Radiation exposure from musculoskeletal computerized tomographic scans

The Effect of Low-Dose CT Protocols on Shoulder Model-Based Tracking accuracy Using Biplane Videoradiography

PURPOSE

Model-based tracking is being increasingly used to quantify shoulder kinematics and typically employs computed tomography (CT) to create the 3D bone volumes, which adds to the total radiation exposure. Lower-dose CT protocols may be possible given the contrast between bone and the surrounding soft tissues. The purpose of this study was to describe the dose-accuracy tradeoff between low-dose CT scans and the kinematic tracking accuracy of the humerus, scapula, and clavicle when tracked using an intensity-based registration algorithm.

METHODS

Three fresh-frozen cadavers consisting of the torso and bilateral shoulders were tested. The CT protocols investigated included a full-dose protocol and 4 experimental low-dose protocols that modulated x-ray tube current and peak voltage. Bead-based tracking (i.e., radiostereometric analysis) served as the reference standard to which model-based tracking results were compared. Accuracy was described in terms of both segmental (humerus, scapula, and clavicle) and joint (glenohumeral, acromioclavicular) kinematics using root-mean-square (RMSE), bias, precision, and worst-case errors.

RESULTS

The low-dose CT scans resulted in an average dose reduction of 70.6-92.8%. RMSEs tended to increase as CT dose decreased with average glenohumeral errors increasing from 0.5° and 0.6 mm to 0.6° and 0.6 mm between the highest and lowest-dose protocols, and average acromioclavicular errors increasing from 0.6° and 0.8 mm to 0.7° and 0.9 mm. However, the difference in joint kinematic errors between the highest and lowest-dose CT scanning protocols was generally small (≤0.3°, ≤ 0.1 mm).

CONCLUSION

It is possible to substantially reduce the CT dose associated with shoulder motion analysis using biplane videoradiography without significantly impacting data fidelity.

Transphyseal Hemiepiphysiodesis: Is it Truly Reversible?

BACKGROUND

Although numerous studies reported the efficacy of percutaneous epiphysiodesis using transphyseal screws (PETS) in correcting angular knee deformities, many surgeons refrained from using it in younger children because of a lack of objective evidence of reversibility. Our hypothesis is that PETS is both truly reversible and effective.

METHODS

Twenty-one patients aged 8 to 13 years (36 lower limbs LL) with coronal plane knee deformity were enrolled into this prospective case series from January 2021 to September 2023. Besides the routine monitoring of PETS efficacy, low dose CT knee of 32 treated physes was done 6 months after screw removal. In addition, lower limb length, mechanical lateral distal femur angle (mLDFA), and medial proximal tibial angle (MPTA) were recorded preoperatively and 6 to 17 months after screw removal for 24 LL to investigate physis behavior, technique reversibility, and resumption of bone growth after screw removal.

RESULTS

The mean mechanical axis deviation (MAD) correction rate was 3.46 mm/mo and 1.78 mm/mo for genu valgum and genu varum patients, respectively. No physeal bony bars could be detected 6 months after screw removal for all patients. Out of 24 physis that underwent computerized radiography (CR) of the whole lower limb, 12 LL resumed their growth, 4 were stationary, while 8 were excluded due to inadequate calibration. A single physis showed rebound deformity, and another showed overcorrection in the genu valgum group.

CONCLUSIONS

In addition to being a highly effective method of hemiepiphysiodesis, PETS was found to be reproducible, safe, and reversible when used in the juvenile and early adolescent pediatric population.

LEVEL OF EVIDENCE

IV-Prospective case series.

A new era of high-resolution CT diagnostics of the lung: improved image quality, detailed morphology, and reduced radiation dose with high-resolution photon-counting CT of the lungs compared to high-resolution energy-integrated CT

BACKGROUND

High-resolution computed tomography (HRCT) is dependent on detailed morphology in diagnostic assessment of interstitial lung diseases. Photon-counting CT (PCCT) enables improved resolution while reducing radiation.

PURPOSE

To compare if the image quality, detailed morphology, and radiation dose in HRCT of the lung improves with PCCT compared to energy-integrated CT (EICT).

MATERIAL AND METHODS

HRCT with PCCT in patients with body mass index (BMI) from normal to obese, previously examined with different EICT were included. They were evaluated in a five-step scale for image quality according to Quality Criteria for CT (Diagnostic Requirement of the ImPACT group-European standardization). In addition, ground-glass opacities, bronchiectasis, emphysema, nodules, and subpleural detailed morphology (≤1 cm from the pleural border) were evaluated by three independent thoracic and/or pediatric radiologists. Visual grading characteristics (VGC) were used for comparison of image quality and detailed morphology and Fleiss kappa for intra-observer variability. Dose-length product (DLP) and CT dose index-volume (CTDIvol) were collected to calculate effective radiation dose.

RESULTS

HRCT with PCCT in 52 women and 48 men (mean age=67.2 ± 13.6 years; age range=27-87 years; BMI=26.9 kg/m2; range=18.6-45 kg/m2) previously examined with EICT (mean age=65.3 ± 13.6 years; age range=27-85 years; BMI=27 kg/m2; range=18.9-45 kg/m2) were included. There were significant differences in image quality for all entities in favor of PCCT. The radiation dose was reduced with PCCT by 47% in all, particularly pronounced in obese with 48.5%.

CONCLUSION

Image quality, detailed morphology, and radiation dose, particularly in obese patients, were significantly improved in HRCT with PCCT compared to conventional EICT. The new technique enables visualization of subpleural structures.

Imaging of MSK infections in the ER

Musculoskeletal infections in the ER are not an uncommon presentation. The clinical context is critical in determining the suspicion for infection and degree of tissue involvement which can involve all layers from the skin to bones. The location, extent, and severity of clinically suspected infection directly relate to the type of imaging performed. Uncomplicated cellulitis typically does not require any imaging. Localized and superficial infections can mostly be evaluated with ultrasound. If there is a diffuse site (an entire extremity) or suspected deeper involvement (muscle/deep fascia), then CT is accurate in diagnosing, widely available, and performed quickly. With potential osseous involvement, MRI is the gold standard for diagnosing acute osteomyelitis; however, it has the drawbacks of longer scan times, artifacts including patient motion, and limited availability.

Quantitative Measurement of Rotation in Phalangeal Fracture Malunion Using Computed Tomography Imaging-"Linkage Simulation"

Malunion of thumb and finger fractures causes problems in the cosmetic and functional aspects of the hand. Malunion of phalangeal fractures usually manifests as a combination of rotational deformities in the coronal, sagittal, and transverse planes, and corrective osteotomy is performed on the planes that cause these problems. Quantification of the deformity is essential for precise osteotomy and is difficult to perform in the transverse plane, even with radiography or computed tomography. Thus, we developed a technique called linkage simulation for the quantitative measurement of rotational deformities for surgical planning. In this procedure, finger extension and flexion can be simulated based on the predicted rotational axis of the joint, which is useful for determining the appropriate correction. Furthermore, by performing a reduction simulation in the software, it is possible to simulate the surgery and predict the postoperative results. This paper reports the details of this technique.

Geometric accuracy of low-dose CT scans for use in shoulder musculoskeletal research applications

Computed tomography (CT) imaging is frequently employed in a variety of musculoskeletal research applications. Although research studies often use imaging protocols developed for clinical applications, lower dose protocols are likely possible when the goal is to reconstruct 3D bone models. Our purpose was to describe the dose-accuracy trade-off between incrementally lower-dose CT scans and the geometric reconstruction accuracy of the humerus, scapula, and clavicle. Six shoulder specimens were acquired and scanned using 5 helical CT protocols: 1) 120 kVp, 450 mA (full-dose); 2) 120 kVp, 120 mA; 3) 120 kVp, 100 mA; 4) 100 kVp, 100 mA; 5) 80 kVp, 80 mA. Scans were segmented and reconstructed into 3D surface meshes. Geometric error was assessed by comparing the surfaces of the low-dose meshes to the full-dose (gold standard) mesh and was described using mean absolute error, bias, precision, and worst-case error. All low-dose protocols resulted in a >70 % reduction in the effective dose. Lower dose scans resulted in higher geometric errors; however, error magnitudes were generally <0.5 mm. These data suggest that the effective dose associated with CT imaging can be substantially reduced without a significant loss of geometric reconstruction accuracy.

Demonstrating the use of population level data to investigate trends in the rate, radiation dose and cost of Computed Tomography across clinical groups: Are there any areas of concern?

INTRODUCTION

Increases in computed tomography (CT) use may not always reflect clinical need or improve outcomes. This study aimed to demonstrate how population level data can be used to identify variations in care between patient groups, by analysing system-level changes in CT use around the diagnosis of new conditions.

METHODS

Retrospective repeated cross-sectional observational study using West Australian linked administrative records, including 504,723 adults diagnosed with different conditions in 2006, 2012 and 2015. For 90 days pre/post diagnosis, CT use (any and 2+ scans), effective dose (mSv), lifetime attributable risk (LAR) of cancer incidence and mortality from CT, and costs were assessed.

RESULTS

CT use increased from 209.4 per 1000 new diagnoses in 2006 to 258.0 in 2015; increases were observed for all conditions except neoplasms. Healthcare system costs increased for all conditions but neoplasms and mental disorders. Effective dose increased substantially for respiratory (+2.5 mSv, +23.1%, P < 0.001) and circulatory conditions (+2.1 mSv, +15.4%, P < 0.001). The LAR of cancer incidence and mortality from CT increased for endocrine (incidence +23.4%, mortality +18.0%) and respiratory disorders (+21.7%, +23.3%). Mortality LAR increased for circulatory (+12.1%) and nervous system (+11.0%) disorders. The LAR of cancer incidence and mortality reduced for musculoskeletal system disorders, despite an increase in repeated CT in this group.

CONCLUSIONS

Use and costs increased for most conditions except neoplasms and mental and behavioural disorders. More strategic CT use may have occurred in musculoskeletal conditions, while use and radiation burden increased for respiratory, circulatory and nervous system conditions. Using this high-level approach we flag areas requiring deeper investigation into appropriateness and value of care.

