The WBCT Society presented another Open Scientific Meeting on September 13, 2019 at the AOFAS Conference in Chicago. Watch the highlight reel from the meeting above to see some of the key moments or read the summary below!
The WBCT Society is an independent research organization. CurveBeam is a proud sponsor of the Society.
New Leadership:The WBCT Society presented Dr. Martinus Richter, MD, PhD, a plaque for serving as founding president. Dr. Richter’s term ended at the meeting, and incoming president Dr. Alexej Barg, MD, assumed the role.
New Research Protocols: Dr. Alexandre Godoy, MD, demonstrated how the University of Sao Paulo in Brazil has designed three new research protocols for its CurveBeam LineUP weight bearing CT system. These include:
Cavus varus deformity: perform a Coleman block test clinically and during weight bearing CT to determine if the Coleman block test changes alignment measurements.
Hallux valgus deformity: use weight bearing CT to assess 1st TMT gapping, collapse of medium column, and 1st MT and sesamoid rotation.
Congenital club foot: Investigate residual club foot using WBCT to try to understand relationships between tarsal bones involved in the deformity.
The optimal workflow for in-office Weight Bearing CT (WBCT) imaging is to get insurance authorization, perform the scan, and review scan results all during the initial patient appointment.
Hallux valgus is a tri-plane deformity, and weight bearing allows for a better understanding of coronal plane rotation.
Post-operatively, weight bearing CT can provide a precise view of the rate of fusion healing.
The webcast covered the importance of weight bearing in foot and ankle imaging, the applications of weight bearing CT in common foot and ankle disorders, and how it can be incorporated effortlessly into practices.
According to Dr. Cuttica, “Weight bearing is the functional position of the foot. It allows for us to better determine alignment, to form an assessment of the foot, and to formulate treatment plans. So, weightbearing, obviously as we all know, is very, very important.”
A surgeon at Orthopaedic Foot & Ankle Center (OFAC) in Falls Church, Virginia, Dr. Daniel J. Cuttica, DO, boasts a number of specialties and interests, including foot and ankle surgery, reconstructive surgery, sports-related foot and ankle disorders, cartilage disorders, total ankle replacement, diabetic limb salvage, and dance medicine.
Dr. Cuttica states, “When you evaluate a patient, in addition to clinical exam, you know that imaging is going to be very valuable in diagnosing, treating, and assessing outcomes in foot and ankle.”
However, with weight bearing imaging, you can more reliably identify pathology such as subtle arch collapse, loss of cartilage/joint space, degenerative changes, and impingement.
The Limitations of Conventional CT vs. the Benefits of WBCT
When compared to plain X-Rays, “Computed Tomography (CT) can be very, very beneficial for bone and joint problems, and it does give us a large amount of additional information.” However, Dr. Cuttica explains, “The biggest limitation, at least in foot and ankle, with CT again, is probably your inability to obtain weight bearing images.”
The benefits of CBCTs include:
Easy to operate
Shorter scan time
Optimal patient positioning
Flexible siting/easy relocation
There are also many advantages to using WBCT, including:
Ability to obtain weight bearing images
High contrast and spatial resolution
Fast image acquisition time
Decreased radiation (typically 0.01-0.03 mSv vs. 0.07 mSv for Conventional CT)
Relatively small scanner size with portability
Less capitalization cost than Conventional CT
Implementing In-Office WBCT for Foot & Ankle
According to Dr. Cuttica, because of its low radiation dosage and small size, CBCT is ideal for an office setting. For patients, a WBCT scanner in the office is more convenient, can help to avoid unnecessary follow up appointments, and allows for immediate feedback of their diagnosis. For physicians, an in-office WBCT is also more convenient, enabling quicker treatment plan formulation, helping to avoid overbooking, while allowing for more rapid surgery scheduling.
Dr. Cuttica reviewed three office workflow options for in-office WBCT imaging:
Option A – Scan and have patient follow up to go over scans at a later date (not the most efficient)
Option B – Get insurance authorization and perform the scan at the next visit before the patient is seen
Option C – Get insurance authorization, perform the scan, and go over scans at initial appointment (most efficient and most convenient for patients)
Further, WBCT images can be conveniently emailed or uploaded to another doctor or radiologist.
