Aims. Though the pathogenesis of Legg-Calve-Perthes disease (LCPD) is unknown, repetitive microtrauma resulting in deformity has been postulated. The purpose of this study is to trial a novel upright MRI scanner, to determine whether any deformation occurs in femoral heads affected by LCPD with weightbearing. Methods. Children affected by LCPD were recruited for analysis. Children received both standing weightbearing and supine scans in the MROpen upright MRI scanner, for coronal T1 GFE sequences, both hips in field of view. Parameters of femoral head height, width, and lateral extrusion of affected and unaffected hips were assessed by two independent raters, repeated at a one month interval. Inter- and intraclass correlation coefficients were determined. Standing and supine measurements were compared for each femoral head. Results. Following rigorous protocol development in healthy age-matched volunteers, successful scanning was performed in 11 LCPD-affected hips in nine children, with seven unaffected hips therefore available for comparison. Five hips were in early stage (1 and 2) and six were in late stage (3 and 4). The mean age was 5.3 years. All hips in early-stage LCPD demonstrated dynamic deformity on weightbearing. Femoral head height decreased (mean 1.2 mm, 12.4% decrease), width increased (mean 2.5 mm, 7.2% increase), and lateral extrusion increased (median 2.5 mm, 23% increase) on standing weightbearing MRI compared to supine scans. Negligible deformation was observed in contra-lateral unaffected hips, with less deformation observed in late-stage hips. Inter- and intraclass reliability for all measured parameters was good to excellent. Conclusion. This pilot study has described an effective novel research investigation for children with LCPD. Femoral heads in early-stage LCPD demonstrated dynamic deformity on weightbearing not previously seen, while unaffected hips did not. Expansion of this protocol will allow further translational study into the effects of loading hips with LCPD. Cite this article: Bone Joint Open 2020;1-7:364–369

This pilot study aims to investigate the utility and feasibility of a unique upright MR scan for imaging hips affected by Legg-Calve-Perthes Disease (LCPD) with patient standing up, in comparison to the standard supine scans. Protocol development using this unique upright MRI included healthy adult and child volunteers. Optimum patient positioning in a comparable way between supine to standing was assessed. The balance between shorter scan time (to what a child can tolerate) and longer scan time (for better image acquisition). The study protocol has begun in 2 children with LCPD. Patient recruitment continues. Early results indicate a dynamic deformity of the femoral head in early stage LCP disease. Femoral epiphysis height decreased on standing (7.8 to 6.8mm), width increased on standing (16.6 to 20.9mm) and lateral extrusion increased (3.5 to 4.1mm). Overall epiphyseal shape changed from trapezoidal (LCP femoral head when supine) to flattened triangular (LCP femoral head when standing). Differences were thus demonstrated in all parameters of bony epiphyseal height, width, extrusion and shape of a femoral head with LCP Disease when the child stood and loaded the affected hip. Satisfactory image acquisition was possible with Coronal T1 GFE sequences, with both hips in the Field of View. 2.5min scans were performed with the child standing first, then supine. Hip position was comparable when standing and supine. Longer scans were not tolerated by younger children, more so those with LCP disease. To our knowledge this is the first reported use of standing MRI in LCPD. A dynamic deformity has been demonstrated, with flattening, widening and worsened lateral extrusion when the child is standing compared to supine. This proof of concept investigation demonstrates the feasibility of upright MRI scanning and may demonstrate previously undetected deformity

In Norway total joint replacement after hip dysplasia is reported more commonly than in neighbouring countries, implying a higher prevalence of the condition. We report on the prevalence of radiological features associated with hip dysplasia in a population of 2081 19-year-old Norwegians. The radiological measurements used to define hip dysplasia were Wiberg’s centre-edge (CE) angle at thresholds of < 20° and < 25°, femoral head extrusion index <  75%, Sharp’s angle > 45°, an acetabular depth to width ratio < 250 and the sourcil shape assessed subjectively. The whole cohort underwent clinical examination of their range of hip movement, body mass index (BMI), and Beighton hypermobility score, and were asked to complete the EuroQol (EQ-5D) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC). The prevalence of hip dysplasia in the cohort varied from 1.7% to 20% depending on the radiological marker used. A Wiberg’s CE angle <  20° was seen in 3.3% of the cohort: 4.3% in women and 2.4% in men. We found no association between subjects with multiple radiological signs indicative of dysplasia and BMI, Beighton score, EQ-5D or WOMAC. Although there appears to be a high prevalence of hip dysplasia among 19-year-old Norwegians, this is dependent on the radiological parameters applied. Cite this article: Bone Joint J 2013;95-B:279–85

