Legg-Calvé-Perthes disease: imaging with MR

Magnetic resonance (MR) imaging studies were obtained to evaluate the shape of the cartilaginous femoral head and the adequacy of femoral acetabular containment in 35 children with Legg-Calvé-Perthes disease (LCPD). MR results for 24 of the 35 children were compared with results at arthrography. The shape of the cartilaginous femoral head was well identified with MR imaging, but, with arthrography, less information could be obtained about the medial and lateral aspects of the cartilaginous capital epiphyses in nine and three cases, respectively. Thirteen children underwent surgery; remodeling and regained femoroacetabular congruity of the articular surfaces following derotation varus osteotomy was identified in seven of 10 who underwent repeat MR imaging. In addition, MR images and conventional radiographs of the hips were compared. The radiographically identifiable distribution of the bone necrosis of the capital epiphysis correlated well with that demonstrated on MR images. MR imaging is a valuable non-invasive procedure with which to obtain information about the status and treatment of the cartilaginous femoral head in children with LCPD.     

影像学指标在股髋关节撞击综合征诊断中的价值

目的：本研究前瞻性的分析股髋关节撞击综合征（ Femoroacetabular impingement syn－drome , FAI）的影像学表现,探寻FAI诊断及分型的相关影像学指标,并与手术结果相对照,以期有助于术前对手术方案制定。方法对20例拟诊的FAI患者进行CT检查。观察指标如下：从股骨头异常突起、股骨颈a角、髋臼缘软骨增生硬化。结果20例患者中,共有20个髋关节诊断为FAI,其中左侧9例,右侧11例。股骨颈a角的范围为31．3～69．1,股骨颈a角的平均值为43．55°。股骨头异常突起位于股骨头颈连接处前部或前上部,共11例,占55％,其股骨颈a角的平均值为52．69°;髋臼边缘软骨增生6例,占30％,其股骨颈a角的平均值为39．8°;股骨头颈连接处前部或前上部骨质异常突起与髋臼边缘软骨增生并存3例,占15％,其股骨颈a角的平均值为38．9°。结论 CT诊断指标即股骨头异常突起、a角、髋臼缘软骨增生硬化有助于FAI的诊断、分型及术前病情程度评估,并指导术式选择。     

Proximal focal femoral deficiency.

The term proximal focal femoral deficiency (PFFD) is applied to a spectrum of conditions characterized by partial absence and shortening of the proximal femora and thought to result from an early disturbance of growing mesenchyme. The mildest cases, Classes A and B, exhibit a relatively normal acetabulum and capital femoral epiphysis, despite the dysplastic shaft. There may be a subtrochanteric varus deformity or a pseudoarthrosis accompanying the shortening of the femoral shaft. At the opposite end of the spectrum, the most severely deformed cases, Classes C and D, have involvement of the acetabulum, and the entire proximal femur. In cases of advanced dysgenesis, the findings include: a stunted severely shortened femur with a club-shaped or pointed proximal end, an iliac projection just above the anatomic site of the acetabulum, a spherical obturator foramen, and squaring of the iliac crest. Twenty-one patients (2 bilateral) with proximal focal femoral deficiency are presented (23 femurs). Differentiation of proximal focal femoral deficiency from other congenital and acquired deformities of the hip joint is essential for selecting the proper treatment.     

Proximal femur in biological profile estimation – Current knowledge and future directions

This review presents an overview of the forensic utilities of the proximal femur in the existing literature. The proximal epiphysis of the femur bone is characterized as a skeletal structure that articulates with an acetabulum of a pelvic bone, forming the hip joint and generally accounted for one-fourth of the whole femoral length. Features that are seen in proximal femora include femoral head, fovea capitis, neck, greater and lesser trochanters, and proximal shafts. These can be viable alternatives for assessing the following biological parameters: stature, sex, age, and ancestry. Therefore, if the proximal femur is the only skeletal element that is available for examination, all four of the constituent parts of a biological profile of an unknown individual can be retrieved from analyzing proximal femora using quantitative approaches.     

Bone scintigraphy in slipped capital femoral epiphysis

Tc-99m diphosphonate bone scans were performed on 11 children with slipped capital femoral epiphysis. On pinhole hip images, seven hips in seven patients had increased radionuclide uptake in the physis and adjacent proximal femoral metaphysis where the slip had occurred. Three hips in three patients had decreased radionuclide uptake in the femoral head on the side of the slipped epiphysis, indicating compromise of the femoral head blood supply. Three or more months following internal fixation, three children had scintigraphy that showed loss of the usual focal uptake in the physis and adjacent proximal femoral metaphysis. Bone scintigraphy in pediatric patients with slipped capital femoral epiphysis is valuable in defining the metabolic status of the femoral head. Absence of radiopharmaceutical uptake in the affected femoral head indicates that the femoral head is at risk for development of radiographic changes associated with aseptic necrosis.     

