BEUDAMED
    FDA Adverse Event Injury Summary report: N

    PLATE, FIXATION, BONE

    MDR report key: 3905462 · Received July 1, 2014

    Report

    Report Number
    2520274-2014-12253
    Event Type
    Injury
    Date Received
    July 1, 2014
    Report Date
    June 4, 2014
    Manufacturer
    SYNTHES (USA)
    Product Code
    HRS
    Adverse Event
    Yes
    Report Source
    Manufacturer report
    Reporter Location
    PA, US
    Reporter Occupation
    NURSE

    Narratives

    Additional Manufacturer Narrative · 1

    DEVICE WAS USED FOR TREATMENT NOT DIAGNOSIS. IF INFORMATION IS OBTAINED THAT WAS NOT AVAILABLE FOR THE INITIAL MEDWATCH, A FOLLOW-UP MEDWATCH WILL BE FILED AS APPROPRIATE. THIS REPORT IS FOR AN UNKNOWN TOMOFIX PLATE. THE INVESTIGATION COULD NOT BE COMPLETED AND NO CONCLUSION COULD BE DRAWN AS NO DEVICE WAS RETURNED AND NO LOT NUMBER OR PART NUMBER WAS PROVIDED.

    Description of Event or Problem · 1

    THIS REPORT IS BEING FILED AFTER THE SUBSEQUENT REVIEW OF THE FOLLOWING JOURNAL ARTICLE: DELAYED BONE HEALING FOLLOWING HIGH TIBIAL OSTEOTOMY RELATED TO INCREASED IMPLANT STIFFNESS IN LOCKED PLATING. ASYMMETRICAL CALLUS FORMATION AND INCOMPLETE BONE FORMATION UNDERNEATH STIFF LOCKING PLATES HAVE BEEN REPORTED RECENTLY IN CLINICAL AND EXPERIMENTAL FRACTURE HEALING STUDIES. AFTER SIMILAR EFFECTS WERE OBSERVED IN THE OUTCOME OF HIGH TIBIAL OSTEOTOMY (HTO) PATIENTS, A RETROSPECTIVE STUDY WAS PERFORMED TO QUANTIFY THE FREQUENCY AND LEVEL OF SUCH INCOMPLETE HEALING CASES. THE AUTHORS HYPOTHESIZE THAT LOCKING PLATES RESULT IN DELAYED BONE HEALING IN HIGH TIBIAL OSTEOTOMY (HTO) PATIENTS BECAUSE OF LOW INTERFRAGMENTARY MOVEMENTS (IFMS) AND TISSUE STRAIN UNDERNEATH A STIFF PLATE, AND THAT BY USING SCREWS WHICH ENABLE GREATER MOTION, THE IFM CLOSE TO THE PLATE CAN BE INCREASED. A RETROSPECTIVE REVIEW WAS PERFORMED FROM THE X-RAYS OF 74 CONSECUTIVE PATIENTS WHO UNDERWENT HTO FOR CONGENITAL OR POSTTRAUMATIC VARUS DEFORMITY BETWEEN 2003 AND 2012. ONLY PATIENTS WHO UNDERWENT ELECTIVE HARDWARE REMOVAL IN OUR CLINIC WITHOUT ANY COMPLICATIONS AND AFTER AN UNEVENTFUL COURSE WERE INCLUDED BECAUSE THIS ALLOWED SUFFICIENT EVALUATION OF X-RAYS WITH RESPECT TO CORTICAL DEFICIENCY UNDERNEATH THE PLATE. IN TOTAL, 23 PATIENTS (18 MALES, 5 FEMALES; MEDIAN AGE 44 YEARS, RANGE 20¿66 YEARS) WERE INCLUDED. THE RIGHT LEG WAS AFFECTED IN 12 PATIENTS AND THE LEFT IN 11 PATIENTS. HTO WAS PERFORMED USING THE MEDIAL OPEN WEDGE TECHNIQUE AS DESCRIBED. THE MEDIAN CORRECTION ANGLE WAS 8 DEGREES (5¿18 DEGREES). NO BONE GRAFTS WERE APPLIED TO FILL THE OSTEOTOMY GAP. THE OSTEOTOMY WAS STABILISED USING A LOCKING PLATE DESIGNED FOR HTO IN THE MEDIAL OPEN WEDGE TECHNIQUE (TOMOFIXTM, SYNTHES, (B)(4)). ELECTIVE HARDWARE REMOVAL FOLLOWING AN UNEVENTFUL CLINICAL COURSE WAS PERFORMED AFTER A MEDIAN TIME OF 19.5 MONTHS (12¿58 MONTHS) FOLLOWING THE OSTEOTOMY. ANTERIOR TO POSTERIOR X-RAYS OF THE AFFECTED KNEE WERE EVALUATED WHICH WERE OBTAINED AFTER A MEDIAN OF 21 MONTHS (13¿56 MONTHS) FOLLOWING THE HTO. THE AUTHORS PERFORMED AN IN VITRO BIOMECHANICAL EXPERIMENT USING THE SAME HTO ON A LOADED CADAVER KNEE JOINT TO COMPARE INTERFRAGMENTARY MOVEMENTS (IFMS) WHEN USING REGULAR LOCKING SCREWS WITH THE TOMOFIX PLATE AND SCREWS THAT ENABLED DYNAMIC STABILISATION OF THIS PLATE. THE BIOMECHANICAL EXPERIMENT DEMONSTRATED THAT VERY LOW IFMS AND CORRESPONDING INTERFRAGMENTARY STRAIN OCCUR UNDERNEATH THE PLATE WHEN USING REGULAR LOCKING SCREWS. REPLACEMENT WITH 5.0MM DYNAMIC LOCKING SCREWS (DYNAMIC LOCKING SCREWS, DLS, SYNTHES, (B)(4)) RESULTED IN AN INCREASED IFM. FIFTEEN PATIENTS (65%) DISPLAYED VARYING DEGREES OF INCOMPLETE CONSOLIDATION ACCORDING TO THE METHOD DESCRIBED. THE MEAN DEGREE OF UNHEALED OSTEOTOMY WAS 10.9% OF THE ORIGINAL LENGTH. ALL OF THE PATIENTS EVALUATED DISPLAYED CORTICAL DEFICIENCY. THERE WAS A TENDENCY FOR A LONGER TIME PERIOD TILL IMPLANT REMOVAL WAS PERFORMED IN THE GROUP WITH ASYMMETRIC CONSOLIDATION (27.2+/-11.3 MONTHS) COMPARED TO THE GROUP WHICH DISPLAYED GOOD HEALING AND COMPLETE FILLING OF THE CANCELLOUS BONE AREA IN THE FORMER OSTEOTOMY GAP (21.2 +/-9.6 MONTHS). A COPY OF THIS JOURNAL ARTICLE IS BEING SUBMITTED WITH THIS MEDWATCH. THIS IS 1 OF 2 REPORTS FOR COMPLAINT # (B)(4).

    Devices

    Seq Brand Generic Product Code Manufacturer Model Lot UDI-DI
    384992 PLATE, FIXATION, BONE HRS SYNTHES (USA)

    Patients

    Seq Age Sex Outcome Treatment
    1 Required Intervention