Perthes disease: evaluation and management

Proximal femoral varus osteotomy for Legg-Calvé-Perthes disease: Do age and lateral pillar classifications influence short-to-mid-term clinical and radiological outcomes?

INTRODUCTION

Proximal femoral varus osteotomy (FVO) is one of the most used treatment methods with acceptable outcomes for Legg-Calvé-Perthes disease (LCPD). We aimed to investigate the influence of age at disease onset and the Lateral Pillar classification on clinical and radiological outcomes of FVO surgery LCPD patients between 6-12years of age.

HYPOTHESIS

Proximal FVO surgery in the early fragmentation phase of LCPD patients led to acceptable clinical and radiographic outcomes in a 3-year follow-up, regardless of preoperative age and Herring type.

MATERIAL AND METHODS

Fifty patients with LCPD (Herring groups B, B/C, and C) who underwent FVO were retrospectively reviewed. We evaluated radiological [center-edge angle, extrusion index, epiphyseal index, acetabular index, articulo-trochanteric distance (ATD)] and clinical [hip abduction range of motion (ROM), Trendelenburg sign, pain, and Harris hip score (HHS)] outcomes with a follow-up of 37.3±10.5months (range: 24-180months). Finally, the overall treatment outcome was assessed using the Stulberg classification.

RESULTS

The ROC curve analysis did not reveal any significant relationship between age and clinical or radiological outcomes, and there was no predictable age cut-off for surgical outcomes (p=0.13). No significant difference was found in Stulberg classification at the follow-up between patients with type B, B/C, and C of the lateral pillar (p>0.05).

DISCUSSION

Our results demonstrated that open-wedge proximal FVO surgery in the early fragmentation phase of LCPD patients led to acceptable clinical and radiographic outcomes in a 3-year follow-up. Each sample of our study was very small and a lot of variables were measured, making this result not adequately strong enough to draw a robust conclusion. However, FVO surgery remains a possible suggestion for patients in the early fragmentation phase, and age and lateral pillar type may not be limiting factors.

LEVEL OF EVIDENCE

IV; therapeutic retrospective cohort.

Association between Polymorphism eNOS4, tPA, Factor V Leiden, Prothrombin, and Methylenetetrahydrofolate Reductase and the Occurrence of Legg-Calvé-Perthes Disease

BACKGROUND

Legg-Calvé-Perthes (LCPD) disease is a complex condition affecting the femoral head's epiphysis in children. It occurs with a prevalence ranging from 0.4 to 29.0 cases per 100,000 children under the age of 15. It involves various factors, including genes associated with coagulation and fibrinolysis, pro-inflammatory factors, and vasoactive substances.

METHODS

We investigated the relationship between genetic mutations associated with coagulation and vascular disorders and the occurrence of LCPD in Polish patients. We performed a study involving 25 patients with LCPD and 100 healthy controls. All subjects were genotyped for eNOS4, Factor V Leiden, prothrombin, tPA25, and MTHFR polymorphism.

RESULTS

The analysis revealed that the frequencies of eNOS4 genotypes were significantly different in LCPD patients than in the control group (p = 0.018). The frequencies of 4a allele were significantly higher in patients with LCPD than in the healthy population (26% vs. 9%, p = 0.0012). There were no significant differences in genotype and allele frequencies for Factor V Leiden, prothrombin tPA 25, and MTHFR gene polymorphisms between patients with LCPD and the controls.

CONCLUSIONS

Genotype and allele frequencies of eNOS4 were significantly higher in patients with LCPD. These findings suggest a potential association between the eNOS gene polymorphism and an increased risk of developing LCPD.

Case study of Legg-Calvé-Perthes disease observed in Radom (Poland, 18th–19th century) with literature review

The aim of this study is to present the pathological lesions observed in a skeleton (male, about 35–38 years old) from Radom (Poland), dated to the 18th–19th century. Bone changes were observed in both femurs and both pelvic bones. The head of the femur is enlarged and deformed, described as “mushroom-shaped”, with areas of smooth cortex and cavities, or possible cystic residues. The neck of femur is short and thick. The bone shaft and distal epiphysis do not show any changes. The changes were also observed in both acetabularies of the hip joint (marginal bone formation, subchondral bone remodelling). Radiographic images show bilateral necrosis of the femoral head. There is a significant sclerotization of the femoral head, with a discrete visible crescent sign. These macroscopic and radiological changes match the symptoms associated with Legg-Calvé-Perthes disease. This is the first case of the disease described in bioarchaeological materials from Poland.

