Femoral Head In Children Research Articles

Idiopathic aseptic necrosis of the femoral head in children who are professionally engaged in gymnastics: A literature review

BACKGROUND: Aseptic necrosis of the femoral head in school-age children is a severe, rapidly progressive degenerative and dystrophic disease. A significant proportion of girls aged 10 years with osteonecrosis of the femoral head have been professionally engaged in rhythmic gymnastics. The relationship between professional sports, in particular rhythmic gymnastics, and the development of this pathology and the mechanism of impaired blood flow in the femoral head in such cases remains unclear. The severity of the course and serious consequences of this disease in the form of multidimensional deformities of the femoral head, early arthrosis of the hip joint, and persistent disability, require close attention.
 AIM: To analyze modern world literature data on the etiology, pathomechanics, and features of the course and treatment of idiopathic aseptic necrosis of the femoral head in children professionally engaged in rhythmic gymnastics.
 MATERIALS AND METHODS: A literature search on the problem of idiopathic aseptic necrosis of the femoral head in children professionally engaged in rhythmic gymnastics in the open information databases was conducted in PubMed, Science Direct, and Library with an analysis depth of 20 years.
 RESULTS: The analysis of publications on the osteonecrosis of the femoral head allowed us to talk about the etiological connection of this condition with professional rhythmic gymnastics, namely, high-intensity repetitive loads on the hip joint of a child. Studies using in vivo laser Doppler flowmetry and 3D computer modeling prove the occlusion of blood vessel branches encircling the femur under excessive mechanical stress on the femoral head and potentially unfavorable positions in the hip joint – overextension (hyperextension), external rotation, and abduction.
 CONCLUSIONS: Professional gymnastics can be a risk factor for the development of osteonecrosis of the femoral head. Frequent late disease diagnoses with the development of severe deformity of the femoral head and end-stage coxarthrosis requiring total hip replacement in adolescents determine the need for early identification of the causes of hip pain in children engaged in gymnastics. The findings will help improve treatment results and reduce the number of organ replacement interventions.

Legg–Calvé–Perthes disease presenting with osteoarthritis: Mechanisms of the development and prospects of conservative therapy using bisphosphonates

BACKGROUND: Aseptic necrosis of the femoral head in children remains a subject of great interest among specialists, despite its long history of study. The LeggCalvPerthes disease is the most common form of aseptic necrosis of the femoral head in children. The necrotic lesion in the femoral head results from the blockage of the arterial blood supply to the epiphysis, leading to its infarction. Some children experience a more aggressive disease course, with signs of osteoarthritis, which can result in the early development of coxarthrosis. Numerous publications have demonstrated the successful use of bisphosphonates in adult patients with aseptic necrosis of the femoral head.
 AIM: To generalize data on the use of bisphosphonates in children with the LeggCalvPerthes disease presenting with signs of osteoarthritis through the analysis of contemporary global literature.
 MATERIALS AND METHODS: A literature search was conducted in the open databases of PubMed, Science Direct, and Google Scholar, and the analysis depth spanned 20 years. The search terms used included LeggCalvPerthes disease, aseptic (avascular) necrosis of the femoral head, and bisphosphonates. The review encompassed the literature on bisphosphonates, their biological action, effectiveness of their use in patients with aseptic necrosis of the femoral head, and results of our research.
 RESULTS: Studies on the efficacy of bisphosphonates in children with LeggCalvPerthes disease are limited. Currently, the effect of bisphosphonates on disease course and outcome is unknown. Despite this, mechanisms of chronic inflammation are increasingly mentioned in the literature, which may directly or indirectly influence the clinical course and outcome of the disease. The key is the hyperactivity of osteoclasts in osteonecrosis. The experience of using bisphosphonates in adult patients with aseptic necrosis of the femoral head had positive results in preventing the progression of the deformity of femoral head deformity.
 CONCLUSIONS: Bisphosphonates are specific inhibitors of osteoclast activity, which has been used in many diseases. The results and inferences of using bisphosphonates in children with LeggCalvPerthes disease will lead to the formulation of a new treatment algorithm.

