Predictors of low and very low bone mineral density in long-term childhood acute lymphoblastic leukemia survivors: Toward personalized risk prediction

BACKGROUND

Cohorts of childhood acute lymphoblastic leukemia (cALL) survivors reaching adulthood are increasing. Approximately 30% of survivors meet criteria for low bone mineral density (BMD) 10 years after diagnosis. We investigated risk factors for low BMD in long-term cALL survivors.

METHODS

We recruited 245 cALL survivors from the PETALE (Prévenir les effets tardifs des traitements de la leucémie aiguë lymphoblastique chez l'enfant) cohort, who were treated with the Dana Farber Cancer Institute protocols, did not experience disease relapse or hematopoietic stem cell transplants, and presented with more than 5 years of event-free survival. Median time since diagnosis was 15.1 years.

RESULTS

Prevalence of low DXA-derived BMD (Z-score ≤-1) ranged between 21.9% and 25.3%, depending on site (lumbar spine (LS-BMD), femoral neck (FN-BMD), and total body (TB-BMD), and between 3.7% and 5.8% for very low BMD (Z-score ≤-2). Males had a higher prevalence of low BMD than females for all three outcomes (26%-32% vs. 18%-21%), and male sex acted as a significant risk factor for low BMD in all models. Treatment-related factors such as cumulative glucocorticoid (GC) doses and cranial radiation therapy (CRT) were associated with lower BMDs in the full cohort and in females at the FN-BMD site.

CONCLUSION

Low and very low BMD is more prevalent in male cALL survivors. Male sex, high cumulative GC doses, CRT, risk group, and low body mass index (BMI) were identified as risk factors for low BMD. A longer follow-up of BMD through time in these survivors is needed to establish if low BMD will translate into a higher risk for fragility fractures through adulthood.

Delivering a Home-Based Exercise Program to Youth With Osteogenesis Imperfecta: Protocol for a Comparative-Approach Study

BACKGROUND

Osteogenesis imperfecta (OI) is a rare bone fragility disorder associated with muscle weakness. Individuals with OI may therefore benefit from exercise interventions aiming to improve muscle and bone strength. Given the rarity of OI, many patients do not have access to exercise specialists who are familiar with the disorder. As such, telemedicine, the provision of health care through technology to provide care at a distance, may be well suited for this population.

OBJECTIVE

The main objectives are (1) to investigate the feasibility and cost-effectiveness of 2 telemedicine approaches for the delivery of an exercise intervention for youth with OI and (2) to assess the impact of the exercise intervention on muscle function and cardiopulmonary fitness in youth with OI.

METHODS

Patients with OI type I (the mildest form of OI; n=12, aged 12-16 years) from a pediatric orthopedic tertiary hospital will be randomized to receive a 12-week remote exercise intervention in either (1) a supervised group (n=6), monitored every session, or (2) a follow-up group (n=6), receiving monthly progress update appointments. Participants will undergo the following pre- and postintervention evaluations: sit-to-stand test, push-up test, sit-up test, single-legged balance test, and a heel-rise test. Both groups will be given the same 12-week exercise regimen, which includes cardiovascular, resistance, and flexibility training. For each exercise training session involving the supervised group, a kinesiologist will provide instructions to participants through live video sessions using a teleconferencing application. On the other hand, the follow-up group will discuss their progress with the kinesiologist every 4 weeks over a teleconferencing video call. Feasibility will be assessed by recruitment, adherence, and completion rates. A cost-effectiveness analysis of both approaches will be computed. Changes in muscle function and cardiopulmonary fitness will be examined between the 2 groups, pre- and postintervention.

RESULTS

It is anticipated that the supervised group will have higher adherence and completion rates compared to the follow-up group, which may be associated with greater physiological benefits; however, it may not be as cost-effective compared to the follow-up approach.

CONCLUSIONS

By determining the most feasible telemedicine approach, this study may serve as a basis for providing increased access to specialized adjunct therapies for individuals with rare disorders.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/40262.

The Design, Development, and Usability Testing of an eHealth Program for Youths With Osteogenesis Imperfecta: Protocol for a 2-Phase User-Centered Mixed Methods Study

BACKGROUND

Innovative approaches are needed to address the self-management needs of youths with osteogenesis imperfecta (OI) transitioning into adult-oriented health care systems. Using a sequentially phased research approach, the goal is to design, develop, and test the usability of an innovative eHealth program called "Teens Taking Charge: Managing OI Online," hereafter named "Teens OI." This program seeks to optimize self-management, facilitate a successful transition to adult care, and address a critical gap in the quality of care for youths with OI.

OBJECTIVE

The study objectives are to (1) design and develop an English and French version of the Teens OI and (2) test the usability of the Teens OI in terms of efficiency, effectiveness, and satisfaction from the perspectives of youths with OI and their parents.

METHODS

A user-centered design is presently in progress to design and develop Teens OI. A "Website Design and Development Council" (ie, Council) has been convened, with 20 youths and parent dyads recruited and global experts surveyed at an international meeting. With unanimous support from the Council, usability testing of the Teens OI will ensue in 4 iterative cycles with 32 youth-parent dyads. All sociodemographic and usability metrics will be descriptively analyzed. All recorded interview and focus group data are analyzed using content analysis techniques involving an iterative process of data reduction, data display, conclusion drawing, and verification.

RESULTS

As of December 2022, an 8-person, interdisciplinary Teens OI council, comprising 4 health care professionals, 3 youths and young adults with OI, and 1 parent, has been convened to oversee the design and development of Teens OI. Two cycles of interviews have been conducted with 10 youths with OI with or without their parents (n=6) from December 2021 to September 2022. Data analysis has been in progress since April 2022. Aim 2 is ethically approved and will commence following the completion of content development, expected by late July 2023. Preliminary analysis indicates that the following topics need to be prioritized for the youths: mental health, pain, accessibility, medical care, education, community, and parental care.

