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This follow-up report is being filled to relay additional information, which was unknown at the time of the previous medwatch.Item number: 0100401055.Item name: revitan, proximal part, conical, uncemented, 55, taper 12/14.Lot#: 2340623.Item number: 14280720.Item name: cocr head 28/+4, l 12/14.Lot # 2350609 item number: unknown.Item name: hip inlay.Lot#: unknown.A cause for this specific event cannot be ascertained from the information provided.As soon as supplemental information becomes available, an updated report will be submitted.Zimmer biomet¿s reference number of this file is (b)(4).
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Investigation results were made available.Review of event description: it was reported that the product was implanted on unknown date and revised on (b)(6), 2020 due to pain, loosening from distal pin and implant fracture.Review of received data: - x-rays: pelvis overview and second view taken on (b)(6) 2020: on the pelvis overview it can be seen that the proximal part of the revitan stem is tipped medially and the distal end of the connection pin is shifted laterally.Along the lateral side of the connection pin a fracture fragment of the distal part of the stem can be seen.A radiolucent gap can be recognized between the cortical bone and the medial and lateral side of the proximal stem part.The gap is bordered on the bone side by a sclerotic line.On the medial side, the gap extends slightly to the proximal region of the distal stem part.On the second view a radiolucent gap can be observed between the cortical bone and the anteromedial and posterolateral side of the proximal stem part.On the anteromedial side, the gap extends slightly to the proximal region of the distal stem part.The most proximal cerclage of the four cerclages placed is fractured in several locations.Pelvis overview and second view taken on 20 mar 2020: the x-rays show the situation after the revision of the revitan stem and are not evaluated.- revision report of (b)(6) 2020: diagnosis: stem fracture of a total hip prosthesis on the left side after implantation of a revitan in 2008 indication: at a fracture of the stem after already pre-existing complaints, probably fatigue and metal wear, it came to a fracture during the holidays in brazil.The patient came back and came to the consultation a week ago.The radiological check showed a fractured revitan stem.The patient had a 28 mm head.Apparently the patient had 2-3 dislocations after the last surgery and therefore also a revision of the inlay and head (change to larger head) is targeted.Procedure: the hip joint is accessed through the old scar, which is extended distally.The third uppermost cerclage and the 8-loop cerclage are removed.A stepped trochanteric flip osteotomy extended into the femur is performed.A small fracture occurs at the connection between the femoral fragment and the metaphysis when uncovering the prosthesis.The femoral and medial parts remain intact.The neocapsule is discolored black with metal debris.The wear material is as much as possible completely debrided.The cup is exposed and is seen to be correct.The hip is dislocated without problems.The proximal part, which has broken off from the distal stem part, is knocked out and the intermediate piece is removed.Even after 5 attempts the distal part of the stem cannot be removed therefore the femur is split until the most distal cerclage.Then the part can be removed without problems.Further, the report describes the steps to place a new durasul insert 36/mm, to implant a wagner revision stem (19/225) and a biolox delta head (36l) and applying cerclage wires and screws.- swissmedic report of (b)(6) 2020: apart from the information already mentioned above, the swissmedic report does not contain additional information relevant to the investigation.- zimmer biomet product experience report (zper): the zper informs about the height and weight of the patient.Note of the author: the given height and weight of the patient result in a bmi of 36.4 which can be classified as obese class ii (severely obese) according to the bmi scale (bmi 35 - 40) (1).Product evaluation: - visual examination: the revitan stem was received disconnected at the connection between the connection pin and the distal stem body.The proximal part of the stem and the connection pin were still assembled.The proximal and distal part of the revitan stem exhibit some damage such as scratches, dents, a bore hole and instrument marks most likely deriving from revision surgery.On the proximal part of the revitan stem, a circumferential dark line can be seen in the distal region of the taper.The rest of the taper surface is slightly dark discolored.A horizontal shiny polished stripe can be seen on the posterior and medial side of the anchoring region of the proximal part of the stem.Within the stripe on the medial side two worn horizontal marks can be observed.In addition, polished areas can be seen above and below the stripe on the medial side.On the posterior side slight horizontal polished spots/lines can be seen above and below the stripe.There are no bone attachments noticeable on the proximal part.The distal face surface of the proximal part is polished on the posteromedial and anterolateral side.The medial shoulder is worn.There is also a polished area medially on the blasted surface of the connection pin which extends slightly to the anterior and posterior side.The press-fit region of the connection pin is not anymore in its original condition and shows a mixture of polishing, smearing and corrosion.The anterolateral side of the distal conical region of the pin