MAUDE Adverse Event Report: SMITH & NEPHEW ORTHOPAEDICS AG RT-PLUS MOD TIBIAL COMPONENT 2 CEM; PROSTHESIS, KNEE, FEMOROTIBIAL, CONSTRAINED, CEMENTED, METAL/POLYMER

Catalog Number 75005559

Device Problem Loose or Intermittent Connection (1371)

Patient Problem Injury (2348)

Event Date 08/06/2018

Event Type  Injury  

Event Description

A revision surgery was reported due to a breakage of the central pivot of the tibial baseplate.

Manufacturer Narrative

A revision surgery was reported due to the loosening of a rt-plus modular tibial component.The reported explant was returned for evaluation.The metal clamp is fractured.The inferior aspect of the insert has broken off.Macroscopic fracture striation are visible on the fracture surface.The orientation of these striations indicate a slow propagation of the fracture from posterior to anterior direction.Abrasion marks are observed on the articulating surface of the insert.A review of the production documentation did not detect any deviation from the standard manufacturing processes.No similar complaint was reported for this batch of products.The available medical documents were reviewed.The provided implantation report indicates the one-stage surgery was performed due to septic loosening following multiple previous surgeries.The loose femoral and tibial component were revised and replaced.According to the provided revision report, the patient showed a dislocation of the implant in association of a lateral tilt of the patella.During the revision, hemarthrosis, adhesions, inflammatory synovia and a fractured pivot of the inlay were noted.The patella shows fibrosis and fractures that was treated with ligamentoplasty, screws and sutures.The provided results from microbiological testing of different samples from the surgery showed no growth of germs, except in one sample.Without x-rays the position and the size of the chosen implant with respect to the patient anatomy can however not be evaluated.Whether this issue with the patella contributed to the reported issue cannot be further assessed.Based on the available information, the root cause of the reported issue remains undetermined.There is however to the best of our knowledge no indication that the device failed to meet specifications at the time of manufacturing.No further actions have been initiated.If additional information becomes available in the future this investigation will be reopened.

Manufacturer Narrative

X-rays documents arrived and were assessed: final results: a revision surgery was reported due to a breakage of the central pivot of a rt-plus modular pe insert.A fractured tibial insert and fragments of the metal clamp were returned for investigation.A review of the production documentation did not detect any deviation from the standard manufacturing processes.No similar complaint was reported for this batch of products.The returned explant was analysed.The metal clamp is fractured.The inferior aspect of the insert has broken off.Macroscopic fracture striation are visible on the fracture surface.The orientation of these striations indicate the propagation of a fatigue crack from posterior to anterior direction prior the final fracture of the insert.Furthermore abrasion marks are observed on the articulating surface of the insert.It was reported that 4 days before the revision and after an indirect choc of the knee during a false move the patient could not walk due to pain.The provided medical report and corresponding x-rays from this date show that the peg of the hinge mechanics is aligned towards posterior and close to complete dislocation, the clamp fixing the inlay is attached to the inlay, which is dislocated and the stem of the tibial component is aligned towards posterior within the medullary canal.According to the provided revision report, the patient showed a dislocation of the implant in association of a lateral tilt of the patella.Whether these issues reported in the medical documents such as lateral tilt of the patella or the adhesions, the small size of the implant, the 14 mm thick inlay or other factors contributed to the reported fracture and dislocation cannot be further investigated.Based on the available information, no specific root cause for the reported fracture could be determined.There is however to the best of our knowledge no indication that the device failed to meet specifications at the time of manufacturing.Smith&nephew will continue to monitor this device for similar issues.

• Brand Name: RT-PLUS MOD TIBIAL COMPONENT 2 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: 7887954
• MDR Text Key: 120694178
• Report Number: 9613369-2018-00059
• 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,foreig
• Type of Report: Initial,Followup,Followup
• Report Date: 01/14/2019

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 09/18/2018
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: No
• Device Operator: Lay User/Patient
• Device Catalogue Number: 75005559
• Device Lot Number: H1713509
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 10/01/2018
• Is This a Reprocessed and Reused Single-Use Device?: No
• Patient Sequence Number: 1
• Patient Outcome(s): Hospitalization; Required Intervention