Prothrombin Time and Coagulation Factor IX as Hemostatic Risk Markers for Legg- Calvé-Perthes Disease

BACKGROUND

Legg-Calvé-Perthes disease (LCPD) is a pediatric disorder that occurs due to the avascular necrosis of the femoral head and affects the range of motion of the hip in various degrees. Its etiology is still unknown, although it has been associated with coagulation abnormalities, however, the lack of reproducibility in the results in various studies has created a controversy as to whether hemostasis disorders are related to LCPD. On the other hand, there is little information on laboratory studies that could facilitate the diagnosis and treatment of LCPD.

METHODS

Blood and plasma samples were tested from 25 patients with LCPD and 50 healthy controls, matched by sex and age. Cellular markers were evaluated through complete blood count, as well as coagulation times, coagulation factors activity, antithrombotic proteins, and homocysteine concentration.

RESULTS

After assessing activity value frequencies in each group, the results showed more significant activity in some of the biological risk markers of thrombophilia, presenting a substantial difference in prothrombin time↘, FV↗, FVIII↗, FIX↗, and Hcy↗. These values imply that there may be hypercoagulable states in patients, which can cause thrombotic events.

CONCLUSIONS

Diminished prothrombin time and increase in FV activity, FVIII, FIX, and Hcy concentration support the hypothesis that microthrombi formation in small-caliber vessels could be causing avascularity and femoral necrosis, which are traits of LCPD. In addition, based on our results, we believe that the laboratory studies carried out are very useful in the diagnosis and treatment of LCPD.

Outcomes in Pediatric Hip FAI Surgery: a Scoping Review

PURPOSE OF REVIEW

Femoracetabular impingement (FAI) is a common source of hip pain in children and adolescents. While nonoperative therapies and open surgical procedures can be effective, hip arthroscopy is a minimally invasive treatment option with substantial benefit. The purpose of this paper is to evaluate the current role of hip arthroscopy in treating FAI within the pediatric population. This article examines its efficacy through a review of hip arthroscopy outcomes in the contemporary orthopaedic literature.

RECENT FINDINGS

Morphologic changes in the acetabulum and proximal femur seen in FAI can be attributed to a multitude of etiologies-including idiopathic FAI, Legg-Calve-Perthes, and slipped capital femoral epiphysis. In general, arthroscopic treatment of FAI secondary to these conditions leads to statistically significant improvements in pain and patient-reported outcomes in the short and long term. In the pediatric athlete, repetitive stress on the hip perpetuates FAI and can drastically hinder performance. Hip arthroscopy allows for a high rate of return to sport with minimal morbidity in this population. Overall, pediatric hip arthroscopy is effective in treating FAI secondary to a wide variety of conditions. Despite its clinical benefits, patients and their families should be counseled regarding alternative treatments, potential complications, and return to play.

T1ρ and T2 MRI show hip cartilage damage in adolescents with healed Legg-Calvé-Perthes disease

Legg-Calvé-Perthes disease (LCPD) is a juvenile hip disorder associated with residual femoral head deformity, cartilage degeneration and a high risk of early onset hip osteoarthritis. Assessing management of LCPD in the healed phase requires an understanding of when and where hip cartilage damage happens. While it has been shown that cartilage is degenerated in healed LCPD hips in adults, it is not clear when this degeneration begins. Our research question was: Are the MR markers of cartilage degeneration T1ρ and T2 increased in healed LCPD hips in adolescents? Twelve adolescents [10-17 years old (mean 14); 3 female 9 male] with healed LCPD (Stulberg 2-5; 8 unilateral and 4 bilateral) and 15 age- and sex-matched controls were imaged in a 3T MRI using a T1ρ and a T2 sequence. We applied a mixed-effects model adjusted for age and nested by subject to determine the effect of Stulberg grade on overall and regional mean T1ρ and T2 values. T1ρ was significantly higher overall and in the medial region of Stulberg ≥3 hips, and in the medial region of Stulberg 2 hips than in the control group. T2 was significantly higher in the medial region of Stulberg ≥3 hips than in the control group. Our results suggest that cartilage damage in LCPD has begun by adolescence and that T1ρ can detect early changes in cartilage associated with LCPD.

