MAUDE Adverse Event Report: AESCULAP AG METHA NECK 12/14 135°/7.5°L ANTE-R RETRO; HIP ENDOPROSTHETICS

Model Number NC087K

Device Problem Material Fragmentation (1261)

Patient Problem Device Embedded In Tissue or Plaque (3165)

Event Date 10/17/2018

Event Type  Injury  

Manufacturer Narrative

(b)(4).Manufacturing site evaluation: the three parts were received from the hospital and sent for decontamination.A further investigation will take place once the items complete the decontamination process.In general, due to the limited information available it is not possible to fully evaluate this case to date.After the prosthetics are available, the case investigation will be further executed.

Event Description

It was reported by the healthcare professional to the company sales representative "initial suspicion of a loosening of the hofer-cup left side after ct examination".A female patient had hip implant surgery on (b)(6) 2008.During that procedure, the following sterile parts were implanted: metha neck 12/14, 135 degree/7.5 degree left ante-r retro; metha short hip stem cap size 2, and biolox prosthetic head 12/14 36 mm m.Additionally, another manufacturer's products were implanted: hofer shell 6-11, hofer cup size 6/plus orthopedics, and ceramic insert 44/36 mm/plus orthopedics.Postoperatively, on an unknown date, there was suspicion that the hofer cup had loosened following review of ct exam results.A revision was scheduled.On (b)(6) 2018, revision surgery was performed.During the operation, metal particles were observed in the tissues and abrasive synovialitis.Cultures were taken and samples of soft tissue were sent for examination; results were negative for infection or malignancy.The metha neck, short hip stem cap, and head were removed.It was not confirmed whether the hofer components were also extracted and replaced.Further details and patient outcome has not yet been provided.Additional information is expected.All medwatch submissions related to this patient are: 9610612-2018-00507 (this report), 9610612-2018-00508, 9610612-2018-00509.

Manufacturer Narrative

Associated reports: 9610612-2018-00508, 9610612-2018-00509.Investigation: the investigation was carried-out by the r&d department.In order to demonstrate the wear patterns on the cone surface, a macroscopical investigation of the cone was performed.The cone surface shows wear patterns in the medial and lateral contact areas due to dynamic and corrosive stress after approximately 11 years in vivo.Due to the introduction of force and the biochemical load vector, the medial and lateral cone sides represent the main contact surfaces.On the medial cone surface, the damage is concentrated on a linear contact area through which the high bending moment is introduced into the prosthesis stem.Afterwards the medial contact surfaces were investigated with the rem (scanning electron microscope) and the edx (energy dispersive x-ray spectroscopy) for damages due to corrosive effects and fretting.Damage to the cone surface as a result of a combination of fretting and corrosion as well as electrolytic metal dissolution primarily in the contact areas of the cone surface could be detected.The limited repassivation of the surface and the characteristic wear patterns allow the conclusion that the mechanical wear was increased due to metal dissolution under aggressive environmental conditions.Furthermore, partial titanium transfer coming from the shaft component to the cone adapter could be found.Additionally, a tactile measuring of the cone surface was excuted to determine the wear volume with a coordinate measuring machine.Batch history review: a lot number was not provided, therefore a review of the device history records must remain incomplete.Furthermore there is no approval for a destructive testing, therefore it is not possible to read the laser marking on the cone adapter due to the fact that the ceramic ball head is still positioned at the cone adapter.Conclusion and root cause: the macroscopial investigation of the metha neck shows that due to dynamic corrosive stress the cone surface exhibits wear patterns.The further investigation of the medial contact areas with the rem and edx analyses demonstrates that the cone surface was damaged as consequence of a combination of fretting and corrosive effects.The limited repassivation of the surface and the characteristic wear patterns indicate that due to metal dissolution on aggressive surrounding conditions the mechanical abrasion was massively strengthened.Rationale: after the investigation of the components we could not detect a manufacturing failure or a material defect.Therefore it is possible that a wear induced reaction associated with a patient related higher sensitivity and an aggressive environmental conditions led to the corrosion.Furthermore, non-aesculap components (metal shell, ceramic insert) were combined with aesculap components (metal stem, neck adapter and ceramic ball head).Such a combination is neither allowed nor approved by aesculap.We do not know how this system combination performs.It is possible that the mix & match situation may have led to a higher friction between ceramic ball head and ceramic insert.This phenomena can also lead to higher forces within the neck-adapter/stem connection (micro movements).No capa is necessary.

• Brand Name: METHA NECK 12/14 135°/7.5°L ANTE-R RETRO
• Type of Device: HIP ENDOPROSTHETICS
• Manufacturer (Section D): AESCULAP AG; po box 40; tuttlingen, 78501 ; GM 78501
• MDR Report Key: 8070892
• MDR Text Key: 127204326
• Report Number: 9610612-2018-00507
• Device Sequence Number: 1
• Product Code: LWJ
• Combination Product (y/n): N
• PMA/PMN Number: K071916
• 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: 01/28/2019

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: Yes
• Device Operator: Health Professional
• Device Model Number: NC087K
• Device Catalogue Number: NC087K
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 11/09/2018
• Distributor Facility Aware Date: 01/22/2019
• Initial Date Manufacturer Received: 10/19/2018
• Initial Date FDA Received: 11/14/2018
• Supplement Dates Manufacturer Received: 01/22/2019
• Supplement Dates FDA Received: 01/29/2019
• Is This a Reprocessed and Reused Single-Use Device?: No
• Patient Sequence Number: 1
• Treatment: 1 - REF: 0030794 SHELL; 1 -REF: 0030786 H023 HOFER CUP; 1 -REF: 66021-A KE38 CERAMIC INSERT
• Patient Outcome(s): Required Intervention
• Patient Age: 79 YR