CONCLUSIONS

The proposed study will design and develop a self-management and transitional care program for youths with OI in partnership with patients, caregivers, and health care professionals. This study leverages youths' openness to adopt eHealth technologies to meet their needs and has the potential to actively engage them to autonomously manage their lifelong conditions, and facilitate a successful transition to adult health care. Finally, the proposed study will also address a critical gap in the quality of care and the growing concern that the OI population transitioning from pediatric to adult care is at risk of various adverse events associated with the transition.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/47524.

Measurement Repeatability and Reproducibility of Virtual Goniometry of a Set of Acquired Images in Youths with Arthrogryposis Multiplex Congenita

OBJECTIVES

To evaluate the intra-rater repeatability and the inter-rater reproducibility of using a virtual goniometer to measure upper and lower extremity joint range of motion (ROM) in youths with arthrogryposis multiplex congenita (AMC).

METHODS

Youths presenting with AMC aged 8 to 21 years old were recruited. ROM of the upper and lower limbs were assessed remotely during a teleassessment on a video-conferencing platform. Screen captures were taken and ROM were measured by two raters, two-weeks apart, using a virtual goniometer. Intraclass correlation coefficient (ICC) and associated 95% confidence interval (CI) were calculated to assess intra-and inter-rater repeatability and reproducibility.

RESULTS

Nine participants were included with a median age of 15.9 years (range: 11.3 to 20.8 years). The overall intra-rater ICC was 0.997 (95% CI:0.996 to 0.997) for the first rater and 0.993 (95% CI:0.992 to 0.994) for the second rater. The inter-rater ICC ranged from 0.410 (95% CI:-0.392; 0.753) for forearm pronation to 0.998 (95% CI:0.996; 0.999) for elbow flexion.

CONCLUSIONS

Results of the current study suggest that virtual goniometry is reproducible and repeatable for the ROM of most joints. Future studies should evaluate procedural reliability and validity of the proposed method for youth with complex conditions.

Tendon properties in a mouse model of severe osteogenesis imperfecta

PURPOSE/AIM OF THE STUDY

Osteogenesis imperfecta is a heritable bone disorder that is usually caused by mutations in collagen type I encoding genes. The impact of such mutations on tendons, a structure with high collagen type I content, remains largely unexplored. We hypothesized that tendon properties are abnormal in the context of a mutation affecting collagen type I. The main purpose of the study was to assess the anatomical, mechanical, and material tendon properties of Col1a1^Jrt/+ mice, a model of severe dominant OI.

MATERIALS AND METHODS

The Flexor Digitorum Longus (FDL) tendon of Col1a1^Jrt/+ mice and wild-type littermates (WT) was assessed with in vitro mechanical testing.

RESULTS

The results showed that width and thickness of FDL tendons were about 40% larger in WT (p < 0.01) than in Col1a1^Jrt/+ mice, whereas the cross-sectional area was 138% larger (p < 0.001). The stiffness, peak- and yield-force were between 160% and 194% higher in WT vs. Col1a1^Jrt/+ mice. The material properties did not show significant differences between mouse strains with differences <15% between WT and Col1a1^Jrt/+ (p > 0.05). Analysis of the Achilles tendon collagen showed no difference between mice strains for the content but collagen solubility in acetic acid was 66% higher in WT than in Col1a1^Jrt/+ (p < 0.001).

CONCLUSIONS

This study shows that the FDL tendon of Col1a1^Jrt/+ mice has reduced mechanical properties but apparently normal material properties. It remains unclear whether the tendon phenotype of Col1a1^Jrt/+ mice is secondary to muscle weakness or a direct effect of the Col1a1 mutation or a combination of both.

Limited evidence for graft selection in pediatric ACL reconstruction: a narrative review

Anterior cruciate ligament reconstruction is the preferred treatment to anterior cruciate ligament injury. With the increase in anterior cruciate ligament injuries in both adults and skeletally immature patients comes the need for individualized anterior cruciate ligament reconstruction graft selection whether it is the type of graft (auto vs. allograft) or the harvesting site (hamstrings, iliotibial band, quadriceps, patella). Several factors need to be considered preoperatively in order to optimize the patients’ recovery and restore anterior cruciate ligament strength and function. These include age and bone maturity, preoperative knee flexor/extensor strength, sport participation, patient’s needs and anatomical characteristics. This paper aims at bringing evidence supporting the use of a personalized approach in graft selection for faster and more efficient return to sport and propose a theoretical framework to support the approach.

Quadriceps and Hamstring Strength in Adolescents 6 Months After ACL Reconstruction With Femoral Nerve Block, Adductor Canal Block, or No Nerve Block

Background:

Femoral nerve block (FNB) and adductor canal block (ACB) have been used increasingly for pain control during anterior cruciate ligament (ACL) reconstruction in adolescent patients. However, recent evidence suggests that the use of FNB may affect quadriceps strength recovery 6 months after surgery.

Purpose/Hypothesis:

To compare postoperative isokinetic strength in adolescents who received FNB, ACB, or no block for perioperative analgesia during ACL reconstruction. We anticipated lower postoperative quadriceps and hamstring isokinetic deficits in adolescents who received FNB as compared with ACB.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Patients were included in the study if they had undergone hamstring tendon autograft ACL reconstruction by a single surgeon from July 2008 to January 2018 and if they underwent isokinetic muscle testing at 4 to 8 months postoperatively. The participants were divided into 3 groups (no block, FNB, and ACB), and we compared the deficit in percentages between the affected and unaffected limbs as calculated from the isokinetic quadriceps and hamstring strength testing at 60 and 180 deg/s. Between-group analysis was performed using analysis of variance, with an alpha of .05.

