MAUDE Adverse Event Report: BIOMET UK LTD. OXF ANAT BRG RT SM SIZE 4 PMA; UNICONDYLAR KNEE PROSTHESIS

Model Number N/A

Device Problems Mechanical Problem (1384); Device Dislodged or Dislocated (2923); Unintended Movement (3026)

Patient Problem Joint Dislocation (2374)

Event Date 12/04/2020

Event Type  Injury  

Manufacturer Narrative

(b)(4).Initial report: unique identifier (udi) number: (b)(4).Customer has indicated that the product has been discarded, therefore, it will not be returned to zimmer biomet for investigation.The investigation is in process.Once the investigation has been completed, a follow-up mdr will be submitted.

Event Description

It was reported that a patient underwent an initial right knee arthroplasty on (b)(6) 2020.Subsequently, a revision procedure due to dislocation was performed on (b)(6) 2020 when the bearing was revised to a different thickness.

Event Description

It was reported that a patient underwent an initial right knee arthroplasty on (b)(6) 2020.Subsequently, a revision procedure due to dislocation was performed on (b)(6) 2020 when the bearing was revised to a different thickness.

Manufacturer Narrative

(b)(4).As the product has not been received, the investigation was limited to the information provided; a review of device history records and complaint history.Radiographs received: four radiographs of an oxford partial right knee with were provided with (b)(4) for analysis.Email communication provided on etq informs that two radiographs were taken before revision on (b)(6) 2020, and the other two radiographs were taken after revision on (b)(6) 2020.Immediate post-primary radiographs are required to assess the initial size, fitting and positioning of components.The provided patient notes inform that radiographs were taken on (b)(6) 2020, (b)(6) 2020 and (b)(6) 2020.These have been requested but have not been received at the time of writing this assessment.The two pre-revision radiographs, one anteroposterior (ap) and one mediolateral (ml), show that the bearing had dislocated into the anterior joint space.This was noted in the provided x-ray report dated (b)(6) 2020, where it is stated that there appears to be metal-on-metal apposition of the components, and that the metallic markers of the tibial nylon meniscal component are anteriorly located relative to the medial femoral condyle.The x-ray markers of the bearing shown in the post-revision ap radiograph indicate that the meniscal bearing is articulating close to the medial edge of the tibial tray between the metal components.It is reasonable to assume that the position of the bearing post-revision is meaningful because it would be identical to prior revision, as both are dictated by the alignment of the metal components, which has not changed.The oxford partial knee surgical technique recommends the x-ray marker bar of the meniscal bearing to be central and parallel with the tibial component.In both provided ap radiographs, the femoral component appears to be positioned at a varus angle.The oxford partial knee surgical technique states that the varus angle of the femoral component should be lower than 10 degrees, as measured relative to the femoral axis.However, it is not possible to determine the exact extent of the component inclination in this instance due to quality of the provided images and because the radiographs do not show the full femur.The primary surgery notes mention that the intramedullary guide for the femur was then placed, the distal femoral condyle was marked along the central aspect of the axis.Both ap x-rays also show debris in the medial joint space, adjacent to the medial edge of the tibial tray.These could be fragments of bone or bone cement.The primary surgery notes state that cement was applied to the tibia, the tibial tray was then placed in the position impacted into position residual cement was resected using a woodson elevator.A post-operative x-ray report dated (b)(6) 2020 mentions that there is extruded methacrylate medial to the tibial plate.The original 4 mm bearing (discarded after surgery) was replaced by a 5 mm bearing, which suggests joint laxity may have been present.The primary surgery notes mention that trial femur and tibia were then trialed [sic] into position and brought in flexion which allowed for a 3/4 meniscal bearing trial, and extension this was brought to a 0 position, at which point 3 mm spigot was placed on the distal femur and additional 3 mm were then reamed.This allowed for a 3 4 and flexion, as well as a 3 4 and extension.At which point trials were then placed and taken anything range of motion which demonstrated excellent flexion and extension and stable varus and valgus stress testing.However, after cementing the tibial and femoral components, one size up from our previous implant was then placed into the meniscal space while bone cement cured.At the end of the surgery, the final bearing was taken through range of motion found to be excellently stable and symmetric in both flexion and extension and stability, no impingement anteriorly and no liftoff in deep flexion.However, it is possible that the use of a bearing trial thicker than the final trial produced some joint laxity.The operative report of the primary surgery states that the patient is male and was 72 years old.With a weight of 94.08 kg and a height of 190.5 cm, the patient had a bmi of 25.92 (overweight).The zimmer biomet product experience report (zper) states that the primary surgery was performed on (b)(6) 2020, the dislocation occurred on (b)(6) 2020, and the revision surgery was performed on (b)(6) 2020.The zper also mentions that bearing revision was performed per the surgical technique, and that there were no contributing conditions related to the bearing dislocation.However, the revision surgery notes mention that the patient used an inversion table for a work out and then started having swelling and grinding, and pain in the right knee.The instructions for use provided with the revised polyethylene bearing give the following warning: patients should be warned of the impact of excessive loading that can result if the patient is involved in an occupation that includes substantial walking, running, lifting, or excessive muscle loading due to weight that place extreme demands on the knee and can result in device failure or dislocation.It is not possible to determine the cause of the bearing dislocation without provision of further radiographic information and examination of the revised bearing.However it appears that joint laxity, suboptimal component positioning and excessive physical activity may have contributed to the adverse event in this instance.The manufacturing history record (mhr) for the oxford partial knee bearing has been checked and verifies that the component was manufactured and sterilised in accordance with the applicable specifications.A review of the complaint database over the last 3 years has found no similar complaints reported with the item and lot combination.A review of the complaint database over the last 3 years has found 1 similar complaint reported with the item 159569.Without the opportunity to examine the complaint product, root cause cannot be determined due to insufficient information, furthermore, the supplied photograph does not yield any information that could identify the cause.Risk assessment: risk management report documents the estimated residual risk associated with the device within the reported event.The root cause of the issue could not be determined with the information currently available, therefore the specific failure cause within the risk tables could not be selected for comparison.The reported event states revision due to bearing dislocation.In the risk file, dislocation is considered harm with a severity level of 3 for a number of hazards defined as moderate, which is described in the severity table as: s-3 prescribed medical or surgical intervention to preclude permanent impairment of a body function or body structure.Contributed to minor, temporary, or medically reversible injury.-the outcome of the reported event (surgical intervention) is considered to be within the severity of the rmf no corrective or preventive actions are deemed necessary at this time.If any additional information becomes available, then the complaint will be reopened and investigated thoroughly.

