Retrograde Application of Humerus Fassier-Duval Rod in Osteogenesis Imperfecta: A New Surgical Technique.

BACKGROUND: The aim of this study is to describe the technique of retrograde application of Fassier-Duval (FD) rod for the humerus in patients with osteogenesis imperfecta (OI). This technique was developed to overcome the downsides of the previously used techniques of humerus rodding. METHODS: The study was done at a tertiary care pediatric orthopaedic hospital from April 2014 to August 2021. Skeletally immature patients with OI who underwent retrograde FD rodding were included. This surgery was performed for humeral shaft fractures/bowing limited to the distal half of the bone to ensure appropriate stability of the fixation. Surgical technique of the procedure is described in detail. RESULTS: Six patients with OI, of which 2 (33.3%) had FD rodding bilaterally, were included. The mean age at rodding was 7.6±3.5 (range: 3 to 14) years. The mean duration of postoperative follow-up was 45.5±18.0 (range: 24 to 75) months. All patients had full healing of the fracture/osteotomy, with functional alignment of their humeri. No surgical complications were observed; however, 1 (12.5%) segment only had a traumatic humerus fracture following a fall that was associated with rod migration, occurring 60 months postoperatively. This was treated with a retrograde FD rodding again, with fracture augmentation with plate and screws. CONCLUSIONS: The retrograde FD rodding technique of the humerus in OI patients is relatively simple and preserves the soft tissue surrounding the shoulder joint, with favorable outcomes. Studies with larger sample size and long-term follow-up duration are needed. LEVEL OF EVIDENCE: Level IV-case series.

Osteogenesis Imperfecta-Who Needs Rodding Surgery?

PURPOSE OF REVIEW: The purpose of this review is to precise the indications for intramedullary rodding of long bones in osteogenesis imperfecta, the classic treatment for fractures and deformities in this condition. RECENT FINDINGS: The use of plates and screws alone is not recommended, but its use in conjunction with rodding is becoming more popular as demonstrated in recent literature. The different types of rods are reviewed and their advantages/disadvantages exposed. There is a clear advantage for telescopic rods in terms of incidence of revision surgery but complications are still to be expected. An interdisciplinary approach combining a medical treatment with a surgical correction of deformities as well as a rehabilitation program is the key for success in the treatment of osteogenesis imperfecta children.

Treatment of Femur Neck Fracture in Children with Osteogenesis Imperfecta: Two Case Reports.

CASE: We present 2 cases of femoral neck fracture (FNF) in patients with osteogenesis imperfecta (OI) with a previously placed intramedullary nail (IMN). Case 1: A 12-year-old girl who sustained a right FNF after spine surgery. Case 2: An 18-year-old boy who sustained a right FNF after IMN of the left side. Both patients underwent our modified surgical technique as described below. Both patients recovered well overall. CONCLUSIONS: FNF in patients with OI poses a significant challenge especially in the presence of an IMN. Here, we describe a surgical technique that provides stable fixation with a less stress riser effect by bypassing the screws and a previously placed nail.

Functional Outcome of Forearm Rodding in Children With Osteogenesis Imperfecta.

BACKGROUND: The impact of corrective forearm surgery on functional ability in children with osteogenesis imperfecta (OI) has not previously been reported. This study addresses this issue. METHODS: A retrospective chart review was conducted on 19 children with OI who underwent 22 corrective forearm procedures between 1996 and 2013. Functional ability was assessed preoperatively and every year postoperatively using the Pediatric Evaluation of Disability Inventory (PEDI). RESULTS: The mean PEDI self-care score increased by 6.8 (P=0.017) and the mean PEDI mobility score increased by 7.2 (P=0.020) at 1-year postsurgery. Functional gains were greater in moderate OI (types IV, V, and VI) than in severe OI (type III). Improved function was maintained in the majority of cases at a mean of 8.9 years postcorrection. CONCLUSIONS: Corrective forearm surgery in children with OI leads to improved functional ability. LEVEL OF EVIDENCE: Level IV.

