MAUDE Adverse Event Report: STRYKER GMBH WASHER FOR SCREWS: Ø4.5/6.5/8.0MM; PLATE, FIXATION, BONE

Catalog Number	390016
Health Effect - Clinical Code	No Known Impact Or Consequence To Patient (2692)
Date of Event	05/03/2018
Type of Reportable Event	Malfunction
Additional Manufacturer Narrative
Once the investigation has been completed, any additional information will be reported in a supplemental report.
Event or Problem Description
When implanting a partial thread 6.5 cannulated screw in a si joint with a washer the head of the screw passed through washer prior to finished position.Then did it again on the other side.The washers were removed and the screws left in place.
Additional Manufacturer Narrative
The reported event that washer for screws: ø4.5/6.5/8.0mm was alleged of 'poor fixation' could not be confirmed, since the returned device is actually alleged of ' device deformed ' which could be confirmed instead.Based on investigation, the root cause was attributed to be user related.The failure was caused by inadequate applied force during screw insertion beyond its calculated capability.The device inspection revealed the following: both returned washers are indeed very badly deformed / damaged.Unfortunately we were not able to obtail the details of the screw and if there are some visible damages as both screws are still implanted.On the x-ray is evident that the screw got bent during insertion.Note that we have performed some tests in order to reproduce the screw slippage.Once with a softer and once with a harder artificial bone material.The softer material would not allow the washer to be bent at all.With the use of the harder material it was indeed possble to push the screwhead trough the washer with a tourque of 12.772 nm though which is beyond its calculated capability (see attached image documentation for details).The tests came to the result that, these characteristics clearly indicate that far too much mechanical force had been applied during screw insertion (overload beyond its calculated capability).Original statement from our medical expert: the x-ray shows the use of an 6.5mm cancellous screws which is rather unusual for this application.The screw naturally has very good hold in the mixture of cortical and cancellous bone and enormous tractive forces can be applied.Looking at the x-ray, where the screw and washer meets the bone, if i see it correctly, lies the spina iliaca anterior inferior with the sartorius muscle.There are also the lateral parts of the inguinal ligament are localized.These would be very solid non-radiopaque structures against which the washer can be pressed without it resting on the bone (could be an explanation that the screw head was able to be pushed through the washer).A review of the device history for the reported lot did not indicate any abnormalities.No corrective actions are required at this time.A review of the labeling did not indicate any abnormalities.No indications of material, manufacturing or design related problems were found during the investigation.If any further information is provided, the investigation report will be updated.
Event or Problem Description
When implanting a partial thread 6.5 cannulated screw in a si joint with a washer the head of the screw passed through washer prior to finished position.Then did it again on the other side.The washers were removed and the screws left in place.

• Brand Name: WASHER FOR SCREWS: Ø4.5/6.5/8.0MM
• Common Device Name: PLATE, FIXATION, BONE
• Manufacturer (Section D): STRYKER GMBH; bohnackerweg 1; postfach; selzach 2545 ; CH 2545
• MDR Report Key: 7558618
• Report Number: 0008031020-2018-00411
• Device Sequence Number: 2221946
• Product Code: HRS
• UDI-Device Identifier: 07613327095180
• UDI-Public: 07613327095180
• Combination Product (Y/N): N
• Initial Reporter State: NC
• Initial Reporter Country: US
• PMA/510(K) Number: K012162
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Reporter Type: Manufacturer
• Report Source: health professional
• Initial Reporter Occupation: Physician
• Type of Report: Initial,Followup
• Report Date (Section B): 08/31/2018

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Is this an Adverse Event Report?: No
• Is this a Product Problem Report?: Yes
• Operator of Device: Health Professional
• Device Catalogue Number: 390016
• Device Lot Number: L43917
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 07/23/2018
• Initial Date Received by Manufacturer: 05/03/2018
• Supplement Date Received by Manufacturer: 08/06/2018
• Initial Report FDA Received Date: 05/31/2018
• Supplement Report FDA Received Date: 08/31/2018
• Is This a Single-Use Device that was Reprocessed and Reused on a Patient? (Y/N): No
• Patient Sequence Number: 1
• Outcome Attributed to Adverse Event: Other
• Patient Age: 22 YR