Three-Dimensional Morphology of the Distal Part of the Femur Viewed in Virtual Reality

Eckhoff, Donald G.; Dwyer, Thomas F.; Bach, Joel M.; Spitzer, Victor M.; Reinig, Karl D.

doi:10.2106/00004623-200100021-00010

Cited by 80 publications

(91 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A survey of the literature suggests there is morphologic variation in the femur and tibia between subpopulations based on race. For example, there appears to be a difference between white, black, and Asian populations in the degree of femoral anteversion [12]. Although our data show a difference between the CA and TEA for whites, we do not suggest the observation of a difference between the CA and TEA, or their relative orientation to mechanical axes, extends across all populations.…”

Section: Discussioncontrasting

confidence: 80%

“…Although it is difficult to say what is clinically significant based on a biomechanical study, in a concurrent clinical radiographic review published in the same paper, Hsu, et al [19] found a disturbing clinical correlation between increased implant malalignment and increasing lucent lines around the tibial components of otherwise successful implants at average 6 years followup. Other studies [15,20] Although previous work suggests the cylindrical axis (CA) is a better surrogate for the FEA [2,3,[8][9][10][11][12], there is no documentation in the literature regarding the relationship of either the TEA or CA to the femoral mechanical axis or the tibial mechanical axis. Because the goal of a contemporary TKA is to position the tibial component at a right angle to the tibial axis and the femoral component at a right angle to the femoral mechanical axis [15,19,20], it may be useful to know whether either axis being used as a surrogate is perpendicular to these longitudinal axes.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Cylindrical Axis, Not Epicondyles, Approximates Perpendicular to Knee Axes

Hancock

Winston

Bach

et al. 2013

Clinical Orthopaedics &Amp; Related Research

Self Cite

View full text Add to dashboard Cite

Background The transepicondylar axis (TEA) is often used as a surrogate for the flexion-extension axis, ie, the axis around which the tibia moves in space, because of a belief that both axes lie perpendicular to the mechanical axis. However, studies suggest the cylindrical axis (CA), defined as a line equidistant from contact points on the medial and lateral condylar surfaces from 10 o to 120 o flexion, more closely approximates the axis around which the tibia moves in space.Questions/purposes We examined the TEA and CA angles relative to mechanical axes to determine whether one more consistently and closely approximates the surgical goal of orthogonality to the mechanical axis. Methods Three-dimensional (3-D) models were reconstructed from CT scans of five cadaver limbs. Three observers repeated three measurement sets to locate the TEA, CA, and femoral mechanical and tibial mechanical axes. Angles of the TEA and CA relative to the mechanical axes were calculated in two-dimensions (2-D) and as 3-D projections and compared for differences in magnitude and variance. Results Angles between CA and the mechanical axes were closer to 90°than the TEA in 2-D (92°versus 94°for the femur, 93°versus 94°for the tibia) and 3-D (88°versus 87°for the femur, 88°versus 86°for the tibia). Variance of the TEA was higher than the CA in 2-D. Conclusions The CA forms angles more orthogonal to the mechanical axes of the thigh and leg than the TEA. Clinical Relevance Although we found a consistently greater deviation of the TEA from the mechanical axis than the CA with small differences, future studies will need to determine whether these differences are biomechanically or clinically important.

show abstract

Section: Discussioncontrasting

confidence: 80%

Section: Introductionmentioning

confidence: 99%

Cylindrical Axis, Not Epicondyles, Approximates Perpendicular to Knee Axes

Hancock

Winston

Bach

et al. 2013

Clinical Orthopaedics &Amp; Related Research

Self Cite

View full text Add to dashboard Cite

show abstract

“…Recent studies have suggested that the natural alignment of the knee in relation to the mechanical axis can be extremely variable [2][3][4]. Therefore, functional improvements in total knee replacement might focus on restoring the natural kinematics of the joint rather than aligning to a standardised mechanical axis.…”

mentioning

confidence: 99%

Initial experience with custom-fit total knee replacement: intra-operative events and long-leg coronal alignment

