AMISTEM H FEMORAL STEMS

Additional Manufacturer Narrative

BATCH REVIEW PERFORMED ON 02 JUN 2026 LOT 151454: (B)(4) ITEMS MANUFACTURED AND RELEASED ON 21-SEP-2015. EXPIRATION DATE: 08-SEP-2020. NO ANOMALIES FOUND RELATED TO THE PROBLEM. TO DATE, ALL THE ITEMS OF THE SAME LOT HAVE BEEN SOLD WITH ONE SIMILAR REPORTED EVENT DURING THE PERIOD OF REVIEW. CLINICAL EVALUATION PERFORMED BY CLINICAL AFFAIRS MANAGER AT 10 YEARS AFTER PRIMARY CEMENTLESS THA, THE STEM GETS LOOSE AND NEEDS REPLACEMENT. THE PATIENT IS LARGE, WITH VERY LONG FEMORAL NECKS; THE SHORT STEM, IMPLANTED IN A SLIGHTLY VARUS POSITION, PROBABLY DID NOT FIND A GOOD PROXIMAL FIT AND FAILED TO PROPERLY TRANSFER LOADS TO THE PROXIMAL PART OF THE FEMUR, RESULTING EVENTUALLY IN DISTAL FIXATION AND LOSS OF PROXIMAL PRESS FIT. AFTER 10 YEARS, THIS CASE SHOULD PROBABLY BE CATEGORIZED AS IDIOPATHIC ASEPTIC LOOSENING. INVESTIGATION PERFORMED BY R&D PROJECT MANAGER FROM THE IMAGE RECEIVED THE EXPLANTED STEM IS VISIBLE AND COVERED WITH PATIENT BLOOD AND ATTACHED TO THE FEMORAL HEAD. ON THE STEM BODY NO HA RESIDUALS ARE VISIBLE, MEANING THAT METABOLIC ACTIVITY WAS TAKING PLACE AND THAT, PRESUMABLY, ADEQUATE BONE CONTACT WAS ACHIEVED AT THE TIME OF SURGERY. SOME SIGNS OF MINOR DAMAGE AND SCRATCHES ARE PRESENT ON THE NECK OF THE EXPLANTED STEM, WHICH IS LIKELY DUE TO THE REVISION SURGERY AND NOT RELEVANT TO THE REPORTED ISSUE. BASED ON THE ANALYSIS COMPLETED AND INFORMATION AVAILABLE, IT IS NOT POSSIBLE TO IDENTIFY A ROOT CAUSE OF THE STEM LOOSENING REPORTED. ROOT CAUSE:ASEPTIC LOOSENING IS POSSIBLE LITERATURE DESCRIBED ADVERSE EVENT AFTER PRIMARY JOINT ARTHROPLASTIES AND CAUSES ARE OFTEN UNKNOWN. THERE IS NO INDICATION THAT ANY POTENTIAL ISSUE WITH THE DEVICE MAY HAVE CAUSED OR CONTRIBUTED TO THE EVENT AND THE INVESTIGATION DOES NOT INDICATE ANY POTENTIAL MANUFACTURING RELATED ISSUE OR SYSTEMIC DEFICIENCY.

Description of Event or Problem

REVISION SURGERY PERFORMED DUE TO STEM LOOSENING 10 YEARS AFTER PRIMARY. A POSTERIOR APPROACH WAS USED FOR REMOVAL OF THE STEM AND HEAD. A SIZE 5 MINIMAX STEM AND AN XL 36 MM CERAMIC HEAD WERE IMPLANTED.