A Cam Morphology Develops in the Early Phase of the Final Growth Spurt in Adolescent Ice Hockey Players: Results of a Prospective MRI-based Study

BACKGROUND

Cam morphologies seem to develop with an increased prevalence in adolescent boys performing high-impact sports. The crucial question is at what age the cam morphology actually develops and whether there is an association with an aberration of the shape of the growth plate at the cam morphology site.

QUESTIONS/PURPOSES

(1) What is the frequency of cam morphologies in adolescent ice hockey players, and when do they appear? (2) Is there an association between an extension of the physeal growth plate and the development of a cam morphology? (3) How often do these players demonstrate clinical findings like pain and lack of internal rotation?

METHODS

A prospective, longitudinal MRI study was done to monitor the proximal femoral development and to define the appearance of cam morphologies in adolescent ice hockey players during the final growth spurt. Young ice hockey players from the local boys' league up to the age of 13 years (mean age 12 ± 0.5 years) were invited to participate. From 35 players performing on the highest national level, 25 boys and their parents consented to participate. None of these 25 players had to be excluded for known disease or previous surgery or hip trauma. At baseline examination as well as 1.5 and 3 years later, we performed a prospective noncontrast MRI scan and a clinical examination. The three-dimensional morphology of the proximal femur was assessed by one of the authors using radial images of the hip in a clockwise manner. The two validated parameters were: (1) the alpha angle for head asphericity (abnormal > 60°) and (2) the epiphyseal extension for detecting an abnormality in the shape of the capital physis and a potential correlation at the site of the cam morphology. The clinical examination was performed by one of the authors evaluating (1) internal rotation in 90° of hip and knee flexion and (2) hip pain during the anterior impingement test.

RESULTS

Cam morphologies were most apparent at the 1.5-year follow-up interval (10 of 25; baseline versus 1.5-year follow-up: p = 0.007) and a few more occurred between 1.5 and 3 years (12 of 23; 1.5-year versus 3-year follow-up: p = 0.14). At 3-year follow-up, there was a positive correlation between increased epiphyseal extension and a high alpha angle at the anterosuperior quadrant (1 o'clock to 3 o'clock) (Spearman correlation coefficient = 0.341; p < 0.003). The prevalence of pain on the impingement test and/or restricted internal rotation less than 20° increased most between 1.5-year (1 of 25) and the 3-year follow-up (6 of 22; 1.5-year versus 3-year follow-up: p = 0.02).

CONCLUSION

Our data suggest that a cam morphology develops early during the final growth spurt of the femoral head in adolescent ice hockey players predominantly between 13 to 16 years of age. A correlation between an increased extension of the growth plate and an increased alpha angle at the site of the cam morphology suggests a potential underlying growth disturbance. This should be further followed by high-resolution or biochemical MRI methods. Considering the high number of cam morphologies that correlated with abnormal clinical findings, we propose that adolescents performing high-impact sports should be screened for signs of cam impingement, such as by asking about hip pain and/or examining the patient for limited internal hip rotation.

LEVEL OF EVIDENCE

Level I, prognostic study.

Hip Structural Analysis Reveals Impaired Hip Geometry in Girls With Type 1 Diabetes

CONTEXT

Among patients with type 1 diabetes (T1D), the risk of hip fracture is up to 6-fold greater than that of the general population. However, the cause of this skeletal fragility remains poorly understood.

OBJECTIVE

To assess differences in hip geometry and imaging-based estimates of bone strength between youth with and without T1D using dual-energy x-ray absorptiometry (DXA)-based hip structural analysis.

DESIGN

Cross-sectional comparison.

PARTICIPANTS

Girls ages 10 to 16 years, including n = 62 with T1D and n = 61 controls.

RESULTS

The groups had similar age, bone age, pubertal stage, height, lean mass, and physical activity. Bone mineral density at the femoral neck and total hip did not differ in univariate comparisons but was lower at the femoral neck in T1D after adjusting for bone age, height, and lean mass. Subjects with T1D had significantly lower cross-sectional area, cross-sectional moment of inertia, section modulus, and cortical thickness at the narrow neck, with deficits of 5.7% to 10.3%. Cross-sectional area was also lower at the intertrochanteric region in girls with T1D. Among those T1D subjects with HbA1c greater than the cohort median of 8.5%, deficits in hip geometry and strength estimates were more pronounced.

CONCLUSIONS

DXA-based hip structural analysis revealed that girls with T1D have unfavorable geometry and lower estimates of bone strength at the hip, which may contribute to skeletal fragility and excess hip fracture risk in adulthood. Higher average glycemia may exacerbate effects of T1D on hip geometry.

Physical Activity Throughout Adolescence and Peak Hip Strength in Young Adults

IMPORTANCE

Peak bone strength, which occurs in early adulthood, is an important marker of the future risk of osteoporosis. It is therefore important to identify modifiable early life factors that are associated with the attainment of peak hip strength.

OBJECTIVE

To investigate the association of time spent in moderate to vigorous-intensity and light-intensity physical activity throughout adolescence with peak hip strength in adulthood.

DESIGN, SETTING, AND PARTICIPANTS

The Avon Longitudinal Study of Parents and Children is a prospective birth cohort study that initially recruited all pregnant women residing within the catchment area of 3 health authorities in southwest England who had an expected delivery date between April 1, 1991, and December 31, 1992. In total, 15 454 eligible pregnant women were enrolled, and 15 589 infants were delivered. Of those, 14 901 infants were alive at age 1 year. The present analysis examined 2569 healthy offspring who had valid physical activity measurements obtained during a clinical assessment for at least 1 age (12, 14, 16, and/or 25 years), with up to 4 repeated accelerometer assessments performed (1 per age-associated clinical visit). Data were analyzed from June 2019 to June 2020.

EXPOSURES

Trajectories of accelerometer-assessed time spent in moderate to vigorous-intensity and light-intensity physical activity at ages 12, 14, 16, and 25 years (measured in minutes per day) were identified using latent trajectory modeling. Moderate to vigorous-intensity and light-intensity physical activity were determined using established thresholds of acceleration counts per minute.

MAIN OUTCOMES AND MEASURES

Femur neck bone mineral density (BMD; measured in g/cm2) at age 25 years assessed by dual-energy radiography absorptiometry scans of the hip.

RESULTS

A total of 2569 participants (1588 female participants [62%]) were included in the analysis. Male participants spent more time in moderate to vigorous-intensity activity at each age and had greater adult femur neck BMD than female participants. For each sex, 3 moderate to vigorous-intensity trajectory subgroups and 3 light-intensity trajectory subgroups were identified. With regard to the moderate to vigorous-intensity trajectories, most male participants (85%) were in the low adolescent subgroup, with only 6% and 9% in the high early-adolescent and high mid-adolescent subgroups, respectively. Moderate to vigorous-intensity trajectories in female participants were divided into low adolescent-low adult (73%), low adolescent-high adult (8%), and high adolescent (19%) subgroups. Light-intensity physical activity trajectories were classified into low nonlinear, moderate decreasing, and high decreasing subgroups for both sexes. Femur neck BMD in male participants was greater in the high early-adolescent subgroup (0.38 g/cm2; 95% CI, 0.11-0.66 g/cm2) and the high mid-adolescent subgroup (0.33 g/cm2; 95% CI, 0.07-0.60 g/cm2) compared with the low adolescent (reference) subgroup. Femur neck BMD in female participants was greater in the high adolescent subgroup (0.28 g/cm2; 95% CI, 0.15-0.41 g/cm2) but not in the low adolescent-high adult subgroup (-0.12 g/cm2; 95% CI, -0.44 to 0.20 g/cm2) compared with the low adolescent-low adult (reference) subgroup. A sensitivity analysis using a negative-outcome control variable to explore unmeasured confounding supported these findings. The light-intensity trajectories were not associated with femur neck BMD; for example, differences in femur neck BMD between the high decreasing and low nonlinear subgroups were 0.16 g/cm2 (95% CI, -0.08 to 0.40 g/cm2) in male participants and 0.20 g/cm2 (95% CI, -0.05 to 0.44 g/cm2) in female participants.

