title: Late porous polyethylene implant exposure after motility coupling post placement.
abstract: OBJECTIVE
  To report the probable association of motility coupling post placement and late porous polyethylene implant exposure.
  
  
  METHODS
  Retrospective, observational case series.
  
  
  METHODS
  This was a retrospective analysis of 27 patients who had primary porous polyethylene orbital implantation from February 1999 to November 2000. Data on demographics, previous surgery, ocular diagnosis, type of surgery, size of the implant, and motility coupling post placement were collected. Complications of porous polyethylene implants and implant exposure were documented.
  
  
  RESULTS
  Among the 27 patients, 18 eyes (66.7%) received motility coupling post insertion after primary porous polyethylene implantation. Implant exposure occurred in six (33.3%) of the 18 eyes with motility coupling post insertion. None of the eyes without insertion had implant exposure. The mean interval between porous polyethylene implantation and motility coupling post placement for the implant exposure group (6 of 18) was 6.5 +/- 0.4 months, which was not statistically significant compared with 7.2 +/- 0.6 months in the nonexposure group (12 of 18). For these 6 cases of implant exposure, the mean interval between implantation and implant exposure was 24.2 +/- 11.8 months, and the mean interval between pegging and exposure was 17.6 +/- 11.7 months. Among these 6 patients, 4 underwent removal of exposed porous polyethylene implants and reimplantation of hydroxyapatite implant or dermis fat reconstruction.
  
  
  CONCLUSIONS
  We found a trend (P =.07) of increasing risk of porous polyethylene implant exposure with motility coupling post placement. Although the pegging group did not show a statistically significant higher rate of exposure compared with the nonpegging group, we believe that more care was needed when performing motility coupling post placement. In addition, longer postoperative follow-up is needed after insertion of a motility coupling post.
authors.affiliation: Department of Ophthalmology, National Taiwan University Hospital, 7 Chung Shan South Road, Taipei, Taiwan.
authors.forename: Man Sim
authors.initials: MS
authors.lastname: Cheng
authors.forename: Shu Lang
authors.initials: SL
authors.lastname: Liao
authors.forename: Luke L-K
authors.initials: LL
authors.lastname: Lin
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D020878:Device Removal; D015353:Eye Enucleation; D017234:Eye Evisceration; D005133:Eye Movements; D005260:Female; D005548:Foreign-Body Migration / Q000175:diagnosis / Q000209:etiology* / Q000601:surgery; D005549:Foreign-Body Reaction / Q000175:diagnosis / Q000209:etiology* / Q000601:surgery; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D020273:Orbital Implants / Q000009:adverse effects*; D020959:Polyethylene; D016062:Porosity; D019919:Prosthesis Implantation / Q000009:adverse effects*; D012086:Reoperation; D012189:Retrospective Studies; D012307:Risk Factors
chemical_list: D020959:Polyethylene