Osteogenesis imperfecta.

Skeletal deformity and bone fragility are the hallmarks of the brittle bone dysplasia osteogenesis imperfecta. The diagnosis of osteogenesis imperfecta usually depends on family history and clinical presentation characterized by a fracture (or fractures) during the prenatal period, at birth or in early childhood; genetic tests can confirm diagnosis. Osteogenesis imperfecta is caused by dominant autosomal mutations in the type I collagen coding genes (COL1A1 and COL1A2) in about 85% of individuals, affecting collagen quantity or structure. In the past decade, (mostly) recessive, dominant and X-linked defects in a wide variety of genes encoding proteins involved in type I collagen synthesis, processing, secretion and post-translational modification, as well as in proteins that regulate the differentiation and activity of bone-forming cells have been shown to cause osteogenesis imperfecta. The large number of causative genes has complicated the classic classification of the disease, and although a new genetic classification system is widely used, it is still debated. Phenotypic manifestations in many organs, in addition to bone, are reported, such as abnormalities in the cardiovascular and pulmonary systems, skin fragility, muscle weakness, hearing loss and dentinogenesis imperfecta. Management involves surgical and medical treatment of skeletal abnormalities, and treatment of other complications. More innovative approaches based on gene and cell therapy, and signalling pathway alterations, are under investigation.

Hip Dysplasia in Children With Osteogenesis Imperfecta: Association With Collagen Type I C-Propeptide Mutations.

BACKGROUND: Osteogenesis imperfecta (OI) is a heritable skeletal disorder characterized by bone fragility and short stature that is usually due to mutations in 1 of the 2 genes that code for collagen type I α-chains. The association between hip dysplasia and OI has not been systematically investigated. In this single-center study, we retrospectively reviewed all cases of OI associated with hip dysplasia to describe clinical characteristics and the effect of therapy. METHODS: We reviewed the charts of 687 patients with OI who were seen at the Shriners Hospital for Children in Montreal between 1999 and 2013 to identify patients with a diagnosis of hip dysplasia. Clinical characteristics and the course after therapeutic interventions were extracted from the charts. RESULTS: Hip dysplasia was diagnosed in 8 hips of 5 patients (4 boys, 1 girl; age at diagnosis ranged between 3 wk and 27 mo old). The prevalence of hip dysplasia and OI was therefore 0.87% (per patient). In 4 of the 5 patients (80%), OI was caused by mutations affecting the C-propeptide of collagen type I, which is otherwise rare in OI. Among the 26 patients with C-propeptide mutations followed at our institution, 4 (15%) had hip dysplasia. Pavlik harness treatment was attempted in 2 patients (3 hips) but was not effective in either case and resulted in avascular necrosis of 1 hip. Femoral varus derotational shortening osteotomies using a telescopic rod were performed in all 8 hips along with a closed reduction in 4 hips and an open reduction in 4 hips. Concomitant pelvic osteotomies were performed in 2 hips (1 patient). Surgery resulted in redislocation of 1 hip; all other surgically treated hips remained reduced. CONCLUSIONS: Clinical screening for hip dysplasia is difficult in OI owing to the bowing of the proximal femur and the risk of causing fractures. OI patients with positive C-propeptide mutation should therefore be screened for hip dysplasia by use of ultrasound. Presence of a C-propeptide mutation appears to be a risk factor for hip dysplasia (80%). It appears that Pavlik harness treatment is not useful in children with OI. The usual treatment of children with OI who pull to stand or started walking with femoral deformity is femoral osteotomy and rodding. In case of associated hip dysplasia with a dislocation, open reduction of the hip and a possible concomitant pelvic osteotomy appears to be a valid management option. LEVEL OF EVIDENCE: Level IV.

Multidisciplinary Treatment of Severe Osteogenesis Imperfecta: Functional Outcomes at Skeletal Maturity.