Slipped capital femoral epiphysis. The mechanical function of the periosteum: new aspects and theory including bilaterality.

This particular ailment has many designations in the literature but none is quite adequate. Here we use the terminology slipped capital femoral epiphysis (SCFE). The anatomy of the proximal femur in all mammals reflects their growth and function. The main forces acting on the head are perpendicular to the growth plate. The thick tear-proof perichondrium-periosteum on the femoral neck is like a stocking attached to the epiphysis and the trochanter region. Growth in length causes a strong tensile stress in the periosteum, pressing the epiphysis against the metaphysis and thus stabilizing the vulnerable growth plate-the periosteum theory. Several factors may diminish the stability of the growth plate. SCFE begins with fissures, which coalesce to a fracture in the growth plate, invisible on a radiograph. As the slip progresses, an increasing angulation between the epiphysis and the remainder of the femur occurs. Weight and muscular forces displace the epiphysis posteriorly in a flexed hip. A rift in the ventral half of the periosteal stocking occurs at the border to the perichondrium and, after that, a longitudinal rift in the periosteum at the anterior midline of the femoral neck. This rift becomes broader as the epiphysis slips posteriorly, withdrawing the ruptured periosteum. Displacement of the epiphysis is due to a rotational slip and tilt, made possible by a compression fracture in the posterior part of the metaphysis. Parts of the periosteum function as reins steering the slip direction and counteracting the displacement. SCFE may be regarded as a pseudoarthrosis in the growing cartilage of the plate. The periosteum theory extended to a pseudoarthrosis theory has been supported by findings at surgery and on true lateral radiographs of usual and unusual cases of SCFE presented in this opus. On a true lateral view, the displacement can be measured as the slipping angle (SA) based on anatomical and geometrical considerations. SA values from 95 normal hips and from 22 contralateral asymptomatic hips from SCFE patients are presented in a histogram and bar graph. Statistically, SCFE is always bilateral, but in about 1/3 of the asymptomatic, contralateral hips, the physis ossifies and closes with SA below 13 degrees, and surgery is not necessary. It is most important that the position of the femur on the X-ray table is exactly defined in two dimensions: 1) the angle between the femoral shaft and the tabletop (angle of elevation), 2) the degree of rotation of the femur around its axis. A precisely defined positioning of the femur is a prerequisite for an exact reproducible measurement of the SA on a true lateral view and is also valuable for the evaluation of radiographic "signs". An aid, the Youth Hip Triangle (YHT), has been designed to facilitate positioning of the femur and measurement of SA. YHT is recommended for routine use in every X-ray facility. The method is quick, cost effective and makes it possible to diagnose SCFE in the contralateral hip before clinical signs or symptoms have occurred.     

股骨近段矢状位纵向劈开成形在全髋置换中的应用

目的 总结股骨近段矢状位纵向劈开成形术行全髋置换术治疗髋关节终极疾病合并股骨干骺段狭窄畸形的疗效。 方法 选择2000年1月-2009年12月收治的18例(22髋)髋关节终极疾病合并股骨干骺段狭窄畸形患者,其中男3例,女15例;平均年龄54岁(41～ 75岁)。单髋14例,双髋4例。按Berry分类法,全部患者均被确定为干骺段畸形和大小异常型,其中诊断为发育型(先天性髋关节发育不良)17例,陈旧性髋结核1例。先天性髋关节发育不良者按Crowe等分类法,均被诊断为Ⅳ型。所有患者均采用股骨近段矢状位纵向劈开成形、股骨转子下叠加式缩短截骨和“V”形旋转截骨等手术,并采用标准型股骨柄假体生物学固定。 结果 无感染、脱位、下肢神经牵拉伤,以及股骨近段失控性骨折等并发症。术后X线片示臼杯均位于真臼区,所有股骨柄假体的初始固定质量均优良。所有截骨区在术后3～6个月均获骨性愈合。术后测量显示患肢平均延长3 cm(2.5～3.5 cm)。随访1～10年,平均6年,Harris评分由术前的平均30分改善至术后1年的平均93分。X线片显示无骨溶解,或广泛的X线透亮带、假体进行性下沉、内翻移位等假体松动征。无一例因假体松动或其他原因需行翻修手术者。 结论 髋关节终极疾病合并股骨干骺段狭窄畸形者,采用股骨近段矢状位纵向劈开成形术,并采用标准型股骨柄生物固定假体行全髋置换术治疗可取得满意疗效。     

