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“DOCENDO DECIMUS”

DCMC Emergency Department Radiology Case of the Month

These cases have been removed of identifying information. These cases are intended for peer review and educational purposes only.

Welcome to the DCMC Emergency Department Radiology Case of the Month!

In conjunction with our pediatric radiology specialists from ARA, we hope you enjoy these monthly radiological highlights from the case files of the Emergency Department at DCMC. These cases are meant to highlight important chief complaints, cases, and radiology findings that we all encounter every day.

If you enjoy these reviews, we invite you to check out Pediatric Emergency Medicine Fellowship Radiology rounds, which are offered quarterly and are held with the outstanding support of the pediatric radiology specialists at Austin Radiologic Association.

If you have and questions or feedback regarding the Case of the Month format, feel free to email Robert Vezzetti, MD at rmvezzetti@seton.org.

This Month: Knee pain is a common complaint in Pediatrics and the majority of these children have sprains and strains. The patient in this month’s newsletter has an interesting, not run of the mill, cause of her knee pain and swelling. Enjoy…

Conference Schedule: December 2016

7th - 8:00 Toxicology/Toxidromes...............Drs Earp and McClung 9:00 Simulation: Toxicology......................Simulation Faculty 14th - 9:15 M&M……….................................Drs Bahling and Salinas 10:15 Board Review: Dermatology…..…………........Dr Levine 12:00 ED Staff Meeting

21st: CHRISTMAS BREAK NO CONFERENCE

28TH: NEW YEAR'S BREAK: NO CONFERENCE

Simulations are held at the CEC at UMC Brackenridge.

Lectures are held at DCMC Command Rooms 3&4.

This year, the total cost of all the items mentioned in the 12 Days of Christmas, from the partridge to the drummer drumming, totaled $34, 363.49. This is a total increase of 0.7% from last year and is mostly attributed to the lack of turtledoves in the market

However, since there are multiples of each item in the song, the grand total is $ 156, 507.88. This index is

complied by PNC and based on real prices.

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Case History

It’s been a relatively subdued November in the Pediatric ED. Since there hasn’t been much influenza (or RSV for that matter), you have mostly been seeing injuries. What? Yep; the weather has been so nice and mild that the pediatric population is out, about, and active. That’s why, when you pick up the next chart, you are not surprised to see the chief complaint: left knee pain.

You go into the room and find a well-appearing, nontoxic, 14 year old female who does not appear in any acute distress whatsoever. In fact, you wonder why the child is in the Emergency Department in the first place. Then, the child’s mother begins the tale.

This teenager has had left knee pain and edema for the past 4 weeks, but the symptoms have worsened over the past 2 weeks. That’s pretty much it. The child endorses no history of trauma. She and her mother both deny fever, erythema, tingling, numbness, or weakness. There is no history of back pain, other joint edema, or rashes. There is no travel history. They also state that the child is extremely healthy and is an active dancer. Yet, when asked for a second time, the strenuously deny any trauma history. She is able to ambulate and even has been continuing to dance, but the past few days have been particularly worse with regard to her symptoms and she has had pain while ambulating. The pain is described and achy and diffusely located over the knee. If you ask her to try to pinpoint where the pain is the worst, she states in the “front of the knee.” Not helpful…

Her vitals signs look perfectly normal: Temp - 98.8 HR - 89 RR - 20 BP - 112/77. Her physical examination is remarkable only for her left knee. There is obvious edema of the whole of the knee. The knee appears to be aligned. There is no ecchymoses, erythema, abrasions, or lesions. Palpating the knee, you note a moderate joint effusion and very mild warmth. She has generalized tenderness of the knee and her range of motion is restricted by pain. When encouraged, though, she is able to fully extend and flex the knee, with the production of some pain. The joint appears to be stable when you try anterior and posterior drawer tests, although she states it hurts when you perform this exam. She does not have a positive patellar apprehension test. Her Lachman test is negative. She does not have crepitus. Additionally, there is no crepitus and there are no palpable masses. She is neurovascularly intact.

Her mother reveals to you that they have been seen multiple times by her family physician and have had several films of the knee done. Most recently, the child was seen at an urgent care center, where a left hip film was done; this was reported to the mother has being “normal.” Of course, you do not have the images to review.