Risk Factors of avascular Osteonecrosis of the Femoral Head in Children at the National Reference Center for Sickle Cell Disease in Brazzaville, Congo

Introduction: The avascular osteonecrosis of the femoral head (AOFH) is a common complication of sickle cell disease (SCD). It exposes to lameness and sometimes to a very debilitating handicap. It is a source of desocialization, particularly in developing countries where prosthetic surgery remains inaccessible to the majority. This survey aimed to identify the risk of occurence AOFH.
 Materials and Methods: It was a case-control study carried between october 2017 and september 2021 at the National Reference Center for SCD « Antoinette Sassou Nguesso » in Brazzaville. It concerned 31 children with clinical and radiographic signs of AOFH. Clinical (age at diagnosis of SCD, frequency of vasoocclusive crises and hospitalization for vasoocclusive crises, number of blood transfusion) as well as hematological examination (blood count in the intercritical period) and hydroxyurea treatment were compared with those of 62 children with no clinical and radiographic signs of AOFH. The chi2 statistical test and the odds ratio were used for the comparison (P ˂ 0.05).
 Results: The sex ratio was 1.38 versus 0.93 (p = 0.50). The mean age of diagnostic of SCD was 3.76 ± 2.56 years versus 3.94 ± 2.01 years (p = 0.81). Logistic regression showed that SCD children with AOFH had a significantly higher rate of annual frequency of VOC (4.16 ± 1.18 vs 2.91 ± 1.68; P = 0.015), annual frequency of hospitalization for VOC (3.74±1.65 vs 1.45 ± 1.28; P = 0.000) and number of blood transfusions (3.38 ± 2.69 vs 2.42 ± 2.32; P = 0.03).
 Conclusion: Emphasis should be placed on the prevention and early management of acute complications of SCD. The role of hydroxyurea should be clarified by further work.

Core Decompression For Treatment of Avascular Necrosis of Femoral Head In Children With Sickle Cell Anemia

Sickle cell anemia (SCA) is a hereditary hemoglobin disorder that results in sickling of the red cell, leading to chronic hemolytic anemia, vascular occlusion and progressive organ damage. Avascular necrosis (AVN) is a known and common complication in sickle cell anemia. There are very little studies addressing core decompression of femoral neck in children with SCA. Many studies are done for adult patients. We did core decompression (CD) of femoral neck in children with AVN due to sickle cell anemia .39 hips in 29 patients are done between 2008 to 2018. The patients age ranges between 4 to 14 years of age. AVN is classified according to Ficat radiological classifications. Stage 1, 2A, and 2B are operated. Stage 3 and 4 hips were operated if the other hip is stage 1 or 2. We found a significant improvement of the operated patients compared to non-operated patients. Patients were assessed in follow-up in form of pain, gait, activity and radiological grading. Core decompression is done using a percutaneous cannulated drilling that do not cross the growth plate of the head. Excellent results were found in 87%, good results in 9% and poor results in 4%. We recommend doing core decompression in all grades of AVN in sickle cell anemia children. Conclusion Core decompression in children with sickle cell anemia is a new surgical intervention. It is a simple surgical procedure that can be done by most of pediatric orthopedic surgeons. We found that core decompression is an effective method to stop and improve clinical and radiological stages of AVN of femoral head in children sickle cell anemia. We found out that core decompression in children has far much better outcome compared to adult’s core decompression.

Risk factors for postoperative avascular necrosis of the femoral head in children with developmental dysplasia of the hip.

