Objective: To determine whether femoral osteotomies that change frontal plane alignment without affecting torsion influence anteversion and inclination. Methods: Femurs without deformity were scanned to create three-dimensional reconstructions. The femoral head-neck axis was identified by placement of a virtual intramedullary pin. Femoral anteversion was measured from an axial image in all three conditions. Femoral inclination was calculated for all conditions using the neck-shaft and anteversion angles. Changes in anteversion and inclination were calculated and compared using a one-way repeated measures analysis of variance.
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Reorientation acetabular osteotomies can correct dysplastic deformities and provide marked improvement in hip function. Deformities of the proximal femur can produce suboptimal articulation or secondary impingement after acetabular reorientation, yet the incidence and characteristics of such deformities have not been well described. To describe the proximal femoral anatomy in patients with symptomatic acetabular dysplasia, we retrospectively analyzed the radiographs of hips treated with periacetabular osteotomy.
The radiographic findings were compared with those in 22 control hips. In the dysplastic group, 80 hips were in women and 28 in men, and the average age was When compared with the control hips, dysplastic hips had differences in parameters of proximal femoral anatomy that we measured.
These data demonstrate a high incidence of proximal femoral abnormalities associated with acetabular dysplasia. Identifying and treating these abnormalities may optimize joint congruency and minimize secondary impingement after acetabular reorientation. Level of Evidence: Level II, diagnostic study.
See the Guidelines for Authors for a complete description of levels of evidence. Periacetabular osteotomy [ 7 ] is an effective treatment for symptomatic acetabular dysplasia [ 2 , 3 , 7 , 9 , 10 , 18 , 22 ], and ongoing efforts are directed at optimizing the efficacy of this procedure. The clinical results of acetabular reorientation are dependent on various patient-specific factors as well as the precision of the surgical correction.
The technical goals of surgery are to correct structural instability, optimize joint biomechanics, normalize articular loading, and avoid secondary femoroacetabular impingement. Although attention has focused on obtaining optimal acetabular reduction, less emphasis has been placed on the structural characteristics of the proximal femur that may contribute to femoroacetabular impingement after acetabular reorientation.
Femoral deformities associated with acetabular dysplasia have been well documented in the literature [ 12 , 14 , 16 , 19 , 20 ]. The most common deformities include femoral anteversion, an aspheric femoral head, and reduced femoral head-neck offset. Nevertheless, there is limited comprehensive information regarding these deformities relative to acetabular reorientation surgery.
The primary purpose of this study was to determine the incidence and characteristics of proximal femoral abnormalities in symptomatic dysplastic hips.
Secondarily, we compared the proximal femoral anatomy of dysplastic hips with that in a cohort of control hips. We compared the findings with a series of radiographs from a group of asymptomatic patients control group we previously reported [ 4 , 15 ]. Fourteen patients had staged bilateral periacetabular osteotomies 10 women, four men.
The average age of all study patients was Twelve patients 13 hips had at least one osteotomy procedure before presentation. This study was performed under an Institutional Review Board-approved protocol.
The control group consisted of a series of patients that we had previously reported [ 4 , 15 ]. None of the patients had groin pain, irritability of the hip, or a positive impingement test. All of these patients had signs and symptoms completely consistent with a diagnosis not involving the hip ie, lumbar osteoarthritis or lumbar radiculopathy. All radiographic measurements were performed by one observer RMN. All patients had a complete set of preoperative radiographs, which included an anteroposterior AP pelvis, AP hip, false profile [ 8 ], crosstable lateral, and frog-leg lateral of the affected hip s.
Radiographs were performed using standardized techniques as previously reviewed [ 4 ]. Commonly reported radiographic parameters of hip structure were used to objectively define the acetabular and femoral anatomy [ 4 , 15 ]. On the AP pelvis radiograph, the lateral center-edge angle [ 23 ], acetabular inclination [ 21 ], femoral head-neck shaft angle, and congruency [ 24 ] of the hip were assessed. The femoral neck-shaft angle was measured on the AP radiograph of the hip [ 15 , 17 ].