Results:

A total of 98 participants were included in the analysis (31 no block, 36 FNB, and 31 ACB). The mean ± SD age of the patients was 15.26 ± 1.15, 15.50 ± 1.42, and 15.71 ± 1.44, for no block, FNB, and ACB, respectively. At 5.61 months postoperatively, there was no significant difference across the 3 groups in isokinetic quadriceps deficits (P ≥ .99), and the only significant difference in isokinetic hamstring deficit was observed for peak flexion at 180 deg/s, in which the ACB group had lower peak torque than the FNB group (–9.80% ± 3.48% vs 2.37% ± 3.23%; P = .035). The ratio of participants with a deficit exceeding 15% did not differ significantly among the 3 groups.

Conclusion:

Contrary to previous research, our findings indicate only minimal difference in quadriceps strength among the 3 types of perioperative analgesia in adolescents approximately 6 months after ACL reconstruction. The only significant strength deficit was seen in the hamstrings of patients receiving ACB at peak flexion as compared with those receiving FNB.

Using Telerehabilitation to Deliver a Home Exercise Program to Youth With Arthrogryposis: Single Cohort Pilot Study

BACKGROUND

Arthrogryposis multiplex congenita (AMC) is characterized by joint contractures and muscle weakness, which limit daily activities. Youths with AMC require frequent physical therapeutic follow-ups to limit the recurrence of contractures and maintain range of motion (ROM) and muscle strength; however, access to specialized care may be limited because of geographical distance. Telerehabilitation can offer a potential solution for delivering frequent follow-ups for youth with AMC, but research on the use of telerehabilitation in children with musculoskeletal disorders is scarce.

OBJECTIVE

The study aims to evaluate the feasibility of delivering a home exercise program (HEP) by using telerehabilitation for youth with AMC. We also aim to explore the effectiveness of the HEP as a secondary aim.

METHODS

Youths aged between 8 and 21 years with AMC were recruited at the Shriners Hospitals for Children-Canada. The participants completed baseline and post-HEP questionnaires (the Physical Activity Questionnaire for Adolescents, Pediatrics Outcomes Data Collection Instrument, and Adolescent and Pediatric Pain Tool), and clinicians assessed their active ROM using a virtual goniometer. Clinicians used the Goal Attainment Scale with the participants to identify individualized goals to develop a 12-week HEP and assess the achievement of these goals. Follow-ups were conducted every 3 weeks to adjust the HEP. Data on withdrawal rates and compliance to the HEP and follow-ups were collected to assess the feasibility of this approach. The interrater reliability of using a virtual goniometer was assessed using the intraclass correlation coefficient and associated 95% CI. Nonparametric tests were used to evaluate feasibility and explore the effectiveness of the HEP.

RESULTS

Of the 11 youths who were recruited, 7 (median age: 16.9 years) completed the HEP. Of the 47 appointments scheduled, 5 had to be rescheduled in ≤24 hours. The participants performed their HEP 2.04 times per week (95% CI 1.25-4.08) and reported good satisfaction with the approach. A general intraclass correlation coefficient of 0.985 (95% CI 0.980-0.989) was found for the web-based ROM measurement. Individualized goals were related to pain management; endurance in writing, standing, or walking; sports; and daily activities. In total, 12 of the 15 goals set with the participants were achieved. Statistically significant improvements were observed in the pain and comfort domain of the Pediatrics Outcomes Data Collection Instrument (preintervention: median 71; 95% CI 34-100; postintervention: median 85; 95% CI 49-100; P=.08) and Physical Activity Questionnaire for Adolescents (preintervention: median 1.62; 95% CI 1.00-2.82; postintervention: median 2.32; 95% CI 1.00-3.45; P=.046).

CONCLUSIONS

The remote delivery of an HEP for youth with AMC is feasible. Promising results were found for the effectiveness of the HEP in helping youths with AMC to achieve their goals. The next step will be to assess the effectiveness of this exercise intervention in a randomized controlled trial.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

RR2-10.2196/18688.

Home-Based Telehealth Exercise Intervention in Early-On Survivors of Childhood Acute Lymphoblastic Leukemia: Feasibility Study

Background

Acute lymphoblastic leukemia is the most common type of pediatric cancer. Acute lymphoblastic leukemia causes an altered bone mineral homeostasis state, which can contribute to osteopenia, and bone fractures, most commonly vertebral fractures. With the increasing number of childhood cancer survivors, late adverse effects such as musculoskeletal comorbidities are often reported and are further influenced by inactive lifestyle habits. Physical activity has been shown to increase the mechanical workload of the bone, mitigating bone impairment in other cancer-specific populations.

Objective

This interventional pilot study aims to investigate the use of telehealth to deliver a home-based exercise intervention for early-on survivors of bone marrow–related hematological malignancies and to assess its impact on survivors’ musculoskeletal and functional health.

Methods

We aimed to recruit a group of 12 early-on survivors of acute lymphoblastic leukemia, within 6 months to 5 years of treatment, to participate in and complete the proposed telehealth intervention with a parent. The 16-week intervention included 40 potential home-based physical activity interventions supervised by a kinesiologist through a telehealth internet platform, with monthly progression. Patients were recruited to the cohort if they were able to participate in the intervention during the first month (minimum 12 weeks of intervention). Evaluation before and after the intervention protocol highlighted differences in functional capacities and musculoskeletal health of patients using mechanography, peripheral quantitative computed tomography, 6-minute walk test, and grip force test.

Results

The recruitment rate for the intervention was low (12/57, 21% of contacted patients). Of 12 patients, 3 were excluded (1=relapse, 1=failure to meet technical requirements, and 1=abandoned). The 9 patients who completed the intervention (6 girls; mean age 10.93, SD 2.83 years; mean BMI 21.58, SD 6.55 kg/m²; mean time since treatment completion 36.67, SD 16.37 months) had a mean adherence of 89% and a completion rate of 75%. In addition, these patients showed functional improvements in lower limb muscle force and power as well as in the 6-minute walk test distance. Participants also showed improved bone health after the intervention on the following parameters: bone mineral content, stress-strain index, total and cortical cross-sectional area at the 14% site (P=.03, P=.01, P=.01, and P=.001, respectively) and 38% site of the tibia (P=.003, P=.04, P=.001, and P=.003, respectively).

