Six boys were examined during the second year of life, each with symptoms in one hip. The affected femoral capital epiphysis was smaller or more irregular (or both) than that of the unaffected hip but was neither subluxed nor dislocated. The subsequent radiographs revealed changes similar to those in severe Perthes' disease. Nevertheless, we give reasons for believing that this disorder in boys under two years of age should be distinguished from Perthes' disease

Forty-four children, treated conservatively for fracture of the shaft of a femur, were studied radiographically to assess the consequent increase in longitudinal growth of the bone. Overgrowth averaged 8.1 mm and was shown to be significantly greater in boys than in girls. Overgrowth did not appear to be influenced by the age of the patient, the type of injury, the type or site of the fracture, the amount of overlap of the fragments or by the handedness of the patient

Lumbar disc herniation (LDH) is uncommon in youth and few cases are treated surgically. Very few outcome studies exist for LDH surgery in this age group. Our aim was to explore differences in gender in pre-operative level of disability and outcome of surgery for LDH in patients aged ≤ 20 years using prospectively collected data.

From the national Swedish SweSpine register we identified 180 patients with one-year and 108 with two-year follow-up data ≤ 20 years of age, who between the years 2000 and 2010 had a primary operation for LDH.

Both male and female patients reported pronounced impairment before the operation in all patient reported outcome measures, with female patients experiencing significantly greater back pain, having greater analgesic requirements and reporting significantly inferior scores in EuroQol (EQ-5D-index), EQ-visual analogue scale, most aspects of Short Form-36 and Oswestry Disabilities Index, when compared with male patients. Surgery conferred a statistically significant improvement in all registered parameters, with few gender discrepancies. Quality of life at one year following surgery normalised in both males and females and only eight patients (4.5%) were dissatisfied with the outcome. Virtually all parameters were stable between the one- and two-year follow-up examination.

LDH surgery leads to normal health and a favourable outcome in both male and female patients aged 20 years or younger, who failed to recover after non-operative management.

Cite this article: Bone Joint J 2015;97-B:1675–82.

Aims. The aim of this study was to describe the incidence of refractures among children, following fractures of all long bones, and to identify when the risk of refracture decreases. Methods. All patients aged under 16 years with a fracture that had occurred in a bone with ongoing growth (open physis) from 1 May 2015 to 31 December 2020 were retrieved from the Swedish Fracture Register. A new fracture in the same segment within one year of the primary fracture was regarded as a refracture. Fracture localization, sex, lateral distribution, and time from primary fracture to refracture were analyzed for all long bones. Results. Of 40,090 primary fractures, 348 children (0.88%) sustained a refracture in the same long bone segment. The diaphyseal forearm was the long bone segment most commonly affected by refractures (n = 140; 3.4%). The median time to refracture was 147 days (interquartile range 82 to 253) in all segments of the long bones combined. The majority of the refractures occurred in boys (n = 236; 67%), and the left side was the most common side to refracture (n = 220; 62%). The data in this study suggest that the risk of refracture decreases after 180 days in the diaphyseal forearm, after 90 days in the distal forearm, and after 135 days in the diaphyseal tibia. Conclusion. Refractures in children are rare. However, different fractured segments run a different threat of refracture, with the highest risk associated with diaphyseal forearm fractures. The data in this study imply that children who have sustained a distal forearm fracture should avoid hazardous activities for three months, while children with a diaphyseal forearm fracture should avoid these activities for six months, and for four and a half months if they have sustained a diaphyseal tibia fracture. Cite this article: Bone Joint J 2023;105-B(8):928–934