Comparison of conventional MR arthrography and 3D volumetric MR arthrography in detection of cartilage defects accompanying glenoid labrum pathologies

OBJECTIVES

In this study, we aimed to compare conventional and T1-weighted volumetric magnetic resonance arthrography (MRA) in the diagnosis and grading of glenoid cartilage defects that accompany labral pathologies.

MATERIALS AND METHODS

A total of 79 patients who were prediagnosed with labrum pathologies based on shoulder magnetic resonance imaging (MRI) had MRA and CTA between December 2021 and May 2022. CTA was regarded as reference standard. CTA images were examined by a radiologist experienced in musculoskeletal radiology, and MRA images were examined by two radiologists independently to determine presence, grade, and localization of any glenoid cartilage defect, if present. Sensitivity, specificity, and accuracy were calculated separately for conventional and T1-weighted volumetric MRA. In addition, at the last stage, two observers examined all MRAs together, and the presence of a cartilage defect was decided by consensus, and the overall sensitivity, specificity, and accuracy were calculated.

RESULTS

Cartilage defect was detected on CTAs of 48 (60.75%) cases of among 79 patients with labrum pathology. The sensitivity, specificity, and accuracy of conventional MRA for two examiners were 17-19%, 100-100%, and 49-51%, respectively, while those values were 67-65%, 92-97%, and 84-77%, respectively, for T1-weighted volumetric MRA. Inter-examiner agreement was excellent for diagnosis of cartilage defects on all MRAs. The overall sensitivity, specificity, and accuracy for detection of glenoid cartilage lesions by MRA were 69%, 97%, and 80%, respectively.

CONCLUSION

T1-weighted volumetric MRA seems to demonstrate cartilage defects accompanied with labrum pathologies accurately with high sensitivity, specificity, and excellent inter-examiner agreement.

Advances in Imaging (Intraop Cone-Beam Computed Tomography, Synthetic Computed Tomography, Bone Scan, Low-Dose Protocols)

Spine surgery has seen a rapid advance in the refinement and development of 3-dimensional and nuclear imaging modalities in recent years. Cone-beam CT has proven to be a valuable tool for improving the accuracy of pedicle screw placement. The use of synthetic CT and low-dose CT have also emerged as modalities which allow for little to no radiation while streamlining imaging workflows. Bone scans also serve to provide functional information about bone metabolism in both the preoperative and postoperative monitoring phases.

Measuring External Rotation of the Fibula and Fibular Length in Bilateral Computed Tomography Scans: How Reliable Is This Method?

OBJECTIVES

During ankle fracture surgery, goals include accurate reduction and fixation of the fibula regarding rotation and fibular length. Bilateral postoperative computed tomography (CT) can be performed to assess fibular rotation using the talar dome angle, and fibular length. The aim of this study was to compare side-to-side differences of the fibular rotation and fibular length using bilateral CT scans of uninjured ankles.

METHODS

DESIGN

Retrospective.

SETTING

Single center, Level I Academic Trauma Center.

PATIENT SELECTION CRITERIA

Patients with bilateral CT scans of uninjured ankles.

OUTCOME MEASURES AND COMPARISONS

External rotation using the Nault talar dome method and fibular length using the coronal method of Prior et al. The average, difference, and ratio (injured side/healthy side) and interobserver variability were calculated.

RESULTS

There were 83 patients included (166 ankles, mean age 47 years, 77.1% male). A random set of 66 ankles (33 CT scans) were used to measure interobserver variability. The mean degrees of external rotation ranged from 6.6 to 7.7, mean difference ranged from 1.4 to 3.4 degrees, mean ratio ranged from 1.1 to 1.5, and interobserver variability ranged from 0.27 to 0.65. For fibular length, the mean ranged from 24.6 to 25.8 mm, mean difference in fibular length ranged from 0.5 to 2.1 mm, mean ratio ranged from 1.0 to 1.1 mm, and interobserver variability ranged from 0.45 to 0.73.

CONCLUSIONS

Using bilateral ankle CT scans, mean differences in fibular rotation using the Nault talar dome method were 1.4-3.4 degrees. The distal fibular length had a mean difference between both sides of 0.5-2.1 mm. Although the intraclass correlation's were low, the interleg differences between patients were small, making them useful for clinical practice.

LEVEL OF EVIDENCE

Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Superior metal artifact reduction of tin-filtered low-dose CT in imaging of lumbar spinal instrumentation compared to conventional computed tomography

OBJECTIVE

To compare the image quality of low-dose CT (LD-CT) with tin filtration of the lumbar spine after metal implants to standard clinical CT, and to evaluate the potential for metal artifact and dose reduction.

MATERIALS AND METHODS

CT protocols were optimized in a cadaver torso. Seventy-four prospectively included patients with metallic lumbar implants were scanned with both standard CT (120 kV) and tin-filtered LD-CT (Sn140kV). CT dose parameters and qualitative measures (1 = worst,4 = best) were compared. Quantitative measures included noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and the width and attenuation of the most prominent hypodense metal artifact. Standard CT and LD-CT were assessed for imaging findings.

RESULTS

Tin-filtered LD-CT was performed with 60% dose saving compared to standard CT (median effective dose 3.22 mSv (quartile 1-3: 2.73-3.49 mSv) versus 8.02 mSv (6.42-9.27 mSv; p < .001). Image quality of CT and tin-filtered low-dose CT was good with excellent depiction of anatomy, while image noise was lower for CT and artifacts were weaker for tin-filtered LD-CT. Quantitative measures also revealed increased noise for tin-filtered low-dose CT (41.5HU), lower SNR (2) and CNR (0.6) compared to CT (32HU,3.55,1.03, respectively) (all p < .001). However, tin-filtered LD-CT performed superior regarding the width and attenuation of hypodense metal artifacts (2.9 mm and -767.5HU for LD-CT vs. 4.1 mm and -937HU for CT; all p < .001). No difference between methods was observed in detection of imaging findings.

CONCLUSION

Tin-filtered LD-CT with 60% dose saving performs comparable to standard CT in detection of pathology and surgery related complications after lumbar spinal instrumentation, and shows superior metal artifact reduction.

Comparative analysis of radiation exposure in robot-assisted total knee arthroplasty using popular robotic systems

Robotic-assisted TKA (RATKA) is a rapidly emerging technique that has been shown to improve precision and accuracy in implant alignment in TKA. Robotic-assisted TKA (RATKA) uses computer software to create a three-dimensional model of the patient's knee. Different types of preoperative imaging, including radiographs and CT scans, are used to create these models, each with varying levels of radiation exposure. This study aims to determine the radiation dose associated with each type of imaging used in RATKA, to inform patients of the potential risks. A retrospective search of our clinical radiology and arthroplasty database was conducted to identify 140 knees. The patients were divided into three groups based on the type of preoperative imaging they received: (1) CT image-based MAKO Protocol, (2) Antero-posterior long leg alignment films (LLAF), (3) standard AP, lateral, and skyline knee radiographs. The dose of CT imaging technique for each knee was measured using the dose-length product (DLP) with units of mGycm2, whereas the measurement for XRAY images was with the dose area product (DAP) with units of Gycm2. The mean radiation dose for patients in the CT (MAKO protocol) image-based group was 1135 mGy.cm2. The mean radiation dose for patients in the LLAF group was 3081 Gycm2. The mean radiation dose for patients undergoing knee AP/lateral and skyline radiographs was the lowest of the groups, averaging 4.43 Gycm2. Through an ANOVA and post hoc analysis, the results between groups was statistically significant. In this study, we found a significant difference in radiation exposure between standard knee radiographs, LLAF and CT imaging. Nonetheless, the radiation dose for all groups is still within acceptable safety limits.

T1-VIBE and STIR MRI of lumbar pars interarticularis injuries in elite athletes: fracture characterisation and potential prognostic indicators

OBJECTIVES

To assess how pars interarticularis fracture characteristics on T1-VIBE and STIR MRI relate to healing and identify anatomical parameters that may impact healing.

MATERIALS AND METHODS

A retrospective review of an MRI series of lumbar pars interarticularis injuries in elite athletes over a 3-year period. Fracture configurations, signal intensities and anatomical parameters were recorded by two radiologists. Statistical analysis employed multilevel mixed-effects linear regressions, adjusted for repeated measures and baseline covariates.

RESULTS

Forty-seven lumbar pars interarticularis injuries among 31 athletes were assessed. On final scans for each athlete, 15% (7/47) injuries had worsened, 23% (11/47) remained stable, 43% (20/47) partially healed and 19% (9/47) healed completely. Healing times varied, quickest was 49 days for a chronic fracture in a footballer. Bone marrow oedema signal was highest in worsened fractures, followed by improved, and lowest in stable fractures. As healing progressed, T1-VIBE signal at the fracture line decreased. Bone marrow oedema and fracture line signal peaked at 90-120 days before decreasing until 210-240 days. Fractures with smaller dimensions, more vertical orientation and a longer superior articular facet beneath were significantly associated with better healing (p < 0.05).

CONCLUSION

Most diagnosed athletic pars interarticularis injuries improve. Normalising T1-VIBE signal at the fracture line is a novel measurable indicator of bony healing. Contrastingly, bone marrow oedema signal is higher in active fractures irrespective of healing or deterioration. Injuries initially perceived as worsening may be exhibiting the normal osteoclastic phase of healing. Better outcomes favour smaller, vertical fractures with a longer superior articular facet beneath.

Orientation of the Scapula in the Standing Position

OBJECTIVES

A new ultrasound-based device is proposed to non-invasively measure the orientation of the scapula in the standing position to consider this parameter for Total Shoulder Arthroplasty. The aim of this study was to assess the accuracy and reliability of this device.

METHODS

Accuracy was assessed by comparing measurements made with the ultrasound device to those acquired with a three-dimensional (3D) optical localization system (Northern Digital, Canada) on a dedicated mechanical phantom. Three users performed 10 measurements on three healthy volunteers with different body mass (BMI) indices to analyze the reliability of the device by measuring the intra and interobserver variabilities.

