Orbital lesions are frequent findings after blunt periocular trauma causing diplopia, muscle avulsion etc.  Four patients presented with diplopia after a penetrating injury to the right eye. Examination revealed right hypertopia and limitation of infraduction of right eye with rupture of Inferior Rectus. Immediate repair of inferior rectus muscle with anterior transposition of inferior oblique is a safe and effective procedure to restore motility

Orbital trauma is associated with various periorbital and ocular injuries, causing diplopia, muscle avulsion and/or incarceration, paralysis and scar adhesions. In cases of vertical diplopia, rupture of the inferior rectus muscle (IR) secondary of trauma is an infrequent finding, yet possible cause of persistent infraduction deficit. Also it has been seen that traumatic muscle laceration involves the inferior or medial rectus muscles more often. Hypertropia with lack of infraduction following trauma is a diagnostic feature. Persistent Defect leads compensatory changes, posing a surgical challenge later on, so standard procedure includes repair of flap tear, transposition of horizontal recti, and reattachment of distal end to proximal connective tissues. Inferior oblique transposition is not much reported in literatures. Here we present four cases of traumatic inferior rectus muscle laceration which was corrected with anterior transposition of inferior oblique to the snapped inferior rectus muscle stump. [1, 2]

Four cases of traumatic inferior rectus laceration were isolated among orbital trauma patients. All patients had hypertropia with lack of infraduction which was diagnostic of trauma to inferior rectus. Infraduction of the affected eye was markedly reduced. Forced-duction testing showed no limitation to elevation and infraduction in the affected eye, suggesting an isolated lesion of IR with no entrapping of orbital tissue and associated muscle. To restore the function anterior transposition of inferior oblique muscle to IR was planned. Under local anaesthesia IR muscle was explored and in all three cases and only the proximal stump of snapped IR could be found. Inferior oblique muscle was anteriorly transposed at the distal stump of inferior rectus. Traction suture was given which was removed after 10 days. Figure: [1, 2, 3, 4, 5, 6, 7&8]

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Two weeks after surgery restoration of motility in all the three cases who underwent repair promptly after injury was seen, but partial recovery in the fourth case. Primary repair in the fourth case involved only repair of distal stump without any transposition. Delayed transposition was difficult and less effective.

In the literature range of ocular injuries following orbital trauma is well described. [3, 4] Rupture of IR is a possible cause of infraduction deficit, being the complete isolated muscle avulsion more infrequent than longitudinal flaps. [5] We postulate that during orbital trauma, sudden traction by orbital septal attachments to the orbital layer of the rectus muscle (ref2) may tear the muscle. The resulting motility defect depends upon the severity of the torn inferior rectus as it scars into surrounding soft tissue. Prompt repair can restore function and anterior transposition of inferior oblique prevents secondary changes.

Prompt repair of snapped inferior rectus muscle with the help anterior transposition of inferior oblique is a safe and effective procedure to restore motility and a delay can give not good result.