Aims. The reduction in mobility due to hip diseases in children is likely to affect their physical activity (PA) levels. Physical inactivity negatively influences quality of life and health. Our aim was to objectively measure PA in children with hip disease, and correlate it with the Patient-Reported Outcomes Measurement Information System (PROMIS) Mobility Score. Methods. A total of 28 children (12 boys and 16 girls) with hip disease aged between 8and 17 years (mean 12 (SD 3)) were studied between December 2018 and July 2019. Children completed the PROMIS Paediatric Item Bank v. 2.0 – Mobility Short Form 8a and wore a hip accelerometer (ActiGraph) for seven consecutive days. Sedentary time (ST), light PA (LPA), moderate to vigorous PA (MVPA), and vigorous PA were calculated from the accelerometers' data. The PROMIS Mobility score was classified as normal, mild, and moderate functions, based on the PROMIS cut scores on the physical function metric. A one-way analysis of covariance (ANCOVA) was used to assess differences among mobility (normal; mild; moderate) and measured PA and relationships between these variables were assessed using bivariate Pearson correlations. Results. Children classified as normally functioning on the PROMIS had less ST (p = 0.002), higher MVPA, (p = 0.002) and VPA (p = 0.004) compared to those classified as mild or moderate function. A moderate correlation was evident between the overall PROMIS score and daily LPA (r = 0.462, n = 28; p = 0.013), moderate-to-vigorous PA (r = 0.689, n = 28; p = 0.013) and vigorous PA (VPA) (r = 0.535, n = 28; p = 0.013). No correlation was evident between the mean daily ST and overall PROMIS score (r = -0.282, n = 28; p = 0.146). Conclusion. PROMIS Pediatric Mobility tool correlates well with experimentally measured levels of physical activity in children with hip disease. We provide external validity for the use of this tool as a measure of physical activity in children. Cite this article: Bone Joint J 2021;103-B(2):405–410

Assessment of skeletal age is important in children’s orthopaedics. We compared two simplified methods used in the assessment of skeletal age. Both methods have been described previously with one based on the appearance of the epiphysis at the olecranon and the other on the digital epiphyses. We also investigated the influence of assessor experience on applying these two methods. Our investigation was based on the anteroposterior left hand and lateral elbow radiographs of 44 boys (mean: 14.4; 12.4 to 16.1 ) and 78 girls (mean: 13.0; 11.1 to14.9) obtained during the pubertal growth spurt. A total of nine observers examined the radiographs with the observers assigned to three groups based on their experience (experienced, intermediate and novice). These raters were required to determined skeletal ages twice at six-week intervals. The correlation between the two methods was determined per assessment and per observer groups. Interclass correlation coefficients (ICC) evaluated the reproducibility of the two methods. The overall correlation between the two methods was r = 0.83 for boys and r = 0.84 for girls. The correlation was equal between first and second assessment, and between the observer groups (r ≥ 0.82). There was an equally strong ICC for the assessment effect (ICC ≤ 0.4%) and observer effect (ICC ≤ 3%) for each method. There was no significant (p < 0.05) difference between the levels of experience. The two methods are equally reliable in assessing skeletal maturity. The olecranon method offers detailed information during the pubertal growth spurt, while the digital method is as accurate but less detailed, making it more useful after the pubertal growth spurt once the olecranon has ossified. Cite this article: Bone Joint J 2014;3:1556–60

The recognition of hips at risk of displacement in children with cerebral palsy (CP) is a difficult problem for the orthopaedic surgeon. The Gross Motor Function Classification System (GMFCS) and head–shaft angle (HSA) are prognostic factors for hip displacement. However, reference values for HSA are lacking. This study describes and compares the development of HSA in normal hips and children with CP. . We selected 33 children from a retrospective cohort with unilateral developmental dysplasia of the hip (DDH) (five boys, 28 girls) and 50 children (35 boys, 15 girls) with CP with GMFCS levels II to V. HSA of normal developing hips was measured at the contralateral hip of unilateral DDH children (33 hips) and HSA of CP children was measured in both hips (100 hips). Measurements were taken from the radiographs of the children at age two, four and seven years. The normal hip HSA decreased by 2° per year (p < 0.001). In children with CP with GMFCS levels II and III HSA decreased by 0.6° (p = 0.046) and 0.9° (p = 0.049) per year, respectively. The HSA did not alter significantly in GMFCS levels IV and V. . Between the ages of two and eight years, the HSA decreases in normal hips and CP children with GMFCS level, II to III but does not change in GMFCS levels IV to V. As HSA has a prognostic value for hip displacement, these reference values may help the orthopaedic surgeon to predict future hip displacement in children with CP. Cite this article: Bone Joint J 2015;97-B:1291–5

