Investigation: this case was discussed with a sme from the r&d department.The stem shows bony adhesion of erratic appearance on the plasmapore coating.Scratches can be found on the outer surface of the metal stem.Shape and geometry leads to the assumption that the scratches originated most likely during the revision surgery.Furthermore metal transfer can be found on the ceramic ball head as well as on the ceramic insert.On the x-ray pictures it can be seen that a part of the anterior femur bone gradually dissolves up to the lesser trochanter.Batch history review: the device quality and manufacturing history records have been checked for all available lot numbers.The device history file has been checked and found to be according to our specification valid at the time of production.No similar incidents have been filed with products from this batch.Conclusion and root cause: based on the information available and as a result of our investigation, a product related failure can be excluded.Material or product deviations could not be identified.The failure is most probably user or patient related.Rational: no material or manufacturing errors can be found.The scratches on the outer surface of the stem did not provide any information about the cause of the discomfort or a potential loosening and originated most likely during the revision surgery.The bone residues on the metal stem indicate that the stem was implanted properly and that a adhesion took place.Furthermore a loosening of the stem cannot be clearly confirmed on the basis of the x-ray pictures.However, the pictures indicate that the anterior femur bone gradually dissolved after the primary surgery.This could have led to the discomfort.The metal transfer on the taper of the insert might indicate a partial rotation of the insert in the metal shell in a seated position.As a result of this rotation, it is possible that the small metal particles got into the bearing and caused the conspicuous metal abrasion on the inner surface of the insert and the outer surface of the ball head.However, it can not be decided clearly whether this metal transfer occured in-situ or during the revision surgery.The metal transfer on the outer surface of the ceramic insert as well as on the front face of the ceramic ball head, was probably produced during the revision surgery.Based on the investigation, a product related failure can be excluded.No capa is necessary.
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