Normal Neck-shaft Angle Research Articles

Effect of the Initial Deformity in the Coronal Plane on Postoperative Outcome of Proximal Humeral Fractures.

There is currently no consensus on proximal humerus fractures with an initial deformity in the coronal plane who are better off with plates or nails, so we designed this study. To compare the effect of the initial deformity in the coronal plane of proximal humerus fractures on postoperative outcomes, we compare the maintenance of reduction in procedures utilizing plates and nails, and analyzed the subsequent occurrence of complications to explore whether the initial deformity should dictate the fixation approach. The clinical data of patients with proximal humerus fractures who were hospitalized and underwent surgical treatment in our hospital from January 2016 to December 2020 were reviewed. Postoperative functional scores (American Shoulder and Elbow Surgeons, ASES; Constant-Murley Score, CMS), Neck-shaft angle (NSA), Quality of fracture reduction, Deltoid Tuberosity Index (DTI), and complications were compared among cases with initial varus, normal, or valgus deformities. We included 131 patients, 56 males and 75 females, with a mean age of 60.89 ± 5.53 years (range 50-76) and a mean follow-up duration of 16.63 ± 6.78months (range 12-48). Of these, 29 cases had initial varus displacement, 71 had a normal NSA, and 31 had initial valgus displacement. Seventy-five were treated with a locking plate and 56 with a nail. After open reduction and internal fixation, the NSA was restored to normal (-135°) in all patients in all groups (P > 0.05). There was a significant difference in NSA changes at the last follow-up; 2.93° ± 2.12° in the varus group, 1.77° ± 1.18° in the normal group, and 2.32° ± 1.64° in the valgus group, with the highest change occurring in the varus group. There was no significant difference in the range of motion or functional scores including ASES and CMS among the three groups (P > 0.05). The complication rate of 20.7% in the varus group was significantly higher than the complication rates of 12.7% in the normal and 12.9% in the valgus groups (P < 0.05). While proximal humerus fractures with initial coronal displacement (varus, normal, and valgus) show similar postoperative functional outcomes, varus fractures have a higher rate of complications. The nail provides better maintenance of reduction than the locking plate, especially in varus fractures.

Influence of neck shaft angle of humerus in prosthesis design

BackgroundA better understanding of the proximal humerus is essential for anatomical reconstruction of the glenohumeral joint during prosthetic replacement. The neck-shaft angle is critical for correct calcar screw positioning when fixing a proximal humeral fracture with a locking plate. It's essential for exact implant placement and treatment of any soft-tissue or bone pathology. Improper implants cause discomfort and post-operative complications, therefore understanding the humeral neck shaft angle is fundamental in the design and manufacturing of prostheses. This study looked into the necessity regional data of the humeral neck shaft angle (NSA) and its importance in shoulder prosthesis manufacturing. MethodThis cross-sectional investigation was conducted on 300 dry cadaveric humeri of unknown gender and age that were free of damage or deformity. The Goniometer was used to measure the neck shaft angle. The data was analysed using SPSS software. The standard deviation and mean were calculated. The statistical difference between the right and left humeri was assessed using the students' t' test. ObservationsThe NSA of the humerus was 131.265.82° on average. The NSA mean values were substantially higher on the right side. A statistically significant difference between the right and left humeri was revealed by a P value of 0.001. ConclusionSuccess of the shoulder arthroplasty demands anatomical reconstruction of the normal neck-shaft angle of the humerus. Racial variations in the morphometry of the neck-shaft angle needs to be considered in prosthesis design.