Now what? Imaging?

A Charlie Brown Christmas is a holiday classic! The animated special first aired in 1965 is uber popular and is the second longest running animated special, right behind Rudolph the Red nosed Reindeer.

Like most TV shows in the 60’s Merry Christmas Charlie Brown was supposed to have a laugh track! Charles Shultz nixed that idea very promptly. Good thing!

The show practically killed the aluminum Christmas tree, which was popular from 1958-1963. By 1967 (2 years after the show aired, they were no longer produced!

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A good knee exam is important when treating patients with knee complaints. Here’s one approach:

Observation: It’s helpful to begin with a general inspection of the knee, looking for obvious edema, erythema deformities, etc. It helps to observe the child while both standing and walking (if they are able) to look for symmetry, patella position, knee angle, masses, or effusions.

Palpation: Is there edema, warmth, tenderness? Is there an effusion? You can look for a fluid wave (done by extending the knee and compressing the supra patellar region. The presence of a wave suggests an intra-articular injury, especially in the setting of trauma.

Manipulation: Is the patella and knee joint stable? Children often have lax ligaments and the patella can be mobile. It is helpful to compare both the affected knee and the unaffected to knee to see if what appears to be a hyper mobile patella is actually normal for the child.

Posterior Drawer Test Anterior Drawer Test

Lachman TestMcMurray Test

Various Knee Exam Maneuvers Anterior Drawer Test: With the knee flexed to 90 degrees, the patient supine, the foot flat, grasp the tibia just below the joint . Place your thumbs on the joint line. Pull the tibia forward. An increased amount of laxity (compare to the other side!) is suggestive of an anterior cruciate ligament tear.

Posterior Drawer Test: The technique is the same, except the tibia is pushed backward A positive test suggests an injury the posterior cruciate ligament.

Lachman Test: Used to assess an injury to the anterior cruciate ligament and considered more sensitive than the anterior drawer test. The patient is supine with the knee flexed 20-30 degrees; place one hand behind the tibia (with the thumb on the tibial tuberosity) and the other grasping the patient’s thigh. Pull the tibia forward. More than 2 mm of anterior translation (compared to the other knee) is considered positive.

McMurray Test: Evaluates meniscus injuries. Hold the knee in one hand while the leg is flexed, rotating the foot. Pain or a click is a positive test.

The McMurray Test is named for Thomas Porter McMurray (1887-1949), a British Orthopedic (or Orthopaedic) surgeon. He was known to be extremely fast and could remove a meniscus in 5 minutes (without arthroscopy!).

The Lachman Test is maned for John Lachman, Chairman of Orthopedics at Temple University School of Medicine.

Dr LachmanDr McMurray

While the actors that voiced Charlie Brown, Linus and Lucy were professional child actors, the rest of the Peanuts cast voices were done by children from director Bill Melendez’s California neighborhood. Some couldn’t read and had to have their lines recited to them.

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Because you can’t see the previous images, you decide to order some new ones. You start with a knee series as well as hip views, recalling that knee pain in pediatrics is often referred pain from the hip, especially in SCFE or LCP Disease, or in cases where there are avulsion fractures of the pelvis (see December 2015 for a discussion of these clinical entities).

Imaging the knee is usually done with 2 views:

AP View : Done with the patient supine and the leg fully extended. Assesses the knee joint, distal femur, proximal tibia/fibula and patella.

Lateral View: Done with the patient supine and the knee slightly flexed (ideally 30 degrees). Assess lipohemarthrosis and, in the setting of acute trauma, is ideal.

There are other specialized views that can be obtained:

Sunrise View: This view is included on a “3 view series” and is often done in the setting of trauma. This view is very helpful when a patellar fracture os dislocation is suspected and the AP/Lateral views look normal.

The images above and to the right show normal AP and Lateral views of the knee. When looking at knee films: 1. Make sure it’s the right patient! 2. Look at the AP view and assess tibiofemoral alignment

(a line drawn from the lateral margin of the lateral femoral condyle..if the tibia is greater than 5 mm outside of the line, think a tibial plateau fracture, red line).

