Femoral Neck Version Affects Medial Femorotibial Loading

The aim of this study was to provide a preliminary evaluation of the possible effect that femoral version may have on the bearing equilibrium conditions developed on the medial tibiofemoral compartment. A digital 3D solid model of the left physiological adult femur was used to create morphological variations of different neck-shaft angles (varus 115, normal 125, and valgus 135 degrees) and version angles (−10, 0, and +10 degrees). By means of finite element modeling and analysis techniques (FEM-FEA), a virtual experiment was executed with the femoral models aligned in a neutral upright position, distally supported on a fully congruent tibial tray and proximally loaded with a vertical only hip joint load of 2800 N. Equivalent stresses and their distribution on the medial compartment were computed and comparatively evaluated. Within our context, the neck-shaft angle proved to be of rather indifferent influence. Reduction of femoral version, however, appeared as the most influencing parameter regarding the tendency of the medial compartment to establish its bearing equilibrium towards posteromedial directions, as a consequence of the corresponding anteroposterior changes of the hip centre over the horizontal tibiofemoral plane. We found a correlation between femoral anteversion and medial tibiofemoral compartment contact pressure. Our findings will be further elucidated by more sophisticated FEM-FEA and by clinical studies that are currently planned.

Download Full-text

The association between femoral neck shaft angle and degenerative disease of the hip in a cadaveric model

Hip International ◽

10.1177/11207000211013029 ◽

2021 ◽

pp. 112070002110130

Author(s):

Leigh-Anne Tu ◽

Douglas S Weinberg ◽

Raymond W Liu

Keyword(s):

Femoral Head ◽

Femoral Neck ◽

Hip Osteoarthritis ◽

Volume Ratio ◽

Femoral Head Coverage ◽

Neck Shaft Angle ◽

Hip Arthritis ◽

Femoral Version ◽

Shaft Angle ◽

The Impact

Background: While the influences of acetabular dysplasia and overcoverage on hip arthritis have been studied, the impact of femoral neck-shaft angle on hip arthritis is much more poorly understood. The purpose of this study is to determine if a relationship exists between neck shaft angle and the development of osteoarthritis, a better understanding of which would be useful to surgeons planning osteotomies about the hip. Methods: 533 cadaveric femora and acetabulae (1066 total) from the Hamann-Todd Osteological Collection (Cleveland, OH) were acquired. We measured true neck shaft angle using an AP photograph with the femoral neck parallel to the table. Femoral head volume to acetabular volume ratio, representing femoral head coverage, as well as femoral version were utilised. Correlation between neck shaft angle, femoral version, femoral head coverage and osteoarthritis were evaluated with multiple regression analysis. Results: The mean age and standard deviation was 56 ± 10 years. There were 64 females (12%) and 469 males. There were 380 Caucasians (71%) and 153 African-Americans. Mean femoral version was 11° ± 12° and mean true neck shaft angle was 127.7° ± 5.9° There was a strong correlation between age and arthritis (standardised beta 0.488, p < 0.001). There was a significant correlation between increasing true neck shaft angle and decreasing hip arthritis (standardised beta -0.024, p = 0.038). In the femoral head overcoverage subset, increasing true neck shaft angle was still significantly associated with decreasing hip arthritis (standardised beta −0.088, p = 0.018), although this relationship was not significant with femoral head undercoverage subset. Conclusions: With sufficient acetabular coverage, a relative increase in femoral neck shaft angle within the physiologic range is associated with decreased hip osteoarthritis. Clinical relevance: An understanding of the relationship between femoral neck shaft angle and hip osteoarthritis could be useful for surgeons planning pelvic or proximal femur osteotomies in children.

Download Full-text

Femoral Version, Neck-Shaft Angle, and Acetabular Anteversion in Chinese Han Population

Medicine ◽

10.1097/md.0000000000000891 ◽

2015 ◽

Vol 94 (21) ◽

pp. e891 ◽

Cited By ~ 12

Author(s):

Nan Jiang ◽

Lin Peng ◽

Mohammed Al-Qwbani ◽

Guo-Ping Xie ◽

Qin-Meng Yang ◽

...

