Medial Proximal Femoral Angle Research Articles

Observational study of radiographic analysis of axial alignments of the lower extremity in northwest Indian adult population

Background: The current study is conducted to find the radiographic axial alignments of the lower extremity in north-west Indian adult population.Methods: A observational study was conducted from May 2018 to May 2020. A total of 137 patients aged between 18-30years coming to hand clinic were randomly selected and full-length weight bearing anterior posterior and lateral view x-rays of left leg was performed and angles were measured using bone ninja application for following axial angles. Femoral neck shaft angle (frontal/sagittal plane), medial proximal femoral angle, anatomical/mechanical lateral distal femoral angle, medial proximal tibial angle, lateral distal tibial angle, posterior proximal/distal femoral angle, anterior distal femoral angle, joint line congruence angle (knee joint), mechanical/anatomical tibio femoral angle.Results: In our study medial inclination of the tibial plateau in Indian adult population is 5.4+/- 2.4 degree was greater than the commonly reported 3 degree. The tibio femoral valgus angle was 5.4degree with a range of 4-8 degree.Conclusion: Adult Indian population have more varus alignment of knee and significant higher medial inclination of tibial plateau than the counterpart western population. A 5 degree of external rotation of femoral component instead of commonly used 3degree is necessary while performing total knee arthroplasty in Indian population.

Postoperative Immobilization After Hip Reconstruction in Cerebral Palsy: No Difference Between Hip Spica and Abduction Pillow

PurposeThis study aims to compare radiographic outcomes and complication rates of immobilization with an abduction pillow to spica casting for postoperative care after a hip reconstruction with varus derotational proximal femur osteotomy (VDRO) with or without pelvic osteotomy for children with cerebral palsy (CP).Methods233 children (1–18 years old) diagnosed with CP that underwent VDRO with or without pelvic osteotomy were identified, of which 188 patients were immobilized with a spica cast and 45 were immobilized with an abduction pillow, based on surgeon preference. 123 (65%) in the Spica group and 21 (47%) in the pillow group had pelvic osteotomies. Demographic data and complication rates were collected. Radiographic parameters, including anatomic medial proximal femoral angle (aMPFA), acetabular index (AI) and migration percentage (MP), were measured for each patient at the completion of surgery, six weeks post-operatively, and one year post-operatively.ResultsThere was not a statistically significant difference in BMI (p = 0.285), gender distribution (p = 0.984), or median follow-up time (p = 0.314) between groups. Rates of complications were consistent among groups with no differences in instances of delayed unions (p = 0.10), subluxations (p = 0.55), infection (p = 0.71), or non-unions (p = 0.10). There was no statistically significant difference in number of patients with an ideal aMPFA, AI, or MP (p = 0.44, p = 0.19, p = 1.00) at one year post-operatively.ConclusionsImmobilization with an abduction pillow is a safe and effective alternative to hip spica casting following hip reconstruction.

Morfometrijski parametri proksimalnog okrajka butne kosti i njihov uticaj na zglob kuka

Introduction: The femur is a long bone (ossa longa) that forms the hip and knee joints, supporting the weight of almost the entire body. This study is based on analyzing certain angles on the proximal femur that represent anthropometrically and surgically significant parameters, with clinical significance in diseases such as metabolic and degenerative bone disorders, arthritis, various hip trauma and disease. Aim: Determining the significance of certain morphometric parameters of the proximal femur and exploration of their impact on the hip joint. Material and methods: This cross-sectional study encompasses measuring four parameters: shaft length, the collodiaphyseal angle (CDA), the medial proximal femoral angle (MPFA) and the lateral proximal femoral angle (LPFA), on adult femora belonging to the archive of the Institute of anatomy "Niko Miljanić" of the Univerisity of Belgrade, Faculty of Medicine. A digital goniometer precise to two decimal places was used for all measurements. Results: Forty-seven femora were examined, 25 of which were left and 22 right femora of unknown gender and age, since none of the examined parameters could be used in procuring such information. The average femoral shaft length was 39.9 ± 2.7 cm, the shortest 34.8 cm and the longest 45.7 cm. The Collodiaphyseal angle (CDA) was 127.64 ± 4.25° on average, with the minimum being 119.1° and the maximum 137.7°. Average LPFA was 87.21 ± 3.07°, the lowest 81.6 and the highest 93.0°. Finally, MPFA was 86.9 ± 3.73° on average, with the smallest being 78.7° and the largest 94.5°. The Medial proximal femoral angle of right femora was significantly lower than the MPFA of left femora (p = 0,016). Conclusion: Eleven samples had a CDA below normal (< 124°), with three being defined as coxa vara (CDA < 120°). One had a CDA above normal (> 135°), being defined as coxa valga. Outside of reference values, LPFA was determined on 11 samples, being below normal (<85°) in all of them, whilst MPFA had 13 with only one of them being below normal (< 80°).

Post-operative radiographic measures of pelvic limb alignment in dogs with medial patellar luxation after trochlear wedge recession versus trochlear block recession surgery.

Background and Aim:Anatomical and mechanical femoral angles are quite different among dog breeds. Most published data are about large dog breeds, however, medial luxation of patella is more common in small breeds. Measures of pelvic limb alignment are important for outcome of patellar luxation surgery. Therefore, the aim of the present study was to compare the values of anatomical and mechanical femoral and tibial angles in dogs before, immediately after, and 1 month after surgery for correction of medial patellar luxation (MPL).Materials and Methods:The study was conducted with 54 dogs (67 stifle joints) from four small breeds that underwent surgery by either trochlear block recession (36 stifle joints) or trochlear wedge recession (31 stifle joints) techniques.Results:In both trochleoplasty techniques, statistically significant differences in the values of the anatomical medial proximal femoral angle (aMPFA), anatomical lateral distal femoral angle (aLDFA), and femoral varus angle (in MPL Grade II) and of aMPFA and Q-angle (in MPL Grade III) were found out.Conclusion:After block recession surgery, more angles were positively influenced and this effect was more pronounced in patients with MPL Grade II.

3D-ANALYSIS OF LOWER LIMB ANATOMY: NORMAL VALUES FOR JOINT ANGLES AND ALIGNMENT

Aims and Objectives:The analysis of lower limb anatomy is mandatory in deformity surgery and total knee replacement. Standard values for joint angles and alignment are only available for 2D images using long standing and lateral radiographs. In contrast, 3D bone models realistically represent the anatomy and are independent of position and projection. Using a self-developed, standardised and validated protocol for 3D analysis of lower limb geometry, standard values for specific joint angles and axes can be obtained in a young cohort for the first time.Materials and Methods:After power and sample size analysis, 60 thin-slice CTs of the entire leg were analysed (30 patients, 13 f, 17 m; age = 33.8 [18-50 years]). After segmentation all 24 relevant bony landmarks were set using our standardised analysis method. Results of joint angles and mechanical axis deviation are calculated automatically. Mean values are stated with standard deviations to describe a possible reference range.Results:The mean neck-shaft angle (NSA) was 133±10° and the mean medial proximal femoral angle (MPFA) 85±9°. Around the knee joint, the mean mechanical lateral distal femoral angle (mLDFA) was 87±4° and the medial proximal tibial angle (MPTA) 88±5°. Medial and lateral slope averaged 12±7° and 9±8°. The deviation of the frontal mechanical leg axis from the knee joint center (MAD frontal) was 7±15mm and the mechanical femoro-tibial angle (HKA) 175±6°. Women showed a smaller mLDFA than men (86.4° vs. 87.8°, p<0.05) and a larger joint line convergence angle (JLCA 2.5° vs. 1.4°, p<0.01) representing a more valgiform anatomy.Conclusion:The standardised 3D analysis enabled reference ranges for the relevant joint angles and axes to be defined on the 3D bone model for the first time. The results redefine reference ranges for 3D measurements similar to existing 2D measurements on long standing radiographs. The systematic analysis of the complex 3D anatomy results in a multitude of new questions and possibilities in preoperative planning.