Co-occurrence of Blount's disease and Legg-Calvé-Perthes disease: is obesity a factor?

Legg-Calvé-Perthes disease (LCPD) and Blount's disease share a similar presenting age in addition to similar symptoms such as limp or knee pain. A little overlap is mentioned about both diseases. We sought to present cases of children having both conditions to discuss the implications of this co-occurrence on diagnosis and management. After institutional review board approval, we retrospectively reviewed records of four children who developed both Blount's disease and LCPD. Patient details and outcomes were analyzed. Radiographs were evaluated for the lateral pillar classification, Stulberg classification, tibial metaphyseal-diaphyseal angle and tibiofemoral angle. Two of the cases were initially diagnosed with Blount's disease and subsequently developed Perthes, one case presented initially with both disorders and the final case had Perthes followed by Blount's. Three children were obese and one was overweight. The common symptom to all patients was an abnormal gait, which was painless in two children and painful in two. Blount's disease required surgery in three children. Radiographs showed Lateral Pillar B, B/C border and C hips, and the final Stulberg was stage II (n = 2) or stage IV (n = 2). Obesity is associated with Blount's disease and LCPD, so obese children can be at an increased risk of developing both disorders. Therefore, a child with Blount's disease who has persistent, recurrent or worsening symptoms such as gait disturbance or thigh or knee pain might benefit from a careful physical exam of the hips to prevent a delayed or even missed LCPD diagnosis.

Contrast-enhanced ultrasound for musculoskeletal indications in children

The increasing use of contrast-enhanced ultrasound (CEUS) has opened exciting new frontiers for musculoskeletal applications in adults and children. The most common musculoskeletal-related CEUS applications in adults are for detecting inflammatory joint diseases, imaging skeletal muscles and tendon perfusion, imaging postoperative viability of osseous and osseocutaneous tissue flaps, and evaluating the malignant potential of soft-tissue masses. Pediatric musculoskeletal-related CEUS has been applied for imaging juvenile idiopathic arthritis and Legg-Calvé-Perthes disease and for evaluating femoral head perfusion following surgical hip reduction in children with developmental hip dysplasia. CEUS can improve visualization of the capillary network in superficial and deep tissues and also in states of slow- or low-volume blood flow. In addition, measurements of blood flow imaging parameters performed by quantitative CEUS are valuable when monitoring the outcome of treatment interventions. In this review article we present current experience regarding a wide range of CEUS applications in musculoskeletal conditions in adults and children, with emphasis on the latter, and discuss imaging techniques and CEUS findings in musculoskeletal applications.

Early to medium-term outcomes of uncemented ceramic-bearing total hip arthroplasty in teenagers for paediatric hip conditions

AIMS

Despite advances in the treatment of paediatric hip disease, adolescent and young adult patients can develop early onset end-stage osteoarthritis. The aims of this study were to address the indications and medium-term outcomes for total hip arthroplasty (THA) with ceramic bearings for teenage patients.

METHODS

Surgery was performed by a single surgeon working in the paediatric orthopaedic unit of a tertiary referral hospital. Databases were interrogated from 2003 to 2017 for all teenage patients undergoing THA with a minimum 2.3 year follow-up. Data capture included patient demographics, the underlying hip pathology, number of previous surgeries, and THA prostheses used. Institutional ethical approval was granted to contact patients for prospective clinical outcomes and obtain up-to-date radiographs. In total, 60 primary hips were implanted in 51 patients (35 female, 16 male) with nine bilateral cases. The mean age was 16.7 years (12 to 19) and mean follow-up was 9.3 years (2.3 to 16.8).

RESULTS

The most common indication for teenage hip arthroplasty was avascular necrosis secondary to slipped upper femoral epiphysis (31%; n = 16). Overall, 64% of patients (n = 33) had undergone multiple previous operations. The survival at follow-up was 97%; two patients required revision for aseptic loosening (one femoral stem, one acetabular component). Both patients had fused hips noted at the time of arthroplasty. A further two patients had radiolucent lines but were asymptomatic. At latest follow-up the mean Oxford Hip Score was 44 (31 to 48) and a Visual Analogue Scale measurement of 1.5, indicating satisfactory function.

CONCLUSION

Operating on this cohort can be complicated by multiple previous surgeries and distorted anatomy, which in some cases require custom-made prostheses. We have demonstrated a good outcome with low revision rate in this complex group of patients. Cite this article: Bone Joint J 2020;102-B(11):1491-1496.

