The Significance of Posterior Comminution in Femoral Neck Fractures

Scheck, Max

doi:10.1097/00003086-198010000-00014

Cited by 56 publications

(31 citation statements)

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“…As a consequence, since falls preferentially subject the primary tensile trabeculae to increased stresses, we suggest that with osteoporosis there is a disproportionate increase in traumatic (fall) fracture risk over spontaneous (gait) fracture risk. Further, the suggested failure mechanism of crushing of the primm-y tensile group and tensile failure of the inferomedial neck in response to a fall is supported by the clinical observation that a majority of subcapital fractures are marked by comminution of the posterior/ superior cortex with concomitant posterior dislocation of the femoral head [40].…”

Section: Discussionmentioning

confidence: 92%

Stress distributions within the proximal femur during gait and falls: Implications for osteoporotic fracture

1995

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The rates of fracture at sites with different relative amounts of cortical and trabecular bone (hip, spine, distal radius) have been used to make inferences about the pathomechanics of bone loss and the existence of type I and type II osteoporosis. However, fracture risk is directly related to the ratio of tissue stress to tissue strength, which in turn is dependent not only on tissue composition but also tissue geometry and the direction and magnitude of loading. These three elements determine how the load is distributed within the tissue. As a result, assumptions on the relative structural importance of cortical and trabecular bone, and how these tissues are affected by bone loss, can be inaccurate if based on regional tissue composition and bone density alone. To investigate the structural significance of cortical and trabecular bone in the proximal femur, and how it is affected by bone loss, we determined the stress distributions in a normal and osteoporotic femur resulting from loadings representing: (1) gait; and (2) a fall to the side with impact onto the greater trochanter. A three-dimensional finite element model was generated based on a representative femur selected from a large database of femoral geometries. Stresses were analyzed throughout the femoral neck and intertrochanteric regions. We found that the percentage of total load supported by cortical and trabecular bone was approximately constant for all load cases but differed depending on location. Cortical bone carried 30% of the load at the subcapital region, 50% at the mid-neck, 96% at the base of the neck and 80% at the intertrochanteric region. These values differ from the widely held assumption that cortical bone carries 75% of the load in the femoral neck and 50% of the load at the intertrochanteric region. During gait, the principal stresses were concentrated within the primary compressive system of trabeculae and in the cortical bone of the intertrochanteric region. In contrast, during a fall, the trabecular stresses were concentrated within the primary tensile system of trabeculae with a peak magnitude 4.3 times that present during gait. While the distribution of stress for the osteoporotic femur was similar to the normal, the magnitude of peak stress was increased by between 33% and 45%. These data call into question several assumptions which serve as the basis for theories on the pathomechanics of osteoporosis. In addition, we expect that the insight provided by this analysis will result in the improved development and interpretation of non-invasive techniques for the quantification of in vivo hip fracture risk.

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Section: Discussionmentioning

confidence: 92%

Stress distributions within the proximal femur during gait and falls: Implications for osteoporotic fracture

1995

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“…A major comminution of the posterior aspect of the femoral neck in Garden Stage III and IV fractures occurs in ϳ70% of cases and is an important determinant of insecure fracture fixation. 56 The clinical hip fracture studies that have been published agree only on the point that there is a lack of agreement among surgeons on which method to use. Bhandari et al 48 performed an international survey and found that for unstable femoral neck fractures, surgeons prefer internal fixation for younger patients and arthroplasty for elderly.…”

Section: Discussionmentioning

confidence: 99%

A Comparative Biomechanical Analysis of Fixation Devices for Unstable Femoral Neck Fractures: The Intertan Versus Cannulated Screws or a Dynamic Hip Screw

Rupprecht

Großterlinden

Ruecker

et al. 2011

Journal of Trauma: Injury, Infection &Amp; Critical Care

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Our results suggest that (1) none of the tested devices restore a comparable mechanical strength in the fractured specimens compared with the intact femurs, and (2) the "IT" possesses some biomechanical benefits for internal fixation of unstable femoral neck fractures compared with DHS and CS. Because the IT constructs failed with an inferior femoral neck fracture, complicating the mandatory anchorage of a prosthetic stem in a revision operation, more biomechanical experiments using the IT in the presence of a posterior comminution defect are required, along with clinical outcome studies.

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“…In osteoporotic bone, it is hard to imagine a femoral neck fracture without comminution. Posterior comminution has been found to occur in 35-100% of fractures of the femoral neck (Scheck 1980). It seems very likely that the degree of comminution varies.…”

Section: Discussionmentioning

confidence: 99%

Low interobserver reliability of radiographic signs predicting healing disturbance in displaced intracapsular fracture of the femoral neck

Bjørgul

Reikerås

2002

Acta Orthopaedica Scandinavica

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The Significance of Posterior Comminution in Femoral Neck Fractures

Cited by 56 publications

References 0 publications

Stress distributions within the proximal femur during gait and falls: Implications for osteoporotic fracture

Stress distributions within the proximal femur during gait and falls: Implications for osteoporotic fracture

A Comparative Biomechanical Analysis of Fixation Devices for Unstable Femoral Neck Fractures: The Intertan Versus Cannulated Screws or a Dynamic Hip Screw

Low interobserver reliability of radiographic signs predicting healing disturbance in displaced intracapsular fracture of the femoral neck

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