The incidence of blow out fractures is increasing and the techniques of diagnosis and treatment have been recently evolving. Despite its clinical significance, there has been no study on orbital inferiomedial blow out fractures. Therefore, this study was designed to investigate the clinical significance of treatment of orbital inferiomedial blow out fractures.

A retrospective review of fifty-seven patients who could be followed up for at least 1 year after surgical reconstruction of pure inferiomedial blow out fracture was undertaken. The transconjunctival approach was performed in all cases. The onlay technique was used in 32 patients and the inlay/sheet method was used in 25 patients. We evaluated the clinical outcomes using the chi-square test.

In the group using the onlay technique, postoperative diplopia and enophthalmos were observed in 14 cases and 3 cases, respectively. Of these, 5 cases and 3 cases lasted for more than 6 months, respectively. In the group using the inlay/sheet method, postoperative diplopia was observed in 9 cases, but there were no cases of enophthalmos. Among the 9 diplopia cases, 4 lasted for more than 6 months.

Postoperative diplopia and enophthalmos were increased after treatment of inferiomedial blow out fractures compared to isolated medial (0.6%, 0.3%) or inferior (1.8%, 0.6%) blow out fractures. Therefore, careful dissection is necessary not to injure the inferior oblique muscle to decrease the incidence of postoperative diplopia. Moreover, the inlay/sheet method is an effective option for reconstruction of inferiomedial blow out fractures.