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

Retrograde femoral nailing for deformity correction and fracture treatment in osteogenesis imperfecta: clinical and radiological assessment of a novel technique

INTRODUCTION

Intramedullary anterograde femoral nailing is a standard treatment for femoral deformity and fracture in osteogenesis imperfecta (OI). This study evaluates the clinical and radiological outcomes of a novel retrograde femoral nailing technique.

METHODS

A retrospective analysis was performed on 31 patients with OI who underwent retrograde femoral nailing using Dubow-Bailey nails from 2004 to 2019. A total of 54 femurs were treated for femoral deformity or fracture by three senior surgeons, with a mean follow-up of 2.7 years. Clinical outcomes, including knee range of motion and pain, were assessed. Radiological outcomes included deformity angle (DA), neck shaft angle (NSA), mechanical lateral distal femoral angle (mLDFA), and nail positioning on AP and lateral X-rays. Potential complications, including hip osteonecrosis, distal femoral growth arrest, and infections, were also evaluated.

RESULTS

The procedure showed favorable outcomes, with no postoperative knee motion limitations or persistent pain. The mean pre-operative DA on AP and lateral views was 29° and 40°, respectively, with no residual deformity after surgery. The mean NSA and mLDFA were 132° and 101° before surgery, compared to 143° and 89° post-operatively. Nail alignment was optimal in 81% of the femurs, with proper positioning in both the distal epiphysis and femoral neck. No cases of hip osteonecrosis, distal femoral growth arrest, or infection were reported. Hardware migration occurred in seven cases.

CONCLUSION

Retrograde femoral nailing is a safe and effective technique for managing femoral deformities and fractures in OI.

Musculoskeletal System and Gait Characteristics in Patients with Osteogenesis imperfecta

OBJECTIVES

The aim of the study was to assess the muscoloskeletal system and spatiotemporal gait parameters of patients in three types of osteogenesis imperfecta.

DESIGN STUDY

Retrospective observational study.

SETTINGS

The Department of Rehabilitation, Children's Memorial Health Institute in Warsaw, Poland.

PARTICIPANTS

This study investigated individuals with various types of osteogenesis imperfecta: 33 with osteogenesis imperfecta I (aged 13.9), 16 with osteogenesis imperfecta III (aged 10.4), and 14 with osteogenesis imperfecta IV (aged, 15.8), as well as a reference group of 400 healthy individuals.

MAIN MEASURES

The musculoskeletal assessment included: medical record review, clinical evaluation, functional tests, long bone deformity assessment via clinical and X-ray examination, and objective gait analysis with the Vicon Motion Systems (Ltd, Oxford, UK).

RESULTS

The study revealed notable differences in clinical presentation, deformities within the musculoskeletal system, gait parameters across the various types of osteogenesis imperfecta (p < 0.001). The most affected gait parameters were: cadence, gait speed and step length. The greatest deformities of lower limbs and spine were presented in patients with osteogenesis imperfecta type III.

CONCLUSIONS

These findings are significant for understanding gait abnormalities in osteogenesis imperfecta patients and designing customized physiotherapy programs to help them participate fully in daily life. Improvement of muscle strength is one of the key for easier engagement in activities like walking or stair-climbing.

Surgical treatment of osteogenesis imperfecta: a summary of the incidence of femoral implant-related complications in children with Sillence type I, III and IV

PURPOSE

This study explored the incidence of IRCs used in the procedures of the femur in children with osteogenesis imperfecta (OI) and investigated the independent risk factors of IRCs.

METHODS

Three hundred eight-eight cases of surgical data about children with OI were included, who were treated with plate, elastic nail, Kirschner wire and telescopic rod. The choice of different procedures depended on the age of children, the status of femur and the availability of devices. Patient demographics and major IRCs were recorded to compare the outcomes of the four procedures. Then, Cox proportional hazard regression was used to analyse the independent risk factors of IRC, and subgroup analysis was applied to further verify the above results.

RESULTS

The total incidence of IRC in the four groups was 90.1% (191/212) for plate, 96.8% (30/31) for Kirschner wire, 87.7% (57/65) for elastic nail and 30.0% (24/80) for telescopic rod. The incidence of IRC in the telescopic rod was lower than that in plate, elastic nail and Kirschner wire (P < 0.001). Cox proportional hazard regression analysis confirmed that procedure was the independent risk factor of IRC (HR, 0.191; 95% CI, 0.126-0.288; P < 0.001), fracture (HR, 0.193; 95% CI, 0.109-0.344; P < 0.001) and deformity (HR, 0.086; 95% CI, 0.027-0.272; P < 0.001). In addition, age of surgery was the independent risk factor of fracture (HR, 0.916; 95% CI, 0.882-0.952; P < 0.001) and deformity (HR, 1.052; 95% CI, 1.008-1.098; P = 0.019). Subgroup analysis confirmed that age of surgery, gender, classification, preoperative state and angle did not affect the effect of telescopic rod on reducing the risk of IRCs.