OBJECTIVE: To determine the functional outcomes associated with long-term multidisciplinary treatment, intravenous bisphosphonate treatment, orthopedic surgery, and rehabilitation in children with severe osteogenesis imperfecta (OI) (diagnosed clinically as OI types III or IV). DESIGN: Retrospective study where outcomes were measured prospectively. SETTING: Pediatric orthopedic hospital. PARTICIPANTS: Adolescents (N=41; age range, 15-21y) with severe OI (OI type III: n=17; OI type IV: n=24) who had started therapy before the age of 6 years, had received treatment for at least 10 years, and had achieved final height. INTERVENTIONS: Intravenous bisphosphonate treatment, orthopedic surgery, and rehabilitation. MAIN OUTCOME MEASURE: Pediatric Evaluation of Disability Inventory. RESULTS: At the time of the last available follow-up examination, none of the individuals diagnosed with OI type III (most severely affected group) was able to ambulate without ambulation aids, whereas 20 (83%) patients with OI type IV were able to ambulate without ambulation aids. Regarding self-care, we specifically assessed 8 skills that we deemed essential for living independently (grooming; dressing; toileting; bed, chair, toilet, tub, and car transfers). Only 6 (35%) of the youths with OI type III were able to complete all 8 items, whereas 23 (96%) individuals with OI type IV managed to perform all tasks. Teens with OI type III often needed assistance for the transfer to toilet, tub, and car and for personal hygiene and clothing management associated with toileting, usually because of limitations in upper-extremity function. CONCLUSIONS: These observations suggest that further improvements in the functional status of the most severely affected children with OI are contingent on advances in the clinical management of upper-extremity issues.

Intravenous Bisphosphonate Therapy of Young Children With Osteogenesis Imperfecta: Skeletal Findings During Follow Up Throughout the Growing Years.

Cyclical intravenous bisphosphonate therapy is widely used to treat children with osteogenesis imperfecta (OI), but little is known about long-term treatment outcomes. We therefore reviewed 37 children with OI (OI type I, n = 1; OI type III, n = 14; and OI type IV, n = 22) who started intravenous bisphosphonate therapy before 5 years of age (median 2.2 years; range, 0.1 to 4.8 years), and who had a subsequent follow-up period of at least 10 years (median 14.8 years; range, 10.7 to 18.2 years), during which they had received intravenous bisphosphonate treatment (pamidronate or zoledronic acid) for at least 6 years. During the observation period, the mean lumbar spine areal bone mineral density Z-score increased from -6.6 (SD 3.1) to -3.0 (SD 1.8), and weight Z-score increased from -2.3 (SD 1.5) to -1.7 (SD 1.7) (p < 0.001 and p = 0.008). At the time of the last assessment, patients with OI type IV had significantly higher height Z-scores than a control group of patients matched for age, gender, and OI type who had not received bisphosphonates. Patients had a median of six femur fractures (range, 0 to 18) and five tibia fractures (range, 0 to 17) during the follow-up period. At baseline, 35% of vertebra were affected by compression fractures, whereas only 6% of vertebra appeared compressed at the last evaluation (p < 0.001), indicating vertebral reshaping during growth. Spinal fusion surgery was performed in 16 patients (43%). Among the 21 patients who did not have spinal fusion surgery, 13 had scoliosis with a curvature ranging from 10 to 56 degrees. In conclusion, long-term intravenous bisphosphonate therapy was associated with higher Z-scores for lumbar spine areal bone mineral density and vertebral reshaping, but long-bone fracture rates were still high and the majority of patients developed scoliosis.

Homozygosity for frameshift mutations in XYLT2 result in a spondylo-ocular syndrome with bone fragility, cataracts, and hearing defects.

