Functional results of operation in osteogenesis imperfecta: elongating and nonelongating rods

Complications of Elongating Intramedullary Rods in the Treatment of Lower Extremity Fractures for Osteogenesis Imperfecta: A Meta-Analysis of 594 Patients in 40 Years

BACKGROUND

Osteogenesis imperfecta is a collagen mutation-related disease characterized by bone fragility and other extraskeletal manifestations. Intramedullary fixation for deformity correction or fracture is the standard care. Elongating rods are designed to accommodate growth, with the aim of preventing additional operations and/or complications associated with nonelongating rods. Although elongating rods have been in use for many years, estimates of the clinical outcomes vary. We conducted a systematic review and meta-analysis to synthesize the literature on outcomes of elongating rods and nonelongating rods. Meta-analysis was used to compare the complication rates and reoperation rates.

METHODS

We conducted the literature search, systematic review, and meta-analysis in accordance with Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) guidelines. Comparative cohort studies and large case series detailing complication rates and reoperation rates of elongating and nonelongating rods were included. Random effect models were used to summarize the complication rates and reoperation rates of intramedullary rod procedures.

RESULTS

A total of 397 studies were identified and 24 studies were included in the final cohort. Compared with rates from nonelongating rods, osteogenesis imperfecta Patients using elongating rods had a complication rate of 61% and a reoperation rate of 78%. Reoperation rates dropped with succeeding generations of elongating rods. Pooling data from 600 patients, we identified a 9% complication rate per rod per follow up year and 5% reoperation rate per rod and per follow up year in the cohort of elongating rod fixation. The Bailey-Dubow rod had the highest complication rate per rod per follow up year (12%), largely because of its T piece relate problems. The most popular fixator Fassier-Duval rod had a complication rate per rod per follow up year of 9%. About 68% of complications were mechanical-biological related.

CONCLUSION

Pooling data from published literature demonstrates the advantage of elongating rods over nonelongating rods. However, as high as 9% complication rate per rod per follow up year was associated with elongating fixation. Notably, most complications are both mechanical and biological related.

LEVEL OF EVIDENCE

Level III.

Interlocking Fixation in Fassier-Duval Rods: Performance and Success Factors

INTRODUCTION

Pediatric patients with osteogenesis imperfecta (OI) can be treated with intramedullary Fassier-Duval rod (FDR) systems for limb deformity or recurrent fractures. Single-interlocking pins can improve epiphyseal fixation, but there is a paucity of literature examining incidence of rod migration or pin backout long-term. The purpose of this study is to quantify rates of rod migration and pin backout in OI patients treated with single-interlocking FDRs.

METHODS

A retrospective chart review was performed on pediatric patients treated at a tertiary care center across a 15-year period. Inclusion criteria to select patients was: (1) Pediatric patients (below 18 y of age); (2) Patients with confirmed OI; and (3) Patients with lower extremity fractures or deformity treated with FDRs with distal interlocking pins. Age at time of surgery, rates of obturator migration and pin backout and prominence were collected. We recorded if pin tips were bent by the surgeon during the procedure. Bivariate statistics were used to analyze risk factors for pin backout and prominence.

RESULTS

Twenty-four single-interlocking pin FDRs (21 tibia, 3 femur) were identified. The mean age at index surgery was 5.7±3.4 years, with the mean follow-up time of 7.2±4.7 years. Fourteen (58%) rods underwent revision surgery. Obturator proximal migration was observed in 3/24 rods (13%). No cases of obturator distal migration were observed (0/24, 0%). Mean proximal obturator migration was 2.16±1.8 cm. Revision for pin backout was observed in 10 (42%) rods and pin prominence in 11 (46%) extremities. Bending interlocking pins on at least 1 end was associated with decreased pin backout (P=0.01) and prominence (P=0.04).

CONCLUSIONS

Even with distal interlocking pins, the obturator of FDRs can still migrate over time. Pin backout is a common indication for revision surgery. Bending interlocking pins can decrease rates of pin backout and prominence.

LEVEL OF EVIDENCE

Level III.

Telescopic rodding in children: Technical progression from Dubow-Bailey to Fassier-Duval™

Medical and surgical treatment of osteogenesis imperfecta has undergone two revolutions that improved quality of life and functional capacity: reduced bone absorption with the use of bisphosphonates, and improvement in internal fixation with the development of Dubow-Bailey then Fassier-Duval™ telescopic rodding. Telescopic intramedullary rodding in osteogenesis imperfecta and in other pathologies (congenital non-union and other congenital bone disorders) progressed with the replacement of the Dubow-Bailey rod by the telescopic Fassier-Duval™ rod. The aim of the present study was to provide an update on a technique that requires the utmost rigor and is not free of complications. Pitfalls and tips-and-tricks are presented in the light of our own experience.