We treated eight dysplastic acetabula in six skeletally mature patients with Down’s syndrome by a modified Bernese periacetabular osteotomy. The mean age at the time of surgery was 16.5 years (12.8 to 28.5). Mean length of follow-up was five years (2 to 10.4). Pre-operatively the mean (Tönnis) acetabular angle was 28°, the centre-edge angle was −9°, and the extrusion index was 60%; post-operatively they were 3°, 37°, and 17%, respectively. Two patients with post-operative (Tönnis) acetabular angles > 10° developed subluxation post-operatively and required secondary varus derotation femoral osteotomies. Another patient developed a late labral tear which was treated arthroscopically. All eight hips remain clinically stable, and are either asymptomatic or symptomatically improved. These results suggest that the modified Bernese periacetabular osteotomy can be used successfully in the treatment of acetabular dysplasia in patients with Down’s syndrome

Purpose. To establish the early outcome, satisfaction and complications of sinus tarsi implants in the management of symptomatic flexible flatfeet for a paediatric population. Methods and results. We included all patients aged 18 years or less who were treated for flexible flatfeet with a sinus tarsi implant between January 2010 and June 2012. We excluded patients who had a history of clubfeet or tarsal coalition. 34 patients had 59 implants. The mean age at surgery was 13.7 yrs (9–17 yrs), with mean follow-up of 22 months (range 10–35). Mean AOFAS improved from 65.7 to 87.9 (p<0.001), with an improvement in AOFAS pain scores (p=0.0001). Radiographic correction occurred in all feet, with average improvement of the anteroposterior talar-second metatarsal angle of 16 degrees, and the lateral talar-first metatarsal angle of 9 degrees. Implant placement satisfaction rate was 86%, with 81% claiming that they would have the procedure again. Complications included peroneal spasm (8%), extrusion (7%), revision (5%), and removal (5%). Peroneal spasm was recalcitrant in 3 of the 5 cases, and those with spasm had a higher average forefoot abduction measurement (35 degrees) than the remaining treated cases (25 degrees). Conclusion. In paediatric patients with flexible flatfeet, utilisation of the sinus tarsi implant has good short-term outcome, with our failure and revision rates comparable to other published studies in the adult population. We introduce the concept of isolated subtalar hyperlaxity which appeared to be a distinct etiological factor. A learning curve in assessing implant size was noted. Overcorrection and implant migration were the indications for revision surgery. Severe forefoot abduction appears to have a poorer outcome, and may be associated with peroneal spasm. Level of evidence: IV

Femoral head deformity can be a devastating outcome in a small percentage of patients with Perthes' disease. Deformities usually start during the fragmentation stage. In this study, we aimed to determine the effects of Vitamin D deficiency on the natural history of Perthes' disease. Patients with Perthes' disease and Vitamin D deficiency presenting to our unit in the last 3 years were identified. All X-rays were reviewed retrospectively to determine the duration of the fragmentation and ossification stages. Treatment methods were obtained from the notes. Late presenters (i.e. after fragmentation stage) were excluded. In our unit, Vitamin D deficiency is diagnosed if levels <72 nmol/L. Fifteen patients (17 hips) with Perthes' disease were found to be Vitamin D deficient. Levels ranged from (18–71 nmol/L). The mean length of the fragmentation stage was 15.7 months which is significantly higher than quoted literature figures (8 months). Ossification stage duration was 18.8 months which was comparable to quoted figures. However, patients with severe Vitamin D deficiency (< 52 nmol/L) were found to have longer ossification stage (20.6 months) compared with patients with mild deficiency (52–72 nmol/L) (16.4 months). Seven out of 16 patients (44%) required surgical containment which is significantly higher than the usually low rates of surgical intervention. The critical fragmentation stage in Vitamin D deficiency is significantly longer putting the femoral head at higher risk of deformity and extrusion. This leads to higher rates of surgical containment. Also the severity of Vitamin D deficiency might be an important determinant of the period of time required for ossification and healing. Vitamin D level is an important prognostic factor and must be measured in all patients with Perthes' disease. Prescribing Vitamin D supplements is advisable in this group of patients. However, the effects of these supplements on the course of the disease requires further research. Level of evidence: III

