Medical product.Allofit 50/hh, item#4244, lot#2784456.Durasul insert hh/32, item# 01.00013.408, lot# 2801293.Müller-geradschaft standard, 10; item#12.00.29-100, lot# 2789748.Therapy date: (b)(6) 2020.Event description: it was reported that there was suspicion of wear at the head-stem taper interface with osteolysis without indication for infection.Review of received data: due diligence: no further due diligence required as all required information to support the conclusion is available or was already requested.Emails from surgeon: received on 06 mar 2020 except for the information already filled in on the first page of this report, the email states the following information: indication for implantation: medial femoral neck fracture (type garden iii) anamnesis, previous surgeries, affected joint: on (b)(6) 2015 the patient presented in the emergency room with pain in the area of the left hip as a result of a fall.The leg was shortened and externally rotated; there was no restriction of peripheral blood circulation, motor function or sensitivity at any time.Pre-existing complaints in the area of the left hip are not known.All components were removed and replaced by a revision prosthesis: brehm curved stem size 15x200 mm, tm cup size 52 mm, biolox delta head size 36 m.Received on 09 sep 2020.The email states the following information: x-rays and ct showed pronounced lysis and a gradual migration of the cup.The ct showed metal particles, so that metal wear in the sense of a loosening had to be assumed.There was a suspicion of head fracture.The preoperative puncture showed no evidence of an infection in the microbiological cell count analysis.Therefore, the working hypothesis of a proximal femur lysis due to metal wear.A blood sample for metal ions was taken, but unfortunately the sample was lost on the way to the (b)(6).The patient has been complaining for some time about pain in the area of the left hip, more specifically proximal lateral thigh under load.In the period between implantation and revision there were no incidents such as dislocation, noise, shortening of leg length, or trauma.Pain and limited range of motion were complained.Intraoperative finding: wear particles with the corresponding metallic discoloration were seen in the joint.There is no clinical indication for infection.There is a relatively loose sliding pairing between neck and head.There are signs of loosening of the cup.Histology finding: periprosthetic membrane of wear-induced type with little accompanying synovitis.No malignancy.The finding is matching with the indicated metal wear at state of a left hip prosthesis.Patient information: female, born (b)(6), height: 170 cm, weight: (b)(6) bmi: 20.Intraoperative images of the wound are not available.Phone call with the surgeon from 28 sep 2020: the following can be summarized from the phone conversation: ct and x-rays showed osteolysis in the left acetabulum and femur, mainly in the proximal femur region.There was a suspicion of head fracture based on the ct scan.Intraoperative: a grey - dark tissue discoloration was seen.The sample sent for histology was membrane tissue from the head-neck region.Intraoperative: the shell was loose, the insert was stable in the shell.Intraoperative: the head/stem taper connection was loose, the head could be removed by hand, there was no need for an instrument.Product evaluation: as-received condition: the retrievals were received all together in a container filled with formalin solution without protection against further damage during shipping.Visual examination: on the anchoring side of the allofit shell there are bone attachments visible.All around the anchoring surface, the teeth of the shell¿s macrostructure show some damage in the form of polished areas.Closer inspection with a low power microscope type leica mz16 a revealed a pattern in these zones.On the inner side of the shell, two opposite polished areas and some scratches can be observed in the pole region.On the inner side of the shell¿s rim there are two opposite polished marks visible.Close to one of these marks a coarse scratch can be noticed on the spherical calotte.The following can be observed on the anchoring side of the insert: set of indentations from the shell¿s fixation spikes.Imprint of the shell¿s pole plug on the polar region of the insert.Pole pin is slightly deformed on one side.Several indented lines across the anchoring side of the insert including the rim, at approximately 45°.Large cut-in damage close to the rim and opposite smaller cut-in damage, coarse scratch nearby.Backside changes, most predominantly on the side where the indented lines were observed.Small indentations in different locations.The articulation surface of the insert is completely covered with coarse scratches.In the middle of the articulation surface there is a round region, approximately 1 cm in diameter, exhibiting a whitish roughened appearance.On the articulation surface a polished region can be seen (corresponding to the area with backside changes on the anchoring side) which points to the loaded area.Closer inspection of the articulation surface with a binocular revealed a region where the machining marks are still recognizable, which indicates the unloaded area.The rim on the articulation side exhibits several scratches and cuts.On the articulation surface and on the bottom bevel of the sulox head numerous metallic smears of different size and intensity are visible.The head taper shows the commonly observed material transfer from the stem taper indicating proper fixation of the head on the stem and an artefact which can be ascribed to removal.Revision damage in the form of scratches and nicks can be observed on taper, neck and shoulder region of the müller stem.The proximal and distal end of the taper have a shiny appearance compared to the middle part of the taper.At the distal taper end, an almost circumferential small polished stripe sometimes extending into the blasted surface of the neck is recognizable.The taper surface was further investigated