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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.

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.

AOFAS Annual Meeting – CurveBeam Symposium Recap

Weight bearing CT is a vital tool for determining the cause of inexplicable pain, and also for avoiding painful surgical complications.

That was the takeaway message from a talk by Dr. Phinit Phisitkul, a clinical associate professor of orthopaedics at the University of Iowa. He shared some of his most interesting cases at a CurveBeam sponsored symposium held during the AOFAS Annual Meeting in Long Beach during the evening session.

We’ve selected three of his cases to share on this blog:

18-year-old male with Noonan Syndrome & severe flat foot: The patient presented with an unusual amount of pain that was difficult to diagnose on plain X-Ray. A weight bearing CT scan revealed he had a severe deformity – a congenital vertical talus. He also had severe impingement.

Vertical Talus - Weight Bearing CT
Vertical Talus – Weight Bearing CT
Impingement - weight bearing CT
Impingement – weight bearing CT

58 year-old male with ankle arthritis: The patient presented with a lot of pain in the ankle joint. A weight bearing CT scan showed a subluxation of the ankle joint and dramatic impingement of the calcaneal fibula. Interestingly, the subtalar joint was in pristine condition. Dr. Phisitkul determined the patient was a good candidate for ankle replacement and hindfoot realignment, and that his subtalar joint could be spared.

Calcaneal-fibular impingement and arthritis - Weight Bearing CT
Calcaneal-fibular impingement and arthritis – Weight Bearing CT

41-year-old female with Hallux Valgus: A weight bearing CT scan revealed a bone spur on the patient’s first metatarsal head. If the doctor had done a normal release, the spur may have ended up pinching the sesamoid. Instead, he performed a lateral release and excised the bone spur.

1st MT Bone Spur - Weight Bearing CT
1st MT Bone Spur – Weight Bearing CT





pedCAT: A Positive User Experience


Baravarian Western

“After using the pedCAT for a year, I am very impressed with how much I need it, and how many different things I use it for,” Dr. Bob Baravarian said at the 2015 Western Foot and Ankle Conference held in Anaheim, Cali. The California Podiatric Medical Association hosted the meeting at the end of June.

Dr. Baravarian cited Hallux Rigidus as one example where pedCAT imaging has been helpful because he is able to properly assess the sesamoids.

Dr. Baravarian confirmed his practice is realizing positive revenue streams as a result of the device.

Diagnostic Options for Freiberg’s Avascular Necrosis

The underlying causes of avascular necrosis of the second metatarsal head are not totally understood, but early diagnosis is essential. Delayed treatment can result in a collapse of the articular surface, making treatment more difficult.

Dr. Bob Baravarian, DPM, explained his preferred methods for diagnosing the condition in the May 2015 issue of Podiatry Today.

An X-Ray will show the overall contour and alignment of the metatarsal head.

MRI is one option for a secondary study, but edema and swelling can limit visualization of the surrounding bone region, Dr. Baravarian explained.

Weight bearing CT scans, meanwhile, clearly show the bones and joints and how they are aligned. Weight bearing CT is “our go-to imaging study,” Dr. Baravarian said in the article.

Source: Podiatry Today
Source: Podiatry Today
Source: Podiatry Today
Source: Podiatry Today

“With adequate diagnostic testing and proper patient and procedure selection, one can treat avascular necrosis of the metatarsal head with good to excellent outcomes,” Dr. Baravarian said.

Dr. Baravarian is the director of University Foot and Ankle Institute in Los Angeles. His practice offers weight bearing CT imaging services.

Weight Bearing CT in Everyday Practice

“In my opinion, weight bearing CT will be the standard of care in the next couple of years,” Dr. Alex Tievsky, DPM, said in a lecture at the Graham International Implant Institute 8th Annual Symposium in Miami, on April 17. “This is really the future of not just foot and ankle, but the future of medicine.”

“2D is beginning to be phased out,” Tievsky said. “Now we’re beginning to see the problem from all angles and all planes, so this is super helpful from that respect.”

Dr. Tievsky presented a number of cases where he benefited from access to weight bearing 3D technology in his office.

Clinical Case #1

A 50-year-old female presented with bilateral flat feet for 20 years. She had heard about the HyProCure procedure, which corrects hindfoot misalignment through a minimally invasive procedure. She was eager to have the procedure done, no matter the cost. Dr. Tievsky took a pedCAT scan, and found she had a severe talar coalition.

talar calc coalition coronal left

“How many times do you catch a coalition on an X-Ray? It’s hard,” Dr. Tievsky said. “Sometimes you can see a halo sign, but it’s often missed. On the first visit, I was able to tell her, we either have to resect this coalition or we have to do a fusion. It’s impossible to get this level of information on an X-Ray.”