To investigate factors associated with postoperative avascular necrosis of the femoral head (ANFH) in developmental dysplasia of the hip (DDH) patients, and if or how the associations varied among different subpopulations of age, sex and surgical method. Patients with DDH were enrolled between October 31, 2016 and July 15, 2020 in this retrospective cohort study. The average follow-up time was 21.42 ± 10.02 months. The outcome was postoperative ANFH. The main study variables were the DDH classification, Tonnis grade, International Hip Dysplasia Institute (IHDI) classification, and preoperative traction. Multivariate logistic regression was employed to assess the associations between main study variables and postoperative ANFH. Subgroup analysis was carried out based on age at reduction, sex and surgical method. Odds ratio (ORs) and 95% confidence intervals (CIs) were calculated. A total of 427 children with DDH were included, with 92 (21.55%) in the ANFH group, and 335 (78.45%) in the non-ANFH group. DDH classification was positively correlated with the risk of postoperative ANFH (OR = 4.14, 95% CI, 1.08-15.77, P = 0.038). Children with preoperative traction had a significantly decreased risk of postoperative ANFH in contrast to those without preoperative traction (OR = 0.37, 95% CI, 0.22-0.61, P < 0.001). Children aged 1-3 years who received preoperative traction has a significantly reduced risk of postoperative ANFH than those who did not receive preoperative traction (OR = 0.28, 95% CI, 0.15-0.51, P < 0.001). For children aged >3 years, positive association was found between DDH classification and the risk of postoperative ANFH (OR = 3.75, 95% CI, 1.51-9.31, P = 0.004). Girls with a more severe DDH type had a significantly higher risk of postoperative ANFH (OR = 3.80, 95% CI, 1.80-8.02, P < 0.001). Receiving preoperative traction was associated with a significantly decreased risk of postoperative ANFH in girls (OR = 0.37, 95% CI, 0.22-0.61, P < 0.001). For children undergoing open reduction, DDH classification was positively associated with the risk of postoperative ANFH (OR = 3.01, 95% CI, 1.65-5.50, P < 0.001), and those with preoperative traction had a lower risk of postoperative ANFH compared with those without preoperative traction (OR = 0.35, 95% CI, 0.20-0.61, P < 0.001). DDH classification and preoperative traction were associated with the risk of postoperative ANFH, and these associations varied across DDH patients with different ages, sexes and surgical methods.

Aseptic Osteonecrosis of the Femoral Head in Children Living with Sickle Cell Disease at the National Reference Center for Sickle Cell Disease of Brazzaville, Congo

Introduction: Aseptic Osteonecrosis of the Femoral Head (AOFH) is a degenerative complication of sickle cell disease. In the absence of care, it is a source of disability through painful lameness and functional impotence that it causes over time. Its data in african children are scarce. This work aimed at determining its prevalence and describing its characteristics. Methodology: It was about a descriptive study conducted over a4 years- period at the CNRDr on children suffering from homozygous sickle cell disease and presenting with ONFH. The studied variables were epidemiological, clinical and paraclinical, collected from medical records. The Postel Merle-d’Aubigné functional score was used to assess the functional status of the hips and the Arlet and Ficat classification for radiological staging. Results: The study involved 31 children (18 boys and 13 girls). The prevalence of AOFH was 2.15%. The average age was 11.51 ± 2.17 years old. Almost half were under 11 (45.16%). At diagnosis, the damage was bilateral in 10/31 cases, bringing the number of pathological hips to 41/62. Hip pain was constant and associated with lameness in 83.87% of cases. Hip function was good, fair, and poor respectively in 41.94%, 54.84% and 3.22% of cases. One child presented with two stiff hips. Radiologically, stages I and II on one hand and III and IV on the other hand of Arlet and Ficat were respectively found in 45.16% and 54.84% of cases. Conclusion: We report one of the most important series of black Africa. AOFH affects young children. The diagnosis is frequently late, made at the stage of functional impotence with joint destruction. The search for predictive factors is important to improve the prognosis of these young patients.

