Idiopathic Increased Anteversion of the Femoral Neck: Radiological and Clinical Study in Non-operated and Operated Patients

The development of femoral neck angles in children with idiopathic increased anteversion was investigated. The anteversion (AV) angle in 16 non-operated patients (n = 32) decreased from a mean of 45 degrees at the age of 7.3 years (median) to 31 degrees at the age of 15.7 years. The neckshaft (CCD) angle remained unchanged.

A subtrochanteric derotational osteotomy was performed in 24 patients (n = 48) aged 7.7 years (median). The AV angle was corrected from 47 to 3 degrees, and the CCD angle from 134 to 124 degrees. At follow-up at the age of 16.5 years the AV and the CCD angles had increased to 14 and 135 degrees respectively. The internal rotation of the hip was increased to the same extent in the two patient groups. The degree of external rotation as well as total rotation was significantly larger in the non-operated patients compared to the patients who needed an operation.

At follow-up the rotational movements of the hip and the external torsion of the leg/foot were measured and compared with the corresponding measurements for a control group of 26 healthy subjects whose median age was 16.3 years. In the non-operated patients the internal rotation was reduced at a rate corresponding to the spontaneous reduction of the femoral anteversion, while the external rotation was unchanged. In the operated patients the rotational movements were normalized, as was the anteversion of the femoral neck. No differences in external torsion of the leg/foot were found in the three groups.

Based on these results we conclude that cases of idiopathic increased anteversion of the femoral neck are not corrected spontaneously as the child grows up. With a subtrochanteric derotational osteotomy slight overcorrection may be indicated, but simultaneous varus correction of the femoral neck seems to be unnecessary. The degree of external rotation of the hip determines gait symptoms in patients with increased femoral anteversion. No regular compensatory external torsion of the leg/foot develops during growth.     

Osteotomy for femoral anteversion. A prospective 9-year study of 52 children

Fifty-two children with increased femoral anteversion had bilateral derotational subtrochanteric osteotomies at a mean age of 7 years. They were followed prospectively until at least 15 years of age; the mean observation time was 9 years. They were a subset of 95 children whose 2-year results were reported in 1989. The mean increase of femoral anteversion after the osteotomy was 6 degrees (0.7 degrees per year) and of the neck-shaft angle 5 degrees. The CE angle did not increase. Although we at present practice a more restrictive attitude towards operation of increased femoral anteversion, our study showed that a derotational osteotomy is effective in eliminating the intoeing gait and associated complaints, and the hip angles change only moderately during the remaining period of growth.     

液晶数字显示角度仪在全髋关节置换术中的应用价值

目的:探讨在全髋关节置换术中使用液晶数字显示角度仪控制前倾角的应用价值。方法:回顾分析自2018年1月至2019年12月83例行初次全髋关节置换术的患者,其中男28例,女55例;年龄42~81(70.4±7.9)岁。股骨颈骨折63例,股骨头缺血性坏死20例。所有患者术中使用液晶数显角度仪控制髋臼杯假体的前倾角,术后采用CT扫描,测量髋臼杯的前倾角,两者进行比较,了解使用液晶数显角度仪的准确性。结果:术后CT测量提示患者的髋臼前倾角均位于Lewinnek提倡的安全区内,术中使用液晶数显角度仪测量髋臼杯的前倾角度中位数为14.20°(12.80~15.40)°,术后CT扫描测量的髋臼杯的前倾角中位数为14.20°(13.40~15.50)°,两者比较差异无统计学意义(Z=-1.725,P=0.085)。结论:应用液晶数显角仪器对术中控制髋臼杯的前倾角是一种准确可靠的方法,具有良好的辅助参考价值。     

Reducing the risk of dislocation after total hip arthroplasty: the effect of orientation of the acetabular component