RESULTS

The mean accuracy of the device was 0.9°± 0.7 (0.01-3.03), 1.3°± 0.8 (0.03-4.55), 1.9°± 1.5 (0.05-5.76), respectively, in the axial, coronal, and sagittal planes. The interobserver and intraobserver variabilities were excellent whatever the BMI and the users experience.

CONCLUSIONS

The device is accurate and reliable enough for the measurement of the scapula orientation in the standing position.

In-vivo kinematics of the trapeziometacarpal joint in dynamic pinch motion using four-dimensional computed tomography imaging

OBJECTIVE

CT imaging precisely and quantitatively analyzes the kinematics of the carpal bones to evaluate the etiology of related osteoarthritis. Previous studies have investigated the kinematics of the trapeziometacarpal joint using static CT scans of various postures including the pinch position. This study analyzed the in-vivo kinematics of the trapeziometacarpal joint during dynamic pinch motion in young healthy volunteers using four-dimensional CT.

MATERIALS AND METHODS

Twelve healthy young volunteers participated in this study. Each participant held the pinch meter between their thumb and index finger and pinched it with maximum force for a period of 6 s. This series of movement was recorded using a four-dimensional CT. The surface data of the trapezium and first metacarpal of all frames were reconstructed, and bone movement at the trapeziometacarpal joint was calculated using sequential three-dimensional registration. The instantaneous pinch force of each frame was measured using a pointer on a pinch meter that was reconstructed from the CT data.

RESULTS

The first metacarpal was abducted (15.9 ± 8.3°) and flexed (12.2 ± 7.1°) relative to the trapezium, and significantly translated to the volar　(0.8 ± 0.6 mm) and ulnar directions (0.9 ± 0.8 mm) with maximum pinch force. This movement consistently increased with the pinch force.

CONCLUSION

This study successfully employed 4D-CT to precisely demonstrate changes in rotation and translation at the trapeziometacarpal joint during pinch motion for various instantaneous forces.

Minimally Invasive Percutaneous Screw Guided by 3-Dimensional-Printed Guide for the Treatment of Scaphoid Fractures

PURPOSE

This study aimed to explore the feasibility and efficacy of percutaneous fixation of minimally displaced scaphoid waist fractures using a 3-dimensional-printed guide in 10 cases.

METHODS

Fractures were examined using preoperative computed tomography. The skin interface and bone models were reconstructed using computed tomography data. Guidewire insertion was assisted by a guide. Computed tomography was performed 4-6 weeks after surgery until healing of the fracture was confirmed. The mean follow-up period was 7 months (range, 6-9 months). The fracture healing time, grip strength, flexion-extension arc, patient-rated wrist evaluation, and Mayo wrist score were recorded.

RESULTS

A total of 6 hands were in the dominant limb. The mean operation time was 41 minutes (range, 32-70 minutes). Three (30%) scaphoids healed at 6 weeks after surgery, 8 (80%) scaphoids healed at 8 weeks after surgery, and 100% scaphoids healed at 12 weeks after surgery. After correcting for hand dominance, the mean grip strength was 84% (range, 71% to 95%) of that of the contralateral side. The flexion-extension arc was 97% (range, 82% to 100%) of that of the contralateral side. The mean Mayo wrist score was 95 (range, 85-100), and pain decreased to minimal levels. All patients returned to their preinjury activities.

CONCLUSIONS

Three-dimensional printing is an effective and feasible technology that can help guide intraoperative processes.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic V.

Hounsfield Unit-Calculated Bone Mineral Density Loss Following Combat-Related Lower Extremity Amputations

BACKGROUND

After combat-related lower extremity amputations, patients rapidly lose bone mineral density (BMD). As serial dual x-ray absorptiometry (DXA) scans are rarely performed in this setting, it is difficult to determine the timeline for bone loss and recovery or the role of interventions. However, a strong correlation has been demonstrated between DXA BMD and computed tomography (CT) signal attenuation. We sought to leverage multiple CT scans obtained after trauma to develop a predictive model for BMD after combat-related lower extremity amputations.

METHODS

We reviewed amputations performed within the United States military between 2003 and 2016 in patients with multiple CT scans. We collected pertinent clinical information, including amputation level(s), complications, and time to weight-bearing. The primary outcome measure was the development of low BMD, estimated in Hounsfield units (HU) from CT scans with use of a previously validated method. One hundred and twenty-eight patients with 613 femoral neck CT scans were available for analysis. A least absolute shrinkage and selection operator (LASSO) multiple logistic regression analysis was applied to determine the effects of modifiable and non-modifiable variables on BMD. A random-effects model was applied to determine which factors were most predictive of low BMD and to quantify their effects.

RESULTS

Both amputated and non-amputated extremities demonstrated substantial BMD loss, which stabilized approximately 3 years after the injury. Loss of BMD followed a logarithmic pattern, stabilizing after 1,000 days. On average, amputated limbs lost approximately 100 HU of BMD after 1,000 days. Other factors identified by the mixed-effects model included nonambulatory status (-33.5 HU), age at injury (-3.4 HU per year), surgical complications delaying weight-bearing (-21.3 HU), transtibial amputation (20.9 HU), and active vitamin-D treatment (-19.7 HU).

CONCLUSIONS

Patients with combat-related lower extremity amputations experience an initially rapid decline in BMD in both intact and amputated limbs as a result of both modifiable and non-modifiable influences, including time to walking, amputation level, surgical complications, and age. The paradoxical association of vitamin-D supplementation with lower HU likely reflects this treatment being assigned to patients with low BMD. This model may assist with clinical decision-making prior to performing lower extremity amputation and also may assist providers with postoperative decision-making to optimize management for prophylaxis against osteoporosis.

LEVEL OF EVIDENCE

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Imaging in inflammatory arthritis: progress towards precision medicine

Imaging techniques such as ultrasonography and MRI have gained ground in the diagnosis and management of inflammatory arthritis, as these imaging modalities allow a sensitive assessment of musculoskeletal inflammation and damage. However, these techniques cannot discriminate between disease subsets and are currently unable to deliver an accurate prediction of disease progression and therapeutic response in individual patients. This major shortcoming of today's technology hinders a targeted and personalized patient management approach. Technological advances in the areas of high-resolution imaging (for example, high-resolution peripheral quantitative computed tomography and ultra-high field MRI), functional and molecular-based imaging (such as chemical exchange saturation transfer MRI, positron emission tomography, fluorescence optical imaging, optoacoustic imaging and contrast-enhanced ultrasonography) and artificial intelligence-based data analysis could help to tackle these challenges. These new imaging approaches offer detailed anatomical delineation and an in vivo and non-invasive evaluation of the immunometabolic status of inflammatory reactions, thereby facilitating an in-depth characterization of inflammation. By means of these developments, the aim of earlier diagnosis, enhanced monitoring and, ultimately, a personalized treatment strategy looms closer.

Computer-aided design combined with 3D-printed osteotomy guide-assisted derotational distal femoral osteotomy for treating recurrent patellar dislocation with increased femoral anteversion angle: a retrospective study

PURPOSE

Derotational distal femoral osteotomy (DDFO) has good clinical outcomes for the treatment of the recurrent patellar dislocation combined with increased femoral anteversion angle (FAA). Currently, there is no uniform surgical technique. The purpose of this study was to evaluate the safety and efficacy of computer-aided design (CAD) combined 3D-printed osteotomy guide-assisted DDFO for treating these patients.

METHODS

In a retrospective study of 36 patients with recurrent patellar dislocation (RPD) from December 2017 to December 2020, all patients had increased FAA and underwent DDFO assisted by CAD combined with a 3D-printed osteotomy guide. Patients' radiological parameters were used to assess the correction of increased femoral torsion and preoperative and postoperative subjective scores were recorded to evaluate the knee function. Complications were recorded to determine the safety of the surgery.

RESULT

A total of 36 knees were included in this study, with a mean follow-up time of 32.6 ± 8.1 months. The mean age of the patients was 24.9±4.4 years and all patients experienced patellar dislocation preoperatively with a mean of 5.7±3.2 times. The patients' femoral anteversion angle decreased from 35.03±3.05° preoperatively to 14.80±0.87°, and the TT-TG distance decreased from 20.03±1.27 mm preoperatively to 19.22±1.22 mm. The hip-knee-ankle (HKA) angle and Insall-Salvatti index were not significantly different postoperatively compared to preoperatively. The knee function scores and visual analogue scale at the last follow-up were significantly improved compared to the preoperative scores. No major complications such as redislocation, nonunion, fixation or graft failure, or infection were observed in any patients.

CONCLUSION

Computer-aided design combined with 3D-printed osteotomy guide-assisted derotational distal femoral osteotomy could correct the increased anterior femoral torsion and demonstrate good results. There were no patients experienced re-dislocation during follow-up period and the overall complication rate is low.

Computed Tomography Scan Versus Saline Load Test for Detection of Traumatic Shoulder Arthrotomy: A Cadaveric Study

OBJECTIVES

Traumatic shoulder arthrotomy (TSA) is a rare injury that is commonly detected through saline load test (SLT). There are no studies that have studied the ability of computed tomography (CT) scan to detect a TSA. The purpose of this study is to determine the ability of CT scan to detect a TSA and compare it with the SLT.

METHODS

Twelve cadaveric shoulders were included in the study. Before intervention, a CT scan was conducted to determine presence of intra-articular air. After confirmation that no air was present, an arthrotomy was made at the anterior or posterior portal site. A CT was obtained postarthrotomy to evaluate for intra-articular air. Each shoulder then underwent an SLT to assess the sensitivity of SLT and the volume needed for extravasation.

RESULTS

Twelve shoulders were included after a pre-intervention CT scan. Six shoulders received an arthrotomy through the anterior portal and six shoulders received an arthrotomy through the posterior portal. After the arthrotomy, air was visualized on CT scan in 11 of the 12 shoulders (92%). All 12 shoulders demonstrated extravasation during SLT. The mean volume of saline needed for extravasation was 29 mL with an SD of 10 and range of 18-50 mL.

