Difficulties with hydroxyapatite orbital implants in two patients with dysfunctional levator/superior rectus muscle complex.

Hydroxyapatite orbital implants are recognized for their excellent results in anophthalmos. Few complications are reported in the literature. We implanted hydroxyapatite spheres in two patients with acquired anophthalmos and denervated or nonfunctional levator palpebrae superioris and superior rectus muscles. In both patients, the implant rotated anteriorly, obliterating the superior fornix and causing proptosis. Prosthetic fitting was impeded, necessitating surgical revision in both patients. A hydroxyapatite implant may rotate and migrate anteriorly in the presence of a nonfunctional superior rectus muscle, distorting the conjunctival fornices and causing proptosis. This complication calls into question whether muscle-attached orbital implants should be used in patients with significant rectus muscle weakness.