Batch review performed on (b)(6) 2019: lot 150741: (b)(4) items manufactured and released on 03-mar-2015.Expiration date: 2020-01-31.No anomalies found related to the problem.To date, (b)(4) items of the same lot have been already sold without any similar reported event.Clinical evaluation performed by medical affairs director: very difficult knee revision case, in a valgus knee in an obese patient.The alignment on the frontal plane is very challenging and the surgeon used a complex construct with offset stem, but even so the valgus alignment partially remains.The patient's tibia is severely bowed in the frontal plane, a very anomalous condition, mechanically challenging.In these conditions the prosthesis is subject to extreme loads and a component failure may happen.In this case, we see a probably loose insert fixation screw, but in the last radiograph also the metal post seems to have dislocated.The report does not describe this situation.The main cause for revision should be the dislocated post, but the information supplied is not sufficient to perform a complete analysis of the event.The conditions described in the instructions for use of the device as conditions that may compromise the duration and the success of the operation are massively present in this case.However, we acknowledge that a viable alternative to preserve the patient's limb may not be easy to be implemented.Visual inspection performed by r&d knee manager: revision surgery after 2 year and a half from primary surgery for breakage of the gmk hinge tibia insert secure screw and loosening of the broken part into the knee joint.The hinge insert secure screw is broken in 2 pieces in correspondence to the threaded shaft at the level of the interface between the tibia tray and the insert, where the flexion moment acting on the screw is maximum.This broken part was found loosened in the joint.We suppose that the remaining part of the screw remained seated in the tibia tray.It is not possible to find an explanation for the screw breakage.We can only suppose that unpredictable loads acting on the insert caused the breakage of the secure screw.This overloading is most likely linked to a progressive worsening of the clinical condition of the patient and increased instability resulting in increased loads acting on the implant.This remain only a supposition and can't be proved.
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