CONCLUSIONS

CT scan is a sensitive modality (sensitivity of 92%) for detection of TSA. In comparison, SLT is more sensitive (sensitivity of 100%) and outperforms CT scan for the diagnosis of TSA in a cadaveric model. Further research is needed to solidify the role that CT imaging has in the diagnosis of TSAs.

The influence of pre-operative Computed Tomography (CT) on surgical approach and fixation for fractures of the tibial plateau

Background

It is well known that a computed tomography (CT) scan improves the classification of tibial plateau fractures (TPF) compared with radiographs. However, it is less clear how this translates into clinical practice. The aim of this study is to establish to what extent a pre-operative CT scan alters the approach, setup and fixation choice in TPF compared to radiographs.

Methods

50 consecutive TPF with a preoperative CT and radiographic imaging available, were assessed by 4 consultant surgeons. First, anonymised radiographs were classifying according to the column classification and the planned setup, approach, and fixation technique documented. At a 1-month interval, randomised matched CT scans were assessed and the same data collected. A tibial plateau disruption score (TPDS) was derived for all 4 quadrants (no injury = 0, split = 1, split/depression = 2 and depression = 3). Radiograph and CT TPDS were assessed using an unpaired T-test.

Results

26 female and 24 male patients, mean age 50.3, were included. Mean TPDS on radiographs and CT scans were 2.77 and 3.17 respectively. A significantly higher CT TPDS, of 0.4 (95%CI 0.10-0.71)[P = 0.0093] was observed, demonstrating that radiographs underestimate the extent of injury. The surgical approach changed in 28.5% of cases, thus influencing a change in the patient setup in theatre in 27% of cases. Identification of fractures within a column changed in 34% of cases. A high intra-observer reliability was observed when surgeons were asked to repeat their assessment in a third round at a further one month interval.

Conclusion

A pre-operative CT scan has a significant effect on the approach required to fix TPF. This therefore influences the setup of the patient and can justifiably be requested as part of pre-operative planning.

Glenoid Track Assessment at Imaging in Anterior Shoulder Instability: Rationale and Step-by-Step Guide

Anterior shoulder dislocation is the most common form of joint instability in humans, usually resulting in soft-tissue injury to the glenohumeral capsuloligamentous and labral structures. Bipolar bone lesions in the form of fractures of the anterior glenoid rim and posterolateral humeral head are often associated with anterior shoulder dislocation and can be a cause or result of recurrent dislocations. Glenoid track assessment is an evolving concept that incorporates the pathomechanics of anterior shoulder instability into its management. Currently widely endorsed by orthopedic surgeons, this concept has ramifications for prognostication, treatment planning, and outcome assessment of anterior shoulder dislocation. The glenoid track is the contact zone between the humeral head and glenoid during shoulder motion from the neutral position to abduction and external rotation. Two key determinants of on-track or off-track status of a Hill-Sachs lesion (HSL) are the glenoid track width (GTW) and Hill-Sachs interval (HSI). If the GTW is less than the HSI, an HSL is off track. If the GTW is greater than the HSI, an HSL is on track. The authors focus on the rationale behind the glenoid track concept and explain stepwise assessment of the glenoid track at CT or MRI. Off-track to on-track conversion is a primary goal in stabilizing the shoulder with anterior instability. The key role that imaging plays in glenoid track assessment warrants radiologists' recognition of this concept along with its challenges and pitfalls and the production of relevant and actionable radiology reports for orthopedic surgeons-to the ultimate benefit of patients. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available through the Online Learning Center.

Prevalence of intra-articular mineralization on knee computed tomography: the multicenter osteoarthritis study

OBJECTIVE

The aim of this work was to report the prevalence of computed tomography (CT)-detected intra-articular mineralization.

DESIGN

We included participants from the Multicenter Osteoarthritis (MOST) Study. At the 12th year visit of the MOST study, bilateral knee CTs were first obtained. All participants also had posteroanterior and lateral radiographs of bilateral knees and completed standard questionnaires. Knee radiographs were assessed for Kellgren & Lawrence grade (KLG) and radiographic evidence of intra-articular mineralization. CT images were scored using the Boston University Calcium Knee Score (BUCKS) for cartilage, menisci, ligaments, capsule, and vasculature. Prevalence of intra-articular mineralization was computed for the total sample, and stratified by age, sex, race, Body Mass Index (BMI), presence of frequent knee pain, and KLG. We also determined distribution of mineralization in the cartilage and meniscus, and co-localization.

RESULTS

4140 bilateral knees from 2070 participants were included (56.7% female, mean age 61.1 years, mean BMI: 28.8 kg/m2). On radiographs 240 knees (5.8%) had intraarticular mineralization, while CT-detected mineralization was present in 9.8% of knees. Prevalence of hyaline articular and meniscus mineralization increased with age and KL grade, and was similar by sex, BMI categories, and comparable in subjects with and without frequent knee pain. Mineralization tended to be ubiquitous in the joint, most commonly involving all three (medial/lateral tibiofemoral and patellofemoral) compartments (3.1%), while the patellofemoral compartment was the most involved compartment in isolation (1.4%).

CONCLUSIONS

CT of the knee provides greater visualization of intra-articular mineralization than radiographs and allows better localization of the crystal deposition within the joint. Further studies should focus on the co-localization of intra-articular crystal deposition and corresponding magnetic resonance imaging (MRI)-features of knee osteoarthritis (OA).

Projected Lifetime Cancer Risk Associated With Intraoperative Computed Tomography for Lumbar Spine Surgery

STUDY DESIGN

Retrospective cross-sectional study.

OBJECTIVE

(1) To determine the incremental increase in intraoperative ionizing radiation conferred by computed tomography (CT) as compared with conventional radiography; and (2) to model different lifetime cancer risks contextualized by the intersection between age, sex, and intraoperative imaging modality.

SUMMARY OF BACKGROUND DATA

Emerging technologies in spine surgery, like navigation, automation, and augmented reality, commonly utilize intraoperative CT. Although much has been written about the benefits of such imaging modalities, the inherent risk profile of increasing intraoperative CT has not been well evaluated.

MATERIALS AND METHODS

Effective doses of intraoperative ionizing radiation were extracted from 610 adult patients who underwent single-level instrumented fusion for lumbar degenerative or isthmic spondylolisthesis from January 2015 through January 2022. Patients were divided into those who received intraoperative CT (n=138) and those who underwent conventional intraoperative radiography (n=472). Generalized linear modeling was utilized with intraoperative CT use as a primary predictor and patient demographics, disease characteristics, and preference-sensitive intraoperative considerations ( e.g. surgical approach and surgical invasiveness) as covariates. The adjusted risk difference in radiation dose calculated from our regression analysis was used to prognosticate the associated cancer risk across age and sex strata.

RESULTS

(1) After adjusting for covariates, intraoperative CT was associated with 7.6 mSv (interquartile range: 6.8-8.4 mSv; P <0.001) more radiation than conventional radiography. (2) For the median patient in our population (a 62-year-old female), intraoperative CT use increased lifetime cancer risk by 2.3 incidents (interquartile range: 2.1-2.6) per 10,000. Similar projections for other age and sex strata were also appreciated.

CONCLUSIONS

Intraoperative CT use significantly increases cancer risk compared with conventional intraoperative radiography for patients undergoing lumbar spinal fusions. As emerging technologies in spine surgery continue to proliferate and leverage intraoperative CT for cross-sectional imaging data, strategies must be developed by surgeons, institutions, and medical technology companies to mitigate long-term cancer risks.

Decision-Making and Management of Tarsal Coalition in the Young Adult Patient: A Critical Analysis Review

» Tarsal coalitions most commonly affect the calcaneonavicular and talocalcaneal joints in up to 13% of the general population. They alter the mechanics of the subtalar joint, limiting inversion and eversion, and place excessive stress on neighboring joints causing pain, recurrent ankle sprains, and/or progressive pes planus during the adolescent growth spurt.» While many coalitions are identified on radiographs, advanced imaging with computed tomography or magnetic resonance imaging is sometimes required. These advanced imaging modalities also serve an essential role for surgical planning to quantify coalition involvement, identify fibrous or cartilaginous coalitions, and aid in determining the degree of deformity within the foot.» Surgical treatment is reserved for feet with persistent activity-related pain not relieved by prolonged attempts at nonoperative management, which include nonsteroidal anti-inflammatory drugs, shoe orthotics, and periods of non-weight-bearing in a cast. These conservative modalities may be successful in up to 85% of cases.» For adolescent patients, recent surgical options attempt to avoid arthrodesis and focus on coalition resection and interposition grafting with or without deformity correction. The ultimate decision is based on the location of the pain, the size and histology of the coalition, the health of the posterior subtalar facet, the degree of flatfoot deformity, and the presence of degenerative changes in the subtalar and/or adjacent joints.» While many studies focus on subtalar motion and gait kinematics, the critical outcomes remain pain relief and future need for arthrodesis, which may be related not only to resection of the coalition but assessment of deformity, including after the resection has been performed.

Implementing 3D fluoroscopy in the management of tibial plateau fractures: Shorter hospitalization and decline in revision surgery, but increase in the duration of surgery and radiation exposure

BACKGROUND

Intraoperative 3D fluoroscopy (3DRX) is increasingly used in fracture management instead of conventional fluoroscopy (RX), but its effect on the treatment and outcome of tibial plateau fractures (TFs) is not well known. This study aims to evaluate whether the use of 3DRX in the treatment of tibial plateau fractures reduces the number of revision surgeries.

METHODS

This retrospective cohort study includes all patients who underwent surgical treatment for TF in a single center from 2014 to 2018. Patient-, fracture-, and treatment characteristics were compared between the 3DRX and RX subgroups. The primary endpoint was the number of patients requiring revision surgery. Secondary endpoints were surgery duration, hospital length of stay, radiation exposure, postoperative complications, and secondary total knee arthroplasty.

