Assessing musculoskeletal pain: the ankle SOAP note case

Two details in four lines of history do most of the diagnostic work, and a note that does not use them has missed the case. She *heard a pop*, which raises ligamentous rupture or tendon injury rather than a simple strain; and she *is able to bear weight*, which is the single most important negative in the vignette because it feeds directly into the Ottawa ankle rules the brief goes on to ask about. Note also that pain is bilateral while concern is unilateral — which means an acute right-sided injury sits on top of something chronic and bilateral, and a good note asks what that background is rather than treating the left ankle as noise. Ask about previous ankle injuries explicitly, because recurrent sprains are the commonest cause of chronic instability and would explain both the bilateral pain and why this one happened.

The anatomy question is asking for named structures, not regions. The mechanism of a soccer injury with a pop is most often inversion, which loads the lateral ligament complex: the anterior talofibular ligament first, then the calcaneofibular, then the posterior talofibular. Eversion injuries load the deltoid ligament medially. A high ankle sprain involves the syndesmosis and the anterior inferior tibiofibular ligament, presents with pain above the joint line, and takes far longer to recover — which is why it must be looked for rather than assumed absent. Peroneal tendons, the Achilles, and the base of the fifth metatarsal complete the list of structures that plausibly produce an audible pop. Name the structure you think most likely and say why, since a list of everything that could produce a pop is a knowledge display rather than an assessment.

The Ottawa ankle rules deserve a direct answer rather than a mention, because the brief asks *should you apply them* and the honest answer engages with what they are for. They are a validated decision rule with very high sensitivity for clinically significant fracture, designed to reduce unnecessary radiography — so their value is in safely ruling out, not in ruling in. Applying them means checking bony tenderness at the posterior edge or tip of either malleolus, at the navicular, at the base of the fifth metatarsal, and the ability to take four steps. Her being able to bear weight satisfies one criterion; the others still have to be examined, and saying that shows you understand the rule as a set of findings rather than as a yes or no. Say what you would do if a criterion were positive, because a decision rule with no stated consequence has been recited rather than applied.

The brief asks for **five** differentials, each justified — a higher number than most cases demand, and enough that a lazy list runs out at three. Build the set across categories rather than listing grades of the same injury: a lateral ligament sprain as the most likely; a syndesmotic injury because it changes management and recovery time; a fracture, most usefully the avulsion of the fifth metatarsal base or a distal fibular fracture; peroneal tendon subluxation or tear, which explains the pop; and one that addresses the bilateral background, such as osteoarthritis, inflammatory arthropathy, or chronic ankle instability from prior sprains. Justify each on findings present and findings absent. Ordering them by likelihood also helps, since a marker reading five differentials wants to know which one you are actually treating while the others are excluded.

On format: the brief is explicit that this is an *Episodic/Focused SOAP note*, not a narrative discussion post, and that all such notes have specific data in every section. That means subjective content that includes the mechanism, onset, aggravating and relieving factors and prior injury history; objective content limited to what you examined, including inspection, palpation of the named landmarks, range of motion, neurovascular status and the special tests — anterior drawer, talar tilt, squeeze and external rotation for syndesmosis, and Thompson if the Achilles is in question. Each diagnostic test you propose needs literature support, which the brief states as a requirement rather than a suggestion. Keep Assessment and Plan separate from Objective too, because the commonest structural error in these notes is a diagnosis appearing in the examination findings.