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Additional information which was received on nov 23, 2020.The manufacturer received x-rays, patient initials, surgical notes, and other source documents which will reviewed as part of ongoing investigation.Should any additional information become available or an investigation result be available, that changes this assessment, an amended medical device report will be submitted.Zimmer¿s reference number of this file is (b)(4).
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D10 concomitant medical products: - item# 0100010413, lot# 2013296, alpha insert me neutral mm/28.- item# 192807, lot# 2124204, metasul hd 28mm l 12/14.- unknown fitek cup hip impl win gen, item-/lot# unknown.Event description: it was reported that the poducts were implanted on (b)(6), 2002 and revised on (b)(6), 2020 due to periprosthetic fracture.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.- x-rays: (b)(6) 2002 - situation before implantation surgery.(b)(6) 2002 - situation before implantation surgery.(b)(6) 2002 - a cementless total hip endoprosthesis is implanted on the left side.The inclination angle of the cup was measured and amounts to approximately 47°.In the pelvic overview there is a calcium density visible above the stem shoulder lateral to the stem¿s neck.A possible cortical fissure can be recognized above the lateral stem shoulder at the level of the fossa trochanterica.(b)(6) 2002 - compared to the previous pelvic overview there are no relevant changes.The inclination angle of the cup was measured and amounts to approximately 47°.(b)(6) 2003 - compared to the previous studies of 2002 there are no relevant changes.The inclination angle of the cup was measured and amounts to approximately 49°.(b)(6) 2008 - compared to the previous study of 2003 there are no relevant changes.The inclination angle of the cup was measured and amounts to approximately 49°.The possible cortical fissure observed above the lateral stem shoulder at the level of the fossa trochanterica seems to be bridged by bone but the gap appears to be unchanged.(b)(6) 2020 - compared to the previous study of 2008 a periprosthetic fracture in the proximal femur is clearly visible.The inclination angle of the cup was measured and amounts to approximately 51°.(b)(6) 2020 - situation after revision surgery.The inclination angle of the cup was measured and amounts to approximately 49°.- letter from the surgeon dated (b)(6) 2020: the patient received a total hip endoprosthesis on the left side consisting of a fitek cup combined with metasul insert, metasul head and a cls stem on (b)(6) 2002 in the kantonsspital winterthur.On (b)(6) 2020 the patient suffered a periprosthetic fracture of the left proximal femur due to a tripping fall.The revision surgery was performed because of the fracture.So far the patient was asymptomatic concerning his hip apart from a shortening of the leg that had been present since the implantation of the prosthesis.There are no chromium and cobalt levels available.Intraoperatively, only heterotopic ossifications of the joint capsule were seen but no relevant reaction due to wear or osteolysis.- surgical report of revision, (b)(6) 2020: diagnosis: multi-fragmentary periprosthetic fracture of the left proximal femur type ucs b2 after implantation of a total hip prosthesis (thp) (transgluteal with metal-on-metal pairing) in (b)(6) 2002.Indication: the day before, the patient suffered the above mentioned fracture in a fall while hiking.After the implantation of the prosthesis already a leg shortening of about 15 mm was complained.Due to the fracture the stem got loose even though if it is now again diaphyseally anchored.There is a retrotorsion and an additional shortening of about 10 mm.Because of the type of fracture the revision of the stem is given.The cup has a metal-on-metal-pairing with an inclination of 55°.If the cup is firmly fixed only the insert is changed for a combination with a 36 mm head to limit the risk of dislocation.Technical procedure: a kocher-langenbeck approach is used.The fracture at the innominate processus is difficult to identify.The osteotomy and progressive cranial and anterior capsulectomy are conducted.Samples for microbiological and histopathological examination are taken at various locations.The prosthesis is dislocated and the clearly loose stem can be knocked out retrograde.The capsulectomy is completed whereby the little reaction due to wear particles is debrided.The cup¿s rim is exposed.The cup is clearly firmly integrated in the bone.The insert is removed using a chisel.There are no deposits in the interface between shell and insert.Irrigation is performed and a durasul alpha insert mm/36 is placed.The further report describes the implantation of a straight revitan stem 18x140 mm with a 65 mm proximal part and a biolox delta head 36/l as well as the repositioning of the various bone fragments.