MAUDE Adverse Event Report: STRYKER GMBH UNKNOWN UNKNOWN STAR MOBILE BEARING; PROSTHESIS, ANKLE, UNCEMENTED, NON-CONSTRAINED

Catalog Number UNK_SEL

Device Problems Fracture (1260); Appropriate Term/Code Not Available (3191)

Patient Problem Pain (1994)

Event Date 08/05/2019

Event Type  Injury  

Manufacturer Narrative

Upon completion of investigation, additional information will be provided in a supplemental report.

Event Description

Patient has increasing pain in ankle.As per an exam note on (b)(6) 2019: "looking at his x rays, i think his metal components are probably okay.It looks like he has significant asymmetry of his poly, and i bet his poly is fractured.It's my impression that he has broken or spit out his poly status post right ankle joint replacement.".Revision surgery occurred as a result.

Event Description

Patient has increasing pain in ankle.As per an exam note on april 16, 2019: "looking at his x rays, i think his metal components are probably okay.It looks like he has significant asymmetry of his poly, and i bet his poly is fractured.It's my impression that he has broken or spit out his poly status post right ankle joint replacement.".Revision surgery occurred as a result.

Manufacturer Narrative

The reported event could be confirmed.Based on investigation, the root cause was attributed to be user related.The device inspection revealed the following: the component is fractured in three parts.A large zone of the sliding core is highly deformed, most probably due to an unbalanced repartition of the mechanical forces on the implant during the 7 years of implantation.This discrepancy in mechanical loading could be one of the reasons the material broke due to fatigue "faster." the ankle joint with a star implant is a complex mechanism of motion and is dependent upon proper alignment.A misalignment to this ankle joint complex system affects the interactions between metal and poly and causes degradation of the poly and visual wear on the metal.As a conclusion, according to our medical expert, no obvious clinical or surgical root cause can be noticed from the documents provided.However, patient related factors could explain the accelerated fatigue and wear of the device.Indeed, even a slight inadequate repartition of mechanical forces could have affected the devices lifespan.The ifu guide instructs the users that: " [.] appropriate selection, placement and fixation of the star ankle components are critical factors which affect implant service life.[.]" as well as: "[.] potential adverse effects of the device on health reported device related adverse effects.The most commonly reported adverse effects associated with the star ankle are the following: [.] mobile bearing fracture." a review of the device history was not possible because the lot number was not communicated, and the returned suspect device was extensively deformed that the catalog and lot code was illegible.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.

• Brand Name: UNKNOWN UNKNOWN STAR MOBILE BEARING
• Type of Device: PROSTHESIS, ANKLE, UNCEMENTED, NON-CONSTRAINED
• Manufacturer (Section D): STRYKER GMBH; bohnackerweg 1; postfach; selzach 2545 ; CH 2545
• MDR Report Key: 8938317
• MDR Text Key: 159518732
• Report Number: 0008031020-2019-01174
• Device Sequence Number: 1
• Product Code: NTG
• Combination Product (y/n): N
• PMA/PMN Number: P050050
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: other
• Type of Report: Initial,Followup
• Report Date: 11/08/2019

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 08/27/2019
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: Yes
• Device Operator: Lay User/Patient
• Device Catalogue Number: UNK_SEL
• Device Lot Number: UNKNOWN
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 08/08/2019
• Date Manufacturer Received: 10/14/2019
• Is This a Reprocessed and Reused Single-Use Device?: No
• Patient Sequence Number: 1
• Patient Outcome(s): Required Intervention
• Patient Age: 76 YR
• Patient Weight: 79