Spencer

Mont

McGrath

et al. 2008

International Orthopaedics (SICOT)

126

117

View full text Add to dashboard Cite

New technology using magnetic resonance imaging (MRI) allows the surgeon to place total knee replacement components into each patient's pre-arthritic natural alignment. This study evaluated the initial intraoperative experience using this technique. Twenty-one patients had a sagittal MRI of their arthritic knee to determine component placement for a total knee replacement. Cutting guides were machined to control all intraoperative cuts. Intra-operative events were recorded and these knees were compared to a matching cohort of the senior surgeon's previous 30 conventional total knee replacements. Post-operative scanograms were obtained from each patient and coronal alignment was compared to previous studies using conventional and computer-assisted techniques. There were no intra-operative or acute postoperative complications. There were no differences in blood loss and there was a mean decrease in operative time of 14% compared to a cohort of patients with conventional knee replacements. The average deviation from the mechanical axis was 1.2°of varus, which was comparable to previously reported conventional and computer-assisted techniques. Custom-fit total knee replacement appeared to be a safe procedure for uncomplicated cases of osteoarthritis.

show abstract

“…The reason is likely that the studies by Schulthies et al [22] and Kan et al [13] did not use a full-muscle model. Eckhoff et al [5,6] showed the angle between the sulcus axis calculated at the depth of the trochlear groove and the AA was 1.7°± 0.9°and the angle between the sulcus axis and the MA was 3.6°± 0.5°. This placed the axis of the sulcus Values are expressed as mean ± SD, with range in parentheses; 3D = three-dimensional; GCA = geometric center axis; TEA = transepicondylar axis.…”

Section: Discussionmentioning

confidence: 99%

“…The QV and its relationship to the femur is a measurement and may be an appropriate guide for rehabilitation and alignment of TKA components. Kan et al [13] Eckhoff et al [5,6] QV …”

Section: Discussionmentioning

confidence: 99%

The Vector of Quadriceps Pull is Directed From the Patella to the Femoral Neck

Tanifuji

Blaha

Kai

2013

Clinical Orthopaedics &Amp; Related Research

View full text Add to dashboard Cite

Background The quadriceps is the primary extensor of the knee. Its vector, which is perpendicular to the flexion axis of the knee, is important in understanding knee function and properly aligning total knee components. Three-dimensional (3-D) imaging enables evaluation using a 3-D model of each quadriceps component. Questions/purposes We calculated the direction and magnitude of the quadriceps vector (QV) and the precision of the measurement, and asked whether the QV bears a constant relationship to the femur and is aligned with an anatomically based axis on the femur. Methods Using CT data of 14 subjects, we created a 3-D solid model of each quadriceps muscle component. Vectors (3-D direction and length) for each quadriceps component were determined using principal component analysis for muscle direction and volume for magnitude; vector addition established the directional vector of the combined muscle. The combined vector originating in the center of the patella was compared with the shaft, mechanical, and spherical (center femoral head to center medial side of the knee) axes. Results The QV passed from the patella center proximally crossing the femoral neck between the femoral head and greater trochanter and was most closely aligned with the spherical axis. Conclusions The QV axis may be an important reference for alignment of total knee components. Clinical Relevance The spherical axis can be used in aligning total knee components to the flexion axis of the knee.

show abstract

Three-Dimensional Morphology of the Distal Part of the Femur Viewed in Virtual Reality

Cited by 80 publications

References 9 publications

Cylindrical Axis, Not Epicondyles, Approximates Perpendicular to Knee Axes

Cylindrical Axis, Not Epicondyles, Approximates Perpendicular to Knee Axes

Initial experience with custom-fit total knee replacement: intra-operative events and long-leg coronal alignment

The Vector of Quadriceps Pull is Directed From the Patella to the Femoral Neck

Contact Info

Product

Resources

About