MAUDE Adverse Event Report: STRYKER GMBH LOCKING SCREW, T10, 3.5X14MM; PLATE, FIXATION, BONE

Catalog Number 40-35614S

Device Problem Mechanics Altered (2984)

Patient Problems No Known Impact Or Consequence To Patient (2692); No Information (3190)

Event Date 05/09/2018

Event Type  malfunction  

Manufacturer Narrative

Once the investigation has been completed any additional information will be reported in a supplemental report.

Event Description

During variax fibula surgery, the locking screw did not lock in the most distal hole.The screw was once removed, removal and cleaning of soft tissue was performed, but the issue was not resolved.The surgeon exchanged the screw with another same size screw, but the screw could not be locked.Therefore, re-drilling was performed using drill sleeve but the issue was not resolved.Ultimately, the surgery was finished with the screw unlocked and lag screw fixation was added using 3.5 mm non-locking screw in order to increase fracture stability.

Event Description

During variax fibula surgery, the locking screw did not lock in the most distal hole.The screw was once removed, removal and cleaning of soft tissue was performed, but the issue was not resolved.The surgeon exchanged the screw with another same size screw, but the screw could not be locked.Therefore, re-drilling was performed using drill sleeve but the issue was not resolved.Ultimately, the surgery was finished with the screw unlocked and lag screw fixation was added using 3.5mm non-locking screw in order to increase fracture stability.

Manufacturer Narrative

The reported event that locking screw, t10, 3.5x14mm was alleged of issue (no locking effect) could be confirmed since the device was returned for evaluation and matches the alleged failure mode.The threads on the screw head (locking threads) are heavily deformed/damaged.Such damage is most likely caused due to misalignment between the trajectory of the screw and the drilled hole trajectory leading to multiple attempts of locking.Also, the damage of the locking thread can be due to improper use of instruments.A review of the device history for the reported lot did not indicate any abnormalities.No corrective actions are required at this time.No indications of material, manufacturing or design related problems were found during the investigation.Based on investigation, the root cause was attributed to a user related issue.Such failure can occur in case of improper use of the instruments or drilling of holes at an angle greater than 15° as indicated in operative technique.Misalignment between the trajectory of the screw and the drilled hole trajectory leading to multiple attempts of locking.This damaged the locking threads on screw head making it impossible to lock.The op-techs explains the instrumentation usage as intended.It provides details preparation for screw insertion and screw insertion such as drilling, measuring, screw selection and screw insertion.It clearly states that a drill guide must first be placed into a corresponding plate screw hole (in a plate), prior to pre-drilling a pilot hole.The drill guide is designed to limit drilling to a ±15° angle with respect to the plate.Drilling at an angle greater then ±15° may prevent locking from taking place, and is not recommended.Misinterpretation of color coding logic can also be one cause of improper instrumentation.The op-techs explain the variax instrumentation usage in general incl.The color coding system and pictures of laser engraved symbols and words.Laser marking on instruments show instrument dimension & compatibility.Excessive plate bending may also lead to failure of the locking mechanism, and is not re-commended.A review of the labeling did not indicate any abnormalities.The instructions for use states that ¿responsibility for proper selection of patients, adequate training of the surgeon, the choice and placement of implants, post-operative treatment, and the decision to leave or remove implants postoperatively, rests with the surgeon.¿ if any further information is provided, the investigation report will be updated.

• Brand Name: LOCKING SCREW, T10, 3.5X14MM
• Type of Device: PLATE, FIXATION, BONE
• Manufacturer (Section D): STRYKER GMBH; bohnackerweg 1; postfach; selzach 2545 ; CH 2545
• MDR Report Key: 7567054
• MDR Text Key: 110197240
• Report Number: 0008031020-2018-00413
• Device Sequence Number: 1
• Product Code: HRS
• UDI-Device Identifier: 04546540539410
• UDI-Public: 04546540539410
• Combination Product (y/n): N
• PMA/PMN Number: K063875
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: health professional
• Type of Report: Initial,Followup
• Report Date: 11/15/2018

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 06/04/2018
• Is this an Adverse Event Report?: No
• Is this a Product Problem Report?: Yes
• Device Operator: Health Professional
• Device Expiration Date: 01/16/2023
• Device Catalogue Number: 40-35614S
• Device Lot Number: 1000286379
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 07/04/2018
• Date Manufacturer Received: 10/23/2018
• Is This a Reprocessed and Reused Single-Use Device?: No
• Patient Sequence Number: 1
• Patient Outcome(s): Other