Total hip reconstruction after sarcoma resection in children with a free vascularized fibula without osteotomy of the bone flap: Technique description and case series

Hip joint reconstruction following intra-articular resection of the femoral head in children is a highly demanding challenge. We aimed to describe the outcomes of hip reconstruction in paediatric patients with a free fibular epiphyso-diaphyseal flap based on both anterior tibial and peroneal vessels within a radius allograft. Four patients underwent hip reconstruction following this technique between 2013 and 2020 at La Paz University Hospital (Madrid, Spain). The postoperative follow-up period ranged between 12 months and seven years. Two of the patients were diagnosed with Ewing's sarcoma and two with osteosarcoma. The median age at the time of surgery was eight years (six to nine). Three patients remained to be disease-free at the time of this study, and one died shortly after surgery, so he was excluded from the reconstruction analysis of results. No postoperative complications requiring reintervention were recorded. Imaging studies (X-ray and MRI) showed three-dimensional growth of the flap and integration of the allograft. Mean leg length discrepancy was 1.3cm (0 to 2.3). At the last follow-up visit, all patients were able to ambulate. For children following oncological resection of the femoral head, reconstruction with a vascularized epiphyso-diaphyseal fibula flap combined with radius allograft is a safe option. This procedure provides encouraging functional results and avoids the complications of previously published techniques or implants.

Study on chitosan modified indomethacin nanoparticles for relieving rain of necrosis of the femoral head in children

Osteonecrosis of the femoral head is a rare orthopedic disease in children worldwide. Due to the complexity of the disease itself, it causes great harm to children, families, and society. Among them, the morbidity of hip pain caused by osteonecrosis of the femoral head in children seriously affects the patients’ abilities to walk and self-care, thereby causing harm to the patients’ body and mind. As a result, it is crucial to explore drugs for treating pain caused by osteonecrosis of the femoral head in children. In this study, an indomethacinbased anti-inflammatory and analgesic nanodrug (CS/IND NPs) was successfully developed and used for clinical treatment of pain to validate its efficacy. The data demonstrated that in comparison with the pain score (VAS) before treatment, there was a significant difference in subsequent VAS (P &lt;0.05). The hip pain and expression of inflammatory mediators were significantly reduced. However, few adverse reactions were caused by this drug, which can significantly improve the quality of life for patients and are worth of further studies.

Comparative effectiveness of treatment modalities in severe Legg‑Calvé‑Perthes disease: Systematic review and network meta‑analysis of observational studies.

There are several treatment modalities for Legg-Calvé-Perthes disease (LCPD), self-limiting, avascular osteonecrosis of the femoral head in children. Most treatments focus on containment of the weakened femoral head, but there is no consensus on the best modality for severe LCPD. Therefore, we compared the effectiveness of all treatment modalities for severe LCPD. We searched the PubMed, Embase, and Scopus up until July 2021 for studies that investigated LCPD treatment effectiveness. A network meta-analysis was performed to examine the comparative effectiveness in terms of the ability to achieve radiographic spherical congruity of the hip joint after skeletal maturity. The risk ratio (RR) and 95% confidence interval (CI) of each treatment modality were estimated from both direct and indirect evidence. Treatment ranking was based on Surface Under the Cumulative Ranking curve (SUCRA). A total of 857 studies were identified and 34 comparative studies with 3718 affected hips comparing seven different LCPD treatment modalities were included. Compared with symptomatic treatment, combined osteotomy was the most effective modality (RR = 1.47, 95% CI 0.90 to 2.42, SUCRA = 0.8), followed by femoral varus osteotomy (RR = 1.31, 95% CI 1.06 to 1.60, SUCRA = 0.7), and Salter innominate osteotomy (RR = 1.25, 95% CI 0.95 to 1.65, SUCRA = 0.6). Combined osteotomy is the most effective procedure in terms of improving the spherical congruity of the hip joint in severe LCPD patients. However, the superiority of operative treatments seems to be limited to patients older than eightyears old.

Usefulness of Bone SPECT/CT for Predicting Avascular Necrosis of the Femoral Head in Children with Slipped Capital Femoral Epiphysis or Femoral Neck Fracture.

