MAUDE Adverse Event Report: MEDACTA INTERNATIONAL SA GMK SPHERE TOTAL KNEE SYSTEM; GMK-SPHERE TIBIAL INSERT - FLEX S4L - 10 MM

Model Number	02.12.0410FL
Medical Device Problem Code	Migration (4003)
Health Effect - Clinical Code	Implant Pain (4561)
Date of Event	05/06/2026
Type of Reportable Event	Serious Injury
Additional Manufacturer Narrative
Clinical evaluation approximately 10 years after primary total knee arthroplasty, the insert fixation screw was found loose within the joint.This finding is supported by the available radiographic images.According to the complaint report, the patient presented with knee pain following a fall; therefore, the traumatic event may have acted as a contributing or triggering factor.However, based on the available information, the fall alone appears insufficient to be considered the definitive root cause of the screw back-out.The screw loosening may have developed progressively over time, potentially related to mechanical factors such as insufficient initial tightening torque, repetitive micro-motion, patient-related loading conditions, or other unknown factors.Spontaneous screw back-out has been reported previously and has commonly been associated with insufficient tightening torque administered at the time of index surgery.Since the introduction of the torque-limiting screwdriver, the number of observations, which was already below (b)(4) of cases, has nearly disappeared.Nevertheless, screw back-out after such a long time in situ is very rare.Moreover, the actual timing of onset cannot be determined, as it is unknown whether the screw loosened acutely after the reported fall or progressively before the patient became symptomatic.Based on the available information, no definitive root cause can be established.The event should be considered potentially multifactorial, with trauma as a possible contributing or revealing factor rather than a confirmed primary cause.Batch review performed on 22 may 2026: lot.154366: (b)(4) items manufactured and released on 22-dec-2015.Expiration date: 2020-dec-05.No anomalies found related to the problem.To date, (b)(4) items of the same lot have been sold with no similar reported event during the period of review.Root cause:based on the information available, no definitive root cause can be established.The screw loosening may have developed progressively over time, potentially due to insufficient initial tightening torque, repetitive micro-motion, patient-related loading conditions, or other unknown factors.The reported fall may have contributed to the clinical manifestation; however, no confirmed device-related root cause can be identified based on the available information.
Event or Problem Description
Revision surgery was performed due to screw loosening in the surgically repaired knee, which was observed following a fall approximately 9 years and 9 months after the primary surgery.The surgeon removed the screw and revised the flex left 10mm s4 insert to a flex 4l - 12mm insert at his discretion.The surgery was completed successfully.

• Brand Name: GMK SPHERE TOTAL KNEE SYSTEM
• Common Device Name: GMK-SPHERE TIBIAL INSERT - FLEX S4L - 10 MM
• Manufacturer (Section D): MEDACTA INTERNATIONAL SA; strada regina; castel san pietro 6874 ; SZ 6874
• Manufacturer Contact: marco giannessi ; strada regina; castel san pietro 6874 ; SZ 6874
• MDR Report Key: 25328465
• Report Number: 3005180920-2026-00512
• Device Sequence Number: 9805859
• Product Code: JWH
• UDI-Device Identifier: 07630030826535
• UDI-Public: 07630030826535
• Combination Product (Y/N): N
• PMA/510(K) Number: K121416
• Number of Events Summarized: 1
• Summary Report (Y/N): N
• Device Implanted Year: 2016
• Device Explanted Year: 2026
• Serviced by Third Party (Y/N): N
• Reporter Type: Manufacturer
• Report Source: Company Representative
• Initial Reporter Occupation: Other
• Type of Report: Initial
• Report Date (Section B): 05/29/2026

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: No
• Operator of Device: Health Professional
• Device Expiration Date: 05/12/2020
• Device Model Number: 02.12.0410FL
• Device Lot Number: 154366
• Was Device Available for Evaluation?: No
• Type of Report(Section G): Thirty-Day
• Initial Date Received by Manufacturer: 05/06/2026
• Initial Report FDA Received Date: 05/29/2026
• Was Device Evaluated by Manufacturer? (Y/N): Device Not Returned to Manufacturer
• Date Device Manufactured: 12/22/2015
• Is the Device Labeled for Single Use? (Y/N): Yes
• Is This a Single-Use Device that was Reprocessed and Reused on a Patient? (Y/N): No
• Usage of Device: Initial
• Patient Sequence Number: 1
• Outcome Attributed to Adverse Event: Required Intervention
• Patient Age: 73 YR
• Patient Sex: Female
• Patient Weight: 118 KG
• Patient Race: White