Preoperative planning of constitutional varus alignment in patients with varus knees and coronal femoral lateral bowing

Objective: To investigate the preoperative constitutional varus alignment (CA) inpatients withvarus osteoarthritic knees and coronal femoral lateral bowing (FLB) by comparing the femoral axis of the patients and volunteers' with straight femoral shaft (SFS) and healthy knees, which would be used to guide the selection of valgus correction angle(VCA) of distal femur in total knee anthroplasty (TKA). Methods: From January 2018 to December 2018, 45 nonconsecutive patients (90 knees) with varus osteoarthritic knees and obvious FLB (>5°) received primary TKA,and 50 limbs with healthy knees and SFS in 25 volunteers were studied at Xinqiao Hospital.The medial proximal femoral angle (MPFA) and anatomic lateral distal femoral angle (a-LDFA) were measured and compared between the two groups.The VCA formed by distal femoral mechanical axis (DMA) and distal femoral anatomic axis (DAA) in patients and the VCA based on neutral mechanical axis (NMA) in volunteers were also compared. The Pearson's correlation analysis was performed between the angle of bowing (α) and the VCA based on NMA in patients. The measurement data was compared with t test between the two groups. Results: The results showed that the MPFA and the a-LDFA were not significantly different between the volunteers with SFS and patients with FLB (MPFA:84.9°±3.7° vs 85.6°±1.8° and a-LDFA:81.7°±1.7° vs 81.2°±1.6°, t=1.26, 1.70, both P>0.05). The VCA based on NMA in volunteers with SFS was 5.5°±0.6°(4.5°-7.4°), the preoperative DAA-DMA angle was 5.3°±0.7°(4.3°-7.8°) in patients with FLB, there was no significant difference between the two groups (t=1.70, P=0.09). The angle of bowing (α) was 7.9°±2.9° (6°-16°), the VCA based on NMA was 8.4°±1.5°(5°-10°), there was a significantly positive correlation between VCA and α (R=0.607, P<0.01). Conclusion: There is no significantly proximal or distal femoral deformity in patients with varus osteoarthritic knee and FLB (>5°), the degree of the DMA-DAAangle based on the DMA doesn't change with the increasing angular deformity of the bowing, then the bowing would be reserved if the distal femur is cut based on DMA in TKA and the preoperative CA should be restored successfully.

The effects of residual hip deformity on coronal alignment of the lower extremity in patients with unilateral slipped capital femoral epiphysis.

PurposeThe aim of our explorative study was to compare the differences in the coronal alignments of the hip, knee and ankle on the slip side and non-slip sides in patients with slipped capital femoral epiphysis (SCFE).MethodsThe study group consisted of 28 patients. On the full-length standing radiographs, measurements of articulo-trochanteric distance (ATD), neck-shaft angle (NSA), femoral offset, hip-knee-ankle axis, femur-tibial angle, mechanical axis deviation ratio (MAD-r), anatomical medial proximal femoral angle (aMPFA), mechanical lateral proximal femoral angle (mLPFA), anatomical lateral distal femoral angle (aLDFA), mechanical lateral distal femoral angle (mLDFA), knee joint line congruency angle, mechanical medial proximal tibial angle (mMPTA), mechanical lateral distal tibial angle (mLDTA), ankle joint line orientation angle (AJOA), and leg length discrepancy (LLD) were performed. The data from the slip side were compared with those from the non-slip side.ResultsAt skeletal maturity, there were significant differences between the slip side and non-slip side in ATD (p <0.001), NSA (p <0.001), MAD-r (p <0.001), aMPFA (p <0.001), aLDFA (p = 0.03), mLDFA (p = 0.04), mLDTA (p = 0.02), AJOA (p <0.001) and LLD (p<0.001).ConclusionResidual deformity in the proximal femur after epiphyseal slip and premature epiphysiodesis could cause changes in the coronal alignment of the lower extremity. We can add lower extremity alignment examination to follow-up protocol to rule out secondary problems in patients with SCFE.Level of EvidenceLevel III, retrospective comparative study

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.

