Micromotion, Fit, and Fill of Custom Made Femoral Stems Designed With an Automated Process

Dujardin, F.; Mollard, Régis; Toupin, Jean; Coblentz, A.; Thomine, J M

doi:10.1097/00003086-199604000-00034

Cited by 37 publications

(24 citation statements)

References 19 publications

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“…In the same way, the femoral calcar is located in an anatomical region essential for the support and primary stability of cementless total hip replacement femoral stems. Callaghan et al (1992) and Dujardin et al (1996) demonstrated that fit and fill of stems in the metaphyseal region correlated with the initial rotational and vertical stability of the implants. Nunn et al (1989) showed that rotational stability of the stem is significantly increased by cortical contact between the stem and the femoral neck.…”

Section: Discussionmentioning

confidence: 97%

The femoral calcar: A computed tomography anatomical study

et al. 2011

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The femoral calcar is a dense internal septum reaching from the femoral neck to the distal part of the lesser trochanter. Our study aimed at providing an exhaustive radio-anatomical description of this structure. One hundred pelvic computed tomography examinations were retrospectively selected to bilaterally evaluate the shape, dimensions, and density of the femoral calcar. Then, its relation to the femoral cavity was assessed by recording the dimensions of the medullary canal at the level of the greatest length of the spur. The femoral calcar exhibited a variable shape classified as ridge-type 17% (34/200), spur-type 66.5% (133/200), and septum-type 16.5% (33/200). Its mean dimensions were: height = 33.03 mm (20-46), length = 9.94 mm (5-16), and thickness = 2.71 mm (1-4). These dimensions were positively correlated to the height and weight of the individuals (P < 0.001) and were higher in males (P < 0.001). Its mean density was 788.5 Hounsfield units (530-1,200). The longest oblique and anteroposterior diameters of the femoral cavity were respectively 38.74 mm (28-51) and 22.04 mm (17-27). The femoral cavity dimensions were positively correlated to the height and weight of the individuals (P < 0.001), to the femoral calcar dimensions (P < 0.001) and were higher in males (P < 0.001). The femoral calcar was constantly identified as a vertical plate of compact bone exhibiting a consistent anatomical pattern, which suggests a significant mechanical function within the upper femur. Our results may lead to a greater understanding of the hip fracture patterns and to alternative designs for hip arthroplasties.

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Section: Discussionmentioning

confidence: 97%

The femoral calcar: A computed tomography anatomical study

et al. 2011

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“…Clinical researches revealed that failures of cementless THA arose mainly from the micromotion of the implant and inadequate femoral canal filling and apposition between bone and prosthesis (Amstutz et al, 1991;Bargar, 1989;Dujardin et al, 1996;Walker et al, 2000). The mechanical strength between the bone and prosthesis interface is positively related to bony ingrowth into the implants.…”

Section: Introductionmentioning

confidence: 99%

The dimensional accuracy of preparation of femoral cavity in cementless total hip arthroplasty

Hahne

Hassenpflug

2004

J. Zheijang Univ.-Sci.

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Abstract:Objective: To observe the accuracy of femoral preparation and the position of the cementless prosthesis in femoral cavity, and to compare the results between the computer-assisted surgical group (CASPAR) and the conventional group. Methods: Ten femoral components were implanted either manually or by CASPAR in cadaver femurs. The specimens were cut to 3 mm thick slices. Microradiograms of every slice were sent to a computer for analysis with special software (IDL). The gaps and the medullary cavities between component and bone, the direct bone contact area of the implant surface, the gap width and the percentage of gap and bone contact area were measured in every slice. Results: In the proximal implant coated with HA of the CASPAR group, the average percentage of bone contact reached 93.2% (ranging from 87.6% to 99.7%); the average gap percentage was 2.9% (ranging from 0.3% to 7.8%); the maximum gap width was 0.81 mm and the average gap width was only 0.20 mm. While in the conventional group, the average percentage of bone contact reached 60.1% (ranging from 49.2% to 70.4%); the average gap percentage was 32.8% (ranging from 25.1% to 39.9%); the maximum gap width was 2.97 mm and the average gap width was 0.77 mm. The average gap around the implant in the CASPAR group was only 9% of that in the manual group; the maximum and average gap widths were only about 26% of those in the manual group. On the other hand, the CASPAR group showed 33% higher bone contact than the manual group. Conclusion: With the use of robotics-assisted system, significant progress can be achieved for femoral preparation in total hip arthroplasty.

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“…In experimental studies, Callaghan et al (1992) and Dujardin et al (1996) showed that fit and fill of stems in the metaphyseal region correlated with the initial rotational and vertical stability of the implants. Nunn et al (1989) found that rotational stability of the stem is significantly increased by cortical contact between the stem and the femoral neck.…”

mentioning

confidence: 99%