Aims. The goal of closed reduction (CR) in the treatment of developmental dysplasia of the hip (DDH) is to achieve and maintain concentricity of the femoral head in the acetabulum. However, concentric reduction is not immediately attainable in all hips and it remains controversial to what degree a non-concentric reduction is acceptable. This prospective study is aimed at investigating the dynamic evolution of the hip joint space after CR in DDH using MRI. Methods. A consecutive series of patients with DDH who underwent CR since March 2014 were studied. Once the safety and stability were deemed adequate intraoperatively, reduction was accepted regardless of concentricity. Concentricity was defined when the superior joint space (SJS) and medial joint space (MJS) were both less than 2 mm, based on MRI. A total of 30 children, six boys and 24 girls, involving 35 hips, were recruited for the study. The mean age at CR was 13.7 months (3.5 to 27.6) and the mean follow-up was 49.5 months (approximately four years) (37 to 60). The joint space was evaluated along with the interval between the inverted and everted limbus. Results. Only three hips (8.6%) were fully concentric immediately after CR. During follow-up, 24 hips (68.6%) and 27 hips (77.1%) became concentric at six months and one year, respectively. Immediate SJS after CR decreased from 3.51 mm to 0.79 mm at six months follow-up (p = 0.001). SJS in the inverted group decreased from 3.75 mm to 0.97 mm at six months follow-up. SJS or MJS in the everted group were less than those in the inverted group at each time of follow-up (p = 0.008, p = 0.002). Conclusion. A stable, safe but non-concentric reduction achieved before the age of two years appears to improve over time with nearly 80% of hips becoming fully concentric by one year. Cite this article: Bone Joint J 2020;102-B(5):618–626

Aims. The purpose of this study was to report the long-term results of extendable endoprostheses of the humerus in children after the resection of a bone sarcoma. Methods. A total of 35 consecutive patients treated with extendable endoprosthetic replacement of the humerus in children were included. There were 17 boys and 18 girls in the series with a median age at the time of initial surgery of nine years (interquartile range (IQR) 7 to 11). Results. The median follow-up time was 10.6 years (IQR 3.9 to 20.4). The overall implant survival at ten years was 75%. Complications occurred in 13 patients (37%). Subluxation at the proximal humerus occurred in 19 patients (54%) but only six (17%) were symptomatic. Subluxation was seen more commonly in children under the age of nine years (86%) than in those aged nine years or more (33%) (p = 0.002). Implant failure occurred in nine patients (26%): the most common cause was aseptic loosening (four patients, 11%). Lengthening of the implant was carried out in 23 patients (66%). At final follow up, three patients had a limb that was shortened by 5 cm or more. The mean Musculoskeletal Tumor Society (MSTS) functional score was 79% (73% to 90%). Conclusion. Extendable endoprosthetic replacement is a reliable method of reconstructing humerus after excision of a bone sarcoma. Children who are less than nine years old have a high risk of subluxation. Cite this article: Bone Joint J 2020;102-B(1):64–71

Aims. The management of completely displaced fractures of the distal radius in children remains controversial. This study evaluates the outcomes of surgical and non-surgical management of ‘off-ended’ fractures in children with at least two years of potential growth remaining. Methods. A total of 34 boys and 22 girls aged 0 to ten years with a closed, completely displaced metaphyseal distal radial fracture presented between 1 November 2015 and 1 January 2020. After 2018, children aged ten or under were offered treatment in a straight plaster or manipulation under anaesthesia with Kirschner (K-)wire stabilization. Case notes and radiographs were reviewed to evaluate outcomes. In all, 16 underwent treatment in a straight cast and 40 had manipulation under anaesthesia, including 37 stabilized with K-wires. Results. Of the children treated in a straight cast, all were discharged with good range of mo (ROM). Five children were discharged at six to 12 weeks with no functional limitations at six-month follow-up. A total of 11 children were discharged between 12 and 50 weeks with a normal ROM and radiological evidence of remodelling. One child had a subsequent diaphyseal fracture proximal to the original injury four years after the initial fracture. Re-displacement with angulation greater than 10° occurred for 17 children who had manipulation under anaesthesia. Four had a visible cosmetic deformity at discharge and nine had restriction of movement, with four requiring physiotherapy. One child developed over- granulation at the pin site and one wire became buried, resulting in a difficult retrieval in clinic. No children had pin site infections. Conclusion. Nonoperative management of completely displaced distal radial fractures in appropriately selected cases results in excellent outcomes without exposing the child to the risks of surgery. This study suggests that nonoperative management of these injuries is a viable and potentially underused strategy. Cite this article: Bone Joint J 2021;103-B(5):902–907