CONCLUSIONS AND RELEVANCE

Supporting high-intensity physical activity throughout early life may help to maximize peak hip strength and prevent osteoporosis in later life. Replication of our findings in independent studies will be important.

Abnormal expression of Pappa2 gene may indirectly affect mouse hip development through the IGF signaling pathway

INTRODUCTION

Developmental dysplasia of the hip (DDH) is a major cause of disability in children, and the genetic mechanism of this disease remains unclear. In our previous study, we found that pregnancy-associated plasma protein-A2 (PAPP-A2) was associated with DDH significantly.

OBJECTIVES

The aim of this study was to investigate the insulin-like growth factor (IGF) expression and collagen synthesis as well as cartilage proliferation-related proteins in the case of abnormal expression of Pappa2 in mice to research the relationship between PAPP-A2 and the pathological changes of DDH.

METHODS

In vivo animal experiments, the mice were directly injected with 50 µl of Cas9/PAPP-A2 sgRNA lentiviruses around the hip to downregulate the Pappa2 gene expression and injected with control lentiviruses on the other side, then to observe the expression and localization of related proteins. And in an in vitro experiment, mice fibroblasts and primary chondrocytes were cultured with insulin-like growth factor binding protein-5 (IGFBP-5) protein, PAPP-A2 protein and Cas9/PAPP-A2 sgRNA lentiviruses to detect of related proteins and mRNA expression.

RESULTS

Cartilage proliferation-related proteins demonstrated a significant decrease in the PAPP-A2 knockdown hips acetabulum and femoral head cartilage, meanwhile the IGF expression was also downregulated in the soft tissue around the acetabulum compared with the control hips. Furthermore, the role PAPP-A2 played in chondrocytes and fibroblasts was the same as in the in vivo experiments, downregulation of PAPP-A2 expression or upregulation of IGFBP-5 expression can reduce collagen synthesis and cartilage proliferation.

CONCLUSIONS

PAPP-A2 may be involved in the development of the mouse hip joint by interfering the fibrous and cartilaginous metabolism via IGF pathway-associated proteins pathway.

Magnetic resonance imaging evaluation of the labrum to predict acetabular development in developmental dysplasia of the hip: A STROBE compliant study

Recently, more attention has been paid to the role of the acetabular labrum. Therefore, we designed a retrospective cohort study of patients with residual hip dysplasia (RHD) who underwent magnetic resonance imaging (MRI). The objective of this study was to investigate an association between the MRI appearance of the labrum before school age and the natural history of RHD.We retrospectively investigated 45 hips of 40 patients who underwent MRI at about 3 and 4 years of age for RHD and were conservatively followed up with until 6 years of age or older. We evaluated the extent of eversion with a new method that measures the β angle (MRI β angle) using landmarks of the Graf method on MRI T2*-weighted images. The outcome measure was the Severin classification at the final follow-up. We compared the radiographic and MRI parameters at approximately 3 and 4 years of age between the good and poor outcome groups. The Student t test or one-way analysis of variance was used to compare the quantitative variables between groups. The Chi-square test was used to perform a ratio comparison.Although there was a significant difference in the center-edge (CE) angle, there was no significant difference in the acetabular index and the ratio of the presence of femoral head necrosis and the break in Shenton line between the good and poor groups. The MRI β angle was significantly greater in the poor outcome group than in the normal and good outcome groups. The cut-off value of the MRI β angle to differentiate the good and poor outcome groups was 65°, and its specificity and sensitivity were 92% and 53%, respectively.There was labral eversion on MRI scans in patients with RHD. Acetabular development before adolescence was poorer with greater labral eversion on MRI scans. The specificity for poor acetabular development was high when the MRI β angle was 65° or more. The MRI β angle has the potential to predict acetabular development.

The effect of prepubertal calcium carbonate supplementation on skeletal development in Gambian boys-a 12-year follow-up study

CONTEXT

Calcium intake during growth is essential for future bone health but varies widely between individuals and populations. The impact on bone of increasing calcium intake is unknown in a population where low calcium intake, stunting, and delayed puberty are common.

OBJECTIVE

To determine the effect of prepubertal calcium supplementation on mean age at peak velocity for bone growth and mineral accrual.

DESIGN AND SETTING

Prospective follow-up of boys in rural Gambia, West Africa, who had participated in a double-blind, randomized, placebo-controlled trial of calcium supplementation.

PARTICIPANTS

Eighty boys, initially aged 8.0-11.9 years, were followed up for 12 years.

INTERVENTIONS

Subjects received 1 year of calcium carbonate supplementation (1000 mg daily, 5 d/wk).

MAIN OUTCOME MEASURES

Dual-energy x-ray absorptiometry measurements were carried out for whole body (WB), lumbar spine, and total hip bone mineral content, bone area (BA), and WB lean mass. Super imposition by translation and rotation models was made to assess bone growth.

RESULTS

Age at peak velocity was consistently earlier in the calcium group compared to the placebo group, for WB bone mineral content (mean, -6.2 [SE, 3.1]; P = .05), WB BA (mean, -7.0 [SE, 3.2] mo; P = .03), lumbar spine and total hip BA. By young adulthood, supplementation did not change the amount of bone accrued (mineral or size) or the rate of bone growth.

CONCLUSIONS

Twelve months of prepubertal calcium carbonate supplementation in boys with a low calcium diet advanced the adolescent growth spurt but had no lasting effect on bone mineral or bone size. There is a need for caution when applying international recommendations to different populations.

Fundamental concepts of developmental dysplasia of the hip

To provide the best possible care to patients with developmental dysplasia of the hip, it is helpful to understand the normal growth and development of the hip joint; the pathoanatomy, epidemiology, and diagnosis of the condition; and the natural history of a missed diagnosis of dislocation, subluxation, and dysplasia.

Developmental dysplasia of the hip: diagnosis and management to 18 months

Developmental dysplasia of the hip represents a spectrum of disease ranging from transient neonatal instability to established dislocation. It is accepted that female sex, breech presentation, and family history are risk factors for the disease. Early diagnosis by clinical examination or ultrasound imaging is emphasized, with splint treatment ideally commencing by 6 weeks of age. Treatment using the Pavlik harness is successful in up to 90% of patients. Ultrasound imaging is the gold standard for monitoring a patient during harness wear. Failed splintage or late presentation usually necessitates surgical intervention depending on the patient's age and the severity of the hip dysplasia and displacement.

Surgical treatment of developmental dysplasia of the hip

Ideally, developmental dysplasia of the hip is treated early in childhood by nonsurgical methods. If these methods are ineffective, surgical reduction in a nonambulating child is required. A young child (age 6 to 18 months) who requires surgical reduction can be treated by formal anterior open reduction or by the medial Ludloff approach to the hip. Additional bony procedures are usually not required in these young patients. Delayed diagnosis is still common, requiring surgical reduction for children of walking age. These older children usually require formal open reduction (anterior approach) plus an associated bony osteotomy (acetabular, proximal femoral, or, in some cases, both types of osteotomies) to better stabilize the hip. The addition of a proximal femoral derotational shortening osteotomy for open reduction in older children was first used in children older than 3 years, but now it is commonly used in children as young as 2 years. This osteotomy decreases the forces on the reduced hip and minimizes the chances for redislocation and osteonecrosis. In all surgical procedures for developmental dysplasia of the hip, the surgeon must avoid too great a focus on bony osteotomies because the management of soft-tissue abnormalities is critical in achieving a stable reduction.

