SILICONE-RUBBER TEMPOROMANDIBULAR-JOINT (TMJ) MENISCAL REPLACEMENTS - POSTIMPLANT HISTOPATHOLOGIC AND MATERIAL EVALUATION

Medical grade silicone rubber has long been considerd a suitable meniscal replacement, but there has been increasing concern about migration of this material into adjacent tissues. The objectives of this study were to determine the definitive composition of tissue-incorporated material which is presumed by light microscopy to be silicone and to identify long term histopathologic sequelae of meniscal replacement. Adult female patients underwent meniscectomy and replacement with silicone rubber (Silastic) implants. After 12 to 18 months, recurrence of symptoms in 8% of these cases led to implant removal with excision of peri-implant fibrous pseudocapsules. Excised tissues, including one preauricular lymph node and implants were submitted for light microscopy, SEM, and energy dispersive X-ray microanalysis (EDX) for the identification of elemental composition, critical surface tension measurement, and internal reflection infrared spectroscopy. EDX revealed prominent peaks for silicon in both pseudocapsular and nodal tissues. Morphologicl findings surrounding the long-term implants included foreign body reaction synovitis, dystrophic calcification, fibrocartilaginous metaplasia, hyalinization, and scarring.