Normal maturation of the distal femoral epiphyseal cartilage: age-related changes at MR imaging

PURPOSE: To determine how signal intensity in the cartilaginous distal part of the femoral epiphysis varies with (a) age, (b) sex, and (c) distribution to the medial or lateral condyle on magnetic resonance (MR) images. MATERIALS AND METHODS: Sixty-six sagittal T2-weighted or inversion-recovery MR images of the distal femoral epiphysis in children aged 2 months to 5 years 5 months were evaluated. Epiphyses were categorized into five types on the basis of progressive signal intensity changes within the epiphyseal cartilage along the weight-bearing region and posterior condyles. Epiphyseal type was compared with age, sex, and distribution of signal intensity changes within the condyle. RESULTS: In early infancy, epiphyseal cartilage was homogeneous. During the 2nd year, signal intensity along the weight-bearing region decreased. With further advancing age, signal intensity in the posterior femoral condyles increased and became progressively more focal. The increase in epiphyseal grade correlated with age for both the medial and the lateral femoral condyles (r = 0.71 and r = 0.77, respectively; P < .001). There was no significant difference in epiphyseal changes between boys and girls or between medial and lateral condyles. CONCLUSION: There is normal age-related variation in MR imaging signal intensity within the cartilaginous epiphysis of the distal femur. This may be related to weight bearing and epiphyseal maturation and should not be confused with disease.     

Acetabular angles and femoral anteversion in dysplastic hips in adults: CT investigation

Transpelvic CT was used to quantify the relationship between the acetabulum and proximal femur in 21 adult patients (33 hips) with congenital hip dysplasia (defined by a center edge angle of less than 20 degrees). The anterior and posterior acetabular sector angles (AASA and PASA) were measured, as well as the degree of acetabular and femoral anteversion. The results demonstrated deficient anterior acetabular support (i.e., decreased AASA) in approximately two-thirds of the dysplastic hips and reduced posterior support (i.e., decreased PASA) in one-third. The acetabular anteversion was normal. The femoral anteversion. however, was greater than normal in most hip. As important additional information is obtained by CT compared with conventional radiography, CT is recommended when operative procedures aimed at preventing or postponing osteoarthrosis are considered.     

Geometry of proximal femur in the prediction of hip fracture in osteoporotic women

111 White post-menopausal women with hip fracture and 329 healthy controls were studied in order to determine whether proximal femur geometry predicts hip fracture and improves the discriminant ability of femoral neck bone mineral density (BMD) in elderly women. All subjects underwent dual X-ray photon absorptiometry (DXA) of the hip from which the femoral neck BMD, hip axis length, femoral neck width and femoral neck-shaft angle were measured. Fractured subjects had a lower femoral neck BMD, a longer hip axis length and a more valgus neck-shaft angle. The hip axis length correlated significantly with neck-shaft angle, femoral neck width and age. No significant correlation was found between neck-shaft angle and age. On standardized logistic regression, the hip axis length and the neck-shaft angle predicted fracture independently of BMD after correction for age, weight and femoral neck BMD. The femoral neck BMD significantly discriminated fractured subjects after correction for all potential confounders. The logistic models containing simultaneously one femoral geometric parameter and the neck BMD discriminated significantly better than those containing the same variables as single predictor. Our data suggest that hip axis length may play a role in fracture risk and supports a similar role for neck-shaft angle. Combining proximal femur geometric measurements and femoral neck BMD improved the discriminant ability of each measurement.     

High-resolution magnetic resonance imaging of normal porcine cartilaginous epiphyseal maturation

The aim of this study was to determine whether highresolution magnetic resonance (MR) imaging could differentiate epiphyseal and articular cartilage in the cartilaginous epiphysis and demonstrate its developmental changes. T1- and T2-weighted (T1W and T2W) spin-echo sequences at 50-mm field of view (FOV) of hip joints were obtained from 14 piglets (newborn to 6 months). Subsequently, high-resolution MR images (15-mm FOV) of a biopsy core of the proximal femoral cartilaginous epiphysis were correlated with histology. Newborn cartilaginous epiphysis demonstrated homogeneous signal intensity on T1W and T2W imaging with abundant cartilage canals. From 2 weeks of age, the cartilaginous epiphysis showed a diminution of cartilage canals, with three zones evident on T2W imaging consisting of a low-signal middle zone separating two higher signal zones. Histologic evaluation demonstrated four distinct morphologic laminas with a decrease in overall cartilage thickness with age. The laminas were not as well defined in the newborn compared with the older piglets. No simple correlation was found between the MR zonal pattern and the morphological laminas on histology. No distinct demarcation between the articular cartilage and epiphyseal cartilage was present. MR can visualize cartilage canals and demonstrate changes in the cartilaginous epiphysis that occur with maturation. What component of the cartilaginous epiphysis that accounts for the MR differences seen between newborn and older piglets remains unclear.     

