This study evaluated the effect of limb lengthening on longitudinal growth in patients with achondroplasia. Growth of the lower extremity was assessed retrospectively by serial radiographs in 35 skeletally immature patients with achondroplasia who underwent bilateral limb lengthening (Group 1), and in 12 skeletally immature patients with achondroplasia who did not (Group 2). In Group 1, 23 patients underwent only tibial lengthening (Group 1a) and 12 patients underwent tibial and femoral lengthening sequentially (Group 1b). The mean lengthening in the tibia was 9.2 cm (59.5%) in Group 1a, and 9.0 cm (58.2%) in the tibia and 10.2 cm (54.3%) in the femur in Group 1b. The mean follow-up was 9.3 years (8.6 to 10.3). The final mean total length of lower extremity in Group 1a was 526.6 mm (501.3 to 552.9) at the time of skeletal maturity and 610.1 mm (577.6 to 638.6) in Group 1b, compared with 457.0 mm (411.7 to 502.3) in Group 2. However, the mean actual length, representing the length solely grown from the physis without the length of distraction, showed that there was a significant disturbance of growth after limb lengthening. In Group 1a, a mean decrease of 22.4 mm (21.3 to 23.1) (4.9%) was observed in the actual limb length when compared with Group 2, and a greater mean decrease of 38.9 mm (37.2 to 40.8) (8.5%) was observed in Group 1b when compared with Group 2 at skeletal maturity. In Group 1, the mean actual limb length was 16.5 mm (15.8 to 17.2) (3.6%) shorter in Group 1b when compared with Group 1a at the time of skeletal maturity. Premature physeal closure was seen mostly in the proximal tibia and the distal femur with relative preservation of proximal femur and distal tibia. We suggest that significant disturbance of growth can occur after extensive limb lengthening in patients with achondroplasia, and therefore, this should be included in pre-operative counselling of these patients and their parents

Introduction. This study aims to evaluate the effect of using different types of fixator on the quality of callus and complications during distraction osteogenesis in patients with achondroplasia. Materials and Methods. Forty-nine achondroplasia patients with a minimum follow-up of 36 months who underwent limb lengthening between 2005 and 2017 with external fixator only were included. Thirty-three of the patients underwent lengthening using classical Ilizarov frame, while spatial frame used for sixteen. Regenerate quality is evaluated according to the Li classification on the X-ray taken one month after the end of the distraction. Complications were noted in the follow-up period. Results. The mean age at the time of surgery was 8,6 years. The mean external fixation index (EFI) was 34,3 and 30,1 day/cm for spatial frame and Ilizarov frame respectively. Mean follow-up period of 161,62 months and mean fixator period of 257 days. Amount of lengthening was 7,2 cm for Ilizarov frame, and 7,5 cm for spatial frame. Rate of callus with good morphological quality seen at consolidation was 72,4% and 50% for Ilizarov and spatial frames respectively. Two groups show similar results of complication rates in terms of pin site infection, premature fibular consolidation, regenerate fracture, plastic deformation, knee contracture. However fibular nonunion rates were higher for Ilizarov-type fixator. Conclusions. Although spatial frame with computer assistance brings easier follow-up for deformity correction, Ilizarov-type external fixator show slightly higher rates of good quality callus during consolidation for patients with achondroplasia

We carried out an MRI study of the lumbar spine in 15 patients with achondroplasia to evaluate the degree of stenosis of the canal. They were divided into asymptomatic and symptomatic groups. We measured the sagittal canal diameter, the sagittal cord diameter, the interpedicular distance at the mid-pedicle level and the cross-sectional area of the canal and spinal cord at mid-body and mid-disc levels. The MRI findings showed that in achondroplasia there was a significant difference between the groups in the cross-sectional area of the body canal at the upper lumbar levels. Patients with a narrower canal are more likely to develop symptoms of spinal stenosis than others

