Staged upper and lower limb lengthening performing bilateral simultaneous surgery of the femur and tibia in achondroplastic patients

Prophylactic Intramedullary Rodding After Femoral Lengthening in Patients With Achondroplasia and Hypochondroplasia

BACKGROUND

Femoral fracture after femoral lengthening in patients with achondroplasia and hypochondroplasia is a frequent complication, occurring in up to 30%. The purpose of this study is to demonstrate the effectiveness of prophylactic intramedullary rodding in preventing this complication.

METHODS

Multicenter retrospective study involving 86 femoral lengthening procedures in 43 patients with achondroplasia or hypochondroplasia. Forty-two femora (21 patients) were prophylactically managed with intramedullary Rush rodding after external fixation removal (11 females and 10 males, mean age 14.6 years) compared with 44 femora (22 patients) without prophylactic intramedullary rodding (13 females and 9 males, mean age 15.2 years). The mean amount of lengthening in the rodding group was 13.3 cm (52.6%) with an External Fixation Index of 25.8 days/cm; in patients without rodding was 14.3 cm (61.5%) and 24.5 days/cm, respectively.

RESULTS

Seven cases (15.9%) without rodding developed fractures. Four of them required surgical correction due to displacement or shortening. Only 1 patient (2.4%) had fracture of the femur after prophylactic rodding, and surgery was not required. The incidence of femur fracture was significantly lower in the prophylactic rodding group compared with the nonrodding group (2.4% vs. 15.9%, respectively; P =0.034). There were no cases of infection or avascular necrosis.

CONCLUSIONS

Prophylactic intramedullary rodding is a safe and effective method for preventing femoral fractures after femoral lengthening in patients with achondroplasia or hypochondroplasia.

LEVEL OF EVIDENCE

Level III-a retrospective comparative study.

Vosoritide Therapy in Children with Achondroplasia: Early Experience and Practical Considerations for Clinical Practice

INTRODUCTION

Vosoritide is the first precision medical therapy approved to increase growth velocity in children with achondroplasia. Sharing early prescribing experiences across different regions could provide a framework for developing practical guidance for the real-world use of vosoritide.

METHODS

Two meetings were held to gather insight and early experience from experts in Europe, the Middle East, and the USA. The group comprised geneticists, pediatric endocrinologists, pediatricians, and orthopedic surgeons. Current practices and considerations for vosoritide were discussed, including administration practicalities, assessments, and how to manage expectations.

RESULTS

A crucial step in the management of achondroplasia is to determine if adequate multidisciplinary support is in place. Training for families is essential, including practical information on administration of vosoritide, and how to recognize and manage injection-site reactions. Advocated techniques include establishing a routine, empowering patients by allowing them to choose injection sites, and managing pain. Patients may discontinue vosoritide if they cannot tolerate daily injections or are invited to participate in a clinical trial. Clinicians in Europe and the Middle East emphasized the importance of assessing adherence to daily injections, as non-adherence may impact response and reimbursement. Protocols for monitoring patients receiving vosoritide may be influenced by regional differences in reimbursement and healthcare systems. Core assessments may include pubertal staging, anthropometry, radiography to confirm open physes, the review of adverse events, and discussion of concomitant or new medications-but timing of these assessments may also differ regionally and vary across institutions. Patients and families should be informed that response to vosoritide can vary in both magnitude and timing. Keeping families informed regarding vosoritide clinical trial data is encouraged.

CONCLUSION

The early real-world experience with vosoritide is generally positive. Sharing these insights is important to increase understanding of the practicalities of treatment with vosoritide in the clinical setting.

Results and complications of bilateral limb lengthening in achondroplasia: a retrospective analysis

Background

Achondroplasia is one of the main causes of disharmonic dwarfism. Patients with achondroplasia might have physical and psychological limitations due to their disproportionate stature. Surgical limb lengthening is the only practical option available to achieve a stature comparable to normal population range. The purpose of this study is to analyze results and complications of our lengthening protocol.