Malposition of the acetabular component is a risk factor for post-operative dislocation after total hip replacement (THR). We have investigated the influence of the orientation of the acetabular component on the probability of dislocation. Radiological anteversion and abduction of the component of 127 hips which dislocated post-operatively were measured by Einzel-Bild-R?entgen-Analysis and compared with those in a control group of 342 patients. In the control group, the mean value of anteversion was 15 degrees and of abduction 44 degrees. Patients with anterior dislocation after primary THR showed significant differences in the mean angle of anteversion (17 degrees), and abduction (48 degrees) as did patients with posterior dislocation (anteversion 11 degrees, abduction 42 degrees). After revision patients with posterior dislocation showed significant differences in anteversion (12 degrees) and abduction (40 degrees). Our results demonstrate the importance of accurate positioning of the acetabular component in order to reduce the frequency of subsequent dislocations. Radiological anteversion of 15 degrees and abduction of 45 degrees are the lowest at-risk values for dislocation.     

The Frank Stinchfield Award: Morphologic features of the acetabulum and femur: anteversion angle and implant positioning.

Morphologic features of the hips, in particular those features germane to determination of acetabular and femoral anteversion angles and femoral head offset, were studied in 50 male and 50 female human skeletons with bilateral normal joints. Four distinct configurations were identified relative to the anterior acetabular ridge. The majority (121, 60.5%) were curved; 51 (25.5%) were angular; 19 (9.5%) were irregular; and nine (4.5%) were straight. The acetabular anteversion angle measured 19.9 degrees +/- 6.6 degrees (range, 7 degrees-42 degrees) and was significantly larger in females (21.3 degrees +/- 7.1 degrees) versus males (18.5 degrees +/- 5.8 degrees). The notch acetabular angle, which can be identified easily intraoperatively, was defined as the angle created at the intersection of a line from the sciatic notch along the posterior acetabular ridge and a line from the posterior to the anterior acetabular wall. This angle is almost perpendicular (89.0 degrees +/- 3.5 degrees) and, therefore, may provide an accurate estimate of acetabular anteversion during cup placement. Awareness of the anatomic differences between genders for acetabular anteversion angle, anterolateral bowing of the femur, and neck shaft angle may help reduce the relatively higher incidence of dislocation in females and may lead to different implant designs for male and female patients.     

查体测量与影像学测量股骨前倾角准确性的评价

[目的]评价临床查体测量、CT测量、术中实体测量三种股骨颈前倾角测量方法的准确性,并对其临床应用的意义进行探讨.[方法]选择87例股骨头坏死患者,术前分别行:全股骨CT扫描,采用Murphy法计算前倾角;术前查体测量前倾角;进行关节置换术时,在股骨实体上测量前倾角.对三种方法测量得到的结果进行相关性分析.[结果]术中测量前倾角平均值8.57°±8.91°,查体测量平均值9.06°±9.40°,CT测量平均值14.26°±8.40°.三组测量值的相关性分析:查体测量与术中测量组间相关系数R2=0.87 (P ＜0.05),CT测量与查体测量组间相关系数R2=0.79 (P ＜0.05),CT测量与术中测量组间相关系数R2 =0.81(P ＜0.05).[结论]临床查体测量前倾角结果较准确,在临床中可作为初步测量和异常筛查的方法.     

Anteversion of the acetabulum and femoral neck in early walking age patients with developmental dysplasia of the hip

Computed tomography measurements were made to quantify the relationship between the anteversion of the acetabulum and femoral neck in 27 early walking age patients (age range; 18-48 months) with developmental dysplasia of the hip. The centre-edge angle and acetabular index were measured in standard pelvis radiographs, and anteversion of acetabulum and femoral neck were measured by use of two-dimensional computed tomography in 25 complete dislocated, 19 subluxated and 10 unaffected hips (a total of 54 hips). The diagnosis of dysplasia, subluxation and complete dislocation of developmental hip dysplasia were determined radiographically using Ishida's criteria. There were statistically significant differences between the three groups for the centre-edge angle, the acetabular index, and acetabulum anteversion. There was no statistically significant difference between the three groups for femoral neck anteversion. The acetabular anteversion was found to be 13.4+/-2.8 degrees (mean+/-SD) in unaffected hips, 16.7+/-1.9 degrees in subluxated hips and 19.8+/-2.5 degrees in complete dislocated hips. There was statistically significant difference between the three groups, with a wide range of acetabular anteversion values noted in all groups (9-26 degrees ). The acetabular anteversion was increased on the dislocated side in each patient and we found no retroverted acetabulum. On the other hand there was no significant difference between the groups with regards to femoral neck anteversion. We conclude that confirming anteversion of the acetabulum and the femoral neck by two-dimensional computed tomography is needed in treatment planning of early walking age patients with developmental hip dysplasia.     