ObjectiveThis study aimed to investigate the usefulness of bone single-positron emission tomography/computed tomography (SPECT/CT) of the hip in predicting the later occurrence of avascular necrosis (AVN) after slipped capital femoral epiphysis (SCFE) or femoral neck fracture in pediatric patients. The quantitative parameters of SPECT/CT useful in predicting AVN were identified.Materials and MethodsTwenty-one (male:female, 10:11) consecutive patients aged < 18 years (mean age ± standard deviation [SD], 11.0 ± 2.7 years) who underwent surgery for SCFE or femoral neck fracture and postoperative bone SPECT/CT were included. The maximum standardized uptake value (SUV), mean SUV, and minimum SUV of the femoral head were measured. The ratios of the maximum SUV, mean SUV, and minimum SUV of the affected femoral head to the contralateral side were determined. Patients were followed up for > 1 year after the surgery. The SPECT/CT parameters were compared between patients who developed AVN and those who did not. The accuracy of SPECT/CT parameters for predicting AVN was assessed.ResultsSix patients developed AVN. There was a significant difference in the ratio of the mean SUV among patients who developed AVN (mean ± SD, 0.8 ± 0.3) and those who did not (1.1 ± 0.2, p = 0.018). However, there were no significant differences in the ratios of the maximum and minimum SUV between the groups (all p = 0.205). For the maximum, mean, and minimum SUVs, no significant differences were observed between the groups (p = 0.519, 0.733, and 0.470, respectively). The cutoff mean SUV ratio of 0.87 yielded a 66.7% sensitivity and 93.2% specificity for predicting AVN.ConclusionQuantitative bone SPECT/CT is useful for evaluating femoral head viability in pediatric patients with SCFE or femoral neck fractures. Clinicians should consider the high possibility of later AVN development in patients with a decreased mean SUV ratio.

The Effect of Glucocorticoid therapy on Bone Mineral Density in Children and Adolescents with Congenital Adrenal Hyperplasia

Background: Congenital adrenal hyperplasia (CAH) is a group of autosomal recessive diseases caused by a deficiency in adrenal enzymes that lead to changes in cortisol and aldosterone levels. Objective: This study aimed to assess the bone mineral density of the spine and femoral head in children and adolescents aged 5 and 20 years, suffering from different types of congenital adrenal hyperplasia and treated with corticosteroids and to study the associated factors. Materials and method: We studies 44 patients, 26 girls and 18 boys, who were treated with corticosteroids with a physiological dose of 15-20 mg/m2 since infancy. A questionnaire was completed by patients and their parents admitted to the Endocrinology Clinic of Imam Reza Hospital of Mashhad. The patients' bone density was then measured, and the association with different factors, such as age, gender, height, weight, type of CAH, type and duration of receiving corticosteroids, the 17-hydroxyprogesterone level, bone activity markers, vitamin D level, and puberty stage, was analyzed, using SPSS software. Result: No significant correlation between the bone density level and variables such as the duration and dose of corticosteroid consumption, age, sex, time of diagnosis, 17-hydroxyprogesterone level, calcium, and phosphorus, was found. Other variables such as height, weight, puberty stage, and vitamin D levels were found to play a significant role in determining the bone density level.Conclusion: It is highly recommended to consider the side effects and complications when starting treatment with corticosteroids in patients with CAH. Bone densitometry should regularly be done, osteoporosis prophylaxis should be considered using weight-bearing exercises and calcium and vitamin D supplements, and the level of vitamin D should be monitored.

Feasibility of Magnetic Resonance Angiography in Patients With Legg-Calvé-Perthes Disease.

