title: Complications of pegged and non-pegged hydroxyapatite orbital implants.
abstract: OBJECTIVE
  The purpose of this study is twofold: to assess the incidence and implications of complications unique to placing a freestanding polycarbonate peg in patients with hydroxyapatite implants and to compare the incidence of complications in these patients with the incidence in patients with non-pegged hydroxyapatite implants.
  
  
  METHODS
  This is a retrospective clinical case series of 103 patients who underwent hydroxyapatite implant insertion at our institution. The incidence of postoperative complications in patients who underwent freestanding polycarbonate pegging procedures (n = 21) and those who had not (n = 82) were compared.
  
  
  RESULTS
  One postoperative complication - infection - occurred in a significantly higher percentage of patients in the pegged group (42.9%, 9/21) compared with the non-pegged group (19.5%, 16/82), (p = 0.037). Fifteen of the 21 patients (71.4%) in the pegged group experienced complications unique to freestanding polycarbonate pegging. Overall, 95.2% (20/21) of patients in the pegged group experienced a complication compared with 58.5% (48/82) of patients in the non-pegged group, (p = 0.001). In addition, there was an average of 3.1 (66/21) complications per patient in the pegged group compared with an average of 1.9 (106/82) complications per patient in the non-pegged group (p = 0.010).
  
  
  CONCLUSIONS
  Patients who received a freestanding polycarbonate pegged implant had a high risk of experiencing complications unique to pegging, and therefore a significantly higher rate of complications overall when compared with patients whose implant was not pegged. In addition, patients who received a pegged implant had a higher incidence of infection. However, most patients retained their pegs despite complications.
authors.affiliation: W.K. Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, University of Michigan Health System, Ann Arbor, MI, USA.
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Fahim
authors.forename: Bartley R
authors.initials: BR
authors.lastname: Frueh
authors.forename: David C
authors.initials: DC
authors.lastname: Musch
authors.forename: Christine C
authors.initials: CC
authors.lastname: Nelson
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001672:Biocompatible Materials; D002648:Child; D002675:Child, Preschool; D017886:Durapatite; D015353:Eye Enucleation; D005137:Eye, Artificial; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020273:Orbital Implants / Q000009:adverse effects*; D011076:Polycarboxylate Cement / Q000009:adverse effects*; D011183:Postoperative Complications; D012189:Retrospective Studies; D053831:Surgical Fixation Devices / Q000009:adverse effects*
chemical_list: D001672:Biocompatible Materials; D011076:Polycarboxylate Cement; C005506:polycarbonate; D017886:Durapatite