Conclusions

High adherence and participation rates suggest that telehealth is a feasible method to deliver exercise interventions to young early-on survivors of acute lymphoblastic leukemia. The proposed intervention seems promising in providing benefits to patients’ functional performance and bone health, but a large-scale study is needed to confirm this assumption.

Patient and Parent Experiences with Group Telerehabilitation for Child Survivors of Acute Lymphoblastic Leukemia

BACKGROUND

Acute Lymphoblastic Leukemia (ALL) is the most common pediatric cancer. ALL and its treatment cause altered bone-mineral homeostasis, which can contribute to musculoskeletal late adverse effects (LAEs). With the increasing number of childhood cancer survivors, LAEs are reported often, and are aggravated by inactive lifestyles. A telerehabilitation program is proposed to strengthen the muscle-bone complex and prevent future impairment.

OBJECTIVE

This study aimed to explore and better understand patient and parent experience of a telerehabilitation program after completion of ALL treatment.

METHODS

ALL survivors (n = 12), 75% girls, 7.9 to 14.7 years old, within six months to five years of treatment, were recruited to participate in the proposed study, along with a parent. The 16-week group program included 40 potential home-based physical activities, with monthly progression, supervised by a kinesiologist, through an online telerehabilitation platform. Patients could be included in the study if they joined during the first month of intervention of their group (minimum 12 weeks of intervention). A semi-structured post-intervention interview was conducted with the patients and their parent during the final assessment, along with a review of the kinesiologist's clinical notes, to obtain a portrait of the participants' experience with the telerehabilitation program. Overarching themes were identified by one author and confirmed by two senior authors before extracting the various aspects of each theme.

RESULTS

Of the 12 patients recruited, three were excluded from the analysis because they did not complete the minimum 12 weeks of intervention (one = relapse, one = failure to meet technical requirements, and one = abandoned due to parent's disinterest). The nine patients who completed the program (six girls; 10.93 ± 2.83 years) had a mean adherence of 89%. The overarching themes identified were the program modalities (group approach with patient-parent paired training, supervised by a kinesiologist), the telerehabilitation system, the participants' perception of the benefits, and recommendations and suggestions from the families. Both patients and parents expressed very high satisfaction with the program and perceived benefits.

CONCLUSION

Participants appreciated the program and reported they would all recommend it to other families in similar situations. The telerehabilitation method of service delivery was perceived by some as decisive in choosing to participate, while the supervision and intra- and inter-family interactions were the motivating factors that were key to program adherence.

Muscle-bone properties after prolonged voluntary wheel running in a mouse model of dominant severe osteogenesis imperfecta

OBJECTIVE

The objective of the current study is to assess the effect of a seven-week voluntary wheel running intervention on muscles and bones properties in a mouse model mimicking dominant severe osteogenesis imperfecta (OI).

METHODS

Female wild-type (WT) and OI (Col1a1^Jrt/+) mice either performed voluntarily wheel-running exercise for 7-weeks or remained sedentary. Running distance and speed, forelimb grip strength, isolated muscle force and fatigability as well as bone morphology and mechanical properties were assessed.

RESULTS

We demonstrate that female WT and OI mice voluntarily performed exercise, although OI mice exercised less than WT littermates. The exercise regimen increased soleus muscle masses in WT and OI but increased relative grip strength in WT mice only. Specific muscle force and fatigability were similar between WT and OI mice and did not improve with exercise. Furthermore, the exercise regimen did not improve the femoral architectural and biomechanical properties in OI mice.

CONCLUSION

Our study suggests that voluntary wheel running is not appropriate to assess the effects of exercise in a mouse model of OI. Findings from exercising OI mice model studies may not necessarily be transferable to humans.

A Telerehabilitation Intervention for Youths With Arthrogryposis Multiplex Congenita: Protocol for a Pilot Study

Background

Arthrogryposis multiplex congenita (AMC) is characterized by joint contractures present in at least two body areas. In addition to these contractures, individuals with AMC can have decreased muscle mass, leading to limitations in activities of daily living. Exercise has the potential to maintain or improve the range of motion and muscle strength. However, this type of intervention necessitates frequent follow ups that are currently difficult to provide for youths with AMC because they often live far from a specialized hospital. To overcome this distance challenge, telecommunication technologies can be used to deliver rehabilitation remotely, which is called telerehabilitation. The study protocol for one such type of rehabilitation will be presented in this paper.

Objective

This pilot study aims to (1) evaluate the feasibility of using telerehabilitation to provide a home exercise program for youths with AMC, and (2) assess the effectiveness of a home exercise program.

Methods

A total of 10 youths aged 8-21 years with AMC will be recruited. The intervention consists of a 12-week individualized home-based exercise program delivered remotely using telerehabilitation. At baseline, youths will complete the Physical Activity Questionnaire for Adolescents and the Pediatrics Outcomes Data Collection Instrument to assess pain, function, and level of physical activity. During the first telerehabilitation meeting, the rehabilitation therapists will measure range of motion using a virtual goniometer and assess the youth’s functional level. The therapists will then use the Goal Attainment Scale to set objectives and develop the individualized intervention. Follow ups will occur every 3 weeks to make sure exercises are performed safely and to progress the exercises when needed. At the end of the 12-week intervention, rehabilitation therapists will re-evaluate the youth using the same outcome measures as the initial evaluation. The youths will be asked to complete the same questionnaires, with the addition of questions about their satisfaction regarding the intervention. Nonparametric and descriptive statistics will be used to evaluate the feasibility and effectiveness.