The femoral head-neck offset distance and femoral head diameter were measured on the crosstable lateral and frog-leg lateral images using the method described by Eijer et al. The femoral head-neck offset ratio, defined as the ratio between the head-neck offset distance and the femoral head diameter, was calculated to standardize the head-neck offset for comparison between patients [ 6 ].
Femoral head sphericity was determined using circular templates to determine if the head and head-neck junction were contained within the circle [ 4 ].
Frog-leg lateral radiographs show A assessment of femoral head sphericity using a spheric template arrow , B measurement of head-neck offset HNO, arrow as described by Eijer et al.
The frog-leg lateral radiograph accurately visualized hip cam impingement abnormalities. Clin Orthop Relat Res. Proximal femoral deformities were present in All hips with coxa vara had a previous proximal femoral varus-producing osteotomy. Proximal femoral deformities associated with acetabular dysplasia. A An anteroposterior radiograph of the left hip in a year-old woman with a history of insidious-onset hip pain demonstrates acetabular dysplasia and associated coxa valga.
B Anteroposterior right hip radiograph of a year-old female patient with a history of developmental hip dysplasia and previous proximal femoral varus-producing osteotomy shows residual coxa vara. Reduced femoral head-neck offset associated with acetabular dysplasia. Anteroposterior and frog-leg lateral radiographs of a year-old woman with hip pain.
A The anteroposterior view demonstrates acetabular dysplasia with a spheric femoral head. B The frog-leg lateral view depicts an area of insufficient head-neck offset anteriorly arrow. Asphericity of the femoral head associated with acetabular dysplasia. Anteroposterior and frog-leg lateral radiographs of the right hip in a year-old man with hip pain. A The anteroposterior view demonstrates acetabular dysplasia and mild asphericity of the femoral head.
B The frog-leg lateral radiograph better visualizes the aspheric head shape and insufficient offset of the head-neck junction. Anterior femoroacetabular impingement is a known cause of recurrent symptoms after acetabular reorientation for the treatment of symptomatic hip dysplasia [ 11 ]. Therefore, the purpose of this study was to define the incidence and characteristics of proximal femoral abnormalities in the setting of symptomatic dysplasia and to compare these findings with a cohort of control hips.
The limitations of this study primarily include its descriptive design and lack of clinical outcome data regarding combined femoral and acetabular reorientation procedures. Nevertheless, our stated purpose was to characterize these femoral deformities as a first step in determining the potential need for femoral-sided augmentation procedures. The second major weakness is the control cohort was established retrospectively. These patients were determined by the senior author to not have symptoms relative to the hip.
Nevertheless, the possibility of an atypical clinical presentation of hip disease cannot be entirely excluded for these patients. If present, this would be uncommon and unlikely to affect the conclusion regarding comparison of the dysplasia and control cohorts.
The final major weakness is our analysis and conclusions are based on plain radiographs only, and three-dimensional imaging was not used. This radiographic evaluation has limitations in detecting certain deformities like proximal femoral anteversion. Our analysis of proximal femoral anatomy in the dysplastic hip and comparison with control hips produced several major findings.
Coxa vara was present as a result of previous proximal femoral varus osteotomy in all cases. Our results are consistent with other data in the literature. Specifically, Okano et al. Additional studies [ 12 , 20 ] with three-dimensional analyses have also highlighted the common deformity of increased proximal femoral anteversion. Collectively, these data indicate proximal femoral abnormalities are quite common in hips that are symptomatic from structural instability. Many of these deformities predispose the hip to continued structural instability coxa valga or secondary femoroacetabular impingement head-neck offset abnormalities after acetabular reorientation.
These findings should prompt surgeons to analyze the proximal femoral anatomy preoperatively and to contemplate whether the deformity should be corrected at the time of the acetabular procedure.
The major technical goals of acetabular reorientation are to create stable articulation, improve articular loading patterns, and to prevent secondary femoroacetabular impingement.
