The histology around the cemented Müller straight stem

Clauss, Martin; Ilchmann, Thomas; Zimmermann, Peter; Ochsner, P. E.

doi:10.1302/0301-620x.92b11.25342

Cited by 17 publications

(17 citation statements)

References 34 publications

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“…Implants were cemented line-to-line with the final broach (El Masri et al 2010), but in contrast to other canal-filling implants like the Kerboul stem, the medullary canal was prepared with broaches that did not remove cancellous bone in the sagittal plane (Kerboul 1987, Clauss et al 2010). All stems were cemented using a second-generation cementing technique (distal plug, cement syringe, no vacuum-mixing, no jet lavage, and no proximal sealing) with Sulfix-6 bone cement without antibiotics (low viscosity, Zimmer).…”

Section: Methodsmentioning

confidence: 99%

“…All of them have shown reliable long-term survival (Fowler et al 1988, Howie et al 1998, Herberts and Malchau 2000, Morscher et al 2005, Buckwalter et al 2006, Hamadouche et al 2008, Clauss et al 2009). The Müller straight stem (MSS; Zimmer, Winterthur, Switzerland) was designed according to the shape-closed concept in order to achieve a press-fit fixation in the anterior-posterior plane with a self-centering effect (Clauss et al 2010). The original MSS was made out of forged CoNiCrMo (Co).…”

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confidence: 99%

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Risk factors for aseptic loosening of Müller-type straight stems

Clauss¹,

Gersbach²,

Butscher³

et al. 2013

Acta Orthopaedica

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Background and purpose Even small differences in design variables for the femoral stem may influence the outcome of a hip arthroplasty. We performed a risk factor analysis for aseptic loosening of 4 different versions of cemented Müller-type straight stems with special emphasis on design modifications (2 shapes, MSS or SL, and 2 materials, CoNiCrMo (Co) or Ti-6Al-7Nb (Ti)).Methods We investigated 828 total hip replacements, which were followed prospectively in our in-house register. All stems were operated in the same setup, using Sulfix-6 bone cement and a second-generation cementing technique. Demographic and design-specific risk factors were analyzed using an adjusted Cox regression model.Results The 4 versions showed marked differences in 15-year stem survival with aseptic loosening as the endpoint: 94% (95% CI: 89–99) for MSS Co, 83% (CI: 75–91) for SL Co, 81% (CI: 76–87) for MSS Ti and 63% (CI: 56–71) for SL Ti. Cox regression analysis showed a relative risk (RR) for aseptic loosening of 3 (CI: 2–5) for stems made of Ti and of 2 (CI: 1–2) for the SL design. The RR for aseptic stem loosening increased to 8 (CI: 4–15) when comparing the most and the least successful designs (MSS Co and SL Ti).Interpretation Cemented Müller-type straight stems should be MSS-shaped and made of a material with high flexural strength (e.g. cobalt-chrome). The surface finish should be polished (Ra < 0.4 µm). These technical aspects combined with modern cementing techniques would improve the survival of Müller-type straight stems. This may be true for all types of cemented stems.

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Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Risk factors for aseptic loosening of Müller-type straight stems

Clauss¹,

Gersbach²,

Butscher³

et al. 2013

Acta Orthopaedica

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“…The Müller CDH stem was developed for hips with altered anatomy showing small femora, or dysplastic hips presenting an increased CCD angle with a small head, allowing for a wedge-type stem with additional cement fixation. It follows the same cementing philosophy as the original Müller straight stem, however, with extended possible indications [ 18 , 31 ]. For cemented Müller straight stems, Clauss et al [ 13 ] have shown osteolysis to occur mainly in the Gruen zones 6 and 7 with debonding first appearing superolaterally, which is in accordance to the radiological findings of the Müller CDH straight stem.…”

Section: Discussionmentioning

confidence: 99%

“…Subsidence was defined as being an increase of radiolucency between the shoulder of the prosthesis and proximal cement in Gruen zone 1 [ 12 ]. Cortical atrophy of the femur was defined as being a longitudinal thinning of the femoral cortex due to intracortical porosis, without any measurable changes of the diameter of the femur [ 18 ]. Debonding, osteolysis, and cortical atrophy of the femur were evaluated in the Gruen zones [ 19 ].…”

Section: Methodsmentioning

confidence: 99%

Long-term survival of the cemented Müller CDH stem: a minimum follow-up of 10 years

