MAUDE Adverse Event Report: AESCULAP AG AS FEMUR EXTENS.STEM 6° D12X157 CEMENTED; KNEE ENDOPROSTHESES

Model Number NR294Z

Device Problem Break (1069)

Patient Problem No Code Available (3191)

Event Date 12/05/2018

Event Type  Injury  

Manufacturer Narrative

(b)(4).Manufacturing site evaluation: pictures were provided.When we receive the explanted devices, we will make an investigation in consultation with specialists from the development and marketing department.Investigation - no product at hand.This case was discussed with a specialist from the marketing department.Batch history review - a review of the device quality and manufacturing history records was not possible because the lot numbers are unknown.Conclusion (broken stem)- it is not possible to determine a definitive root cause of the broken stem.It could be possible that this failure is usage/patient related.Rationale (broken stem) - product was not returned for investigation, so it is not possible to determine a root cause for the mentioned failure.It is mentioned that the patient had several revision operations with several implants.Therefore it can be assumed that the bone was prepared several times- little bone substance or possible bone defects of the patient.This led to the femur component not being supported enough and therefore the loading being transmitted through the femur box to the femur stem and the nut.If the load is too high, the component will break.Investigation on-going.Additional information / investigation results will be provided in a supplemental report.

Event Description

It was reported that an enduro femoral stem broke and the patient underwent a revision.Prior to implantation of the enduro femoral stem, it was noted that the patient had previously undergone several total knee arthroplasties.The operation on (b)(6) 2013 and implantation of the enduro knee system had been a revision of a hinge prosthetic and the patient also required bone graft for condyles at that time.Over 5 years later, the patient was found to have a broken femoral stem, which was shown via x-rays in (b)(6) 2018.The revision occurred on (b)(6) 2018, and the plan had been to remove and replace the femoral stem only.When the locking nut of the femoral component was attempted to be loosened, there was difficulty and it was not immediately successful.After some more efforts were made, the damaged locking nut was ejected as part of the femoral piece.The surgery was then continued as originally planned by removing the femoral stem, which was also difficult.Reconstruction of the femur was performed with use of small metaphyseal 35 and diaphyseal 30.There was implantation of the same size femoral component along with a stem and addition of 2-8x8 spacers.A new meniscal component with new axis was implanted; finally, the new femoral component was tightened.It was felt that perhaps the months of stress on the femoral component (from (b)(6) to (b)(6)) due to the broken femoral stem resulted in jamming of the nut.It was reported that there had been a surgical delay of greater than 15 minutes due to the difficulty in loosening the original nut.It was later noted that the threads on the tension screw (holder/impactor) were damaged/broken.This report addresses the revision and broken femoral stem.Associated medwatches: 9610612-2018-00599 ; 9610612-2018-00600 (this report); 9610612-2018-00619.

Manufacturer Narrative

Associated reports: 9610612-2018-00599, 9610612-2018-00619.Investigation: the available components were examined visually and microscopically with a keyence vhx-5000 digital microscope and a panasonic dmc tz8 digital camera.This case was discussed with a specialist from the marketing and development department.The tension screw is broken at the thread.The broken piece is still fixed in the femur extension nut.The breakage surface of both pieces (proximal part and distal part) exhibit no material defects like foreign particles, inclusions, or blow holes.The locking nut is seriously damaged.We assume that this happened during the explanation procedure with the mentioned tungsten tool, because a loosening of the locking nut was not possible.The femur component was implanted with wedges on both sides to correct the bone defects of the patient.Especially on the medial side of the femur component, the bone defects were compensated with large quantities of bone cement.There are clearly visible imprints on the top of the femur box as well as on the corresponding under side of the extension stem.The bearing for rotation axis is divided into two pieces, probably during the explanation process.The meniscal component shows visible scratches on the gliding surface.We assume that this results from bone cement residues which get between the gliding surface and the femoral component.Batch history review: a review of the device quality and manufacturing history records was not possible because the lot numbers are unknown.Conclusion and root cause: based on the information available as well as a result of our investigation, the root cause of the failure is probably patient/usage related.

Event Description

Consultation on (b)(6)2018 where the patient presented with complaints of right knee pain since june 2016.She felt at that moment a brutal function deterioration with a senstion of cracking.She has debilitating pain that forces her to move with the aide of two canes.Her knee is imbedded; the articual amplitudes are limited in flexion.The radiographic assessments shows a rupture of the prosthetic extension keel.Revision surgery was scheduled for (b)(6)2018.

• Brand Name: AS FEMUR EXTENS.STEM 6° D12X157 CEMENTED
• Type of Device: KNEE ENDOPROSTHESES
• Manufacturer (Section D): AESCULAP AG; po box 40; tuttlingen, 78501 ; GM 78501
• MDR Report Key: 8200199
• MDR Text Key: 131527810
• Report Number: 9610612-2018-00600
• Device Sequence Number: 1
• Product Code: KRO
• Combination Product (y/n): N
• PMA/PMN Number: K101815
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: company representative,foreig
• Type of Report: Initial,Followup
• Report Date: 01/14/2019

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 12/27/2018
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: Yes
• Device Operator: Health Professional
• Device Model Number: NR294Z
• Device Catalogue Number: NR294Z
• Was Device Available for Evaluation?: Yes
• Distributor Facility Aware Date: 01/07/2019
• Date Manufacturer Received: 01/07/2019
• Is This a Reprocessed and Reused Single-Use Device?: No
• Patient Sequence Number: 1
• Treatment: REF: (B)(4), FEMORAL SPACER; REF: (B)(4), MENISCAL COMPONENT; REF: (B)(4), NUT F/FEMUR EXTENS. STEM; REF: (B)(4), TIBIA OFFSET STEM; REF: (B)(4), TIBIAL COMPONENT; REF: NB012Z, TIBIAL COMPONENT; REF: NR195Z, TIBIA OFFSET STEM; REF: NR377Z, FEMORAL SPACER; REF: NR400Z, NUT F/FEMUR EXTENS. STEM; REF: NR883Z, MENISCAL COMPONENT
• Patient Outcome(s): Required Intervention
• Patient Age: 81 YR