Diagnosis and Management of Acute Ankle Injury with Suspected Achilles Tendon Involvement
This patient most likely has an acute lateral ankle sprain with possible Achilles tendon strain or paratenonitis, and requires immediate plain radiographs using Ottawa Ankle Rules criteria, followed by functional treatment with a lace-up brace, early weight-bearing, and structured exercise therapy.
Immediate Diagnostic Workup
Obtain plain radiographs of the ankle immediately to rule out fracture, as this patient meets Ottawa Ankle Rules criteria with inability to bear weight immediately after injury and pain in the malleolar zone 1. The mechanism—rotational injury with the foot planted—creates high risk for both ligamentous injury and fracture 1.
Key Clinical Findings Supporting Lateral Ankle Sprain:
- Inversion mechanism with foot planted and leg rotating outward is the classic mechanism for lateral ankle ligament injury 1
- Pain with inversion testing indicates lateral ligament complex involvement 1
- Limited range of motion (barely 20 degrees leg lift) suggests significant soft tissue injury and protective muscle guarding 1
- Pain radiating from sole to popliteal fossa may represent referred pain from ankle injury or concurrent Achilles involvement 2, 3
Achilles Tendon Assessment:
The "Achilles heel testing produces pain" is concerning but requires clarification. If this refers to a positive Thompson test (lack of plantarflexion with calf squeeze), this indicates Achilles tendon rupture requiring urgent orthopedic referral 2, 4. However, given the patient can lift her leg (even if limited), complete rupture is less likely 4, 5.
More probable is Achilles tendon strain or paratenonitis given the mechanism and pain pattern, which occurs in two-thirds of Achilles injuries in active individuals 5, 6.
Imaging Protocol
Order AP, lateral, and mortise views of the left ankle as the first imaging study 1. If radiographs are negative but clinical suspicion for significant soft tissue injury remains high (which it does given the severe pain and limited ROM), obtain MRI of the ankle to assess for high-grade ligament tears, osteochondral lesions, and Achilles tendon pathology 1, 3.
Immediate Treatment Plan
Functional Support (First 6 Weeks):
Prescribe a lace-up ankle brace immediately rather than elastic bandage or tape, as lace-up braces reduce swelling 5.48 times more effectively than elastic bandages and 4.07 times more than tape in the first 6 weeks 1. This provides functional support while preserving joint motion 1.
Avoid prolonged immobilization in a cast, as functional treatment with bracing returns patients to work 8.23 days faster and to sports 4.88 days faster than immobilization 1.
Weight-Bearing Protocol:
Allow immediate weight-bearing as tolerated with the brace and crutches 1. Functional treatment with early mobilization significantly improves outcomes compared to immobilization (RR 1.86 for return to sports, RR 5.75 for return to work) 1.
Pain Management:
Prescribe NSAIDs for pain control during the acute phase 1. Ice application (which the patient already attempted) has limited evidence but is reasonable for symptomatic relief 1.
Exercise Therapy Protocol
Refer to physical therapy immediately for structured exercise therapy, as this prevents recurrence (RR 0.37 for preventing future sprains over 8-12 months) 1. Exercise therapy should begin as soon as pain allows and can be performed at home 1.
Specific Exercise Components:
- Balance training exercises to address proprioceptive deficits 1
- Progressive strengthening of ankle musculature, particularly peroneals 1
- Gradual return to functional activities with graded loading 1
Do not use ultrasound, laser therapy, or electrotherapy, as these have no proven benefit in acute ankle injuries 1.
VTE Prophylaxis Consideration
Assess for VTE risk factors given the mechanism of fall and current immobility 7. If the patient meets high-risk criteria (unable to move lower limb independently, prolonged immobility expected), initiate enoxaparin 40 mg subcutaneously once daily after excluding intracranial hemorrhage if there was head trauma 7.
Key high-risk criteria include:
Continue VTE prophylaxis until the patient is independently mobile 7. Early mobilization is mandatory and reduces VTE risk 7.
Return to Activity Timeline
Expected return to light work: 2-3 weeks with mostly sitting work, no lifting >10 kg, and limited standing on uneven surfaces 1. Full return to former work: 3-6 weeks depending on job requirements 1.
Return to sports: 6-8 weeks with functional treatment and appropriate rehabilitation 1.
Critical Red Flags Requiring Urgent Orthopedic Referral
Immediately refer to orthopedics if:
- Positive Thompson test (no plantarflexion with calf squeeze) indicating complete Achilles rupture 2, 4
- Palpable gap in Achilles tendon 4
- Inability to perform single heel raise 2, 3
- Gross ankle deformity or instability 1
Follow-Up Protocol
Schedule follow-up in 5-7 days to reassess pain, swelling, and functional improvement 1. If symptoms worsen or fail to improve with functional treatment after 2 weeks, obtain MRI to assess for high-grade ligament tears or occult fractures 1.
Advise the patient to return immediately if: