Medial Proximal Femoral Angle better than Neck-Shaft Angle? Influence of Rotation on the Anteroposterior Radiograph

AbstractNeck-shaft angle (NSA) and medial proximal femoral angle (MPFA) describe the geometry of the proximal femur, but they are influenced by rotation. The MPFA is closer to the right angle and therefore assumed to be less influenced. This hypothesis was tested with a mathematical approach to compare the effects of rotation and their clinical relevance on both angles. We developed a three-dimensional (3D) geometrical model representing projectional radiography of the femoral axes under rotation and derived a mathematical equation. For validation purposes, we experimentally simulated projectional radiography and compared the results to those of the equation (five different inclinations of the femoral neck (IFN) each in 13 different rotations). The validated equation was used to determine the influence of rotation (–60° to +60°) on normal valued NSA and MPFA. The mean absolute difference between calculated and experimentally measured values was 0.6° (standard deviation [SD] 0.5; 0.0–2.2). The mean calculated difference between true and projected NSA was 7.1° (SD 7.1; 0.0–22.0), and for the MPFA, it was –1.9° (SD 2.2; –7.4 to 0.0). Clinically relevant deviations (≥5°) occurred at ≥30° external or ≥ 40° internal rotation for the NSA, for the MPFA at 60° external rotation. Mathematical modeling of radiographic projection of the IFN is possible to a high level of accuracy. Our results indicate that the NSA is significantly more susceptible to deviations caused by rotation than the MPFA. Clinicians must be aware of rotational influences in radiographic projection and possibly should use the MPFA instead of the NSA. The rotational influence during X-ray imaging must be controlled accurately, and femoral torsion should be quantified in computed tomography/magnetic resonance imaging (CT/MRI) scans if possible. 3-D bone models reconstructed from digital image data can be a future option for measuring true angles. Level of evidence was basic research.

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Internal Fixation with a Locking T-Plate for Proximal Humeral Fractures in Patients Aged 65 Years and Older

Clinics in Shoulder and Elbow ◽

10.5397/cise.2017.20.4.217 ◽

2017 ◽

Vol 20 (4) ◽

pp. 217-221 ◽

Cited By ~ 1

Author(s):

Jae Kwang Yum ◽

Min Kyu Seong ◽

Chi Woon Hong

Keyword(s):

Postoperative Complications ◽

Internal Fixation ◽

Internal Rotation ◽

Proximal Humerus ◽

External Rotation ◽

Osteoporotic Fractures ◽

Neck Shaft Angle ◽

Shaft Angle ◽

The Mean

BACKGROUND: The purpose of this study was to evaluate the clinical and radiographic outcomes of internal fixation with locking T-plates for osteoporotic fractures of the proximal humerus in patients aged 65 years and older.METHODS: From January 2007 through to December 2015, we recruited 47 patients aged 65 years and older with osteoporotic fractures of the proximal humerus. All fractures had been treated using open reduction and internal fixation with a locking T-plate. We classified the fractures in accordance to the Neer classification system; At the final follow-up, the indicators of clinical outcome-the range of motion of the shoulder (flexion, internal rotation, and external rotation) and the presence of postoperative complications-and the indicators of radiographic outcome-the time-to-union and the neck-shaft angle of the proximal humerus-were evaluated. The Paavolainen method was used to grade the level of radiological outcome in the patients.RESULTS: The mean flexion was 155.0° (range, 90°?180°), the mean internal rotation was T8 (range, T6?L2), and the mean external rotation was 66.8° (range, 30°?80°). Postoperative complications, such as plate impingement, screw loosening, and varus malunion were observed in five patient. We found that all patients achieved bone union, and the mean time-to-union was 13.5 weeks of the treatment. The mean neck-shaft angle was 131.4° at the 6-month follow-up. According to the Paavolainen method, “good” and “fair” radiographic results each accounted for 38 and 9 of the total patients, respectively.CONCLUSIONS: We concluded that locking T-plate fixation leads to satisfactory clinical and radiological outcomes in elderly patients with proximal humeral fractures by providing a larger surface area of contact with the fracture and a more rigid fixation.