The etiology of Legg-Calvé-Perthes disease (LCPD) remains unknown; however, interruption of medial circumflex femoral artery (MCFA) supply to the femoral head is the key pathogenic factor. The main purpose of this study is to determine the feasibility of using magnetic resonance angiography (MRA) to evaluate the course of the MCFA in the normal and affected hips of patients with unilateral LCPD. We analyzed 24 patients with unilateral LCPD using a time-resolved imaging of contrast kinetics magnetic resonance angiography (TRICKS-MRA). The course of the MCFA was divided into 4 segments in the coronal plane and in 3 segments in the axial plane, based on its location with respect to the femoral neck. The visibility of each segment was studied in the normal and affected sides. The segments were defined as not visible when no contrast was seen within the vessel lumen or visible when the lumen was partially or completely visualized with contrast. The statistical analysis was done using the χ2 test. TRICKS-MRA provided well-defined images of the first 2 segments of the MCFA on both the normal and affected sides of patients with LCPD (P=1). In half of the patients, the third segment was also visible using TRICKS-MRA on both sides (P=1). The fourth segment of the MCFA, which was the ascending lateral epiphyseal segment, was not visible on either side (P=0.49). No significant difference was found between the normal and affected hips in terms of visibility of the 4 segments of the MCFA using TRICKS-MRA. Anastomosis of the MCFA with the inferior gluteal artery was found in 3 hips (2 hips with LCPD and 1 normal hip). TRICKS-MRA provides well-defined images of the arterial supply to the proximal femoral epiphysis in children with LCPD, presenting a noninvasive and radiation-free alternative to conventional angiography. However, the TRICKS-MRA method used did not allow visualization of the ascending lateral epiphyseal segment of MCFA in the affected and the contralateral normal side. We believe that further advancement of this noninvasive imaging technique may open new opportunities for research aimed at evaluating the vascular supply of the femoral head in children. Level IV-case-control study.

Risk Factors for Avascular Necrosis of the Femoral Head in Pediatric Femoral Neck Fractures

IntroductionA neck of femur fracture is a rare injury in the pediatric population and is of foremost importance, as it is associated with a high rate of complications. It usually occurs due to high-velocity trauma or a fall from a height. There is a scarcity of data on risk factors and their role in the prognostication of avascular necrosis. The purpose of the study was to retrospectively analyze the association of various risk factors with avascular necrosis (AVN) of the femoral head in patients with a neck of femur fracture in the pediatric age group.Material and methodsThe study included 21 (13 males and 8 females) pediatric patients with a neck of femur fracture treated at a university-level hospital. The patients were followed for a minimum of one year and the clinico-radiological outcome was analyzed using Ratliff criteria. The association of AVN with age, gender, side, fracture type, and injury with treatment delay, type of reduction, and type of internal fixation used was studied.ResultsThe mean age of the treated patients was 11 (±3.178) years (range=5-16 years). Avascular necrosis was seen in four patients and coxa vara occurred in two of them. A statistically significant association was seen between the Delbet fracture type and avascular necrosis, and three out of four cases of AVN were a Type I fracture (p-value=0.006). Three out of six patients having concomitant skeletal or other organ injuries developed AVN (p-value=0.022). The rate of AVN was higher in patients who were managed after 48 hours of initial injury but no statistically significant correlation was found (p-value=0.314). No statistically significant association with AVN was found between gender, age, type of reduction (closed/open), or the implant used (cannulated screws/k-wires).ConclusionsMultiple independent factors may have a role in the development of AVN of the femoral head in children. Prognostication should not be based on a single factor. Statistically significant results in this study have shown that the type of fracture and concomitant skeletal or other organ injuries are important risk factors and should be kept in mind. All independent risk factors must be noted and should be considered while prognosticating the outcome of a child with a neck of femur fracture.

