Modulare Metall auf Metall Hüftprothesen: Stand der Wissenschaft und Technik 2003

Eine große Frage, die Sachverständige in diversen Verfahren gegen die Firma Zimmer zu klären versuchen, lautet: Welche Kenntnisse hatte man bei Einführung der Durom Metasul LDH Hüftprothese über die Probleme der modularen Schaft – Kopf Verbindung.
Dazu werden zugängliche Publikationen gesichtet und bewertet. Nicht berücksichtigt werden interne Forschungen und Erkenntnisse der einzelnen Hersteller, da diese sich weigern, die entsprechenden Unterlagen vorzulegen.

Die Firma Zimmer und einige Sachverständige vertreten die Meinung, dass 2003 keinerlei relevante Literatur über Schaft – Kopf Probleme bekannt waren. Zumindest der Firma Zimmer sind die Probleme der von ihr hergestellten Harris-Galante Hüftprothese bekannt. Somit hätte sie diese Erkenntnisse zum Zeitpunkt der Markteinführung der Durom-Metasul-LDH-Hüftprothese 2003 auch berücksichtigen müssen. Weiterlesen..
Korrosion an der Schaft – Kopf – Verbindung der Harris – Galante Hüftprothese der Firma Zimmer, Warsaw, IN

Das Unternehmen Zimmer hatte vor der Einführung der modularen Durom – Metasul – LDH Hüftprothese Kenntnis von Problemen mit der Schaft – Kopf – Verbindung und war an der Erforschung der Ursachen maßgeblich beteiligt.

1996 untersucht das Forschungslabor von Zimmer die Auswirkungen, die Herstellungstoleranzen auf die Mikrobewegungen an der Konusverbindung haben: Shareef N, Levine D. Effect of manufacturing tolerances on the micromotion at the Morse taper interface in modular hip implants using the finite element technique. Biomaterials. 1996; 17:623–630
Schon Anfang der 90 Jahren des letzten Jahrhunderts häufen sich die Veröffentlichungen, die bei Harris-Galante Hüftprothesen (Zimmer, Warsaw) Korrosion an der Konusverbindung Schaft – Kopf beschreiben. Die folgende Auflistung ist keineswegs vollständig.

  • Collier JP, Surprenant VA, Jensen RE, Mayor MB. Corrosion at the interface of cobalt-alloy heads on titanium-alloy stems. Clin Orthop Relat Res. 1991; 271:305–312
    Von 30 revidierten Ti-Schaft/CoCr-Kopf Prothesen (Harris-Galante) zeigten 56% Korrosion am Übergang Schaft – Kopf. Co/Co und Ti/Ti zeigten keine Korrosion.
    The corrosion observed in this study required a dissimilar metal combination, breakdown of the passive film, and body fluids in the taper region between the two components. The narrower the crevice between the cobalt-alloy head and titanium-alloy stem, the more rapidly the corrosion develops; crevices on the order of 2.5 µm provide the optimal corrosion environment.6 In some cases it may be possible that the interface between cobalt-alloy head and titaniumalloy neck will be so tightly fitted that it will eliminate the possibility of aqueous intrusion. If so, the initial corrosion will occur at the distal lip of the femoral head where it mates to the tapered titanium neck. This was observed in nine devices. Additionally, any micromotion between head and neck caused by poor tolerancing, improper fixation of the head to the taper, or corrosion of the taper may result in fretting that would rapidly accelerate the overall process.
  • Harry A. McKellop, PhD, Augusto Sarmiento, MD, William Brien, MD, and Sang Hyun Park, PhD, Interface Corrosion of a Modular Head Total Hip Prosthesis. J Arthroplasty, 1992, 7(3):291-294
    Bericht von einem Fall bei dem eine Harris-Galante Prothese der Firma Zimmer revidiert wurde. Der Kopf war so fest mit dem Schaft verbunden, dass er heruntergeschlagen werden musste. Die Kontaktflächen von Schaft und Kopf zeigten deutliche Korrosion. Um eine stabile Schaft-Kopf Verbindung zu erzielen fordern sie passgenaue Komponenten mit kleinen Toleranzen um die Mikrobewegung und Korrosion zu verringern.
    “To minimize deterioration of the Morse taper junction, great care must be taken that the devices are manufactured with appropriate tolerances to minimize crevices and micromotion between the ball and stem. In addition, it is essential to remove contaminant such as blood, tissue, or bone fragments from the taper interface. The ball should be firmly impacted onto the neck, following the instructions provided by the manufacturer. Patients with modular prostheses should be monitored for evidence of loosening of the ball on the stem and for radiographic evidence of osteolysis caused by metallic corrosion products from the Morse taper connection, so that the clinical significance of this problem may be assessed”.

