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Discussion Looks to Provide Blueprint for Foot and Ankle Deformity Correction

Foot and Ankle Specialist (FAS), a bi-monthly journal for orthopedic surgeons and podiatrists, recently published a roundtable discussion focused on providing insight into the difficult process of deformity correction. For surgeons dealing with the lower extremities, even the central principles of understanding and treating deformities can be extremely complex. Noman Siddiqui, Guido Laporta and John Herzenberg, all of whom carry numerous distinctions in the field of podiatry, all weighed in on the discussion.

Deformity management in cases involving the lower limb can involve high levels of pain. Because of this, while analysis is fairly similar to deformity analysis in other regions of the body, treatment is as much an art as a science. Much of the discussion involves presentation of cases and remarks by the specialists as to how they would care for the patient.

The roundtable ranges from topics on improving education in the field to proper care of patients who are treated with external fixation. Of particular interest is the repeated insistence by the panel that the most essential way to improve the field is to increase the amount of information available to a surgeon before an operation occurs. They remark that, even though patients receive a thorough physical as well as a biomechanical exam, gait analysis, and functional testing, more extensive testing and imaging is needed.

All three of the medical experts point out the need for a computed tomography (CT) scan for the more difficult cases. These scans help to erase any gray areas in the diagnosis and help to evaluate the “mal-union” or “non-union” present in malformed feet and ankles. Dr. Herzenberg even recommended 3D CT technology in order to get a complete picture of the situation, and both a weight and non-weight bearing evaluation.

“[Foot] deformity is complex and may require second-level radiographic studies such as a CT scan,” remarked Herzenberg. “Recently, we have added a standing 3D CT machine in our office, which offers the same advantage from a CT standpoint that we get from plain films taken weight bearing versus non–weight bearing.”

These orthopedic specialists are not alone in their desire for more comprehensive scanning technology when treating deformities. More and more clinics are taking similar steps to those used by Herzenberg’s clinic, The Pediatric Orthopedics Department at Sinai Hospital in Baltimore, which now uses the CurveBeam pedCAT. It is quick, efficient and thorough, and was designed with patients in mind, limiting their discomfort. This is especially important since, as mentioned earlier in the roundtable, pain can be significant when dealing with foot and ankle deformities.

The discussion presents a comprehensive look at the current practices in a complex corner of healthcare, and presents insights into the best way to manage orthopedic deformities in the lower extremities. The specialists involved even go so far as to give advice for those preparing to deal with these cases, and examine current technology that allows them to do so to the best of their ability. To read the roundtable discussion in its entirety, click here.

 

Weightbearing CT Revolutionizing Hindfoot Alignment Measurements

A new study, led by famous Belgian M.D. A. Burssens, emerged in the February issue of Foot and Ankle Surgery. The study examines the use of traditional hindfoot angle measurements versus weight bearing CT and shows how weight bearing CT can help contribute to the pre-operative planning by providing further insights into a physiological hindfoot alignment.

Hindfoot malalignment is a widely-accepted cause of foot and ankle disability and problems. For preoperative planning and clinical follow-up, reliable radiographic assessment of hindfoot alignment is of utmost importance and can affect future health. The long axial radiographic view and the hindfoot alignment view are commonly used for this purpose. The main goal of this study is to obtain measurements from a population with clinical and radiological absence of hindfoot pathology. These values were then compared to hindfoot measurements obtained from the long axial view based on the anatomical axis of the tibia and the calcaneal axis, to point out possible differences attributed to that measurement method.

The study has many key findings related to traditional hindfoot predictive measurements. One major finding questions the commonly held belief that non-symptomatic feet have a slight valgus. When traditional hindfoot angle measurements were applied, the study showed that non-symptomatic feet have a neutral alignment. These results show a more neutral alignment of the hindfoot as opposed to the generally accepted constitutional valgus.

Another major finding was that the weight bearing CT clearly showed the talus. The talus is usually superimposed in plain x-rays and hard to see and can affect the mathematical calculations of the predicted hindfoot angle. So, unlike the Saltzman view, these calculations included the talus.

The ultimate goal of all orthopedic surgeons is to influence the correct alignment of bones. Even the slightest miscalculation in measurement can have lasting consequences on post-surgery recovery and future mobility. As the study notes, “Although surgical hindfoot corrections are frequently performed either extra-articular by osteotomies or intra-articular by arthrodesis, still numerous debate exists on the amount of correction and the ideal foot position after arthrodesis.” This finding could have repercussions on hindfoot position during fusion or in quantifying the correction of a malalignment. Due to the use of weight bearing CT, the inferior calcaneus point can be used during pre-operative planning of a hindfoot correction as an anatomical landmark due to its shown influence on load transfer.

A disadvantage of the study was that it was not truly spatial, as only the coronal plane was used in measurements. In the future, 3D segmentation models will allow for better spatial calculations. Until 3D weight bearing CT is an available option, it is recommended foot & ankle specialists exercise caution when planning from 2D radiographs. This study will contribute to the pre-operative planning by providing further insights into a physiological hindfoot alignment. For more detail, access the article here.

