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Investigation results were made available.As the case at hand is a legal claim it is not suspected that the devices or additional information are being submitted for review.Zimmer gmbh winterthur legal department have already passed all information that was received from the lawyer, to our complaint handling department.By experience zimmer gmbh never gets more information except for the one that has been already covered in the final report.Patients¿ advocates only provide to zimmer gmbh as much information as they are willing to share to protect the rights of their clients.All information which has been provided for this particular case is already covered in the final report.Nevertheless, should additional information become available to us, a follow up report will be submitted.A technical investigation was not possible to be performed, as the device(s) were not at hand for investigation.However, based on the available information the investigation is conducted with outcome as follows.Event description: it was reported that that the patient had a metal on metal hip prosthesis implanted on (b)(6) 2010 which was explanted on (b)(6) 2019.The patient suffered pain a few months after the implantation.Later on, signs of trochanteritis and loosening became evident together with the high levels of metals in the body and the appearance of a cyst in the upper acetabular region.Review of received data: - no medical data relevant to the case has been received.- legal document: a legal document was received in spanish.No additional event related information was identified.Product evaluation: - visual examination: the allofit shell shows slight damage probably deriving from the revision surgery on the rim (e.G.Scratches) and on the anchoring side.There are bone attachments visible on the anchoring side of the shell.On the inner side of the shell a circular polished line can be seen around the polar screw.The latter is slightly damaged.Bone attachments can be observed in the screw holes.One of the screw holes is partially closed by bone attachments.On the anchoring side of the metasul alpha insert, there is a set of indentations from the shell¿s fixation spikes.These indentations are enlarged.A further indentation can be recognized close to one of the enlarged indentations.Its origin stays unknown.The contour of the shell¿s screw holes is imprinted on the anchoring side of the insert.For at least two of the shell¿s screw holes, a second partially imprinted contour slightly offset to one side can be seen.On the entire anchoring surface the machining marks are still visible.Slight backside changes can be observed in the area of the imprinted shell¿s screw holes.The latter is intact.The polyethylene is slightly yellow discolored.On the articulation side of the insert some damage can be noticed on the polyethylene rim in the form of scratches, most probably made during revision surgery.On one side of the polyethylene rim a slightly polished area can be seen.Slight signs of embrittlement can be recognized at one end of the hooded region.There are no signs of autoclaving (e.G.Barely visible markings, oval deformation, air bulges) on the metasul alpha insert.On the articulation surface of the metasul inlay a greyish matt area can be observed close to the hooded region.The bevel of the spherical calotte adjacent to the hooded region is worn on approximately half of its circumference.An area with pits arranged in arrow-shaped formations can be seen approximately in the middle of the worn region on the adjacent spherical calotte.Numerous fine scratches are visible on the articulation surface of the metasul inlay.Closer inspection of the articulation surface of the inlay with a low power microscope revealed another matt area (less pronounced) opposite to the matt area visible by the unaided eye.Both matt areas consist of micropits.Some spots, most probably deriving from the use of an electrosurgical instrument during surgery can be recognized on the inlay¿s rim.On the articulation surface of the metasul head a borderline between the loaded and unloaded areas is almost completely visible.The borderline is more pronounced and partially palpable on one side of the head.Organic deposits can be recognized along the unloaded side of the more pronounced borderline, whereas on the loaded side matt greyish areas can be seen.Several matt greyish areas can also be noticed around the head¿s pole.A matt greyish line is seen from the pole towards the equator.Several coarse scratches and some spots from an electrosurgical instrument can be recognized on the articulation surface of the head, most probably deriving from revision surgery.The articulation surface of the head was investigated under the light microscope at 200-times magnification with differential interference contrast (dic).As already visible by the naked eye, the borderline between the loaded and the unloaded area that is covered by organic deposits is well recognizable.The matt greyish areas consist of micropits.In the loaded area that doesn¿t appear matt greyish, fine scratches can be recognized and the carbides, which protruded slightly in the original surface state, are leveled.The original surface state with slightly protruding carbides is still visible in the unloaded area.The head taper is inconspicuous.Revision damage in the form of scratches, nicks and instrument marks can be observed on the taper, neck, shoulder and proximal anchoring region of the metabloc stem.On the stem¿s neck and shoulder there are several blue-brownish spots, most probably deriving from the use of an electrosurgical instrument during surgery.On the stem¿s anchoring surface remains of bone attachments can be seen.Apart from the revision damage, the stem taper is inconspicuous.