Aims. The Ponseti method is an effective evidence-based treatment for clubfoot. It uses gentle manipulation to adjust the position of the foot in serial treatments towards a more physiological position. Casting is used to hold the newly achieved position. At first, the foot resists the new position imposed by the plaster cast, pressing against the cast, but over time the tissues are expected to adapt to the new position and the force decreases. The aim of this study was to test this hypothesis by measuring the forces between a clubfoot and the cast during treatment with the Ponseti method. Patients and Methods. Force measurements were made during the treatment of ten idiopathic clubfeet. The mean age of the patients was seven days (2 to 30); there were nine boys and one girl. Force data were collected for several weeks at the location of the first metatarsal and the talar neck to determine the adaptation rate of the clubfoot. Results. In all measurements, the force decreased over time. The median (interquartile range) half-life time was determined to be at 26 minutes (20 to 53) for the first metatarsal and 22 minutes (9 to 56) for the talar neck, suggesting that the tissues of the clubfoot adapt to the new position within several hours. Conclusion. This is the first study to provide objective force data that support the hypothesis of adaptation of the idiopathic clubfoot to the new position imposed by the cast. We showed that the expected decrease in corrective force over time does indeed exist and adaptation occurs after a relatively short period of time. The rapid reduction in the forces acting on the foot during treatment with the Ponseti method may allow significant reductions in the interval between treatments compared with the generally accepted period of one week

Aims. We report the use of the distal radius and ulna (DRU) classification for the prediction of peak growth (PG) and growth cessation (GC) in 777 patients with idiopathic scoliosis. We compare this classification with other commonly used parameters of maturity. Patients and Methods. The following data were extracted from the patients’ records and radiographs: chronological age, body height (BH), arm span (AS), date of menarche, Risser sign, DRU grade and status of the phalangeal and metacarpal physes. The mean rates of growth were recorded according to each parameter of maturity. PG was defined as the summit of the curve and GC as the plateau in deceleration of growth. The rates of growth at PG and GC were used for analysis using receiver operating characteristic (ROC) curves to determine the strength and cutoff values of the parameters of growth. Results. The most specific grades for PG using the DRU classification were radial grade 6 and ulnar grade 5, and for GC were radial grade 9 and ulnar grade 7. The DRU classification spanned both PG and GC, enabling better prediction of these clinically relevant stages than other methods. The rate of PG (≥ 0.7 cm/month) and GC (≤ 0.15 cm/month) was the same for girls and boys, in BH and AS measurements. Conclusion. This is the first study to note that the DRU classification can predict both PG and GC, providing evidence that it may aid the management of patients with idiopathic scoliosis. Cite this article: Bone Joint J 2016;98-B:1689–96

Aims. The aim of this study was to evaluate the efficacy of the surgical dislocation approach and modified trapdoor procedure for the treatment of chondroblastoma of the femoral head. Patients and Methods. A total of 17 patients (ten boys, seven girls; mean age 16.4 years (11 to 26)) diagnosed with chondroblastoma of the femoral head who underwent surgical dislocation of the hip joint, modified trapdoor procedure, curettage, and bone grafting were enrolled in this study and were followed-up for a mean of 35.9 months (12 to 76). Healing and any local recurrence were assessed via clinical and radiological tests. Functional outcome was evaluated using the Musculoskeletal Tumour Society scoring system (MSTS). Patterns of bone destruction were evaluated using the Lodwick classification. Secondary osteoarthritis was classified via radiological analysis following the Kellgren–Lawrence grading system. Steinberg classification was used to evaluate osteonecrosis of the femoral head. Results. The epiphyseal plate was open, closing, and closed in five, five, and seven patients, respectively. In total, eight, six, and three patients were classified as having Lodwick classification IA, IB, and IC, respectively. Allogeneic and autogenous bone grafting was used in 13 and four patients, respectively. All patients had good bone healing and no local recurrence was observed. One patient developed osteonecrosis of the femoral head (Steinberg IA) and one developed secondary osteoarthritis of the hip joint (Kellgren–Lawrence Grade II). The mean postoperative MSTS functional score was 27.7 (24 to 30). Conclusion. Surgical dislocation and modified trapdoor procedures are safe and effective techniques for treating chondroblastoma in the femoral head. Cite this article: Bone Joint J 2019;101-B:732–738