Weight Bearing CT International Study Group Presenters Share Important Findings

The American Academy of Orthopaedic Surgeons (AAOS) held its annual meeting at the San Diego Convention Center from March 14-18, 2017. The Weight Bearing CT International Study Group Meeting on March 18 was an important part of this event. The group promotes dialogue and collaboration on weight bearing CT research initiatives, and is working to create standardized protocols for measurement and analysis.

At the meeting, three presenters shared their findings:

“Using Weight Bearing CT to Understand the Adult Acquired Flatfoot,” Scott Ellis, MD, Hospital for Special Surgery

Dr. Ellis presented three studies that considered the role of weight-bearing CT in Adult Acquired Flatfoot (AAFD). Researchers sought to understand the nature of pain in AAFD, and to determine the cause of and the nature of deformity for AAFD.

The first project assessed the cohort of Stage II patients with lateral hindfoot pain compared to control patients with just medial pain. The study found that subtalar arthrosis was significantly more common in the group with hindfoot pain. Arthrosis is typically undetected on a plain radiograph, but is obvious on a 3D weight-bearing CT scan. The researchers found an important role for weight bearing CT in management of AAFD and in determining the many factors contributing to this condition.

A second study by Bruce Sangeorzan used simulated WB to determine the possible etiology of AAFD. Researchers correlated the angles of the coronal subtalar joint position in patients with AAFD versus a control group. They found that AAFD patients exhibited significantly more valgua in the angle than in the control patients and that the inftal-suptal correlated with a number of measurements related to flatfoot.

A third study at the Hospital for Special Surgery compared peritalar subluxation between AAFD patients and controls using weight-bearing multiplanar imaging. The study found that weight-bearing CT better identified the source of pain in AAFD, and showed where the deformity occurs with respect to talus. According to the study’s results, weight-bearing CT overcomes the limitations of both standard CT and plain radiography.

“Weight-bearing CT of the Foot & Ankle: Literature Review and Indications for Use in the Clinic,” Alexej Barg, MD, University of Utah, Department of Orthopaedics

This study examined different imaging modalities, including conventional radiographs, CT-Arthography, weight-bearing CT, MRI, and ultrasonography. Researchers found that a weight-bearing CT scan offers a tremendous amount of additional information over conventional methods, allows rapid evaluation of complex foot and ankle anatomy with thin-section imaging, improves diagnostic accuracy compared to radiographs, and helps minimize the radiation dose to the patient. An additional benefit is that a cone beam CT scanner is relatively small and requires less capitalization cost than a conventional CT unit.

Dr. Barg also offered a comprehensive literature review of relevant weight-bearing CT studies. He concluded his presentation by sharing cases of weight-bearing CT scanning in clinical use. He found the weight-bearing CT scan is a significant improvement over conventional X-rays, especially in the ability to compare results of different tests and patients through standardized measurements with reliable identifications of anatomic landmarks.

“Rotation of the First Metatarsal in Hallux Valgus Deformity,” Phinit Phisitkul, MD, Department of Orthopaedic Surgery and Rehabilitation, University of Iowa Hospitals and Clinics

Hallux valgus is a complex triplane deformity that may result from intrinsic factors, such as genetics or anatomy, as well as extrinsic factors, such as wearing high heels with a narrow box toe. Previous studies generally did not rely on weight-bearing CT scans. This study reviewed 85 patients who underwent weight-bearing CT using the CurveBeam pedCAT between January 2014 and May 2016.

The study concluded that weight-bearing CT of the foot is helpful in preoperative planning for complex hallux valgus deformities. Researchers also found that pronation of the first metatarsal is more highly correlated with foot structure, for example pes planus, than hallux valgus deformity.

CurveBeam is an innovator setting the standard of care in orthopedic imaging. CurveBeam’s automatic measurement tools lead to better patient outcomes, streamlined practice workflow, and increased revenue. Check out a replay of the 2017 Weight Bearing CT International Study Group Meeting at https://www.youtube.com/watch?v=LHIAF-ExOsY&t=11s .

CurveBeam Is the Innovator in 3D Orthopedic Imaging Technology

Cone beam computed topography, or CBCT, has become the standard of care in orthopedic imaging. This technology has revolutionized the practices of doctors in the orthopedic and podiatric industry. Automatic measurement tools lead to better patient outcomes with the added convenience of point-of-care advanced diagnostics. CurveBeam’s goal is to lead the way with cutting-edge innovations in orthopedic imaging. CurveBeam not only adopts new technology quickly, but is increasingly setting the standard.

CurveBeam imaging products are designed specifically to analyze extremities, especially knees, ankles, and feet. These compact, affordable units give specialists high-quality, weight-bearing 3D views of a patient’s foot and ankle. Scans are low-dose, so units don’t require shielding or dedicated facilities. Units are lightweight, mobile, and require no special power sources, so they can easily become an essential tool in virtually any practice.

In the past, doctors had to interpret images manually. CurveBeam’s software uses artificial intelligence to predict a patient’s future prognosis and recommend a comprehensive treatment plan. Providers will find this advanced capability directly impacts their practice, resulting in improved diagnostics, streamlined workflow, and greater productivity.

CurveBeam is an innovator setting the standard of care in orthopedic imaging. Check out our video below to learn more about this exciting technology!