Ultrasound measurement of femur neck anteversion]

We introduce a simple method of sonographic determination of femoral neck anteversion in children with which the even difficult angels in terms of measurement, those up to 70 degrees, can be measured with sufficient reliability: The examination was done with a defined internal 40 degree rotation of the legs reached by a supporting wedge. We proved this method on 55 children's hips of which we already had an existing radiologic determination of the anteversion angle. Compared to the radiological results we found an average deviation of 3.6 degrees (standard deviation = 3.2).     

Rotational profile of lower extremities in bladder exstrophy patients with unapproximated pelvis: a clinical and radiologic study in children older than 7 years.

Fourteen patients (nine boys, five girls) with bladder exstrophy were analyzed radiologically and clinically. All were older than 7 years and had a pubic diastasis >2 cm. Anteroposterior and lateral center-edge angles were measured by direct radiography. Acetabular version, femoral anteversion, tibial torsion angles, and patellofemoral congruency angle were measured by computed tomography imaging. All were active with regard to their daily life and sports activities. The average foot-progression angle was +8 degrees . Spherical congruency was present in all hips, and none showed dysplasia. The average angle of acetabular version was apparently less than normal, but femoral anteversion angles were found to be increased. Increased external tibial torsion was observed in all patients. Twelve (71%) of 14 patients had positive congruence angles, the average being +6.1 degrees . Two patients had subjective complaints of patellofemoral instability. Increased femoral anteversion and external tibial torsion may lead to patellofemoral instability, and the bladder exstrophy patients should be followed up regarding this problem as well.     

Overgrowth and correction of rotational deformity in 12 femoral shaft fractures in 3-6-year-old children treated with an external fixator

We treated 11 young children (3-6 years old) who had uncomplicated femoral shaft fractures primarily with an external fixator. 9 children were available for follow-up and were evaluated for the amount of overgrowth and rotational deformity. All underwent a clinical examination and an MRI after mean 21 (13-25) months. The mean overgrowth was 0.4 (-0.3-1.1) cm and the anteversion angle showed a mean increase of 12 degrees, as compared to the contralateral femur. In 5 children with an anteversion angle difference of 10 degrees or more, a second MRI was done 4 years after the trauma. The mean anteversion angle difference of the femora in these 5 children had diminished from 15 degrees on the first MRI to 7.4 degrees on the second. 3 of the 5 children had a full correction of their rotational deformity. Growth did not correct the rotational deformity in the oldest child in this group.     

Clinical determination of femoral anteversion. A comparison with established techniques.

We evaluated femoral anteversion preoperatively in fifty-nine patients (ninety-one hips), using a clinical method that we developed, Magilligan radiographs, and computed tomographic scans. These measurements were then compared with values for anteversion that were obtained intraoperatively. To determine femoral anteversion clinically, the patient was placed in the prone position and the maximum lateral trochanteric prominence was related to the degree of internal rotation of the hip. Compared with computed tomographic scanning and Magilligan radiographic determination, the clinically determined anteversion correlated most closely (to within 4 degrees) with the amount measured at the time of the operation. The clinical method was found to be superior to radiographic techniques for determination of the degree of femoral anteversion in children who have not had a previous operation about the hip.     