Dr. Cuttica said the most common and beneficial WBCT foot and ankle applications include:
Midfoot/Lis Franc injury
In Hallux Valgus, WBCT Scans Accentuate Deformities & Guide Treatment
(17:03) In hallux valgus—a triplane deformity—it’s necessary to understand all the components of the malformation. Dr. Cuttica pointed out that WBCT allows for better understanding of coronal plane rotation. As you can see in the image below (17:40), the WBCT imaging clearly shows the first metatarsal joint architecture, the sesamoid position, if there is any flattening/erosion of the crista, as well as a first metatarsal rotation, all of which need to be taken into account when treating bunion deformity.
(18:16) Dr. Cuttica displayed a typical case of a 47-year-old female with bunion pain who, upon both exam and radiographically, had a hypermobile first ray with some inter-gapping at her first tarsal-metatarsal joint, as well as a moderately sized bunion. (19:43) When Dr. Cuttica performed a WBCT, the rotation of her first metatarsal was visible. Due to the patient’s instability and hypermobility at the joint, Cuttica’s team treated her with the Lapidus procedure—correcting her IM angle and coronal frontal plane rotation—as well as an Akin osteotomy.
(19:55) At the 6-week post-op exam, the patient’s foot looked fairly healed, and allowed the patient to progress with some activity. (20:19) At the 12-week exam, however, an additional WBCT allowed Dr. Cuttica to better assess the sesamoid position and evaluate the fusion. The sesamoids looked reduced, but it was also revealed that the patient was not fully fused.
These comprehensive views enabled Dr. Cuttica to better progress with the patient’s treatment—in this case, limiting the patient’s activities as she had a bit more healing to go.
Many have long thought that the means of assessing osteoarthritis in the knee are less than ideal.
Although conventional X-ray radiographs are widely considered as gold standard for the assesssment of knee OA, in clinical and scientific settings they increasingly bare significant limitations in situations where high resolution and detailed assessment of cartilage is demanded. – Wick et al, Gereontology. 2014; 60(5).
Current standard of care consists of a series of X-rays on a routine interval basis to assess whether disease is progressing further and corresponding with the patient’s symptoms. There is questionable reliability of joint space width (JSW) measurements from X-ray, and it is difficult to decipher whether there has been a significant change in anatomy to explain the patient’s worsening symptoms.
Watch the video to see a bilateral weight bearing CT dataset of a patient with osteoarthritis in his knees.
CurveBeam’s cone beam CT technology offers high resolution, axial, coronal, and sagittal views in 0.3mm slices generated from a 30 second scan. This provides 3-dimensional, weight bearing information with radiation exposure levels almost equivalent to the standard series of knee X-rays. The 30 second scan is much faster for the technician to acquire compared to the back and forth for multiple views in an X-ray series.
Incorporating weight bearing CT technology into daily practice could facilitate complete visualization of the joint surface in axial slices and take into consideration the effects of weight bearing at the joint line. In time, clinicians should be able to provide more detailed information on location and progression of disease for their patients, and therefore, determine the best course of care moving forward.
In this episode of the CurveBeam podcast, host Vinti Singh sat down with Dr. Martinus Richter, MD, Ph.D.to discuss the results of his latest published study: “Results of more than 11,000 scans with weight-bearing CT – Impact on costs, radiation exposure and procedure time.” This first-of-its-kind study examined the economic implications of CT scans versus radiographs for patients.
Click here to download the execuctive summary for this episode of CurveBeam Connect, featuring Dr. Martinus Richter, MD, PhD.
Dr. Richter is department head of the foot and ankle orthopedic surgery section at Hospital Rummelsberg in Rummelsberg, Germany and has published numerous studies in orthopedic journals.
Dr. Richter oversaw a study, which was conducted over more than five years. to assess the benefits of using weight bearing CT (WBCT) instead of a combination of weight bearing radiographs (R) and conventional CT (CT). The study looked at the modalities’ impacts on costs, radiation exposure and procedure time.