Aseptic necrosis following slipped capital femoral epiphysis

Sixty-five patients with slipped capital femoral epiphysis were studied retrospectively for the development of aseptic necrosis. Seven (11%) patients developed segmental or total aseptic necrosis of the capital femoral epiphysis. Radiographically the changes of aseptic necrosis were detectable as early as four months. The cause for the aseptic necrosis is thought to be due to interruption of the blood supply to the capital femoral epiphysis at the time of slippage or during surgical manipulation.     

Slipped capital femoral epiphyses complicating renal osteodystrophy: a report of three cases

Three adolescents with bilateral slipped capital femoral epiphyses complicating renal disease are presented. In one case, the severity of the deformities necessitated total hip replacement. Pathological specimens were available for evaluation. In all 3 cases, epiphysiolysis was accompanied by severe subperiosteal reabsorption along the medial aspect of the femoral neck, widening of the cartilaginous growth plate, and coxa vara. The radiographic diagnosis of a minimally displaced femoral epiphysis may precede the clinical symptoms. Early recognition of this complication is important, since the treatment of choice is prophylactic surgical stabilization before disabling deformities occur.     

Clinical diagnosis of hip pain

This article reviews the evaluation of the hip including the clinical history and physical examination. As our understanding of hip pathology evolves, and arthroscopic and other minimally invasive operative techniques improve, the focus is shifting toward earlier identification of hip pathology. Risk factors for the development of arthritis are now well established and include femoral acetabular impingement, labral tearing, developmental dysplasia, and slipped capital femoral epiphysis. Emerging treatment options may address these conditions in the early stages and prevent or slow the progression of hip degeneration. It is vitally important to elucidate intra-articular versus extra-articular pathology of hip pain in every step of the patient encounter: history, physical examination, and imaging.     

Computed tomography measurements of the acetabulum in adult dysplastic hips: which level is appropriate?

A study has been performed to evaluate whether one or several levels are needed with computed tomography (CT) study to provide sufficient information regarding anteversion and acetabular support to the femoral head. A total of 23 hips in 14 adults with uni- or bilateral congenital hip dysplasia (center-edge angle less than 20°) were assessed by obtaining 5-mm contiguous CT slices and performing acetabular measurements at four levels. Both anterior and posterior acetabular supports as quantified by the anterior and posterior acetabular sector angles were significantly lower than normal at all levels. The sector angles increased in the proximal cuts, whereas the acetabular anteversion increased caudally. Because no important additional information was gained by measuring at different levels, we conclude that CT study at one level is sufficient for acetabular measurements and suggest that the slice through the center of the femoral head is the most appropriate one.     

Forensic age prediction and age classification for critical age thresholds via 3.0T magnetic resonance imaging of the knee in the Chinese Han population

Objectives

To assess the performance of knee MRI for forensic age prediction and classification for 12-, 14-, 16-, and 18-year thresholds.

Methods

The ossification stages of distal femoral epiphyses and proximal tibial epiphyses were assessed using an integrated staging system by Schmeling et al. and Kellinghaus et al. for knee 3.0T MRI with T1-weighted turbo spin-echo (T1-TSE) in sagittal orientation among 852 Chinese Han individuals (483 males and 369 females) aged 7–30 years. Regression models for age prediction were constructed and their performances were evaluated based on mean absolute deviation (MAD) values. In addition, the performances of age classification were assessed using receiver operating characteristic (ROC) analyses.

Results

The intra- and inter-observer agreement levels were very good (κ > 0.80). The complete fusion of those two types of epiphyses took place before 18.0 years in our study participants. The minimum MAD values were 2.51 years (distal femur) and 2.69 years (proximal tibia) in males, and 2.75 years (distal femur) and 2.87 years (proximal tibia) in females. The specificity values of constructed prediction models were all above 90% for the 12-, 14-, and 16-year thresholds, compared to the 74.8–84.6% for the 18-year threshold. Better performances of age prediction and classification were observed in males by distal femoral epiphyses.