Measurement of the acetabular cup anteversion on simulated radiographs

Widmer (J Arthroplasty 2004;19:387) reported a protractor for measuring the anteversion of acetabular cups on radiographs but with limited precision. We intended to improve its precision by trigonometric mathematics. We measured the anteversion of the acetabular cups on 336 simulated radiographs using aforementioned 2 methods. The anteversion measured by Widmer's protractor ranged from 7 degrees to 41 degrees (mean +/- SD = 28.0 degrees +/- 9.8 degrees), and our methods, 5 degrees to 51 degrees (27.7 degrees +/- 13.2 degrees). The mean +/- SD of error by Widmer's protractor was 5.2 +/- 2.5 degrees, and our protractor, 0.8 degrees +/- 0.8 degrees (Student t test, P b .0001). The interobserver study showed the difference between measurements less than 2 degrees for each method. Therefore, the smaller error of our method than that of Widmer implicated a potentially precise measurement of the anteversion (level of evidence: diagnostic study, level II).     

Change in the CCD angle and the femoral anteversion angle by hip prosthesis implantation]

PURPOSE: The aim of the present study was to measure and interpret the change of the collodiaphyseal (CCD) angle and femoral anteversion after total hip replacement. METHODS: We prospectively examined 52 patients with coxarthrosis, who were treated by total hip replacement. Preoperatively and postoperatively we used a standard X-ray ap view to measure the CCD angle and computerized tomography to determine the femoral anteversion. These projected angles were converted into the real angles by using the method of K?nig and Schult. RESULTS: On average the preoperative real CCD angle was 128 degrees (+/- 8.9 degrees) and the postoperative angle 145 degrees (+/- 4.8 degrees), preoperatively the real femoral anteversion angle was 14.1 degrees (+/- 6.9 degrees) and postoperatively 10.8 degrees (+/- 6.2 degrees). CONCLUSIONS: The effect of the postoperative valgisation can be explained by the given CCD angle of the used femoral stem prosthesis of 140 degrees (cemented Weller II stem) and 145 degrees (cementless CLS classic stem). It is possible that due to the valgisation and the decreased offset of the femoral stem prosthesis compared to the preoperative conditions the gluteal muscles are insufficient and overloaded. It is also known that the change of the femoral anteversion from the physiological conditions causes an increase of the torsional moment. The resulting increased interface load could possibly be a reason for loosening of the femoral stem. The conclusion can be drawn that the CCD angle and the femoral anteversion should more carefully be considered by the surgeon in total hip replacement. This could be reached by an exact implantation technique and the choice of the appropriate stem prosthesis with different CCD angles.     

Correction of lag screw guide pins inappropriately placed during intramedullary hip nailing

INTRODUCTION: Lag screw position is one of the most important controllable factors in trochanteric fracture fixation. However, it is sometimes difficult to handle the lag screw guide pin during intramedullary hip nailing. In this study, causes of guide pin shift and correction of malposition were investigated. METHODS: The movements of guide pins during fracture fixation were traced fluoroscopically using 35 embalmed, mainly anteverted femora, angles were measured in the anteroposterior and lateral planes and necessary corrections calculated. RESULTS: In the proximal anteverted femur, posterior correction of an inappropriately placed guide pin in the lateral plane led to an inferior shift in the anteroposterior fluoroscopic view, and vice versa. Mean anteversion, alpha, beta, and beta' angles were 13.1 degrees (5-29 degrees ), 10.9 degrees (4-18 degrees ), 4.6 degrees (0-10 degrees ) and 4.4 degrees (0-9 degrees ), respectively. The beta' angle was directly proportional to the anteversion angle only, i.e. Y=0.27X+0.65 (R(2)=0.79), p<0.001. CONCLUSIONS: In the proximal anteverted femur, guide pin shift in the anteroposterior fluoroscopic view occurred during correction of pin position in the lateral plane. The amount of shift was directly related to the amount of anteversion.     