Although achondroplasia has been cited as the most common form of rhizomelic dwarfism, no report in the literature has given the data on the ratio of their upper and lower limb segments. We performed a paired study of 91achondroplasia patients with age and gender matched normal control group. Their upper and lower extremity radiographs were evaluated, and their radio-humeral and tibia-femoral ratios were compared. The ratios were compared using the Wilcoxon rank sum test. A p value of <0.05 was considered significant. The mean age of the patients was 15.8 years (95% confidence interval (CI), 13.1–18.6), and there were 45 males and 46 females. The radio-humeral ratio for the upper extremity of achondroplasia patients was 0.76 (95% CI, 0.75–0.76) which was significantly different from the normal control group of 0.79 (95% CI, 0.77–0.80) (p=0.001). The tibio-femoral ratio of the achondroplasia patients was 0.79 (95% CI, 0.78–0.79), which was not significantly different from the normal control group of 0.78 (95% CI, 0.77–0.79) (p=0.346). Rhizomelia is the predominant form of dwarfism in upper extremity, but not in lower extremity in achondroplasia. The functional deficits from these patients seem to come from the generalized limb shortness, and not specifically from rhizomelia

Introduction. To evaluate the results of correction of knee deformities based on deformity analysis in Achondroplasia, the commonest skeletal dysplasia as some have concomitant ligamentous deformities. Materials and Methods. Retrospective study from a prospective database (2007–2020) of achondroplasts who underwent growth modulation. Analysis of medical records with objective measurement of mechanical axis radiographs was done (Traumacad). Satisfactory alignment was defined as neutral to slightly varus (0–15 mm MAD) so that the MCL/LCL laxity is not revealed. Results. 23 patients, 41 limbs, 34 bilateral, 6 unilateral underwent multiple growth modulation procedures. 2 had valgus knees. 15 patients underwent proximal fibular epiphysiodesis in addition for LCL laxity with one isolated fibular epiphysiodesis. Mechanical axis deviation (MAD) improved or normalised in 16 patients (70%). 4 patients were still undergoing correction. 4 patients needed further surgery out of which 2 patients were over 13 years when growth modulation was attempted and 2 needed correction of ankle varus. JLCA improved/ normalised in 12 patients (75%) with evidence of indirect LCL tightening and no improvement was seen in 4. The rate of correction was MAD 0.61mm/month, LDFA 0.29°/month and MPTA 0.13°/month; expectedly lower in achondroplasia due to lower growth velocity. Conclusions. This study highlights the pathology, application of growth modulation as per deformity analysis unlike previous studies. Proximal fibular epiphysiodesis improves LCL laxity in a majority of these children and is a simple procedure compared to our published series with indirect LCL tightening with frames

Lengthening of the humerus is now an established technique. We compared the complications of humeral lengthening with those of femoral lengthening and investigated whether or not the callus formation in the humerus proceeds at a higher rate than that in the femur. A total of 24 humeral and 24 femoral lengthenings were performed on 12 patients with achondroplasia. We measured the pixel value ratio (PVR) of the lengthened area on radiographs and each radiograph was analysed for the shape, type and density of the callus. The quality of life (QOL) of the patients after humeral lengthening was compared with that prior to surgery. The complication rate per segment of humerus and femur was 0.87% and 1.37%, respectively. In the humerus the PVR was significantly higher than that of the femur. Lower limbs were associated with an increased incidence of concave, lateral and central callus shapes. Humeral lengthening had a lower complication rate than lower-limb lengthening, and QOL increased significantly after humeral lengthening. Callus formation in the humerus during the distraction period proceeded at a significantly higher rate than that in the femur. . These findings indicate that humeral lengthening has an important role in the management of patients with achondroplasia