Conclusions

Ossification stages via 3.0T MRI of the knee with T1-TSE sequence using an integrated staging system could be a reliable noninvasive method for age prediction or for age classification for 12-, 14-, and 16-year thresholds, especially in males by distal femoral epiphyses. However, assessments based on the full bony fusion of the distal femoral epiphysis and proximal tibial epiphysis seemed not reliable for age classification for the 18-year threshold in the Chinese Han population.

     

MRI features of confirmed "pre-slip" capital femoral epiphysis: a report of two cases

We describe the morphologic and signal changes detected about the proximal femoral growth plate in two patients with hip pain preceding the progression to slipped capital femoral epiphysis using magnetic resonance imaging.     

Strong correlation between the morphology of the proximal femur and the geometry of the distal femoral trochlea

Purpose

Previous investigations suggested that the geometry of the proximal femur may be related to osteoarthritis of the tibiofemoral joint and various patellofemoral joint conditions. This study aims to investigate the correlation between proximal and distal femoral geometry. Such a correlation could aid our understanding of patient complications after total knee arthroplasty (TKA) and be of benefit for further development of kinematic approaches in TKA.

Methods

CT scans of 60 subjects (30 males, 30 females) were used to identify anatomical landmarks to calculate anatomical parameters of the femur, including the femoral neck anteversion angle, neck–shaft angle (NSA), mediolateral offset (ML-offset), condylar twist angle (CTA), trochlear sulcus angle (TSA) and medial/lateral trochlear inclination angles (MTIA/LTIA). Correlation analyses were carried out to assess the relationship between these parameters, and the effect of gender was investigated.

Results

The CTA, TSA and LTIA showed no correlation with any proximal parameter. The MTIA was correlated with all three proximal parameters, mostly with the NSA and ML-offset. Per 5° increase in NSA, the MTIA was 2.1° lower (p < 0.01), and for every 5 mm increase in ML-offset, there was a 2.6° increase in MTIA (p < 0.01). These results were strongest and statistically significant in females and not in males and were independent of length and weight.

Conclusions

Proximal femoral geometry is distinctively linked with trochlear morphology. In order to improve knowledge on the physiological kinematics of the knee joint and to improve the concept of kinematic knee replacement, the proximal femur seems to be a factor of clinical importance.

Level of evidence

III.     

Skeletal development in fetal pig specimens: MR imaging of femur with histologic comparison

PURPOSE: To evaluate the magnetic resonance (MR) imaging features of the developing femur in fetal pig specimens. MATERIALS AND METHODS: MR images of 15 fetal pig femurs, which were categorized into three groups of specimens representing each third of the gestational period, were used to compare increasing femoral length (as an indication of gestational age) with epiphyseal growth in multiple dimensions by using Pearson product moment correlation. Physeal-epiphyseal demarcation, visibility of the secondary ossification center and its physis, prominence of the perichondrial structures (ie, groove of Ranvier and bone bark), metaphyseal undulation, and corticomedullary differences were evaluated qualitatively. These features were also evaluated on histologic sections. RESULTS: With femoral length measurements used as indications of gestational age, there were three, five, and seven fetal pig specimens in each gestation group. During fetal development, the cartilaginous epiphysis of the distal femur transformed from an oval to a bicondylar structure, with most of the growth occurring sagittally (P < .001). Physeal-epiphyseal demarcation, visibility of the secondary ossification center and its physis, and metaphyseal undulation increased later in gestation. Detection of perichondrial structures, however, was greatest during the middle third of gestation and decreased thereafter. During the fetal period, the perichondrial groove of Ranvier and the bone bark were easily identifiable at MR imaging. Marrow cavitation increased with gestation. CONCLUSION: MR imaging depicts fetal pig skeletal features that can be confirmed histologically and that may prove to be useful at human prenatal skeletal imaging.     

Acute epiphyseal osteomyelitis in children

Nine children over 20 months of age had acute osteomyelitis of the epiphysis of a long bone. The clinical features varied, but all of the patients had pain at the infected site and an elevated erythrocyte sedimentation rate. The distal femur was involved in seven cases, the proximal tibia in two, and the proximal humerus in one. In two patients there was a contiguous metaphyseal lesion, while the other seven patients (eight sites) had lesions limited to the epiphysis. Bone scintigraphy clearly identified the infected sites in all seven patients in whom it was performed, and allowed an early diagnosis in four cases. Radiographs showed a lytic lesion of the epiphysis that corresponded to the scintigraphic findings in all cases. The vascular supply to the epiphysis and the microscopic structure of the epiphyseal venous sinusoids provide locations that favor lodgement of blood-borne organisms. The epiphysis of the child should be recognized as another site of hematogenous osteomyelitis.