Aims. The aim of this study was to identify the association between asymmetrical skin creases of the thigh, buttock or inguinal region and pathological developmental dysplasia of the hip (DDH). Patients and Methods. Between 1 January 1996 and 31 December 2016, all patients referred to our unit from primary or secondary care with risk factors for DDH were assessed in a “one stop” clinic. All had clinical and sonographic assessment by the senior author (RWP) with the results being recorded prospectively. The inclusion criteria for this study were babies and children referred with asymmetrical skin creases. Those with a neurological cause of DDH were excluded. The positive predictive value (PPV) for pathological DDH was calculated. Results. A total of 105 patients met the inclusion criteria. There were 71 girls and 34 boys. Only two were found to have pathological DDH. Both also had unilateral limited abduction of the hip in flexion and a positive Galeazzi sign with apparent leg-length discrepancy. Thus, if the specialist examination of a patient with asymmetrical skin creases was normal, the PPV for DDH was 0%. Conclusion. Isolated asymmetrical skin creases are an unreliable clinical sign in the diagnosis of pathological DDH. Greater emphasis should be placed on the presence of additional clinical signs to guide radiological screening in babies and children. Cite this article: Bone Joint J 2018;100-B:675–9

Aims. Delayed diagnosis is a well-known complication of a Monteggia fracture-dislocation. If left untreated, the dislocated radial head later becomes symptomatic. The purposes of this study were firstly, to evaluate the clinical and radiological results of open reduction of the radial head and secondly, to identify the factors that may affect the outcome of this procedure. Materials and Methods. This retrospective study evaluated 30 children with a chronic Monteggia lesion. There were 18 boys and 12 girls with a mean age of 7.4 years (4 to 13) at the time of open reduction. The mean interval to surgery, after the initial fracture, was 23.4 months (6 to 120). Clinical grading used a Kim modified elbow score: radiological outcome was recorded. The effect of the patient’s age, gender, duration from initial injury, Bado classification, and annular ligament reconstruction were analyzed. The mean follow-up was 42.2 months (15 to 20). Results. The Kim elbow scores evaluated at the last clinic visit were excellent in 23 patients, good in three, fair in two, and poor in two. A majority of the patients were found to have significant improvement of elbow flexion (p < 0.001). Six met the criteria of a fair radiological outcome; four of these were operated on more than 24 months after the initial injury, and three had surgery after the age of 11. Univariate analysis failed to find any factor that was significantly associated with a fair or poor outcome. Conclusion. Good clinical and radiological outcomes can be expected in most patients. Osteoarthritic changes were associated with age > 11 years and/or a delay of treatment of > 24 months. However, no statistically significant factor could be identified which correlated with an unfavourable outcome. Cite this article: Bone Joint J 2018;100-B:1117–24

Aims. The primary aim of this study was to evaluate the performance and safety of magnetically controlled growth rods in the treatment of early onset scoliosis. Secondary aims were to evaluate the clinical outcome, the rate of further surgery, the rate of complications, and the durability of correction. Patients and Methods. We undertook an observational prospective cohort study of children with early onset scoliosis, who were recruited over a one-year period and followed up for a minimum of two years. Magnetically controlled rods were introduced in a standardized manner with distractions performed three-monthly thereafter. Adverse events which were both related and unrelated to the device were recorded. Ten children, for whom relevant key data points (such as demographic information, growth parameters, Cobb angles, and functional outcomes) were available, were recruited and followed up over the period of the study. There were five boys and five girls. Their mean age was 6.2 years (2.5 to 10). Results. The mean coronal Cobb angle improved from 57.6° (40° to 81°) preoperatively, 32.8° (28° to 46°) postoperatively, and 41° (19° to 57°) at two years. Five children had an adverse event, with four requiring return to theatre, but none were related to the device. There were no neurological complications or infections. No devices failed. One child developed a proximal junctional kyphosis. The mean gain in spinal column height from T1 to S1 was 45.4 mm (24 to 81) over the period of the study. Conclusion. Magnetically controlled growth rods provide an alternative solution to traditional growing rods in the surgical management of children with early onset scoliosis, supporting growth of the spine while controlling curve progression. Their use has clear psychosocial and economic benefits, with the reduction of the need for repeat surgery as required with traditional growing rods. Cite this article: Bone Joint J 2018;100-B:507–15