Heparan and chondroitin/dermatan sulfated proteoglycans have a wide range of roles in cellular and tissue homeostasis including growth factor function, morphogen gradient formation, and co-receptor activity. Proteoglycan assembly initiates with a xylose monosaccharide covalently attached by either xylosyltransferase I or II. Three individuals from two families were found that exhibited similar phenotypes. The index case subjects were two brothers, individuals 1 and 2, who presented with osteoporosis, cataracts, sensorineural hearing loss, and mild learning defects. Whole exome sequence analyses showed that both individuals had a homozygous c.692dup mutation (GenBank: NM_022167.3) in the xylosyltransferase II locus (XYLT2) (MIM: 608125), causing reduced XYLT2 mRNA and low circulating xylosyltransferase (XylT) activity. In an unrelated boy (individual 3) from the second family, we noted low serum XylT activity. Sanger sequencing of XYLT2 in this individual revealed a c.520del mutation in exon 2 that resulted in a frameshift and premature stop codon (p.Ala174Profs(∗)35). Fibroblasts from individuals 1 and 2 showed a range of defects including reduced XylT activity, GAG incorporation of (35)SO4, and heparan sulfate proteoglycan assembly. These studies demonstrate that human XylT2 deficiency results in vertebral compression fractures, sensorineural hearing loss, eye defects, and heart defects, a phenotype that is similar to the autosomal-recessive disorder spondylo-ocular syndrome of unknown cause. This phenotype is different from what has been reported in individuals with other linker enzyme deficiencies. These studies illustrate that the cells of the lens, retina, heart muscle, inner ear, and bone are dependent on XylT2 for proteoglycan assembly in humans.

Osteotomy Healing in Children With Osteogenesis Imperfecta Receiving Bisphosphonate Treatment.

A decade ago our group had reported that osteotomy healing was commonly delayed in children with moderate to severe osteogenesis imperfecta (OI) who were treated with intravenous pamidronate infusions. We subsequently maintained a bisphosphonate infusion-free interval of 4 months after osteotomy and changed the surgical approach (use of an osteotome instead of a power saw). In addition, zoledronic acid has become the standard intravenous bisphosphonate for treatment of OI at our institution. In the present study, we compared osteotomy healing before and after these changes were instituted. We evaluated bone healing post-osteotomy on standard radiographs after 261 intramedullary rodding procedures involving osteotomies (139 femur, 112 tibia) in 110 patients (age at surgery 1.2 to 20.4 years). Delayed healing was diagnosed when the osteotomy line was visible 12 months after the event. We observed delayed bone healing after 48 of the 114 osteotomies (42%) performed with the new approach, and in 106 of the 147 osteotomies (72%) using the previous approach (p = 0.001). The odds for delayed osteotomy healing were significantly lower with the new approach even after adjustment for age, sex, height Z-score, weight Z-score, OI type, and bone involved (odds ratio = 0.17; 95% confidence interval 0.16-0.47). Thus, delayed osteotomy healing occurred less frequently in the past 10 years than in the decade before that. It is likely that this improved result is attributable to the implemented changes in both medical and surgical management.

Topological mapping of BRIL reveals a type II orientation and effects of osteogenesis imperfecta mutations on its cellular destination.

BRIL/IFITM5 is a membrane protein present almost exclusively in osteoblasts, which is believed to adopt a type III (N-out/C-out) topology. Mutations in IFITM5 cause OI type V, but the characteristics of the mutant protein and the mechanism involved are still unknown. The purpose of the current study was to re-assess the topology, localization, and biochemical properties of BRIL and compare it to the OI type V mutant in MC3T3 osteoblasts. Immunofluorescence labeling was performed with antibodies directed against BRIL N- or C-terminus. In intact cells, BRIL labeling was conspicuously detected at the plasma membrane only with the anti-C antibody. Detection of BRIL N-terminus was only possible after cell permeabilization, revealing both plasma membrane and Golgi labeling. Trypsinization of live cells expressing BRIL only cleaved off the C-terminus, confirming that it is a type II protein and that its N-terminus is intracellular. A truncated form of BRIL lacking the last 18 residues did not appear to affect localization, whereas mutation of a single leucine to arginine within the transmembrane segment abolished plasma membrane targeting. BRIL is first targeted to the endoplasmic reticulum as the entry point to the secretory pathway and rapidly traffics to the Golgi via a COPII-dependent pathway. BRIL was found to be palmitoylated and two conserved cysteine residues (C52 and C53) were critical for targeting to the plasma membrane. The OI type V mutant BRIL, having a five residue extension (MALEP) at its N-terminus, presented with exactly the same topological and biochemical characteristics as wild type BRIL. In contrast, the S42 > L mutant BRIL was trapped intracellularly in the Golgi. BRIL proteins and transcripts were equally detected in bone from a patient with OI type V, suggesting that the cause of the disease is a gain of function mediated by a faulty intracellular activity of the mutant BRIL.