Results

Ethics approval was obtained in October 2018. Recruitment and data collection started in January 2019 and was completed in May 2020.

Conclusions

This pilot study will help us learn how a large-scale project may work in practice to improve outcomes in physical activity, pain, and function, and goal attainment among youths with AMC, thus informing a future clinical trial.

International Registered Report Identifier (IRRID)

DERR1-10.2196/18688

Musculoskeletal phenotype in two unrelated individuals with a recurrent nonsense variant in SGMS2

Heterozygous mutations in the gene encoding the sphingomyelin synthase 2, SGMS2, have recently been linked to childhood-onset osteoporosis and skeletal dysplasia. One nonsense variant at position c.148C>T (p.Arg50*) has been associated with mild bone fragility with or without cranial sclerosis. Here we assessed the effect of the SGMS2 p.Arg50* variant in two unrelated probands with childhood-onset osteoporosis and their unaffected family members. We found that the p.Arg50* variant was associated with phenotypic variability, ranging from absence of a bone phenotype to severe vertebral compression fractures and low lumbar spine areal bone mineral density (BMD) as measured by dual energy x-ray absorptiometry. Peripheral quantitative computed tomography of the radius and tibia in the two probands revealed low cortical volumetric BMD and reduced cortical thickness. In addition, both probands were obese and suffered from muscle function deficits compared to sex- and age-matched controls. Long-term bisphosphonate treatment was associated with reshaping of previously compressed vertebral bodies.

Clinical manifestations of osteogenesis imperfecta in adulthood: An integrative review of quantitative studies and case reports

Osteogenesis imperfecta (OI) is a rare genetic disorder of the bones caused by a mutation in Type I collagen genes. As adults with OI are aging, medical concerns secondary to OI may arise. This integrative review sought to review, appraise, and synthesize the clinical manifestations faced by adults with OI. Four electronic bibliographic databases were searched. Published quantitative, qualitative, and mixed-methods studies, as well as case reports from 2000 to March 2019, addressing a clinical manifestation in adulthood, were reviewed. Eligible studies and case reports were subsequently appraised using the Mixed Methods Appraisal Tool and Case Report Checklist, respectively. Twenty quantitative studies and 88 case reports were included for review regardless of the varying methodological quality score. These studies collectively included 2,510 adults with different OI types. Several clinical manifestations were studied, and included: hearing loss, cardiac diseases, pregnancy complications, cerebrovascular manifestations, musculoskeletal manifestations, respiratory manifestations, vision impairment, and other clinical manifestations. Increased awareness may optimize prevention, treatment, and follow-up. Opportunities to enhance the methodological quality of research including better design and methodology, multisite collaborations, and larger and diverse sampling will optimize the generalizability and transferability of findings.

Muscle and joint function in children living with arthrogryposis multiplex congenita: A scoping review

Arthrogryposis multiplex congenita (AMC) is characterized by congenital joint contractures present in two or more body areas. Lack of fetal movement is the underlying cause of AMC, which can lead to abnormal connective tissue surrounding the joint resulting in stiffness and muscle atrophy. Treatment aims at improving function and mobility through surgical and/or conservative interventions. A scoping review was conducted to explore the existing knowledge of the evaluation and treatment of muscle and joint function in children with AMC. Three search engines were included and identified 1,271 articles. Eighty-seven studies met the selection criteria and were included in this review. All included studies focused on joints, 30 of which also assessed the muscle. Assessment most often included the position of the contractures (n = 72), as well as range of motion (n = 66). Interventions to improve muscle and joint function were reported in 82 of the 87 papers and included surgery (n = 70) and conservative interventions (n = 74) with bony surgery (i.e., osteotomy) the most common surgery and rehabilitation the most common conservative intervention. Recurrences of contractures were mentioned in 46 of the 68 studies providing a follow-up. Future studies should use validated measures to assess muscle and joint function, and conservative interventions should be described in greater detail and to include a longer follow-up.

Identification of a single-nucleotide polymorphism within CDH2 gene associated with bone morbidity in childhood acute lymphoblastic leukemia survivors

Aim: To identify genetic markers associated with late treatment-related skeletal morbidity in survivors of childhood acute lymphoblastic leukemia (ALL). Patients & methods: To this end, we measured the association between reduction in bone mineral density or vertebral fractures prevalence and variants from 1039 genes derived through whole exome sequencing in 242 childhood ALL survivors. Top-ranking variants were confirmed through genotyping, and further explored with stratified analyses and multivariable models. Results: The minor allele of rs1944294 in CDH2 gene was associated with bone geometrical parameter, trabecular cross-sectional area (p = 0.001). The association was modulated by radiation therapy (p = 0.001) and post-treatment time (p = 0.0002). Conclusion: The variant in CDH2 gene is a potential novel risk factor of bone morbidity in survivors of childhood ALL.

Identification of genetic variants associated with skeletal muscle function deficit in childhood acute lymphoblastic leukemia survivors

Background: Although 80% of childhood acute lymphoblastic leukemia (ALL) cases are cured with current treatment protocols, exposure to chemotherapeutics or radiation therapy during a vulnerable period of child development has been associated with a high frequency of late adverse effects (LAE). Previous observations suggest important skeletal muscle size, density and function deficits in ALL survivors.

Purpose: Given that only a fraction of all patients will suffer from this particular complication, we investigated whether it could be predicted by genetic markers. 

Patients and methods: We analysed associations between skeletal muscle force (Fmax) and power (Pmax) and germline genetic variants from 1039 genes derived through whole-exome sequencing. Top-ranking association signals retained after correction for multiple testing were confirmed through genotyping, and further analysed through stratified analyses and multivariate models. 