Morphometric Study of Proximal Femur and its Applications in Prosthesis Designing: A Cross-sectional Study from Western India

Introduction : The hip joint is subjected to daily stresses as it bears the weight of the upper body. Osteoarthritis of the hip may cause irreversible damage. Proximal geometry of the femur, like neck-shaft angle and torsion is important in designing prostheses for a specific population. Most of the prostheses manufacturers follow the Western parameters as there is a scarcity of data in the Indian context. Aim: To analyse the normal Neck-Shaft Angle (NSA) and torsion of the femur in the Indian population. Materials and Methods: This cross-sectional analytical study was carried out in a total of 300 dried femora (150 right and 150 left) of unknown age and gender without any defect or damage during a period of 2.6 years (June 2019 to December 2021) in Sumandeep Vidyapeeth University, Gujarat, India. The NSA and the angle of femoral torsion was measured using a Goniometer. Mean and standard deviation were calculated. Student’s t-tests was applied to ascertain the statistical difference between right and left femur. Results: The average NSA was 128.55±6.99°. The mean values were 130.70±6.03° and 126.41±7.22° on right and left sides respectively with statistically significant difference (p-value&lt;0.0001). The average femoral torsion was found to be 16.43±2.34°. On the left side, it was 16.43±2.31° and 16.43±2.36° on the right side with No statistically significant difference was found between right and left femorae (p-value=1.00). Conclusion: The accuracy and success of the hip replacement surgery demands complete knowledge of the morphometry of the proximal femur which is highly specific among the races, region and gender. The present study provides the normal morphometry of the proximal femur of Indian population.

Factors Influencing the Varus Deformity of Humeral Head in Proximal Humerus Fractures and Its Relation to Functional Outcome.

Fractures of the proximal humerus represent approximately 4% of all fractures and 26% of humerus fractures. Proper reduction, stable internal fixation and early initiation of physiotherapy help to achieve a good functional outcome. Aim of this study was to evaluate varus fixation/malunion of proximal humerus fractures and its relation to functional outcome. We retrospectively evaluated 32 patients with proximal humerus fractures who were surgically treated between 2015 and 2017 at tertiary care hospital. We divided the patients into three groups on the basis of the neck-shaft angle as valgus group, normal group and varus group to observe the influence of neck-shaft angle on efficacy. Patients were evaluated for functional outcome using the Constant-Murley score. Two-part fractures had better functional outcome (Constant score = 75.15) compared to three parts with the moderate functional outcome (Constant score = 68.81) and the four-part fracture had poor functional outcome (Constant score = 52.66). After 6months of follow-up, 13 patients had a neck-shaft angle of less than 126°. The functional outcome is significantly better among patients with normal neck-shaft angle and had a mean Constant score of 76.63 as compared to patients with varus deformity had a mean Constant score 60 (p = 0.001). 10 patients did not have medial support, in which 08 patients had neck-shaft angle less than 126° and 2 had a normal neck-shaft angle. High fracture comminution, improper restoration of medial continuity causes varus deformity of the humeral head and it leads to poor functional outcome. The small sample size is the limitation of our study.

A morphometric study of femoral length, anterior neck length, and neck-shaft angle in dry femora: A cross-sectional study

Background: As the environment plays an important role in the development, the regional variation of the femur bone is influenced by geographical area, sex, stature, and heredity. In the present study, measurements on the adult human dry femora have been carried out. The knowledge of variations in the parameters of dry femora will help the orthopedicians and also assist prosthetists to design a suitable prosthesis for restoration of normal neck-shaft angle (NSA) and will also help forensic anthropologists to determine the sex.Objectives: The objectives of this present study is to determine the various parameters including femoral length, anterior neck length, and NSA of femur among Indian population and to compare them with the data available in the literature.Materials and Methods: This study was done on 100 adult dry human femora of unknown age and sex (50 right side and 50 left side), collected from the Department of Anatomy and students of J. N. Medical College, Belagavi, Karnataka, India.Results: In the present study, the length of femur ranged from 336 to 485 mm with the mean of 413.15 mm. Length of right femur ranged from 346 to 472 mm with the mean of 409.4 mm and that of left femur ranged from 336 to 485 mm with the mean of 416.9 mm. The anterior neck length of femur ranged from 20 to 40 mm with the mean of 28.8 mm. The anterior neck length of right femur ranged from 20 to 38 mm with a mean of 28.8 mm and that of left femur ranged from 21 to 40 mm with the mean of 28.8 mm. The NSA ranged from 115° to 140° with the mean of 127.21°. In the right femur, it ranged from 115° to 137° with the mean of 126.78°, and in the left femur, it ranged from 119° to 140° with the mean of 127.64°.Conclusions: There was no comparative difference between the values of right and left sides for all parameters. The values observed for all three parameters were greater in the Western world than in the present study, and it was concluded that Western people were taller and heavier than the average Indians, thus showing the regional variation. Clinically, this study plays an important role for orthopedicians and prosthetists to build suitable prostheses for Indians.

Radiographic Classification of Coronal Plane Femoral Deformities in Polyostotic Fibrous Dysplasia

Fibrous dysplasia of bone is a skeletal dysplasia with a propensity to affect the femur in its polyostotic form, leading to deformity, fracture, and pain. The proximal femur is most commonly involved with a tendency to distal progression, thereby producing the typical shepherd's crook deformity. However, there are few data on the spectrum and progression of femoral deformities in polyostotic fibrous dysplasia. The purposes of this study were (1) to develop a radiographic classification for polyostotic fibrous dysplasia; (2) to test this classification's intra- and interobserver reliability; and (3) to characterize the radiographic progression of polyostotic fibrous dysplasia in a population of patients with the condition who were treated with a variety of approaches at several centers. We retrospectively reviewed radiographs of 127 femurs from 84 adult patients affected by polyostotic fibrous dysplasia. Fifty-nine femurs had undergone one or more operations. The radiographs were evaluated in the coronal plane for neck-shaft angle and angular deformities along the whole femoral shaft down to the distal epiphysis. Four observers evaluated each film two times at intervals; intra- and interobserver reliability testing was performed using the kappa statistic. Eighty-nine femurs (70%) were available for followup to evaluate for progression at a mean of 10 years (range, 6-20 years). Six reproducible patterns of deformity were identified in both untreated and operated femurs: type 1 (24%), normal neck-shaft angle with altered shape of the proximal femur; type 2 (6%), isolated coxa valga with neck-shaft angle > 140°; type 3 (7%), isolated coxa vara with neck-shaft angle < 120°; type 4 (20%), lateral bowing of the proximal half of the femur associated with normal neck-shaft angle; type 5 (14%), like in type 4 but associated with coxa valga; and type 6 (29%), like in type 4 but associated with coxa vara. Interobserver and intraoberver kappa values were excellent, ranging from 0.83 to 0.87. In 46 of the 89 femurs (52%) for which longitudinal radiographic documentation was available, there was progressive worsening of the original deformity, although the pattern remained the same; types 1 and 2 tended not to progress, whereas types 3 to 6 did. A reproducible radiographic classification of polyostotic fibrous dysplasia-associated femoral deformities is proposed, which can serve as a tool for assessing and treating these deformities. After reviewing the radiographs of 127 femurs, we identified six reproducible patterns of femoral deformities. Level III, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.

Clinical benefits of the reconstruction of the normal humeral neck-shaft angle for displaced proximal humerus fractures treated with locking plates

Objective To investigate the normal humeral neck-shaft angle (NSA) and the clinical benefits of reconstructing normal NSA for displaced proximal humerus fractures treated with locking plates.Methods Humeral NSA was measured in 382 normal adults.A retrospective analysis was conducted on 128 patients with proximal humerus fractures treated with locking plates from June 2006 to February 2011.The postoperative NSA of the affected shoulders was measured,and all cases were divided into 3 groups based on bilateral 95％ reference range of the normal NSA: varus group in which the postoperative NSA was smaller than the lower limit of the bilateral 95％ reference range,normal group in which the postoperative NSA was within the bilateral 95％ reference range,and valgus group in which the postoperative NSA was larger than the upper limit of the bilateral 95％ reference range.The changes of the NSA,Constant shoulder scores,visual analog scale (VAS) score and complications were documented for analysis.Results The mean normal NSA was 136.1°± 4.5 °and the bilateral 95％ reference range was 127.2 ° to 144.9 °.All patients were followed up for 6 to 32 months.There were 29 patients in varus group,90 in normal group and 9 in valgus group.For the 3 groups,at final follow-up,the mean Constant shoulder score was 70.3,77.2 and 73.2,respectively; the mean VAS score was 2.8,1.8 and 2.1,respectively; the mean varus angle was 4.2°,1.6° and 3.1°,respectively; and the incidence of complications was 34.5％,14.4％ and 22.2％,respectively.The results of the normal group were better than those of varus group in terms of Constant shoulder score,VAS score,and incidence of complications.Conclusion Reconstruction of the normal NSA is crucial to the good clinical outcomes.Patients with initial varus malreduction have a higher incidence of complications,such as secondary loss of reduction. Key words: Humeral fractures; Fracture fixation, internal; Treatment failure

