Likely Diagnosis: Anterolateral Ankle Impingement Syndrome
Given the sudden onset of stabbing, spasmodic pain in the anterolateral region above the ankle that completely resolves after hours and does not return, the most likely diagnosis is anterolateral soft tissue impingement syndrome, possibly triggered by a minor inversion injury or repetitive microtrauma. 1, 2
Clinical Reasoning
Why This Presentation Suggests Impingement Rather Than Other Causes
Self-limiting nature: The complete resolution of symptoms after several hours without recurrence strongly argues against acute limb ischemia, compartment syndrome, or stress fracture—all of which would persist or worsen without intervention 3, 4
Location specificity: Anterolateral ankle pain above the joint line is the classic presentation of anterolateral impingement, where hypertrophic soft tissue or scar tissue becomes transiently trapped between the talus and lateral malleolus during certain movements 1, 5
Pain character: The "stabbing, spasmodic" quality matches the mechanical entrapment pain described in impingement syndromes, which occurs when soft tissue is pinched during specific ankle positions and releases when the position changes 2, 6
Key Distinguishing Features from Serious Pathology
Acute limb ischemia excluded: The absence of the "6 Ps" (pain, paralysis, paresthesias, pulselessness, pallor, poikilothermia) and complete symptom resolution rules out vascular emergency 3
Compartment syndrome excluded: Pain that completely subsides contradicts compartment syndrome, where pain is progressive and "out of proportion" to injury, with passive stretch pain being the most sensitive early finding 4
Stress fracture unlikely: Tibial stress fractures cause persistent pain that worsens with weight-bearing and does not spontaneously resolve after hours 4
Mechanism and Pathophysiology
Anterolateral impingement begins with ligamentous injury (anterior talofibular or calcaneofibular ligament) that may not cause chronic instability but leads to chronic inflammation and scar tissue formation 1
This hypertrophic tissue becomes intermittently trapped in the lateral gutter during certain movements (typically dorsiflexion with inversion), causing acute pain that resolves when the ankle moves out of the impinging position 1, 2
The transient nature of symptoms occurs because the soft tissue entrapment is position-dependent—when the ankle moves away from the provocative position, the tissue is released and pain immediately improves 2, 6
Clinical Evaluation to Confirm Diagnosis
Palpation findings: Tenderness at the anterolateral joint line, specifically over the lateral gutter between the lateral malleolus and talus 2, 5
Provocative maneuvers: Pain reproduction with forced dorsiflexion combined with inversion, simulating the impingement position 2, 6
Absence of instability: Unlike chronic ankle instability, impingement patients typically have stable ligaments on anterior drawer and talar tilt testing 1
Swelling pattern: Mild localized swelling may be present at the anterolateral joint line, but significant diffuse swelling suggests alternative diagnosis 2, 5
Diagnostic Imaging Approach
Plain radiographs first: Obtain anteroposterior, lateral, and oblique views to exclude bony impingement (osteophytes), fractures, or loose bodies 2, 6
MRI if diagnosis unclear: Consider MRI if symptoms persist beyond 6-8 weeks of conservative treatment or if clinical examination is atypical, though imaging is often normal in early soft tissue impingement 7, 2
Arthroscopy as gold standard: Direct visualization remains the definitive diagnostic and therapeutic modality, allowing identification of hypertrophic synovium, scar tissue, or meniscoid lesions 5, 6
Initial Management Strategy
Relative rest and activity modification: Avoid provocative positions (dorsiflexion with inversion) while maintaining general ankle mobility to prevent stiffness 8, 7
NSAIDs for short-term relief: Use for 7-14 days to reduce inflammation, though they do not alter long-term outcomes in tendinopathy-related conditions 8
Physical therapy modalities: Ice therapy (10-minute periods through wet towel, multiple times daily) and progressive strengthening exercises once acute symptoms subside 7, 1
Eccentric strengthening: Initiate when pain allows to address any associated peroneal tendinopathy and improve dynamic ankle stability 8, 7
When Conservative Treatment Fails
Arthroscopic debridement indicated: If symptoms persist beyond 3-6 months of appropriate conservative management, arthroscopic removal of impinging tissue provides good-to-excellent results in 83-91% of patients 2, 5
Surgical outcomes: Average AOFAS scores improve from 34 preoperatively to 89 postoperatively, with most patients returning to previous activity levels 5
Low morbidity procedure: Arthroscopic approach offers short recovery time and high patient satisfaction, with 22 of 23 patients in one series willing to undergo the same procedure again 5, 6
Critical Red Flags Requiring Urgent Evaluation
Persistent or worsening pain: If pain does not resolve or progressively worsens, immediately reconsider vascular causes (acute limb ischemia) or compartment syndrome 3, 4
Neurovascular compromise: Any signs of motor weakness, sensory loss beyond the toes, absent pulses, or pallor require emergent CT angiography and vascular surgery consultation 3
Systemic symptoms: Fever, erythema, or warmth suggests infection requiring immediate evaluation 7