MAUDE Adverse Event Report: SMITH & NEPHEW ORTHOPAEDICS AG RT-PLUS MOD FEMORAL COMP. LEFT 4 CEM; PROSTHESIS, KNEE, FEMOROTIBIAL, CONSTRAINED, CEMENTED, METAL/POLYMER

Catalog Number 75005555

Device Problem Mechanical Problem (1384)

Patient Problems Injury (2348); Joint Disorder (2373)

Event Date 09/24/2018

Event Type  Injury  

Event Description

It was reported that the tibial component was loose and was removed.Subsequently, it was found that the hinge mechanism on the femoral component was extremely stiff.Therefore it was decided to change also the femoral component.

Manufacturer Narrative

Results of investigation: it was reported that the tibial component was loose and was removed.Subsequently, it was found that the hinge mechanism on the femoral component was extremely stiff and also removed.Only one rt-plus modular femoral component with the associated stem was returned for investigation.No batch numbers were communicated.No investigation can be performed on the tibial component.Destructive analysis performed on the femoral component.After removal of bone cement covering the explant, part number ¿24324¿ could be read.The batch number is partially readable and is assumed to be i1703147 after cross check with the production database.A dimensional evaluation was performed on the components of the disassembled hinge joint.However no conclusion could be reached on whether dimensional deviations contributed to the reported stiffness of the joint as the disassembly process as well as the sterilization after explantation have a significant influence on the geometry of pe elements.A review of the production documentation did not detect any deviation from the standard manufacturing processes.No other complaints have been recorded for this batch of femoral components.Based on the available medical information the root cause for the tibial ¿loosening¿ and the femoral ¿stiffening¿ cannot be concluded at this time.However the multiple interventions documented and ¿massively scarred¿ joint could be contributing factors in this issue.Despite the investigation performed no root cause for the reported issues could be determined.There is however to the best of our knowledge no indication that the reported device failed to match specification at the time of manufacturing.No further actions have been initiated.Should further information become available in the future this investigation will be reopened.(9613369-2018-00070: report related to tibial component).

Manufacturer Narrative

Updated results of investigation based on received x-rays: a revision surgery of a rt-plus knee system was reported due to loosening.The tibial component was first explanted.Subsequently, it was found that the hinge mechanism on the femoral component was extremely stiff and the femoral component was also removed.One rt-plus modular femoral component with the associated stem was returned for investigation.No batch numbers were communicated.The device was sterilized at the smith&nephew facility using a chemical process.This process is not expected to deform the pe components of the implant.Destructive analysis was performed on the femoral component.After removal of bone cement covering the explant, part number ¿24324¿ could be read.The batch number is partially readable and is assumed to be i1703147 after cross check with the production database.No signs of hyper-extension were observed neither on the metal components of the joint nor on the pe protector lining the femoral component.No abnormality were observed on the components of the hinge joint after disassembly, except from damage related to the disassembly itself.Due to the extensive amount of cement that was present around the implant and that was removed to allow the disassembly of the joint, no conclusive statement could be reached regarding the presence of residues inside the joint.No other complaints have been recorded for this batch of femoral components.A review of the production documentation for this batch did not detect any deviation from the standard manufacturing processes.The smoothness of the hinge joint is controlled on all implants at the end of the production process and no non-conformity were identified on this batch of implants.Furthermore, these is no indication in the submitted complaint that the joint was stiff at the time of implantation already.A dimensional evaluation was performed on the components of the hinge joint after disassembly.Dimensional deviation were observed on the pe elements of the hinge joint.Based on the performed investigation, these deformations took place either in-vivo or after explantation during the disassembly of the joint.There is no indication that the device failed to match specifications at the time of manufacturing.The available medical records, surgical reports and medical images provided were reviewed.Reported was a revision after approximately 1.5 years due to suspected tibial component loosening.During the revision the tibial component was confirmed to be loose and the femoral component was also found loose.Additionally, the hinge mechanism was found to be hard to move.Upon inspection, no signs of cement in the hinge could be found that might have caused the stiffening of the hinge mechanism.Additionally, a clear joint effusion and massive scarring was found.The ligament patellae needed to be mobilized, the tuberosity osteotomy was very sticky and insertion at the insertion was weakened.According to the implantation report, the patient had a pre-existing patella bacha, which was addressed by lowering the joint line.Removal of osteophytes and a smaller femoral part was used to increase flexion.At flexion of 80° there was a collision of the inferior pole of the patella.Due to preexisting scarring and thinning of the patellar ligament as well as a previous proximalisation this could not be further addressed.The provided x-rays of the device during the time in-vivo show a well-aligned implant.The provided ct did not allow to assess the inner part of the hinge-articulation.The reported findings do however not explain the stiffening of the hinge mechanism and the reason could not be determined.A possible interaction between the loosening and the stiff hinge mechanism cannot be further investigated.It cannot be excluded that the reported loosening of the tibial insert caused a deformation of the pe elements of the hinge joint, which in turn resulted in the stiffness of the joint.Based on the investigation performed the root cause of the reported issue cannot be determined conclusively.There is however to the best of our knowledge no indication that the reported component failed to match specification at the time of manufacturing.No further actions have been initiated following this complaint.(9613369-2018-00070: report related to tibial component).

• Brand Name: RT-PLUS MOD FEMORAL COMP. LEFT 4 CEM
• Type of Device: PROSTHESIS, KNEE, FEMOROTIBIAL, CONSTRAINED, CEMENTED, METAL/POLYMER
• Manufacturer (Section D): SMITH & NEPHEW ORTHOPAEDICS AG; oberneuhofstrasse 10d; baar, 06340 ; SZ 06340
• MDR Report Key: 7985263
• MDR Text Key: 124356749
• Report Number: 9613369-2018-00071
• Device Sequence Number: 1
• Product Code: KRO
• Combination Product (y/n): N
• PMA/PMN Number: K023667
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: company representative,health
• Type of Report: Initial,Followup,Followup
• Report Date: 09/03/2019

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 10/19/2018
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: No
• Device Operator: Health Professional
• Device Expiration Date: 02/28/2024
• Device Catalogue Number: 75005555
• Device Lot Number: I1703147
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 10/01/2018
• Date Manufacturer Received: 09/24/2018
• Is This a Reprocessed and Reused Single-Use Device?: No
• Patient Sequence Number: 1
• Treatment: 2 UNCEMNTED STEMS; INLAY GR.6 8MM; PATELLA GR.32/10MM; TIBIA GR.6, OFFSET 3.75MM,
• Patient Outcome(s): Hospitalization; Required Intervention
• Patient Age: 62 YR