Correction of proximal tibial recurvatum using the Ilizarov technique.

BACKGROUND: Genu recurvatum is a debilitating deformity of the knee that can progress during growth and lead to significant deformity if left untreated. Recurvatum can be osseous, ligamentous, or mixed. Osseous genu recurvatum is most often due to asymmetrical growth arrest of the proximal tibial physis affecting primarily the tibial tubercle. Several methods have been described in the literature regarding the correction of this deformity; nevertheless, there is a paucity of knowledge of the correction of proximal tibial recurvatum using the Ilizarov technique. METHODS: A retrospective chart and radiographic review of all patients treated by distraction osteogenesis with angular correction distal to the tibial tubercle using an Ilizarov external fixator was performed. A total of 9 patients were treated during the study period and the average age at the time of surgery was 14.3 years (range, 7-16 y). There were 3 female patients and 6 male patients. Four cases were due to deformity secondary to trauma and the treatment thereof, 2 patients had spondyloepiphyseal dysplasia, and 3 patients had unknown etiology. The angle of recurvatum (RG) and the angle of tilt of the tibial plateau (RT) preoperatively measured 28 degrees (range, 18 to 32 degrees) and 69 degrees (range, 60 to 82 degrees), respectively. At final follow-up, the RG and RT measured 7 degress (range, 4 to 12 degrees) and 93 degrees (range, 86 to 100 degress), respectively. Using the scoring system of Lecuire and colleagues, the overall results were good to excellent at a mean follow-up of 4.4 years. CONCLUSIONS: Correction of osseous proximal tibial recurvatum by the Ilizarov method, allows obtaining an improved sagittal mechanical axis in the lower extremity.

Fassier-Duval femoral rodding in children with osteogenesis imperfecta receiving bisphosphonates: functional outcomes at one year.

PURPOSE: To examine the functional outcomes of children with osteogenesis imperfecta (OI) following initial Fassier-Duval (FD) rodding to the femur at 1 year, and to determine which factors are associated with change in gross motor function, ambulation, and functional performance. METHODS: Approval from our Institutional Review Board was obtained. A retrospective chart review identified 60 children (28 males, 32 females) with OI who underwent initial FD femoral rodding (101 rods) and who were receiving bisphosphonates. The mean age of the children was 3 years, 11 months at the initial femoral FD rodding. Two had type I OI, 30 type III, 27 type IV, and one type VI. The maximum length of follow-up was 4 years. Telescoping FD rods were used for the femurs, with surgeries performed one leg at a time, with a 1-week interval. The active range of motion (AROM) of the hips and knees in flexion was measured 4-5 weeks post-initial rodding. Outcomes on the Gillette Functional Assessment Questionnaire (FAQ) Ambulation Scale, the Gross Motor Function Measure (GMFM), and the Pediatric Evaluation of Disability Inventory (PEDI) were compared pre-operatively and at 1 year post-surgery using t-tests and multivariate linear regression. RESULTS: Pre-operatively, the mean FAQ score was 2.0, and this increased to 5.8 at 1 year post-surgery. Statistically significant improvements (P ≤ 0.05) were found on the FAQ, crawling, standing, walking and running, and total domains of the GMFM, and PEDI mobility and self-care from baseline to 1 year. The results from the multivariate linear regression indicate that older age (P = 0.0045) and higher weight (P = 0.0164) are significantly associated with lower scores in the self-care domain of the PEDI, and that OI type III compared to type IV is significantly associated (P = 0.0457) with greater improvement on the crawling domain of the GMFM. Higher weight was also associated (P = 0.0289) with lower scores in the standing domain of the GMFM, as well as with the total GMFM score (P = 0.0398). CONCLUSIONS: Our findings indicate that initial FD femoral rodding resulted in benefits in ambulation, gross motor function, self-care, and mobility for children with OI beyond physiological expectations due to developmental growth. FD rodding is a procedure which can improve the overall mobility in children with OI with significant femoral deformities.