Outcomes of Osteonecrosis of the Femoral Head in Children and Adolescents with Sickle Cell Disease (SCD)

Outcomes of Osteonecrosis of the Femoral Head in Children and Adolescents with Sickle Cell Disease (SCD)

Outcomes of Osteonecrosis of the Femoral Head in Children and Adolescents with Sickle Cell Disease (SCD)

Purpose: Osteonecrosis of the femoral head (ONFH) is a common complication of SCD. We set out to describe clinical and radiographic outcomes of SCD patients ≤21 years with ONFH, who were treated with (1) core decompression (CD) or (2) CD plus bone marrow aspirate concentrate (BMAC) injection, (3) total hip arthroplasty (THA) or (4) observation alone. Methods: 114 hips in 73 SCD patients, 42% female, mean age 16.4 years (range, 5.7-21.9 years) with an ONFH diagnosis between 2006 and 2018 were …

Research progress in animal model of Perthes disease

Perthes disease is the ischemic necrosis of femoral head in children.It was also called osteochondrositis of femoral head in children, aseptic necrosis of femoral head, avascular necrosis of femoral head, etc., which reflected people′s understanding of this disease in different periods.The disease has a certain tendency of self-healing.The femoral head deformity left behind by some of the children may lead to the hip joint weight-bearing and mobility dysfunction, or even disability and deformity, and the clinical effect is worrying.Despite more than 100 years of research, the etiology and pathogenesis are still unclear, mainly due to the lack of ideal animal models for the corresponding research.Over the years, many efforts and attempts have been made by scholars.At present, the recent studies on animal model of Perthes disease have been reviewed in order to provide references for children′s orthopaedic doctors to further understand this disease. Key words: Perthes disease; Animal model; Etiology

Risk factors for the development of avascular necrosis after femoral neck fractures in children: a review of 239 cases.

The aim of this study was to clarify the factors that predict the development of avascular necrosis (AVN) of the femoral head in children with a fracture of the femoral neck. We retrospectively reviewed 239 children with a mean age of 10.0 years (sd 3.9) who underwent surgical treatment for a femoral neck fracture. Risk factors were recorded, including age, sex, laterality, mechanism of injury, initial displacement, the type of fracture, the time to reduction, and the method and quality of reduction. AVN of the femoral head was assessed on radiographs. Logistic regression analysis was used to evaluate the independent risk factors for AVN. Chi-squared tests and Student's t-tests were used for subgroup analyses to determine the risk factors for AVN. We found that age (p = 0.006) and initial displacement (p = 0.001) were significant independent risk factors. Receiver operating characteristic (ROC) curve analysis indicated that 12 years of age was the cut-off for increasing the rate of AVN. Severe initial displacement (p = 0.021) and poor quality of reduction (p = 0.022) significantly increased the rate of AVN in patients aged 12 years or greater, while in those aged less than 12 years, the rate of AVN significantly increased only with initial displacement (p = 0.048). A poor reduction significantly increased the rate of AVN in patients treated by closed reduction (p = 0.026); screw and plate fixation was preferable to cannulated screw or Kirschner wire (K-wire) fixation for decreasing the rate of AVN in patients treated by open reduction (p = 0.034). The rate of AVN increases with age, especially in patients aged 12 years or greater, and with the severity of displacement. In patients treated by closed reduction, anatomical reduction helps to decrease the rate of AVN, while in those treated by open reduction, screw and plate fixation was preferable to fixation using cannulated screws or K-wires. Cite this article: Bone Joint J 2019;101-B:1160-1167.

Risk of avascular necrosis of the femoral head in children with sickle cell disease on hydroxyurea: MRI evaluation.

There are conflicting reports on the role of hydroxyurea (HU) in the pathogenesis of avascular necrosis of the femoral head (AVNFH) in patients with sickle cell disease (SCD). The present study is a prospective cohort study of Kuwaiti children with SCD who were treated with HU. They had magnetic resonance imaging of the hips before starting HU and at regular intervals during a follow-up period, ranging from 1 to 15 years. There were 40 patients (18 SS, 19 Sβ0-thalassemia, and three SD genotypes), aged 6-20 years. Pre-HU, 11 (27.5%) had varying grades of AVNFH, while post HU, the prevalence was 32.5%. Two patients developed new lesions during the study, while five (45.5%) that had lesions pre-HU remained static, another five (45.5%) progressed, and one (9%) improved radiologically. The older patients who had been on HU the longest were more likely to deteriorate. The only hematological parameter that was consistently associated with AVNFH was the reticulocyte count. The frequency and rate of progression of AVNFH in this study is much less than that previously reported for our patients not treated with HU. There is no evidence that HU therapy is a risk factor for AVNFH. It may, in fact, prevent new lesions and deter the progression of existing AVNFH.