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The Modified Femoral Neck-Shaft Angle: Age- and Sex-Dependent Reference Values and Reliability Analysis

BioMed Research International ◽

10.1155/2016/8645027 ◽

2016 ◽

Vol 2016 ◽

pp. 1-7 ◽

Cited By ~ 3

Author(s):

Christoph Kolja Boese ◽

Michael Frink ◽

Janine Jostmeier ◽

Stefan Haneder ◽

Jens Dargel ◽

...

Keyword(s):

Femoral Neck ◽

Reference Values ◽

Interrater Reliability ◽

High Reliability ◽

Age Groups ◽

Absolute Difference ◽

Neck Shaft Angle ◽

Shaft Angle ◽

The Mean ◽

Novel Concept

Background. The femoral neck-shaft angle (NSA) is of high importance for the diagnostics and treatment of various conditions of the hip. However, rotational effects limit its precision and applicability using plain radiographs. This study introduces a novel method to measure the femoral NSA: the modified NSA (mNSA), possibly being less susceptible against rotational effects compared to the conventional NSA.Patients and Methods. The method of measurement is described and its applicability was tested in 400 pelvis computed tomography scans (800 hips). Age- and gender-dependent reference values are given and intra- and interrater reliability are analyzed.Results. The mean age of all 400 patients (800 hips) was 54.32 years (18–100, SD 22.05 years). The mean mNSA was 147.0° and the 95% confidence interval was 146.7°–147.4°. Differences of the mNSA between sexes, age groups, and sides were nonsignificant. The absolute difference between NSA and mNSA was 16.3° (range 3–31°; SD 4.4°); the correlation was high (0.738;p<0.001). Overall, the intra- and interrater reliability were excellent for the mNSA.Interpretation. We introduced a novel concept for the analysis of the neck-shaft angle. The high reliability of the measurement has been proven and its robustness to hip rotation was demonstrated.

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Analysis of Proximal Femoral Parameters in Adolescent Idiopathic Scoliosis

Advances in Orthopedics ◽

10.1155/2019/3948595 ◽

2019 ◽

Vol 2019 ◽

pp. 1-7 ◽

Cited By ~ 1

Author(s):

Máté Burkus ◽

Ádám T. Schlégl ◽

Kristóf József ◽

Ian O’Sullivan ◽

István Márkus ◽

...

Keyword(s):

Adolescent Idiopathic Scoliosis ◽

Idiopathic Scoliosis ◽

Mechanical Axis ◽

Three Dimensional ◽

Femoral Shaft ◽

Neck Shaft Angle ◽

Shaft Angle ◽

Spinal Abnormality ◽

Lower Neck ◽

Femoral Mechanical Axis

Background. Assessment of the proximal femoral parameters in adolescent idiopathic scoliosis using three-dimensional radiological image reconstructions may allow better characterization than conventional techniques. Methods. EOS 3D reconstructions of spines and femurs of 320 scoliotic patients (10-18 years old) and 350 control children lacking spinal abnormality were performed and 6 proximal femoral parameters measured. Results. Individuals with adolescent idiopathic scoliosis showed a small but statistically significant decrease in neck shaft angle (average difference=2.58°) and a higher (0.22°) femoral mechanical axis–femoral shaft angle. When the two sides were compared based on curve direction, greater changes in the neck shaft angle and femoral mechanical axis–femoral shaft angle were found on the side of the convexity. Conclusions. Patients with adolescent idiopathic scoliosis were found to have a small but significantly lower neck shaft angle and higher femoral mechanical axis–femoral shaft angle, which related to the curve direction. This is postulated to be due to mechanical compensation for altered balance and centre of gravity associated with a scoliosis deformity, although the observed difference likely has negligible clinical effect.