Changes in Hip, Knee, and Ankle Coronal Alignments After Total Hip Arthroplasty With Transverse Femoral Shortening Osteotomy for Unilateral Crowe Type IV Developmental Dysplasia of the Hip

BackgroundTo investigate changes in lower extremity coronal alignment in patients with unilateral Crowe type IV developmental dysplasia of the hip who underwent total hip arthroplasty with transverse femoral shortening osteotomy. MethodsWe reviewed the preoperative and 1-year postoperative full-length lower extremity radiographs of 25 patients. Femoral offset (FO), mechanical hip-knee-ankle angle, anatomical axis, mechanical axis deviation (MAD), mechanical lateral proximal femoral angle, anatomical medial proximal femoral angle, mechanical lateral distal femoral angle, anatomical lateral distal femoral angle, knee joint line congruency angle, mechanical medial proximal tibial angle, mechanical lateral distal tibial angle, ankle joint line orientation angle, tibial plafond talus angle, extremity length, and pelvic obliquity were measured on both the operative and nonoperative sides. ResultsPostoperatively, there were significant changes in FO (P = .001), hip-knee-ankle angle (P = .004), MAD (P = .016), mechanical lateral proximal femoral angle (P = .001), anatomical medial proximal femoral angle (P = .012), mechanical lateral distal femoral angle (P = .043), and ankle joint line orientation angle (P = .012) on the operative side. Only MAD (P = .035) changed significantly on the nonoperative side. ConclusionModification of FO and reconstruction of hip joint anatomy led to neutralization of knee and ankle valgus alignment. Effects on the nonoperative side were minimal.

Comparison of anatomical parameters of cam femoroacetabular impingement to evaluate hip joint models segmented from CT data

Subject-specific anatomical finite element models obtained from three-dimensional (3D) segmentation have the potential to provide great insights into the pathomechanisms of femoroacetabular impingement (FAI). Still, the accuracy of the geometries used to construct these models needs to be evaluated. To this aim, we segmented 54 (n = 54; age = 34 ± 7 years; BMI = 26 ± 4 kg/m2) hip joint models from subject-specific computed tomography (CT) images, and measured multiple anatomical parameters (axial alpha angle, radial alpha angle, femoral head–neck offset, femoral neck–shaft angle, medial proximal femoral angle, femoral torsion, acetabular version and centre–edge angle) from both the multiplanar images and the 3D models, to assess the intraobserver, interobserver and intermethod reliabilities. We implemented a method to ensure that anatomical characteristics from segmented models were representative of original CT data. Observations from both CT data and 3D models demonstrated strong to near-perfect intraobserver, interobserver and intermethod agreements (p < 0.01). Bland–Altman plots indicated a slight discrepancy when assessing the asymptomatic FAI population, where planar CT images possibly did not capture the full depth of the cam deformity and underestimated geometric parameters. We indicated possible discrepancies to expect when segmenting hip joint models for clinical evaluation and finite element modelling, notably when observing femoral head–neck offset.

Differences in anatomical parameters between the affected and unaffected hip in patients with bilateral cam-type deformities