Aim. Shelf acetabuloplasty is part of the armamentarium for the treatment of Legg-Perthes-Calve disease. Surgeons have used it to increase the anterolateral cover of the deformed head in advanced stages of the disease. However, others, including the senior author, advocate its use for containment of the diseased femoral head earlier in the disease, for both the prevention of further femoral head extrusion and as an aid in the remodelling process. The current study presents the results of this procedure performed from August 1999 to February 2010. Method. Full sets of x-rays were available for 44 patients (45 hips). Three other bilateral cases were treated with a unilateral shelf. Results. This series includes 34 boys and 10 girls with a mean age at diagnosis of 7.5 years (range 3.9 to 15.3). The average time to heal was 37.6 months (range 12–62.4). Over 80% of the hips were Elizabethtown stages 1 and 2 and almost 70% were Herring B at the time of surgery. However, 66% presented with more than two head-at-risk signs. Reimer's migration index and the deformity index were measured on initial, preoperative, postoperative and healed x-rays. The average deformity index at those four time points was significantly related to their final Stulberg classification. CE angles increased and Sharp angles decreased significantly as a result of treatment. Although many shelf grafts showed progressive resorption, the overall acetabular depth increased. At the healed stage, 82.2% of patients were Stulberg 3 or less, denying any pain and with full range of movement whilst 17.8% were classified as Stulberg 4. One of them required a Sugioka valgus osteotomy due to continuous pain. Conclusion. Shelf acetabuloplasty should be considered not only a salvage procedure but also indicated for the containment of extruded hips in earlier stages of Perthes disease

Aims

Guided growth using eight-plates is commonly used for correction of angular limb deformities in growing children. The principle is of tethering at the physeal periphery while enabling growth in the rest of the physis. The method is also applied for epiphysiodesis to correct limb-length discrepancy (LLD). Concerns have been raised regarding the potential of this method to create an epiphyseal deformity. However, this has not been investigated. The purpose of this study was to detect and quantify the occurrence of deformities in the proximal tibial epiphysis following treatment with eight-plates.

Children presenting with Perthes’ disease before their sixth birthday are considered to have a good prognosis. We describe 166 hips in children in this age group. The mean age at onset of the disease was 44 months (22 to 72). Mild forms (Catterall I and II) were treated conservatively and severe forms (Catterall III and IV) either conservatively or operatively. The aim of the former treatment was to restrict weight-bearing. Operative treatment consisted of innominate osteotomy and was indicated by a Conway type-B appearance on the bone scan. All the patients were followed to skeletal maturity with a mean follow-up of 11 years (8 to 15).

The end results were evaluated radiologically using the classifications of Stulberg and Mose. A total of 50 hips were Catterall grade-I or grade-II, 65 Catterall grade-III and 51 Catterall grade-IV. All hips with mild disease had a good result at skeletal maturity. Of the hips with severe disease 78 (67.3%) had good (Stulberg I and II), 26 (22.4%) fair (Stulberg III) and 12 (10.3%) poor results (Stulberg IV and V). Of the Catterall grade-III hips 38 were treated conservatively of which 31 (81.6%) had a good result, six (15.8%) a fair and one (2.6%) a poor result. Operative treatment was carried out on 27 Catterall grade-III hips, of which 21 (77.8%) had a good, four (14.8%) a fair and two (7.4%) a poor result. By comparison conservative treatment of 19 Catterall grade-IV hips led to ten (52.7%) good, seven (36.8%) fair and two (10.5%) poor results. Operative treatment was carried out on 32 Catterall grade-IV hips, of which 16 (50.0%) had a good, nine (28.1%) a fair and seven (21.9%) a poor result.