Clinical Case #2

A 16-year old girl came in with first metatarsal head pain. She had already been to two other podiatrists in the last six months, and they had prescribed steroid injections.

The pedCAT revealed a fracture on her fibular sesamoid that is extremely easy to miss on X-Ray.

fractured sesamoid

“Within her first 10 minutes in the office, we had a diagnosis,” Dr. Tievsky said. “We treated her appropriately. We immobilized her for eight weeks and gave her a bone stimulator. And she was pain free, three podiatrists later. She was happy, her mom was happy, and she never came back.”

Clinical Case #3

A patient presented with a lateral plantar fasciitis, a talo-tarsal dislocation, back pain for five years, knee pain, and hip pain.

A pedCAT revealed she had a tumor in her bone and it was eroding it. “There was no way we would have caught it on X-Ray,” Dr. Tievsky said. “We sent her out for oncology. It could have a malignant tumor, and we could have saved her life.”

Cyst Coronal

The scan is quick to take and you have a full work-up in about three minutes, Dr. Tievsky said as a closing statement. “This is a super important tool,” he said. “I’m kind of biased. I love this now. I can’t practice without it.”

Weight Bearing CT Scans for the Evaluation of Implant Arthroplasty Candidates

Weight bearing CT scans can be critical to a proper diagnosis, even for routine procedures.

In the following case, for example, a patient’s X-Rays indicated that he would be a good candidate for a metatarsal head hemi-implant arthroplasty. However, when the patient sought a second opinion, a weight bearing CT (pedCAT) scan revealed the true condition of the metatarsal head, and the surgical plan was considerably altered as a result.

A 60 year-old male presented complaining of a many year history of 2nd metatarsophalangeal joint pain, especially joint stiffness and pain. His pain increased with attempted 2nd MTPJ dorsiflexion.  In gait, he felt pain when rolling onto the ball of the foot.  His first surgical opinion recommended a metatarsal head hemi-implant arthroplasty .

Due to the excessive bony superimposition on the patient’s lateral X-Ray, it is difficult to accurately assess the shape of the 2nd metatarsal head.  A bone fragment can be visualized over the dorsum of the first or second metatarsal heads.  The AP weight bearing images demonstrate 2nd metatarsophalangeal  joint space narrowing.

Implant Arthroplasty Candidate X-Ray X-Ray 2

The patient sought a second opinion from a podiatric surgeon who offers in-office weight bearing CT services. The podiatrist performed a pedCAT scan and found the 2nd metatarsal head had sustained an old fracture. The pedCAT scan revealed that the dorsal 50% of the 2nd metatarsal head had been avulsed dorsally and a portion of the metatarsal head presented as a dorsal loose body.  The 2nd metatarsal head didn’t have the bone stock or bone volume to support a hemi-implant. The second opinion recommended recontouring the metatarsal head and performing an interpositional arthroplasty. The patient chose to have the second surgeon perform his surgery.

fractured 2nd MT head pedCAT weight bearing CT

A CT scan is not typically ordered to evaluate feet preoperatively.

“We are all trained to believe our eyes and to believe the information present in X-Ray images.  In this case it is assumed that the 2nd metatarsal head has a normal contour, length and bone volume.  The X-Rays demonstrate joint space loss and justify the hemi-implant arthroplasty, but adequate bone volume is required for implant stability and fixation. You just assume it’s going to be OK,” said Dr. Kent Feldman, DPM. “And if you do that as a routine, you’re going to get caught over and over and over in the operating room making mistakes or making assumptions that aren’t necessarily true.”

Dr. Feldman integrated a pedCAT into his surgical practice in 2012.

Dr. Gary Briskin: The pedCAT is the Future

“It’s the future – embrace it. It’s your future – control it.”

Dr. Briskin lectures on weight bearing CT imaging for foot 7 ankle
Dr. Briskin lectures on weight bearing CT imaging for foot 7 ankle

Dr. Gary Briskin delivered this motivating message at the Foot & Ankle Business Innovations conference in Chicago on Jan. 23.

Dr. Briskin, of University Foot & Ankle Institute in Santa Monica, Cali,  discussed how the pedCAT weight bearing CT system has improved his practice since his group acquired one last year.

His main take-away points were:

– The pedCAT gives you the advantage when it comes to diagnosing pathology.

“You can solve that Lisfranc case no one else can,” Dr. Briskin said. “It opens up the midfoot, which historically has been a problem for us.”