exhibits polishing, smearing and an elliptical shaped groove.The proximal 20 mm of the anterolateral side of the distal stem body is fractured.The fractured fragment/s was/were not received for investigation.The remaining proximal face surface of the stem body and the face surface of the posterior shoulder are worn and deformed.Posteromedial, the remaining inside of the stem body shows areas worn to various degrees as well as still intact areas that are blueish discolored.Due to the wear the material thickness is clearly diminished medially proximal.Further down a new ledge can be recognized on the lateral side.Just above the new ledge the thickness of the stem body is diminished to approximately 0.7 mm and has a sharp edge.The fracture surface was investigated with a low power microscope (leica mz16 a) and in some regions a structure that might point to fatigue could be recognized.Based on this structure it seems that the fracture originated in the area with the diminished material thickness just above the new ledge.On the distal part of the revitan stem there are some bone attachments on the distal half of the anchoring surface.On the articulation surface of the cocr head an area with smeared material could be recognized.On the distal region of the head taper there are some signs of fretting and corrosion.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.- ncr(s): no ncr with a potential correlation to the reported event was found.Conclusion: according to the received information the revitan stem was implanted in 2008 and revised approximately 12 years later due to a fracture of the stem / loosening of the connection pin from the distal stem.Apparently the patient had several dislocations after the last surgery and therefore the inlay and the head were also revised.The insert and the fractured fragment of the distal part of the stem were not received for investigation.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).Only x-rays taken shortly before and after revision of the revitan stem were received.The x-rays before revision show the revitan stem tipped medially and a fracture fragment of the distal part of the stem can be seen along the lateral side of the connection pin.Around the proximal part of the revitan stem radiolucent gaps can be observed which extend slightly to the proximal region of the distal stem part medially and anteromedially.However, as the complete x-ray follow-up is not at hand, the bone support situation immediately after the implantation of the stem and how it developed over time in vivo stays unknown.In agreement with the x-rays, the retrievals show a fracture of the proximal anterolateral side of the distal stem body and a disconnection of the pin from the distal stem body.Bone attachments could be observed on the distal half of the distal part of the stem but not on the proximal part.The horizontal shiny polished stripe and the worn marks seen on the proximal part of the stem point to a contact between the part and the osteosynthesis material.The polished areas on the medial and posterior side indicate movement between the part and the surroundings.Today it is known that for patients with severe proximal deficiency, a surgeon should consider surgical options to ensure proximal bone support (such as medial and/or lateral strut grafts) or switching to a monobloc revision stem (2).At the time of implantation this was not known and respective guidance could not be provided to the surgeon.Based on the received information and today¿s knowledge which was unknown in 2008, it can only be assumed that the proximal bone support of the revitan stem was suboptimal during the time in vivo while the distal stem part was well fixed.The bone support situation in combination with other factors (e.G.The patient¿s bmi of 36.4) could have led to an overload of the stem resulting in a loosening of the connection pin from the distal stem body.After loosening, the connection pin could move inside the stem body and subside together with the proximal part.The subsidence led to contact between the face surfaces of the proximal and the distal part resulting in wear on both surfaces.Additionally, the load was not anymore completely borne by the connection pin.The loosening of the pin resulted in wear on the inside of the stem body.This allowed a little by little tipping of the pin to medial so that its distal end could rest on the inside of the stem body and form a new ledge distally lateral and worn areas posteromedially.Due to the wear the wall thickness of the stem body is particularly diminished distally lateral and proximally medial.The fracture of the anterolateral side of the distal part of the revitan stem is probably a concomitant of the changed load situation and possibly due to the diminished thickness of the stem body distally lateral.On the connection pin a mixture of polishing, smearing and corrosion was observed.The first two phenomena are most probably concomitants.However, it remains unclear whether the latter could have had an influence on the failure mode or is only a concomitant as well.The area with smeared material seen on the articulation surface of the cocr head could possibly derive from the several dislocations the patient had.Based on the given information and the results of the investigation, we were not able to identify a specific root cause for this issue.References: (1) wikipedia body-mass-index accessed on 28 may 2021 https://en.Wikipedia.Org/wiki/body_mass_index (2) revitan straight revision hip system - surgical technique, 06.01109.012x - rev.2 2016-11 a4 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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