CONCLUSIONS

In our cohort, lower incidence of IRCs was observed in telescopic rod group compared with plate, Kirschner wire and elastic nail. Procedure and age of surgery were independent risk factors of fracture. Likewise, procedure and age of surgery were independent risk factors of deformity, and procedure was independent risk factors of IRC.

TREATMENT OF OSTEOGENESIS IMPERFECTA USING THE FASSIER-DUVAL TELESCOPIC ROD

Objectives

This study aimed to assess the treatment of patients with Osteogenesis Imperfecta (OI) operated on with a telescopic Fassier-Duval (FD) rod in a querterenario hospital from 2010 to 2020.

Methods

We analyzed indication for surgical treatment, causes of reoperation, complications and the effectiveness of telescoping rod.

Results

The results were compared with the literature and with the same parameters from a previous study which a different telescopic rod developed by the same authors. This was a retrospective study based on the analysis of digital and radiographic clinical records. Fifteen patients with 21 FD rods were evaluated, most were used on the femur (18 rods or 85.7%), eight patients were female (53.3%), with a mean age of 10.47 (3.92 to 16.44) years, most of whom had type III Sillence (46.7%), with a mean follow-up of 5.22 (1.43 to 7.02) years. Seven rods (33.3%) had complications. The main indication was for fracture (57.1%). Regarding the ability to telescope, we observed that 15 rods (71.4%) followed the child's growth.

Conclusion

We had good results using FD rods, similar to the data found in the literature and the data obtained with our rod. Level of Evidence III,Retrospective comparative study .

Combinatorial Inhibition of Myostatin and Activin A Improves Femoral Bone Properties in the G610C Mouse Model of Osteogenesis Imperfecta

Osteogenesis imperfecta (OI) is a collagen-related bone disorder characterized by fragile osteopenic bone and muscle weakness. We have previously shown that the soluble activin receptor type IIB decoy (sActRIIB) molecule increases muscle mass and improves bone strength in the mild to moderate G610C mouse model of OI. The sActRIIB molecule binds multiple transforming growth factor-β (TGF-β) ligands, including myostatin and activin A. Here, we investigate the musculoskeletal effects of inhibiting activin A alone, myostatin alone, or both myostatin and activin A in wild-type (Wt) and heterozygous G610C (+/G610C) mice using specific monoclonal antibodies. Male and female Wt and +/G610C mice were treated twice weekly with intraperitoneal injections of monoclonal control antibody (Ctrl-Ab, Regn1945), anti-activin A antibody (ActA-Ab, Regn2476), anti-myostatin antibody (Mstn-Ab, Regn647), or both ActA-Ab and Mstn-Ab (Combo, Regn2476, and Regn647) from 5 to 16 weeks of age. Prior to euthanasia, whole body composition, metabolism and muscle force generation assessments were performed. Post euthanasia, hindlimb muscles were evaluated for mass, and femurs were evaluated for changes in microarchitecture and biomechanical strength using micro-computed tomography (μCT) and three-point bend analyses. ActA-Ab treatment minimally impacted the +/G610C musculoskeleton, and was detrimental to bone strength in male +/G610C mice. Mstn-Ab treatment, as previously reported, resulted in substantial increases in hindlimb muscle weights and overall body weights in Wt and male +/G610C mice, but had minimal skeletal impact in +/G610C mice. Conversely, the Combo treatment outperformed ActA-Ab alone or Mstn-Ab alone, consistently increasing hindlimb muscle and body weights regardless of sex or genotype and improving bone microarchitecture and strength in both male and female +/G610C and Wt mice. Combinatorial inhibition of activin A and myostatin more potently increased muscle mass and bone microarchitecture and strength than either antibody alone, recapturing most of the observed benefits of sActRIIB treatment in +/G610C mice. © 2022 American Society for Bone and Mineral Research (ASBMR).

Mechanical Analysis of Explanted Telescopic Rods in the Management of Osteogenesis Imperfecta: A Multicenter Study

BACKGROUND

Telescopic rods in the management of osteogenesis imperfecta fail frequently. This could be attributed to technical errors, rod design, and rod structure. We aimed to analyze the mechanical properties and tribology of explanted male and female components to identify effects of in vivo telescoping that may relate to observed patterns of successful telescoping or failure.