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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]

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Fibular strut allograft influences reduction and outcomes after locking plate fixation of comminuted proximal humeral fractures in elderly patients: a retrospective study

BMC Musculoskeletal Disorders ◽

10.1186/s12891-019-2907-3 ◽

2019 ◽

Vol 20 (1) ◽

Cited By ~ 1

Author(s):

Xueliang Cui ◽

Hui Chen ◽

Binbin Ma ◽

Wenbin Fan ◽

He Li

Keyword(s):

Elderly Patients ◽

Clinical Outcomes ◽

Locking Plate ◽

External Rotation ◽

Plate Fixation ◽

Proximal Humeral Fractures ◽

Humeral Fractures ◽

Neck Shaft Angle ◽

Shaft Angle ◽

Head Height

Abstract Background Proximal humeral fractures (PHFs) are the third most commonly occurring fractures in elderly patients. Most of these fractures can be treated with conservative methods, but the optimal surgical treatment strategy for unstable fractures in elderly patients remains controversial. This study aimed to compare the radiological and clinical outcomes between locking compression plate (LCP) fixation and LCP fixation with fibular allograft implantation for the treatment of comminuted PHFs. Methods We retrospectively reviewed 60 patients (mean age, 72.75 years) with closed 3- or 4-part fractures, and a minimum of 2 years of follow-up. Fracture reduction was quantitatively determined by humeral head height (HHH) and neck-shaft angle (NSA). The clinical outcome was evaluated by Constant-Murley score (CMS) and American Shoulder and Elbow Surgeons (ASES) score. Result The average radiological changes were higher in the LCP group than in the locking plate with fibular allograft group (HHH of 4.16 mm vs 1.18 mm [p < 0.001] and NSA of 9.94° versus 3.12° [p < 0.001]) . The final average outcome scores were lower in the LCP group than in the FA group (CMS of 73.00 vs 78.96 [p = 0.024] and ASES score of 72.80 vs 78.64 [p = 0.022]). The FA group showed better forward elevation (p = 0.010) and abduction (p = 0.002); however, no significant differences were observed for shoulder external rotation or internal rotation. The number of complications was higher in the LCP group (28.57%) than in the FA group (1.2%) (p < 0.001). Conclusion For comminuted PHFs in elderly patients, LCP fixation combined with a fibular allograft is reasonable option to ensure satisfactory radiological and clinical outcomes. Trial registration ZDYJLY(2018)New-9. Name of registry: IEC for clinical Research of Zhongda Hospital, Affiliated to Southeast University. Date of registration: 2018-05-17.

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Functional and Radiological Outcome of Unstable Intertrochanteric Fracture in Old Age Treated with Proximal Femoral Nail Antirotation-2

JOURNAL FOR CLINICAL AND DIAGNOSTIC RESEARCH ◽

10.7860/jcdr/2021/47653.14751 ◽

2021 ◽

Author(s):

OP Jamshad ◽

Jacob Mathew ◽

Raju Karuppal

Keyword(s):

Proximal Femoral Nail ◽

Harris Hip Score ◽

Intertrochanteric Fractures ◽

Biological Reduction ◽

Neck Shaft Angle ◽

Femoral Nail ◽

Unstable Intertrochanteric Fracture ◽

Shaft Angle ◽

The Mean ◽

Proximal Femoral Nail Antirotation

Introduction: Intertrochanteric fractures are prevalent in the elderly, which leave patients with functional restrictions. Proximal Femoral Nail Antirotation-2 (PFNA) was developed to achieve better fixation strength, particularly in the presence of osteoporotic unstable intertrochanteric fractures. Aim: To evaluate the role and result of PFNA-2 in the treatment of unstable intertrochanteric fractures in geriatric patients. Materials and Methods: A prospective analytical study was conducted in 35 patients with unstable intertrochanteric fractures. They were followed-up clinically and radiologically for one year. The quality of fixation was assessed, by neck-shaft angle and Tip Apex Distance (TAD). A functional assessment was done with the Harris Hip Score (HHS). Results: The mean follow-up period was 13 months (range, 12-14). The mean age of patients was 65.6 years and the majority were female patients (62.85%). Functional results according to modified HHS were found to be excellent in 6 (17.1%) patients, good in 14 (40%) patients, fair in 12 (34.3%) patients and poor in 3 (8.6%) patients. The average HHS in this study was 81.6. Statistical analysis was performed using Statistical Package for Social Sciences (SPSS) version 16.0. Conclusion: PFNA-2 helps in achieving biological reduction and good stability which enables early mobilisation and prevention of excessive collapse. A good functional outcome could be achieved when the radiological parameters are restored, i.e., TAD <25 mm and neck-shaft angle difference <5° (compared to the opposite side).

