It's not all black and white

The case

Muscle entrapment after orbital fracture usually involves the inferior rectus, while solitary inferior oblique entrapment is uncommon. In this case, solitary inferior oblique entrapment clinically mimics Brown's syndrome.

A patient with traumatic Brown's syndrome is more likely to complain of pain in the region of the trochlea, while the elevation deficiency produced by a blow-out fracture is usually more marked in abduction rather than adduction.²

How do we treat it?

There is no consensus on the optimal treatment for blowout fractures. Some authors recommend early surgical therapy while others advocate surgery only when conservative therapy has been ineffective. Diplopia persists in a significant number of patients following surgical treatment of a blowout fracture of the orbital floor, even when surgery is performed within 15 days after the traumatic incident.³ Our patient was managed conservatively and, after eight weeks, his diplopia was resolved with full recovery of ocular motility (Figure 3).

The case clearly highlights how inferior oblique muscle entrapment in an orbital floor fracture can mimic Brown's syndrome. These restrictive conditions are very similar clinically; therefore, attention to the nature of injury and imaging study are crucial to differentiate these two circumstances.