METHODS

Recruitment took place at 3 of the 4 English centers for osteogenesis imperfecta. Twenty-five rods explanted for growth or failure during revision to a new rod were analyzed in terms of clinical indication and prerevision imaging to identify if there was a technical mode of failure. Laboratory analysis was performed using optical and scanning electrical microscopy, radiograph diffraction analysis, hardness test, bending test, and energy-dispersive x-ray spectroscopy.

RESULTS

All implants tested were of high-grade stainless steel. Female components had inferior strength [mean Vickers hardness property (HV0.3) at 0.3 to 313 kg] in comparison to male components (HV0.3 406) due to different techniques of manufacture. Female rods also had a higher wear coefficient (7.89×10-12 m3/N/m3) than the male rods (6.46×10-12 m3/N/m3). Abrasive wear, shear deformation, scratches, and wear debris were identified in all rods. Male and female components displayed corrosion contributing to adhesive wear. Intraoperatively cut rods, particularly the female components, had irregular ends leading to more wear.

CONCLUSIONS

Current manufacturing techniques result in inferior material strength in female components compared with males, which combined with wear patterns is likely to lead to implant failure. Intraoperative cutting of rods may increase risk of failure due to wear. Considering techniques to improve strength as well as design in new implants may lead to better outcomes.

LEVELS OF EVIDENCE

Level IV-cross-sectional study.

Impact of Genetic and Pharmacologic Inhibition of Myostatin in a Murine Model of Osteogenesis Imperfecta

Osteogenesis imperfecta (OI) is a genetic connective tissue disorder characterized by compromised skeletal integrity, altered microarchitecture, and bone fragility. Current OI treatment strategies focus on bone antiresorptives and surgical intervention with limited effectiveness, and thus identifying alternative therapeutic options remains critical. Muscle is an important stimulus for bone formation. Myostatin, a TGF-β superfamily myokine, acts through ActRIIB to negatively regulate muscle growth. Recent studies demonstrated the potential benefit of myostatin inhibition with the soluble ActRIIB fusion protein on skeletal properties, although various OI mouse models exhibited variable skeletal responses. The genetic and clinical heterogeneity associated with OI, the lack of specificity of the ActRIIB decoy molecule for myostatin alone, and adverse events in human clinical trials further the need to clarify myostatin's therapeutic potential and role in skeletal integrity. In this study, we determined musculoskeletal outcomes of genetic myostatin deficiency and postnatal pharmacological myostatin inhibition by a monoclonal anti-myostatin antibody (Regn647) in the G610C mouse, a model of mild-moderate type I/IV human OI. In the postnatal study, 5-week-old wild-type and +/G610C male and female littermates were treated with Regn647 or a control antibody for 11 weeks or for 7 weeks followed by a 4-week treatment holiday. Inhibition of myostatin, whether genetically or pharmacologically, increased muscle mass regardless of OI genotype, although to varying degrees. Genetic myostatin deficiency increased hindlimb muscle weights by 6.9% to 34.4%, whereas pharmacological inhibition increased them by 13.5% to 29.6%. Female +/mstn +/G610C (Dbl.Het) mice tended to have similar trabecular and cortical bone parameters as Wt showing reversal of +/G610C characteristics but with minimal effect of +/mstn occurring in male mice. Pharmacologic myostatin inhibition failed to improve skeletal bone properties of male or female +/G610C mice, although skeletal microarchitectural and biomechanical improvements were observed in male wild-type mice. Four-week treatment holiday did not alter skeletal outcomes. © 2020 American Society for Bone and Mineral Research (ASBMR).

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.

Fassier-Duval Rod Failure: Is It Related to Positioning in the Distal Epiphysis?

BACKGROUND

The relationship between Fassier-Duval (FD) rod placement and rod failure rates has not previously been quantified.

METHODS

Retrospective review was conducted on patients with osteogenesis imperfecta treated with FD rods between 2005 and 2017. Age at first surgery, sex, Sillence type of osteogenesis imperfecta, bisphosphonate treatment, location of rod (side of body and specific bone), and dates of surgeries, radiographs, and rod failures were collected. C-arm images determined rod fixation within the distal epiphysis at the time of surgery. C-arm variables included rod deviation (percent deviation from the midline of the distal epiphysis) and anatomical direction of deviation (anterior/posterior and medial/lateral). X-ray images were examined for rod failure, which was defined as bending, pulling out of the physis, protrusion out of the bone, and/or failure to telescope. Cox proportional hazards regression models were used to compare failure rates with location of placement within the distal epiphysis allowing for clustering of the data by side (left or right) and bone (femur or tibia).