Enhancement of difficult nonunion in children with osteogenic protein-1 (OP-1): early experience.

UNLABELLED: Numerous studies have described the use of osteogenic protein-1 (OP-1) in adults, but there are few reports in children. The objectives of this short-term followup cohort study were (1) to examine clinical and radiographic healing of persistent nonunions after OP-1 application in children; and (2) to determine the safety of OP-1 use in this sample. Clinical healing was defined by absence of pain and tenderness at the nonunion site and the ability to fully weight bear on the affected limb. Radiographic healing was determined by bony bridging of the nonunion site in at least one view. Safety was defined as the absence of major adverse events, including allergic reactions, infections, local inflammatory reactions, and heterotopic ossification. OP-1 was used in 19 patients who had an operative procedure for the bridging of persistent nonunions between 1999 and 2007. The mean age was 11.6 years (range, 4.8-20.3 years). Thirteen patients had persistent nonunion after one or more previous surgeries, prior to the initial OP-1 application. A single dose of 3.5 mg of OP-1 mixed with 1 g of Type I bovine collagen was applied to 23 sites of 19 patients. Three patients received additional OP-1 applications. Healing occurred clinically and radiographically in 17 of the 23 sites. Complications included four superficial pin site infections, one deep infection, and two fractures. No major local adverse event related to OP-1 application was noted in our sample. Our findings suggest OP-1 stimulates healing of persistent nonunions without major adverse events in our patient population. LEVEL OF EVIDENCE: Level IV, case series. See the guidelines online for a complete description of levels of evidence.

Results and complications of a surgical technique for correction of coxa vara in children with osteopenic bones.

BACKGROUND: Surgical correction of coxa vara in children with osteopenic bone diseases could be very challenging. In this study, we describe a modified surgical technique for the correction of coxa vara in children with bone fragility. We also report the results and complications of this technique in 16 children (21 coxa vara) with osteopenic bone diseases. METHODS: Charts, clinic notes, and radiology images of 16 patients (21 hips) who had a proximal femoral osteotomy for the treatment of coxa vara in osteogenesis imperfecta (18 hips) and fibrous dysplasia (3 hips) in our institution between 1996 and 2005 were reviewed. The modified surgery involved an intertrochanteric osteotomy and the use of Kirshner wires and intramedullary rods. Neck-shaft angle, Hilgenreiner-epiphyseal angle, and head-shaft angle were assessed at preoperative, postoperative, and final follow-up. RESULTS: The average age at surgery was 8.3 years (range, 3.3-15.8 years). The average correction of the neck-shaft angle was from 84.6 to 114.4 degrees, and for the Hilgenreiner-epiphyseal angle, it was from 67.7 to 42 degrees at final follow-up. All osteotomies were healed at 3 months postoperatively. The mean follow-up was 4.29 years (range, 1.70-8.12 years). The average improvement in abduction and external rotation of the hips was 14 and 15 degrees, respectively. There were no cases of infection and 2 cases (12%) of implant-related complications. One patient with fibrous dysplasia needed replacement of the intramedullary rod and additional distal femoral osteotomy 1 week postsurgery. In another patient, the intramedullary rod had migrated proximally, which was corrected 5 months postsurgery by advancing the rod distally. CONCLUSION: Results suggest that this surgical technique provides satisfactory correction of coxa vara in children with osteopenic bone diseases. CLINICAL RELEVANCE: The described surgical technique used to correct coxa vara is reproducible and safe and has few complications. Furthermore, the size of the implants used allows surgery to be performed in very young children.

Radial head dislocation and subluxation in osteogenesis imperfecta.