Range of abduction in patients with Legg-Calvé-Perthes disease - a nationwide register-based cohort study

BACKGROUND

Range of abduction often decreases during Legg-Calvé-Perthes Disease (LCPD) disease. However, a good range of abduction is required during the course of LCPD, especially when containment surgery should be performed. This study aimed to investigate how many patients registered in the Swedish Pediatric Orthopedic Quality register (SPOQ) with LCPD had reduced range of abduction at diagnosis in relation to sex or age at diagnosis or severity of disease (lateral pillar class at the time at diagnosis), if physiotherapy (PT) was prescribed and has a beneficial impact in maintaining (or increasing) abduction and if the range of abduction at diagnosis before fragmentation stage is predictive for the lateral pillar classification at fragmentation stage.

METHODS

The national Swedish Pediatric Orthopedic Quality Register (SPOQ), established in 2015, is used to identify patients with LCPD. The patients are registered at three time points: at diagnosis, at potential surgery and 2 years after diagnosis. Range of abduction and information on PT are required to register at all registration sessions. One hundred ninety-nine hips from 192 children were registered in the SPOQ.

RESULTS

Of all hips, the mean range of abduction at diagnosis was 39 degrees (range 0 to 90). One hundred twenty-six patients (63%) either received instructions for PT or were referred to a physiotherapist; two patients were treated additionally with an abduction brace. There was a trend that patients who received PT, compared to patients without PT, either maintained or increased their range of abduction at the 2-year follow-up. Older age at diagnosis correlated with decreased range of abduction at the 2-year follow-up (Estimate [Est]: - 3.1, 95% confidence interval [CI]: - 4.4 to - 1.7). The degree of abduction at diagnosis before fragmentation stage correlated with the lateral pillar group at the fragmentation stage (Est: -5.3, 95% CI: - 10.0 to - 1.1).

CONCLUSION

In all, 63% of the children with LCPD in SPOQ received either written instructions or were referred to PT or both. PT seems to have a favorable impact for maintaining the range of abduction in children with LCPD. Children with a lower range of abduction at diagnosis (before the fragmentation stage) developed a higher degree of lateral pillar involvement as measured by the lateral pillar classification.

Assessing the role of hip arthrography in the treatment decision making for children with Legg-Calvé-Perthes disease

OBJECTIVE

The aim of this study was to determine the role of hip arthrography in the treatment decision making for children with Legg-Calvé-Perthes disease (LCPD).

METHODS

A total of 47 consecutive children with LCPD (42 boys, 5 girls; mean age=7.5 years; range=6-10 years) who underwent operative treatment were included in the study. The patient demographics, physical examination findings (pain and hip range of motion [ROM]), standard anteroposterior and Löwenstein lateral hip radiographs, and hip arthrography data were retrospectively collected. The arthrographies were performed immediately before the surgery under general anesthesia. The patients were staged according to the Catterall and Herring classifications and examined in terms of head-at-risk signs before the study. Four sets of patient files were established based on the aforementioned data, with each child in a randomized and blinded order. Ten consultant pediatric orthopedic surgeons randomly assessed the patient files on 4 separate occasions (Set 1 vs Set 2 and Set 3 vs Set 4), with a minimum time interval of 4 weeks. In the first and second sets, the demographic and clinical information, including the age, gender, hip ROM, and hip radiographs, were presented. In the third and fourth sets, hip arthrography was presented in addition to the data from Set 1 and Set 2. The observers were instructed to choose the best treatment options. The percent agreement (PA) and Gwet's AC1 statistics were used to establish a relative level of agreement among the observers.

RESULTS

The mean intra-observer reliabilities ranged from fair to moderate after adding the hip arthrography data (Gwet's AC1 = 0.36 for Set 1 vs Set 2 and 0.42 for Set 3 vs Set 4). The mean PA was 56.6% (range = 29.8% to 78.7%) with a Gwet's AC1 value of 0.51 (range: 0.21 to 0.77) between Set 1 and Set 3 (moderate intra-observer reliability). The decision for the treatment strategy was changed in 43.4% of the patients. For inter-observer reliability, Gwet's AC1 was computed as 0.48 (moderate reliability). The correlation between the intra-observer reliability and stage progression was not significant (p>0.05) for any of the subgroups. Thus, there is a negative correlation with the disease progression.