Aim. The aim of the study was to characterise gait in patients with achondroplasia post lengthening. Patients/Materials and Methods. Full kinematic and kinetic lower limb gait analysis was performed at the Sheffield Children's Hospital gait laboratory, Sheffield, using a Vicon system (6 cameras working at 50Hz) and processed using Plug In Gait modelling software. The lengthened Achondroplasia group (n=11, mean age = 24.5 ± 6.1) had previously undergone surgical lengthening of the legs. The lengthened Achondroplasia group was compared to a control group of 11 adult normal subjects. Results. Averaged sagittal plane kinematics are shown in Figure 1. The key sagittal plane characteristics we found were increased anterior pelvic tilt (Achondroplasia mean = 22.2 ± 7.1°, normal mean = 14.2 ± 5.3°), decreased peak hip extension (Achondroplasia = 10.5 ± 11.2°, normal = −5.8 ± 5.3°), increased peak hip flexion (Achondroplasia = 49.3 ± 9.8°, normal = 40.0 ± 5.2°), and reduced knee extension in midstance (Achondroplasia = 14.0 ± 8.5°, normal = 4.4 ± 8.5°) At the ankle the mean of the lengthened Achondroplasia group lies within one standard deviation of the normal dataset throughout the gait cycle. Summary and Conclusions. Three dimensional gait analysis of people with Achondroplasia following lower limb-lengthening surgery showed characteristic Achondroplasic gait, that is: increased anterior pelvic tilt, reduced hip extension and increased hip flexion. The group of lengthened Achondroplasia participants also failed to extend the knees fully in midstance. At the ankle the sagittal plane kinematics were within one standard deviation of the normal dataset

Introduction We have reviewed the clinical outcome and complications of Monofocal and Bifocal Callotasis for lower limb lengthening in children with Achondroplasia. Methods Between August 1986 and January 1999, 57 children with Achondroplasia had lower limb lengthening. Monofocal callotasis had been carried out in 147 Segments of 44 children and bifocal callotasis in 38 segments of 17 children. Complications were noted and final outcomes recorded. Results The 29 children who completed the programme gained an average of 20 cms in height. For all patients, the mean length gained per segment was roughly nine centimetres. Average Bone Healing Index in the mono-focal lengthening group was 39.9 days/cm and in the bifocal lengthening group 33.6 days/cm. Complications were staged and graded and the average was 2.8 complications per lengthened segment. Most were pin-site related and occurred during stage of distraction. Twenty percent of the segments required further axis corrections. Most patients regained their pre-operative range of motion. Serious irreversible complications were seen in only two patients and included a physeal bar and psychological disturbances. Functional outcome analyses are planned. Conclusions Limb lengthening for short stature due to Achondroplasia can be confidently undertaken with favourable results in most cases. Bifocal lengthening is an alternative technique with quicker consolidation time

Introduction: Achondroplasia is a form of rhizomelic dwarfism. Even if patients can compensate for their short arms through the mobility in their spine during the childhood, the flexibility in their spine becomes less with aging. Because of that, as they get older they experience problems in maintaining personal hygiene especially in reaching the back. In addition putting on socks and tying their own shoes might become difficult. Methods: Inclusion criteria included any patient with a history of achondroplasia who had undergone humeral lengthening in the proximal part of the humerus (just distal to deltoid muscle insertion). Patients who had distal humeral (supracondylar) osteotomy and/or who received other than monolateral external fixator were excluded from the study. 50 humeri of 25 patients with achondroplasia were lengthened using Orthofix mono-lateral external fixator utilizing proximal humeral osteotomy. Sixteen patients were female and nine were male. Mean age was 15.4 months (range, 9.6 – 21.8). Lengthening was started at 7th day. Patients were lengthened at 1/4 turn four times a day reaching 1 mm/day. Physical therapy was performed 3 times a week. Goal of lengthening was around 10 cm or whatever length the patient could tolerate. Patients wore Sarmiento type fracture brace 4–6 weeks after the fixator was removed. Results: Mean follow-up time from surgery was 51.5 months (range, 6 – 143 months). Mean follow-up time from removal of external fixator was 44.7 months (range, 0 – 135 months). Average external fixation time was 7.3 months. In 20 humeri it was noted that the average duration of lengthening was 4.2 months (range, 3 – 5.8 months). A mean lengthening of 9.3 cm was obtained (range, 4.3 – 12.8 cm). At latest follow-up range of motion was not compromised due to lengthening. All patients had similar ROM before and after the surgery. Complications included radial nerve palsy in 8, pin tract infection in 7, fracture through regenerate in 3, premature consolidation in 1, nonunion in 1, delayed healing in 1. Radial nerve palsy recovered without intervention in one case. In others it recovered uneventfully after successful decompression. No complications at all occurred in 30 cases. Discussion: Fifty humeri of 25 patients with achondroplasia received successful humerus lengthening as part of extensive limb lengthening offered in our center. None of the patients had long term sequela, and all radial nerve palsies recovered. Patients were satisfied with the lengthening and found it easier to undergo through humerus lengthening compared to lower limb lengthening. After a mean follow-up time of almost 4 years, these patients returned back to their normal lives with optimum upper limb function with no hindrance in maintaining personal hygiene, putting on socks or tying their own shoes