Results of Rodding and Impact on Ambulation and Refracture in Osteogenesis Imperfecta: Study of 21 Children

INTRODUCTION

Delay in presentation and surgical intervention is quite usual in osteogenesis imperfecta (OI) because of various local and cultural beliefs. The purpose of this study is to review the results of 21 children who had intramedullary rodding and its effect on ambulation and refracture.

METHODS

We reviewed 21 children with a clinical diagnosis of OI. The mean age of children at presentation was 8.74 years (3-21 years). All children had recurrent fractures of long bones. Twenty eight femurs and 21 tibiae were stabilized with intramedullary rodding. Ambulatory status was assessed by the Hoffers and Bullock's (H and B) grading, and muscle power was recorded using the Medical Research Council, U. K., grade. Ten children had received intravenous bisphosphonates preoperatively. Postoperatively, the children were assessed for ambulatory status, pain, and ability for independent self-care.

RESULTS

The mean followup period was 34 months (24-48 months). Rush rods were used in 20 femurs, the Fassier-Duval (FD) rods in 6 femurs, and in two cases, with narrow intramedullary canals, Kirshner (K) wires were used. For the tibiae, 15 children received rush rods and in 6 cases, an FD rod was used. The mean time to fracture union was 8 weeks (6-12 weeks). Before surgery, 13 children were in H and B Grade 4 (wheel-chair independent or carried by parents usually in a developing country), four were able to ambulate with a walking aid (H and B Grade 3b), and four children were able to walk about in the house without aids (H & B Grade 2). After the rodding procedure, the ambulatoty status improved in 11 (50%) children. Seven children (33%) became household physiologic walkers (H & B Grade 3b), three achieved independent ambulation with orthosis (H & B Grade 1b), and one child with mild OI could walk unaided (H & B Grade 1a). No child had deterioration in ambulatory status. Only two children had refractures at the distal end of the rod due to continual growth of bones.

CONCLUSIONS

Intramedullary rodding treatment for recurrent fractures in children with OI improves their mobility potential. It also and prevents repeated cast application, disuse wasting, and osteopenia which can lead to deterioration in the quality of the long bones.

Effects of a telescopic intramedullary rod for treating patients with osteogenesis imperfecta of the femur

PURPOSE

To introduce a new model of telescopic intramedullary rod (TIR), evaluate its effects on treating patients presenting with moderate and severe osteogenesis imperfecta (OI) and to compare the findings with those of other telescopic rods.

METHODS

A total of 21 patients (nine girls and 12 boys; mean age at first operation, 6.6 years, 1.52 to 13.18) who underwent 52 femoral operations were monitored during a mean of 9.96 years (3.39 to 14.54). Patient characteristics, telescoping rod capability and its complications were examined.

RESULTS

According to the Sillence classification, we investigated one patient with type I, nine with type III and 11 with type IV OI. Revision rates at up to five years (36%) were inferior to those found for the Fassier-Duval rod (46%). The main cause of revision was fracture (15 patients), followed by rod migration (nine), and infection (two). The rod exhibited higher telescopic capacity in boys than girls. Type III most commonly required an operation; the age group with the highest number of procedures was five to ten years. Male migration was the main cause of rod migration.

CONCLUSION

The TIR has a satisfactory cost-benefit ratio with less complication rates and low production costs. The TIR is a feasible alternative to the commonly used Fassier-Duval rod.

LEVEL OF EVIDENCE

IV.

The Outcomes of Nonelongating Intramedullary Fixation of the Lower Extremity for Pediatric Osteogenesis Imperfecta Patients: A Meta-analysis

BACKGROUND

Osteogenesis imperfecta is usually due to autosomal dominant mutations in type I collagen, leading to an increase in fractures and bone deformities, especially in the long bones of the lower extremities. The use of nonelongating intramedullary rods is an established surgical intervention to address such deformities. The rate of surgical complications has been reported to be as high as 187%, with revision rates as high as 90%, although exact global rates are unknown. As such, we sought to determine the published rates of (1) bone-related complications (including both fracture and deformity), (2) rod migration, and (3) complications that require reoperation.

METHODS

Following the Preferred Reporting Items for Systematic reviews and Meta-analyses (PRISMA) guidelines, 1295 studies were evaluated. After cross-referencing, and applying specific inclusion and exclusion criteria, a total of 7 studies were included in the final cohort. Data were extracted from the studies and analyzed. Random effect models determined the complication rates of intramedullary nonelongating rod procedures.