Diagnosis and management of developmental dysplasia of the hip from triradiate closure through young adulthood

The current treatment of painful hip dysplasia in the mature skeleton is based on acetabular reorientation. Reorientation procedures attempt to optimize the anatomic position of the hyaline cartilage of the femoral head and acetabulum in regard to mechanical loading. Because the Bernese periacetabular osteotomy is a versatile technique for acetabular reorientation, it is helpful to understand the approach and be familiar with the criteria for an optimal surgical correction. The femoral side bears stigmata of hip dysplasia that may require surgical correction. Improvement of the head-neck offset to avoid femoroacetabular impingement has become routine in many hips treated with periacetabular osteotomy. In addition, intertrochanteric osteotomies can help improve joint congruency and normalize the femoral neck orientation. Other new surgical techniques allow trimming or reducing a severely deformed head, performing a relative neck lengthening, and trimming or distalizing the greater trochanter.  An increasing number of studies have reported good long-term results after acetabular reorientation procedures, with expected joint preservation rates ranging from 80% to 90% at the 10-year follow-up and 60% to 70% at the 20-year follow-up. An ideal candidate is younger than 30 years, with no preoperative signs of osteoarthritis. Predicted joint preservation in these patients is approximately 90% at the 20-year follow-up. Recent evidence indicates that additional correction of an aspheric head may further improve results.

Does dynamic immobilization reduce chondrocyte apoptosis and disturbance to the femoral head perfusion?

The purpose of this study is to investigate whether the dynamic hip immobilization is more favourable for lessening ischemic injury to the immature femoral head than a static immobilization. 152 Japanese white rabbits were divided into four groups randomly, and the hips were immobilized into "human" position (group A), "frog leg" position (group B) and "dynamic frog leg" position (group C). Group D was used as control. Ten rabbits in each group were killed, and the hip specimens were harvested at 1, 2, and 3 weeks after immobilization. Bcl-2/Bax expression balance and chondrocytes apoptosis were analyzed. The remaining eight rabbits in each group were used to measure the blood supply of capital femoral epiphysis by selective vascular perfusion with Indian ink. The Bcl-2/Bax expression ratio in group C was significantly increased than that in group A and B (p<0.001), while that was not significantly different from control group (p=0.0592). At three weeks after immobilization, the average apoptotic ratio was 36.7%, 45.8%, and 26.7% in group A, B and C, respectively (p<0.01). There was no significant difference between group C and normal control (p=0.0597). The perfusion ratio was 0.03±0.03, 0.03±0.02, and 0.08±0.03 in group A, B and C respectively, and 0.12±0.04 in control group (p<0.05). Thus, the dynamic immobilization model exhibited a relatively less chondrocytes apoptosis and disturbance to the femoral head perfusion than other immobilizations in vivo, which therefore may be useful for reducing avascular necrosis following the treatment of developmental dysplasia of the hip.

Hip joint development in children with type IIb developmental dysplasia

PURPOSE

The aim of this study was to analyse the results of treatment of sonographically diagnosed type IIb developmental hip dysplasia and to identify residual hip dysplasia using clinical and radiological assessment.

METHODS

We retrospectively reviewed the data of 49 children (59 type IIb and 39 type I hips, according to Graf's monographic classification) treated in abduction braces. The mean age was 9.1 years (range 4-15) at latest follow-up.

RESULTS

According to the clinical classification of Mckay in Barrett's modification, all the type I and type IIb hips had very good results. No statistical differences were found between type I and IIb hips when comparing both measured radiological parameters and radiological results according to the Severin classification at latest follow-up. Using our criteria (two or more radiological parameters were outside of their normal range), 12 out of 49 type IIb hips demonstrated persistent dysplasia. Of the 12 hips, eight sonograms were normal at the end of treatment and four patients failed to normalise. No type I hips demonstrated two or more abnormal radiographic parameters at latest follow-up.

CONCLUSIONS

Despite obtaining normal sonograms at the end of treatment, some children with type IIb dysplasia may demonstrate radiographic evidence of persistent hip dysplasia over a longer follow-up period. Our results suggest that these children should be monitored until skeletal maturity.

Femoral neck bone strength estimated by hip structural analysis (HSA) in Swedish Caucasians aged 6-90 years

Dual-energy X-ray absorptiometry hip scans of 1,760 population-based Caucasians, 599 girls and 642 boys aged 6-19 years and 270 women and 249 men aged 20-90 years, were analyzed with the hip structural analysis (HSA) software to present age- and sex-specific normative HSA data of the femoral neck (FN). Measured traits included bone mineral density (BMD), cross-sectional area (CSA), section modulus (Z), periosteal diameter (PD), endosteal diameter (ED), cortical thickness (CT), and cross-sectional moment of inertia (CSMI). When plotting the measured traits versus age, the curves increased with higher ages until statistically significant break points were reached, for all traits at age 17 in girls and age 19 in boys. After the break points, PD and ED increased with higher ages but, as ED increased more than PD, BMD and CT decreased significantly with higher ages. The decline in BMD was counteracted by the increase in bone size so that there was only a nonstatistically significant decrease in bone strength, estimated as Z and CSMI, from break point to age 90. The partial preservation of bone strength was more obvious in men than in women as the decline in BMD was higher in women than in men, while the expansion in PD was larger in men than in women. The sex difference in the normative FN bone strength data seems to be related to sex discrepancies in the development of both bone mass and geometrical parameters during both growth and adulthood.

A hip analysis protocol for pediatric bone densitometry: the Iowa Bone Development Study

Pediatric proximal femur dual-energy X-ray absorptiometry (DXA) scans present analytic challenges because of the lack of standard points of reference in the growing skeleton. The Iowa Bone Development Study (IBDS) developed a modified pediatric-specific proximal femur analysis protocol using Hologic software. Serial DXA measurements were obtained for 214 children at approximate ages 5, 8, 11, and 13 yr. Standard analysis procedures as described by the manufacturer (Hologic default) were compared with the IBDS protocol. The IBDS protocol yielded lower but more stable results for bone area, bone mineral content (BMC), and bone mineral density for total hip, femoral neck, trochanter, and intertrochanter as a result of more precisely controlling the regions of interest. Linear regression models with body size, age, and gender as predictors were developed to examine variation in measurements. Coefficients of determination (R(2)) with the IBDS protocol were greater for each time point, demonstrating that the modified protocol was better aligned with body size. Similarly, Spearman correlation coefficients between total hip and hip subregions were consistently higher for BMC and bone area with the IBDS protocol with differences more notable among younger children. The IBDS protocol provides a reproducible method for evaluating pediatric proximal femur DXA scans during growth.

Radiological evaluation of hip joint congruency in children with cerebral palsy

BACKGROUND

Disturbed muscle balance in the hip joints of children with cerebral palsy (CP) shifts the pivoting point from the middle of the femoral head to the lesser trochanter. Forces that dislocate the femoral head progressively change acetabular shape, producing inadequate femoral head covering. The aim of the study was to carry out a radiological evaluation of hip congruency in children with CP after surgical treatment.

MATERIAL AND METHODS

The study group consisted of CP patients operated on due to lower limb dysfunction between 1988 and 2001. All patients had undergone multilevel soft tissue release. A total of 52 children reported for follow-up examinations. There were 18 patients with hemiparesis (32%), 19 with diparesis (36%), and 15 with tetraparesis (29%). The age at surgery was between 2 and 19 y.o. (average age 7.33 y.o.). Radiological evaluation of the hip joints focused on changes in the migration index and the shaft-neck angle.

RESULTS

The mean migration index before surgery was 30.4% in the group of diparetic and tetraparetic children. At the last follow-up examination, the average migration index was 32.5% on the right side and 25.6% on the left side (p>0.05). There was a statistically significant decrease in the value of the migration index in children operated on before the age of 8 years (p=0.007). In children operated on after the age of 8, the change in the migration index value did not exceed 0.5% (p>0.05).

CONCLUSIONS

1. The mean migration index did not change significantly in the study group of surgically treated CP children. 2. Surgery had no influence on the shaft-neck angle 3. Surgery prevented progression of the migration index.

