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Event summary: the incident report form of the (b)(6), which was filled in by prof.(b)(6), was received.The section of the detailed event description states that the revitan stem was implanted in 2010.The surgery included the change of a cemented standard stem to a revitan stem without any difficulties.On (b)(6) 2014 the patient experienced sudden pain without external event.An x-ray was taken and showed a fracture of the connection between the distal and proximal part.Operatively the fracture of the connection pin was then confirmed.No other obvious changes e.G.Metallosis, issues with the articulation pairing etc.Could be identified.The product experience report (per) did not state any additional information that would influence the investigation.Review of received data.No further due diligence required as all required information to support the conclusion is available or was already requested.Three pictures have been received.Two of the pictures are dated and were taken from an x-ray displayed on a computer monitor and have therefore a bad quality.Based on the visual examination it is assumed that two pictures show the same x-ray.The x-ray, dated (b)(6) 2013 shows the ap view of the pelvis.The prosthesis appears to be intact showing a well anchored distal part.It seems that there are radiolucent lines visible in zones 1 and 7 according to gruen.However, without previously taken x-rays it is not possible to determine if the radiolucent line existed already after the implantation or developed over the past years.The gap between the distal and proximal stem part is located above the trochanter minor.The x-ray taken on (b)(6) 2014 shows a clearly fractured connection pin with a medially tipped proximal part.No obvious changes regarding the bone structure can be detected between the x-rays taken on (b)(6) 2013 and (b)(6) 2014 respectively.Comments on component position and bone changes around the revitan stem cannot be made as the entire x-ray follow-up is not available.Implantation report of (b)(6) 2010 bone impingement after hybrid hip tep on the right side 2009 is given as indication for the revision surgery to exchange the stem and the insert.After opening the joint, except for the reduced offset, there are no conspicuous findings and no indication of implant impingement or inflammatory situation and the cup is in a correct anteversion.After dislocation of the femur it shows that the stem is a bit in a reinforced antetorsion position which increases the offset reduction.Therefore, the decision is made to change the stem with an implant that has a higher offset and still enables the leg length compensation.The stem and the bone cement are removed without substantial bone loss.Then a revitan stem and a durasul-insert are implanted without any described problems.The trial reduction confirms the correct implant position with a good offset.It shows no luxation tendencies for all movement tests.Discharge report of (b)(6) 2010.The patient was hospitalized between (b)(6) 2010 and (b)(6) 2010 due to a revision of the femoral component performed on (b)(6) 2010.Postoperatively an anemia due to bleeding developed.Because of the multiple medical comorbidities, from (b)(6) 2010 the patient was transferred to the intensive care unit for monitoring until the patient¿s vital parameters normalized.The report does not contain further relevant information.Revision report of (b)(6) 2014: the indication for surgery is given due to a connection pin fracture of the revitan stem.According to the preoperative consultation, stem and insert have to be changed, which requires a partial osteotomy and femoral window to remove the distal part.After opening the joint a sample was taken.There are some inflammatory changes, but there is no evidence of a periprosthetic infection (preoperative puncture was also negative).Slight changes due to metallosis are observed.The proximal body and the inlay are removed and careful debridement is performed.A femoral flap is made while leaving the trochanter part intact.The now mobilizable stem is knocked out from distal.The femur is secured with cerclage wires.Then the femur is prepared for the new stem which is implanted without noted problems.The x-ray check shows a correct implant position and regular leg length.Additionally, a zimmer complication report was received that informs about the fracture of the revitan stem, however, no additional information relevant to the case is included.Discharge report of (b)(6) 2014.The patient was hospitalized between (b)(6) 2014 and (b)(6) 2014.It is reported that there was a serous secretion from the proximal area of the wound.As in the course it was not dropping, a joint conserving septic revision was performed whereby head and insert as well as the cerclage wires were changed on (b)(6) 2014.Devices analysis: when receiving the retrieved components, the nut was no longer mounted to the connection pin and all components were received in one biobottle without any protection.Therefore, it is possible that some of the damage on the products derived from the unprotected shipping.The connection pin of the revitan stem is fractured in the area not blasted.The fracture is located approx.4 mm below the proximal end of the distal part.The fracture surfaces point to a fatigue fracture with the origin located on the lateral side.Macroscopically, no defects that could have favored or triggered the fracture were found on the fracture surfaces.On the proximal fracture part of the connection pin is a circumferential stripe with a width up to 2 mm which reveals surface changes e.G.Signs of fretting corrosion, corrosion and metal smearing.Additionally, possible microcracks could be observed within the stripe of surface changes.Both parts of the revitan stem show some slight damages from the revision surgery such as nicks, scratches and so on.Almost no bone ongrowth can be seen on the anchoring surface of the proximal part.There is one spot on the lateral side at the distal end where there is some remain of bone attachment.On the posterior side the proximal part exhibits some polished spots.The distal part features bone attachments in the anchoring region.On the lateral side there is a long coarse scratch which probably derived from the instrument which freed the part from the bone.The proximal face of the distal part has some slight scratches which probably also derived from the removal or from the contact to the connection pin.The bottom edge of the anterior nose is slightly damaged.The conical nut was received disassembled from the rest of the prosthesis but neither damage nor circumferential marks on the lateral surface were seen.Therefore, it is assumed that it was still fixed to the stem at time of the revision surgery.The biolox delta head looks inconspicuous with some slight metallic smearing deriving most likely from the removal.Based on this visual examination the reported event can be confirmed.Review of product documentation all involved devices are intended for treatment.The compatibility check was performed from (b)(4) and showed that the product combination was approved by zimmer biomet.Dhr review: the quality records show that all specified characteristics (material, dimensions, surface, etc.) have met the specifications valid at the time of production.Conclusion summary: approximately one month before the revision surgery, on (b)(6) 2013 an x-ray was taken.It is unknown if there was a special reason for taking the image.On the x-ray it seems as the stem is still intact but it cannot be excluded that the fracture has already started at that point of time.It is also possible that the proximal part tipped posteriorly or anteriorly respectively which is unknown since there is no x-ray with a lateral view available.The gap between the distal and proximal stem part is located above the trochanter minor which limits the medial bone support for the proximal stem part.From the bone ongrowth seen on the revised components, it is assumed that the distal part was well fixed.No bone ongrowth but possible signs of loosening were seen on the proximal part and the x-rays showed radiolucent lines around the proximal part.Therefore, it is assumed that the proximal part was loose.The connection pin is fractured due to fatigue in the area not blasted just some millimeters below the proximal end of the distal stem part.On the proximal fracture part there is a small circumferential stripe revealing surface changes.It is unknown if these signs existed already before the start of the fracture and are associated with the fracture or developed exclusively as a concomitant phenomenon.There is no complete x-ray follow-up and the received surgical notes did not include relevant information that would indicate any contributing factors.Therefore, it can only be assumed that the fracture was not triggered by a single factor, e.G.Material failure.There were rather several factors, e.G.Limited proximal bone support, the patient¿s weight and behavior or the observed surface changes that may have contributed to the fracture.However, it is unknown to which extent each of the factors finally influenced the failure of the stem.The investigation results did / did not identify a non-conformance or a complaint out of box (coob).Therefore, based on the available information and the investigation, we were not able to identify an exact root cause for this issue.The need for corrective measures is not indicated and zimmer (b)(4) considers this case as closed.(b)(4).
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