MAUDE Adverse Event Report: STANMORE IMPLANTS WORLDWIDE JTS DRIVE UNIT SET; PROSTHESIS, KNEE, FEMOROTIBIAL, CONSTRAINED, CEMENTED, METAL/POLYMER

Catalog Number JTS-DRIVE-UNIT

Device Problem Failure to Advance (2524)

Patient Problem Unequal Limb Length (4534)

Event Date 04/01/2021

Event Type  malfunction  

Manufacturer Narrative

Please note that this event is related to a jts drive unit which is used in conjunction with the jts non-invasive extendible implant (k092138).Should additional information become available, it will be provided in a supplemental report upon completion of the investigation.Device not returned.

Event Description

As reported by rep: "the surgeon attempted to lengthen this patient who has a jts proximal femur non-invasive implant and the implant shortened.He put me on video and verified the correct set up of the patient.The magnet (mle) and console that he was using on (b)(6) 2021 is the same one that he used in (b)(6) successfully lengthening this same patient.The magnet was located in his office and had not moved since then.I am sending various x-rays.Since the implant was shortening on the correct setting, i instructed him to try to lengthen on and verify with x-ray.This also shortened the implant.Resulting in a total of 15mm shortening in one day when usually we lengthening 4mm.I have also sent the email from the surgeon confirming this information.The magnet will be brought in for review and inspection.I have requested the medical records of these patient visits." as reported by surgeon: "we ended up taking 1.5 cm out of patient today unfortunately ¿ 5 mm on a and 1 cm on b after we reversed it and tried to make up for the loss.The family said they are willing to come back as soon as we have a magnet available." as reported in clinic note: "we reviewed an x-ray prior to leaving the office which showed that he had 5 mm of shortening rather than 5 mm of lengthening.We discussed this with the implant manufacture and we did not come up with a clear explanation for this.We tried reversing the magnet and after 8 minutes it appeared to have lengthened 2 mm so we continued another 32 minutes of what we thought was lengthening.We then checked a final x-ray which showed further shortening.".

Manufacturer Narrative

Reported event: an event regarding a non functional jts, drive unit was reported.The event was not confirmed.Method & results: device evaluation and results: visual inspection: not performed as item was returned due to annual maintenance, during maintenance no visual discrepancies identified.Dimensional inspection: not performed as not relevant for the failure mode reported.Functional inspection: review of the annual maintenance and functional inspection indicates the device conformed to requirements.Material analysis: not performed as not relevant for the failure mode reported.Clinician review: performed for the associated jts distal femoral replacement - implant.Device history review: review of the annual maintenance indicates the device conformed to requirements.Complaint history review: there have been no other events for the serial number referenced.Conclusion: an event regarding seizing involving a jts, drive unit, was reported.The rep reported that the "on (b)(6) 2021 the surgeon attempted to lengthen this patient who has a jts proximal femur non-invasive implant and the implant shortened.He put me on video and verified the correct set up of the patient [.] since the implant was shortening on the correct setting (a), i instructed him to try to lengthen on (b) and verify with x-ray.This also shortened the implant.Resulting in a total of 15mm shortening in one day".Update 07 april 2021: after the unsuccessful lengthening on (b)(6) 2021, the jts drive unit (b)(6) successfully passed the annual maintenance on 07 april 2021.Update (b)(6) 2021: on the (b)(6) 2021 the sales rep reported that the implant was successfully extended 10mm with an unknown jts drive unit, thus the implant remained in situ.The sales rep concluded the previous unsuccessful lengthening may be as of a result of "anomaly or surgeon error".The exact cause of the event could not be determined because insufficient information was provided.Additional information including progress notes is needed to fully investigate the event.If further information becomes available of the product are returned, this investigation will be re-opened.

Event Description

As reported by rep: "the surgeon attempted to lengthen this patient who has a jts proximal femur non-invasive implant and the implant shortened.He put me on video and verified the correct set up of the patient.The magnet (mle) and console that he was using on (b)(6) 2021 is the same one that he used in february successfully lengthening this same patient.The magnet was located in his office and had not moved since then.I am sending various x-rays.Since the implant was shortening on the correct setting (a), i instructed him to try to lengthen on (b) and verify with x-ray.This also shortened the implant.Resulting in a total of 15mm shortening in one day when usually we lengthening 4mm.I have also sent the email from the surgeon confirming this information.The magnet will be brought in for review and inspection.I have requested the medical records of these patient visits." as reported by surgeon: "we ended up taking 1.5 cm out of patient today unfortunately ¿ 5 mm on a and 1 cm on b after we reversed it and tried to make up for the loss.The family said they are willing to come back as soon as we have a magnet available." as reported in clinic note: "we reviewed an x-ray prior to leaving the office which showed that he had 5 mm of shortening rather than 5 mm of lengthening.We discussed this with the implant manufacture and we did not come up with a clear explanation for this.We tried reversing the magnet and after 8 minutes it appeared to have lengthened 2 mm so we continued another 32 minutes of what we thought was lengthening.We then checked a final x-ray which showed further shortening.".

• Brand Name: JTS DRIVE UNIT SET
• Type of Device: PROSTHESIS, KNEE, FEMOROTIBIAL, CONSTRAINED, CEMENTED, METAL/POLYMER
• Manufacturer (Section D): STANMORE IMPLANTS WORLDWIDE; 210 centennial avenue; centennial park, elstree; borehamwood WD6 3 SJ; UK WD6 3SJ
• MDR Report Key: 11715375
• MDR Text Key: 254010940
• Report Number: 3004105610-2021-00066
• Device Sequence Number: 1
• Product Code: KRO
• Combination Product (y/n): N
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: health professional
• Type of Report: Initial,Followup
• Report Date: 09/21/2021

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 04/23/2021
• Is this an Adverse Event Report?: No
• Is this a Product Problem Report?: Yes
• Device Operator: Health Professional
• Device Catalogue Number: JTS-DRIVE-UNIT
• Device Lot Number: 907-027
• Was Device Available for Evaluation?: Device Returned to Manufacturer
• Date Returned to Manufacturer: 04/07/2021
• Date Manufacturer Received: 08/26/2021
• Is This a Reprocessed and Reused Single-Use Device?: No
• Patient Sequence Number: 1
• Patient Outcome(s): Other
• Patient Age: 9 YR