[Pemberton acetabuloplasty for treating the developmental dislocation of hip joint]

OBJECTIVE

To study advantages of Pemberton acetabuloplasty for the treatment of developmental dislocation of hip joint.

METHODS

Among 106 children (116 hips) with development dislocation of hip joint treated by Pemberton acetabuloplasty, 19 patients (29 hips) were boy, and 87 patients (87 hips) were girl, 46 hips were left side, 50 hips were right side and 20 hips were double side, ranging in age from 18 months to 13 years, with an average of 7 years and 3 months. All the 116 hips were treated with Pemberton acetabuloplasty, or "complete operation", which included the cutting of adductor and iliopsoas, Pemberton acetabuloplasty combined with subtrochanteric femoral shortening and rotation osteotomy. Among the hips, 95 hips were treated with simple Pemberton acetabuloplasty, and the other 21 hips were treated with complete operation. All the patients with bilateral developmental dislocation of hip joint were performed the operation at one side firstly, and one year later the other side were performed and the plate fixation in the first operation were removed.

RESULTS

All the patients were followed-up ranging from 2 to 10 years, with an average of 6 years. According to Muller and Seddon's evaluation criteria, 67 hips got an excellent result, 34 good, 10 fair and 5 bad, the excellent and good rate was 87%.

CONCLUSION

Pemberton acetabuloplasty is suitable for the treatment of developmental dislocation of hip joint in children at different ages, and the therapeutic effects are good.

Natural history of type III growth disturbance after treatment of developmental dislocation of the hip

BACKGROUND

Type III growth disturbance (T3GD) following reduction for developmental dysplasia of the hip (DDH) is a relatively rare, but potentially devastating complication. This study evaluated the long-term outcomes of patients treated for DDH who developed a T3GD hip compared to those who didn't, with an emphasis on possible risk factors.

METHODS

A case-control design was used. All radiographs of a consecutive set of patients with DDH were evaluated. Twenty-two patients (29 hips) developed T3GD. The control group consisted of 57 patients (72 hips) without any sign of growth disturbance. Variables examined included age at reduction, type of reduction and serial radiographic parameters reflecting pre- and post-reduction status. Average age at final follow up was 26 years in the T3GD group and 34 years in the control group.

RESULTS

Evidence of T3GD was first noticed radiographically at 11 months after reduction and healing of the epiphysis occurred an average of 8.5 months later. Univariate analysis demonstrated no increased risk of T3GD related to age at presentation, presence or absence of the ossific nucleus, type of reduction, initial acetabular index or Smith's centering ratios. However, the Tönnis grade was significantly associated with an increased risk of T3GD. Tönnis grade 4 hips (high-degree dislocations) had 3.43 times greater risk of developing T3GD compared to those with lower dislocations. At maturity, 90% of the T3GD hips were classified as Severin III/IV, compared to 35% of the controls. At last follow-up, 7 of the 29 T3GD hips (32%) had undergone total hip replacement at an average age of 39 years (range 19 to 57 years).

CONCLUSIONS

T3GD remains the most severe and devastating complication after treatment of DDH in children. In most cases, poor acetabular development and flattening of the femoral head lead to early degenerative changes in the hip joint. The risk increases in high-degree dislocations, independent of the treatment performed.

[X-ray morphological study of the hip joints in children of pre-school age]

Age characteristics of the ossification of hip joints were studied at the stage of their most active formation in children aged under 6 years using radiographical archive documents (1898 hip arthrograms in direct projection). According to our observations, the ossification of the femoral caput in modern children begins at the age of 3 to 5 months (88.6%--1158 cases), which is earlier than previously reported (from 6 to 12 months). In addition, we have studied in detail all the variants of the ossification of the femoral caput, such as: the fragmented center of ossification (3.6%--68 cases), various sizes of ossification centers on the right and on the left sides (11.4%--216 cases), an eccentric position of the center of ossification in the cartilaginous caput (2.1%--40 cases). Sex differences in the formation of acetabulum roof were described for the first time: the acetabulum angle in girls proved to be 3-4 degrees larger than that in boys (91.9%--1746 cases). Thus, our studies made it possible not only to update the information on the age osteology of this part of the skeleton, but also to define the variants of the individual features of ossification as well as to detect the signs of sex determination in the formation of hip joints in pre-school children.

Normal reference values of Southwick's anteroposterior angle in prepubertal and pubertal normal adolescents

Measurement of the Southwick's anteroposterior (AP) angle (shaft epiphysis proximal femoral AP angle) is not only a useful tool for planning the surgical treatment of deformities caused by slipped capital femoral epiphysis, but seems to be also important for recognizing the risk of epiphysiolysis development in obese patients (increased AP angle) or to confirm the diagnosis of slipped capital femoral epiphysis (decreased AP angle). To establish normal reference values of the Southwick's AP angle, we studied 97 normal nonobese adolescents (42 females, 55 males), with ages ranging between 8 and 16 years. The mean (SD) AP angle was 151.2 (5.0), ranging from 140 to 164. The limits for the first (p25) and third (p75) quartiles were 148 and 155, respectively. No difference was observed in the AP angle in males when compared with females. The AP angle was evaluated according to sex, chronological age, bone age, weight, height, and pubertal stage of development. We observed an inverse correlation of the AP angle with chronological age (r=-0.57) and bone age (r=-0.52). A weak inverse correlation was also found with stature (r=-0.33). Only a tendency toward an inverse correlation with weight (r=-0.27) or body mass index (r=-0.26) was observed. No significant correlation with the pubertal stage was found. When chronological and bone ages were divided into intervals, a significant reduction of the AP angle was observed only in patients older than 14 years compared with those younger than 10 years of age. In this study, we propose that the AP angle should be considered to be normal if it varies between 148 and 155. We conclude that the normal AP angle does not depend on sex; however, it tends to decrease with stature, and chronological and bone ages. In the normal weight range also, the AP angle decreases, contrasting with our previous findings in obese adolescents, in which the AP angle increases with the severity of obesity.

Variation in mammalian proximal femoral development: comparative analysis of two distinct ossification patterns

The developmental anatomy of the proximal femur is complex. In some mammals, including humans, the femoral head and greater trochanter emerge as separate ossification centres within a common chondroepiphysis and remain separate throughout ontogeny. In other species, these secondary centres coalesce within the chondroepiphysis to form a single osseous epiphysis much like the proximal humerus. These differences in femoral ontogeny have not been previously addressed, yet are critical to an understanding of femoral mineralization and architecture across a wide range of mammals and may have key implications for understanding and treating hip abnormalities in humans. We evaluated femora from 70 mammalian species and categorized each according to the presence of a 'separate' or 'coalesced' proximal epiphysis based on visual assessment. We found that ossification type varies widely among mammals: taxa in the 'coalesced' group include marsupials, artiodactyls, perissodactyls, bats, carnivores and several primates, while the 'separate' group includes hominoids, many rodents, tree shrews and several marine species. There was no clear relationship to body size, phylogeny or locomotion, but qualitative and quantitative differences between the groups suggest that ossification type may be primarily an artefact of femoral shape and neck length. As some osseous abnormalities of the human hip appear to mimic the normal morphology of species with coalesced epiphyses, these results may provide insight into the aetiology and treatment of human hip disorders such as femoroacetabular impingement and early-onset osteoarthritis.

Computed tomographic evaluation of growth-related changes in the hip joints of young dogs

OBJECTIVE

To evaluate changes in canine hip joint characteristics during growth via computed tomography (CT) and compare CT features of hip joints with and without laxity in young dogs placed in 2 imaging positions.

ANIMALS

21 dogs (42 hip joints).

PROCEDURES

From 2 to 12 months after birth, CT examinations of the acetabulum of each hip joint in simulated normal standing and simulated weight-bearing positions were performed monthly for all dogs. Acetabular angle, dorsal acetabular rim angle (DARA), and femoral head diameter (FHd) were analyzed as skeletal variables; the lateral center edge angle (LCEA), dorsolateral subluxation (DLS) score, and center distance (CD) index were analyzed as joint laxity variables. At 12 months, all dogs underwent the Ortolani test to as-sess hip joint laxity.