RESULTS

Eighty-seven patients were included, of which 36 were treated with 3DRX. Three patients in the RX group required revision surgery, while no revision surgery was performed in the 3DRX group (p = 0.265). The use of 3DRX resulted in significantly more intraoperative adjustments (25% versus 6%; p = 0.024) and an increase in surgery duration (by average of 28 min, p = 0.001), without a significant increase in postoperative wound infections (12% versus 19%; p = 0.374) or fracture-related infections (2% versus 2.8%; p = 0.802). The 3DRX group had an average radiation exposure of 7,985 mGy versus 1,273 mGy in the RX group (p<0.001). The hospital length of stay was 1 day shorter in the 3DRX group (5 days versus 4 days; p = 0.058).

CONCLUSIONS

Implementing 3DRX in treating TFs improves the assessment of fracture alignment and implant position perioperatively, resulting in more intraoperative corrections and no revision surgeries within 6 weeks postoperatively. However, using 3DRX significantly increases perioperative radiation exposure and surgery duration without a significant rise in postoperative infections and a shorter hospital length of stay.

Arthroscopic versus open cancellous bone grafting for scaphoid delayed/nonunion in adults (SCOPE-OUT): study protocol for a randomized clinical trial

BACKGROUND

Scaphoid non-union results in pain and decreased hand function. Untreated, almost all cases develop degenerative changes. Despite advances in surgical techniques, the treatment is challenging and often results in a long period with a supportive bandage until the union is established. Open, corticocancellous (CC) or cancellous (C) graft reconstruction and internal fixation are often preferred. Arthroscopic assisted reconstruction with C chips and internal fixation provides minimal trauma to the ligament structures, joint capsule, and extrinsic vascularization with similar union rates. Correction of deformity after operative treatment is debated with some studies favouring CC, and others found no difference. No studies have compared time to union and functional outcomes in arthroscopic vs. open C graft reconstruction. We hypothesize that arthroscopic assisted C chips graft reconstruction of scaphoid delayed/non-union provides faster time to union, by at least a mean 3 weeks difference.

METHODS

Single site, prospective, observer-blinded randomized controlled trial. Eighty-eight patients aged 18-68 years with scaphoid delayed/non-union will be randomized, 1:1, to either open iliac crest C graft reconstruction or arthroscopic assisted distal radius C chips graft reconstruction. Patients are stratified for smoking habits, proximal pole involvement and displacement of > / < 2 mm. The primary outcome is time to union, measured with repeated CT scans at 2-week intervals from 6 to 16 weeks postoperatively. Secondary outcomes are Quick Disabilities of the Arm, Shoulder and Hand (Q-DASH), visual analogue scale (VAS), donor site morbidity, union rate, restoration of scaphoid deformity, range of motion, key-pinch, grip strength, EQ5D-5L, patient satisfaction, complications and revision surgery.

DISCUSSION

The results of this study will contribute to the treatment algorithm of scaphoid delayed/non-union and assist hand surgeons and patients in making treatment decisions. Eventually, improving time to union will benefit patients in earlier return to normal daily activity and reduce society costs by shortening sick leave.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05574582. Date first registered: September 30, 2022. Items from the WHO trial registry are found within the protocol.

Evaluation of the safety and efficacy of the fully automated active robotic system in robotic assisted total knee arthroplasty

Background

Use of semi-active and active robotic system for performing Total Knee Arthroplasty (TKA) is increasing. The novel fully automated active robotic system performs milling of the bone surfaces with a high speed burr. The aim of the current study was to assess the safety and efficacy of the system in robotic assisted TKA (RA-TKA).

Materials and methods

A single center clinical trial was conducted following 30 knees undergoing active RA-TKA for 6 months. Inclusion criteria were patients undergoing RA-TKA for end stage arthritis. Patients undergoing conventional TKA and revision TKA were excluded from the study. Sample size was estimated to be 28 patients with α error of 0.05 and β error of 0.2 with power of study being 80. A pre-defined list of RA-TKA adverse events was employed to study the safety of the system. Efficacy was judged by comparing the planned versus achieved Implant size, alignment and limb alignment on post-operative radiographs. The post-operative clinical evaluation was done by an independent observer who was not part of the operating team. The primary safety and efficacy hypothesis was tested using a one sided Exact binomial test. The p value < 0.05 was considered significant.

Results

Pre-defined adverse events did not occur in any of the 30 RA-TKA (statistically significant p value < 0.001). The implant size accuracy was 100% (30 out of 30 knees) for femoral component and 96.67% (29 out of 30 knees) for tibial component (statistically significant, Chi-squared test, p value 0.0105 and 0.0461 respectively). The implant position and limb alignment was accurate in 100% of patients (p value < 0.001).

Conclusion

Early experience of the use of fully automated active robotic system in TKA shows that it is safe and also is effective in achieving accurate implant size and implant/limb alignment.

Grid and Image Intensifier Improve Arthroscopic ACL Tunnel Position and Patient-Reported Outcomes

Purpose

To evaluate the accuracy in the femoral and tibial tunnel placement after the use of fluoroscopy along with an indigenously designed grid method to assist in arthroscopic anterior cruciate ligament reconstruction as compared with the tunnel placement without using them and to validate the findings with computed tomography scan performed postoperatively along with assessing the functional outcome at a minimum of 3 years of follow-up.

Methods

This was a prospective study conducted on patients who underwent primary anterior cruciate ligament reconstruction. Patients were included and segregated into a nonfluoroscopy (group B) and a fluoroscopy group (group A), and both had postoperative computed tomography scans so that femoral and tibial tunnel position could be evaluated. Scheduled follow-up occurred 3, 6, 12, 24, and 36 months' postoperatively. Patients were evaluated objectively with the Lachman test, measurement of range of motion, and functional outcome using patient-reported outcome measures, i.e., Tegner Lysholm Knee score, Knee injury and Osteoarthritis Outcome Score, and International Knee Documentation Committee subjective knee score.

Results

A total of 113 subjects were included. There were 53 in group A and 60 in group B. The average location of femoral tunnel showed significant differences between the 2 groups. However, the variability in femoral tunnel location was significantly lower in group A as compared with group B for proximal-distal planes only. The average location of the tibial tunnel as per the grid of Bernard et al. showed significant differences in both the planes. The variability in tibial tunnel was greater in the medial-lateral plane as compared with the anterior-posterior plane. There was a statistically significant difference in mean value of the 3 scores among the 2 groups. The variability of the scores was greater in group B as compared with group A. None of the patient was reported as a failure.

Conclusions

The results of our study suggests that fluoroscopy-guided positioning using a grid technique increases the accuracy of anterior cruciate ligament tunnel positioning with decreased variability and is associated with better patient-reported outcomes 3 years after surgery compared with tunnel positioning using landmarks.

Level of Evidence

Level II, prospective, comparative therapeutic trial.

Knowledge of radiation exposure associated with common trauma imaging modalities among orthopaedic surgeons, emergency medicine physicians, and general surgeons in the United States

BACKGROUND

Few contemporary studies have assessed physicians' knowledge of radiation exposure associated with common imaging studies, especially in trauma care. The purpose of this study was to assess the knowledge of physicians involved in caring for trauma patients regarding the effective radiation doses of musculoskeletal (MSK) imaging studies routinely utilized in the trauma setting.

METHODS

An electronic survey was distributed to United States orthopaedic surgery, general surgery, and emergency medicine (EM) residency programs. Participants were asked to estimate the radiation dose for common imaging modalities of the pelvis, lumbar spine, and lower extremity, in terms of chest X-ray (CXR) equivalents. Physician estimates were compared to the true effective radiation doses. Additionally, participants were asked to report the frequency of discussing radiation risk with patients.

RESULTS

A total of 218 physicians completed the survey; 102 (46.8%) were EM physicians, 88 (40.4%) were orthopaedic surgeons, and 28 (12.8%) were general surgeons. Physicians underestimated the effective radiation doses of nearly all imaging modalities, most notably for pelvic computed tomaography (CT) (median 50 CXR estimation vs. 162 CXR actual) and lumbar CT (median 50 CXR estimation vs. 638 CXR actual). There was no difference between physician specialties regarding estimation accuracy (P=0.133). Physicians who regularly discussed radiation risks with patients more accurately estimated radiation exposure (P=0.007).

CONCLUSION

The knowledge among orthopaedic and general surgeons and EM physicians regarding the radiation exposure associated with common MSK trauma imaging is lacking. Further investigation with larger scale studies is warranted, and additional education in this area may improve care.

Pediatric Sports Trauma

Pediatric foot and ankle fractures are common in athletic participation. Treatment of pediatric sports trauma must take into account the unique challenges this population presents, and aim to minimize long-term complications. Given the excellent remodeling potential of pediatric bone, conservative treatment can often be used. However, a thorough understanding of physeal anatomy, fracture patterns, and biomechanics is needed to guide treatment choice and determine when surgical intervention is warranted.

In Vivo Metacarpophalangeal Joint Kinematics After Silicone Implant Arthroplasty in Patients With Rheumatoid Arthritis

PURPOSE

The aim of this study was to determine the potential mechanism of implant fracture using 3-dimensional motion analysis of patients with rheumatoid arthritis.

METHODS

Active flexion motion in 9 hands (34 fingers) of 6 female patients with rheumatoid arthritis who previously underwent hinged silicone metacarpophalangeal joint arthroplasty was examined using 4-dimensional computed tomography. Positions of the proximal phalanges relative to the metacarpals were quantified using a surface registration method. The deformation of the silicone implant was classified in the sagittal plane in the maximum flexion frame. The longitudinal bone axis of the proximal phalanx and the helical axis of the proximal phalanx were evaluated in 3-dimensional coordinates based on the hinge of the silicone implant.

RESULTS

Nineteen fingers were classified into group 1, in which the silicone implant moved volarly during flexion without buckling of the distal stem. Twelve fingers were classified into group 2, in which the distal stem of the silicone implant buckled. Three fingers were classified into group 3, in which the base of the distal stem had already fractured. Quantitatively, the longitudinal bone axes of the proximal phalanges were displaced from dorsal to volar in the middle stage of flexion and migrated in the proximal direction in the late phase of flexion. The helical axes of the proximal phalanges were located on the dorsal and proximal sides of the hinge, and these tended to move in the volar and proximal directions as the metacarpophalangeal joint flexed.

