By event description, no mechanical failure of the prosthesis (metal back and glenosphere were well fixed one each other when came loose from glenoid bone).This has been confirmed by a radiologic evaluation and by some photos of the explants returned.Explants not returned.No anomalies detected by checking the dhr of the metal back and glenosphere involved.No other complaints received on these lot # (metal back: (b)(4) pieces manufactured; glenosphere: (b)(4) pieces manufactured).Additional findings by x-rays evaluation: in the x-ray dated (b)(6) 2015 (immediate post-op), whole construct of mb + glenosphere appears to be already partially out of the glenoid bone (in the superior part); this suggests a suboptimal implant technique.The x-ray dated (b)(6) 2015 shows that the whole construct completely came out from the bone.Probable cause of the incident: suboptimal implantation technique, maybe combined with inadequate bone support to sustain the loads of the system mb + glenosphere.As reported by smr surgical technique: "the bone stock of the glenoid and humerus must be able to support the implant.In cases with significant bone loss and in which adequate fixation on the glenoid side cannot be obtained, a hemi with cta head should be performed." pms data: revision rate associated to this event is 0.034%; the majority of similar events was due to improper implantation or patient trauma / bone condition.No corrective actions.(b)(4) corporate will keep the market monitored to promptly detect possible recurrence of such event.Device not returned.
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