Effect of a Variable Prosthetic Neck-Shaft Angle and the Surgical Technique on Replication of Normal Humeral Anatomy

Replicating the normal anatomy of the shoulder is an important principle in the design of prosthetic devices and the development of surgical techniques. In this study, we used a three-dimensional surgical simulation to compare the abilities of an adjustable neck-shaft angle prosthesis and a fixed neck-shaft angle prosthesis to restore the normal geometry of the proximal part of the humerus. A total of 2058 cadaveric humeri were measured to define the normal distribution of neck-shaft angles. Thirty-six humeri were selected to represent a wide variation in neck-shaft angles, and computed tomographic scans with three-dimensional reconstruction were made of these specimens. With use of a three-dimensional computer surgical simulator, the humeral head was then cut at the anatomic neck to replicate a normal neck-shaft angle and version or it was cut at a fixed 135 degrees angle with anatomic version. The anatomy of an adjustable-angle prosthesis and that of a fixed-angle prosthesis of the same design were both compared with native humeral anatomy in three dimensions. The average neck-shaft angle of the 2058 humeri was 134.7 degrees (range, 115 degrees to 148 degrees), and the angle was between 130 degrees and 140 degrees in 77.84% of the humeri. In the setting of a high varus or valgus neck-shaft angle, an adjustable-angle prosthesis allowed optimal reconstruction when the humeral head was cut along the anatomic neck and allowed a standard and consistent surgical technique with use of anatomic landmarks. A fixed-angle prosthesis also replicated the anatomic center of rotation, tuberosity-head height, and head volume if the surgical procedure was altered to adapt to variations in humeral anatomy. There was no significant difference in anatomic parameters between the two types of prostheses, except that in all cases the head thickness was decreased when a fixed-135 degrees-angle prosthesis was used in a humerus with a high valgus or high varus neck-shaft angle, resulting in a smaller articular arc and percent articular surface match. This study demonstrates the ability of both an adjustable and a fixed neck-shaft angle prosthesis to replicate humeral anatomy. However, the fixed-angle device requires specific modifications of the surgical technique to accommodate the specific prosthetic design and optimize the surgeon's ability to replicate normal anatomic parameters in humeri with an extreme neck-shaft angle.

Osteochondroplasty of the femoral head in hip reconstruction for type II late sequelae of septic arthritis: A preliminary report