Is there a correlation between Reimers’ hip migration percentage and stiffness of hip muscles measured by shear wave elastography in children with cerebral palsy?

The Reimers’ hip migration percentage (MP) is commonly used to examine the amount of lateral displacement of the femoral head in children with cerebral palsy (CP). Abnormal forces of the hip flexor and adductor muscles are proposed as the contributing factors of hip dislocation in children with CP. Shear wave elastography (SWE) is an ultrasound based technique which provides a quantitative measurement of the tissue stiffness. The aim of this study was to assess the correlation between the MP and the stiffness of the hip muscles. This prospective study included 50 hips of 25 children with spastic CP. All muscles were evaluated in longitudinal plane by SWE with a linear transducer that enables scanning with a frequency ranging of 9 − 4 MHz. The stiffness of the gluteus medius and maximus, adductor magnus and iliopsoas muscles was measured by SWE. The MP was measured on anteroposterior radiographs. The correlation between the Reimer's MP and the stiffness of hip flexors and adductors were analyzed. The correlations among the stiffness of the hip flexor-extensor and adductor-abductor muscle groups were also assessed. There is a moderate positive correlation between MP and the stiffness of hip flexor muscles ( r = 0.70, P < 0.05). There is a moderate positive correlation between MP and the stiffness of hip adductor muscles ( r = 0.71, P < 0.05). The correlation between the stiffness of flexor and extensors is weak ( r = 0.10, P ≥0.05). There is a weak correlation between the stiffness of abductor and adductor muscles ( r = 0.32, P ≥0.05). We suggest that increased flexor and adductor muscle stiffness would be a potential high risk factor of hip dislocation in children with CP. Measuring muscle stiffness may provide helpful information during follow-up of these patients.

Is there a correlation between Reimers’ hip migration percentage and stiffness of hip muscles measured by shear wave elastography in children with cerebral palsy?

The Reimers’ hip migration percentage (MP) is commonly used to examine the amount of lateral displacement of the femoral head in children with cerebral palsy (CP). Abnormal forces of the hip flexor and adductor muscles are proposed as the contributing factors of hip dislocation in children with CP. Shear wave elastography (SWE) is an ultrasound based technique which provides a quantitative measurement of the tissue stiffness. The aim of this study was to assess the correlation between the MP and the stiffness of the hip muscles. This prospective study included 50 hips of 25 children with spastic CP. All muscles were evaluated in longitudinal plane by SWE with a linear transducer that enables scanning with a frequency ranging of 9 − 4 MHz. The stiffness of the gluteus medius and maximus, adductor magnus and iliopsoas muscles was measured by SWE. The MP was measured on anteroposterior radiographs. The correlation between the Reimer's MP and the stiffness of hip flexors and adductors were analyzed. The correlations among the stiffness of the hip flexor-extensor and adductor-abductor muscle groups were also assessed. There is a moderate positive correlation between MP and the stiffness of hip flexor muscles ( r = 0.70, P < 0.05). There is a moderate positive correlation between MP and the stiffness of hip adductor muscles ( r = 0.71, P < 0.05). The correlation between the stiffness of flexor and extensors is weak ( r = 0.10, P ≥0.05). There is a weak correlation between the stiffness of abductor and adductor muscles ( r = 0.32, P ≥0.05). We suggest that increased flexor and adductor muscle stiffness would be a potential high risk factor of hip dislocation in children with CP. Measuring muscle stiffness may provide helpful information during follow-up of these patients.