Modern ceramic-on-ceramic total hip systems in the United States: early results.

In 1997, two manufacturers began Food and Drug Administration approved investigations of a ceramic-on-ceramic (alumina) articulation total hip replacement in the United States. Osteonics (Allendale, NJ) and Wright Medical Technology (Arlington, TN) enrolled more than 500 and 300 patients, respectively, when their studies ended in the middle part of 1998. The author presents detailed early results of the series by Wright Medical Technology. Three hundred thirty-three patients were enrolled in 11 centers around the country in a prospective series. All patients received the Transcend ceramic-on-ceramic articulation and have a minimum of 18 months followup with a range of 18 to 36 months. Harris hip scores increased on average from 44 to 97 points. Four patients underwent revision surgery; one for deep infection, one for early migration of the cup, one for dislocation, and one for liner malplacement. Overall, there were 42 complications. Seven were systemic and 35 were related to the total hip replacement. Four of the 35 complications were ceramic related and included three chipped liners and one eccentric seating of the cup liner. To date, no patient underwent revision surgery for aseptic loosening. Seven technical guidelines are suggested to enhance the quality of the intraoperative and postoperative results: a conservative femoral neck cut; horizontal cup placement (< 45 degrees); increased anteverted cup placement (> 20 degrees); use of trial liners; impaction of ceramic pieces; hand placement of the liner; and removal of osteophytes and/or part of the anterior wall of the acetabulum to avoid impingement. Alternate bearing articulations, particularly ceramics, have important technical aspects to be considered at the time of implantation to minimize intraoperative and postoperative complications. To date, there have been no postoperative fractures of the ceramic pieces in any of the completed or ongoing ceramic-on-ceramic investigations by all involved manufacturers. These preliminary results are satisfactory at this time. One can look to the future with cautious optimism.