RESULTS

Hip joint laxity was detected in 5 dogs (10 joints) at 12 months of age; from 2 months, the acetabular angle and FHd increased and DARA decreased significantly until 5 months and the LCEA and DLS score increased significantly until 6 months. In nonlax hip joints in both positions, the CD index decreased significantly until 4 months of age and be-came stable thereafter. In lax hip joints, the CD index increased from 4 through 12 months; between 8 and 12 months, these changes were significantly greater in the weight-bearing position than in the standing position.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggest that CT-detected abnormalities in the DARA and CD index during body weight loading might be useful indicators of hip dysplasia in 2- to 6-month-old dogs.

[The natural history of acetabular development in developmental dysplasia of the hip]

Normal hip joint development requires a genetically determined balance of growth between the acetabular and triradiate cartilage, and a well-centered femoral head. It is unclear how and why this delicate balance becomes disrupted, leading to abnormal development of the hip joint. It is known that, without treatment, a certain number of hips will become problematic later in life. This article outlines normal hip joint development and discusses the natural history of acetabular development in developmental dysplasia of the hip (DDH). The natural history of DDH depends on many factors including age of diagnosis, the growth capacity of the involved structures, and the effects of treatment interventions. Early identification and treatment of hip instability maximizes the chance for normal hip development to occur. However, close observation of the child is crucial to identify individuals where normal development is not occurring. Intervention may become necessary in certain situations to positively affect hip joint development.

[Pavlik's method in developmental dysplasia of the hip]

One of the worst complications following treatment of developmental dysplasia of the hip is avascular necrosis. In the first half of the 20th century, the incidence of this problem reached up to 30% of treated children. To avoid this complication, Arnold Pavlik developed a new method in the late 1940s and called it a dynamic approach to treatment, which was based on the ingenious idea that the hip is an organ of movements and needs movement to be healed. Healing is accomplished by using stirrups as an aid to attaining flexion of the hips and knees, whereby the child achieves a normal hip nonviolently by himself. Pavlik's method spread slowly throughout the world and this literature review points out problems with this method, and summarizes the rates of success achieved and avascular necrosis reported by various authors.

Developmental dysplasia of the hip: nursing implications and anticipatory guidance for parents

Developmental dysplasia of the hip (DDH) is a comprehensive term used to describe an abnormal relationship between the femoral head and the acetabulum. Developmental dysplasia of the hip includes a very wide spectrum of abnormality from a frank dislocation (very unstable) to a stable hip with a slightly shallow acetabulum. As many of these findings may not be present at birth, the term developmental more accurately reflects the biologic features than does the term congenital. Despite the recent increased awareness of DDH and the importance of thorough screening programs, hip dysplasia continues to be a frequently missed diagnosis in pediatrics. Earlier detection and diagnosis of DDH is associated with a much more successful and less invasive outcome.

Development of the hip joints in unoperated children with cerebral palsy: a radiographic study of 76 patients

BACKGROUND

The aims of the present study were to assess the development of hip dysplasia in children with bilateral spastic cerebral palsy and to evaluate the factors that influence the progression.

PATIENTS AND METHODS

76 children, 42 with spastic quadriplegia and 34 with diplegia, were included in the study. Their mean age at the first radiographic examination was 3.5 (1-11) years. The patients were followed up until operative treatment (54 subjects) or until the most recent radiograph in those who did not undergo hip surgery. The mean length of follow-up was 4.8 (1-13) years. On the initial and most recent radiographs, the migration percentage (MP) was measured, which is the percentage of the femoral head lateral to the acetabular rim.

RESULTS

The mean MP of the side with the largest displacement was 25% (-18-66) at the initial radiographic examination and 51% (9-100) at the last follow-up. The mean increase in MP was 7% (-2-33) per year. Linear multiple regression revealed that gait function and age were the most important variables that influenced the rate of MP progression. Children who could not walk had significantly greater MP progression per year (12%) than those who walked with or without support (2%). In the quadriplegics, the maximal yearly increase in MP was 13% under 5 years of age and 7% in older children. This difference was statistically significant, whereas no significant difference in relation to patient age was seen in the diplegics.

INTERPRETATION

There is a pronounced trend towards displacement of the hips in quadriplegic CP patients who are under 5 years of age and cannot walk. Because hip dislocation may lead to severe problems, close follow-up is important in finding the appropriate time for hip surgery in order to avoid progression towards dislocation. The risk of severe hip dysplasia is considerably less in spastic diplegia.

Longitudinal study of normal hip development by ultrasound

In the management of a newborn's hips, ultrasonography has proven to be useful. The progression of measurements at different ages in normal hips has not been thoroughly investigated. The purpose of this prospective study was to assess the longitudinal development of clinically stable hips. Forty newborns (80 hips) were assessed by ultrasonography at birth and at 6 and 12 weeks of age. Femoral head coverage (FHC), alpha angles, and beta angles were measured. The results showed a significant change in values between the three points in time for all measurements (P < 0.001). The mean FHC progressed from 58.4% to 65.6% to 69.3%, the mean alpha angle from 70.2 degrees to 76.8 degrees to 80.3 degrees , and the mean beta angle from 52.1 degrees to 45.7 degrees to 42.9 degrees . In clinically stable hips, the FHC and alpha and beta angles change significantly over time; therefore, it is important to consider the child's age when interpreting ultrasound images.

Surgical treatment of late developmental displacement of the hip. Results after 33 years

The outcome of displaced hips treated by Somerville and Scott's method was assessed after more than 25 years. A total of 147 patients (191 displaced hips) was reviewed which represented an overall follow-up of 65.6%. The median age at the index operation was two years. During the first five years, 25 (13%) hips showed signs of avascular change. The late development of valgus angulation of the neck, after ten years, was seen in 69 (36%) hips. Further operations were frequently necessary. Moderate to severe osteoarthritis developed at a young age in 40% of the hips. Total hip replacement or arthrodesis was necessary in 27 (14%) hips at a mean age of 36.5 years. Risk factors identified were high dislocation, open reduction, and age at the original operation. Two groups of patients were compared according to outcome. All the radiographic indices were different between the two groups after ten years, but most were similar before. It takes a generation to establish the prognosis, although some early indicators may help to predict outcome.

[The hip joints of preterm neonates in sonographic evaluation]

The introduction of sonography to the evalution of the hip joint, allowed for the non-invasive examination in preterm neonates and thus assessment of the development their hip joints. MATERIAL AND METHODS. The examined group consisted of 143 preterm neonates with the body weight by delivery lower then 2000 grams (286 hip joints) and the control group of 31 children from term delveries forming the control group. The sonographic examination was conducted stricktly according to the rules presented by Graf. First examination was performed averagely in the 3rd week of life, second avg. in the 14th, third in avg. the 23rd, fourth avg inthe 33r week of life. Wyniki. In the first examination, done in the 3rd week of life it was noticed that highest rate of the hips Ia appeared in the group I (newborns with the lowest bogy weight), and together with the increase in body weight the incidence of such hips decreased, when the incidence of type IIa hips increased at the same time. At the final examination no statistically significant differences were found between the hip joints and no dysplastic hips were found. Wnioski. According to our results, we found that preterm delivery is not a risk factor for the developmetal hip dysplasia.