CONCLUSION

Hip arthrography seems to have a significant role in the treatment decision making for children with LCPD, especially in the advanced stages of the disease.

LEVEL OF EVIDENCE

Level IV, Therapeutic study.

The Effect of Clinical Knowledge and Surgical Experience on Treatment Choice in Legg-Calve-Perthes Disease: Intra-observer and Inter-observer Reliability Study

AIM

The aim of this study was to evaluate standardized hip radiographs, arthographs, demographic characteristics, physical examination findings, and their effects on treatment choices in leg-calve-perthes disease (LCPD). Intraobserver and interobserver realibility between orthopaedic residents, orthopaedic surgeons, and paediatric orthopaedic surgeons were also investigated.

MATERIALS AND METHODS

47 LCPD patients were included this cross-sectional study. Six separate presentations including different variabilities (clinical findings, standard radiographs, and arthrographs) were evaluated by three different groups (residents, surgeons, paediatric orthopaedic surgeons) and were sent to the observers every other month by hiding patients' personal information. Seven different treatment modalities were introduced for the best treatment modality. Intraobserver and interobserver reliability in these three groups were examined. Percentage aggreement (PA) and intraclass correlation coefficients (ICC) tests were used for this purpose.

RESULTS

Treatment PA rates between presentations were 29.5-53.6% in residents, 38.3-60.4% in surgeons, and 39.1-59.8% in pediatric orthopaedic surgeons. Conservative methods were mostly preferred as treatment modality in all groups; followed by proximal femoral osteotomies. Pediatric orthopaedic surgeons preferred safe dislocation and femur head and/or neck reconstruction surgery 5-18 times more than residents and orthopaedic surgeons. Intraobserver reliability of treatment modalities was higher among the paediatric orthopaedic surgeons; the results were fair-good (0.483-0.763). Among residents and orthopaedic surgeons, ICC values were poor to good, respectively (- 0.080 to 0.636 and 0.263-0.643). Interobserver reliability among three groups was meanly good.

CONCLUSION

As surgical experience increases, both the compliance rates of the treatment modalities and the intra- and inter-group reliability are increased. Knowledge of the demographic data and clinical findings of patients besides hip radiographs or arthrographs increase treatment compliance in paediatric orthopaedic surgeons, however, cause changes in treatment modalities in residents. As surgical experience increases, more difficult surgeries such as safe dislocation and femoral head/neck reconstruction are preferred.

Isolated Trochanteric Descent and Greater Trochanteric Apophyseodesis Are Not Effective in the Treatment of Post-Perthes Deformity

BACKGROUND

Greater trochanteric apophyseodesis and isolated trochanteric descent seek to prevent abductor weakness in patients with a hip deformity because of Legg-Calvé-Perthes disease; however, no studies have evaluated radiographic findings or abductor strength in children treated with these procedures.

QUESTIONS/PURPOSES

(1) Do children with Waldenström Stage III Legg-Calvé-Perthes disease treated with either isolated greater trochanteric descent or isolated greater trochanteric apophyseodesis achieve improved radiographic findings (Stulberg classification or neck-shaft angle) compared with those who underwent no surgical treatment? (2) Do children treated with one of those procedures achieve greater abductor strength than those who did not have surgery?

METHODS

Between 2006 and 2010, we treated 89 children with Waldenström Type III Legg-Calvé-Perthes disease (reossification). Of these, 27.9% (12 patients) underwent greater trochanteric descent, 25.6% (11 patients) underwent greater trochanteric apophyseodesis, and 46.5% (20 patients) did not have surgery. During that time, the decision to perform either apophyseodesis or trochanteric descent was made by the surgeon based on the subjective appearance of remaining growth from the greater trochanter. Nonsurgical management was chosen by the parents of the patients after the risks and benefits of surgery were discussed. During greater trochanteric descent, the greater trochanter was osteotomized and fixed distally with two 7.0-mm screws. During greater trochanteric apophyseodesis, the physis was identified fluoroscopically, and the lateral half of the growth plate was drilled. Nonoperative treatment involved serial clinical and radiographic evaluations every 3 to 6 months. All children in all groups were available for follow-up at a minimum of 6 years. The median follow-up durations for children undergoing greater trochanteric descent, greater trochanteric apophyseodesis, and control cohorts were 6.6 years (range 6.0-8.2 years), 6.5 years (range 6.1-9.2 years), and 7.4 years (range 6.0-9.1 years), respectively. On presentation, each patient's affected hip was classified according to the Stulberg classification by the operating surgeon and an orthopaedic surgeon not involved in the child's care. The neck-shaft angle was measured for each patient before surgery and at the final follow-up examination. Abductor strength was assessed by a pediatric orthopaedic fellow and a physical therapist with the patient in the lateral decubitus position. Each patient was given a muscle strength score on a scale of 0 to 10 points, per a modification of the Medical Research Council scale to allow for a narrower range. We had 80% power to detect an 8° difference in the neck-shaft angle between the greater trochanteric apophyseodesis and nonoperative management cohorts. A sample size of 6.8 patients per cohort would be necessary to detect the above endpoint.