In the study, 11,009 scans, taken from July 2013 through March of 2019, were obtained from 4987 patients—45% (4,897) before treatment; 55% (6,022) at follow-up—with a yearly average of 1,957 WBCTs (bilateral scans). These were compared to 1,850 Rs (bilateral feet, dorsoplantar and lateral, metatarsal head skyline view) and 254 CTs obtained from 885 patients (RCT group) in 2012.
The conclusions help to solidify that not only can WBCT more precisely measure bone position than conventional R and CT scans, but also decreases the time needed for image acquisition by 77% and radiation dosage by 10%, while increasing institution financial profitability by $57.19 (51€) per patient.
CT assessment of patients casted for a non-displaced scaphoid fracture shows union occurring at approximately 7.5 weeks, with a majority of fractures healing in less than 6 weeks, according to a 2016 study by Ruby Grewal et al. Similar studies using plain X-Ray demonstrated union time to be anywhere between 10 – 24 weeks. The authors noted the union time on CT may even be overestimated because the majority of patients’ first CT scan after casting was not until 6 weeks.
In a previous study, Professor Timothy Davis wrote CT studies demonstrate healing of a non-displaced fracture treated with a plaster cast can occur in as little as 4 weeks. If a fracture is displaced less than 2 mm, Davis said those CT studies suggest a plaster cast for 8 – 12 weeks.
CT is ideally performed for all scaphoid waist fractures in the first week after injury to classify whether they are displaced or non-displaced, said Professor Davis, an orthopedic surgeon at Woodthorpe Hospital in Nottingham, UK said in his research paper.
By using CT as a baseline, researchers at the Roth/McFarlane Hand and Upper Limb Center in London said they were able to identify fractures which may have appeared non-displaced on X-Ray, but were actually minimally displaced.
“We feel that the added visualization of CT over plain radiography enables the surgeon to properly select which fractures are appropriate for non-operative cast treatment with an expected high degree of union,” the researchers said in a study published in The Open Orthopaedics Journal.
Out of the research setting, routine CT scans of scaphoid fractures may not be practically feasible, Professor Davis wrote.
“I appreciate that [routine CT assessment of scaphoid fractures] is impossible in many centers at the present time but it should become increasingly possible in the future,” Professor Davis wrote in the medical journal “Annals of the Royal College of Surgeons of England” in 2013.
The InReach is a compact CT imaging system dedicated to the hand, wrist and elbow. The system received FDA and CE approval in 2017. Since then, it has been installed in leading orthopedic centers and hospitals in the United States. The InReach allows orthopedic practices to offer CT imaging at the point-of-care.
“InReach has been an excellent asset allowing in-office imaging and rapid CT evaluation of the hands with complex diagnostic dilemmas,” said Dr. Lloyd Champagne, an orthopedic surgeon at the Arizona Center for Hand to Shoulder Surgery in Phoenix.
Fifteen percent of acute fractures of the scaphoid waist fail to unite if treated non-operatively in plaster, resulting in a persistent loss of function, according to the 2013 article. Plain X-Rays do not clearly show fracture features such as displacement and communition. Previous inter-observer studies have shown radiographs of scaphoid fractures are neither sensitive nor specific.
For professional athletes, injuries mean reduced playing time, impacted performance, and, in rare cases, an end to their careers. These injuries often affect the lower extremities, primarily because their sports require high-risk activities like jumping, cutting movements, and collision with other players. While traditional scanning techniques have mainly been used to identify injuries, a recent study found that weight-bearing cone beam computed tomography (CBCT) may be crucial to not only identify anatomic risks but also to help develop treatments explicitly tailored to the needs of professional athletes.
Incorporating new tech
In The Orthopaedic Journal of Sports Medicine, Dr. Cesar de Cesar Netto, et al. examined the morphology of foot injuries in 45 active NBA players. The doctors used weight-bearing CBCT scans to obtain 3D imaging of each foot. These scans provide more accurate alignment measurements than traditional scans and offer views of the foot while the player’s natural weight is being placed on it.