CONCLUSIONS

Volar and proximal translation of the proximal phalange was observed on 4-dimensional computed tomography.

CLINICAL RELEVANCE

Proximal displacement of the bone axis late in flexion appears to be a contributing factor inducing implant fractures, because the pistoning motion does not allow the implant to move in the proximal direction.

Advances in Bone Joint Imaging-Metal Artifact Reduction

Numerous types of metal implants have been introduced in orthopedic surgery and are used in everyday practice. To precisely evaluate the postoperative condition of arthroplasty or trauma surgery, periprosthetic infection, and the loosening of implants, it is important to reduce artifacts induced by metal implants. In this review, we focused on technical advances in metal artifact reduction using digital tomosynthesis, computed tomography, and magnetic resonance imaging. We discussed new developments in diagnostic imaging methods and the continuous introduction of novel technologies to reduce metal artifacts; however, these innovations have not yet completely removed metal artifacts. Different algorithms need to be selected depending on the size, shape, material and implanted body parts of an implant. Future advances in metal artifact reduction algorithms and techniques and the development of new sequences may enable further reductions in metal artifacts even on original images taken previously. Moreover, the combination of different imaging modalities may contribute to further reductions in metal artifacts. Clinicians must constantly update their knowledge and work closely with radiologists to select the best diagnostic imaging method for each metal implant.

Arc center distance as a novel quantitative radiographic parameter for volar Barton fractures

PURPOSE

The aims of this study were to investigate conventional radiographic parameters and introduce a novel parameter (arc center distance, ACD) for volar Barton fractures.

METHODS

Twenty-four cases of volar Barton fracture were retrospectively analyzed. We measured volar tilt angle (VTA), anteroposterior distance (APD), teardrop angle (TDA), and capitate-to-axis-of-radius distance (CARD) on lateral plain radiographs. The ACD was measured on the sagittal images of computed tomography scans. VTAs, APDs, TDAs, and CARDs were compared between the fractured and normal contralateral wrist. The area under the receiver operating characteristic curve was calculated for each parameter.

RESULTS

TDAs did not differ significantly between the fractured wrists and the controls. On the other hand, VTAs, APDs, and CARDs were all significantly greater in the fractured wrists (mean values were 17.25°, 20.70 mm, and - 3.40 mm, respectively). The area under the curve value was highest (0.943) for the ACD. When a cutoff value of 1.02 mm was used as a threshold, a sensitivity of 100% and specificity of 80.95% were achieved.

CONCLUSIONS

The mean values of conventional parameters (VTA, APD, TDA and CARD) in volar Barton fractures were presented. The ACD can be useful parameter for quantitatively evaluating volar Barton fractures.

Usefulness of digital tomosynthesis in diagnosing cervical ossification of the posterior longitudinal ligament: a comparative study with other imaging modalities

PURPOSE

The diagnosis and classification of ossification of the posterior longitudinal ligament (OPLL) can be difficult with radiography alone; therefore, computed tomography (CT) is also usually performed. There are many reports on the usefulness of digital tomosynthesis (DTS) for image analysis in orthopedics. This study aimed to compare the accuracy of DTS with radiography and CT for the diagnosis and classification of cervical OPLL (C-OPLL).

MATERIALS AND METHODS

We included 31 patients with OPLL and 30 with cervical spondylotic myelopathy. The patients' cervical spine radiography, DTS, and CT images were each evaluated twice by three specialists and three residents.

RESULTS

In the intra-observer reliability study, there was one observer with a fair level of kappa values for radiography and DTS among three residents. The kappa values for CT were the best for all observers. In the inter-observer reliability study, the interclass correlation coefficient (ICC) values were high for both diagnosis and classification by specialists at the almost perfect level for all three imaging modalities. On the other hand, the ICC values for both diagnosis and classification for radiography by the residents were lower than those for DTS and CT.

CONCLUSIONS

This study revealed that DTS may be an alternative to CT for the diagnosis and classification of C-OPLL by specialists. Caution should be exercised in diagnosing and classifying C-OPLL using radiography and DTS by residents, and the use of CT is recommended.

Multi-planar instability, laxity and reduced knee flexion during the support phase of walking are determinants of return to sports

Background: After anterior cruciate ligament reconstruction, some patients are not recommended to return to high-level physical activity because they fail to pass return-to-sports tests. The kinematic difference between these patients and those who pass the return-to-sports tests is unclear.

Methods: Eighty-two patients who received anatomic single-bundle anterior cruciate ligament (ACL) reconstruction for unilateral ACL injury underwent return-to-sport tests during a hospital visit at a minimum of 9 months (9–11 months) of follow-up. Fifteen patients who passed the return-to-sports tests (RTS group) and fifteen patients who did not (NRTS group) were randomly selected to perform a treadmill walk under dual-fluoroscopic imaging system surveillance for a 6 degrees of freedom kinematic evaluation.

Results: Of the 82 patients, 53 passed the return-to-sports tests 9 months after surgery, with a return-to-sports rate of 64.6%. In the stance phase, the NRTS group had a larger anterior tibial translation (1.00 ± 0.03 mm vs. 0.76 ± 0.03 mm, p = 0.001), a larger lateral tibial movement (1.61 ± 0.05 mm vs. 0.77 ± 0.05 mm, p < 0.001), a larger distal tibial displacement (−3.09 ± 0.05 mm vs. −2.69 ± 0.05 mm, p < 0.001), a smaller knee flexion angle (6.72 ± 0.07° vs. 8.34 ± 0.07°, p < 0.001), a larger varus angle (−0.40 ± 0.03°VS. -0.01 ± 0.03°, p < 0.001) and a larger external rotation angle (1.80 ± 0.05° vs. 1.77 ± 0.05°, p < 0.001) than the RTS group. The maximum anterior tibial translation of the NRTS group is also larger than that of the RTS group (3.64 ± 0.42 mm vs. 3.03 ± 0.59 mm, p = 0.003).

Conclusion: Compared with patients passing RTS tests, those who fail to pass show significant anterior, lateral, and rotational instability; knee laxity; and reduced flexion angle of the knee in the support phase during walking, which may be the possible factors hindering a return to sports.

Diagnostic Performance and Advanced Imaging Reduction With Digital Tomosynthesis in Scaphoid Fracture Management

BACKGROUND

Management of scaphoid fractures often requires advanced imaging to achieve accurate diagnoses and appropriate treatment. Digital tomosynthesis (DTS) is a cross-sectional imaging modality that may be used to substitute magnetic resonance imaging or computed tomographic scans. The purpose of this study is to: (1) determine the diagnostic accuracy of DTS in occult scaphoid fractures; and (2) report on the reduction of other advanced imaging when using DTS.

METHODS

From May 2014 to October 2017, the charts of all patients who underwent scaphoid tomogram were retrospectively reviewed. The diagnostic accuracy of DTS for occult fracture was compared with 2-week follow-up plain films. To measure the reduction in utilization of advanced imaging, it was determined whether DTS eliminated the need for advanced imaging by providing adequate information regarding the clinical question.

RESULTS

A total of 78 patients underwent scaphoid tomography in this time frame: 39 for occult fracture, 33 for fracture union, 5 for fracture morphology, and 1 for hardware positioning. For the detection of occult fracture, DTS had a sensitivity of 100%, specificity of 83%, positive predictive value of 64%, and negative predictive value of 100%. Advanced imaging was not used in 35 of the remaining 39 patients based on the results obtained by DTS. In patients who did receive advanced imaging, 83% of tomograms provided conclusive diagnostic information.

CONCLUSIONS

Digital tomosynthesis increases the diagnostic sensitivity of occult scaphoid fractures, reducing unnecessary immobilization and advanced imaging. Digital tomosynthesis provides clinical detail beyond plain film, which reduces the need to obtain advanced imaging when assessing union, fracture pattern, and hardware placement.

A comparison of cone beam computed tomography, standard computed tomography and plain radiographs in the evaluation of medial epicondyle humerus fractures

The ideal technique to measure medial epicondyle humerus fracture displacement minimizes radiation exposure while maximizing measurement accuracy and reliability. This study compares the radiation exposure and accuracy of displacement measurements of the four-view X-ray examination (XR), computed tomography (CT) and in-clinic cone-beam CT (CBCT). A cadaveric humerus underwent medial epicondyle osteotomy. The fragment was fixed to the humerus at clinically relevant displacements (6 to 18 mm). Dosimeters were placed around the distal humerus and simulating thyroid location. XR, CT and CBCT were performed at each displacement. Four pediatric orthopedists measured the maximum linear displacement on each XR and 3D reconstruction of the CT and CBCT images. Focal (elbow location) and thyroid radiation exposure was compared between modalities. Intra- and interclass correlation coefficients (ICC) for displacement measurements were determined. Mean focal radiation exposures for XR, CT and CBCT were 0.008, 2.061 and 0.478 rad, respectively (P = 0.001). Exposures 10 inches from the elbow for XR, CT and CBCT were 0.001, 0.066 and 0.010 rad, respectively (P = 0.006). At 12 inches, there was no significant difference in exposure between XR and CBCT ( P  = 0.114). Intra- and interobserver reliabilities were excellent for all measures, except lateral x-ray. CBCT and CT had significantly less deviation from the actual displacement compared to XR ( P  < 0.05). In-office CBCT of the elbow exposes patients to significantly less radiation than conventional CT. All X-ray images (except lateral), CT and CBCT had equal reliability in evaluating medial epicondyle fractures, which contrasts with previous evidence.