To suggest different procedures tailored for hip reconstruction in type II late sequelae of septic arthritis. The severely deformed subluxated or dislocated femoral head is reshaped in accordance to radiographic and on-table assessment (osteochondroplasty). Sixteen hips in 13 patients (three bilateral) were the subject of this study. They were all affected during incubation in the first few weeks after birth. Age at operation was in the range 2-12 years (average 5.3). The main complaint was instability, stiffness during walking and the inability to sit comfortably, limb length discrepancy, and mild pain on walking. Preoperatively, the range of motion was limited to a certain degree in different directions in all cases. Plain radiography, computed tomography (CT), or multi-slice CT with reconstruction 3D views were of benefit in analyzing the problem preoperatively. Magnetic resonance imaging (MRI) was performed for selected cases after 2 years to test for the viability of the femoral head. A modified approach was used to adequately expose the iliac bone, the hip, and the upper third of the femur. Meticulous dissection to preserve the amalgamated capsule and a well-planned capsulotomy for later adequate capsulorrhaphy is essential. Debridement to clear the acetabulum from intra-articular fibrosis is attempted prior to acetabular reconstruction (Salter, Dega, or triple pelvic osteotomy). Head and neck reconstruction (osteochondroplasty) is performed according to the nominated topography of the deformed head (beard, collared, staghorn, etc.). A carefully planned reshaping in a manner not disturbing the superior weight bearing articulating surface with the acetabulum will allow easy containment in the reconstructed acetabulum. Associated subluxation or dislocation will dictate adequate shorting with femoral cuts inclined in a manner bringing the impinging overgrown greater trochanter down, achieving a near to normal neck shaft angle. According to the criteria proposed by Hunka et al. (Clin Orthop Relat Res 171:30-36, 1982), a satisfactory result is considered when a stable pain-free hip is achieved with flexion arc >70 degrees and flexion contracture <20 degrees . This was true in 13 hips. It appears that better results are achieved in younger children with minimal intra-articular adhesions limiting hip movements, and with less destruction of the articular cartilage. A final improvement in the range of movement should not be expected before 6-12 months. Intensive physiotherapy to improve postoperative stiffness is required. The proposed reconstruction procedure for reshaping the deformed femoral head (osteochondroplasty) is a salvage attempt that achieved a more or less mobile painless stable hip joint besides restoring the normal anatomical relationship, should total hip replacement (THR) be needed in the future.

The Anterior and Medial Reduction of Intertrochanteric Fractures: A Simple Method to Obtain a Stable Reduction

This article describes a simple method using anterior and medial bone contact of the distal shaft piece to obtain a stable reduction for displaced intertrochanteric fractures of the hip. The technique is based on the observation that the anterior pathoanatomy of the intertrochanteric hip fracture involves a noncomminuted fracture plane that can be placed into contact. This reestablishes a normal neck shaft angle and prevents excessive collapse of the fracture site. The maneuver is described in the context of the fracture pathoanatomy and the use of a fracture table.

The Modified Tonnis Triple Pelvic Osteotomy in the Young Adult - Early Results

Acetabular dysplasia may present as previously undiagnosed or as a sequel to treated DDH in a young adult, with a natural history of subsequent development of early osteoarthritis. Patients with acetabular dysplasia, a normal neck shaft angle, no significant leg length inequality and who demonstrate congruency at arthrogram are considered suitable for realignment pelvic osteotomy. We report the results of 15 young adults who underwent a modified Tonnis triple osteotomy with a mean 22-month follow-up. The modification was that the ischial osteotomy was performed through a groin incision. The only common complication was the requirement of catheterisation post-operatively (60%). There were no infections. There was one delayed union but no non-unions. One patient developed a deep vein thrombosis. All patients reported an improvement in their symptoms and level of activity, with a mean post-operative Harris hip score of 92. All showed an improved centre-edge angle of 28° (mean increase of 18°) and acetabular angle of 37° (mean decrease of 13°). The early results of this procedure show it to be a safe and useful option to delay the natural history of early osteoarthritis in the young adult.

Prediction of the femoral neck-shaft angle from the length of the femoral neck.

A total of 171 adult South Indian femora, devoid of gross pathology, are used to measure the neck-shaft angle, length of the neck, intertrochanteric apical axis length, maximum vertical diameter of the head, kinematic radius, and maximum femoral length. The neck-shaft angle ranges from 120 degrees to 136 degrees with a mean of 126.7 degrees and no significant side difference. The angle significantly and positively correlates with neck length, intertrochanteric apical axis length, kinematic radius, and minimum femoral length (P < 0.001) but not with the vertical diameter of the head. Regression equations for the neck-shaft angle against the correlated parameters are derived but only that against the length of the neck is strongly significant. From those correlations, 1) the neck-shaft angle can be estimated from a proximal femoral fragment, and 2) the required size of the length of the neck can be determined to design prostheses for the restoration of normal neck-shaft angle. Further, any estimated defective angle can be of help for forensic identification of an individual with pathological changes leading to an abnormal gait.