Results: Our results show that skeletal muscle function deficit is associated with two common single nucleotide polymorphisms (SNPs) (rs2001616DUOX2, P=0.0002 (Pmax) and rs41270041ADAMTS4, P=0.02 (Fmax)) and two rare ones located in the ALOX15 gene (P=0.001 (Pmax)). These associations were further modulated by sex, body mass index and risk groups, which reflected glucocorticoid dose and radiation therapy (P≤0.02). 

Conclusion: Occurrence of muscle function deficit in childhood ALL is thus strongly modulated by variations in the DUOX2, ADAMTS4 and ALOX15 genes, which could lead to personalized prevention strategies in childhood ALL survivors.

Incidence of knee height asymmetry in a paediatric population of corrected leg length discrepancy: a retrospective chart review study

PURPOSE

The purpose of the study is to provide a methodology to quantify knee height asymmetry (KHA) and to establish the incidence of knee height asymmetry in a patient population visiting the limb length discrepancy clinic in a paediatric-orthopaedic hospital centre.

METHOD

A retrospective chart review was performed on all patients who attended the limb length discrepancy clinic and underwent corrective surgery at the Shriners Hospital for Children-Canada from December 2009 to December 2015. Full-standing anteroposterior radiographs were used to measure pre- and post-surgery limb length discrepancy and knee height asymmetry for 52 individuals included in the study.

RESULTS

Sixty-seven percent of the studied population had a KHA of 20 mm or less, 25% had a KHA between 20 and 40 mm, and 8% had a KHA of over 40 mm. The average KHA preoperatively for all 52 individuals was 17 ± 14 mm (range 0-59 mm), which represents roughly 2.5% of total limb length. There was a 3-mm non-significant reduction in KHA size between pre-and post-operative states (p = 0.22).

CONCLUSION

The current study provides a method to quantify knee height asymmetry. Using this method, it was shown that knee height asymmetry is frequent in youth with limb length discrepancy in both pre- and post-corrective surgery states. The relatively high incidence of knee height asymmetry highlights the importance to investigate the impact of knee height asymmetry in youth living with a limb length discrepancy.

Muscle-Bone Interactions in Pediatric Bone Diseases

PURPOSE

Here, we review the skeletal effects of pediatric muscle disorders as well as muscle impairment in pediatric bone disorders.

RECENT FINDINGS

When starting in utero, muscle disorders can lead to congenital multiple contractures. Pediatric-onset muscle weakness such as cerebral palsy, Duchenne muscular dystrophy, spinal muscular atrophy, or spina bifida typically are associated with small diameter of long-bone shafts, low density of metaphyseal bone, and increased fracture incidence in the lower extremities, in particular, the distal femur. Primary bone diseases can affect muscles through generic mechanisms, such as decreased physical activity or in disease-specific ways. For example, the collagen defect underlying the bone fragility of osteogenesis imperfecta may also affect muscle force generation or transmission. Transforming growth factor beta released from bone in Camurati Engelman disease may decrease muscle function.

FUTURE DIRECTIONS

Considering muscle-bone interactions does not only contribute to the understanding of musculoskeletal disorders but also can identify new targets for therapeutic interventions.

Muscle Function in Osteogenesis Imperfecta Type IV

Results of previous studies suggest that children and adolescents with osteogenesis imperfecta (OI) type IV have muscle force deficits. However, muscle function remains to be objectively quantified in this population. This study aimed to assess upper and lower extremity muscle function in patients with OI type IV. It was carried out in the outpatient department of a pediatric orthopedic hospital; 27 individuals with OI type IV (7-21 years; 13 males), 27 age- and sex-matched individuals with OI type I, and 27 age- and sex-matched controls. Upper extremity muscle force was assessed with hydraulic hand dynamometry, and lower extremity muscle function (peak force per body weight and peak power per body mass) was measured by mechanography through five tests: multiple two-legged hopping, multiple one-legged hopping, single two-legged jump, chair-rise test, and heel-rise test. Upper-limb grip force was normal for patients with OI type IV when compared to height and sex reference data (average z-score = 0.17 ± 1.30; P = 0.88). Compared to age- and sex-matched controls, patients with OI type IV had approximately 30% lower-limb peak force and 50% peak power deficits (P values <0.05). At the lower-limb level, they had a 50% lower peak power than age- and sex-matched patients with OI type I (P < 0.05). Patients with OI type IV have normal upper-limb muscle force but a muscle function deficit at the lower-limb level. These results suggest that lower-limb muscle weakness may contribute to functional deficits in these individuals.

Effect of high-dose vitamin D supplementation on bone density in youth with osteogenesis imperfecta: A randomized controlled trial

Osteogenesis imperfecta (OI) is a heritable condition characterized by fragile bones. Our previous studies indicated that serum 25-hydroxyvitamin D (25OHD) concentrations were positively associated with lumbar spine areal bone mineral density (LS-aBMD) in children and adolescents with OI. Here we assessed whether one year of high-dose vitamin D supplementation results in higher LS-aBMD z-scores in youth with OI. A one-year double-blind randomized controlled trial conducted at a pediatric orthopedic hospital in Montreal, Canada. Sixty patients (age: 6.0 to 18.9years; 35 female) were randomized in equal numbers to receive either 400 or 2000international units (IU) of vitamin D, stratified according to baseline bisphosphonate treatment status and pubertal stage. At baseline, the average serum 25OHD concentration was 65.6nmol/L (SD 20.4) with no difference between treatment groups (p=0.77); 21% of patients had results <50nmol/L. Vitamin D supplementation was associated with higher serum 25OHD concentrations in 90% of participants. The increase in mean 25OHD was significantly higher (p=0.02) in the group receiving 2000IU of vitamin D (mean [95% CI]=30.5nmol/L [21.3; 39.6]) than in the group receiving 400IU (15.2nmol/L [6.4; 24.1]). No significant differences in LS-aBMD z-score changes were detected between treatment groups. Thus, supplementation with vitamin D at 2000IU increased serum 25OHD concentrations in children with OI more than supplementation with 400IU. However, in this study where about 80% of participants had baseline serum 25OHD concentrations ≥50nmol/L, this difference had no detectable effect on LS-aBMD z-scores.