Global Irradiation in Children Treated for Hydrocephalus and Its Change over Time—A Single Institutional Analysis

Radiation exposure early in life is associated with greater incidences of malignancy. Our goal was to quantify radiation exposure in shunt-treated hydrocephalus patients and study changes in the diagnostic modalities used. A single-center, retrospective analysis was performed, and 41 children treated for hydrocephalus using an adjustable ventriculoperitoneal shunt were identified. Diagnostics associated with hydrocephalus and other comorbidities were analyzed and radiation exposure was calculated. During 330.09 total shunt years, patients were exposed to a mean hydrocephalus-associated radiation dose of 3.93 mSv (range: 0–24.38 mSv), which amounted to a mean rate of 0.49 mSv per shunt year, respectively. Radiation exposure was greatest after shunt insertion in the first year of life. A continuous change from CT scans to MRIs could be seen over the study period, such that patients who underwent shunt insertion after 2017 were not exposed to additional hydrocephalus-associated radiation during their first year of life. Nevertheless, our patients, and a few individuals especially, seemed to be at higher risk for radiation sequelae. Our results suggest that CT scans should be substituted with MRIs, which decrease overall radiation exposure and can lead to zero additional radiation exposure during the first year of life after shunt insertion.

Effect of Preoperative MRI Coracoid Dimensions on Postoperative Outcomes of Latarjet Treatment for Anterior Shoulder Instability

Background:

Preoperative coracoid dimensions may affect the size of the bone graft transferred to the glenoid rim and thus the postoperative outcomes of Latarjet coracoid transfer.

Purpose:

To determine the effect of coracoid length and width as measured on preoperative magnetic resonance imaging (MRI) on outcomes after Latarjet treatment of anterior shoulder instability.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Included were patients who underwent primary Latarjet surgery between 2009 and 2019 and had preoperative MRI scans and minimum 2-year postoperative outcomes. Longitudinal coracoid length was measured on axial MRI sequences as the distance from the coracoclavicular ligament insertion to the distal tip. Comparisons were made between shorter and longer coracoids and between narrower and wider coracoids. The outcomes of interest were recurrent instability, reoperation, complications, return to sport (RTS), and American Shoulder and Elbow Surgeons (ASES) score. Independent-samples t test, Mann-Whitney test, chi-square test, and Fisher exact test were used to compare outcomes between groups, and univariate correlation coefficients were calculated to evaluate the relationships between demographics and coracoid dimensions.

Results:

Overall, 56 patients were included (mean age, 28.4 years). The mean ± SD coracoid length was 21.6 ± 2.4 mm and width 10.0 ± 1.0 mm. Relative to patients with a longer coracoid (≥22 mm; n = 26), patients with a shorter coracoid (<22 mm; n = 30) had similar rates of recurrent instability (shorter vs longer; 6.7% vs 3.8%), complications (10.0% vs 15.4%), reoperation (3.3% vs 7.7%), and RTS (76.5% vs 58.8%) and similar postoperative ASES scores (85.0 vs 81.6) ( P ≥ .05 for all). Likewise, relative to patients with a wider coracoid (≥10 mm; n = 27), patients with a narrower coracoid (<10 mm; n = 29) had similar prevalences of recurrent instability (narrower vs wider; 6.9% vs 3.7%), complications (17.2% vs 7.4%), reoperation (3.5% vs 7.4%), and RTS (66.7% vs 68.4%) and similar postoperative ASES scores (87.1 vs 80.0) ( P ≥ .05 for all).

Conclusion:

Patients undergoing Latarjet coracoid transfer had similar postoperative outcomes regardless of preoperative coracoid dimensions. These findings should be confirmed in a larger cohort before further clinical recommendations are made.

Precontouring Plates for MIS Bilateral Femur Osteosynthesis Using a Patient-Specific 3D Printed Model: A Case Report

CASE

A 27-year-old woman with increasing bilateral thigh pain and underlying diagnosis of dysosteosclerosis was diagnosed with bilateral impending pathological femur fractures. Both femurs exhibited abnormal morphology with bowing, thickened cortices, and narrow intramedullary canals. We planned minimally invasive prophylactic plate osteosynthesis. Computed tomography scans of both femora were obtained and used to generate 3-dimensional (3D) printed models. Osteosynthesis plates were precontoured to fit the 3D models and sterilized, and prophylactic fixation was performed using a minimally invasive submuscular technique.

CONCLUSION

3D printed models aided in precontouring fixation plates in a case with challenging bony anatomy, enabling minimally invasive surgery.

The Use of Computerized Tomography Scans in Elective Knee and Hip Arthroplasty—What Do They Tell Us and at What Risk?

The average background radiation exposure in the United States has nearly doubled over the previous quarter century, with almost all the increase derived from medical imaging. Nearly 2% of all cancers in the United States may be attributable to radiation from computerized tomography (CT) scans. Given the nondiagnostic nature of CT scans that are used in elective knee and hip arthroplasty today, special consideration should be given to the inherent risk of radiation exposure with routine use of this technology. Methods to decrease radiation exposure including modulating the settings of the CT machine and using alternative non-CT-based systems can decrease patient exposure to radiation from CT scans. The rapid evolution of CT technology in arthroplasty has allowed for expanded clinical applications, the benefits of which remain controversial.

Comparison of Simulated Low-Dose and Conventional-Dose CT for Preoperative Planning in Shoulder Arthroplasty

BACKGROUND

Shoulder computed tomography (CT) is commonly utilized in preoperative planning for total shoulder arthroplasty. Conventional-dose shoulder CT may expose patients to more ionizing radiation than is necessary to provide high-quality images for this procedure. The purpose of this study was to evaluate the utility of simulated low-dose CT images for preoperative planning using manual measurements and common preoperative planning software.

METHODS

Eighteen shoulder CT scans obtained for preoperative arthroplasty planning were used to generate CT images as if they had been acquired at reduced radiation dose (RD) levels of 75%, 50%, and 25% using a simulation technique that mimics decreased x-ray tube current. This technique was validated by quantitative comparison of simulated low-dose scans of a cadaver with actual low-dose scans. Glenoid version, glenoid inclination, and humeral head subluxation were measured using 2 commercially available software platforms and were also measured manually by 3 physicians. These measurements were then analyzed for agreement across RD levels for each patient. Tolerances of 5° of glenoid version, 5° of glenoid inclination, and 10% humeral head subluxation were used as equivalent for preoperative planning purposes.

RESULTS

At all RD levels evaluated, the preoperative planning software successfully segmented the CT images. Semiautomated software measurement of 25% RD images was within tolerances in 99.1% of measurements; for 50% RD images, within tolerances in 96.3% of measurements; and for 75% RD images, within tolerances in 100% of measurements. Manual measurements of 25% RD images were within these tolerances in 95.1% of measurements; for 50% RD images, in 98.8% of measurements; and for 75% RD images, in 99.4% of measurements.

CONCLUSIONS

Simulated low-dose CT images were sufficient for reliable measurement of glenoid version, glenoid inclination, and humeral head subluxation by preoperative planning software as well as by physician-observers. These findings suggest the potential for substantial reduction in RD in preoperative shoulder CT scans without compromising surgical planning.

CLINICAL RELEVANCE

The adoption of low-dose techniques in preoperative shoulder CT may lower radiation exposure for patients undergoing shoulder arthroplasty, without compromising image quality.

Supine leg press as an alternative to standing lunge in high-speed stereo radiography

The standing lunge is an activity commonly used to quantify in-vivo knee kinematics with fluoroscopy. The ability to perform the standing lunge varies between subjects and can necessitate movement accommodations to successfully complete the desired range of motion. We proposed a supine leg press as an alternative to the standing lunge that aimed to provide a similar evaluation of knee motion while increasing the measured range of motion. Tibiofemoral kinematics of 53 non-symptomatic adults (27 men, 26 women, 50.8 ± 7.0 yrs.) were calculated from the tracked high-speed stereo radiography (HSSR) images for supine leg press and standing lunge using CT-segmented bony geometries of the right lower limb. The supine leg press proved to be a useful alternative to the standing lunge while providing 46.2° greater range of motion in knee flexion. The difference in angle-matched kinematics across a 100° flexion range between the leg press and lunge was 0.70° in varus-valgus rotation, 1.5° in internal-external rotation, 1.0 mm in medial-lateral translation, 2.3 mm in anterior-posterior translation, and 0.46 mm in superior-inferior translation for men. The angle-matched difference for women across 100° was 0.58° in varus-valgus rotation, 2.4° internal-external rotation, 0.70 mm medial-lateral translation, 2.1 mm anterior-posterior translation, and 0.78 mm superior-inferior translation. The similar kinematics, while having a greater range of motion, and control of the applied load makes the supine leg press an alternative for quantifying in-vivo knee kinematics.

Intra-articular opening wedge osteotomy for varus ankle arthritis with computer-assisted planning and patient-specific surgical guides: a retrospective case series

Background

Computer-assisted preoperative planning, combined with PSI has become an effective technique for treating complex limb deformities. The purpose of this study was to evaluate the efficacy and safety of the novel technique in corrective osteotomy for intra-articular varus ankle deformities associated with osteoarthritis and ankle instability.

Methods

Nineteen patients with intra-articular varus ankle arthritis were reviewed between April 2017 and June 2019, including ten men and nine women with a mean age of 58.3 ± 9.9 years (range, 38 to 76 years). All patients underwent intra-articular opening wedge osteotomy assisted by 3D virtual planning and PSI. Weight-bearing radiographs were used to assess the radiographic results, including TAS angle, TT angle, TMM angle, TC angle, TLS angle, opening-wedge angle, and wedge height. Functional outcomes were assessed by the AOFAS score, VAS score, and ROM of the ankle.

Results

The average follow-up time was 32.2 ± 9.0 months (range, 22 to 47 months). The average union time was 4.4 ± 0.9 months (range, 3.0 to 6.5 months). The TAS angle significantly changed from 84.1 ± 4.6° preoperatively to 87.7 ± 3.1° at the 1-year follow-up and 86.2 ± 2.6° at the latest follow-up. Similarly, the TT angle, TMM angle and TC angle changed significantly at the 1-year follow-up compared with the preoperative assessment and remained stable until the last follow-up. However, the TLS was not corrected significantly. The postoperative obtained opening-wedge angle, and wedge height showed no significant change with preoperative planning. The overall complication rate was 15.8%. The mean VAS score improved from 5.3 ± 0.6 to 2.7 ± 0.7. The mean AOFAS score improved from 56.2 ± 7.6 to 80.6 ± 4.6. However, the ROM showed no significant change.