Methods

A retrospective analysis was performed on 33 patients with achondroplasia (21 females and 12 males) undergoing simultaneous bilateral tibia or femur lengthening in four surgical stages from 2017 to 2021 (46 lengthening procedures, with a total of 56 tibias and 36 femurs). For each patient, patients' characteristics and antero-posterior and lateral radiographs were obtained. The following parameters were analyzed: duration of lengthening with external fixator, amount of lengthening, complications or events that influenced outcomes and the healing index (HI).

Results

The average tibial and femoral gain was 7.9 cm and 6.9 cm, respectively. The tibiae achieved better results than the femurs (p = 0.005). Nineteen complications were reported for 92 segments (20.7%), and the variables influencing complications were: step (p = 0.002) and fixation duration (p = 0.061).

Conclusions

Bilateral parallel lower limb lengthening in four surgical steps may be a viable technique in patients with achondroplasia.

Burden and Treatment of Achondroplasia: A Systematic Literature Review

BACKGROUND

Achondroplasia is the most common form of skeletal dysplasia. Recent advances in therapeutic options have highlighted the need for understanding the burden and treatment landscape of the condition. This systematic literature review (SLR) aimed to identify health-related quality of life (HRQoL)/utilities, healthcare resource use (HCRU), costs, efficacy, safety and economic evaluation data in achondroplasia and to identify gaps in the research.

METHODS

Searches of MEDLINE, Embase, the University of York Centre for Reviews and Dissemination (CRD), the Cochrane Library and grey literature were performed. Articles were screened against pre-specified eligibility criteria by two individuals and study quality was assessed using published checklists. Additional targeted searches were conducted to identify management guidelines.

RESULTS

Fifty-nine unique studies were included. Results demonstrated a substantial HRQoL and HCRU/cost-related burden of achondroplasia on affected individuals and their families throughout their lifetimes, particularly in emotional wellbeing and hospitalisation costs and resource use. Vosoritide, growth hormone (GH) and limb lengthening all conferred benefits for height or growth velocity; however, the long-term effects of GH therapy were unclear, data for vosoritide were from a limited number of studies, and limb lengthening was associated with complications. Included management guidelines varied widely in their scope, with the first global effort to standardise achondroplasia management represented by the International Achondroplasia Consensus Statement published at the end of 2021. Current evidence gaps include a lack of utility and cost-effectiveness data for achondroplasia and its treatments.

CONCLUSIONS

This SLR provides a comprehensive overview of the current burden and treatment landscape for achondroplasia, along with areas where evidence is lacking. This review should be updated as new evidence becomes available on emerging therapies.

Lifetime impact of achondroplasia study in Europe (LIAISE): findings from a multinational observational study

BACKGROUND

Achondroplasia, caused by a pathogenic variant in the fibroblast growth factor receptor 3 gene, is the most common skeletal dysplasia. The Lifetime Impact of Achondroplasia Study in Europe (LIAISE; NCT03449368) aimed to quantify the burden of achondroplasia among individuals across a broad range of ages, including adults.

METHODS

Demographic, clinical and healthcare resource use data were collected from medical records of achondroplasia patients enrolled in 13 sites across six European countries in this retrospective, observational study. Descriptive statistics or event rates per 100 person-years were calculated and compared across age groups as well as by history of limb lengthening. Patient-reported outcomes (quality of life [QoL], pain, functional independence, work productivity and activity impairments) were evaluated using questionnaires at the time of enrolment. An exploratory analysis investigated correlations between height (z-score or centimetres) and patient-reported outcomes.

RESULTS

Overall, 186 study patients were included, with a mean age of 21.7 ± 17.3 years (range 5.0-84.4). At least one complication or surgery was reported for 94.6% and 72.0% of patients, respectively, at a rate of 66.6 and 21.5 events per 100 person-years. Diverse medical and surgical complications were reported for all ages in a bimodal distribution, occurring more frequently in the youngest and oldest age groups. A total of 40 patients had previously undergone limb lengthening (capped at 20% per the study protocol). The most frequent surgery types varied by age, in line with complication profiles. Healthcare resource use was high across all age groups, especially among the youngest and oldest individuals, and did not differ substantially according to history of limb lengthening. Compared to general population values, patients reported impaired QoL particularly for physical functioning domains. In addition, patients reported difficulty carrying out daily activities independently and pain starting in childhood. Patient height correlated with multiple patient-reported outcomes.