RESULTS

A total of 359 primary nonelongating intramedullary rod procedures of tibiae and femurs, in patients with a mean age of 6 years (5.2 to 7.3 y), at a mean follow-up of 63 months (24 to 118 mo), were evaluated. 60% of the surgical procedures were on femurs, and 40% were on tibiae. The reoperation rate was 39.4%. The most common complication was rod migration, with a rate of 25.7%. The rate of bone-related complications was 19.5% including fractures (15.0%) and worsening bone deformity (4.3%).

CONCLUSIONS

This is the first meta-analysis to identify the rates of complication and reoperation in lower limb intramedullary fixation for pediatric osteogenesis imperfecta patients. This study has shown that rod migration is the most common complication, followed by bone-related complications including fractures and deformity. Reoperations occur after nearly 40% of all procedures due to rod migration or bone-related complications.

LEVEL OF EVIDENCE

Level IV-retrospective meta-analysis.

Managing the patient with osteogenesis imperfecta: a multidisciplinary approach

Osteogenesis imperfecta (OI) is a heterogeneous heritable connective tissue disorder characterized by low bone density. The type and severity of OI are variable. The primary manifestations are fractures, bone deformity, and bone pain, resulting in reduced mobility and function to complete everyday tasks. OI affects not only the physical but also the social and emotional well-being of children, young people, and their families. As such, medical, surgical, and allied health professionals’ assessments all play a role in the management of these children. The multidisciplinary approach to the treatment of children and young people living with OI seeks to provide well-coordinated, comprehensive assessments, and interventions that place the child and family at the very center of their care. The coordinated efforts of a multidisciplinary team can support children with OI to fulfill their potential, maximizing function, independence, and well-being.

Custom hemiarthroplasties for retention of existing hardware associated with osteogenesis imperfecta

Osteogenesis imperfecta is a rare genetic disorder that presents with heterogeneous phenotypes ranging from brittle bones to impaired hearing. Because of the decreased bone mineral density frequently observed in this patient population, many patients experience recurring and long-term fractures, which often require orthopaedic management. With the advancement of nonsurgical and surgical management and increased longevity of patients with osteogenesis imperfecta, the incidence of osteoarthritis has risen, presenting new orthopaedic challenges. However, compromised bone integrity and size combined with frequent existing hardware render traditional surgical therapies for osteoarthritis technically challenging in this patient population. In this report, we present a case in which we retained a portion of the patient's existing hardware, while performing staged bilateral custom hemiarthroplasties in a patient with osteogenesis imperfecta.

Effect of Different Distal Fixation Augmentation Methods on the Pullout Strength of Fassier-Duval Telescoping Rods

Antegrade telescoping rods have been introduced for use in pediatric patients with osteogenesis imperfecta (OI) to decrease the incidence of long-bone fractures and to correct and prevent deformities. Recent studies have documented failures of telescoping intramedullary rods due to inadequate distal fixation. The purpose of this study was to evaluate the pullout strength of distal fixation of the telescoping rod with and without synthetic calcium phosphate or polymethylmethacrylate (PMMA) augmentation. Four sets of 6 telescoping distal fixation rods were fixed according to standard insertion technique into an open-cell rigid-foam synthetic bone block simulating OI bone. The groups tested were as follows: control (no augmentation), 0.75 mL of PMMA-augmented, 0.75 mL of PMMA-rescued (stripped distal fixation, then resecured after PMMA augmentation), and 0.75 mL of bioabsorbable-calcium phosphate (CP)-augmented. All rods were tested to failure. The peak load was recorded. Average pullout strengths were as follows: control, 20±6.6 N; PMMA, 125±16.8 N; PMMA-rescued, 137±11.9 N; bioabsorbable-CP, 81±10.3 N. All augmented groups had significantly higher pullout strength compared with the control (P<.001). The PMMA and PMMA-rescued groups failed at the PMMA/bone interface, whereas the bioabsorbable-CP group failed at the cement/rod interface. All augmented constructs improved pullout strength by at least 400% compared with the control. Bioabsorbable cement may be less detrimental to the physis if pullout still occurs despite augmentation due to its mode of failure. This study provides biomechanical evidence to support the further in vivo investigation of either PMMA or bioabsorbable cement augmentation to improve pullout strength of distal telescoping rod fixation.

Primary and revision total hip arthroplasty in osteogenesis imperfecta

Due to an increasing lifespan, patients with osteogenesis imperfecta have a high incidence of hip osteoarthritis. The presence of recurrent fractures and deformities make primary and particularly revision total hip arthroplasty challenging. We present a series of patients with osteogenesis imperfecta undergoing total hip arthroplasty at a tertiary referral centre with a median follow-up of 7.6 years (4 to 35 years). There were four primary total hip arthroplasties and eight revision total hip arthroplasties performed in four patients. Three femoral components were custom computer assisted design computer assisted manufactured. The survival rate of the primary total hip arthroplasty was 16% and there were ten complications: five intraoperative fractures, one case of septic loosening and four cases of aseptic loosening. Patients with pre-operative acetabular protrusio were significantly more likely to require revision surgery (p = 0.02). At latest follow-up, the median Oxford hip score was 41 (37 to 46). As the largest series of primary and revision total hip arthroplasty performed in patients with osteogenesis imperfecta, we report good medium to long-term outcomes. Preoperative planning and consideration of custom made prostheses have an important role in these complex cases.