Salentiny

Zwicky

Ochsner

et al. 2018

Arch Orthop Trauma Surg

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IntroductionTotal hip arthroplasty in patients with altered anatomy of the hip and femur, such as in congenital dysplasia of the hip, is challenging and often requires specially designed stems. Müller straight stems have shown excellent long-term results; however, long-term data on the analogous cemented Müller CDH stem are still missing. The aim of this study was to analyze long-term survival, identify potential risk factors for aseptic loosening, and analyze radiological outcome of the cemented Müller CDH stems.Materials and methodsBetween 01/1985 and 06/2005, 95 Müller CDH stems (Zimmer, Winterthur, Switzerland) made up of 3 different materials were cemented using 2 different bone cements: 38 of stainless steel/high-viscosity cement, 31 of a cobalt-chrome-based alloy (CoCr)/low-viscosity cement, and 26 of a titanium-based alloy (Ti)/low-viscosity cement. All patients had a prospective clinical and radiological follow-up according to the standards of our institution. The cumulative incidence for revision of the stem was calculated using a competing risk model. To identify demographic and implant-related risk factors for aseptic loosening of the stem, a multivariate regression model for competing risks was performed.ResultsThe cumulative risk of revision at 15 years was 12.5% (95% CI 6.6–20.5%) for aseptic loosening of the stem as endpoint, with marked differences for the various stem materials used: stainless steel 2.7% (0.2–12.3%), CoCr 12.9% (4.0–27.3%), and Ti 24.5% (9.6–43.1%). Regression modeling revealed that Ti stems in combination with low-viscosity cement (HR 10.2) and implantation with an axis deviation greater than 3° (HR 3.8) are risk factors for aseptic loosening.ConclusionsLong-term survival of the cemented Müller CDH stem is comparable to other Müller-type straight stems and uncemented implants. Similar to the original Ti Müller straight stem, the Ti Müller CDH stem also showed an increased risk for aseptic loosening and should, therefore, no longer be used.

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“…Unfortunately, the amount of quantitative mechanical data of postmortem cement-bone interface specimens is, in contrast to lab-prepared data, also limited (Miller et al, 2011; Mann et al, 2010; Miller et al, 2010). In the past, studies to post-mortem cement-bone interfaces mainly focused on the histology rather than the mechanical behavior of the interface (Clauss et al, 2010; Bishop et al, 2009; Schmalzried et al, 1993; Jasty et al, 1991). Finally, the FEA models used in this study do not directly match the geometry of the postmortem specimens as a result of the mirroring.…”

Section: Discussionmentioning

confidence: 99%

Morphology based cohesive zone modeling of the cement–bone interface from postmortem retrievals

Waanders

Janssen

Mann

2011

Journal of the Mechanical Behavior of Biomedical Materials

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In cemented total hip arthroplasty, the cement-bone interface can be considerably degenerated after less than one year in-vivo service; this makes the interface much weaker relative to the direct post-operative situation. It is, however, still unknown how these degenerated interfaces behave under mixed-mode loading and how this is related to the morphology of the interface. In this study, we used a finite element approach to analyze the mixed-mode response of the cement-bone interface taken from postmortem retrievals and we investigated whether it was feasible to generate a fully elastic and a failure cohesive model based on only morphological input parameters. Computed tomography-based finite element analysis models of the postmortem cement-bone interface were generated and the interface morphology was determined. The models were loaded until failure in multiple directions by allowing cracking of the bone and cement components and including periodic boundary conditions. The resulting stiffness was related to the interface morphology. A closed form mixed-mode cohesive model that included failure was determined and related to the interface morphology. The responses of the finite element simulations compare satisfactorily with experimental observations, albeit the magnitude of the strength and stiffness are somewhat overestimated. Surprisingly, the finite element simulations predict no failure under shear loading and a considerable normal compression is generated which prevents dilation of the interface. The obtained mixed-mode stiffness response could subsequently be related to the interface morphology and subsequently be formulated into an elastic cohesive zone model. Finally, the acquired data could be used as an input for a cohesive model that also includes interface failure.

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The histology around the cemented Müller straight stem

Cited by 17 publications

References 34 publications

Risk factors for aseptic loosening of Müller-type straight stems

Risk factors for aseptic loosening of Müller-type straight stems

Long-term survival of the cemented Müller CDH stem: a minimum follow-up of 10 years

Morphology based cohesive zone modeling of the cement–bone interface from postmortem retrievals

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