[Artificial contrasting of the hip joint in children and adolescents: X-ray anatomic study]

The diagnostic capacities of currently available radiation diagnostic techniques in imaging some anatomic structures of the hip joint (HJ) were determined on the basis of studies of 70 sectional sets of HJs in children and adolescents aged 0 to 13 years through X-ray and anatomic comparisons. Magnetic resonance imaging (MRI) is the method of choice in visualizing the cartilaginous and soft-tissue structures of HJ in children and adolescents. MR-arthrography extends the capacities of the technique in imaging the articular surfaces and intraarticular structures of the joint. Contrast enhancement of the HJ cavity during X-ray study and computed tomography may be an alternative to MRI as it makes it possible to well visualize the cartilaginous head of the femur, the cartilaginous borders of the cotyloid cavity, the limbus, etc. Double contrasting enhances the capacities of detailed imaging of the articular surfaces, intraarticular structures, capsules, and ligamentous apparatus of HJ. The studies performed have specified the time course of anatomic changes during HJ growth and defined the method of choice or an alternative procedure of radiation techniques in the diagnosis of these changes, which is of great importance for early detection of pathological changes and for choice of therapeutic and diagnostic policy.

Nutrition influences skeletal development from childhood to adulthood: a study of hip, spine, and forearm in adolescent females

This study evaluated the long-term efficacy of supplemental calcium and dairy products on bone mineral areal density of the hip and spine and on the bone geometry and volumetric bone mineral density of the forearm in young females during late adolescence. The study was conducted among participants of a randomized double-blinded, placebo-controlled clinical trial with calcium supplements and among participants of an observational study with higher consumption of dairy products. Hip and spine measurements by dual-energy X-ray absorptiometry were done every 6 mo (dairy group every 12 mo) during last 3 y of the follow-up while peripheral quantitative computerized tomography of the forearm was done at the last visit. The results of the study show a positive influence of calcium supplementation and dairy products on bone mineral density of the hip and the forearm. Dairy products were also associated with a higher bone mineral density of the spine while calcium supplementation did not have an effect. Calcium exerts its action on bone accretion during growth primarily by influencing volumetric bone mineral density while milk may have an additional impact on bone growth and periosteal bone expansion.

Radiographic parameters of the hip joint from birth to adolescence

BACKGROUND

Various qualitative and quantitative radiological geometrical parameters can be of great help when assessing dysplasia of the hip joint and in understanding developmental processes of the infant hip. There are few data on the normal values of the hip joint at different ages.

OBJECTIVE

To perform radiographic measurements on hip joints considered to be anatomically normal and to provide data for each age group, thus describing features of the radiographic development of the hip.

MATERIALS AND METHODS

Radiographs were examined from 355 children (age 0-16 years) undergoing examination for scoliosis (long film), urography or plain abdominal radiography. Qualitative and quantitative signs were observed and measured, focusing on the Hilgenreiner, Wiberg and Idelberger angles and the decentric distance.

RESULTS

Before the age of 9 years measurable data from neighbouring age groups differed significantly, indicating typical radiological changes of the joint. For the same age range, qualitative changes could also be observed. After 9 years of age, radiological development of the normal hip joint during childhood is much slower.

Evaluation of ultrasonographic angle and linear parameters in the diagnosis of developmental dysplasia of the hip

Angle parameters proposed by Graf and linear parameters introduced by Morin are the most common currently in use for quantification and classification of ultrasonographic findings in the diagnosis of developmental dysplasia of the hip. The aim of this study was to determine which of the two parameters is more suited to routine clinical use. Investigation was carried out on 100 hips of 50 infants by the same examiner who obtained two separate sonograms for each hip. Based on the results of our study, angle parameters appear to be more functional in identifying and classifying pathology, and more adequate for screening and diagnosis.

[Normal values of several acetabular angles on hip radiographs obtained from individuals living in the Eskişehir region]

OBJECTIVES

To determine the normal values of several radiographic acetabular angles in individuals of Eskişehir region.

METHODS

The acetabular index (AI) angle, acetabular angle (AA) of Sharp and the ACM angle were measured in 1162 normal hips (n=581, 251 males, 330 females; mean age 33 years; range 5 to 75 years). For AI angle, Hilgenreiner's line and the line connecting the lower end points of the sclerotic lines of the acetabular roofs were used for reference in subjects between five to 11 years with an open Y cartilage and in those with closed Y cartilage, respectively. AA and ACM angles were measured by the same method in all subjects.

RESULTS

The mean AI angle between 5-11 years was 12.9+/-4.5 degrees; the upper normal limit for the Hilgenreiner's AI angle was derived as 22 degrees. The mean AI angle above age 11 was 3.3+/-4.7 degrees and the upper normal limit for the AI angle defined by Tönnis after age 11 was found as 13 degrees. Significant linear correlations were found between the AI angle and age for 5-11 years (p=0.002) and above 11 years (p=0.001), respectively. The mean AA angle was 39.2+/-4.6 degrees. There was a significant linear correlation between the AA angle and age (p=0.001). The upper limits for the AA angle in normal juvenile, adolescent, and adult hips were found as 52 degrees, 49 degrees, and 45 degrees, respectively. The mean ACM angle was 41.9+/-3.3 degrees. A significant linear correlation was observed between the ACM angle and age (p=0.001). The upper limit for the ACM angle in normal hips was assessed as 49 degrees in all age groups.

CONCLUSION

The authors of this study propose that the normal limits of acetabular angles obtained from our own population be used as reference values in interpreting standard radiographs of the hip.

Perinatal development of the rat hip joint with restrained fetal movement

We compared the structures of the femoral head (FH) of neonates between normal and operated legs with restrained fetal movement using an exo utero technique. At embryonic day (E) 16.5, one hind limb was sutured onto the embryonic membrane and the fetuses were allowed to develop exo utero until the term (E22.5). There was no significant difference in the largest diameter of the FH between the non-operated and operated side FH in the operated neonates and the FH of the non-operated neonates. By scanning electron microscopy, roughness and collagen fiber bundles, which were detected on the surface of the operated side FH at E18.5, disappeared at E22.5. However, the operated side FH was deformed and the surface cell arrangement was more irregular than that of the controls at E22.5 by light microscopy. These results suggest that the abnormality of cell arrangement caused by the restraint of fetal movement may induce the deformity and irregularity of the FH surface, although this operation may not disturb the basic cellular activities such as cell proliferation as well as the secretion of cartilage ma-trix and collagen fibers. To further investigate the recovery process in the operated newborns after releasing the restraint, we bred them artificially for a considerable period after birth. The operated side FH surface of the neonate bred for 45 hours was smoother than that at E22.5 and similar to that of the non-operated side FH. This result suggests that the proper movement of the extremities after birth may recover the deformity caused by restrained fetal joint movement.

Development of the femoral bicondylar angle in hominid bipedalism

The bicondylar angle is the angle between the diaphysis of the femur and a line perpendicular to the infracondylar plane. The presence of a femoral bicondylar angle in Australopithecus afarensis indicates that these 3.5-million-year-old hominids were bipedal. Many studies have linked the formation of the femoral bicondylar angle with bipedality, but the mechanism for the formation of the angle is poorly understood. Mechanical factors, such as stresses and strains, influence the growth process. In particular, previous studies have demonstrated that hydrostatic compressive stress inhibits growth and ossification, and octahedral shear stress promotes growth and ossification. In this study we implemented these mechanobiological principles in a three-dimensional finite-element model of the distal femur. We applied loading conditions to the model to simulate loading during the single-leg stance phase of bipedal gait. The stresses in the physis of the distal femur that result from bipedal loading conditions promote growth and ossification more on the medial side than on the lateral side of the femur, forming the bicondylar angle. This model explains the presence of the bicondylar angle in hominid bipedalism and also the ontogenetic development of the bicondylar angle in growing children. The mechanobiological relationship between endochondral ossification and mechanical loading provides valuable insight into bone development and morphology.