- histological report, input (b)(6) 2020, output (b)(6) 2020: the report can be summarized as follows.Two parts of tissue were examined, one included a portion of tendon.Diagnosis: resected part of the joint capsule with extensive fresh bleeding, fibrosis with multifocal myoxid degeneration and amyloidosis and with small-sized xanthomatous inflammation (left femur).Product evaluation: - visual examination: in the as-received condition the metasul head was still mounted on the taper of the cls stem.For easier handling and permitting also investigation of the taper surfaces, the head was disassembled during the examination.The cls stem shows some bone attachments on all anchoring surfaces.Coarse damage most probably due to the removal of the stem in the form of scratches and instrument marks are visible mainly on the lateral side as well as on the posterior side.The portion of the stem taper, that was in contact with the taper of the metasul head, is dark discolored especially in the proximal third also including the face surface.The taper of the metasul head is inconspicuous.The proximal area, that was not in contact with the stem¿s taper, is discolored as well.On the articulation surface of the metasul head some coarse scratches and few smearing as well as damage on the bevel deriving from disassembly can be recognized.The articulation surface was inspected under the microscope at 200-times magnification with differential interference contrast (dic).In the loaded area zones with different density of scratches could be observed.The carbides, which protruded slightly in the original surface state, are mainly levelled while they are at least still partially visible in the unloaded area.The polyethylene liner of the metasul alpha insert is very slightly yellowish discolored what is mainly recognizable around the pole pin.The latter is almost completely fractured and shows subsurface cracks.Slight backside changes can be seen around the polar area as well as on one side of the spherical region between the two chisel marks deriving from the removal of the insert from the shell.Further, the anchoring side of the insert shows several fine scratches/ nicks.Along the liner¿s rim areas with subsurface cracks can be recognized partially extending to the articulation side whereby two of those areas are at the chisel marks.In the polyethylene several coarse and finer scratches / indentations are present.There is no obvious change of the position (subsidence / tilting) of the metasul inlay in the liner.Numerous fine scratches can be seen on the articulation surface of the metasul inlay.Closer inspection with a low power microscope revealed a possible borderline between the loaded and unloaded area on the spherical calotte close to the bevel of the inlay.Smearing on the bevel and / or rim of the inlay could not be detected.Review of product documentation: - device purpose: all involved devices are intended for treatment.- product compatibility: the product combination was approved by zimmer biomet.- dhr review: review of the device history records identified no deviations or anomalies during manufacturing.Conclusion: the total hip endoprosthesis had to be revised after almost 18 years in vivo due to a tripping fall of the patient resulting in a periprosthetic fracture of the proximal femur.Until then the patient was asymptomatic concerning his hip apart from a shortening of the leg that had been present since the implantation of the prosthesis.During revision surgery the cls stem and the metasul pairing were removed.The fitek shell was left in place as it was firmly fixed.The inclination angle of the cup was measured on the x-rays provided.There are slight changes in the inclination of the cup (range: approximately 47° to 51°).Apart from the damage due to the revision surgery the retrieved components are inconspicuous.The cls stem does not show signs of loosening or impingement.The discoloration of the stem¿s taper indicates a thicker oxide film while the discoloration in the head¿s taper could rather point to organic deposits.There are no signs of fretting and / or corrosion on the taper surfaces.A part of the borderline of the loaded zone of the metasul inlay was found on the spherical calotte close to the bevel of the inlay.This location is most probably a result of the higher inclination angle.However, no signs of impingement, subluxation and rim loading could be observed on the articulation surfaces of the metasul pairing.The anchoring side of the metasul insert partially exhibits a slightly yellowish discoloration and backside changes.The subsurface cracks seen on the rim and the pole pin of the polyethylene liner are the result of material oxidation.This may have contributed to the fracture of the pole pin probably occurring due to the removal from the shell.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 investigation the reported event can be confirmed.Based on the given information and the results of the investigation, we identified the root cause to be the tripping fall of the patient resulting in the periprosthetic fracture of the proximal femur.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).
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