RESULTS

With the numbers available, we found no differences among the groups in the proportion of patients with Stulberg Class 2 femoral heads (two of 12 patients in the isolated trochanteric descent group, three of 11 in the isolated trochanteric apophyseodesis group, and two of 20 who did not undergo surgery; p = 0.46). Likewise, there were no differences among the three groups in terms of the neck-shaft angle at a minimum of 6 years of follow-up (122° ± 6°, 119° ± 7°, and 126° ± 8° in the isolated trochanteric descent, isolated trochanteric apophyseodesis, and nonoperative groups, respectively). There were no differences among the groups in term of the median abductor strength test result: seven of 10 (range 6-8), six of 10 (range 6-8), and six of 10 (range 6-10; p = 0.34).

CONCLUSION

Because neither isolated greater trochanteric descent nor greater trochanteric apophyseodesis alone had an effect on hip morphology or abductor strength in children with sequellae of Legg-Calvé-Perthes disease, we conclude these types of extraarticular surgery are ineffective. Therefore, we no longer perform isolated trochanteric descent or apophyseodesis.

LEVEL OF EVIDENCE

Level III, therapeutic study.

A not to be missed cause in a child with atraumatic limp

Children with musculoskeletal symptoms are commonly seen by general practitioners (GPs). Those that present with atraumatic limp pose a particular diagnostic challenge. Although uncommon, Perthes disease (PD) is an important cause of atraumatic limp in children and may result in debilitating consequences if missed. We put forward a case of delayed diagnosis of PD in a child, thus highlighting the need for a greater index of suspicion among GPs in approaching any child with a limp.

Developmental Dysplasia of the Hip with Concurrent Legg-Calvé-Perthes Disease in the Contralateral Hip

Developmental dysplasia of the hip (DDH) is a common hip disorder in pediatrics; about one in 100 newborns has it due to dysplasia and one to two per 1000 have it due to dislocation. Some factors are responsible for the disease, and breech presentation has been identified as a major risk factor. It might be associated with other conditions too. Patients with Legg-Calvé-Perthes disease present with painless limping gait with idiopathic etiology; it is unilateral in most of the cases. This paper reported a rare scenario of DDH associated with concurrent contralateral Legg-Calvé-Perthes disease.

A 5-year-old Saudi male patient, known case of developmental dysplasia of the right hip, which was managed operatively at a different hospital, presented in our outpatients clinic for right hip dysplasia and was found incidentally as having a limping gait due to left hip limited range of motion, following clinical assessment, pelvic radiographs demonstrated presence of subluxation at the right hip in addition to sclerosis, and irregularity of the left femoral head epiphysis. Right pelvic Dega osteotomy, femoral derotation osteotomy, varus osteotomy, and left hip arthrogram was examined under anesthesia with the positioning of the left hip at 45 degrees of abduction and 30 degrees of flexion to achieve the best coverage. Hip spica application was performed to correct DDH of the right hip. Repeated radiography at the subsequent visits showed better coverage of the femoral head on the right side. During a routine follow-up, there were also some osteonecrotic changes of the left femoral head that confirmed the diagnosis of left Legg-Calvé-Perthes disease.

Aetiology of Legg-Calvé-Perthes disease: A systematic review

BACKGROUND

Legg-Calvé-Perthes disease (LCPD) is a clinical condition affecting the femoral head of children during their growth. Its prevalence is set to be between 0.4/100000 to 29.0/100000 children less than 15 years of age with a peak of incidence in children aged from 4 years to 8 years. LCPD aetiology has been widely studied, but it is still poorly understood.

AIM

To analyse the available literature to document the up-to-date evidence on LCPD aetiology.