CONCLUSIONS

The findings of this study suggest that, across an individual's lifetime, achondroplasia is associated with multisystem complications, reduced QoL and functionality, and increased pain. These results highlight the large amount of healthcare resources that individuals with achondroplasia require throughout their lifespans and provide novel insights into current achondroplasia management practices across Europe. Trial registration ClinicalTrials.gov, NCT03449368, Submitted 14 December 2017 - prospectively registered, https://clinicaltrials.gov/ct2/show/record/NCT03449368.

Achondroplasia: Update on diagnosis, follow-up and treatment

Achondroplasia requieres multidisciplinary follow-up, with the aim of preventing and managing complications, improving the quality of life of people who suffer from it and favoring their independence and social inclusion. This review is justified by the multiple publications generated in recent years that have carried out a change in its management. Different guidelines and recommendations have been developed, among which the one made by the American Academy of Pediatrics in 2005 recently updated (2020), the Japanese guide (2020), the first European Consensus (2021) and the International Consensus on the diagnosis, approach multidisciplinary approach and management of individuals with achondroplasia throughout life (2021). However, and despite these recommendations, there is currently a great worldwide variability in the management of people with achondroplasia, with medical, functional and psychosocial consequences in patients and their families. Therefore, it is essential to integrate these recommendations into daily clinical practice, taking into account the particular situation of each health system.

The Relationship Between Limb Lengthening Rate and Callus Quality in Patients with Achondroplasia

OBJECTIVES

This study investigated the effect of the femur, tibia, and humeral lengthening rate in patients with achondroplasia and regenerated bone quality.

METHODS

The records of the patients with achondroplasia who underwent limb lengthening surgery for both upper and lower extremities between 2002 and 2019 were retrospectively reviewed. Bone formation regeneration was evaluated in each segment at anteroposterior and lateral radiographs and the callus quality was determined at the first month of the consolidation period according to Li's classification system.

RESULTS

This study included 42 (28 females and 14 males), 38 (26 females and 12 males), and 17 (11 females and 6 males) patients with bilateral femoral, bilateral tibial, and bilateral humeral lengthening. The mean lengthening rate was 0.920 ± 0.23 (range, 0.53-1.67), 0.813 ± 0.17 (range, 0.51-1.26), and 1.02 ± 0.26 (range, 0.58-150) mm/day in the femoral, tibial, humeral groups, respectively. In the femoral group, 75% femur with good morphological quality, 56.6% good morphological quality in tibial group and 55.9% good morphological quality in humeral group. Statistically significant relationships were found between femoral lengthening rate and callus quality (p < 0.001; r = 0.454). However, no significant correlation was found in the humeral and tibial groups. Moreover, the sensitivity and specificity of the lengthening rate for obtaining good morphological quality callus were 72% and 80%, respectively, with an optimum diagnostic cutoff value of 0.976 mm/day for femoral lengthening.

CONCLUSIONS

A higher-rate good morphological callus was obtained in femoral lengthening compared with tibia and humerus in patients with achondroplasia.

Two-stage Bone Lengthening With Reuse of a Single Intramedullary Telescopic Nail in Patients With Achondroplasia

BACKGROUND

Patients with achondroplasia may benefit from limb-lengthening surgery with telescopic intramedullary nails (TIMNs). However, the 5-cm maximum length of the nails used in these patients in their original design may be insufficient. The aim of this research is to analyze the outcomes and complications after reusing the same TIMN for a second consecutive 5-cm lengthening in patients with achondroplasia.

METHODS

Retrospective study of 26 bones (16 femurs and 10 tibias) in 9 patients with achondroplasia treated for bilateral 2-stage sequential lengthening reusing the same TIMN. On completion of a first stage of 5 cm of elongation, the nail was unlocked, retracted, and re-locked; a second stage of 5 cm of distraction followed. Radiologic and clinical parameters were measured preoperatively and postoperatively, and complications were recorded.

