Lateral ankle sprains are one of the most common injuries seen in orthopedic practice. In fact, an estimated 9 million ankle sprains occur annually in the United States. Most mild ankle sprains heal uneventfully in 4 to 6 weeks with a brief period of immobilization. Severe ankle sprains may take up to 3 months to heal and are more prone to recurrent instability, particularly if rehabilitation is not carried out appropriately. A small percentage of those who sustain an ankle sprain will have chronic instability, with feelings of the ankle “giving way.” People with chronic symptoms often complain more about instability than about pain. In those with chronic symptoms, associated injuries such as osteochondral injuries, arthritis, loose bodies, and peroneal tendinopathy must be ruled out. Magnetic resonance imaging is often ordered to rule out other pathology.1,2

Modified Brostrom is the most common surgical procedure performed for chronic instability of the ankle. The modified Brostrom procedure involves repairing or tightening the anterior talofibular ligament (ATFL) and the calcaneofibular ligament (CFL) to the fibula. Isolated injury to the ATFL occurs with most (65%) ankle sprains, and both the ATFL and the CFL are involved in 20% of ankle sprains. The modified Brostrom procedure tightens the lateral ligaments, which reduces lateral instability when the foot is in plantar flexion and inversion (typical mechanism of an ankle sprain). Postoperatively, a 2- to 4-week period of immobilization followed by 2 to 3 months of rehabilitation is recommended. Athletes can often return to sports 4 months after the procedure.2

Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor-in-chief of the Journal of Orthopedics for Physician Assistants (JOPA).


  1. Polzer H, Kanz KG, Prall WC, et al. Diagnosis and treatment of acute ankle injuries: development of an evidence-based algorithm. Orthop Rev (Pavia). 2012;4:e5.
  2. Wukich DK, Tuason DA. Diagnosis and treatment of chronic ankle pain. Instr Course Lect. 2011;60:335-350.
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