CAT SUMMARY ESSAY
You review the electronic health record (EHR) with Dr. Nayar and consider which aspects of the past medical history you will want to obtain from Christina.
Chief Concern: 19-year-old female presenting with right ankle pain.
Problem List:
Otitis Media (age 2)
Mononucleosis (age 14)
Left radial head fracture (age 15)
You refer to the CDC Immunization schedule to identify if Christina is overdue for any immunizations. After reviewing her immunization record, you conclude that she is up to date on all recommended shots.
TEACHING POINT
Past Medical History
All portions of the past medical history including medical problems, surgeries, food and medicine allergies, and social history are important.
Often, the immunization history is overlooked when patients don’t come in expressly for a prevention visit. But, the immunization history is significant, even in an acute visit, as another opportunity to update immunizations may not present itself for a while.
You go to the exam room and introduce yourself to the patient, Christina, and her mother, Mrs. Martinez. You then begin to interview Christina about the mechanism and timing of her ankle injury.
“Can you tell me more about how you hurt your ankle?”
Tearfully, she elaborates, “I was playing soccer last night and was trying to pass the ball to a teammate. Somehow I slipped and fell.”
“Do you know which way you fell on your ankle?”
Christina says, “My ankle really hurts along the outside. I am having a lot of problems walking and it’s a little stiff. It was swollen yesterday.” Mrs. Martinez adds, “I saw her ankle twist inward as she fell to the ground. The coach immediately iced the area and she was able to leave the field under her own power.”
“Have you ever had other difficulties with your ankle?”
“No, this is the first time anything like this has ever happened.”
“Do you have other health concerns you would like to address today?”
“Actually, I have been having problems when I pee, but I want to talk about my ankle first.”
Given this information, you suspect Christina’s injury is probably moderate. You refocus and plan to follow up by asking questions to eliminate concern about a limb-threatening injury.
TEACHING POINT
Significance of Historical Features of Ankle Injury
A patient who seeks help immediately, and is non-weight bearing, is more likely to have a severe injury than one who presents a few days after an incident and is fully weight-bearing (the ability to take four steps independently).
A history of previous ankle sprain is a common risk factor for an ankle injury.
While hearing a snap or tear is diagnostically significant in an acute knee injury, it is not in an acute ankle injury.
Differential of Acute Ankle Pain Following Inversion Injury
Acute ankle injury is one of the most common musculoskeletal injuries in athletes and sedentary persons, accounting for an estimated 2 million injuries per year and 20% of all sports injuries in the United States.
There are many potential reasons for ankle pain.
Achilles tendon rupture
A common sports injury classically associated with an audible “pop.” Incidence increases with age. Patients are unable to plantarflex.
Fibular fracture
Usually due to a fall, an athletic injury, or a high-velocity injury such as a motor vehicle accident. Patient may have severe pain, swelling, inability to ambulate, and deformity. The Ottawa ankle rules help to distinguish patients who need an x-ray to rule out such a fracture.
Lateral ankle sprains
Generally present acutely (after trauma) with pain, warmth, and some swelling. Ankle sprains do not create a deformity. If there is a large amount of swelling present, however, it may appear to be a deformity.
Medial ankle sprain
Somewhat rare and suggests that forced eversion has occurred. There is typically injury to the deltoid ligament.
Osteoarthritis of the ankle
Less common than in some other joints. It is a chronic process, more commonly seen in older people. The tibiotalar joint is generally involved and the condition may occur as a result of prior injury, obesity, or history of rheumatoid disease. Symptoms may include stiffness, swelling, deformity, and a feeling of instability.
Peroneal tendon tear
Typically due to an inversion injury and may occur in conjunction with a lateral ankle sprain. Patient may complain of persistent pain posterior to the lateral malleolus. Swelling may or may not be present. Repetitive trauma may cause injury to the peroneal tendons.
Syndesmotic sprain
Generally involves the interosseous membrane and the anterior inferior tibiofibular ligament. Pain and disability are often out of proportion to the injury. One would expect a positive ankle squeeze test.