RESULTS

The median age of patients at first surgery was 13.54 (12.9 to 16.3) years; 55% were males. The median preoperative height was 121 (117.5 to 127) cm, and the median healing index was 18.12 (14.5 to 32.8) and 26.96 (23.3 to 31.6) d/cm, while time to weight bearing was 185.5 (144.8 to 308.5) and 242.5 (208.5 to 293.8) days for femurs and tibias, respectively. Major complications included 3 cases of moderate ankle equinus, 2 cases of hardware failure (failure to relengthen), 2 premature consolidations, 1 common peroneal neurapraxia, and 2 valgus deformities. Femoral procedures had significantly fewer complications than tibial interventions (7 vs. 15, P=0.03), whereas patients who underwent lengthening of both the femur and tibia did not have significantly higher complication rates (14 vs. 8, P=0.6).

CONCLUSIONS

This study analyzes lower-limb lengthening in a series of achondroplastic patients using TIMN with the novelty of nail reuse to relengthen the bone. The complication rate found is acceptable, among which, potential damage to the internal lengthening mechanism must be considered, though this complication can usually be easily resolved. Overall, nail reuse seems advisable in cases where bone elongation is indicated, and the size and design of the nail limits the extent of lengthening.

LEVEL OF EVIDENCE

Level III, retrospective comparative study, before and after intervention.

International Consensus Statement on the diagnosis, multidisciplinary management and lifelong care of individuals with achondroplasia

Achondroplasia, the most common skeletal dysplasia, is characterized by a variety of medical, functional and psychosocial challenges across the lifespan. The condition is caused by a common, recurring, gain-of-function mutation in FGFR3, the gene that encodes fibroblast growth factor receptor 3. This mutation leads to impaired endochondral ossification of the human skeleton. The clinical and radiographic hallmarks of achondroplasia make accurate diagnosis possible in most patients. However, marked variability exists in the clinical care pathways and protocols practised by clinicians who manage children and adults with this condition. A group of 55 international experts from 16 countries and 5 continents have developed consensus statements and recommendations that aim to capture the key challenges and optimal management of achondroplasia across each major life stage and sub-specialty area, using a modified Delphi process. The primary purpose of this first International Consensus Statement is to facilitate the improvement and standardization of care for children and adults with achondroplasia worldwide in order to optimize their clinical outcomes and quality of life.

Experiences of children and adolescents living with achondroplasia and their caregivers

Background

Achondroplasia, caused by a pathogenic variant in the fibroblast growth factor receptor 3 gene (FGFR3), leads to significant multisystem complications across the lifespan that may affect the health‐related quality of life (HRQoL) of individuals and families living with the condition.

Methods

The objective of this qualitative study was to describe the HRQoL of children and adolescents with achondroplasia and their caregivers. Thirty‐four caregivers and 12 adolescents from the United States and Spain participated in one of eight focus groups or completed an individual interview, which was audio‐recorded and transcribed. Thematic analysis of qualitative data was performed to identify commonly occurring themes pertaining to HRQoL.

Results

Caregivers and adolescents described challenges with physical functioning and medical complications due to achondroplasia. Key challenges included difficulties performing activities of daily living, issues of accessibility, bullying, or unwanted attention in public, and negative effects on self‐esteem. Caregivers were concerned about accessing appropriate medical care for their child, and also reported experiencing financial, relational, and emotional challenges in their families. Achondroplasia also affected individuals and their families in positive ways, including increasing empathy, receiving positive attention, and feeling supported by the achondroplasia community.

Conclusions

These findings underscore the importance of regular assessments of HRQoL and the provision of psychosocial support to affected children and families.

Characteristics of the length of the radius and ulna in children

OBJECTIVES

Congenital malformation, trauma, tumor, or metabolic disease can cause length deformity of the radius or ulna, affecting the appearance and function of the forearm. Osteotomy and lengthening with external fixation can obviously improve the length of the radius and ulna (LRU). However, the extent of lengthening required is still unclear. This study analyzed the LRU in children, to provide suggested standards for various orthopedic treatments.

