Abstract
Introduction
One of the major concerns in the use of modular hip prostheses is the structural failure of one or more components of the prosthesis, with total mechanical failure. In literature there are sporadic cases of breakage of the prosthetic neck in patients with high functional demand.
Material and methods
In our experience we have implanted a model of modular hip prostheses in 38 patients. In 17 of these patients it was implanted a neck made of titanium alloy, while in the remaining 21 was utilised a CrCo neck. In 5 of the 17 patients with neck titanium it has been a spontaneous rupture of the neck in a time ranging from 12 to 24 months. We proceeded with the replacement of the titanium neck with similar neck made of CrCo alloy in 5 patients with failed neck, and we decided to call the remaining 12 patients with titanium neck, offering them the revision of the system. All patients accepted the revision surgery.
Results
implants explanted and subject to breakage of the neck were analyzed by an independent metallurgical laboratory which has produced a document in which were found the main signs of wear which led to the deterioration of metal involved.
Conclusions
The rupture of the modular hip prostheses is a possible event both because of the high functional loads required by some types of patients, that of the building materials and design of the modular components. In this study we are presented the results of the laboratory tests that allow us to pose hypotheses about the causes and failure mechanisms of modular hip prostheses.
