Tendon and Ligament Injuries
Tendon injuries typically result from hyperdorsiflexion (peroneal tendon injury) or sudden plantarflexion (Achilles tendon injury). Patients with an Achilles tendon rupture complain of severe pain and are unable to walk on their toes, run, or climb stairs. Ligamentous sprains are caused by inversion and eversion injuries. The most common ankle sprain involves the anterior talofibular ligament. Though an isolated sprain of the medial deltoid ligament is rare, it is occasionally associated with a fibular fracture (Maisonneuve fracture) or syndesmotic ligament injury. Any injury with signs of neurovascular compromise requires immediate attention.
Diagnosis and Differential
Evaluate the ankle as well as the joints above and below the injury. A positive Thompson test (with the patient lying prone and knee flexed at 90°, the foot fails to plantarflex when the calf is squeezed) is diagnostic of Achilles tendon rupture. Palpate the proximal fibula for tenderness resulting from a fracture or fibulotibialis ligament tear. Squeeze the fibula toward the tibia to evaluate for syndesmotic ligament injury. If tenderness is isolated to the posterior aspect of the lateral malleolus, then a peroneal tendon subluxation may be present.
The Ottawa Ankle Rules were developed to help clinicians determine when imaging studies are necessary for patients with ankle injuries (see Fig. 175-1).
Ottawa ankle rules for ankle and midfoot injuries. Ankle radiographs are required only if there is any pain in the malleolar zone or midfoot zone along with bony tenderness in any of these four locations or the inability to bear weight both immediately after the injury and in the ED.
Joint stability dictates the treatment plan for an ankle sprain. Instability is usually suspected based on the physical examination and imaging studies. The examiner may perform the anterior drawer and talar tilt tests to assess stability. If the examiner is unable to perform reliable stress testing, the injury is considered potentially unstable. Asymmetry of the gap between the talar dome and the malleoli on the talus x-ray view also suggests joint instability.
Emergency Department Care and Disposition
If the patient has a stable joint and is able to bear weight, then protection with an elastic bandage or ankle brace, rest, ice, compression, and elevation (PRICE) for up to 72 hours is indicated. Prescribe analgesics, and add motion and strength exercises within 48 to 72 hours. If pain persists beyond one week, the patient should follow up with an orthopedist for a repeat evaluation.
A patient with a stable joint who is unable to bear weight requires an ankle brace, crutches, and orthopedic follow-up.
A patient with an unstable joint requires a posterior splint, crutches, and timely referral to an ...