The effect of calcar contact on femoral component micromovement. A mechanical study.

Markolf, Keith L.; Hc, Amstutz; Hirschowitz, D.

doi:10.2106/00004623-198062080-00011

Cited by 84 publications

(21 citation statements)

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“…The absence of a collar is another design feature of relevance. Even though the use of a collar may increase the axial compression to the bone [5], it may impede the wedging effect of the lateral flare [18]. Its value as an additional feature to maximize prosthesis-bone contact in the primary setting is secondary to the stabilizing effect imposed by the extended proximal geometry of the implant [17] and the collar, therefore, is not a feature of the design of this stem.…”

Section: Discussionmentioning

confidence: 99%

Promising mid-term results of total hip arthroplasties using an uncemented lateral-flare hip prosthesis: a clinical and radiographic study

Leali

Fetto

2007

International Orthopaedics (SICO

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The clinical results after total hip replacements using noncemented stems have shown considerable variability over the years; the design and characteristics of the implant seemed to play a role in explaining this fact. The purpose of this paper is to report the clinical, radiographic and densitometry results of total hip arthroplasties using a stem designed for noncemented implantation and to engage and load the femur proximally. Fifty-eight consecutive patients (62 hips) followed for an average of 4.3 years (range 36-70 months) were clinically and radiographically followed up at three weeks, three months, six months, one year, and yearly thereafter. The average pre-operative Harris hip score was 49 increasing to 98 at the latest follow-up. There were no cases of aseptic or septic loosening. The average subsidence at three years was 0.45 mm (SD±0.36 mm). Radiographically all hips were classified as stable, and evident changes compatible with new bone apposition were observed in 64% of the cases. The extended proximal geometry of the device seems to favour initial and secondary stability as reflected by the low subsidence values over time. The maintenance of periprosthetic bone stock and the absence of stress shielding can be explained by the predominantly proximal loading pattern of the stem.Résumé Les résultats cliniques des arthroplasties totales de hanche utilisant des tiges non-cimentées ont été très variables au cours des années, les caractéristiques de l'implant semblant jouer un rôle important. Le but de ce travail est de rapporter les résultats cliniques et radiologiques d'arthroplasties avec une tige non-cimentée avec appui proximal. 58 patients consécutifs (62 hanches) suivi en moyenne pendant 4,3 ans (36 à 70 mois) étaient étudiés à 3 semaines, 3 mois, 6 mois, 1 an puis tous les ans. Le score moyen de Harris pré-opératoire était de 49, augmentant à 98 au dernier examen. Il n'y avait pas de descellement aseptique ou septique. L'enfoncement moyen à 3 ans était de 0,45 mm (SD 0,36 mm). Radiologiquement toutes les hanches étaient stables et des modifications compatibles avec une ostéoformation était visible dans 64% des cas. La géométrie proximale de la tige semble favoriser la stabilité initiale et secondaire comme le montre le faible enfoncement au fil du temps. La conservation du stock osseux et l'absence de déviation des contraintes peuvent s'expliquer par la mise en charge proximale de la prothès.

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Section: Discussionmentioning

confidence: 99%

Promising mid-term results of total hip arthroplasties using an uncemented lateral-flare hip prosthesis: a clinical and radiographic study

Leali

Fetto

2007

International Orthopaedics (SICO

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“…Therefore, many authors have performed studies of this topic, [5][6][7] and much effort has been devoted to improving the initial stability of cementless stems. [8][9][10][11][12][13][14][15] A new femoral component for hip arthroplasty, named the cemented-locked uncemented (CLU) stem, was developed using an innovative concept for initial fixation of the implant to the bone. The CLU prototype has a press-fit stem partially cemented by means of cement injected into two pockets that are machined in the stem in the lateral-proximal area.…”

Section: Introductionmentioning

confidence: 99%

Initial stability of a new hybrid fixation hip stem: Experimental measurement of implant-bone micromotion under torsional load in comparison with cemented and cementless stems

Baleani

Cristofolini

Toni

2000

J. Biomed. Mater. Res.

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A new hybrid fixation stem, named cemented-locked uncemented (CLU), for total hip arthroplasty was developed to achieve good initial stability. Primary stability is guaranteed by the cement which is injected into two pockets in the lateral area. This leaves a large surface available for long-term biologic fixation (direct bone attachment on implant). This study evaluates in vitro the initial stability of the CLU prototype under torsional load, in comparison with cemented and cementless stems. The results show that the CLU stem is very stable in simulated stair climbing. Its micromotions are comparable to those of a cemented prosthesis, and significantly less (80-90% lower) than those for a cementless stem. These findings confirm the optimal initial stability expected from the CLU prototype. This new design, which employs hybrid fixation, should improve bone formation on the implant and reduce the risk of stem loosening.

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“…In a normal hip joint, loads from the body are transmitted to the femoral head, then to the medial cortical bone of femoral neck towards the lesser trochanter, where they are distributed by the diaphyseal bone (Radin, 1980). The implantation of a cemented or cementless femoral stem produced a clear alteration of the physiological transmission of loads, as these are now passed through the prosthetic stem, in a centripetal way, from the central marrow cavity to the cortical bone (Marklof et al, 1980). These changes of the normal biomechanics of the hip bone leads to a phenomenon called adaptive remodeling (Huiskes et al, 1989), since bone has to adapt to the new biomechanical situation.…”

Section: Application To the Behaviour Of Hip Prosthesesmentioning

confidence: 99%

Finite element simulation. Applications in Orthopaedics and Traumatology

Herrera¹

2010

Finite Element Analysis

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The effect of calcar contact on femoral component micromovement. A mechanical study.

Cited by 84 publications

References 0 publications

Promising mid-term results of total hip arthroplasties using an uncemented lateral-flare hip prosthesis: a clinical and radiographic study

Promising mid-term results of total hip arthroplasties using an uncemented lateral-flare hip prosthesis: a clinical and radiographic study

Initial stability of a new hybrid fixation hip stem: Experimental measurement of implant-bone micromotion under torsional load in comparison with cemented and cementless stems

Finite element simulation. Applications in Orthopaedics and Traumatology

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