Keyword(s):

Chinese Han Population ◽

Acetabular Anteversion ◽

Chinese Han ◽

Han Population ◽

Neck Shaft Angle ◽

Femoral Version ◽

Shaft Angle

Download Full-text

Standard Radiographic Assessment of Femoral Cam Morphology is Influenced by Neck-Shaft Angle and Femoral Version

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967120s00392 ◽

2020 ◽

Vol 8 (7_suppl6) ◽

pp. 2325967120S0039

Author(s):

Layla Haidar ◽

Ryan Warth ◽

Erinn Pemberton Annie Waite ◽

Alfred Mansour

Keyword(s):

Femoral Head ◽

Alpha Angle ◽

Three Dimensional ◽

Neck Shaft Angle ◽

Incremental Change ◽

Observer Reliability ◽

Angle Measurements ◽

Femoral Version ◽

Shaft Angle ◽

Head Neck

Objectives: Cam-type femoroacetabular impingement (FAI) is a three-dimensional (3D) deformity that is still difficult to assess using traditional two-dimensional (2D) radiographic views. While measurements of alpha angle and head-neck offset are used to estimate the likelihood of actual impingement, these 2D measurements do not account for z-axis variations in femoral version (FV) and neck-shaft angle (NSA). The purpose of this qualitative proof-of-concept study was to evaluate the potential variation in alpha angle and neck-shaft offset measurements with incremental changes in NSA and FV by simulating traditional radiographic views with software-generated Digitally-Reconstructed Radiographs (DRRs). We hypothesize that incremental changes in hip morphology will produce qualitative changes in alpha angle and neck-shaft offset. Methods: 3D-CT reconstruction images were obtained from one subject with symptomatic cam-type FAI. The 3D reconstruction was cleaned to include only the femoral head, neck and subtrochanteric region along with the ipsilateral hemipelvis. Using 3D medical image processing software (Mimics; Materialise, Inc.; Belgium), the pre-processed 3D model was manipulated in a standardized manner to simulate 5-degree incremental variations in FV and NSA (-15 degrees to +15 degrees for FV; -15 degrees to +10 degrees for NSA). Negative FV reflected external rotation of the femoral head-neck unit, whereas negative NSA reflected abduction of the femoral head-neck unit. Each modified 3D model was then used to generate DRRs corresponding to traditional 2D radiographic views used for assessment of cam-FAI (Anteroposterior [AP], False Profile [FP]), Cross Table Lateral [CTL], Frog Leg Lateral [FLL], 45- and 90-degree Dunn [45D and 90D, respectively]. Alpha angle and head-neck offset were measured on each radiographic view corresponding to each incremental change in FV and NSA. All measurements utilized the perfect circle technique and were made by two independent observers for assessment of inter-observer reliability. Two-way random effects ANOVA was used for statistical assessment of inter-observer reliability and reported as intra-class correlation coefficients (κ). Comparisons between groups were performed using two-tailed paired t-tests assuming unequal variance. P-values less than 0.05 were considered statistically significant. Results: Inter-observer reliability (κ) for head-neck offset and alpha angles were 0.46 (fair) and 0.88 (excellent), respectively. Variations in head-neck offset and alpha angle with incremental variations in FV and NSA are summarized in Figure 1. There were statistically significant changes in mean alpha angles when the NSA was adjusted from Neutral to -5 degrees (p=0.01) and from -5 degrees to -10 degrees (p<0.001). There were no statistically significant differences in alpha angles or head-neck offsets between each incremental change in FV (p<0.05). Alpha angle measurements were significantly more variable than head-neck offset measurements for all variations in FV (p<0.001) and NSA (p=0.02) (Figure 2). Conclusion: Two-dimensional evaluation of three-dimensional Cam morphology (alpha angle and head-neck offset) was found to be significantly affected by alterations in femoral version and head-neck offset. Head-neck offset measurements were significantly less variable than alpha angle measurements across all FVs and NSAs within each radiographic view. Future work should be done to develop standardized procedures for routine 3D radiographic assessment of cam-type FAI. [Figure: see text][Figure: see text]

Download Full-text

Femoral Neck-shaft Angle Differs but Femoral Anteversion is Constant in Osteological Specimens with and without a Cam Deformity of the Proximal Femur

Arthroscopy The Journal of Arthroscopic and Related Surgery ◽

10.1016/j.arthro.2013.09.051 ◽

2013 ◽

Vol 29 (12) ◽

pp. e207 ◽

Cited By ~ 1

Author(s):

Jonathan Streit ◽

Jeremy Gebhart ◽

Asheesh Bedi ◽

Charles Bush-Joseph ◽

Shane Nho ◽

...

