There was a mismatch between the prepared bone and the trial.Cuts were assessed with the planar probe and even after paying close attention to run over the cuts multiple times, some cuts were deep by over 1 mm (distal) and others were proud (anterior chamfer).The surgeon very closely visually assessed the cuts and noticed that the medial anterior chamfer was elevated compared to the lateral side.After manually rasping that side down the trial fit snuggly and the cuts seemed more aligned.Case type / application: tka update: additional information: when checking the cuts with the planar probe they were over a mm deep without showing those results with the green/white/red visual aid during bone prep.There also seemed to be an uneven cuts that was causing a mismatch between the prepared bone and trial.Update: "the 2 cuts that he checked with the planar probe were the distal and anterior champfer.The distal cut was showing about 1.2mm deep (the bone prep page did not show red on the cut).The anterior champfer was about 1mm proud.When he rocked the femur trial, if he was flush on the medial side he was lifted up about 3mm on the lateral side and vise versa if he was flush on the lateral side.".
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Reported event an event regarding inaccurate resection involving a mako tka software was reported.The event was not confirmed because the product was not available for inspection.Method & results product evaluation and results: based on the analysis of the relevant log files and session file: the accuracy of the robotic arm is not confirmed as the user failed to lower the rio for rio (robot) registration, which can cause vibratory motion in the base array leading to inaccurate rio registration transform compromising the cutters location with respect to the bone.The arm accuracy can also be compromised by rough handling of the arm and pushing through the stereotactic there was a torque limit error in joint 2 prior to the distal resection step.The velocity trap values for the base array during the distal and anterior chamfer cut were 4 to 5 times the limit of 40 mm/s.The base array is expected to remain stationary during the cutting event.These high base array velocity trap values may be indicative of a loose fisso-articulated arm or base array connection, something pulling or pushing on the base array, and or vibration transmission form the surgical table or surroundings to the base array or camera.The passing checkpoint between the distal and anterior resection indicate that vibratory motion was elastic, meaning the arrays returned to their original position following the vibratory event.However, if the array is moved even elastically during the cutting event inaccurate cuts can issue.The checkpoints both tool and cutter were not checked following the anterior chamfer resection, which does not rule out a base array motion during the anterior chamfer resection.Clinician review: no medical records were received for review with a clinical consultant.Product history review: review of the device history records indicate devices were manufactured and accepted into final stock with no relevant reported discrepancies.Complaint history review: there are other complaints with a similar failure mode for this lot.Conclusions: based on the analysis of the relevant log files and session file: the rio system was performing within its specifications there is no indication of system malfunction.Probe check passed as well as rio registration, pre-surgery checks, bone registration, and bone checkpoints.The accuracy of the robotic arm is not confirmed as the user failed to lower the rio for rio (robot) registration, which can cause vibratory motion in the base array leading to inaccurate rio registration transform compromising the cutters location with respect to the bone.The arm accuracy can also be compromised by rough handling of the arm and pushing through the stereotactic there was a torque limit error in joint 2 prior to the distal resection step.The velocity trap values for the base array during the distal and anterior chamfer cut were 4 to 5 times the limit of 40 mm/s.No additional investigation or specific actions are required.If additional information is received, then the complaint will be reopened.H3 other text : not available.
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There was a mismatch between the prepared bone and the trial.Cuts were assessed with the planar probe and even after paying close attention to run over the cuts multiple times, some cuts were deep by over 1 mm (distal) and others were proud (anterior chamfer).The surgeon very closely visually assessed the cuts and noticed that the medial anterior chamfer was elevated compared to the lateral side.After manually rasping that side down the trial fit snuggly and the cuts seemed more aligned.Case type / application: tka.Update: additional information: when checking the cuts with the planar probe they were over a mm deep without showing those results with the green/white/red visual aid during bone prep.There also seemed to be an uneven cuts that was causing a mismatch between the prepared bone and trial.Update: "the 2 cuts that he checked with the planar probe were the distal and anterior chamfer.The distal cut was showing about 1.2mm deep (the bone prep page did not show red on the cut).The anterior champfer was about 1mm proud.When he rocked the femur trial, if he was flush on the medial side he was lifted up about 3mm on the lateral side and vise versa if he was flush on the lateral side.".
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