Use of the Sheffield telescopic intramedullary rod system for the management of osteogenesis imperfecta: clinical outcomes at an average follow-up of nineteen years

BACKGROUND

Elongating intramedullary rods have been used in the management of osteogenesis imperfecta for the past fifty years. The complication rates reported in many reviews of the available techniques have been high. This study reviews the long-term functional outcomes and complications following the use of the Sheffield system of telescopic intramedullary rods.

METHODS

We conducted a retrospective analysis of patients with osteogenesis imperfecta who were at least eighteen years of age and who had at least thirteen years of follow-up. Complications, reoperations, and data from a disease-specific questionnaire and the Short Form-36 questionnaire were recorded.

RESULTS

Data for twenty-two patients with osteogenesis imperfecta who had been treated with Sheffield telescopic intramedullary rods were available at an average of nineteen years after the initial surgery. Reoperations involving thirty-three (50%) of the sixty-six rods were performed: ten rods (15%) were exchanged because of rod disengagement due to growth, thirteen rods (20%) were exchanged because of complications, and ten rods (15%) required further surgery other than exchange because of complications. Mobility was significantly improved at the initial postoperative visit (p = 0.0015), and this improvement was maintained into adulthood (p = 0.0077). Back pain was the most frequent symptom. Symptoms related to rod insertion across the knee and ankle were rare, but symptoms related to proximal femoral trochanteric entry were common. Physeal damage was not seen following surgery, and all rods elongated with growth. All patients were satisfied with the outcome of the surgical procedures. Short Form-36 scores for all physical domains and for social function and vitality were significantly worse than those in a normal population.

CONCLUSIONS

The outcomes of this technique are satisfactory in adulthood; reoperation rates are high but are most commonly related to the patient outgrowing the rods. Concerns regarding insertion of this fixed device at the knee and ankle were unfounded, although proximal femoral fixation remains a problem.

Experience with the Fassier-Duval telescopic rod: first 24 consecutive cases with a minimum of 1-year follow-up

BACKGROUND

The new Fassier-Duval Telescopic IM System (FD-rod) has the advantage of a single entry point over the traditional telescopic rods such as the Bailey-Dubow or Sheffield rods. Although encouraging early results were presented by the originators of the technique at international meetings, there is no formal publication in the literature as yet.

METHODS

We performed a chart and x-ray review of the first 24 consecutive FD-rod insertions in 15 patients (age, 1.5 to 12.5 y) with a minimum of 1-year follow up (1 to 2.4 y) after implantation of femoral and/or tibial FD-rods. Diagnoses included with osteogenesis imperfecta (OI) (15 cases, 9 patients), and other conditions such as congenital tibial pseudarthrosis (CPT) in neurofibromatosis type 1 (NF1) (2 cases), and epidermal naevus syndrome (1 case). In patients with hypophosphataemic rickets (6 cases, 2 patients) the FD-rods were combined with an Ilizarov frame.

RESULTS

We found the OI patient group associated with a 13% reoperation rate (2 of 15 cases) for proximal rod migration and a 40% complication rate (6 of 15 cases): rod migration and limited telescoping (5) and intraoperative joint intrusion (1). There were no infections. All the NF1 CPT (2) and epidermal naevus syndrome (1) cases required several reoperations for nonunion, loss of fixation, shortening (negative telescoping), migration, and/or joint intrusion-mainly due to the severe underlying pathology with insufficient longitudinal or torsional stability and diminished healing capacity. In hypophosphataemic rickets (combined with Ilizarov frame fixation) we found a 50% complication rate (3 of 6 cases) and a 17% reoperation rate (1 of 6): 2 FD-rods did not telescope and 1 case of peroneal neuropraxia required neurolysis.

CONCLUSIONS

In our experience the technique of using FD rods is demanding and associated with some intraoperative and postoperative pitfalls. We are happy to continue its use in OI patients when there is longitudinal stability and sufficient bone healing. However, in circumstances of insufficient stability and bone healing potential, further stabilization that can be achieved with an Ilizarov frame may be beneficial.

