Model Number N/A |
Device Problems
Material Integrity Problem (2978); Unintended Movement (3026)
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Patient Problems
Pain (1994); Loss of Range of Motion (2032); Metal Related Pathology (4530); Swelling/ Edema (4577)
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Event Date 04/04/2019 |
Event Type
Injury
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Manufacturer Narrative
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(b)(4).Initial report.Report source: foreign - event occurred in (b)(6).The product has not been returned to the manufacturer.Concomitant medical products: medical product: unk oxford femoral component, catalog #: unknown, lot #: unknown.Multiple mdr reports were filed for this event, please see associated reports: 3002806535-2021-00156.The investigation is in process.Once the investigation has been completed, a follow-up mdr will be submitted.
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Event Description
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Journal case report: fracture of femoral component in an oxford unicompartmental knee replacement with displaced posterior fragment.Authors: vb kiliyanpilakkil, s subramanian - the queen elizabeth hospital, king's lynn, uk the journal reported that the patient had an oxford unicondylar knee replacement 13 years ago.Following the procedure, he led a very active lifestyle.In recent months, however, he noticed intermittent pain, swelling and stiffness in his knee.He also had to swing his knee more than usual to mobilize.Additionally, the man had several episodes of knee locking which he had to manipulate to unlock.The patient attended the emergency department with acute painful locking of his knee.The man was getting out the car and his toe got caught inside the vehicle.His knee became twisted and got locked in flexion.The individual could not fully unlock his knee.Clinically, his knee was swollen and deformed.The patient had flexion deformity of 30° as well as varus deformity.His knee¿s range of motion was limited.Systemically, the patient was well with no clinical and laboratory features suggestive of infection.An x-ray of his knee showed femoral component fracture.The posterior fragment was rotated 180° and it was dislocated into the popliteal area.The mobile bearing insert had been displaced posteriorly along with a fractured femoral component, ultimately resulting in metal on metal articulation.The tibial component appeared well fixed and secure.The knee was aspirated to rule out infection.Following this, the man had a single stage revision arthroplasty.During the revision, the displaced posterior fragment was removed with some difficulty.The anterior part could be removed easily, while bone loss was very minimal on the femoral side.The tibial component was removed with slight bone loss.There was, however, evidence of metallosis and polyethylene wear in the knee.
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Manufacturer Narrative
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(b)(4).This final report is being submitted to relay additional information.Multiple mdr reports were filed for this event, please see associated report: 3002806535-2021-00156-1.No product was returned or pictures provided; visual and dimensional evaluations could not be performed.The oxford unicondylar knee system was revised following 13 years in situ.Part and lot identification are necessary for review of device history records, neither were provided.This device is used for treatment.No compatibility issues were noted.Complaint history review cannot be performed without product identification.The journal article provides pre revision x-rays showing the femoral component fracture.The posterior fragment was rotated 180 degree's and it was dislocated into the popliteal area.The mobile bearing insert had been displaced posteriorly along with a fractured femoral component, ultimately resulting in metal on metal articulation.The tibial component appeared well fixed and secure.The journal article believes that the reason for the failure was polywear and fatigue failure posterior to the peg due to metal on metal articulation.Thin posterior cement mantle may also have contributed.Reported event was unable to be confirmed due to limited information received from the customer.A definitive root cause cannot be determined.The patient had an uneventful recovery and his microbiology cultures were negative.At the patient¿s 6-month follow-up, his range of motion was 0-110 degrees and he had a stable, well-functioning knee replacement.No corrective actions, preventive actions, or field actions resulted after investigation of this event.If any additional information becomes available, then the complaint will be reopened and investigated thoroughly.
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Event Description
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The case report was taken from: journal article: fracture of femoral component in an oxford unicompartmental knee replacement with displaced posterior fragment.Author: vb kiliyanpilakkil, s subramanian the queen elizabeth hospital, king's lynn, uk.Revision due to implant fracture.The patient had an oxford unicondylar knee replacement 13 years ago.Following the procedure, he led a very active lifestyle.In recent months, however, he noticed intermittent pain, swelling and stiffness in his knee.He also had to swing his knee more than usual to mobilize.Additionally, the man had several episodes of knee locking which he had to manipulate to unlock.The patient attended the emergency department with acute painful locking of his knee.The man was getting out the car and his toe got caught inside the vehicle.His knee became twisted and got locked in flexion.The individual could not fully unlock his knee.Clinically, his knee was swollen and deformed.The patient had flexion deformity of 30 degrees as well as varus deformity.His knee¿s range of motion was limited.Systemically, the patient was well with no clinical and laboratory features suggestive of infection.An x-ray of his knee showed femoral component fracture.The posterior fragment was rotated 180 degrees and it was dislocated into the popliteal area.The mobile bearing insert had been displaced posteriorly along with a fractured femoral component, ultimately resulting in metal on metal articulation.The tibial component appeared well fixed and secure.The knee was aspirated to rule out infection.Following this, the man had a single stage revision arthroplasty.During the revision, the displaced posterior fragment was removed with some difficulty.The anterior part could be removed easily, while bone loss was very minimal on the femoral side.The tibial component was removed with slight bone loss.There was, however, evidence of metallosis and polyethylene wear in the knee.The study believes that the reason for failure was polywear and fatigue failure posterior to the peg due to metal on metal articulation.Thin posterior cement mantle may also have contributed.The patient had an uneventful recovery and his microbiology cultures were negative.At the man¿s 6-month follow-up, his range of motion was 0-110 degrees and he had a stable, well-functioning knee replacement.
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Search Alerts/Recalls
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