The Hip Joint in Down??s Syndrome

Clinical and roentgenographic examination of the hip was performed in 114 patients with Down's syndrome to study range of motion, roentgenographic anatomy, and incidence of hip pathology. The study found increased external rotation of the hip. Roentgenographic studies demonstrate that, in comparison with a normal acetabulum, the acetabulum of a patient with Down's syndrome is deep, more horizontally placed, and has increased anteversion. The proximal femur of a patient with Down's syndrome has a normal neck-shaft angle and a moderate increase in anteversion. Of the patients, 7.9% had some hip abnormality, including dysplasia, dislocation, avascular necrosis, or slipped capital femoral epiphysis.

Paralytic hip instability in poliomyelitis.

A retrospective study was made of the results of surgical treatment of subluxation or dislocation of the hip in patients who had suffered from poliomyelitis. Good results were achieved in 46% and satisfactory results in 24%. The key factors for success are muscle balance, the femoral neck-shaft and anteversion angles, and the acetabular geometry. Iliopsoas transfer can augment the hip abductor power by an average of one MRC grade. Varus derotation femoral osteotomy is important to re-establish a normal neck-shaft angle and anteversion. The results of pelvic osteotomy are variable and the importance of a posterior acetabular defect is emphasised.

The development of a computational stress analysis of the femoral head. Mapping tensile, compressive, and shear stress for the varus and valgus positions.

Using a computer-based, two-dimensional finite-element analysis which has wide application to problems involving the hip joint, alterations in the distribution of stress in the femoral head consequent to varus and valgus osteotomy were studied. The mathematical model used in this analysis incorporated experimentally measured spatial variations in the stiffness of the bone of the femoral head and neck. These variations led to patterns of load transmission that were strikingly different from those in a homogeneous material. Because of their lower stiffness, the central region of the head and the medullary region of the neck make very little contribution to weight-bearing, regardless of the orientation of the femoral head. In the neutral configuration (normal neck-shaft angle), the lateral cortex of the neck is in slight tension, while the medial cortex is under strong compression and provides the support for the over-all load on the joint. With increasing valgus angulation, the bending component of the joint load disappears progressively, and when the valgus angulation is 30 degrees in excess of normal essentially equal compressive stresses prevail in both cortices. Varus osteotomy exaggerates the bending component relative to the compressive component of the load. The computed stress patterns in the femoral head and neck for the normal neck-shaft angle show elevations of shear stress where the lateral epiphyseal artery enters and branches within the femoral head. This finding may be significant since this region is the area at risk of infarction in both Legg-Perthes disease in children and idiopathic aseptic necrosis in adults. Since a 30-degree varus angulation induces tensile stresses in the lateral cortex of the neck that are increased fourfold above those for the neutral configuration, it is postulated that force transmitted through the femur when the hip is in abduction could produce shear fractures of the bone in the region of the central branch of the lateral epiphyseal artery and thus occlude this vessel and initiate aseptic necrosis of the femoral head.

Varus-Producing and Derotational Subtrochanteric Osteotomy in the Treatment of Congenital Dislocation of the Hip

The analysis of the results to date of fifty-nine varus osteotomies with or without derotation to correct anteversion done for congenital dislocation and subluxation of the hip indicates that the following advantages are obtained: 1. The procedure permits complete concentric reduction of the femoral head; 2. The dynamic and static forces maintaining reduction of the hip are improved; 3. As a result of advantages 1 and 2, greater stability is obtained and maintained: 4. The tendency to subsequent subluxation is reduced (there have been no redislocations in this series): 5. The incidence of aseptic necrosis is decreased; 6. The surgically produced varus position—a neck-shaft angle 90 to 100 degrees—tends with growth to return to a normal neck-shaft angle; 7. The varus position is easily produced at the time the derotation osteotomy is done to correct anteversion: 8. Complications are minimum; 9. The necessity for further surgical procedures is reduced.