BackgroundIt is still unclear why many individuals with bilateral cam deformities demonstrate only unilateral symptoms of femoroacetabular impingement, thus symptoms may be attributed to additional anatomical parameters. The purpose was to examine patients with bilateral cam deformities, with unilateral symptoms, and compare anatomical hip joint parameters between their affected (symptomatic) hip and their contralateral, unaffected (asymptomatic) hip. MethodsTwenty participants (n=20) with unilateral symptoms, but bilateral cam deformities, underwent CT imaging to measure their affected and unaffected hip's: axial and radial alpha angles, femoral head–neck offset, femoral neck-shaft angle, medial proximal femoral angle, femoral torsion, acetabular version, center-edge angle; and a physical examination (hip flexion, straight-leg raise, internal rotation, external rotation) to ascertain clinical signs. FindingsThe affected hips demonstrated limited motions during physical examination, compared with unaffected hips (effect size=0.550 to 0.955). The affected hips had significantly lower femoral neck-shaft angles (mean 125° (SD 3)) and lower medial proximal femoral angles (mean 79° (SD 4)), compared with the unaffected hips (mean 127° (SD 3), P=0.001, effect size=0.922; and mean 81° (SD 4), P=0.011, effect size=0.632; respectively). There were no differences in cam deformity parameters (axial and radial alpha angles, femoral head–neck offset), femoral torsion, acetabular version, and center-edge angle, between affected and unaffected hips. InterpretationA decreased femoral neck-shaft angle or medial proximal femoral angle can be implemented as a diagnostic predictor, to determine which hip may be at a greater risk of developing early symptoms.

Patient-specific anatomical and functional parameters provide new insights into the pathomechanism of cam FAI.

Femoroacetabular impingement (FAI) represents a constellation of anatomical and clinical features, but definitive diagnosis is often difficult. The high prevalence of cam deformity of the femoral head in the asymptomatic population as well as clinical factors leading to the onset of symptoms raises questions as to what other factors increase the risk of cartilage damage and hip pain. The purpose was to identify any differences in anatomical parameters and squat kinematics among symptomatic, asymptomatic, and control individuals and if these parameters can determine individuals at risk of developing symptoms of cam FAI. Forty-three participants (n = 43) were recruited and divided into three groups: symptomatic (12), asymptomatic (17), and control (14). Symptomatic participants presented a cam deformity (identified by an elevated alpha angle on CT images), pain symptoms, clinical signs, and were scheduled for surgery. The other recruited volunteers were blinded and unaware whether they had a cam deformity. After the CT data were assessed for an elevated alpha angle, participants with a cam deformity but who did not demonstrate any clinical signs or symptoms were considered asymptomatic, whereas participants without a cam deformity and without clinical signs or symptoms were considered healthy control subjects. For each participant, anatomical CT parameters (axial alpha angle, radial alpha angle, femoral head-neck offset, femoral neck-shaft angle, medial proximal femoral angle, femoral torsion, acetabular version) were evaluated. Functional squat parameters (maximal squat depth, pelvic range of motion) were determined using a motion capture system. A stepwise discriminant function analysis was used to determine which of the parameters were most suitable to classify each participant with their respective subgroup. The symptomatic group showed elevated alpha angles and lower femoral neck-shaft angles, whereas the asymptomatic group showed elevated alpha angles in comparison with the control group. The best discriminating parameters to determine symptoms were radial alpha angle, femoral neck-shaft angle, and pelvic range of motion (p < 0.001). In the presence of a cam deformity, indications of a decreased femoral neck-shaft angle and reduced pelvic range of motion can identify those at risk of symptomatic FAI.

The normal radiological anteroposterior alignment of the lower limb in children.

The development of reconstructive surgery of the lower limbs aimed at multilevel correction demands a precise knowledge of the physiological variations in general radiological parameters of the lower limbs in children of various age groups. It is crucial in systemic skeletal diseases, when deformities affect limbs and the surgeon does not have an intact limb as a reference. The aim of this retrospective study was to establish the normal radiological values of lower limb parameters used in the surgical correction of deformities in children of various age groups. Teleradiographs of the lower limbs taken in children with unilateral congenital or posttraumatic deformity were retrospectively reviewed. Weight-bearing full-length anteroposterior radiographs of the entire lower extremities were taken in a standing position. The study involved 215 extremities of 208 children (93 girls and 115 boys); the ages ranged from 2 years 1 month to 15 years 11 months old. Key variables included the anatomic medial proximal femoral angle (aMPFA), anatomic lateral distal femoral angle (aLDFA), anatomic medial proximal tibial angle (aMPTA), anatomic lateral distal tibial angle (aLDTA), mechanical axis deviation (MAD), the angle formed by the femoral anatomical axis and the mechanical axis of the lower limb. The means and dynamics of variations, standard deviations (SD) and 95% confidence intervals of each parameter were calculated for each age and gender group. Simple regression analysis was performed to determine the relationship between the patient's age and the magnitude of aMPFA, aLDFA, aMPTA and aLDTA. Simple regression analysis showed a significant inverse correlation between patient age and the magnitude of aMPFA: the correlation coefficient was -0.77. A statistically significant inverse correlation between the MAD and the angle between the anatomic femoral axis and mechanical limb axis was found: the correlation coefficient was -0.53. In general, the received values were concordant to results of other studies. It concerned the MAD, aLDFA, aMPTA and angle between the mechanical limb axis and anatomic femoral axis. This is the first chronological evaluation of aMPFA and aLDTA from a relavively large series of patients. These normative data should be taken into consideration when evaluating lower limb alignment in children or applied in practice for planning and evaluation of the quality of surgical correction of complex deformities.