Mechanism of Injury and Anatomy of Ankle Sprains
Plantar flexion and inversion
The most common mechanism of injury in ankle sprains is a combination of plantarflexion and inversion. The lateral stabilizing ligaments, which include the anterior talofibular, calcaneofibular, and posterior talofibular ligaments, are most often damaged.
The anterior talofibular ligament is the most easily injured. Concomitant injury to this ligament and the calcaneofibular ligament can result in appreciable instability. The posterior talofibular ligament is the strongest of the lateral complex and is rarely injured in an inversion sprain.
The anterior drawer test can be used to assess the integrity of the anterior talofibular ligament, and the inversion stress test can be used to assess the integrity of the calcaneofibular ligament.
Excessive eversion and dorsiflexion
In medial ankle sprains, the mechanism of injury is excessive eversion and dorsiflexion. Medial ankle stability is provided by the strong deltoid ligament, the anterior tibiofibular ligament, and the bony mortise. Because of the bony articulation between the medial malleolus and the talus, medial ankle sprains are less common than lateral sprains.
Question
What are the signs/symptoms that are included in determining the grade of an ankle sprain?
Select all that apply.
The best options are indicated below. Your selections are indicated by the shaded boxes.
A. Ecchymosis
B. Ligament tear
C. Loss of functional ability
D. Pain
E. Swelling
SUBMIT
Answer Comment
The correct answers are A, B, C, D, E.
All of these elements—in addition to whether the patient can bear weight—are used to grade an ankle sprain. See Teaching Point below.
TEACHING POINT
Grading Ankle Sprains
Grading of ankle sprains takes into consideration:
The presence/absence of a ligament tear
Loss of functional ability
Severity of pain
Presence and/or severity of swelling
Presence of ecchymosis
Difficulty bearing weight: the ability to take four steps independently
Grade I sprain involves stretching and/or a small tear of a ligament. There is mild tenderness and swelling, slight to no functional loss, and no mechanical instability. No excessive stretching or opening of the joint with stress.
Grade II sprain is characterized as an incomplete tear and moderate functional impairment. Symptoms include tenderness over the involved structures, mild to moderate pain, swelling, and ecchymosis. In this grade, there is some loss of motor function and mild to moderate instability. Stretching of the joint with stress, but with a definite stopping point.
Grade III sprain is characterized as a complete tear and loss of integrity of the ligament. Severe swelling (greater than 4 cm about the fibula) and ecchymosis may be present, along with an inability to bear weight and mechanical instability. Significant stretching of the joint with stress, without a definite stopping endpoint.
Please note that clinical grading of lateral ankle sprains may be limited based on a number of factors including patient pain level, interexaminer reliability, and the subjective nature of using visual inspection findings to establish an accurate diagnosis. Initial management amongst each grade of lateral ankle sprains will likely depend more on other factors individualized to a given patient and their symptoms.
The next step you would like to take to work up Christina’s symptoms is to see if you can elicit any costovertebral angle (CVA) tenderness and examine her abdomen. You tap on Christina’s back below the ribs on both sides and elicit no expression of tenderness. She does not have suprapubic tenderness, rebound, or guarding.
Mrs. Martinez wants to know, “What do you think is going on?”
Dr. Nayar asks you,
“So what grade of ankle sprain do you think Christina has?”
You reply, “I am not sure. Christina has some loss of functional ability and pain. She had swelling on the first day, but none now. There isn’t any bruising on exam, but she does not want to weight bear. I’m having trouble deciding between Grades I and II. In the end, I would say Grade I because Christina has persistent pain, previous swelling that has resolved, tenderness, and mild to moderate inability to function.”
He agrees and adds,
“Do you think we should get an x-ray to rule out a fracture?”
“I’m pretty sure she just has a sprain. But Mrs. Martinez was very firm in wanting Christina to have an x-ray. I’m not really sure what the best thing to do is.”
TEACHING POINT
Deciding When Foot/Ankle Radiography Is Indicated – Ottawa Ankle Rules
Ankle injuries are the most common presentation to the emergency department, yet less than 15% of these injuries turn out to be clinically significant fractures.
The Ottawa rules are evidence-based tools developed to help physicians decide when radiography is indicated.