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Trans-lateral Decubitus Radiograph of the Hip: A New View to Measure the Version of the Femoral Stem

10.21203/rs.2.16597/v1 ◽

2019 ◽

Author(s):

Yong-Chan Ha ◽

Jun-Il Yoo ◽

Joong-Mo Ahn ◽

Young-Kyun Lee ◽

Yusuhn Kang ◽

...

Keyword(s):

Ct Scan ◽

Femoral Stem ◽

Neck Shaft Angle ◽

Radiological Measurement ◽

Ct Measurements ◽

Radiological Measurements ◽

Shaft Angle ◽

Lateral Decubitus ◽

The Mean ◽

Stem Version

Abstract Background We developed a radiological method, trans-lateral decubitus view, to measure stem version and assessed its reliability as well as the validity.Methods Trans-lateral decubitus view of the hip was a lateral radiograph, which was taken with the patient in lateral decubitus position, hip extension, 90° knee flexion and patella facing forward. In 40 patients, who underwent total hip replacement (THR), a trans-lateral decubitus view and CT scan of the hip were taken. Three observers measured stem neck-shaft angle (α) on hip AP view, and the stem anteversion (β), which was the angle between the axis of stem neck and axis of the femur, on the trans-lateral decubitus view. The stem version (θ) was calculated using the formula; θ = arc ((tan (180°-β) /tan (180°-α)). The intra and inter-observer reliabilities of each measurement were examined. The radiological measurements were compared with those on the CT scan to evaluate their validity.Results The mean stem anteversion on radiological measurement was 23.72° (SD 8.17) and the mean CT measurement was 23.91° (SD 10.25) (p = 0.929). The intra- and interobserver reliabilities of the radiological measurements were 0.934 and 0.931, respectively. Those of CT measurements were 0.941 and 0.942, respectively. When the radiological anteversion was between -30° and 30°, the correlation coefficient between radiological measurements and CT measurements was 0.729 (p = 0.001).Conclusion The trans-lateral decubitus method appears reliable and valid for the measurement of femoral stem version. Trial Registration: NCT02554149 (29 March 2016).

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Three-dimensional morphological study of the proximal femur in Crowe type IV developmental dysplasia of the hip

Journal of Orthopaedic Surgery and Research ◽

10.1186/s13018-021-02789-5 ◽

2021 ◽

Vol 16 (1) ◽

Author(s):

Yuhui Yang ◽

Weihong Liao ◽

Weiqun Yi ◽

Hai Jiang ◽

Guangtao Fu ◽

...

Keyword(s):

