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Tag Archives: foot and ankle

Evaluating the Ankle Syndesmosis: Injury vs. Instability

Syndesmosis – A Functional Injury

Ankle syndesmosis injury 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
Dr. Daniel Guss, MD, MBA

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.

Clinical Exam

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.

These X-Rays did not show a fracture, but did show subtle calcification in the syndesmoses.
These X-Rays did not show a fracture, but did show subtle calcification in the syndesmoses.

X-Rays taken four months later at Dr. Guss’s clinic showed heterotopic ossification in the syndesmotic region.

Heterotopic ossification was visible in the syndesmotic region in follow-up X-Rays.
Heterotopic ossification was visible in the syndesmotic region in follow-up X-Rays.

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.

A pedCAT weight bearing CT scan revealed the asymmetry under physiologic load.
A pedCAT weight bearing CT scan revealed the asymmetry under physiologic load.

posterio lateral HO

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.

The patient's X-Rays revealed a maisonneueve pattern.
The patient’s X-Rays revealed a maisonneueve pattern.

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.

The weight bearing pedCAT scan revealed a subtle asymmetry.
The weight bearing pedCAT scan revealed a subtle asymmetry.

Subsequently, this patient went on to have surgical fixation performed despite being told originally that he had simply sprained his ankle.

Key Take-Aways

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.

Watch Dr. Guss’ entire lecture here:

Webinar: Applications of WBCT by Dr. Daniel Cuttica, D.O.

CurvebeamANDfootInnovate

Webinar: Wednesday January 16, 2019

9:00 PM EST

CLICK HERE TO REGISTER TODAY!

CutticaEmailBlastGraphicLONG

 

Daniel J. Cuttica, D.O. will share his experience using weight bearing CT in clinical practice in this webinar titled, “Applications of weight bearing CT in common foot & ankle disorders“. Dr. Cuttica is a foot and ankle surgeon practicing at the Orthopaedic Foot & Ankle Center division of the Centers for Advanced Orthopaedics, in Falls Church, Virginia. He is an Assistant Professor of Clinical Orthopaedic Surgery at Georgetown University School of Medicine, and the author of numerous publications in foot and ankle journals.

 

CLICK HERE TO REGISTER TODAY!

 

A FOOTInnovate account is required to register. FOOTInonovate membership is free for foot and ankle specialists.

CurveBeam Plays an Important Role in the Best Research Awards at the EFAS Congress

Dr. Francois Lintz posted about being nominated for best research award at EFAS 2018 and congratulated Dr. Cesar de Cesar Netto for winning the award with his paper on Weight Bearing CT.
Dr. Francois Lintz posted about being nominated for best research award at EFAS 2018 and congratulated Dr. Cesar de Cesar Netto for winning the award with his paper on weight bearing ct.

 

The 12th annual European Foot and Ankle Society (EFAS) Congress was recently held in Geneva. As a part of this prestigious event, Dr. Cesar de Cesar Netto and Dr. Francois Lintz presented papers that were both nominated for research awards. CurveBeam is proud to have played a part in both of these important projects.

Dr. Cesar de Cesar Netto Wins Awards for Research and Best Oral Presentation

 Dr. Cesar de Cesar Netto, Clinical Fellow of Foot and Ankle Surgery at MedStar Union Memorial Hospital, was nominated and won a distinguished research award for his paper titled, “Weightbearing CT and MRI findings of Stage II Flatfoot Deformity: Can We Predict Patients at High-Risk for Foot Collapse?” Earlier in the year, he also won the best oral presentation at the FLAMeCiPP meeting, organized by the Latin American Foot and Ankle Federation.

Dr. de Cesar Netto’s research involved the prediction of soft tissue failure using weight bearing cone beam computed tomography (WBCT), an imaging modality that allows excellent evaluation of the relative three-dimensional positioning of the tarsal bones in dynamic deformities such as Acquired Adult Flatfoot Deformity (AAFD). The study indicated that WBCT can predict ligamentous injuries and dynamic bone deformity in AAFD patients.

Dr. Francois Lintz was Nominated for his Research

 Dr. Francois Lintz an orthopedic Surgeon specializing in Foot & Ankle Surgery in Toulouse, France, was also nominated for a research award for his paper, “3D Biometrics: A Prospective Comparative Evaluation of the Foot Ankle Offset Using Weight Bearing CT Semi Automatic Software.” The objective of Dr. Lintz’s study was to prospectively assess the clinical relevance and reproducibility of the Foot and Ankle Offset (FAO) value for hindfoot alignment, which requires WBCT for measurement, and compare it with previous findings. The study concluded that hindfoot alignment can be measured reliably using WBCT and demonstrated that FAO has good repeatability, and correlates well with clinical examination, 2D findings, and previous literature.