We have attempted to describe the epidemiology of femoral fractures in children in the West Midlands region of the National Health Service in England. Our source of data was the Regional Hospital Episode Statistics database for the years 1991-2 to 2001-2. Cases were defined as emergency hospital admissions in patients aged under 16 years, with a diagnostic code of femoral fractures in any field, and resident in the West Midlands. Between 1991-2 and 2001-2, 3272 children aged under 16 years with femoral fractures were admitted to hospital. The crude incidence during this period decreased from 0.33 to 0.22 femoral fractures/1000/year. Those caused by traffic accidents decreased by 43%, and by falls by 29%. The peak age-gender-specific incidence (0.91/1000/year) was in two-year-old boys, and this was 50% higher than in the next highest age-gender group. In the first year of life, the incidence in boys and girls was the same. Thereafter the rate in boys exceeded that in girls, varying from 1.6 times at 11 years to 4.7 times at 14 years. Falls accounted for 49% of the fractures, varying from 77% in one-year-olds to 26% in eight-year-old children. Traffic accidents were responsible for 26% of fractures varying from 55% in ten-year-old to 2% in one-year-old children. Maltreatment was recorded in 1.3% of all cases, and in 8.5% of children under one year. Twice as many fractures were seen in May to August than in January (winter). The rates of fractures were associated with deprivation for all age-gender groups. Fractures of the shaft accounted for 58% of all fractures, varying from 70% in three-year-old to 34% in 13-year-old children. Our findings show that there has been a decrease in the incidence of femoral fractures during the 1990s and early 2000s. Two-year-old boys had twice the rate than any other single-year age-gender group. More deprived areas had much higher rates which suggests the potential for greater prevention. A relatively low rate of maltreatment was recorded compared with that in some other studies

Aims

Medial humeral epicondyle fractures (MHEFs) are common elbow fractures in children. Open reduction should be performed in patients with MHEF who have entrapped intra-articular fragments as well as displacement. However, following open reduction, transposition of the ulnar nerve is disputed. The aim of this study is to evaluate the need for ulnar nerve exploration and transposition.

Aims

Perthes’ disease (PD) is a childhood hip disorder that can affect the quality of life in adulthood due to femoral head deformity and osteoarthritis. There is very little data on how PD patients function as adults, especially from the patients’ perspective. The purpose of this study was to collect treatment history, demographic details, the University of California, Los Angeles activity score (UCLA), the 36-Item Short Form survey (SF-36) score, and the Hip disability and Osteoarthritis Outcome score (HOOS) of adults who had PD using a web-based survey method and to compare their outcomes to the outcomes from an age- and sex-matched normative population.

Aims. Magnetically controlled growing rods (MCGRs) allow non-invasive correction of the spinal deformity in the treatment of early-onset scoliosis. Conventional growing rod systems (CGRS) need repeated surgical distractions: these are associated with the effect of the ‘law of diminishing returns’. The primary aim of this study was to quantify this effect in MCGRs over sequential distractions. . Patients and Methods. A total of 35 patients with a maximum follow-up of 57 months were included in the study. There were 17 boys and 18 girls with a mean age of 7.4 years (2 to 14). True Distraction (TD) was determined by measuring the expansion gap on fluoroscopy. This was compared with Intended Distraction (ID) and expressed as the ‘T/I’ ratio. The T/I ratio and the Cobb angle were calculated at several time points during follow-up. Results. The mean follow-up was 30 months (6 to 57). There was a significant decrease in the mean T/I ratio over time (convex rod at 3 months 0.81, . sd. 0.58 vs 51 months 0.17, . sd . 0.16, p = 0.0001; concave rod at 3 months 0.93, . sd. 0.67 vs 51 months 0.18, . sd. 0.15, p = 0.0001). A linear decline of the mean T/I ratios was noted for both convex rods (r. 2. = 0.90, p = 0.004) and concave rods (r. 2. = 0.81, p = 0.015) over 51 months. At the 24-month follow-up stage, there was a significant negative correlation between the mean T/I ratio of the concave rod with weight (r = -0.59, p = 0.01), age (r = -0.59, p = 0.01), and BMI of the child (r = -0.54, p = 0.01). Conclusions. The ‘law of diminishing returns’ is also seen after serial distraction using MCGR. Compared to previously published data for CGRS, there is a gradual linear decline rather than a rapid initial decline in lengthening. In older, heavier children a reduced distraction ratio in the concave rod of the MCGR device is noted over time. Cite this article: Bone Joint J 2017;99-B:1658–64