The functional muscle-bone unit in patients with osteogenesis imperfecta type I

CONTEXT

Osteogenesis imperfecta (OI) type I is a heritable bone fragility disorder that is caused by mutations affecting collagen type I. We recently showed that patients with OI type I frequently have muscle weakness. As muscle force and bone mass are usually closely related, we hypothesized that muscle weakness in OI type I could contribute to increase bone mass deficit in the lower extremities.

OBJECTIVE

To assess the muscle-bone relationship in the lower extremities of children and adolescents with OI type I.

SETTING

The study was carried out in the outpatients department of a pediatric orthopedic hospital. Patients and other participants Thirty children and adolescents with OI type I (20 females; mean age [SD]: 11.2 years [3.9]) were compared with 30 healthy age- and sex-matched controls (mean age [SD]: 11.1 years [4.5]).

MAIN OUTCOME MEASURES

Tibia bone mineral content (BMC; mg/mm) was measured by peripheral quantitative computed tomography to estimate bone strength at the 4% and 14% sites. Lower extremity peak force (kN) was measured by mechanography using the multiple two-legged hopping test.

RESULTS

Compared with age- and sex-matched controls, patients with OI type I had 17% lower peak force (1.3 kN vs. 1.7 kN; p=0.002) as well as a 22% lower BMC (128 mg/mm vs. 165 mg/mm; p<0.001). Stepwise regression analysis showed that muscle force and tibia length were positively related to bone strength (r(2)=0.90, p<0.001) whereas there was no effect of the disease status (OI vs. control).

CONCLUSIONS

These results suggest that the muscle-bone relationship is similar between children and adolescents with OI type I and healthy age and sex-matched controls. It also suggests that muscle weakness may contribute to decreased bone strength in individuals with OI type I.

Prism adaptation in virtual and natural contexts: Evidence for a flexible adaptive process

Prism exposure when aiming at a visual target in a virtual condition (e.g., when the hand is represented by a video representation) produces no or only small adaptations (after-effects), whereas prism exposure in a natural condition produces large after-effects. Some researchers suggested that this difference may arise from distinct adaptive processes, but other studies suggested a unique process. The present study reconciled these conflicting interpretations. Forty participants were divided into two groups: One group used visual feedback of their hand (natural context), and the other group used computer-generated representational feedback (virtual context). Visual feedback during adaptation was concurrent or terminal. All participants underwent laterally displacing prism perturbation. The results showed that the after-effects were twice as large in the "natural context" than in the "virtual context". No significant differences were observed between the concurrent and terminal feedback conditions. The after-effects generalized to untested targets and workspace. These results suggest that prism adaptation in virtual and natural contexts involves the same process. The smaller after-effects in the virtual context suggest that the depth of adaptation is a function of the degree of convergence between the proprioceptive and visual information that arises from the hand.

Validity of an accelerometer as a vertical ground reaction force measuring device in healthy children and adolescents and in children and adolescents with osteogenesis imperfecta type I

INTRODUCTION

Vertical ground reaction forces (vGRFs) are closely related to bone strength and development. It is therefore relevant to assess these forces in bone disorders accompanied with muscle weakness such as in osteogenesis imperfecta type I (OI type I). The purpose of the present study was to assess the validity of vGRFs derived from an accelerometer.

METHODS

Fourteen children and adolescents with a diagnosis of OI type I (age range: 7 to 21; mean age [SD]: 14.1 [4.8] years; 5 males) and fourteen healthy controls (age range: 6 to 21; mean age [SD]: 12.5 [4.2] years; 5 males) performed three repetitions of five different jump and rise tests on a ground reaction force plate. Jumps and rises outcomes were measured simultaneously with the ground reaction force plate and an accelerometer.

RESULTS

Pearson correlation coefficients were over 0.96 (p<0.001) for the five tests. The limits of agreement represented between 17 and 31% of the average peak force measured by both devices. The accelerometer is a promising tool to assess ground reaction forces in everyday life settings and has been shown to be sufficiently sensitive to detect muscular weakness in children and adolescent with OI type I.

Muscle anatomy and dynamic muscle function in osteogenesis imperfecta type I

CONTEXT

Results of previous studies suggested that children and adolescents with osteogenesis imperfecta (OI) type I have a muscle force deficit. However, muscle function has only been assessed by static isometric force tests and not in more natural conditions such as dynamic force and power tests.

OBJECTIVE

The purpose of this study was to assess lower extremity dynamic muscle function and muscle anatomy in OI type I.

SETTING

The study was performed in the outpatient department of a pediatric orthopedic hospital.

PATIENTS AND OTHER PARTICIPANTS

A total of 54 individuals with OI type I (6-21 years; 20 male) and 54 age- and sex-matched controls took part in this study.

MAIN OUTCOME MEASURES

Calf muscle cross-sectional area and density were measured by peripheral quantitative computed tomography. Lower extremity muscle function (peak force per body weight and peak power per body mass) was measured by jumping mechanography through 5 tests: multiple two-legged hopping, multiple one-legged hopping, single two-legged jump, chair-rise test, and heel-rise test.

RESULTS

Compared with age- and sex-matched controls, patients with OI type I had smaller muscle size (P = .04) but normal muscle density (P = .21). They also had lower average peak force and lower specific force (peak force/muscle cross-sectional area; all P < .008). Average peak power was lower in patients with OI type I but not significantly so (all P > .054).

