Remark implantcast gmbh: please be aware of the difference between the terms dislocation and disconnection that were used by implantcast gmbh in this report.Dislocation: due to the design of the bi-polar head it is possible that the whole system (the bi-polar head and the femoral head) can dislocate out of the natural acetabulum as a whole.Disconnection: it is also possible that the individual components of this system disconnect, resulting in a separation of the ic-bipolar head and the femoral head.Since neither the product itself nor pictures of it were available no optical evaluation could be performed.However, the manufacturing protocols as well as the information material did not show any signs of failure or incompleteness, but the instructions for use lists a dislocation as possible adverse event.For the evaluation of the x-ray images, implantcast gmbh contacted a physician, who is experienced with this system.According to him there is an implantation error that may have caused the dislocation of the ic-bipolar head.The used combination does not induce enough joint tension which increases the risk of a dislocation.However, it is also worth noting that there is a noticeable clustering of incidents from (b)(6), as all incidents reported in recent time have happened there.Leading to the assumption that there also might be a korean related problem involved.With regard to their culture it is worth mentioning, that a main way of sitting is in a tailor seat, which needs a big range of motion of the hip joint.If an attempt is made to reach this range of motion too early after implantation along with a decreased joint tension due to implantation error, dislocation may occur as well.With only 2 weeks the implantation time is rather small.Therefore, regarding the case at hand it is possible, that the range of motion that was reached was too big for this implantation stadium.This assumption is also transferable to most of the other known cases with this error pattern.As to the disconnection, since it is known that in this case first a dislocation and afterwards a disconnection took place it is legitimate, to assume that the disconnection occurred due to a (presumable closed) reposition that failed.So, all in all it is safe to assume that at first the system dislocated and afterwards it got disconnected due to a failed repositioning.Furthermore, it is assumed that the dislocation occurs due to implantation error and / or due to (b)(6) specific problems.
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