its longitudinal extent, and the safe placement of trajectories for different screw diameters. Results The proximal segment had the narrowest mean coronal width of 6.39 mm, whereas the waist region had the narrowest mean sagittal width of 9.02 mm. Mean scaphoid curvature was 132.23°. Maximal bony extent of the scaphoid was significantly higher than the mean length of screw placed centrally in the mid-waist region. Conclusions This study showed that there is a considerable amount of variation in scaphoid morphometry in Indian patients. All scaphoids capable of safely containing a single 4-mm screw or 2 parallel 1.7-mm screws coplanar in the sagittal plane. Surgeons treating these fractures should consider a CT-based analysis to plan the screw direction and length and need to be familiar with the morphometric variations of the scaphoid. Clinical relevance The measurements and techniques in this study may be helpful in understanding morphometric variations of the scaphoid and in planning surgery for fixation of fractures around its waist region.

The Use of Distal Ulnar Hounsfield Units to Predict Future Fragility Fracture Risk.

Distal ulnar Hounsfield unit (HU) measurements obtained from computed tomography (CT) scans of the wrist can be used to accurately screen for low bone mineral density. It is unknown whether HU measurements can also predict the risk of future fragility fractures. Therefore, the purpose of this study was to determine if the HU values of the distal ulna correlate to fragility fracture risk. An electronic database of radiographs at a single institution was searched for all wrist CT scans, obtained for any reason, between January 1, 2002, and December 31, 2008, to allow a minimum of 5-year follow-up. Manual measurement of HU on sequential coronal CT slices of the distal ulnar head was taken, and mean values were recorded. Previously determined cutoff values for the diagnosis of low bone mineral density were implemented to stratify patients as at risk or not at risk for future fragility fracture. Medical records were then manually reviewed for the occurrence of any future fragility fracture (hip, spine, proximal humerus, or rib). There were 161 CTs in 157 patients and 34 fragility fractures in 21 patients, with a prevalence of 13.4%. The mean HU in the fragility fracture group was significantly lower(134.2 vs 197.1 HU). The percentage of low HU patients with fragility fractures was significantly higher (22.7% vs 3.8%). The odds ratio for fragility fracture in the low HU group was 7.4 (95% confidence interval, 2.1-26.2). Using previously determined cutoff values, the sensitivity and specificity of distal ulna HU values for identifying patients who would sustain at least 1 future fragility fracture were 85.7% and 55.2%, respectively. Patients with low distal ulnar HU were significantly more likely to sustain a subsequent fragility fracture. A determination of distal ulnar HUs represents a quick, simple tool to identify patients potentially at risk for fragility fractures. Prognostic IV.

Distal Ulnar Hounsfield Units Accurately Predict Bone Mineral Density and Future Fragility Fracture Risk: Level 3 Evidence

There is no financial information to disclose. Hounsfield unit (HU) measurement from wrist computed tomography (CT) may provide an effective screening tool for low bone mineral density (BMD). We hypothesized that HU measurements from wrist CT scans would accurately evaluate forearm BMD, and low HU values would effectively predict the occurrence of fragility fractures. An electronic database of radiographs was queried for all wrist CT scans obtained at a single institution, and a database of all active duty and military dependents was cross-referenced with the CT scan population to identify all patients with both wrist CT and DXA. Hounsfield unit measurements were performed by one author blinded to DXA results on sequential coronal CT slices of the distal ulnar head. Average HU values were compared to forearm and femoral neck T-score determined by DXA scan. Medical records were then manually reviewed for the occurrence of any fragility fracture. There were 161 CTs in 159 patients included; 74 patients also had available DXA scans. For the population with both CT and DXA, average HU were significantly lower in the DXA-confirmed osteoporotic and osteopenic groups when compared to the normal BMD group (98.1 and 126.9HU versus 198.6HU, respectively, P < 0.0001). The upper limit 95% confidence interval for forearm osteopenia patients was 145.8HU. Overall, the prevalence of fragility fractures was 15.7%. Average HU in the fragility fracture group was significantly lower (126.2 versus 200.5HU, P < 0.0001). The percentage of patients with HU below 145.8HU who subsequently sustained fragility fractures was significantly higher (29.5% versus 2.5%, P < 0.0001). The odds ratio for fragility fracture in the low HU group was 16.9 (range: 3.8 to 74.6). The sensitivity of forearm HU for fragility fracture risk was 92.3%, with a negative predictive value of 97.5%. •Patients with low BMD of the forearm and femoral neck had significantly lower HU measurements in the distal ulna on CT when compared to patients with normal BMD, and measurements below 145.8HU were strongly associated with low BMD.•Patients with HU below 145.8HU were 16 times more likely to sustain a subsequent fragility fracture. Using this cutoff, we were able to predict 92% of fragility fractures.•Distal ulnar HU measurements can be performed easily to identify patients with osteoporosis, and to accurately recognize patients at significant risk for fragility fractures.