- wear measurement: the wear measurements of the articulation surfaces of the metasul head and metasul alpha insert were carried out on a 3d measuring machine.The total, linear wear value for the head is 134.6 m which results in an annual wear rate of 16.0 m.For the metasul inlay the cmm measurement detected a wear zone close to the bevel.The total, linear wear value amounts to 338 m resulting in an annual wear rate of 40.2 m.Due to the measuring method it is not possible to measure the entire articulation surface of the inlay.The measurement only covers the surface from the center of the component up to 80°.Due to the position of the loaded zone it has to be assumed that the wear area could not be measured entirely.Therefore, the wear value indicated above does not reflect the true amount of wear.For a metasul pairing with diameter 28 or 32 mm retrieved within the first year an average wear of 27.8 m / year per pairing was found.Retrievals explanted after two and more years in-vivo had an average wear rate of 6.2 m / year per pairing.Review of product documentation: - device purpose: all involved devices are intended for treatment.- product compatibility: the compatibility check was performed 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.- ncr(s): lot 2545516: 1 part was scrapped as it was used for adjusting after fracture of the instrument during manufacturing (ncr# 200144724).Conclusion: according to the received information the hip prosthesis was implanted in 2010 and revised in 2019 after 8 years and 5 months in vivo.The legal document states that the patient suffered pain a few months after the implantation and later on signs of trochanteritis and loosening became evident together with high levels of metals in the body and a cyst in the upper acetabular region.As there is no clinical information (e.G.Surgical reports, complete x-ray follow-up, histological report, blood test results, etc.) at hand the further background of the situation stays unknown.Especially, why the pain started, how it was treated and whether it continued over the time in vivo of the implants remains unclear.Both the shell and the stem show bone ongrowth on the anchoring surfaces.Signs of loosening could not be recognized.There is nothing to report about the taper surface of the head.On the stem taper only some revision damage can be observed.On the articulation surfaces of the metasul head and inlay matt greyish areas consisting of micropits as well as some arrow-shaped formations could be recognized.According to the size of the micropits observed on the metasul pairing is in the range of 1 - 2 m in diameter and up to 0.5 m in depth.The micropits and the arrow-shaped formations can be attributed to surface fatigue.On the head a borderline between the loaded and unloaded areas is almost completely visible and slightly palpable on one side.The appearance of the articulation surface of the metasul inlay points to a rim loading situation.Compared to the annual wear rate measured on the metasul pairing can be considered elevated.However, due to the position of the wear zone of the inlay the wear area close to the bevel could not be measured completely.Rim loading is influenced by the position of the implants (mostly cup inclination and anteversion).Based on the retrieval investigation it can be hypothesized that at one point in time it came to a position of the implants that triggered a subluxating situation and a rim loading situation developed.However, as the x-ray follow-up is not at hand, the position of the components during the time in vivo stays unknown.Therefore, it cannot be determined if the components were implanted according to the surgical technique and / or if the position of the implants changed over time in vivo.It is unknown if the patient has in addition to the total hip endoprosthesis any other joint replacements that could have contributed to the symptoms.Without clinical information the reason for the reported symptoms of the patient cannot be further evaluated.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).Based on the given information and the results of the investigation, we were not able to identify a specific root cause for this issue.The need for corrective measures is not indicated and zimmer switzerland manufacturing gmbh considers this case as closed.Zimmer biomet's reference number of this file is (b)(4).The following reports are associated with this event: 0009613350-2019-00815-2, 0009613350-2020-00477-1, 0009613350-2020-00474-1, and 0009613350-2020-00475-1.
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