with a low power microscope type leica mz16 a as well as with a light microscope type leica dmrx.The proximal end of the taper shows some deformation leading to increased width of the crests and decreased width of the grooves in comparison to the structure in the middle part of the taper and the structure of a pristine taper.The distal end of the taper shows as well deformation with increased width of the crests and decreased width of the grooves.However, on the crests, scratches in different directions and nicks can be observed.Several dark spots can be seen on the medial and anterior side of the stem¿s collar.These can most probably be attributed to the use of an electrocautery instrument during surgery.There are no cement attachments on the anchoring region of the stem.On the posterior side of the latter a shiny polished area can be observed on the lateral face and bottom of the stem¿s collar as well as directly below the collar extending to the lateral side.A smaller shiny polished area can also be recognized on the posterior side at the beginning of the grooves.On the medial and lateral side of the stem¿s anchoring region slightly polished areas of various sizes, some with a dark appearance, can be seen.On the medial side, these polished areas are more predominant in the proximal and middle stem region and get sparser towards the stem¿s tip.Review of product documentation: device purpose: all involved devices are intended for treatment.Product compatibility: the compatibility check was performed from www.Productcompatibility.Zimmer.Com and showed that the product combination was approved by zimmer biomet.Dhr review: review of the device history records identified no deviations or anomalies during manufacturing.Conclusion: it was reported that there was suspicion of wear at the head-stem taper interface with osteolysis without indication for infection.The quality records show that all specified characteristics have met the specifications valid at the time of production.Therefore, the investigation did not identify a nonconformance or a complaint out of box (coob).According to the information available in the bfarm user report the prosthesis was revised after 4 years and 8 months in vivo due to suspicion of wear at the head-stem taper interface with osteolysis without indication for infection.Later on more information became available via e-mail and phone conversation with the surgeon.Based on this information the x-rays and ct would have shown pronounced lysis and a gradual migration of the cup and intraoperatively the cup would have been found to be loose.On the shell at hand, the damage seen on the shell¿s macrostructure rather points to the use of an instrument during revision than signs of loosening.Based on the set of indentations from the shell¿s fixation spikes and the imprint of the shell¿s pole plug seen on the anchoring side of the insert it can be assumed that it was properly seated in the shell.The two opposite cut-in damage seen on the rim of the insert is matching the location of the damage seen on the inner side of the shell.This indicates that the insert was still properly seated in the shell at the time of revision surgery, when the insert was removed from the shell.During the phone conversation it was mentioned that intraoperatively, the insert was stable in the shell.However, the indented lines across the anchoring side of the insert and the slightly deformed pole pin indicate that at one point in time the insert was in a tilted position repeatedly pushed against the edge of the shell.At what point in time and how this situation could occur stays unknown.The articulation surface of the insert is completely covered with coarse scratches and in the middle there is a round region, approximately 1 cm in diameter, exhibiting a whitish roughened appearance.This type of damage could be consistent with a situation where the stem taper moved against the articulation surface of the insert without the head.However, since at revision the head could allegedly be removed by hand, this does not seem to have happened during the time in vivo, provided that there was no revision in between implantation and revision.According to the received information there was a suspicion of head fracture based on the ct made before revision.During revision surgery it was said by the surgeon that the head was loose and could be removed by hand.The head was received intact.There are no signs of wear at the head-stem taper interface.Closer inspection of the taper structure showed damage in the form of deformation of the taper structure at the proximal and distal end of the taper.This damage does not reflect the situation on the head taper which shows the commonly observed material transfer from the stem taper indicating proper fixation of the head on the stem and an artefact which can be ascribed to removal.The origin of the damage seen on the stem taper stays unknown.On the stem¿s anchoring region there are no remains of cement attachments and signs of loosening in the form of polished areas were found.The latter indicate that some wear was generated from the surface of the stem.Whether this could have contributed to the reported osteolysis, the tissue discoloration found intraoperatively and histology findings or if there were other influencing factors remains unknown.Based on the visual examination of the retrievals at hand, it seems that the amount of wear particles generated by the loosening of the stem would not be sufficient to be imaged on a ct.All retrievals were sent together in one container and were not protected against damaging each other during shipping.Thus, it stays unknown how much this contributed to the phenomena seen on the parts.In summary, based on the retrieval investigation and the information received this case stays inconclusive.The need for corrective measures is not indicated and zimmer (b)(6) considers this case as closed.Zimmer biomet¿s reference number of this file is (b)(4).
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