Brief Report: Development and Validation of a Semiautomated Method to Measure Erosion Volume in Inflammatory Arthritis by Computed Tomography Scanning

ObjectiveValid measurement of erosion volume in rheumatoid arthritis (RA) will facilitate the testing of treatments that may help to heal erosion. This study was undertaken to develop and validate a software method to measure erosion volume on computed tomography (CT) scans of the hand and wrist.MethodsDuplicate CT acquisitions of both hands of 5 patients with RA were evaluated using a semiautomated software tool to measure erosion volume in the entire hand and wrist and in each of 6 subregions. Reproducibility was quantified using the intraclass correlation coefficient (ICC), root mean square standard deviation (RMSSD), and coefficient of variation (CV), and the analysis was performed at the level of the hand (n = 10) and the subject (n = 5).ResultsThe ICCs between 2 repositioned acquisitions were excellent, ranging from 0.97 to 1.00. At the hand level, the RMSSD was 15.6 mm3 with a CV of 7.3%, and the CVs at the 6 regions ranged from 7.6% to 21.0%. At the subject level, the RMSSD was 31.2 mm3 with a CV of 3.7%, and the CVs at the 6 regions ranged from 0.5% to 15.8%.ConclusionWe have developed a novel semiautomated software method to measure erosion volume on hand and wrist CT scans. The method is reproducible and can be used to detect changes in erosion volume. This will facilitate the testing of treatments intended to reduce erosion volume.

Opportunistic Osteoporosis Screening— Gleaning Additional Information from Diagnostic Wrist CT Scans

Although screening for and treating osteoporosis can prevent subsequent fractures, the rates of such interventions are low following a distal radial fracture. One potential method for identifying metabolic bone disease is via Hounsfield unit (HU) measurements from diagnostic computed tomography (CT) scans. We hypothesized that HU values of the distal aspect of the radius could be used to assess local bone quality and would be predictive of distal radial fracture risk, thereby allowing the identification of patients in need of further management. Measurements of bone mineral density (BMD) were made for 100 patients on the basis of HU values of cancellous portions of the distal aspect of the radius, the ulnar head, and the capitate. The HU values in twenty-five male and twenty-five female patients with an acute distal radial fracture documented on CT were compared with those of age and sex-matched control patients who had a CT scan obtained for other indications. Among the control patients, HU values decreased as age increased. When assessed on the basis of sex, both male and female patients with a distal radial fracture had significantly lower regional BMD compared with nonfracture control patients. A distal radial HU value of 218 for females and 246 for males optimized sensitivity and specificity; values below this threshold were associated with an increased risk of distal radial fracture. HU measurements can be obtained from any diagnostic CT scan using modern software programs and can be obtained by physicians in the office setting with minimal effort and at no additional cost or radiation exposure to the patient. Regardless of imaging indications, we suggest that patients with HU values below the identified thresholds be considered for further metabolic bone disease work-up, such as additional imaging, laboratory assessments, the initiation of osteoporosis treatment, or appropriate referral.

Semiautomated three‐dimensional segmentation software to quantify carpal bone volume changes on wrist CT scans for arthritis assessment

Rapid progression of joint destruction is an indication of poor prognosis in patients with rheumatoid arthritis. Computed tomography (CT) has the potential to serve as a gold standard for joint imaging since it provides high resolution three-dimensional (3D) images of bone structure. The authors have developed a method to quantify erosion volume changes on wrist CT scans. In this article they present a description and validation of the methodology using multiple scans of a hand phantom and five human subjects. An anthropomorphic hand phantom was imaged with a clinical CT scanner at three different orientations separated by a 30-deg angle. A reader used the semiautomated software tool to segment the individual carpal bones of each CT scan. Reproducibility was measured as the root-mean-square standard deviation (RMMSD) and coefficient of variation (CoV) between multiple measurements of the carpal volumes. Longitudinal erosion progression was studied by inserting simulated erosions in a paired second scan. The change in simulated erosion size was calculated by performing 3D image registration and measuring the volume difference between scans in a region adjacent to the simulated erosion. The RMSSD for the total carpal volumes was 21.0 mm3 (CoV = 1.3%) for the phantom, and 44.1 mm3 (CoV = 3.0%) for the in vivo subjects. Using 3D registration and local volume difference calculations, the RMMSD was 1.0-3.0 mm3 The reader time was approximately 5 min per carpal bone. There was excellent agreement between the measured and simulated erosion volumes. The effect of a poorly measured volume for a single erosion is mitigated by the large number of subjects that would comprise a clinical study and that there will be many erosions measured per patient. CT promises to be a quantifiable tool to measure erosion volumes and may serve as a gold standard that can be used in the validation of other modalities such as magnetic resonance imaging.