METHODS

A systematic review of the literature was performed regarding LCPD aetiology, using the following inclusion criteria: studies of any level of evidence, reporting clinical or preclinical results and dealing with the aetiology or pathogenesis of LCPD. Two reviewers searched the PubMed and Science Direct databases from their date of inception to the 20th of May 2018 in accordance with the Preferred Reporting Items for Systemic Reviews and Meta-Analyses guidelines. To achieve the maximum sensitivity of the search strategy, we combined the terms: ‘‘Perthes disease OR LCPD OR children avascular femoral head necrosis” with “pathology OR aetiology OR biomechanics OR genetics” as either key words or MeSH terms.

RESULTS

We include 64 articles in this review. The available evidence on LCPD aetiology is still debated. Several hypotheses have been researched, but none of them was found decisive. While emerging evidence showed the role of environmental risk factors and evidence from twin studies did not support a major role for genetic factors, a congenital or acquired predisposition cannot be excluded in disease pathogenesis. One of the most supported theories involved mechanical induced ischemia that evolved into avascular necrosis of the femoral head in sensible patients.

CONCLUSION

The literature available on the aetiology of LCPD presents major limitations in terms of great heterogeneity and a lack of high-profile studies. Although a lot of studies focused on the genetic, biomechanical and radiological background of the disease, there is a lack of consensus on one or multiple major actors of the etiopathogenesis. More studies are needed to understand the complex and multifactorial genesis of the avascular necrosis characterizing the disease.

Clinical and radiographic outcomes after femoral varus derotation osteotomy for Legg-Calvé-Perthes disease at 25 years follow-up: what are the determinants of outcome in the long term?

OBJECTIVE

The main purposes of the present study were to analyse the long-term clinical and radiographic results of femoral varus derotation osteotomy performed in a group of patients with the diagnosis of Legg-Calvé-Perthes (LCP) disease and to compare the effects of age, lateral pillar classification, radiographic stage according to Waldenström's classification, and the amount of varisation obtained on long-term results.

DESIGN

The study group consisted of 21 hips. The mean postoperative follow-up time was 25.1 years. The effect of age at the time of surgery, preoperative lateral pillar classification, Waldenström's classification, and the amount of varisation on Merle d'Aubigne score, Stulberg class, and presence of degenerative arthritis of the hip joint were assessed at the final follow-up.

RESULTS

Better clinical and radiographic outcomes were detected in patients operated younger than 10 years. The hips with lateral pillar group C involvement preoperatively were found to be significantly associated with worse clinical scores, worse radiographic outcome, and higher rate of degenerative arthritis. The overall rate of the hips with good radiologic outcome was 52.4%. 7 hips had degenerative arthritis at the final follow-up.

CONCLUSIONS

Femoral varus derotation osteotomy revealed a congruent joint in half of the operated hips and arthritis-free hip joint in 2/3 at 25 years follow-up. Age at the time of surgery and preoperative lateral pillar classification were the main determinants of the radiographic outcome whereas the factors significantly correlated with progression to degenerative arthritis were determined preoperative lateral pillar classification and Stulberg group at maturity.

Early outcomes of one-stage combined osteotomy in Legg-Calve´-Perthes disease

BACKGROUND

Legg-Calve´-Perthes disease (LCPD) is an idiopathic avascular necrosis of the femoral head. There are multiple approaches to the treatment of LCPD ranging from conservative management to a wide variety of surgical methods. Conservative management necessitates extreme degrees of abduction in an orthosis for a longer period of time which further jeopardize capital femoral head vascularity. Surgical containment methods are used in cases where it is desirable. Initial surgical containment methods are varus or varus-derotational osteotomy of the proximal femur or an innominate osteotomy as described by Salter and other pelvic osteotomies. The purpose of this study was to describe the early results of containment methods by one-stage combined osteotomy (femoral varus osteotomy and Salter innominate osteotomy) in patients with severe LCPD.

MATERIALS AND METHODS

23 children were operated in the age group of 4-9 years for LCPD by one-stage combined osteotomy procedure between January 2005 and June 2012. There were 19 boys and 4 girls, left hip involved in 10 cases and right in 13 cases. Preoperatively, they were classified according to Catterall, Joseph's stage and lateral pillar (LP) classification. Postoperatively, clinical results were evaluated in accordance with Ratliff classification and radiological assessment was made by Mose's index, modified Stulberg classification and Epiphyseal extrusion index.