The EFAS Congress  

 The EFAS Congress provides a platform for professionals of all disciplines dealing with foot and ankle surgery and research to share their knowledge and advance the specialty. This year’s program, themed “State of the Art Foot and Ankle Surgery,” included a line-up of internationally renowned surgeons and scientists in the foot and ankle community. For this year’s gathering, the EFAS also invited representatives from two established national foot and ankle societies—the SFAS (Swiss Foot and Ankle Society) and the KFAS (Korean Foot and Ankle Society)—to share their expertise and innovative approaches in foot and ankle pathologies and treatments. The result was a program that provided a multidisciplinary, comprehensive overview of the latest scientific and clinical findings in foot and ankle surgery, state of the art surgical techniques, biomechanics, efficient conservative treatments, and the most recent imaging modalities in the field.

To watch a recording of the Weight Bearing CT International Study Group’s open scientific meeting at EFAS, click here.

Weight Bearing CT Imaging for Cuboid Subluxations

Dr. Michael Chin, DPM, presented how weight bearing CT imaging has changed how he evaluates cuboid subluxations at the American Academy of Podiatric Sports Medicine meeting held near the West Point Military Academy campus in early September, 2015.

Dr. Chin began using the pedCAT in his office in February of this year.

Not much research is out there on how to use plain radiographs to measure cuboid subluxations, Dr. Chin said in his lecture, titled, “Cuboid Syndrome…The Other Side of Heel Pain.”

Dr. Chin has tested using a bilateral oblique projection to understand the cuboid/ metatarsal relationship, and has been able to observe a slide between the head of the fourth metatarsal and the head of the cuboid.

An MRI could be ordered to see the condition of the peroneal tendon, but the study would be limited because the scan would not be weight bearing, he said.. A traditional CT scan would provide great  visualization of the bone, but would provide no information on anatomic alignment.

The pedCAT weight bearing CT imaging system is excellent for evaluating stress fractures, sesamoids, periosteal changes, or anything medullar, Dr. Chin said. Another benefit is he can measure the exact degree of subluxation between the cuboid and the fourth metatarsal head.

Dr. Chin displayed pedCAT images depicting  pre and post-reduction views of a cuboid subluxation.

chin-lecture
pedCAT scan of a pre-surgical patient with cuboid subluxation. Dr. Chin was able to reduce the subluxation to 2.18 mm.

Dr. Chin practices at The Running Institute in Chicago.

pedCAT: Fracture & Fusion Assessments

X-rays of the foot and ankle may not always provide conclusive assessments for post-operative fusions such as of the tarso-metatarsal joint or hind foot joints. Similarly, the physician is often left guessing if a fracture has properly healed.

“The pedCAT takes all the variability out, all the guesswork out of it,” Dr. Martin O’Malley, MD, an Associate Attending Orthopedic Surgeon at the Hospital for Special Surgery in New York, New York, said.

Dr. O’Malley said pedCAT scans allow him to clearly determine if a fusion has healed more than 50 percent, and he decides when to ambulate his patient accordingly.

“I let people walk on it earlier than before, and I keep them off longer than before,” Dr. O’Malley said.

The pedCAT provides a three-dimensional view of fractures that changes the way O’Malley sees this common diagnosis.

“These posterior pieces are often bigger than we thought were based on plain X-ray and they often travel all the way around the medial side as well, which we never thought they did,” Dr. O’Malley said. “You know, we thought it was an infrequent fracture, but now we see it routinely. Now most of my ankle fracture work, I’d say more than half the time, is through a posterior approach. For the first 15 to 18 years of my practice I would do medial/ lateral incisions. Now I’m going to the back of the ankle. And a lot of it is driven by the pedCAT.”

 

pedCAT Stress Fracture Cross Section

 

Above is an example of a navicular stress fracture in a collegiate runner that had not healed at all after six weeks of casting. Were it not for the conclusive pedCAT scan, this patient would have been allowed to ambulate.

Watch Dr. O’Malley talk more about the pedCAT here .

To offer your patients state-of-the-art fracture & fusion assessment, consider a pedCAT for your practice.

 

Welcome to the CurveBeam Blog!

Welcome to the CurveBeam Blog!

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It’s an exciting time at CurveBeam. Almost two years ago  we received FDA-approval for our first product, the pedCAT. The in-office 3D weight bearing imaging system for the foot and ankle has been integrated into orthopedic and podiatric practices around the world.  Foot and ankle specialists, considered leaders in their field, have told us that the pedCAT will become the standard of care for lower extremity imaging in the near future. In fact, in some of their practices, it already is.

We’re dedicated to continuing the improvement of foot & ankle imaging and are excited to share with you the technology advancements, right here on this blog in the upcoming months. So check back often!