3. Look for effusions of the lateral view; hemarthrosis suggests ligamentous/meniscus injury, fat suggests intra-articular injury).

This film shows lipohemarthrosis. From: radiopaedia.org

Segond Fracture This is an avulsion fracture of the knee, usually on the lateral aspect of the tibia. Most often it is associated with a disruption of the ACL. Often this is the result of falls of sports (skiing especially). There is extensive ligamentous injury associated with this fracture and requires surgical repair. This injury was described by French surgeon Paul Second (1851-1912).

Dr Segond: OB/GYN, knee expert, and published on prostate abscesses!

I love the music off Vince Guaraldi, who gave us memorable songs like Linus and Lucy and Skating. He was responsible for the music heard in all the Peanuts animation specials. Interestingly, Charles Schultz hated jazz, but liked Guaraldi’s music, and the rest is history.

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Back to our patient…So here are the knee images from a 3 view knee X-ray that was obtained. There is no obvious fracture or dislocation. The tibiofemoral line is normal. There is no evidence of a mass, hemarthrosis, or foreign body. There is a very small amount of joint fluid in the supra patellar bursa (red arrow) but really, this is an overall normal film. The selected frog leg film is normal.

So now the question is what to do next. The child can be discharged and followup with Pediatric Orthopedics, with a knee immobilizer and crutches, as well as symptomatic care. You explain this to the mother, and then she tells you she is extremely worried..the pain is worsening!

Not the best frog leg , but overall the film is normal.

Here is a sunrise, view, so named because the patella looks like the sun rising. Looks normal. No evidence of fracture.

CT vs MRI for Knee pain or injury: Both modalities can be used but it depends on what you’re looking for. MRI is the gold standard and can assess ligaments, the menisci, chondral and subcentral lesions. CT is useful in the setting of acute trauma, especially with fractures.

In 2015, the US Postal Service issued a set of ten postage stamps with various scenes from the TV special, to celebrate its 50th anniversary.

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So now you have a very anxious mother and a child with chronic knee pain and what are essentially normal films. The child really does need Pediatric Orthopedic followup. There are no signs of infection on exam and the child does not appear to have a mass or other concerning findings on plain films. Further imaging may be indicated, and this can certainly be done as an outpatient. The mother is obviously not happy with this, despite your explanations and reassurances. You decide to see if you might be able to obtain an MRI while the child is in the ED. Oddly enough, the scanner is open and, since this will be a relatively quick study that does not require sedation, you can obtain one tonight. You explain to the mother that this NEVER happens, but you’re getting an MRI of the knee, with and without contrast.

Well, here is the MRI that you were able to obtain. These selected images here show the study which was done both with and without IV contrast.

There is a 9mm by 3.9 mm by 7.5 mm focus of osseous subchondral signal abnormality (red arrow). There is surrounding edema signal in the adjacent bone marrow as well (blue arrow). The majority of the overlying cartilage appears intact. The ligaments are all normal. The supra patellar bursa has a small amount of fluid (yellow arrow) but there is not a significant joint effusion.

This study is consistent with osteochondritis dissecans, which is osteonecrosis of the subchondral bone, which is due to the subchondral bone and articular cartilage separation from the underlying bone, leaving a fragment that is not stable. There are multiple classification systems that are used to described the extent of displacement of the fragment. Symptoms of this disease consist of progressively worsening joint pain over several months. Tenderness on exam is typical and, as the disease progresses, locking or popping of the knee is not uncommon. Sometimes the diagnosis can be made on plain radiographs. In cases that are not clear, MRI may be helpful. Contrast is not needed, unless there is suspicion of infection or other inflammatory processes. Treatment consists of nonoperative options, such as restriction of activities, immobilization, and physical therapy. Pain can be helped with NSAIDS. Operative management is suggested when nonoperative management is not helping, or if there is advanced disease, especially in skeletally immature patients. The prognosis for recovery and resumption of normal activities is dependent on disease stage and skeletal maturity.

“When they first saw the show, CBS executives were horrified at the idea of an animated Christmas special with such a blatant message. They also strongly objected to the fact that the show had no canned laughter. In addition, they greeted Vince Guaraldi’s jazz score as an intrusion in the special that audiences would never accept.” -IMDB.com

This can be seen sometimes on plain radiography (yellow arrow). The condition is not limited to the knee; it has been described in the elbow (blue arrow) and the talus of the ankle. Clinical presentation in those areas is like that of the knee: pain and swelling. By the way, the conditions bilateral 25% of the time!