Conclusions

Accurate correction and satisfactory functional recovery were attained with computer-assisted planning and PSI in the corrective osteotomy of intra-articular varus ankle deformities.

Supplementary information

The online version contains supplementary material available at 10.1186/s12891-022-05437-z.

In Vivo Syndesmotic Motion After Rigid and Flexible Fixation Using 4-Dimensional Computerized Tomography

INTRODUCTION

Maintaining reduction after syndesmotic injury is crucial to patient function; however, malreduction remains common. Flexible suture button fixation may allow more physiologic motion of the syndesmosis compared with rigid screw fixation. Conventional syndesmotic imaging fails to account for physiologic syndesmotic motion with ankle range of motion (ROM), providing misleading results. Four-dimensional computerized tomography (4DCT) can image joints through a dynamic ROM. Our purpose was to compare syndesmotic motion after rigid and flexible fixation using 4DCT.

METHODS

We analyzed 13 patients with syndesmotic injury who were randomized to receive rigid (n = 7) or flexible (n = 6) fixation. Patients underwent bilateral ankle 4DCT while moving between ankle dorsiflexion and plantar flexion. Measures of syndesmotic position and rotation were extracted from 4DCT to determine syndesmotic motion as a function of ankle ROM.

RESULTS

Uninjured ankles demonstrated significant decreases in syndesmotic width of 1.0 mm with ankle plantar flexion (SD = 0.6 mm, P < 0.01). Initial rigid fixation demonstrated reduced motion compared with uninjured ankles in 4 of 5 measures (P < 0.01) despite all patients in the rigid fixation group having removed, loose, or broken screws by the time of imaging. Rigid fixation led to less motion than flexible fixation in 3 measures (P = 0.02-0.04). There were no observed differences in syndesmotic position or motion between flexible fixation and uninjured ankles.

CONCLUSION

Despite the loss of fixation in all subjects in the rigid fixation group, initial rigid fixation led to significantly reduced syndesmotic motion. Flexible fixation recreated more physiologic motion compared with rigid fixation and may be used to reduce rates of syndesmotic malreduction.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Effects of Weight-Bearing on Tibiofemoral, Patellofemoral, and Patellar Tendon Kinematics in Older Adults

Quantification of natural knee kinematics is essential for the assessment of joint function in the diagnosis of pathologies. Combined measurements of tibiofemoral and patellofemoral joint kinematics are necessary because knee pathologies, such as progression of osteoarthritis and patellar instability, are a frequent concern in both articulations. Combined measurement of tibiofemoral and patellofemoral kinematics also enables calculation of important quantities, specifically patellar tendon angle, which partly determines the loading vector at the tibiofemoral joint and patellar tendon moment arm. The goals of this research were to measure the differences in tibiofemoral and patellofemoral kinematics, patellar tendon angle (PTA), and patellar tendon moment arm (PTMA) that occur during non-weight-bearing and weight-bearing activities in older adults.

METHODS

High-speed stereo radiography was used to measure the kinematics of the tibiofemoral and patellofemoral joints in subjects as they performed seated, non-weight-bearing knee extension and two weight-bearing activities: lunge and chair rise. PTA and PTMA were extracted from the subject's patellofemoral and tibiofemoral kinematics. Kinematics and the root mean square difference (RMSD) between non-weight-bearing and weight-bearing activities were compared across subjects and activities.

RESULTS

Internal rotation increased with weight-bearing (mean RMSD from knee extension was 4.2 ± 2.4° for lunge and 3.6 ± 1.8° for chair rise), and anterior translation was also greater (mean RMSD from knee extension was 2.2 ± 1.2 mm for lunge and 2.3 ± 1.4 mm for chair rise). Patellar tilt and medial-lateral translation changed from non-weight-bearing to weight-bearing. Changes of the patellar tendon from non-weight-bearing to weight-bearing were significant only for PTMA.

CONCLUSIONS

While weight-bearing elicited changes in knee kinematics, in most degrees of freedoms, these differences were exceeded by intersubject differences. These results provide comparative kinematics for the evaluation of knee pathology and treatment in older adults.

Transforaminal lumbar interbody fusion with a silicon nitride cage demonstrates early radiographic fusion

BACKGROUND

Degeneration of the lumbar spine is common in aging adults and reflects a significant morbidity burden in this population. In selected patients that prove unresponsive to non-surgical treatment, posterior lumbar fusion (PLF) surgery, with or without adjunctive transforaminal lumbar interbody fusion (TLIF) can relieve pain and improve function. We describe here the radiographic fusion rates for PLF versus TLIF, using an intervertebral spinal cage made of silicon nitride ceramic (chemical formula Si₃N₄).

METHODS

This retrospective cohort analysis enrolled 99 patients from August 2013 to January 2017; 17 had undergone PLF at 24 levels, while 82 had undergone TLIF at 104 levels. All operations were performed by a single surgeon at one institution. Radiographic and clinical outcomes were compared between PLF and TLIF at 2 and 6 weeks and then at 3, 6, 12, and 24 months.

RESULTS

TLIF patients fused at higher rates compared to PLF at the 3-month (38.5% vs. 8.3%, P=0.006), 6-month (78.7% vs. 35.0%, P<0.001) and 12-month time periods (97.9% vs. 81.3%, P=0.018), with no difference at 24 months (100% vs. 94.4%, P=0.102). Index level segmental motion was significantly less and intervertebral disc height was improved in TLIF over PLF at all follow up intervals. Foraminal height was only greater in early follow up periods (2 weeks, 6 weeks and 3 months). TLIF patients experienced lover rates of PI-LL mismatch which was maintained across long term follow-up. Pelvic tilt was lower following TLIF compared to PLF, with no differences in complication rates between study groups.

CONCLUSIONS

Our retrospective series demonstrated that TLIF performed with silicon nitride interbody cages led to earlier radiographic fusion, greater restoration of disc and foraminal height, increased segmental rigidity and improved sagittal alignment when compared to PLF alone.

Morcellized local grafts as cost effective option for interbody fusion in thoracolumbar fracture dislocation: Seven years follow up of 53 patients

Study design

Retrospective cohort study.

Purpose

Traumatic fracture dislocation of the spine injury is essentially a three column injury that optimally needs surgical intervention to decompress, stabilize and fuse the spinal column. This study evaluate the outcome of posterior and posterolateral decompression, instrumentation and 360° fusion achieved with help of locally harvested autologus morcellized grafts in traumatic fracture dislocation of thoracolumbar spine.

Methods

53 patients were included in this retrospective study. Patients aged 16-55 years, single level fracture dislocation of thoraco-lumbar spine (D5-L5) were included. Patients with multiple level fractures, coexisting degenerative diseases of spine,pathological fractures, patients presenting more than three weeks after initial trauma, patients with concomitant severe head injury that necessitated emergency surgery for the same were excluded from the study. Patients underwent posterior and posterolateral decompression, posterior instrumentation and interbody as well as posterolateral fusion with use of morcellized bone from resected posterior elements. Follow up data at immediate post operative period, 12 months and yearly thereafter up to minimum 7 years was obtained from previous record.

Results

There were 46 males and 7 females. Mean age was 31.15 ± 9.64 yrs. Mean follow up period was 7.4 yrs (range 7-10 yrs). Thoracolumbar dislocation was most frequently noted at thoraco lumbar junction (T10-L2). Thirty six patients had complete neurological deficit (ASIA A) and sixteen had incomplete neurology. At one year follow up, osseous fusion was noted in 48 (90.56%) patients and 5 patients (9.44%) had fibrous union which was determined on CT scan. Immediete post operative, one year and 7 year kyphosis angle was calculated and change in kyphosis angle was not statistically significant. There was no implant failure till last follow up.

Conclusion

Morcellized locally harvested autologus grafts are sufficient to achieve 360° spinal fusion in fracture dislocation of thoracolumbar spine.

Dual energy CT arthrography in shoulder instability: successful iodine removal with virtual non-contrast images and accurate 3D reformats of the glenoid for assessment of bone loss

OBJECTIVE

To evaluate the image quality of dual energy CT (DECT) of the shoulder after arthrography and of virtual non-contrast (VNC) 3D reformats of the glenoid and to compare glenoid measurements on VNC 3D reformats and on 2D CTs.

MATERIALS AND METHODS

DECT arthrography (80 kV/140 kV) was performed in 42 shoulders of 41 patients with instability using diluted iodinated contrast media (80 mg/ml). VNC images and VNC 3D reformats of the glenoid were calculated using image postprocessing. Dose parameters, CT values of intraarticular iodine and muscle, image contrast (iodine/muscle), and image quality (5-point scale: 1 = worst, 5 = best) were evaluated. Two independent readers assessed glenoid morphology and performed glenoid measurements on 2D and 3D images.

RESULTS

Calculation of VNC images and VNC 3D reformats was successful in 42/42 shoulders (100%). The effective dose was mean 1.95 mSv (± 0.9 mSv). CT values of iodine and muscle were mean 1014.6 HU (± 235.8 HU) and 64.5 HU(± 8.6 HU), respectively, and image contrast was mean 950.2 HU (± 235.5 HU). Quality of cross-sectional images, VNC images, and VNC 3D reformats was rated good (median 4 (4-5), 4 (3-4), 4 (3-5), respectively). Detection of an osseous defect was equal on 2D and 3D images (13/42, P > 0.99) with no difference for measurement of the glenoid diameter with mean 28.3 mm (± 2.8 mm) vs. 28.4 mm (± 2.9 mm) (P = 0.5), width of the glenoid defect with 3.2 mm (± 2.1 mm) vs. 3.1 mm (± 2.3 mm) (P = 0.84), surface area with 638.5 mm² (± 127 mm²) vs. 640.8 mm² (± 129.5 mm²) (P = 0.47), and surface area of the defect with 46.6 mm² (± 44.3 mm²) vs. 47.2 mm² (± 48.0 mm²) (P = 0.73), respectively.

CONCLUSION

DECT shoulder arthrography is feasible and allows successful iodine removal with generation of VNC images and accurate VNC 3D reformats of the glenoid for assessment of bone loss.