 

  • Collier JP, Mayor MB, Jensen RE, Surprenant VA, Surprenant HP, McNamar JL, Belec L. Mechanisms of failure of modular prostheses. Clin Orthop Relat Res. 1992; 285:129–139.
    23 von 25 korrodierten Schaft – Kopf Übergänge waren Harris-Galante und Bias Prothesen, hergestellt von Zimmer
    All modular connections of femoral and acetabular components are at risk for dissociation and fretting; therefor clever design and precision machining are necessary to produce protheses in which the benefits of modularity exeed the risks
  • Collier JP, Surprenant VA, Jensen RE, Mayor MB, Surprenant HP. Corrosion between the components of modular femoral hip prostheses. J Bone Joint Surg Br. 1992; 74:511–517.
    Tabelle mit Auflistung des Korrosiongrades in % zu 22 Harris-Galante Prothesen. Es wird zeitabhängige Korrosion festgestellt.
    We studied the tapered interface between the bead and tbe neck of 139 modular femoral components of hip prostbeses which had been removed for a variety of reasons. In 91 the same alloy had been used for the head and the stem; none of them showed evidence of corrosion. In contrast, there was definite corrosion in 25 of the 48 prostheses in which the stem was of titanium alloy and the head of cobalt-chrome. This corrosion was time-dependent: no specimens were corroded after less than nine months in the body, but all which had been in place for more than 40 months were damaged.
  • Gilbert JL, Buckley CA, Jacobs JJ. In vivo corrosion of modular hip prosthesis components in mixed and similar metal combinations. The effect of crevice, stress, motion, and alloy coupling. J Biomed Mater Res. 1993; 27:1533–1544.
    Mit Unterstützung und folgenden Prothesen von Zimmer wird eine Untersuchung durchgeführt: 90 Harris-Galante, 17 Bias, 19 Precoat.
    In this study, evidence of corrosion in both mixed metal and same-metal prostheses was presented. The corrosion processes observed are varied and complex. It is not clear if some of the mechanisms of corrosion are correlated with the duration of implantation or if perhaps some mechanisms are just more severe cases of others (e.g., intergranular vs. etching). However, several factors appear to be playing a dominant role and are outlined below.
    It is hypothesized that the restricted crevice environment, coupled with high cyclic stresses which cause repeated fracture of the passive oxide films in the taper, result in an unstable electrochemical environment within the crevice for both the cobalt alloy and Ti-alloy passive films. The passivity of these alloys is subsequently lost and active attack of the taper results. Also, the repeated fracturing of the passive films will result in large amounts of corrosion products being formed. This corrosion and particulate accumulation could result in loss of mechanical integrity of the implants in vim, create particles for third body wear, and release particles into the surrounding tissues.
  • Lieberman JR, Rimnac CM, Garvin KL, Klein RW, Salvati EA. An analysis of the head-neck taper interface in retrieved hip prostheses. Clin Orthop Relat Res. 1994; 300:162–167.
    8 Harris-Galante und 2 Bias Explantate wurden untersucht. Es wird beschrieben wie eine richtige Schaft – Kopf – Verbindung aussehen muss.
    (crevice corrosion was noted in one taper interface and there was fretting in two other tapers) Two of the ten Zimmer prostheses were noted to have experienced fretting characterized by loss of machining marks in the cobalt alloy head and the titanium alloy taper. In one prosthesis that had been implanted for 18 months, the fretting involved 75% of the surface area of the head and 17% of the surface area of the taper. The other prosthesis was revised after 59 months and fretting was noted in 75% of the surface area of the head and 29% of the femoral taper (Figs. 2A and 2B). Additionally, in another prosthesis that had been implanted for 43 months, pitting of the femoral head and taper consistent with crevice corrosion was noted.
    12 Triad Implantate (J&J) die in der Firma mittels eines Pressverfahrens zusammen gesetzt und mit Silikon versiegelt wurden zeigten keine Korrosion.
    The results of this retrieval analysis suggest that improving the tolerances of the mating surfaces may be an important factor in preventing corrosion. This would not only increase the forces that are necessary to debond the mating surfaces, but it would also decrease corrosion by reducing micromotion and fluid at the taper interface.
  • Jacobs JJ, Urban RM, Gilbert JL, Skipor AK, Black J, Jasty M, Galante JO. Local and distant products from modularity. Clin Orthop Relat Res. 1995; 319:94-105.
    Mit Unterstützung und den Prothesen Harris – Galante und Precoat von Zimmer, Warsaw, IN
    In summary, this study has shown that solid products of corrosion at the head and neck taper interface can be observed adherent to the implant and within the periprosthetic tissues in association with a large variety of modular femoral stems of 3 material combinations (CoCr/CoCr, CoCr/Ti6A14V, and Al,O,/CoCr). These particles may play a pathogenic role in osteolysis and aseptic loosening either by accelerating articular wear via a 3-body mechanism”] or by direct activation of macrophages that, in turn, stimulate osteoclastic bone resorption. In addition, soluble corrosion products from these taper interfaces are transported in the bloodstream with the possibility of accumulation in remote organs. Presently, the potential for metabolic, immunologic, and oncogenic toxicity is not known. Although the authors believe that it is premature to eliminate femoral implants with head and neck modularity from the surgeon’s armamentarium, improvements in fretting corrosion resistance are required to ensure the durability and safety of these devices.