The study sought to discern whether the morphology of NBA players differed from that of the population at large, and whether the morphology changed based on position played. Foot and ankle injuries account for 27 percent of professional sports injuries, and 85 percent of basketball players experience at least one ankle sprain in their career.
Getting a better look
The players who participated in the study ranged from 20 to 31 years of age, and in total 29 right feet and 25 left feet were studied. All images were taken using a state-of-the-art pedCAT CurveBeam pedCAT system to obtain reliable and accurate images of each subject, and measurements were taken both manually and using the automatic TALAS measurement tool included with CurveBeam’s CubeVue software. TALAS is a research tool and is not available for clinical use. This is significant as it is the first time that a study of the foot morphotypes of NBA players has been conducted.
The study found that, for the most part, NBA players have standard alignment in their lower extremities, although they do tend to have high arches and varus hindfoot alignment. These trends were slight, but they are related to foot injuries and should still be noted. Building up a database of weight-bearing CBCT scans of professional athletes could also allow specialists to have a new control group to compare scans to, which would be enormously beneficial., the study authors said.
Better analysis means better results
Incorporating weight-bearing CBCT scans like those of CurveBeam’s pedCAT can save players, and the league as a whole, both time and money in the long term. Not only will they be able to watch for warning signs, but they will have a complete view of available injuries and will could develop more specific training regimens geared towards returning athletes to the court as quickly as possible.
You can read the full study by Dr. de Cesar Netto, et al. here.
Some degree of subtalar joint subluxation, as well as sinus tarsi impingement, was found in approximately 70 percent of patients with flexible adult acquired flat foot (AAFD) in a recent imaging study using MRI and weight bearing CT (WBCT) imaging.
Investigators used the imaging to assess which soft tissue structures demonstrating MRI signs of degeneration would correlate and influence more positive findings of bone collapse.
The study results were on display in the poster section of the AAOS Annual Meeting and summarized by the AAOS Daily News.
Investiagators obtained MRI and WBCT imaging for 55 patients. Patients were evaluated for markers of arch collapse including increased valgus alignment of the hindfoot and forefoot abduction. Subfibular impingement was found in only 9 percent of patients.
“The significant and isolated influence of pronounced degeneration of the ligaments as positive indicators of more severe collapse of the bony architecture in AAFD patients, represented by subtalar joint subluxation and subfibular impingement, must be considered essential findings,” Dr. Cesar de Cesar Netto, a coauthor of the study, told AAOS News Daily. “Since we don’t really know which structures degenerate first in AAFD, our results point toward an increased importance of the ligamentous structures in the development and progression of the pathology, with the degeneration of the PTT potentially representing a late finding and only the tip of the ice berg.
The CurveBeam pedCAT is the only weight bearing CT imaging system with a field of view large enough to capture a bilateral foot and ankle scan. Flat foot degeneration is often a bilateral condition.
Ankle syndesmosis injury, commonly known as high ankle sprain, is one of the most common cases seen by foot and ankle specialists. An estimated 11% of all ankle injuries and 8.5-18% of all ankle fractures have injury to the syndesmosis. An inaccurate diagnosis can lead to chronic problems or repeat surgeries. Common indications for delayed surgery or reoperation include improper diagnosis, malreduction and inadequate fixation.
The syndesmosis connects the tibia and fibula above the ankle joint. One of the most difficult distinctions to make is whether the injury is isolated to the syndesmosis itself or if it has affected the stability of the ankle joint as well.
Dr. Daniel Guss, MD, MBA, assistant professor of orthopedic surgery at Harvard Medical School, took a deeper look at syndesmosis and how weight bearing CT imaging could improve diagnostic ability in a presentation he delivered to the WBCT International Study Group in July 2018.
Syndesmosis – Variabilities Are Common
The ankle syndesmosis serves two main functional purposes. First, it is designed to maintain the spatial relationship between the tibia and fibula in order to stabilize the ankle mortise throughout weight bearing activity. Second, it allows for flexibility of the ankle mortise in the coronal plane along the talar dome throughout various degrees and dorsiflexion and plantarflexion.