Genu varum in the achondroplastic patient has a complex and multifactorial aetiology. There is little mention in the literature of the role of fibular overgrowth. Using the ratio of fibular to tibial length as a measurement of possible fibular overgrowth, we have related it to the development of genu varum. Full-length standing anteroposterior radiographs of 53 patients with achondroplasia were analysed. There were 30 skeletally-immature and 23 skeletally-mature patients. Regression analysis was performed in order to determine if there was a causal relationship between fibular overgrowth and the various indices of alignment of the lower limb. Analysis showed that the fibular to tibial length ratio had a significant correlation with the medial proximal tibial angle and the mechanical axial deviation in the skeletally-immature group. We conclude that there is a significant relationship between fibular overgrowth and the development of genu varum in the skeletally-immature achondroplastic patient

Forty-eight patients with achondroplasia and 24 with hypochondroplasia have been reviewed in order to clarify the differences between the two disorders and establish the height, body proportions and other clinical and radiological variations within each group. Some of the "classical" findings in achondroplasia are not always present, and hypochondroplasia at its most severe is indistinguishable from achondroplasia at its least severe. The frequency of spinal stenosis and neurological complications was established in an unselected group of 27 achondroplastic and 12 hypochondroplastic patients aged 10 years and over. Only three of the former were free of symptoms but only three developed serious complications (11 per cent). Measurement of radiographs of the lumbar canal did not in general correlate well with the severity of spinal stenosis symptoms, but it was found that the ratio of interpedicular distances at the first and fourth lumbar vertebrae had some value. Neurological complications were rare in patients with simple narrowing of the spinal canal or with persistence of a thoracolumbar kyphos but when these occurred together there was a high risk of serious neurological involvement

Recent studies of the fibroblast growth factor receptor 3 (FGFR3) gene have established that achondroplasia and hypochondroplasia are allelic disorders of different mutations. To determine whether the genotype could be distinguished on the basis of the phenotype, we analysed height, arm span, and skeletal radiographs from 23 patients with achondroplasia and the G380R mutation of FGFR3 and eight with hypochondroplasia and the N540K mutation. Both conditions share the classical pathological features of micromelic short stature, reduced or unchanged interpedicular distances in the lumbar spine, disproportionately long fibulae, and squared and shortened pelvic ilia. These were significantly more severe in the G380R patients than in the N540K patients. Our findings have shown a firm statistical correlation between the genotype and the phenotype, although there were a few exceptional cases in which there was phenotypic overlap between the two conditions

Background: The incidence of neurological symptoms due to spinal stenosis in patients with achondroplasia is reported to be as great as 38%. 1. These symptoms most commonly occur in the 4. th. decade and myelography and CT myelography are most commonly described in evaluation of the stenosis. Difficulty arises in localisation of stenosis in patients presenting with neurological deficit. 2. The value of MRI of the cervicomedullary junction has been reported in achondroplasia but it has not yet been evaluated in the investigation of spinal stenotic symptoms. The aim of this study was to review our experience of whole spine imaging in patients with achondroplasia that presented with symptoms and signs of neurological deficit. Methods: We retrospectively reviewed the clinical notes and radiological imaging of 10 consecutive achondroplastic patients (3F:7M, mean age 31.7 years, range 13 to 60yrs) that presented to our unit with neurological compromise between 1998 and 2003. All patients had whole spine MRI at the time of presentation. Recorded from the notes were age and sex, and whether symptom pattern was radiculopathy, claudication or paresis. All radiological levels of stenosis on MRI were documented. Results: Four patients presented with spinal paresis, four with neurogenic claudication, and two with radiculopathy. MRI confirmed that each patient had at least one region (cervical, thoracic or lumbar) of significant spinal stenosis. In six of the patients an additional region of significant stenosis was identified. All ten patients had lumbar stenosis but this was only the primary site in six of the ten. In the other four patients two had the dominant stenosis in the thoracic spine, one in the cervical spine and one at the foramen magnum – the clinical symptoms correlated with the dominant site in each of these four cases. Conclusion: MRI was a useful tool for assessment of neurological compromise in the patients with achondroplasia in our study. All ten patients had classical lumbar stenosis on MRI but this was only the dominant site of stenosis in six of the ten cases. The MRI and clinical findings need to be evaluated together to ensure correct surgical treatment