    In this study, the local and distant distribution of solid and soluble products of corrosion from the head and neck junction of modular femoral total hip prosthetic components were characterized. Particulate corrosion products from retrieved implants and surrounding tissues were analyzed. Serum transport and urinary excretion of metal was measured in correlation with the degree of corrosion at the head and neck junction. Particles of metal oxides, metal chlorides, and chromium phosphate corrosion products were identified on implants of 10 designs from 6 manufacturers. The most abundant solid corrosion product on the implant and within the periprosthetic tissues (size range, 4-200 micrometers) was an amorphous chromium orthophosphate hydrate-rich material. Serum cobalt and urine chromium concentrations were elevated significantly in patients with implants that had moderate to severe corrosion in comparison with those with no to mild corrosion. Solid corrosion products from modular femoral stems may accelerate articular wear via a 3-body mechanism. Phagocytosable particles of these corrosion products may stimulate macrophage-mediated periprosthetic bone loss. Systemic dissemination of metallic corrosion products raises the issue of systemic toxicity; however, no overt evidence of metal toxicity was observed in this study.
  • Salvati EA, Lieberman JR, Huk OL, Evans BG. Complications of femoral and acetabular modularity. Clin Orthop Relat Res. 1995; 319:85-93.
    10 Revisionsimplantate von Zimmer. (Ti-schaft/CoCr-kopf: Harris-Galante) wurden untersucht und z. T. abgebildet. Hinweise zum Fügen der Schaft – Kopf – Verbindung werden gegeben und Forderungen an die Hersteller formuliert.
    Three of the 10 Zimmer implants (average time of implantation, 34 months) with a cobalt alloy head and a titanium stem had fretting or crevice corrosion. This fretting was characterized by loss of machining marks at the head-taper interfaces. In 1 prosthesis that had been implanted for 18 months, the fretting involved 75% of the surface area of the head and 29% of the femoral taper (Fig 1). In another prosthesis that had been implanted for 59 months, fretting was seen in 75% of the surface area of the head and 29% of the surface area of the taper. Pitting of the femoral head and taper interface consistent with crevice corrosion was seen in another prosthesis that had been implanted for 43 months (Fig 2).
    Hinweise zum Fügen der Schaft – Kopf – Verbindung:
    Surgeons should be aware of the importance of assembling the taper lock under ideal conditions. The interface must be dry without the interposition of blood or fluids and, as observed in 1 of the pull-off tests, fragments of acrylic cement (Fig 5). Adequate blows with the hammer to ensure proper mechanical lock following the manufacturer’s instructions are mandatory. There are significant differences in the design characteristics of the different modular heads among manufacturers. Mixing heads and tapers from different manufacturers is contraindicated.
    Forderungen an die Hersteller:
    Taper locks for femoral components and locking mechanisms for the polyethylene liner and metallic cup must be designed to avoid the production of particulate debris.
  • Jacobs JJ, Skipor AK, Patterson LM, Hallab NJ, Paprosky WG, Black J, Galante JO. Metal release in patients who have had a primary total hip arthroplasty. A prospective, controlled, longitudinal study. J Bone Joint Surg Am. 1998; 80:1447–1458.
    Untersuchung von Patienten mit Zimmer Harris -Galante Implantaten in Gruppe 3 ergibt nach 36 Monaten eine Zunahme der Konzentration von Cobalt und Chrom im Blutserum.
    The results of our study showed that, thirty-six months postoperatively, patients who have a well functioning prosthesis with components containing titanium have as much as a threefold increase in the concentration of titanium in the serum and those who have a well functioning prosthesis with cobalt-alloy components have as much as a fivefold and an eightfold increase in the concentrations of chromium in the serum and urine, respectively.
    Die Autoren kommen zu dem Ergebnis, dass die modulare Schaft-Kopf – Verbindung die Ursache sein muss:
    The predominant source of the disseminated chromium-degradation products is probably the modular head-neck junction and may be a function of the geometry of the coupling. Passive dissolution of extensively porous-coated cobalt-alloy stems was not found to be a dominant mode of metal release.
  • Goldberg JR, Gilbert JL. In vitro corrosion testing of modular hip tapers. J Biomed Mater Res B Appl Biomater. 2003; 64B:78-93.
    Prothesen von Zimmer zu Testzwecken. In der Zusammenfassung die Forderung:
    Proper seating of the head onto the neck
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