Does Femoral Rotation Influence Anteroposterior Alpha Angle, Lateral Center-edge Angle, and Medial Proximal Femoral Angle? A Pilot Study

Femoral rotation on AP radiographs affects several parameters used to assess morphologic features of the proximal femur but its effect on femoroacetabular impingement parameters remains unknown. We therefore evaluated and characterized the potential effect of femoral rotation on (1) AP alpha angle, (2) lateral-center edge angle (LCEA), and (3) medial proximal femoral angle (MPFA) on AP hip radiographs. We took seven AP hip radiographs at intervals of successive femoral rotation on a single dry, cadaveric specimen: 60°, 40°, and 20° internal rotation; 0° neutral/anatomic rotation; and 20°, 40°, and 50° external rotation. The AP alpha angle, LCEA, and MPFA were measured on all radiographs by two independent evaluators. Within the range of femoral rotation studied, the AP alpha angle ranged from 39° to 62°, the LCEA from 25° to 35°, and the MPFA from 70° to 115°. MPFA and AP alpha angle showed a linear relationship with femoral rotation. Each additional degree of internal rotation produced a reciprocal reduction of the MPFA by 0.36° and the AP alpha angle by 0.18° and vice versa in external rotation. The LCEA, especially within the internal rotation range, showed minimal variation. These changes in radiographic parameters emphasize the importance of femoral rotation and patient positioning. We recommend radiographs be evaluated for excessive femoral rotation or nonstandardized positioning before interpretation for diagnostic and treatment implications. It may be prudent to repeat radiographs in these circumstances or, when standardized positioning is not feasible, proceed toward advance imaging.

Predictors of progression of osteoarthritis in femoroacetabular impingement

Although the association between femoroacetabular impingement and osteoarthritis is established, it is not yet clear which hips have the greatest likelihood to progress rapidly to end-stage disease. We investigated the effect of several radiological parameters, each indicative of a structural aspect of the hip joint, on the progression of osteoarthritis. Pairs of plain anteroposterior pelvic radiographs, taken at least ten years apart, of 43 patients (43 hips) with a pistol-grip deformity of the femur and mild (Tönnis grade 1) or moderate (Tönnis grade 2) osteoarthritis were reviewed. Of the 43 hips, 28 showed evidence of progression of osteoarthritis. There was no significant difference in the prevalence of progression between hips with initial Tönnis grade 1 or grade 2 osteoarthritis (p = 0.31). Comparison of the hips with and without progression of arthritis revealed a significant difference in the mean medial proximal femoral angle (81 degrees vs 87 degrees, p = 0.004) and the presence of the posterior wall sign (39% vs 7%, p = 0.02) only. A logistic regression model was constructed to predict the influence of these two variables in the development of osteoarthritis. Mild to moderate osteoarthritis in hips with a pistol-grip deformity will not progress rapidly in all patients. In one-third, progression will take more than ten years to manifest, if ever. The individual geometry of the proximal femur and acetabulum partly influences this phenomenon. A hip with cam impingement is not always destined for end-stage arthritic degeneration.