Femoral Neck ◽

Proximal Femur ◽

Three Dimensional ◽

Developmental Dysplasia ◽

Medullary Canal ◽

Femoral Offset ◽

Neck Shaft Angle ◽

Type Iv ◽

Shaft Angle ◽

Dysplasia Of The Hip

Abstract Background When performing femoral reconstruction in patients with Crowe type IV developmental dysplasia of the hip (DDH), anatomical deformity presents many technical challenges to orthopedic surgeons. The false acetabulum is suggested to influence load transmission and femoral development. The aim of this study was to describe the morphological features of dysplastic femurs in Crowe type IV DDH and further evaluate the potential effect of the false acetabulum on morphological features and medullary canal of Crowe type IV femurs. Methods We analyzed preoperative computed tomography scans from 45 patients with 51 hips (25 hips without false acetabulum in the IVa group and 26 hips with false acetabulum in the IVb group) who were diagnosed with Crowe type IV DDH and 30 normal hips in our hospital between January 2009 and January 2019. Three-dimensional reconstruction was performed using Mimics software, and the coronal femoral plane was determined to evaluate the following parameters: dislocation height, dislocation ratio, height of the femoral head (FH), height of the greater trochanter (GT), GT–FH height discrepancy, height of the isthmus, neck-shaft angle, femoral offset and anteversion of the femoral neck. The mediolateral (ML) width, anterolateral (AP) width and diameter of medullary canal of the proximal femur were measured on the axial sections. Further, canal flare index (CFI), metaphyseal-CFI and diaphyseal-CFI were also calculated. Results Compared with the normal femurs, the Crowe type IV DDH femurs had a higher femoral head, larger GT–FH height discrepancy, larger femoral neck anteversion, higher isthmus position and smaller femoral offset. Dislocation height and dislocation rate were significantly larger in the IVa DDH group (65.34 ± 9.83 mm vs. 52.24 ± 11.42 mm). Further, the IVb femurs had a significantly lower isthmus position, larger neck-shaft angle and smaller femoral neck anteversion than IVa femurs. The ML, AP canal widths and the diameter of medullary canal in both DDH groups were significantly smaller than the normal group. Dimensional parameters of IVa femurs were also narrower than IVb femurs in most sections, but with no difference at the level of isthmus. According to the CFIs, the variation of proximal medullary canal in IVb femurs was mainly located in the diaphyseal region, while that in IVa femurs was located in the whole proximal femur. Conclusions High dislocated femurs are associated with more anteverted femoral neck, smaller femoral offset and narrower medullary canal. Without stimulation of the false acetabulum, IVa DDH femurs were associated with higher dislocation and notably narrower medullary canal, whose variation of medullary canal was located in the whole proximal femur.

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Valgus Osteotomy Outcome for Treating Femoral Neck Nonunion in Young and Active Patients

Journal of Research in Orthopedic Science ◽

10.32598/jrosj.8.2.400.1 ◽

2021 ◽

Vol 8 (2) ◽

pp. 65-70

Author(s):

Kaveh Gharanizadeh ◽

◽

Hamed Tayyebi ◽

Abbas Esmaeli ◽

Maziar Rajei ◽

...

Keyword(s):

Total Hip Arthroplasty ◽

Femoral Neck ◽

Hip Arthroplasty ◽

Limb Length Discrepancy ◽

Osteotomy Site ◽

Valgus Osteotomy ◽

Neck Shaft Angle ◽

Shaft Angle ◽

The Mean

Background: Femoral neck fracture nonunion is a frequent and challenging complication, with several surgical options. Objectives: The present study reported the outcome of valgus osteotomy for treating femoral neck nonunion in patients aged <65 years. Methods: This case series research included young patients who underwent valgus osteotomy for treating femoral neck nonunion or device failure of the index surgery. The fixation of the osteotomy site was performed using either a dynamic hip screw or a fixed angle blade. The union of the neck and osteotomy site (subtrochanteric region) was evaluated by monitoring callus formation in the postoperative radiographs. Limb length discrepancy, Pauwels’ angle, and the neck-shaft angle were evaluated before the surgery and at the last follow-up. Postoperative complications were extracted from the explored patients’ profiles. Results: Twenty patients with a Mean±SD age of 27.2±10.8 years were examined in this study‎. The Mean±SD follow-up time of the patients was 6.1±3.9 years. The femoral neck was united in 18 patients in a Mean±SD period of 5.1±2.3 months. The Mean±SD limb length discrepancy was measured as 1.3±0.8 cm before and 0.5±0.7 cm after the ‏osteotomy. The Mean±SD Pauwels’ angle was calculated as 65.5±16.9º before and 32.4±16.2º after the osteotomy. The Mean±SD neck-shaft angle was computed to be 121.9±22.8º before and 144.5±17.7º after the osteotomy. Revision surgery was performed for 6 (30%) patients. This measure included device removal in 4 and total hip arthroplasty in 2 patient. Conclusion: Valgus osteotomy is a safe and efficient technique for managing femoral neck nonunion. Therefore‎, this approach is suggested as a good alternative for total hip arthroplasty, particularly in young and active patients‎.

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