The natural history of developmental dysplasia of the hip after early supervised treatment in the Pavlik harness. A prospective, longitudinal follow-up

Between June 1988 and December 1997, we treated 332 babies with 546 dysplastic hips in a Pavlik harness for primary developmental dysplasia of the hip as detected by the selective screening programme in Southampton. Each was managed by a strict protocol including ultrasonic monitoring of treatment in the harness. The group was prospectively studied during a mean period of 6.5 +/- 2.7 years with follow-up of 89.9%. The acetabular index (AI) and centre-edge angle of Wiberg (CEA) were measured on annual radiographs to determine the development of the hip after treatment and were compared with published normal values. The harness failed to reduce 18 hips in 16 patients (15.2% of dislocations, 3.3% of DDH). These required surgical treatment. The development of those hips which were successfully treated in the harness showed no significant difference from the normal values of the AI for the left hips of girls after 18 months of age. Of those dysplastic hips which were successfully reduced in the harness, 2.4% showed persistent significant late dysplasia (CEA <20 degrees) and 0.2% persistent severe late dysplasia (CEA <15 degrees). All could be identified by an abnormal CEA (<20 degrees) at five years of age, and many from the progression of the AI by 18 months. Dysplasia was considered to be sufficient to require innominate osteotomy in five (0.9%). Avascular necrosis was noted in 1% of hips treated in the harness. We conclude that, using our protocol, successful initial treatment of DDH with the Pavlik harness appears to restore the natural development of the hip to normal. We suggest that regular radiological surveillance up to five years of age is a safe and effective practice.

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.

Magnetic resonance imaging analysis of hip joint development in patients with diastrophic dysplasia

The authors used magnetic resonance imaging to evaluate the hip joint in patients with diastrophic dysplasia. T1- and T2-weighted images were obtained from 35 patients (25 female patients, 10 male patients) of different ages (1-39 years). The status of the joint and paraarticular soft tissues was evaluated. Hip joint congruity was good, although the joint was usually deformed. The thickness of the joint cartilage was diminished and signs of early osteoarthritis, including bone cysts and local edema, were common. The ligamentum teres was visible in only 24% of patients, suggesting abnormality of the ligamentous structures. Epiphyses were flattened or absent in all young patients. Of the 17 visible epiphyses, 7 showed avascular necrosis, indicated as a decrease in signal intensity in both T1- and T2-weighted images. It seems that proximal femoral epiphysis fails to bear normal weight pressure.

Lower femoral neck bone mineral density in prepubertal former preterm girls

The purpose of this case-control study was to determine bone mineral content and areal bone mineral density at various skeletal sites in former preterm girls, aged 7-9 years, and to compare these data with age-matched term controls. Subjects included 25 white, prepubertal, former preterm girls (gestational age 30.8 +/- 0.3 weeks, birthweight 1461 +/- 56 g [mean +/- SEM]). Controls included 50 healthy, white, prepubertal girls born at term and matched for age (two controls per case). Measurements included anthropometric variables, calcium intake according to a food-frequency questionnaire, bone mineral content (BMC; grams), and areal bone mineral density (aBMD; grams per square centimeter), using dual-energy X-ray absorptiometry (DXA) at six skeletal sites. Thirteen preterm girls and 13 age-matched term controls were reassessed 1 year after the first DXA measurement. The former preterm girls were similar to controls in terms of age and height, but were lighter (24.6 +/- 0.6 vs. 27.0 +/- 0.6 kg, p = 0.02). They also reported a higher median calcium intake (1058 vs. 759 mg/day, p = 0.004). aBMD was lower in former preterms compared with controls at the level of the radial metaphysis (0.283 +/- 0.006 vs. 0.298 +/- 0.004, p = 0.04), femoral neck (0.593 +/- 0.011 vs. 0.638 +/- 0.010, p = 0.007), and total hip (0.596 +/- 0.012 vs. 0.640 +/- 0.010, p = 0.007), but was similar between the two groups at the radial diaphysis (0.437 +/- 0.004 vs. 0.436 +/- 0.004) and femoral diaphysis (1.026 +/- 0.015 vs. 1.030 +/- 0.011). Femoral neck aBMD remained lower compared with controls in the subgroup of preterm girls reassessed after 1 year (0.608 +/- 0.017 vs. 0.672 +/- 0.020, p = 0.02). In random effects models for longitudinal data, taking into account the effects of age, weight, and height on aBMD (dependent variable), femoral neck aBMD remained lower in former preterms (p < 0.001). Prepubertal former preterm girls showed growth recovery, but had lower aBMD at the hip and radial metaphysis than age-matched term controls, despite spontaneously higher calcium intake. Preterm girls had similar aBMD results compared with controls at sites with predominantly cortical bone (radial and femoral diaphysis), which are known to be more sensitive to calcium intake.

Hip dysplasia in bilateral cerebral palsy: incidence and natural history in children aged 18 months to 5 years

Children with bilateral cerebral palsy (CP) born during 1989 to 1992 (n=346) to a geographically defined population were ascertained and followed up to age 5 years. The aims of the study were to monitor hip development by serial X-rays; to record gross locomotor development, aspects of physical management, and any hip-related orthotics or surgery; to learn more of the natural history of hip development in this condition; and to provide guidelines for a surveillance protocol for those clinically managing children with bilateral CP. Children were X-rayed at 18, 24, 30, 48, and 60 months. X-rays were taken in a standardized position and measured to record migration percentage, acetabular index, Sharp's angle, and Smith's diaphyseal ratios. Relationships between the measures were investigated and a natural history of the children's hip development suggested. At as early as 18 months, migration percentages were significantly greater than in the normally developing population, although no measured CP factor could be identified to be the cause of this early change. Two possible factors affecting early hip development are described, neither of which is clinically apparent: the first separates the bilateral CP population as a whole from the normal population; but there is an additional presdisposing factor affecting some children only which in the presence of the motor disorder, has a significant influence on early hip development and subsequent dysplasia. The study confirms that, when measured correctly, migration percentage is the best guide to hip surveillance and the need for treatment. It is suggested that all children with bilateral CP should be X-rayed in a standardized position at 30 months (corrected for gestational age).

Radiographic imaging for treatment and follow-up of developmental dysplasia of the hip

Developmental dysplasia of the hip (DDH) is a spectrum of abnormalities that can range from a very mild disturbance to a very severe process that is incapacitating later in life. This article considers the causative factors and natural history of DDH, as well as anatomic abnormalities, physical examination findings, and both surgical and nonsurgical treatment options. The goal of this article is to place in perspective the use of advanced imaging techniques in the diagnosis and follow-up of patients with DDH. Ultrasound, computed tomography (CT), and magnetic resonance (MR) findings are reviewed with respect to the diagnosis of DDH, treatment complications, and long-term problems that may occur in treated and untreated patients.

Hydroxyapatite-coated total hip arthroplasty in osteoporotic patients

A prospective review was performed on 22 osteoporotic patients (rated from 1 to 3 on the Singh Index) with hydroxyapatite-coated total hip replacements. These results were compared with a control group (Singh Index 4 to 6) of 45 patients (48 hips) with respect to clinical and radiographic data. Surgery was performed over a six-year period (1991 to 1996) and the time to follow-up evaluation averaged 5 years (range: 2 to 7 years). All patients, in both groups, were over 65 years old with an average age of 71 and 73 years, respectively. The pre-operative diagnoses and Harris hip scores were also similar for both groups. Clinical evaluation was based on the Harris Hip score and radiographic evaluations using Engh's criteria. There was no significant difference between the final average Harris hip score in the osteoporotic bone group, which was 87 points, and that for the control group, which was 91 points (p > 0.05). Radiographic evaluation demonstrated confirmed bone ingrowth in most patients in each group; one patient in each group had suspected bone ingrowth. No stems were revised for aseptic loosening and no endosteal lysis was found. Progressive bone formation was seen around the femoral stem proximally. The acetabular components demonstrated no sign of mechanical loosening or osteolysis. Bone formation was found in most patients in zone I, and in a few patients also in zone III. On the basis of the results of this study, it is believed that osteoporotic bone as a factor by itself should not compromise the early results of hydroxyapatite total hip arthroplasty and should provide good results in the long term.

