“…As previously reported, 12,13 we have confirmed that a constant cortical spur was localised at the lower part of the femoral metaphysis adjacent to the medial endosteal line. Sometimes this spur is enlarged and impedes reaming and positioning of the stem.…”
Section: Clinical Relevance: Anticipation Of Intra-operative Difficulsupporting
confidence: 89%
“…The femoral canal is always prepared with a curette before the reaming procedure. First, the cancellous bone in contact with the lateral cortical bone under the great trochanter is removed in order to prepare the site where the lateral flare of the stem would be received; and second, if a large internal calcar septum 12,13 is detected on the pre-operative CT scan, it is removed. The operators check the stem position with two parameters.…”
Pre-operative computerised three-dimensional planning was carried out in 223 patients undergoing total hip replacement with a cementless acetabular component and a cementless modular-neck femoral stem. Components were chosen which best restored leg length and femoral offset. The post-operative restoration of the anatomy was assessed by CT and compared with the pre-operative plan. The component implanted was the same as that planned in 86% of the hips for the acetabular implant, 94% for the stem, and 93% for the neck-shaft angle. The rotational centre of the hip was restored with a mean accuracy of 0.73 mm (SD 3.5) craniocaudally and 1.2 mm (SD 2) laterally. Limb length was restored with a mean accuracy of 0.3 mm (SD 3.3) and femoral offset with a mean accuracy of 0.8 mm (SD 3.1). This method appears to offer high accuracy in hip reconstruction as the difficulties likely to be encountered when restoring the anatomy can be anticipated and solved pre-operatively by optimising the selection of implants. Modularity of the femoral neck helped to restore the femoral offset and limb length.
“…As previously reported, 12,13 we have confirmed that a constant cortical spur was localised at the lower part of the femoral metaphysis adjacent to the medial endosteal line. Sometimes this spur is enlarged and impedes reaming and positioning of the stem.…”
Section: Clinical Relevance: Anticipation Of Intra-operative Difficulsupporting
confidence: 89%
“…The femoral canal is always prepared with a curette before the reaming procedure. First, the cancellous bone in contact with the lateral cortical bone under the great trochanter is removed in order to prepare the site where the lateral flare of the stem would be received; and second, if a large internal calcar septum 12,13 is detected on the pre-operative CT scan, it is removed. The operators check the stem position with two parameters.…”
Pre-operative computerised three-dimensional planning was carried out in 223 patients undergoing total hip replacement with a cementless acetabular component and a cementless modular-neck femoral stem. Components were chosen which best restored leg length and femoral offset. The post-operative restoration of the anatomy was assessed by CT and compared with the pre-operative plan. The component implanted was the same as that planned in 86% of the hips for the acetabular implant, 94% for the stem, and 93% for the neck-shaft angle. The rotational centre of the hip was restored with a mean accuracy of 0.73 mm (SD 3.5) craniocaudally and 1.2 mm (SD 2) laterally. Limb length was restored with a mean accuracy of 0.3 mm (SD 3.3) and femoral offset with a mean accuracy of 0.8 mm (SD 3.1). This method appears to offer high accuracy in hip reconstruction as the difficulties likely to be encountered when restoring the anatomy can be anticipated and solved pre-operatively by optimising the selection of implants. Modularity of the femoral neck helped to restore the femoral offset and limb length.
“…So, we used a 0.625 mm slice thickness, 512 3 512 image matrix and a high-resolution image reconstruction mode to obtain sharp cancellous and cortical bone structures for exact thresholding. As an anatomically defined border does not exist between the femoral calcar and the surrounding cancellous bone, the dense spur protruding from the femoral inner cortical wall branches out into trabeculae and merges gradually with the surrounding cancellous bone (Decking et al, 2003). The dimensions of the septum recorded in our study may consequently be considered as rough measurements of an irregular structure, representing only the dense cortical stem of the femoral calcar.…”
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.
“…Thus, we always prepared the proximal femoral canal with a curette before rasping. First we removed cancellous bone in contact with the lateral cortex under the greater trochanter to prepare the place where the lateral flare of the stem was located, and second, we removed any excessive femoral “internal calcar septum” [10] (the internal vertical plate of condensed trabecular bone constituting the anatomic calcar).…”
BackgroundProximal cementless fixation using anatomic stems reportedly increases femoral fit and avoids stress-shielding. However, thigh pain was reported with the early stem designs. Therefore, a new anatomic cementless stem design was based on an average three-dimensional metaphyseal femoral shape. However, it is unclear whether this stem reduces the incidence of thigh pain.Questions/purposesWe asked whether this stem design was associated with a low incidence of thigh pain and provided durable fixation and high function.MethodsOne hundred seventy-one patients (176 THAs) who had the anatomic proximal hydroxyapatite-coated stem implanted were reviewed. Eleven (6%) patients were lost to followup and 34 (20%) died without revision surgery. We used the Harris hip score (HHS) to assess pain and function. We evaluated femoral stem fixation and stability with the score of Engh et al. and also calculated a 10-year survival analysis. We assessed 126 patients (131 hips) at a mean followup of 10 years (range, 8–11 years)ResultsAt last followup, two patients described slight thigh pain that did not limit their physical activities. All stems appeared radiographically stable and one stem was graded nonintegrated but stable. Five patients had revision surgery: one on the femoral side (for posttraumatic fracture) and four on the acetabular side. Considering stem revision for aseptic loosening as the end point, survivorship was 100% (range, 95.4%–99.9%) at 10 years.ConclusionThis anatomic cementless design using only metaphyseal fixation with a wide mediolateral flare, a sagittal curvature, and torsion, allowed durable proximal stem stability and fixation.Level of EvidenceLevel IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
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