Dr. Guss reminded clinicians that when assessing the functional ability of the syndesmosis, it is important to note that recent studies have shown considerable variability in the concavity of the incisura, bony overlap, and clear space within the ankle mortise from one patient to another. In this regard, comparative anatomy images of the left and right ankle are essential for a thorough evaluation.
During a physical exam, the most common tests for evaluation of syndesmosis injury are external rotation stress test, calf squeeze test, and cross-legged test. By and large, all of these tests give greater indication of injury, but all have low sensitivity and specificity, Dr. Guss said. In addition, a positive test from any of these maneuvers is not considered diagnostic.
Imaging – Need for Contralateral Evaluation
Once history and physical exam have been completed, most clinicians turn to initial standard radiographs for evaluation. Tibia/fibula overlap, tibia/fibular clear space, and medial clear space are most often the areas of focus for more definitive diagnostic information in regard to instability. Most will attempt dynamic stress radiographs with high level of clinical suspicion.
However, Dr. Daniel Guss explained the importance of contralateral evaluation, as there has been great variability in measurements of the syndesmosis using weight bearing CT imaging within the same joint when measured in neutral, maximum external rotation, and maximum internal rotation. There is also evidence of significant syndesmosis measurement difference in weight bearing versus non-weight bearing images of uninjured ankles. This further illustrates the flexibility of the syndesmosis as a support structure.
Finally, if MRI is believed to be necessary, it is important to remember that this modality is very successful at detecting injury, but it does not shed any light on instability as it is a non-weight bearing image, Dr. Guss said.
Case Study – Undetected on X-Ray
Dr. Guss shared a case in which a 20-year-old male fell down a flight of stairs and thought he had sprained his ankle. He went to his college health services and obtained an X-Ray, which was negative for fracture. However, the X-Ray did show subtle calcifications within the syndesmoses.
X-Rays taken four months later at Dr. Guss’s clinic showed heterotopic ossification in the syndesmotic region.
Dr. Guss ordered a pedCAT weight bearing CT so he could assess the HO further. He was able to see the asymmetry under physiologic load at the distal tibio-fibular articulation and also that the HO was forming posterio-laterally.
The patient ultimately underwent an excision of the HO and fixation.
Case Study – Subtle Asymmetry
Dr. Guss shared another case where a Gentleman in his 50’s presented to the ER complaining of right ankle and lower leg pain after slipping on ice. Traditional x-rays were obtained, and he was diagnosed with a Maisonneuve-type injury with proximal fibula fracture and medial ankle sprain.
Upon follow up, the patient had a weight bearing CT scan done of both ankles that allowed for cross-section comparison under physiologic stress. This scan revealed subtle asymmetry and widening between the distal tibia and fibula of the injured right ankle compared to the non-injured left ankle.
Subsequently, this patient went on to have surgical fixation performed despite being told originally that he had simply sprained his ankle.
In conclusion, syndesmosis injury can be easily missed and yet carries long term implications for functional instability and chronic pain. When considering what imaging studies are necessary, it is essential to look at weight bearing and contralateral images to obtain a thorough picture of functional anatomy specific to that patient. As weight bearing CT technology becomes more widely available, this may be the most streamlined way to evaluate bilateral, weight bearing images to diagnose ankle syndesmosis instability.
Gaining an accurate and complete measurement of the hindfoot alignment of a patient with adult acquired flatfoot deformity (AAFD) is difficult when using traditional clinical assessment. In a paper published in the journal Foot and Ankle Surgery, Dr. Cesar de Cesar Netto, MD, PhD, and his colleagues posit that weight-bearing cone beam computed tomography (CBCT) scanning technology may give a more complete, three-dimensional view of the deformity and its underlying causes.