The hip joint: the fibrillar collagens associated with development and ageing in the rabbit

The fibrillar collagens associated with the articular cartilages, joint capsule and ligamentum teres of the rabbit hip joint were characterised from the 17 d fetus to the 2-y-old adult by immunohistochemical methods. Initially the putative articular cartilage contains types I, III and V collagens, but when cavitation is complete in the 25 d fetus, type II collagen appears. In the 17 d fetus, the cells of the chondrogenous layers express type I collagen mRNA, but not that of type II collagen. Types III and V collagens are present throughout life, particularly pericellularly. Type I collagen is lost. In all respects, the articular cartilage of the hip joint is similar to that of the knee. The joint capsule contains types I, III and V collagens. In the fetus the ligamentum teres contains types I and V collagens and the cells express type I collagen mRNA; type III collagen is confined mainly to its surface and insertions. After birth, the same distribution remains, but there is more type III collagen in the ligament, proper. The attachment to the cartilage of the head of the femur is marked only by fibres of type I collagen traversing the cartilage; the attachment cannot be distinguished in preparations localising types III and V collagens. The attachment to the bone at the lip of the acetabulum is via fibres of types I and V collagens and little type III is present. The ligament is covered by a sheath of types III and V collagens. Type II collagen was not located in any part of the ligamentum teres. The distribution of collagens in the ligamentum teres is similar to that in the collateral ligaments of the knee. Its insertions are unusual because no fibrocartilage was detected.

[An analysis of the selected parameters of the normal hip joint during growth in magnetic resonance imaging]

Dynamics of the selected parameters of the normal hip joint during growth has been presented. Fifty-three normal hips in 40 individuals aged 3-17 years were assessed with Magneton Impact MRI. The angles and indices were found on T1 coronal images in Spin Echo or Turbo Spin Echo sequence. Acetabular roof angle of Hilgenreiner, acetabular inclination angle of Sharp, Wiberg angle and Heyman-Herndon index were calculated with both bony and cartilaginous elements regarded. Parameters based on cartilaginous parts of the joint did not change during normal growth, but they do change if calculated with the use of bony landmarks reaching Acartilaginous values by the age of 14-15. The results suggest, that during growth gradual ossification of cartilaginous elements takes place but the proportions remain unchanged. The investigation determines the age of enhanced ossification and the age of its termination.

[Radiologic morphometry of the hip in Beninese black children]

PURPOSE

The author aims to objectivize simple parameters of normal anatomy of the hip related to age and sex in children as a contribution to interpretation criterions in medical imagery. Materials and methods. He has examined antero-posterior radiographs of 155 normal hips (right: 81; left: 74) among 129 children aged from six months to 16 years (mean age=8.9 years). They were 86 boys and 43 girls (ratio M/F=2).

RESULTS

The results are as follow:--the joint space of the hip (JS/H): cranial part (cranial joint space: CJS/H): 5.5 mm +/- 0.5; medial part (medial joint space: MJS/H): 7 mm+/-0.5; --the bony roofingless part of the femoral head (BR/FH): 1-6 years: 1-3 mm; 7-13 years: 4-5 mm; 14-16 years: 6 mm; --the neck shaft angle of the femur (NSA/F); 1-6 years: 150 degrees-140 degrees; 7-16 years: 135 degrees; --the horizontal and the vertical diameters of the femoral head (HD/FH; VD/FH); x being the age of the children, the HD/FH grows according to a linear regression function as Ydh = 2x + 13+/-2 and the VD/FH as Ych = 2x + 18+/-2; --the centre acetabular edge index (CEI): the CEI decreases from 1 to 16 years: medium: 2.75-1.77; maximum: 2.31-1.67; minimum: 3.62-1.91; --the centre-acetabular cartilage index (CCI)): the CCI grows from 1 to 16 years: medium: 0.57-0.70; maximum: 0.62-0.73; minimum: 0.5-0.68. No influence of the side of the hip nor the sex of the children is observed.

CONCLUSION

This study brings out exhaustive and original data on the growth velocity of the hip skeleton in children and supplies with criterions of diagnosis according to age in childhood.

[Development of the normal infantile hip joints assessed by MRI]

The paper provides an overview of the time of appearance of the secondary ossification centers and closure of the growth plates of the acetabulum and proximal epiphysis of the femur: the triradiate cartilage, the acetabular roof growth cartilage, the subcapital growth cartilage, the growth cartilage of the major trochanter, the growth cartilage of the minor trochanter. The study is based upon 62 MRI scans of healthy hips in 45 patients aged 3-21. The examined hips showed no pathologic traits--neither in the MRI scan nor in X-ray investigation. In Spin Echo and Turbo Spin Echo sequential imaging all obtained slices were used, on GRADIENT ECHO: FISP 3D, FLASH 2D, and FLASH 3D FAT SAT only chosen slices were included in the study. This way the following results were obtained: the ossification center of the major trochanter appears at the age of 3 in girls and at the age of 6 in boys, while the ossification center of the minor trochanter appears at the age of 6 in both sexes. The times of complete ossification of following growth cartilages were observed: for the triradiate cartilage ossification was observed at age 12-15 in girls and 15-16 in boys; for the cartilage of the acetabular roof ossification was noted at age 12-15 in girls and 15-18 in boys; ossification in the subcapital growth cartilage occurred at age 15-17 in girls and 16-18 in boys; the major trochanter growth cartilage ossifies at age 15-16 in girls and 16-18 in boys; for the minor trochanter ossification of the growth cartilage occurs at age 14-16 in girls and at age 16-18 in boys. The secondary ossification center of the pubic bone appears at age 9-11 in girls and 13-16 in boys and the secondary ossification center of the acetabular roof appears at age 13-17 in girls and boys. This study expand our knowledge on the development of the hip joint and facilitate the assessment of hip pathology.

Echosonogrametric diagnosis of developmental dysplasia of the hip

In view of adding to ultrasonographic scanning of the neonatal hip through various projections and in order to improve the measurement and quantification base of the normal and dysplastic neonatal hip, the research was conducted on anatomic hip preparation of full-term still-born baby. The research on a clinical sample covered 600 ultrasonically examined normal and dysplastic hips. Ultrasonographic serial scanning was performed on various planes using linear transducer with 5 and 7.5 MHz and with or without a water pillow. On the clinical sample of the particular group various projections were applied and results compared with projections obtained on anatomic preparation. Concluded was that with several projections frontal sonographic projections tomographic examination of the hip joint could be performed. Better insight of the position of the femoral head at rest in neutral and flexed positions, the relative stability of the hip with motion and stress and the depth and configuration of the bony and cartilaginous portions of the acetabulum could be obtained if, besides frontal sections, cross sections of the hip were used. Sufficient measurement data echosonogrametric parameters were indispensable for an adequate definition of all hip joint structures.

[The acetabular labrum in infants]

The knowledge of embryology and early development of the hip joint (and especially the "Anlage" of the acetabular labrum) is necessary to correctly understand further growth disturbances and developmental dysplasias and dislocations of the hip joint. "Teratologic" luxations--based on damages of the fetal "Anlage"--should be distinguished from "developing deformations" of originally normal-shaped hip joints. By using modern imaging techniques, especially sonography and MRI, the morphologic relationships of the acetabular labrum in centered and decentered hip joints could be clarified. The tip and the basis of the labrum and their relations with the hyalin-preformed growth zone cartilage of the acetabular roof are changing during the process of decentering and can be clearly visualized by sonographic means. To understand the morphologic changes in decentered hip joints, a clear and consistent terminology should be used: The term "limbus" is misleading and should be avoided; one should use the terms "acetabular labrum" and "hyalin-preformed cartilaginous acetabular roof" for the two histologic subdivisions of the acetabular roof cartilage. We do not know much about size and shape, about nutrition and vascularity of the acetabular labrum, and only few facts about the junction zone of the labral attachment to the hyalin cartilage acetabular roof, and so on. We also do not have any clear evidence about possible micro-damages of the labral-capsular-complex during successful closed reduction and their sequelae in childhood and adolescence, possibly being one cause of labral lesions in adults. Further basic research in this field seems useful and necessary.