When should I consider referring a patient with an ankle sprain for imaging studies such as an X-ray or MRI?

Consider referring a patient with an ankle sprain for imaging studies such as an X-ray if:

• There is suspicion of a fracture or dislocation, guided by clinical decision rules such as the Ottawa ankle and foot rules for patients over 5 years old.
• There are signs of damage to nerves or circulation, wound penetrating the joint, known bleeding disorder, or serious complications like haemarthrosis or septic arthritis.
• Symptoms are out of proportion to the mechanism of injury or degree of trauma, or if recovery is slower than expected with worsening or new symptoms.

MRI should be considered in cases of:

• Suspected high-grade ligament injuries, osteochondral defects, or occult fractures, especially if symptoms persist despite conservative treatment.
• Chronic ankle instability to rule out missed syndesmotic injuries or bony injuries not identified on X-ray.
• Professional athletes with severe injuries where quicker return to play is desired.

Routine MRI is not recommended for all acute ankle sprains due to high cost, limited availability, and false-positive findings; it is reserved for persistent or severe cases.