Keyword(s):

Femoral Neck ◽

Proximal Femur ◽

Femoral Anteversion ◽

Neck Shaft Angle ◽

Cam Deformity ◽

Shaft Angle

Download Full-text

Femoral Neck Shaft Angle is Not Correlated with Femoral Version: A Retrospective Study of Computed Tomography Scans

Injury ◽

10.1016/j.injury.2021.12.026 ◽

2021 ◽

Author(s):

Patrick J. Kellam ◽

Miranda J. Rogers ◽

Luke Myhre ◽

Graham J. Dekeyser ◽

Travis G. Maak ◽

...

Keyword(s):

Computed Tomography ◽

Retrospective Study ◽

Femoral Neck ◽

Neck Shaft Angle ◽

Femoral Version ◽

Computed Tomography Scans ◽

Shaft Angle

Download Full-text

Femoral Version and Neck Shaft Angle

Journal of Pediatric Orthopaedics ◽

10.1097/01241398-199305000-00021 ◽

1993 ◽

Vol 13 (3) ◽

pp. 382-388 ◽

Cited By ~ 42

Author(s):

Freeman Miller ◽

Marco Merlo ◽

Youhui Liang ◽

Paul Kupcha ◽

Janine Jamison ◽

...

Keyword(s):

Neck Shaft Angle ◽

Femoral Version ◽

Shaft Angle

Download Full-text

The effect of valgus and varus femoral osteotomies on measures of anteversion in the dog

Veterinary and Comparative Orthopaedics and Traumatology ◽

10.3415/vcot-16-09-0138 ◽

2017 ◽

Vol 30 (03) ◽

pp. 184-190 ◽

Cited By ~ 3

Author(s):

Rachel Adams ◽

Brad Gilleland ◽

Farrah Monibi ◽

Samuel Franklin

Keyword(s):

Repeated Measures ◽

Three Dimensional ◽

Frontal Plane ◽

Femoral Anteversion ◽

Coxa Vara ◽

Neck Shaft Angle ◽

Repeated Measures Analysis ◽

Shaft Angle ◽

Coxa Valga ◽

Head Neck

Summary Objective: To determine whether femoral osteotomies that change frontal plane alignment without affecting torsion influence anteversion and inclination. Methods: Femurs without deformity were scanned to create three-dimensional reconstructions. The femoral head-neck axis was identified by placement of a virtual intra-medullary pin. A proximal osteotomy was simulated to create three conditions while keeping torsion constant: Normal, Coxa Valga (neck-shaft angle increased by 12°), and Coxa Vara (neck-shaft angle decreased by 12°). Femoral anteversion was measured from an axial image in all three conditions. Femoral inclination was calculated for all conditions using the neck-shaft and anteversion angles. Changes in anteversion and inclination were calculated and compared using a one-way repeated measures analysis of variance. Distal femoral osteotomies were then simulated with the native femurs, inducing 18° of distal varus with no change to torsion. Changes in anteversion and inclination for the Normal and Distal Varus conditions were calculated and compared by a paired t-test. Results: Version changed by a mean of 13.9° (± 1.5; p <0.0001) from the Coxa Valga to Coxa Vara conditions while inclination changed by a mean of 1.3° (± 0.39; p <0.01). Version changed by a mean of 6.6° (± 0.7; p <0.0001) between the Distal Varus and Normal conditions while inclination changed by a mean of –3.8° (± 0.75; p <0.001). Clinical significance: Femoral version changes with changing frontal plane alignment even when torsion is constant. This should be considered when correcting femoral deformities.

Download Full-text