BEUDAMED
    FDA Adverse Event Injury Summary report: N

    APEX MODULAR HIP STEM

    MDR report key: 1053346 · Received May 28, 2008

    Report

    Report Number
    1226188-2008-00010
    Event Type
    Injury
    Date Received
    May 28, 2008
    Date of Event
    May 1, 2008
    Report Date
    May 27, 2008
    Manufacturer
    OMN LIFE SCIENCE, INC.
    Product Code
    KWY
    PMA / PMN Number
    K000788
    Adverse Event
    Yes
    Report Source
    Manufacturer report
    Reporter Location
    RI, US
    Reporter Occupation
    PHYSICIAN

    Narratives

    Additional Manufacturer Narrative · 1

    ADDITIONAL DEVICES USED: DEVICE: NECK +47.5; HEAD 28MM+3.5, CAT #: 220310, 302835; LOT# 339, 239. THERE WERE FIVE PIECES AVAILABLE FOR EXAMINATION: THE TITANIUM ALLOY FEMORAL STEM, THE TITANIUM ALLOY MODULAR NECK, THE COBALT CHROME BALL HEAD (ASSEMBLED ON THE NECK), THE TITANIUM ALLOY NECK PLUG, AND THE UHMWPE ACETABULAR CUP LINER (MANUFACTURER UNKNOWN). THE PROXIMAL END OF THE FEMORAL STEM SHOWED RETAINED BONE AT THE INGROWTH SURFACE AND MINOR SCRATCHES SECONDARY TO SURGICAL REMOVAL OF THE STEM. THE COBALT CHROME FEMORAL HEAD WAS FIRMLY SEATED ON THE MODULAR NECK, INTACT AND OTHERWISE UNREMARKABLE. THE NECK PLUG WAS INTACT AND OTHERWISE UNREMARKABLE. THE UHMWPE LINER HAD A HOLE THAT WAS MOST LIKELY CREATED TO FACILITATE REMOVAL OF THE LINER FROM THE SHELL, BUT WAS OTHERWISE INTACT AND UNREMARKABLE. THE COBALT CHROME ALIGNMENT PIN WAS FRACTURED, WITH THE DISTAL PORTION REMAINING IN THE FEMORAL STEM AND THE PROXIMAL PORTION REMAINING IN THE MODULAR NECK. THE FRACTURE SURFACES OF THE COBALT CHROME PIN HAD A MOTTLED APPEARANCE. THERE WERE NO INDICATIONS OF FATIGUE FRACTURE, SUCH AS ELONGATED RIDGES OR STRIATIONS. THE SUPERIOR SURFACE OF THE STEM AND INFERIOR SURFACE OF THE NECK WERE SCORED IN A CIRCULAR PATTERN, INDICATING ROTATION ABOUT THE LONGITUDINAL AXIS OF THE NECK PEG. BURNISHING OF THE NECK PEG WERE THE PEG ENGAGED THE STEM AND GOUGING OF THE STEM ADJACENT TO THE HOLE, INTO WHICH THE PIN WAS PRESS-FIT, WERE ALSO CONSISTENT WITH ROTATION OF THE NECK ON THE STEM. IN SUMMARY, THESE FINDINGS SUGGEST THAT FAILURE OCCURRED DUE TO SHEAR FRACTURE OF THE ALIGNMENT PIN, FOLLOWED BY ROTATION OF THE NECK ON TOP OF THE STEM WITH SUBSEQUENT SCORING AND SURFACE ABRASION AS DESCRIBED. DIMENSIONAL INSPECTION OF THE MODULAR STEM AND NECK INTERFACES WERE PRECLUDED BY ABRASIVE WEAR SECONDARY TO FAILURE OF THE ALIGNMENT PIN AND MODULAR NECK. REVIEW OF THE INSPECTION RECORDS FOR THE SPECIFIC STEM AND NECK LOTS INDICATES THAT THE DIMENSIONS OF THE MODULAR NECK PEG AND MATING HOLE IN THE STEM WERE WITHIN SPECIFICATION. ACCORDING TO A MEMO ATTACHED TO THE ROUTER FOR THE FEMORAL STEM LOT (DATED 2002), THE COBALT CHROME ALIGNMENT PIN MAY HAVE BEEN SLIGHTLY UNDERSIZED (0.0006" OR LESS); TO PROVIDE ADEQUATE RETENTION STRENGTH OF THE PINS IN THE FEMORAL STEMS, THE DISTAL END OF THE PINS WERE DEFORMED PRIOR TO PRESS-FITTING THE PINS INTO THE FEMORAL STEMS. THE CERTIFICATE OF COMPLIANCE AND CHEMICAL COMPOSITION FOR THE COBALT CHROME ALIGNMENT PIN INDICATES CONFORMANCE TO ASTM F1537, INCLUDING YIELD STRENGTH (124 KSI), TENSILE STRENGTH (179 KSI), AND ELONGATION (21%).

    Description of Event or Problem · 1

    FAILED STEM, TOTAL HIP REVISION IN 2008, 52 MONTHS AFTER ORIGINAL SURGERY.

    Devices

    Seq Brand Generic Product Code Manufacturer Model Lot UDI-DI
    1 APEX MODULAR HIP STEM POROUS FEMORAL STEM KWY OMN LIFE SCIENCE, INC. 121455 268

    Patients

    Seq Age Sex Outcome Treatment
    1 68 YR Required Intervention