RESULTS

Seventeen hips were Catterall group III, 6 in group IV and all had two or more "head-at-risk" signs. There were 2 patients with stage IIA, 15 were in stage IIB and 6 were in stage IIIA as classified by Joseph's stage of disease. According to LP classification, 11 patients were group B, 3 were group B/C and 9 were in group C. At an average followup of 5.4 years (range 2-9.5 years), the clinical results were good in 12, fair in 9 and poor in 2. According to Mose scale, 8 patients had good results, 13 fair results and 2 had poor results. Based on modified Stulberg classification, there were 10 patients in group A, 11 in group B and 2 in group C. The average preoperative extrusion index was 23.6% which improved postoperatively to 9.5% at latest followup.

CONCLUSIONS

The surgical treatment of LCPD with the best expected outcome is still a challenge. Advanced containment methods by one-stage combined osteotomy can be considered as an alternative treatment where femoral head subluxation or deformity which makes containment difficult or impossible by more conventional methods.

Endothelial nitric oxide synthase gene polymorphism is associated with Legg-Calvé-Perthes disease

The aim of this study was to assess the association of 27-bp variable number tandem repeat (VNTR) polymorphism in intron 4 and G894T polymorphism in exon 7 of the endothelial nitric oxide synthase (eNOS) gene with Legg-Calvé-Perthes disease (LCPD), and to provide a scientific basis for further research into the pathogenic mechanism. A total of 80 patients with LCPD and 100 healthy subjects were recruited in this case-control study. The 27-bp VNTR and G894T polymorphisms of the eNOS gene were genotyped using polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism, respectively, followed by agarose gel electrophoresis and DNA sequencing. Allelic and genotypic frequencies were computed in the two groups and subjected to statistical analysis. For the 27-bp VNTR polymorphism, individuals with LCPD showed a higher frequency of the ab genotype [27.5 vs. 14%; odds ratio (OR), 2.33; 95% confidence interval (CI), 1.10-4.92; P=0.024]. For the G894T polymorphism, the LCPD case group showed a higher frequency of the heterozygous genotype GT than the healthy control group (35 vs. 17%; OR, 2.67; 95% CI, 1.33-5.36; P=0.005). The results indicate that these eNOS gene polymorphisms may be a risk factor for LCPD. The 27-bp VNTR polymorphism in intron 4 and G894T polymorphism in exon 7 may be involved in the etiology of LCPD.

Comparative study of serum proteomes in Legg-Calve-Perthes disease

Background

Legg-Calve-Perthes Disease (LCPD) is an idiopathic osteonecrosis of the developing femoral head complicated by pain and disability of the hip joint. To date, the pathological mechanisms of LCPD are not well-known. This study screened the changes in serum protein expression in patients with LCPD.

Methods

Age- and sex-matched serum samples from 10 control subjects and 10 patients with LCPD were compared using the isobaric tags for relative and absolute quantification (iTRAQ) technique. Gene ontology analyses, KEGG pathway and functional network analyses were performed. Proteins of interest with large differences in expression, S100-A8, alpha-1-acid glycoprotein 1, haptoglobin and apolipoprotein E, were compared by western blotting.

Results

The disease/control ratios showed 26 proteins were significantly differentially expressed (all p < 0.05). Including higher abundances of complement factor H (1.44), complement C4-B (1.45), isocitrate dehydrogenase [NAD] subunit alpha (2.7) alpha-1-acid glycoprotein 1 (1.87), heptoglobin (1.53) and Ig lambda-2 chain C regions (1.46), and lower levels of apolipoprotein E (0.50), apolipoprotein F (0.60), apolipoprotein C-III (0.69), S100-A8 (0.73), S100-A9 (0.75) and prothrombin (0.77) in LCPD than in controls. The alpha-1-acid glycoprotein 1 and haptoglobin increases, and apolipoprotein E and S100-A8 decreases were confirmed by western blot. KEGG pathway analysis revealed these proteins were related to the complement and coagulation cascades, Staphylococcus aureus infection, PPAR signaling, fat digestion and absorption, and vitamin digestion and absorption. Functional network analysis suggested that the proteins were involved in lipid regulation.

Conclusions

The complement and coagulation cascades, and abnormal lipid metabolism may be involved in the pathogenesis of LCPD.