股骨干骨折带锁髓内针固定后骨折端旋转畸形的测量

目的　对股骨干骨折带锁髓内针固定后旋转畸形的程度进行定量测定 ,以纠正旋转对位 ,减少其发生率和严重程度。方法　采用CT扫描 (“常用法”)测量 3 6例以闭合复位、带锁髓内针固定治疗的股骨干骨折患者的双侧前倾角 ,计算双侧的差值 ,用来判断骨折远近端旋转畸形的程度。前倾角增大表明远骨折端内旋 ,前倾角减小则代表远骨折端外旋。结果　患侧组前倾角值为 ( 15 0 4±11 3 4 )° ,最大值为 4 8° ,最小值为 - 10° ;健侧组前倾角值为 ( 13 96± 10 2 0 )° ,最大值为 3 1 3 0°,最小值为- 4 8° ,使用配对资料t检验 ,P <0 0 0 1,差异有非常显著性的意义。其中差值最大为 3 7° ,最小为0 90° ,平均相差 10 4 8°。患侧与健侧相比前倾角增大 (远骨折端内旋 )与减小 (远骨折端外旋 )各有 18例 ;而其中内旋者平均为 11 5 6°,外旋者平均为 9 3 9°。内旋小于 10°者有 8例 ,10°至 15°者有 6例 ,大于15°者有 4例 ;外旋小于 10°者有 11例 ,10°至 15°者有 4例 ,大于 15°者有 3例。超过 10°的旋转对位发生率是 4 7% ( 17/ 3 6) ,超过 15°者有 7例 ( 19 4 % )。结论　股骨干骨折采取闭合复位带锁髓内针治疗后旋转畸形的发生率较高 ,临床上应予重视。术中应在影像监视器监控下严格纠正旋转对     

Acetabular anteversion in children.

Acetabular anteversion analysis was performed in 143 normal children, who ranged in age from 1 to 15 years. The mean anteversion value, which remained constant during growth, was 13 degrees.     

Osteotomy for femoral anteversion: A prospective 9-year study of 52 children

Fifty-two children with increased femoral anteversion had bilateral derotational subtrochanteric osteotomies at a mean age of 7 years. They were followed prospectively until at least 15 years of age; the mean observation time was 9 years. They were a subset of 95 children whose 2-year results were reported in 1989. The mean increase of femoral anteversion after the osteotomy was 6° (0.7° per year) and of the neck-shaft angle 5°. The CE angle did not increase. Although we at present practice a more restrictive attitude towards operation of increased femoral anteversion, our study showed that a derotational osteotomy is effective in eliminating the intoeing gait and associated complaints, and the hip angles change only moderately during the remaining period of growth.     

Regression of femoral anteversion. A prospective study of intoeing children

To study the spontaneous regression of femoral anteversion, 30 children referred to the outpatient clinic for intoeing were followed until at least 15 years of age. The mean observation time was 9 (7-12) years, and all the children were examined three times during the growth period. The mean radiographic angle at the first examination was 42 degrees, at the second examination 36 degrees, and at the last examination 28 degrees. The mean decrease of the AV angle per year was 1.5 degrees, with a considerable range (0.2-3.1 degrees). The mean internal rotation of the hip decreased from 74 degrees to 53 degrees during the observation period, and the external rotation increased from 19 degrees to 37 degrees. While all 30 children had an intoeing gait at the first examination, this disappeared in all but 5 children.     

True femoral anteversion during primary total hip arthroplasty: use of postoperative computed tomography-based sections

This study investigated a reference line that is closer to the true femoral anteversion on only the cutting surface of the proximal femoral neck during a femoral stem insertion in a cementless total hip arthroplasty. A postoperative computed tomography of both hips from 33 consecutive patients after a unilateral primary cementless total hip arthroplasty with an avascular necrosis of the femoral head was taken to observe the positioning of the stem and its correlation with the true anteversion of the contralateral side. The average of the midcortical angle was 14.1 degrees +/- 6.8 degrees on the lesion side and 0.1 degrees +/- 1.3 degrees more than the true anteversion on the contralateral side. This study has shown that anteversion using a midcortical line between the anterior cortical line and the posterior cortical line is compatible with the true femoral anteversion. However, further investigation is required to confirm the true femoral anteversion.