The periacetabular osteotomy is advantageous because it allows major multiplanar corrections [ 2 ]. Nevertheless, this advantage is tempered by the potential problem of overcorrection or improper reduction. Even with an appropriate correction, the periacetabular osteotomy reduces hip flexion motion [ 18 , 22 ]. Therefore, enhancing impingement-free flexion motion is a major goal of the procedure. In hips with an aspheric femoral head or reduced anterolateral femoral head-neck offset, secondary femoroacetabular impingement can be problematic after acetabular repositioning [ 11 ] because the more normal position of the acetabular rim creates abnormal contact with the deformity of the proximal femur insufficient head-neck offset.
In this setting, the surgeon may consider a head-neck osteochondroplasty to prevent femoroacetabular impingement. In our practice, it is now routine to perform anterior arthrotomy to assess the labrum and, more importantly, inspect the relationship of the acetabular rim and the femoral head-neck junction. The contour of the head-neck junction is directly visualized and is tested in hip flexion and internal rotation.
In cases of acetabular dysplasia with associated coxa valga, we recommend performing the acetabular reorientation followed by careful assessment of joint stability directly through the anterior arthrotomy and by intraoperative radiographic evaluation.
If residual instability is present subluxation, incongruency, or insufficient head coverage , proximal femoral varus osteotomy can be considered. Perthes-like deformities pose the most difficult problems because the acetabular dysplasia can be associated with major deformities of the proximal femur.
Isolated acetabular reorientation in this setting can be problematic as a result of secondary femoroacetabular impingement. These data demonstrate proximal femoral abnormalities are commonly associated with symptomatic acetabular dysplasia. These abnormalities can result from the primary hip deformity or may be secondary to previous surgical treatment.
To optimize surgical reconstruction of the hip, it is important to emphasize the proximal femoral anatomy should be evaluated preoperatively.
This facilitates preoperative planning and provides information regarding comprehensive surgical reconstruction of the joint. The surgeon must also balance the potential benefit of a femoral procedure with the associated risks and complications. Specifically, a proximal femoral osteotomy considerably increases the magnitude of the procedure and prolongs the postoperative rehabilitation.
Alternatively, osteochondroplasty of the femoral head-neck junction at the time of arthrotomy seems to be well tolerated and not associated with major risks. In our practice, we commonly combine a proximal femoral procedure with acetabular reorientation to enhance hip stability, congruency, and impingement-free flexion motion of the hip.
Mid- and long-term data analyzing the clinical results of these techniques is important in defining the role of proximal femoral procedures in combination with periacetabular osteotomy. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center for Research Resources or the National Institutes of Health.
Each author certifies that his or her institution has approved the reporting of these cases, that all investigations were conducted in conformity with ethical principles of research, and that informed consent for participation in the study was obtained. National Center for Biotechnology Information , U. Published online Nov John C. Clohisy , MD, 1 Ryan M. Nunley , MD, 1 Jack C.
What are coxa valga and coxa vara?
Coxa valga is a deformity of the hip where the angle formed between the head and neck of the femur and its shaft is increased, usually above degrees. The differential diagnosis includes neuromuscular disorders i. From Wikipedia, the free encyclopedia. This article does not cite any sources. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.
The Effect of Valgus and Varus Femoral Osteotomies on Measures of Anteversion in the Dog
Reorientation acetabular osteotomies can correct dysplastic deformities and provide marked improvement in hip function. Deformities of the proximal femur can produce suboptimal articulation or secondary impingement after acetabular reorientation, yet the incidence and characteristics of such deformities have not been well described. To describe the proximal femoral anatomy in patients with symptomatic acetabular dysplasia, we retrospectively analyzed the radiographs of hips treated with periacetabular osteotomy. The radiographic findings were compared with those in 22 control hips. In the dysplastic group, 80 hips were in women and 28 in men, and the average age was When compared with the control hips, dysplastic hips had differences in parameters of proximal femoral anatomy that we measured.