Sobrevida de uma haste intramedular extensível (HIMEX) no tratamento de crianças com ostegênese imperfeita

OBJETIVO: avaliar o desempenho da haste extensível ancorada por ganchos (HIMEX) em deformidades da osteogênese imperfeita (OI). MÉTODOS: Todas as crianças operadas com HIMEX entre 1990 - 2004. Foi comparado o número de fraturas, reaparecimento de deformidades e capacidade de deambulação antes e após a HIMEX; incidência de migração e sobrevida da haste por curvas de sobrevivência. RESULTADOS: 14 pacientes (2 a 18 anos), oito do sexo feminino, incluindo 46 procedimentos, 39 primários e sete re-operações. Idade média na primeira fratura de 148,21 dias e média de 42,6 fraturas/paciente pré colocação da HIMEX. Dos 46 procedimentos, 28 no fêmur e 18 na tíbia. Tempo médio de seguimento de 80,21 ± 36,71 meses. Houve diminuição significativa de fraturas/paciente (0,78) e melhora na deambulação em sete dos 14 pacientes. Porcentagem de re-operação de 18% e migração do implante em 12% (05/39). 80 % dos implantes in situ até 108 meses. Implantes na tíbia tiveram sobrevida significativamente menor que os do fêmur. O tipo da OI e a idade na época da cirurgia não influenciaram significativamente a incidência de re-operação. CONCLUSÃO: A HIMEX levou à redução significativa no número de fraturas, incidência menor de migração e sobrevida maior da haste do que a referida na literatura.

Tratamento cirúrgico das deformidades e fraturas em membros inferiores na osteogênese imperfeita

OBJETIVO: Fazer uma revisão dos pacientes portadores de Osteogênese Imperfeita avaliando o tratamento cirúrgico das fraturas e deformidades nos membros inferiores para determinar a eficiência da técnica utilizando as hastes fixas (não-extensíveis). CASUÍSTICA E MÉTODO: Foram revisados os prontuários, radiografias pré-operatórias e pós-operatórias de todos os pacientes portadores de Osteogênese Imperfeita que foram tratados no Alfred I duPont Institute (EUA) entre 1965 e 1999. RESULTADOS: Quatorze pacientes (cinco meninos e nove meninas) foram submetidos às hastes fixas nos membros inferiores com um total de 37 procedimentos realizados. CONCLUSÃO: O procedimento de fixação intramedular com hastes não extensíveis mostrou ser um método de baixa morbidade, capaz de manter e até mesmo de melhorar o status de deambulador destes pacientes.

Results of a prospective pilot trial on mobility after whole body vibration in children and adolescents with osteogenesis imperfecta

OBJECTIVE

To evaluate the effect of whole body vibration on the mobility of long-term immobilized children and adolescents with a severe form of osteogenesis imperfecta. Osteogenesis imperfecta is a hereditary primary bone disorder with a prevalence from 1 in 10000 to 1 in 20000 births. Most of these children are suffering from long-term immobilization after recurrent fractures. Due to the immobilization they are affected by loss of muscle (sarcopenia) and secondary loss of bone mass.

SUBJECTS

Whole body vibration was applied to eight children and adolescents (osteogenesis imperfecta type 3, N=5; osteogenesis imperfecta type 4, N=3) over a period of six months.

INTERVENTIONS AND RESULTS

Whole body vibration was applied by a vibrating platform (Galileo Systems) constructed on a tilting-table. Success of treatment was assessed by measuring alterations of the tilting-angle and evaluating the mobility (Brief Assessment of Motor Function). All individuals were characterized by improved muscle force documented by an increased tilting-angle (median = 35 degrees) or by an increase in ground reaction force (median at start=30.0 [N/kg] (14.48-134.21); median after six months = 146.0 [N/kg] (42.46-245.25).

CONCLUSIONS

Whole body vibration may be a promising approach to improve mobility in children and adolescents severely affected with osteogenesis imperfecta.

Modified Sofield-Millar operation: less invasive surgery of lower limbs in osteogenesis imperfecta

We present the results of intramedullary rodding of long bones of the lower limbs in children with osteogenesis imperfecta using a modified Sofield-Millar operation. Fourteen patients (mean age at primary operation was 5 years 11 months) were treated with a modified Sofield-Millar operation which allows minimal bone exposure, preservation of the periosteum and keeping the number of osteotomies to the minimum. Union was achieved in all cases within 7 weeks. Of the 14 patients (29 bones) treated with nonelongating rods, rod revisions were needed in 13 patients (26 bones). We found no statistically significant difference between the width of the bone immediately postoperatively and at the final follow-up. The walking ability was improved in four patients. Advantages of less invasive surgery in osteogenesis imperfecta are rapid bone union, no bone atrophy or nonunion, better postoperative mobility and small scars.