Aim: Spinal stenosis is a known entity in achondroplasia and a need for screening for the symptomatic children was identified in a tertiary limb reconstruction service. The aim of this study was to evaluate whether clinical and radiological imaging would identify the at risk group. Materials and methods: 205 achondroplastic children were treated at our service in the last 20 years. A prospective clinical screening programme for spinal stenosis which also included the MRI imaging of entire spine was however introduced only in 1996. 26 patients were available for this study. Case notes were reviewed for clinical symptoms and neurological signs. MR images were assessed for stenosis especially at Cervico medullary junction and lumbar level. Canal diameters were measured at all spinal levels from CMJ to lumbo-sacral junction. Neurosurgical interventions were recorded. An attempt was made to identify high risk factors that required surgical intervention. Results: Delayed milestones were observed in 7 patients. Positive history of back pain or radicular pain was obtained in 10 whereas 10 patients had symptoms of neurogenic claudication. Brisk reflexes and clonus were consistent findings. Severe foramen magnum narrowing was observed in 23 patients and 13 showed ‘kinking’ or ‘pinching’, suggesting severe compression. Of the 17 patients seen by neurosurgeons 6 required single or multiple surgical decompressions. Ventriculo-peritoneal shunt was inserted in 4. 5 children required CMJ decompression and one required lumbar canal decompression. There was a 7 mm difference in AP diameter measured on MRI at CMJ between the two non operated and operated groups. Female patients with delayed milestones and CMJ narrowing to less than 25 mm were identified as high risk. Conclusion: The cause of increased morbidity and mortality in young achondroplasts is attributable to severe CM compression. Sudden death can occur by acute or gradual progressive encroachment of respiratory centre at medulla oblongata. We were able to identify symptomatic patients early before developing myelomalacia and cord changes by screening all symptomatic children with achondroplasia. We propose that female gender, especially with delayed milestones as another high risk factor. We stress upon the importance of developing a nationalised selective screening programme with guidelines in specialist orthopaedic and joint multi-disciplinary Skeletal Dysplasia clinics

Two types of fracture, early and late, have been reported following limb lengthening in patients with achondroplasia (ACH) and hypochondroplasia (HCH). . We reviewed 25 patients with these conditions who underwent 72 segmental limb lengthening procedures involving the femur and/or tibia, between 2003 and 2011. Gender, age at surgery, lengthened segment, body mass index, the shape of the callus, the amount and percentage of lengthening and the healing index were evaluated to determine predictive factors for the occurrence of early (within three weeks after removal of the fixation pins) and late fracture (> three weeks after removal of the pins). The Mann‑Whitney U test and Pearson’s chi-squared test for univariate analysis and stepwise regression model for multivariate analysis were used to identify the predictive factor for each fracture. Only one patient (two tibiae) was excluded from the analysis due to excessively slow formation of the regenerate, which required supplementary measures. A total of 24 patients with 70 limbs were included in the study. There were 11 early fractures in eight patients. The shape of the callus (lateral or central callus) was the only statistical variable related to the occurrence of early fracture in univariate and multivariate analyses. Late fracture was observed in six limbs and the mean time between removal of the fixation pins and fracture was 18.3 weeks (3.3 to 38.4). Lengthening of the tibia, larger healing index, and lateral or central callus were related to the occurrence of a late fracture in univariate analysis. A multivariate analysis demonstrated that the shape of the callus was the strongest predictor for late fracture (odds ratio: 19.3, 95% confidence interval: 2.91 to 128). Lateral or central callus had a significantly larger risk of fracture than fusiform, cylindrical, or concave callus. Radiological monitoring of the shape of the callus during distraction is important to prevent early and late fracture of lengthened limbs in patients with ACH or HCH. In patients with thin callus formation, some measures to stimulate bone formation should be considered as early as possible. Cite this article: Bone Joint J 2014;96-B:1269–73