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Teaching Points1. A good knee examination is key! Learning simple exam techniques can provide a lot of information to the clinician. Don’t forget hip pathology

when evaluating knee pain in children!2. Plain radiography is a good initial imaging choice in knee evaluation. Two views of the knee are typically suficient. The sunrise view of the patella

can help identify patellar fractures as well when there is clinical suspicion.3. If plain radiographs are normal and there is still suspicion of a fracture, or to delineate complex knee fractures, a non contrast CT scan is an

excellent choice. Most often used in trauma cases.4. Knee MRI is a gold standard test that can usually be obtained on an outpatient basis. It is excellent to identify ligamentous and meniscal

injuries. Use contrast enhanced imaging when inflammatory or infectious etiologies are being considered.5. Prompt Pediatric Orthopedic referral is key to maximizing good outcomes. Immobilization (usually with a knee immobilizer or split) and rest until

followup is arranged is a wise course of action.

Case ResolutionThe mother and the child were both very grateful that an answer was finally given to them and one that can be easily treated. The child was placed in a knee immobilzer, given crutches, instructions for rest as well as NSAIDS; Pediatric Orthopedic followup was arranged. As of this writing, she is currently doing well and will likely respond to physical therapy.

REFERENCES 1. Solomon, D. H.; Simel, D. L.; Bates, D. W.; Katz, J. N.; Schaffer, J. L. (2001). "The rational clinical examination. Does this patient have a torn meniscus or

ligament of the knee? Value of the physical examination". JAMA: the Journal of the American Medical Association. 286 (13): 1610–1620. 2. Robertson W, Kelly BT, Green DW. Osteochondritis dissecans of the knee in children. Curt Opin pediatric. 2003; 15:38. 3. Edmonds EW, Polonsky J. A review of knowledge in osteochondritis dissecans: 123 years of minimal evolution from Konig to the ROCK study group. Cain

Orthop Relat Res. 2013; 471:1118. 4. Krause M, Hapfelmeier A, Moller M, et al. Healing predictors of stable juvenile osteochondritis dissecans knee lesions after 6 and 12 months of

nonoperative treatment. Am J sports Med. 2013; 41:2384. 5. Kocher MS, Tucker R, Manley TJ, et al. Management of osteochondritis dissecans of the knee: current concepts review. Am J Sports Med. 2006; 34:1181. 6. Kalke RJ, Di Primno GA, and Schweitzer ME. MR and CT arthrography of the knee. Semi Musculoskelet Radiol.. 2012. 16(1):57. 7. Hirschmann A and Hirschmann MT. Chronic knee pain: clinical value of MRI versus SPECT/CT. Semi Musculoskeletal Radiol. 2012. 20(1):3.

DCMC Radiology Case of the Month 2016 Index

Jan - Cough in Pediatrics Feb - Abdominal Trauma: Renal Laceration; Chance fx March - Abdominal Mass: Infected tracheal remnant April - Pediatric Elbow Fractures May - Abdominal Pain: Pancreatoblastoma June - Bell’s Palsy with Apicitis and Epidural Abscess July - Pediatric Shoulder Injuries August - Orbital Cellulitis September - Imaging Pediatric Ingestions Hydrocarbon Non radio-opaque Foreign Bodies October - Hematometra/Hematocolpos November - Open Complex facial/forehead fracture December - Knee swelling: osteochondritis dissecans

Have a Safe and Happy Holiday Season!We will see you in 2017!

Coca-Cola was the original sponsor of the show and several sections during the special featured the Coca-Cola logo prominently displayed. (Linus even crashes into a Coke sign while skating). A the end of the credits was the message: “Merry Christmas from your local bottler of Coca-Cola!” All of this was edited out after the original broadcast.

Here are the various grade of osteochrondritis dissecans lesions. The picture is an intra-operative image of a Grade IV lesion (from: Consultant For Pediatrician, web content). The greater the grade of lesion, the more likely operative repair will be needed.