METHODS

Normal LRUs were measured on X-ray images in children who came to hospital for emergency treatment, with measurements including anterior-posterior (AP) radiographs, lateral (LAT) radiographs, full LRU (total length), and LRU without the epiphysis (short length). Any cases of fracture or deformity affecting measurement were excluded. Three hundred twenty-six cases were divided into 16 groups according to age from 1 year old to 16 years old.

RESULTS

The earliest epiphyseal plate and ossification center were observed in the distal part of the radius at 1 year old, and in the proximal part at 3 years old in both boys and girls. In the ulna, at the distal end it was 6 years old in girls and 7 years old in boys, while in the proximal part ossification was observed at 9 years old in both boys and girls. The proximal epiphyseal plate of the ulna began to close on X-ray images at 12 years old in girls and 13 years in boys. LRU increased with age, and there was a strong positive correlation and consistent ratio between radius, ulna and age. In short length, the ratio of the length of radius to ulna (RLRU) ranged from 0.8941 to 0.9251 AP, from 0.8936 to 0.9375 LAT. In total length, RLRU ranged from 0.9286 to 0.9508 AP, and 0.9579 to 0.9698 LAT.

CONCLUSIONS

The length and epiphyseal ossification of the radius and ulna are associated with age. RLRU is also limited to a certain range and tends to remain stable with age. These characteristics have clinical significance for deformity correction of the forearm.

Quality of life, physical functioning, and psychosocial function among patients with achondroplasia: a targeted literature review

PURPOSE

Achondroplasia (ACH) is the most common form of skeletal dysplasia, resulting in disproportionate short stature and medical complications. We review the literature on physical functioning, psychosocial function, and quality of life (QoL) in ACH individuals compared to average stature individuals or other short stature conditions. Studies that assess the association between these outcomes and height, limb length/lengthening surgery in ACH patients are also summarized.

MATERIALS AND METHODS

PubMed/MEDLINE and Embase were searched through April 2021. Study inclusion criteria were: (1) quantitative design; (2) study population consisting solely/mainly of ACH patients; (3) reports of physical functioning, psychosocial functioning, and/or QoL. Included studies were summarized separately for pediatric and adult populations.

RESULTS

Of 1664 records identified, 23 primary studies (sample size 8-437 participants) were included. Multiple tools were used across studies, including the generic PedsQL and SF-36 and height-specific QoLISSY.

CONCLUSIONS

The literature demonstrates that ACH patients experience limitations in physical functioning and poorer QoL outcomes compared to average stature people across the life span. This appeared to be at least in part due to disproportionate short stature. Future research to better characterize QoL in ACH patients will assist clinicians to better evaluate the effectiveness of management programs including novel interventions.IMPLICATIONS FOR REHABILITATIONPatients with achondroplasia experience limitations in physical functioning and poorer quality of life throughout their life course when compared to average statured individuals.Psychosocial issues are also heightened in adults with achondroplasia compared to average statured peers but are observed less frequently in children and adolescents with achondroplasia.The overall impact that limb lengthening has on physical functioning and QoL remains unclear, although there is some evidence that greater height or upper limb length may lead to an improvement in these parameters.Rehabilitation professionals should regularly assess physical functioning, psychosocial wellbeing, and quality of life in individuals with achondroplasia using condition-specific tools.