We confirm that the prognosis in Perthes’ disease is generally good when the age at onset is less than six years. In severe disease there is no significant difference in outcome after conservative or operative treatment (p > 0.05). Catterall grade-III hips had a better outcome according to the Stulberg and Mose criteria than Catterall grade-IV hips, regardless of the method of treatment.

The deformity index is a new radiological measurement of the degree of deformity of the femoral head in unilateral Perthes’ disease. Its values represent a continuous outcome measure of deformity incorporating changes in femoral epiphyseal height and width compared with the unaffected side. The sphericity of the femoral head in 30 radiographs (ten normal and 20 from patients with Perthes’ disease) were rated blindly as normal, mild, moderate or severe by three observers. Further blinded measurements of the deformity index were made on two further occasions with intervals of one month.

There was good agreement between the deformity index score and the subjective grading of deformity. Intra- and interobserver agreement for the deformity index was high. The intraobserver intraclass correlation coefficient for each observer was 0.98, 0.99 and 0.97, respectively, while the interobserver intraclass correlation coefficient was 0.98 for the first and 0.97 for the second set of calculations.

We also reviewed retrospectively 96 radiographs of children with Perthes’ disease, who were part of a multicentre trial which followed them to skeletal maturity. We found that the deformity index at two years correlated well with the Stulberg grading at skeletal maturity. A deformity index value above 0.3 was associated with the development of an aspherical femoral head. Using a deformity index value of 0.3 to divide groups for risk gives a sensitivity of 80% and specificity of 81% for predicting a Stulberg grade of III or IV.

We conclude that the deformity index at two years is a valid and reliable radiological outcome measure in unilateral Perthes’ disease.

Most surgeons favour removing forearm plates in children. There is, however, no long-term data regarding the complications of retaining a plate. We present a prospective case series of 82 paediatric patients who underwent plating of their forearm fracture over an eight-year period with a minimum follow-up of two years. The study institution does not routinely remove forearm plates. A total of 116 plates were used: 79 one-third tubular plates and 37 dynamic compression plates (DCP). There were 12 complications: six plates (7.3%) were removed for pain or stiffness and there were six (7.3%) implant-related fractures. Overall, survival of the plates was 85% at 10 years. Cox regression analysis identified radial plates (odds ratio (OR) 4.4, p = 0.03) and DCP fixation (OR 3.2, p = 0.02) to be independent risk factors of an implant-related fracture. In contrast ulnar plates were more likely to cause pain or irritation necessitating removal (OR 5.6, p = 0.04).

The complications associated with retaining a plate are different, but do not occur more frequently than the complications following removal of a plate in children.

We evaluated radiological hip remodelling after shelf acetabuloplasty and sought to identify prognostic factors in 25 patients with a mean age of 8.9 years (7.0 to 12.3) who had unilateral Perthes’ disease with reducible subluxation of the hip in the fragmentation stage.

At a mean follow-up of 6.7 years (3.2 to 9.0), satisfactory remodelling was observed in 18 hips (72%). The type of labrum in hip abduction, as determined by intra-operative dynamic arthrography, was found to be a statistically significant prognostic factor (p = 0.012).

Shelf acetabuloplasty as containment surgery seems to be best indicated for hips in which there is not marked collapse of the epiphysis and in which the extruded epiphyseal segment slips easily underneath the labrum on abduction, without imposing undue pressure on the lateral edge of the acetabulum.

The bicompartmental acetabulum is one of the morphological changes which may be seen in children with Legg-Calvé-Perthes’ disease. Three-dimensional CT and MRI were used to analyse the detailed morphology of the acetabulum with special reference to its inner surface, in 16 patients with Perthes’ disease and a bicompartmental acetabulum.

The bicompartmental appearance was seen on the coronal plane image through the acetabular fossa. The lunate surface was seen to grow laterally resulting in an increased mediolateral thickness of the triradiate cartilage. On the horizontal plane images, the acetabular fossa had deepened and had a distinct prominence at its posterior border. The combination of these morphological changes resulted in a bicompartmental appearance on plain radiography. Acetabular bicompartmentalisation appears to be the result of an imbalance of growth between the cartilage-covered lunate surface and the cartilage-devoid acetabular fossa.