[Diagnosis and therapy of osteogenesis imperfecta]

Osteogenesis imperfecta (OI) is a congenital connective tissue disorder with an incidence of up to 1:30,000. Patients suffer from deformities and fractures, and many of them never reach ambulation. The therapy consists of conservative, medicamentous and operative procedures that are described in this article.

Interlocking telescopic rod for patients with osteogenesis imperfecta

BACKGROUND

Intramedullary fixation with use of a telescopic rod with a T-piece is one of the standard methods for long-bone stabilization in growing children with osteogenesis imperfecta. However, installation and removal of this device can cause substantial damage to the distal joint, which limits its use, especially in the tibia. We devised a modification of the telescopic rod system--the interlocking telescopic rod--in which the obturator is a simple rod with a hole, instead of a T-piece, at its distal end.

METHODS

The clinical and radiographic outcomes were evaluated more than two years following treatment of thirty-two limb segments (twenty-three tibiae and nine femora) with this new rod system in fifteen patients with osteogenesis imperfecta.

RESULTS

All rods were inserted without an arthrotomy of the distal joint, and all telescoped successfully. The interlocking pin used in the first five limb segments backed out between five and thirty-three months postoperatively. A revised fixation technique was used in the remaining twenty-seven limb segments, and the interlocking pin had not backed out at an average 3.1 years postoperatively. Proximal migration of the obturator was observed in four tibiae after 2.5 years. The cumulative survival rate of the rod at four years postoperatively was 88.7%.

CONCLUSIONS

Both insertion and removal of an interlocking telescopic rod are much less invasive than insertion and removal of a conventional telescopic rod with a T-piece anchor. The interlocking pin at the distal epiphysis provides effective anchorage for telescoping. Our interim results showed survival of the device to be comparable with, or better than, that of the conventional telescopic rod.

The choice of intramedullary devices for the femur and the tibia in osteogenesis imperfecta

The results of intramedullary rodding of 50 femoral and 25 tibial segments were analyzed retrospectively. The techniques of femoral rodding included single Rush rodding, dual Rush rodding and Sheffield telescoping rodding. Single Rush rods or Sheffield rods were used in the tibia. The frequencies of fractures following rodding and implant-related complications and the interval between initial rodding and rod revision were analyzed. The longevity of the rods was evaluated by survival analysis. In the femur, dual Rush rods and Sheffield rods were equally effective and both were superior to a single Rush rod with reference to each of the outcome variables. The technique of dual Rush rodding was more demanding than telescoping rodding. In the tibia, a single Rush rod was as effective as a Sheffield telescoping rod. Based on our results, a single Rush rod would be the preferred implant in the tibia while in the femur, dual Rush rods or a Sheffield telescoping rod may be preferred.

Arthroscopic-assisted revision of telescopic rods in osteogenesis imperfecta

Bailey-Dubow extensible nails are intramedullary stabilization devices designed to prevent deformities and recurrent long bone fractures in patients with osteogenesis imperfecta. The rods consist of a hollow outer sleeve and a solid inner obturator, allowing for telescoping of the rods and expansion of the device with longitudinal growth of the bone. Migration of the nail into the joint is a known complication of this procedure, which can lead to pain and loss of motion. This is a case report of the use of an arthroscopic approach to manipulate femoral and tibial Bailey-Dubow rods that migrated into the knee joint.

A operação de Sofield e Millar no tratamento da osteogênese imperfeita

A osteogênese imperfeita é uma doença genética causada por um defeito do colágeno do tipo I. Os portadores caracterizam-se pela baixa estatura, escleras azuladas, deformidades esqueléticas e fragilidade óssea. Os autores analisam os resultados da operação de Sofield e Millar que foi realizada em 23 ossos acometidos em oito portadores de osteogênese imperfeita com deformidades e antecedentes de múltiplas fraturas. Após um seguimento médio de dez anos e dois meses, onze ossos não precisaram ser reoperados; doze ossos, no entanto, apresentaram 21 complicações pós-cirúrgicas sendo: dez migrações das hastes intra-medulares, seis refraturas, três recidivas da deformidade e duas pseudartroses. Não houve caso de infecção ou lesão neurovascular. A reoperação, quando necessária, ocorreu após um tempo médio de três anos e seis meses. Todos os pacientes melhoraram ou mantiveram a capacidade de deambulação logo após a cirurgia; porém, com o tempo, dois deles, portadores de formas mais graves da doença, deterioraram sua capacidade de deambulação tornando-se não deambuladores. Os autores concluem que a operação torna possível a correção das deformidades e previne temporariamente a sua recidiva, além de tornar as fraturas menos freqüentes. No entanto, devido ao crescimento esquelético e a indistensibilidade das hastes intramedulares utilizadas, as complicações ocorrem.