Extensive Limb Lengthening for Achondroplasia and Hypochondroplasia

Extensive limb lengthening (ELL) was completed in 75 patients: 66 achondroplasia and 9 hypochondroplasia. The average lengthening was 27 cm for achondroplasia (12–40 cm) and 17 cm for hypochondroplasia (range 10–25 cm). There were 48 females and 27 males. Lengthening was done either by 2-segment (14 patients; both tibias and/or both femurs) or by 4-segment lengthenings (64 patients; both femurs and tibias at the same time). Most patients also had bilateral humeral lengthening. Patients had 2 or 3 lower limb lengthenings and one humeral lengthening. Lengthenings were either juvenile-onset (31), adolescent-onset (38) or adult-onset (6). The average age at final follow-up was 26 years old (range 17–43 years). There were few permanent sequelae of complications. The most serious was one paraparesis. All patients returned to activities of normal living and only one was made worse by the surgery (paraparesis). This is the first study to show that ELL can lead to an increase of height into the normal height range. Previous studies showed mean increases of height of up to 20 cm, while this study consistently showed an average increase of 30 cm (range 15–40 cm) for juvenile-onset and mean increase of 26 cm (range 15–30 cm) for adolescent-onset. This results in low normal height at skeletal maturity for males and females. The adult-onset had a mean increase of 16.8 (range 12–22 cm). This long-term follow-up study shows that ELL can be done safely even with large lengthenings and that 4-segment lengthening may offer advantages over 2-segment lengthening. While all but the more recent cases were performed using external fixation, implantable limb lengthening promises to be an excellent alternative and perhaps an improvement.

Improving the accuracy of patient positioning for long-leg radiographs using a Taylor Spatial Frame mounted rotation rod

INTRODUCTION

Long-leg radiographs are used to plan and supervise the correction of bone deformity in patients treated with the Taylor Spatial Frame (TSF). Often radiographs are performed with malpositioning of the limb leading to wrong alignment measurements. The aim of this retrospective study was to show the usefulness of a simple device which might enhance the reproducibility of limb rotation on long-leg radiographs.

MATERIALS AND METHODS

We included 20 consecutive patients with TSF treatment and at least three long-leg radiographs (4.9 ± 1.3). Eight out of 20 patients received radiographs with the help of a rotation rod (device with two clamps and a carbon tube). It is placed at the most frontal tab of the reference ring while conducting the radiograph. By this means, limb rotation can be controlled. To show the usefulness of this device, two observers measured the relation of the distances between the middle of the reference ring to the medial and lateral fourth hole on the reference ring (TSF-RR). The standard deviation and range of the TSF-RR of all radiographs for each patient was calculated and compared between patients without and with the rotation rod.

RESULTS

The standard deviations of TSF-RR in patients without the rotation rod was significantly higher compared to patients with rotation rod (observer 1: p = 0.0228, observer 2: p = 0.0038). Also, the range of the TSF-RR within one patient is significant higher (observer 1: p = 0.0279, observer 2: p = 0.0038) in patients without the rotation rod compared to patients with the rotation rod.

CONCLUSIONS

The variability of rotation on radiographs was lower with the rotation rod. Therefore, more reproducible and better comparable radiographs can be conducted. Radiologic exposure might be reduced as repetition of wrongly positioned limbs on radiographs are less frequent.

Birth prevalence of achondroplasia: A systematic literature review and meta-analysis

Achondroplasia is a genetic disorder that results in disproportionate short stature. The true prevalence of achondroplasia is unknown as estimates vary widely. This systematic literature review and meta‐analysis was conducted to better estimate worldwide achondroplasia birth prevalence. PubMed, Embase, Scielo, and Google Scholar were searched, complemented by manual searching, for peer‐reviewed articles published between 1950 and 2019. Eligible articles were identified by two independent researchers using predefined selection criteria. Birth prevalence estimates were extracted for analysis, and the quality of evidence was assessed. A meta‐analysis using a quality effects approach based on the inverse variance fixed effect model was conducted. The search identified 955 unique articles, of which 52 were eligible and included. Based on the meta‐analysis, the worldwide birth prevalence of achondroplasia was estimated to be 4.6 per 100,000. Substantial regional variation was observed with a considerably higher birth prevalence reported in North Africa and the Middle East compared to other regions, particularly Europe and the Americas. Higher birth prevalence was also reported in specialized care settings. Significant heterogeneity (Higgins I² of 84.3) was present and some indication of publication bias was detected, based on visual asymmetry of the Doi plot with a Furuya‐Kanamori index of 2.73. Analysis of pooled data from the current literature yields a worldwide achondroplasia birth prevalence of approximately 4.6 per 100,000, with considerable regional variation. Careful interpretation of these findings is advised as included studies are of broadly varying methodological quality.