In the article, “Hindfoot Alignment of Adult Acquired Flatfoot Deformity,” the team studied twenty patients with AAFD, twelve men and eight women. All participants had to undergo a clinical assessment of their hindfoot alignment and got a weight-bearing CBCT scan. After all tests were completed, the team found that the weight-bearing CBCT scans provided far more accurate, reliable and repeatable measurements than those of the clinical assessments, thus making a strong case for the use of cone beam technology in AAFD diagnosis and treatment.
In the video below, Dr. de Cesar Netto describes how WBCT assists in AAFD evaluation. “We have been finding really interesting things while studying the flat foot deformities in the weight bearing CT images, most of them related to coronal plane assessment. But it’s not just that,” Dr. Cesar de Netto says. “We are trying to use the three dimensional environment to find out how the deformity progresses.”
The problem with current practices, according to de Cesar Netto and his colleagues, is that they rely on two systems that make it difficult to obtain universally accepted results. The first is radiographic examinations. These are two-dimensional and cumbersome, with further difficulty added when trying to discern hindfoot alignment due to the complexity of the subtalar joint. Not only that, but these examinations are especially prone to improper positioning which would throw off the results. The other traditional system used for hindfoot alignment measurement is made up of a series of clinical measurements including simple visual evaluation. These measurements have consistently been shown to be inaccurate and highly variable from physician to physician.
Recent advancements in CBCT technology now allow physicians to obtain a three-dimensional, highly detailed view of a patient’s lower extremities. They also allow for a complete picture of both the soft-tissue and bone within the foot, so that no issues go overlooked. Of particular interest to the study at hand was the fact that CBCT allows for scans to be taken of the foot in a natural, weight-bearing state. As AFFD is highly dynamic, analysis of the condition with the effects of a patient’s full body weight can be immensely beneficial when developing a treatment plan.
Leading the way with weight-bearing cone beam technology is CurveBeam. The CurveBeam LineUP is revolutionizing how physicians approach diagnosis and treatment plan development as their technology provides complete views of the lower extremities with high image quality.
A study published in the International Journal of Biomedicine concludes Cone Beam CT (CBCT) imaging is the “method of choice” for compound anatomical structures, such as the wrist, and post-traumatic changes in bone tissue.
“Considering the low dose radiation and high image quality,” CBCT could be used as a priority method of choice to assess the structure of wrist and hand bones and be done as a first step in diagnostics, replacing standard radiography,” according to the study, which was led by A. Yu Vasiliev PhD, MD, at Moscow State University of Medicine and Dentistry.
The wrist and hand are one of the regions in the human body most prone to injury and disease. Only one-fifth of incapacitation is the direct result of injury or disease. Many cases of incapacitation are instead due to mistakes made in diagnosis and treatment, according the study. Vasiliev and his team examined the capabilities of cone-beam computed tomography (CBCT) in the assessment of the structure of wrist and hand bones.
The study appeared in a 2013 issue of the International Journal of Biomedicine.
Vasiliev obtained a Cone-beam CT scan of the wrist and hand of a group of voluntary patients, which included 40 members aged 22 – 68 years. A Magnetic resonance imaging (МRI) exam was also performed on 80 percent of the volunteers, multi-slice CT scan was performed on 40 percent of the volunteers, and digital microfocus radiography and standard radiography exams were performed on 63 percent of the volunteers.
When all 40 CBCT scans were examined, structural changes of wrist and hand bones were detected in 77.5 percent of cases, and consolidated fractures and false joints of bones were detected in 10 percent of cases. All the changes were also detected by the multi-slice CT images and digital microfocus X-Rays, but were not defined on standard X-Rays.
The results demonstrated that CBCT provides high efficiency in detection of form, measurements and structural changes of bones of the anatomic region. The cone beam CT images of wrists and hands provided high-resolution, detailed mapping of bone structure, as well as accurate differentiation of bone trabeculae and minor structural changes and defects.
A new generation of cone-beam scanners makes it possible to obtain high-quality images without exposing the patient to a high dose of radiation. This facilitates more and better examinations in orthopedics and traumatology for better patient outcomes.
CurveBeam designs and manufactures Cone Beam CT imaging equipment for the orthopedic and podiatric specialties. To access the full study, please click here.