Prediction of the development of late enophthalmos in pure blowout fractures: delayed orbital tissue atrophy plays a major role

Purpose: To retrospectively evaluate the risk factors for the development of late enophthalmos in pure blowout fractures. Methods: We reviewed 49 cases of pure blowout fractures diagnosed in Ajou University Hospital, South Korea, from January 2005 to June 2015. We assumed that several factors influence the development of late enophthalmos, including bony defect size, volume of displaced soft tissue, number of fracture sites, involvement of floor, soft tissue incarceration through the bony defect, and patient age. Results: Twenty-one patients were diagnosed with late enophthalmos (group 1) while 28 patients were not (group 2). Soft tissue incarceration, presumably causing the soft tissue injury, was the only factor that increased the risk for late enophthalmos in this study (p = 0.04, odds ratio 4.5). In contrast with previous studies, there were no meaningful correlation between bony defect size or volume of displaced soft tissue and development of late enophthalmos. Number of fracture sites, involvement of floor, and patient age did not increase the risk for late enophthalmos. Conclusions: We suggest that the delayed orbital tissue atrophy due to soft tissue injury plays a more important role than other hypotheses in the development of late enophthalmos. It is necessary to overcorrect to some extent if there is soft tissue incarceration through the bony defect in the initial computed tomography, and clinicians should warn patients about the development of late enophthalmos despite orbital reconstructive surgery.