RESULTS

The cohort was 13 patients (11 female individuals and 2 male individuals) with a total of 66 rods and 75 surgeries. Mean time from the first surgery to the last follow-up visit was 8.9 years (SD=5 y). There was a 7% increase in hazard of failure per 1-mm increase in antero-posterior (AP) deviation [hazard ratio (HR), 1.07; 95% confidence interval (CI), 1.01-1.14; P=0.029)]. Similarly, there was a 9% increase in hazard of failure for every 1-mm increase in lateral deviation (HR, 1.09; 95% CI, 1.01-1.18; P=0.019). A 12% increase in hazard of failure per 10% increase in deviation from the midline for both AP and lateral radiograph views was also found, although this was only statistically significant for lateral deviation on the AP radiograph view (HR, 1.12; 95% CI, 1.01-1.25; P=0.030).

CONCLUSIONS

FD rod placement within the distal epiphysis has significant impact on increasing rod survival.

LEVEL OF EVIDENCE

Level III-therapeutic study.

Dislodgement of Telescopic Nail from the Epiphysis: A Case Report with an Analysis of Probable Mechanism

Telescopic nails such as Fassier-Duval (FD) nails have become the standard treatment for stabilizing long bones and correcting deformities in osteogenesis imperfecta (OI). These nails do not require repeat surgery for their replacement when the bones outgrow them. However, they are not completely free from complications. The prohibitive costs of the original implants have led to design modifications being introduced in locally manufactured telescopic nails. While these low-cost devices work well in most cases, they can lead to complications resulting from their design flaws. We present here the complication observed in a locally manufactured telescopic nail with a design similar to the FD nail. The male component of the nail got dislodged from the distal tibial epiphysis, resulting in its proximal migration. We discuss the probable mechanism of this complication and propose possible design changes that can bring down the rates of such incidences.

Fassier-Duval Rods are Associated With Superior Probability of Survival Compared With Static Implants in a Cohort of Children With Osteogenesis Imperfecta Deformities

BACKGROUND

The survival of Fassier-Duval (FD) telescoping rods as compared with static implants in children affected by osteogenesis imperfecta is not well characterized. The purpose of this study was to compare risk of lower extremity implant failure in FD rods versus static implants.

METHODS

Data were retrospectively collected from patients with osteogenesis imperfecta who underwent surgical treatment using either FD rods or static implants (Rush rods, flexible nails, or Steinmann pins) between 1995 and 2015. The timing of implant failure was the primary outcome variable of interest. Comparisons were limited to limbs with no previous history of implants. Cox-proportional hazards regression analyses were used to compare the hazard of implant failure across implants. Negative binomial regression analyses were used to compare the incidence of surgical procedures in the 2 implant groups.

RESULTS

The final cohort consisted of 64 limbs (n=21 patients). The static implant group (n=38) consisted of 24 Rush rods (63%), 14 flexible nails (37%), and 2 Steinmann pins (5%). The hazard of implant failure in the static implant group was 13.2 times [95% confidence interval (CI), 2.5-69.6; P=0.0024] the hazard of implant failure in the FD rod group. The hazard of implant failure among females was 4.8 (95% CI, 1.4-16.7; P=0.0125) times the hazard of implant failure among males. The total surgery rate in the static implant group was 7.8 (95% CI, 1.8-33.0; P=0.0056) times the total surgery rate in the FD group.

CONCLUSIONS

Among surgically naive limbs, FD rods were associated with significantly improved probability of survival compared with static implants.

LEVEL OF EVIDENCE

Level II-retrospective study.

The orthopaedic management of long bone deformities in genetically and acquired generalized bone weakening conditions

PURPOSE

Diseases such as osteogenesis imperfecta, fibrous dysplasia, hypophosphataemic rickets and others lead to soft and weak bones and long bone deformity in affected patients. As a consequence, these patients lose their walking capacity and functional abilities of the upper extremities as well.

METHODS

In combination with bisphosphonate treatment and physical rehabilitation programmes surgical interventions are being applied to correct and stabilize the deformed and less mechanically resistant long bones. Intramedullary devices, ideally with an elongating telescopic mechanism, have proven to be the most suitable implants.

RESULTS

The surgical correction and stabilization of deformed bones in weak bone diseases is very beneficial to the patients. Pain restriction, reduction of fracture events, minimization of consequences of traumatic events and falls have resulted in a significant functional improvement. The patients live on a better activity level with a much-improved individual independence. Despite a high complication and revision rate of the intramedullary rods the gain of quality of life outweighs these negative aspects by far.

CONCLUSION

Orthopaedic surgical treatment for deformed bones in patients with weak bone diseases has changed the life of the patients and plays a very important role in the disease management protocols.This paper was written under the guidance of the Study Group Genetics and Metabolic Diseases of the European Paediatric Orthopaedic Society.