A thoracolumbar gibbus is an uncommon but potentially dangerous feature of achondroplasia. In a series of unselected South African Negro achondroplasts, nine out of 17 had an abnormality of this type. In contrast, only one girl out of 20 affected individuals of European or mixed ancestry had a gibbus. It is likely that the high frequency of this deformity in South African Negro achondroplasts is the result of the traditional practice by which an infant is carried on the mother's back, with the legs straddling her waist and the spine in flexion. Wedging on the vulnerable vertebral bodies in the Negro achondroplastic infant can probably be prevented by avoiding this custom

Lack of full extension of the elbow is a common abnormality in patients with achondroplasia. We studied 23 patients (41 elbows) clinically and radiologically. Extension of the elbow was assessed clinically and the angle of posterior bowing of the distal humerus was measured from lateral radiographs. There was limited extension of the elbow in 28 (68.3%) and the mean loss of extension was 13.1°. Posterior bowing of the humerus was seen in all elbows with a mean angle of 17.0°. There was a positive correlation between these two measurements. Posterior bowing greater than 20° caused a loss of full elbow extension. Posterior dislocation of the radial head was seen in nine elbows (22.0%). The mean loss of extension of the elbows was 28.7° which was significantly greater than that of these elbows in which the head was not dislocated (8.7°), although posterior bowing was not significantly different between these two groups (19.3° and 16.3°). Posterior bowing of the distal humerus is a principal cause of loss of extension of the elbow. Posterior dislocation of the radial head causes further limitation of movement in the more severely affected joints

Our aim is to evaluate life quality in patients with achondroplasia after lengthening. We examined 17 patients (11 men and 6 women) who finished the complete lengthening process in the 3 segments (tibia, femur, humerus) more than 3 years ago. Mean age 30.35 years(17–44). And a final height of 152.3cm (140.4–169) with an increase in the size of the tibia of 15.38cm, femur 14.91cm and humerus 9.91cm. Life quality is assessed by the SF.36 test and a specific questionnaire for low size people. The results show that the mental health component (52.2) and physical component (52.8) are similar to those of general American population. There is also a statistical correlation between the final height and better results on the Mental Health questions of SF.36 (p=0.013) and the psychological questions of the specific questionnaire (p=0.045). Achondroplasic patients after lengthening have a standard life quality and the increase of their height improves the mental health aspects of life quality

Extensive limb lengthening may be indicated in achondroplastic patients who wish to achieve a height within the normal range for their population. However, increasing the magnitude of lengthening is associated with further complications particularly adjacent joint stiffness and fractures. We studied the relationship between the magnitude of femoral lengthening and callus pattern, adjacent joint stiffness and fracture of the regenerate bone in 40 femoral lengthenings in 20 achondroplastic patients. They were divided into two groups; group A had lengthening of less than 50% and group B of more than 50% of their initial femoral length. The patterns of radiological callus formation were classified according to shape, type and features. The incidence of callus features, knee stiffness and regenerate bone fracture were analysed in the two groups. Group B was associated with an increased incidence of concave, lateral and central callus shapes, adjacent joint and stiffness and fracture. Statistically, the incidence of stiffness in adjacent joints and regenerate bone fracture was significantly associated with the magnitude of lengthening.

We suggest that careful radiological assessment of the patterns of callus formation is a useful method for the evaluation and monitoring of regenerate bone.

Introduction

The effect of lower extremity lengthening on physeal growth is still controversial. We aim to compare data of the patients who had bilateral simultaneous femur and tibia lengthening with the patients who underwent the lengthening surgery separately for the femur and tibia at the end of completed skeletal maturation in terms of the effect of physeal growth.