– The pedCAT allows him to clearly determine if bones and joints are completely fused after surgery.

“I do a lot of lapidus procedures,” Dr. Briskin said. “My concern; is this patient fused adequately to start bearing weight?” The exact level of fusion is visible with a pedCAT scan 5 – 6 weeks later, and with minimal scatter.

– Radiologists like the pedCAT images

“I think I’m getting a better CT, because it’s weight bearing and I think the quality is far superior. We get all of our CTs read by a radiologist. We have everything sent digitally. And the feedback we get is they are also impressed with the quality of the images.”

pedCAT: Optimal Visualization of Metal Implants and Hardware

hardware in midfoot1 charcot hardware


One advantage of CT imaging over MRI imaging is the ability to scan patients with metal implants. However, the CT scans may still suffer from severe artifacts that usually show up as streaks or dark, obscured areas. Although artifact reduction technologies continue to improve image quality, metal implants can still pose a major challenge to diagnosis.

Radiologists and foot and ankle specialists are routinely impressed with the pedCAT’s ability to visualize complex post-surgical cases. To schedule an in-office demo to view these cases in more detail, contact your CurveBeam sales representative today.

The pedCAT cone beam CT imaging system for the foot and ankle provides high resolution, high quality imaging, even with metal implants and hardware.


pedCAT: Visualizing the Sesamoids in a Hallux Valgus Deformity

rotated sesamoids

Dr. Robert Weinstein, DPM,  recently lectured at The International Foot & Ankle Foundation for Education and Research meeting in Maui, Hawaii, and presented an illuminating finding from his clinical practice: the pedCAT can be a useful diagnostic tool for a very common foot condition.

When it comes to Hallux Valgus, or bunions, a 3D scan could make a major difference in the surgical plan.

Valgus, by definition is a three-dimensional problem, since there is a rotational component, Dr. Weinstein explained.

And “sesamoids, in my mind, drive the whole deformity,” Dr. Weinstein said. “You have to be able to look at them very carefully.”

However, the standard positioning for the “sesamoid view” on plain X-Ray places the patient in an abnormal position, and therefore is not clinically relevant, he added.

“Sesamoid condition is just as important as sesamoid position,” Dr. Weinstein said. “If I see sesamoids that are diseased, it doesn’t matter how good I am at reconstructing those MPJs, that I can get that metatarsal back to zero or two degrees, it’s going to be a failure. So it’s very important to look at the crista and the condition of each of those sesamoids.”

Dr. Weinstein practices at the Ankle & Foot Centers of Georgia.

Dr. Matthew Welck, MD, FRCS, of the Royal National Orthopedic Hospital in London, presented on a similar topic at the AOFAS/IFFAS Annual Meeting in Chicago in a lecture titled, “The Metatarsosesamoid ‘The Empty Crista Sign’ – Could This be a Predictor of Deformity Recurrance after Hallux Valgus Surgery?”

Case Study: pedCAT vs. Radiographs

Surgeons often make assumptions based upon plain radiographs.  But plain radiographs often hide or distort significant radiographic findings due to bony superimposition.

Take, for example, the case below:

A patient sought  a second opinion for the cause of her medial foot and ankle pain.  The treating physician used plain radiographs to diagnose her with posterior tibial tendon dysfunction/partial tear and degenerative joint disease of the 1st, 2nd, and 3rd tarsometatarsal joints.  The treating physician also noted a “chip” of bone on the inside of the ankle.

The treating physician planned on performing a flat foot reconstruction, a posterior tibial tendon repair, and a tarsometatarsal joint fusion.

The physician performing the second opinion noted the patient’s discomfort over the medial ankle gutter was much more significant than over the posterior tibial tendon and the spring ligament.  The patient had minimal discomfort through the tarsometatarsal joints. The physician performing the second opinion ordered a weight bearing pedCAT study to assess the midfoot DJD and to better evaluate the midtarsal joint and ankle joint.  The pedCAT study clearly documented a degenerative process in the medial ankle gutter with a bony impingement.  On secondary exam, the majority of the symptoms arose from the medial ankle gutter.

If the flat foot reconstruction was performed as planned, the talus would have been dorsiflexed and the tibio-talar impingement would have been worsened.  The pedCAT images helped prevent an un-necessary surgery, while directing the physician to the appropriate pathology.

tibio talar impingement
The patient was prescribed a pedCAT diagnostic weight bearing CT scan when the patient sought a second opinion.

To learn how more about how the pedCAT could benefit your patients, contact CurveBeam today.