CONCLUSIONS

Children and adolescents with OI type I have, on average, a significant force deficit in the lower limb as measured by dynamic force tests. Nonetheless, these data also show that OI type I is compatible with normal muscle performance in some individuals.

The muscle-bone relationship in X-linked hypophosphatemic rickets

CONTEXT

We recently found that patients with X-linked hypophosphatemic rickets (XLH) have a muscle function deficit in the lower extremities. As muscle force and bone mass are usually closely related, we hypothesized that patients with XLH could also have a bone mass deficit in the lower extremities.

OBJECTIVE

The study objective was to assess the muscle-bone relationship in the lower extremities of patients with XLH.

SETTING

The study was carried out in the outpatients department of a pediatric orthopedic hospital.

PATIENTS AND OTHER PARTICIPANTS

Thirty individuals with XLH (6 to 60 y; 9 male patients) and 30 age- and gender-matched controls participated.

MAIN OUTCOME MEASURES

Calf muscle size and density as well as tibia bone mass and geometry were assessed by peripheral quantitative computed tomography. Muscle function was evaluated as peak force in the multiple 2-legged hopping test.

RESULTS

Muscle force was significantly lower in XLH patients than in controls but muscle cross-sectional area did not differ (after adjustment for tibia length). External bone size, expressed as total bone cross-sectional area, was higher in the XLH group than in controls. The XLH cohort also had statistically significantly higher bone mineral content.

CONCLUSIONS

Patients with XLH have increased bone mass and size at the distal tibia despite muscle function deficits.

Cortical and trabecular bone density in X-linked hypophosphatemic rickets

CONTEXT

X-linked hypophosphatemic rickets is caused by mutations in PHEX. Even though the disease is characterized by disordered skeletal mineralization, detailed bone densitometric studies are lacking.

OBJECTIVE

The aim of the study was to assess volumetric bone mineral density (vBMD) in X-linked hypophosphatemic rickets using forearm peripheral quantitative computed tomography.

SETTING

The study was conducted in the metabolic bone clinic of a pediatric orthopedic hospital.

PATIENTS

Thirty-four patients (age, 6 to 60 years; 24 female) with PHEX mutations were studied, of whom 7 children (age, 6 to 11 years) were actively being treated with calcitriol and phosphate supplementation. Twenty-one patients (age, 16 to 40 years) had received the same therapy before but had discontinued the treatment; 6 patients (age, 12 to 60 years) had never received this treatment.

MAIN OUTCOME MEASURES

Trabecular and cortical vBMD of the radius.

RESULTS

Trabecular vBMD was elevated (mean age-specific and sex-specific z-score: +1.0) when all patients were analyzed together, due to very high results in currently treated patients (mean z-score: +2.4) and slightly above-average mean values in the other patients. Cortical vBMD was low when the entire cohort was analyzed together (mean z-score: -3.3), but was higher in currently treated patients (mean z-score: -1.3) than in patients who had discontinued therapy (mean z-score: -3.8) or who had never been treated (mean z-score: -4.1).

CONCLUSIONS

Patients with PHEX mutations have elevated trabecular vBMD at the distal radius while receiving calcitriol and phosphate supplementation, but low cortical vBMD at the radius diaphysis. Low cortical vBMD presumably reflects the underlying mineralization defect that is not entirely corrected by current treatment approaches.

Abnormalities in muscle density and muscle function in hypophosphatemic rickets

CONTEXT

Animal studies suggest that hypophosphatemic rickets (HPR) is associated with muscle function deficits, but it is unknown whether humans with HPR have a muscle disorder.

OBJECTIVE

Our objective was to assess calf muscle size and density (an indicator of muscle quality) and lower extremity muscle function in patients with HPR.

SETTING

The study was carried out in the outpatient department of a pediatric orthopedic hospital.

PATIENTS AND OTHER PARTICIPANTS

Participants included 34 individuals with HPR (6-60 yr; nine males) and 34 age- and gender-matched controls.

MAIN OUTCOME MEASURES

Calf muscle parameters (muscle cross-sectional area and density) were measured by peripheral quantitative computed tomography. Lower extremity muscle function (peak force per body weight and peak power per body mass) was measured by jumping mechanography through five tests with different levels of difficulty: multiple two-legged hopping, multiple one-legged hopping, single two-legged jump, chair-rise test, and heel-rise test.

RESULTS

Compared with age- and gender-matched controls, patients with HPR had normal muscle size (P = 0.58) but lower muscle density (P = 0.008) and lower peak muscle force and power (P < 0.001 in each test). Muscle function tests were also lower in the subgroup of patients with straight legs (n = 13) than in controls, even though patients with straight legs had higher muscle function test results than patients with severe leg deformities.

CONCLUSIONS

The present study suggests that muscle weakness is a clinical feature of HPR. Lower muscle quality and limb deformities contribute to this functional deficit.

Gait analysis using a force-measuring gangway: intrasession repeatability in healthy adults

OBJECTIVES

The goal of the present study was to determine the repeatability of gait parameters measured by a force plate gait analysis system (Leonardo Mechanograph® GW).

METHODS

Fifteen healthy adult participants walked at a self-selected speed on a 10 m long walkway. Vertical ground reaction forces were measured in the central 6 m of the walkway. Each participant performed three trials while walking barefoot and three trials while wearing shoes, each trial consisting of three 10 m walks.

RESULTS

There were minimal differences between trials at each condition. All primary force, time, distance and velocity parameters had intraclass correlation coefficients above 0.90 and coefficients of variation in the order of 2% to 4%. Compared to walking barefoot, walking in shoes resulted in 14% lower maximal vertical ground reaction force, 5% longer step length and 2% higher average velocity and caused less lateral translation of the center of force.

CONCLUSIONS

In this group of healthy adults, gait analysis with a force plate system produced repeatable intra-day results. The observation that barefoot and shod walking yield different results indicates that it is important to standardize test conditions.