[Elastic sliding central medullary nailing with osteogenesis imperfecta. Fourteen cases at eight years follow-up]

PURPOSE OF THE STUDY

Elastic sliding centromedullary nailing (ESCN) proposed by Métaizeau in 1987 for the prevention and treatment of limb fractures in osteogenesis imperfecta has never been evaluated. A multicentric serie was studied in order to evaluate results of these procedure.

MATERIAL AND METHODS

Thirty-six ESCN procedures were performed in fourteen patients. Percutaneous pinning was used for the femur and distal tibia and arthrotomy for the distal femur as needed and in all cases for the proximal tibia. The pins were bent in compliance with the principles of the ESCN system. The ends of the pins were bent back to form a U pushed into the epiphysis. Reaxing osteotomies required minimal incisions. Age at the first procedure, the number of procedures and complications, and time between procedures were recorded. Pin overlap and the angle formed were also recorded. Pin gliding was evaluated. Ability to walk with or without assistance was noted.

RESULTS

The medullary canal measured 4 to 10 mm. The first procedure was performed at a mean age of four years (range 15 days to 10 years). Follow-up was eight years (range 1-12). There were 2.5 procedures per patient (range 1-5). Pins had to be changed in 75% of the bone segments. Mean time between two procedures was 3.2 years. There were no cases of defective sliding or infection. There were four cases of secondary fracture with a mean 30% pin overlap, two pin migrations, one nonunion, and one shortening. The majority of the complications occurred after the age of five years. At last follow-up, three patients could not walk, four walked with aids, and eight without aids.

DISCUSSION

The advantages of the technique (size of the pins, nailing without reaming, pin sliding in all cases, low cost) must not overshadow the drawbacks (risk of pin deformation and migration, secondary fracture). Secondary fractures might be limited by discrete valgus of the femoral shaft and preventive pin change when the angle formed approaches 30 degrees and when there is only 30% overlap left. Use of telescopic nails before the age of five years increases the risk of complications while most of the complications observed with ESCN occur after the age of five years. Twenty-five percent of the ESCN complications involved only the femur. The percent of secondary fractures was less than with telescopic nailing (3.6% versus 11%) but there were more cases of nail migration. All pins slid, compared with 6% failure of elongation with telescopic nails. Although proof is not available, surgical treatment of osteogenesis imperfecta before the age of five years appears to provide more rapid functional progress.

CONCLUSION

Sliding centromedulary nailing is an attractive alternative before the age of five years. In older children and to the end of growth, telescopic nail or pinning should be discussed although pinning may permit more secondary fractures which can be limited by rigorous surveillance of pin position.

Gene therapy approaches for osteogenesis imperfecta

Osteogenesis imperfecta (OI) is a heterogeneous group of genetic disorders that affect connective tissue integrity. The hallmark of OI is bone fragility, although other manifestations, which include osteoporosis, dentigenesis imperfecta, blue sclera, easy bruising, joint laxity and scoliosis, are also common among OI patients. The severity of OI ranges from prenatal death to mild osteopenia without limb deformity. Most forms of OI result from mutations in the genes that encode either the proalpha1or proalpha2 polypeptide chains that comprise type I collagen molecules, the major structural protein of bone. Treatment depends mainly on the severity of the disease with the primary goal to minimize fractures and maximize function. Current treatments include surgical intervention with intramedullarly stabilization and the use of prostheses. Pharmacological agents have also been attempted with limited success with the exception of recent use of bisphosphonates, which have been to shown to have some effect. Since OI is a genetic disease, these agents are not expected to alter the course of the collagen mutations. Cell and gene therapies as potential treatments for OI are therefore currently being actively investigated. The design of gene therapies for OI is however complicated by the genetic heterogeneity of the disease and by the factor that most of the OI mutations are dominant negative where the mutant allele product interferes with the function of the normal allele. The present review will discuss the molecular changes seen in OI, the current treatment options and the gene therapy approaches being investigated as potential future treatments for OI.

Advances in osteogenesis imperfecta

Considerable progress has been made in many aspects of osteogenesis imperfecta. The international Sillence classification of osteogenesis imperfecta is being expanded to include a greater range of subgroups of patients. Attempts are being made to identify the genes causing forms of osteogenesis imperfecta and related syndromes that are not caused by mutations of the Type I collagen genes. In medium-term studies, bisphosphonate treatment has been shown to be the first method of treatment to improve the clinical course of the disease significantly. Somatic cell therapy, using allogeneic bone marrow and mesenchymal stromal cell transplantation, are in their early phases of development for use in humans with osteogenesis imperfecta. Somatic gene therapy, which aims to inactivate the mutation, is being evaluated in laboratory and animal studies.