• Brand Name: OXF ANAT BRG RT SM SIZE 4 PMA
• Type of Device: UNICONDYLAR KNEE PROSTHESIS
• Manufacturer (Section D): BIOMET UK LTD.; waterton industrial estates; bridgend CF31 3XA; UK CF31 3XA
• MDR Report Key: 11026588
• MDR Text Key: 222013168
• Report Number: 3002806535-2020-00544
• Device Sequence Number: 1
• Product Code: NRA
• UDI-Device Identifier: 05019279786152
• UDI-Public: (01)05019279786152(17)240121(10)679680
• Combination Product (y/n): N
• PMA/PMN Number: P010014
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: company representative,health
• Type of Report: Initial,Followup
• Report Date: 01/13/2021

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 12/17/2020
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: No
• Device Operator: Health Professional
• Device Expiration Date: 01/21/2024
• Device Model Number: N/A
• Device Catalogue Number: 159569
• Device Lot Number: 679680
• Was Device Available for Evaluation?: No
• Was the Report Sent to FDA?: No
• Date Manufacturer Received: 01/13/2021
• Is This a Reprocessed and Reused Single-Use Device?: No
• Removal/Correction Number: N/A
• Patient Sequence Number: 1
• Patient Outcome(s): Hospitalization; Required Intervention
• Patient Age: 72 YR