Osteogenesis imperfecta in childhood: prognosis for walking

OBJECTIVES

We studied the predicted value of disease-related characteristics for the ability of children with osteogenesis imperfecta (OI) to walk.

STUDY DESIGN

The severity of OI was classified according to Sillence. The parents were asked to report the age at which the child achieved motor milestones, the fracture incidence, and the age and localization of the first surgical intervention. The present main means of mobility was classified according to Bleck.

RESULTS

There were 76 replies to the 98 questionnaires, of which 70 were included (type I, 41; type III, 11; type IV, 18). The type of OI was strongly associated with current walking ability, as was the presence of dentinogenesis imperfecta. Patients with type III and IV had a lower chance of ultimately walking compared with those with type I. Children with more than 2 intramedullary rods in the lower extremities had a reduced chance of walking than patients without rods. Rolling over before 8 months, unsupported sitting before 9 months, the ability to get in sitting position without support before 12 months, and the ability to get in a standing position without support before 12 months showed positive odds ratios. In Bleck > or = 4, multivariate analysis revealed that only the presence of rodding (yes/no) in the lower extremities had additional predictive value to the type of OI. The presence of dentinogenesis imperfecta and rodding (yes/no) had additional value in Bleck > or = 5.

CONCLUSION

The type of OI is the single most important clinical indicator of the ultimate ability to walk. Information about motor development adds little. The early achievement of motor milestones contributes to the ability of independent walking when the type of OI is uncertain. Intramedullary rodding of the lower extremities is primarily related to the severity of the disease and in this way provides consequences for the ability to walk.

Osteogenesis imperfecta in childhood: treatment strategies

Osteogenesis imperfecta (OI) is a skeletal disorder of remarkable clinical variability characterized by bone fragility, osteopenia, variable degrees of short stature, and progressive skeletal deformities. Additional clinical manifestations such as blue sclerae, dentinogenesis imperfecta, joint laxity, and maturity onset deafness are described in the literature. OI occurs in about 1 in 20,000 births and is caused by quantitative and qualitative defects in the synthesis of collagen I. Depending on the severity of the disease, a large impact on motor development, range of joint motion, muscle strength, and functional ability may occur. Treatment strategies should primarily focus on the improvement of functional ability and the adoption of compensatory strategies, rather than merely improving range of joint motion and muscle strength. Surgical treatment of the extremities may be indicated to stabilize the long bones to optimize functional ability and walking capacity. Surgical treatment of the spine may be indicated in patients with progressive spinal deformity and in those with symptomatic basilar impression.

Osteogenesis imperfecta

Osteogenesis imperfecta (OI) is a genetically determined disorder of connective tissue characterized by bone fragility. The disease state encompasses a phenotypically and genotypically heterogeneous group of inherited disorders that result from mutations in the genes that code for type I collagen. The disorder is manifest in tissues in which the principal matrix protein is type I collagen (mainly bone, dentin, sclerae, and ligaments). Musculoskeletal manifestations are variable in severity along a continuum ranging from perinatal lethal forms with crumpled bones to moderate forms with deformity and propensity to fracture to clinically silent forms with subtle osteopenia and no deformity. The differential diagnosis includes other entities with multiple fractures, deformities, and osteopenia. Classification is based on the timing of fractures or on multiple clinical, genetic, and radiologic features. Molecular genetic studies have identified more than 150 mutations of the COL1A1 and COL1A2 genes, which encode for type I procollagen. Various systemic treatments have been attempted; however, these interventions have been ineffective or inconclusive or are still experimental. Gene therapy has the potential to increase the synthesis of type I collagen in mild variants and to correct mutations in severe variants, but there are a great number of technical difficulties to overcome. The goals of treatment of OI are to maximize function, minimize deformity and disability, maintain comfort, achieve relative independence in activities of daily living, and enhance social integration. Attainment of these goals requires a team approach to tailor treatment needs to the severity of the disease and the age of the patient. Nonoperative management is the mainstay of orthopaedic treatment, with the goals of preventing and treating fractures and enhancing locomotion. Operative intervention is indicated for recurrent fractures or deformity that impairs function.

Intramedullary rodding in type III osteogenesis imperfecta. Effects on neuromotor development in 10 children

We studied retrospectively gross motor development and the impact of intramedullary rodding in 10 children with type III osteogenesis imperfecta (OI). There was a pronounced delay in motor development and the order in achieving gross motor milestones differed from the normal developmental sequence. Static milestones developed at an earlier stage than dynamic milestones. Intramedullary rodding of the lower extremities prior to the age of 3.5 years enhanced neuromotor development, especially regarding the milestones supported standing, rolling from prone to supine and crawling with abdomen on the floor. The different sequence in achieving gross motor milestones should have implications for future rehabilitation programs and for orthopedic surgery.