BACKGROUND: Upper limb deformity in children with osteogenesis imperfecta may substantially impair function. The aims of this retrospective work were to study the prevalence of radial head malalignment (dislocation or subluxation) in different types of osteogenesis imperfecta and to identify factors linked to it. METHODS: We assessed 489 upper limbs from 254 patients (with a mean age of 9.6 years and including 130 female patients) who had various types of osteogenesis imperfecta. Radiographs representing a single time-point for each patient were assessed for the presence and direction of radial head malalignment and associated abnormalities (dysplasia of the capitellum or of the radial head or neck, calcification of the interosseous membrane, or radioulnar synostosis). Deformations of the humerus, radius, and ulna were assessed with regard to location, direction, and magnitude. The forearm range of motion in pronation and supination and the hand grip force were measured in a subset of patients. RESULTS: We observed radial head dislocation or subluxation in forty-four and thirty-nine upper extremities, respectively. The frequency of radial head malalignment was significantly higher in type-V osteogenesis imperfecta (86%) than in the other types (0% to 29%) (p < 0.001). Dysplasia of the humeral capitellum, radial head, or radial neck was associated with malalignment in all types of osteogenesis imperfecta, with the exception of capitellum dysplasia in type V. Malalignment in type V was associated with calcification of the interosseous membrane, an abnormality that was specific for type V. In the other osteogenesis imperfecta types, malalignment was commonly linked with radial and ulnar deformation and was associated with decreased forearm range of motion in supination and pronation and a lower grip force. CONCLUSIONS: Radial head malalignment is common in osteogenesis imperfecta, especially in type V. Malalignment is associated with bowing characteristics and impaired function of the upper limb. These findings may provide support for surgical correction of radial and ulnar bowing in selected patients with osteogenesis imperfecta.

High prevalence of coxa vara in patients with severe osteogenesis imperfecta.

The purpose of this study was to determine the incidence and clinical presentation of coxa vara in 283 patients with osteogenesis imperfecta (OI). The charts and X-rays of 150 girls and 133 boys with OI were reviewed. The patients were classified according to the Sillence classification modified by Glorieux: 94 type I, 90 type IV, 67 type III, 18 type V, 10 type VI, and 4 type VII. The mean age was 9.4 years (range 0.3-23.3). Twenty-nine patients (10.2%) had coxa vara (23 left and 20 right). Fifty-five percent of them were type III, 24% type IV, 13.8% type VI, and 3.4% each of types V and VII. The incidence of coxa vara was 6% in type V, 8% in type IV, 24% in type III, 25% in type VII, and 40% in type VI (P < 0.001 for difference between types I, III, and IV). The mean neck-shaft angle was 99 degrees (range 80-110 degrees), the average head-shaft angle was 104 degrees (range 90-120 degrees), and the mean Hilgenreiner-epiphyseal angle was 68 degrees (range 40-90 degrees). Twenty-five patients (36 hips) had previous femoral rodding before diagnosis and seven hips (all type III) had no history of rodding. Abduction and internal rotation of the hip joints were restricted in all patients with this deformity. All children with coxa vara had a Trendelenburg gait. In conclusion, coxa vara in OI is not rare, especially in severe forms of the disease. Regular clinical and radiologic follow-up is indicated in children with previous femoral rodding and in severely affected children, particularly those with OI type III.

Delayed osteotomy but not fracture healing in pediatric osteogenesis imperfecta patients receiving pamidronate.

UNLABELLED: This study evaluated factors influencing fracture (n = 197) and osteotomy (n = 200) healing in children with moderate to severe OI. Pamidronate treatment was associated with delayed healing after osteotomy, but not after fracture. The data suggest that both pamidronate and mechanical factors influence bone healing in this cohort. INTRODUCTION: Intravenous pamidronate is widely used to treat children with moderate to severe osteogenesis imperfecta (OI). However, the effect of this treatment on bone healing is not well characterized. We therefore retrospectively analyzed the healing of lower limb fractures and osteotomies in children with moderate to severe OI, both before and after the start of pamidronate treatment. MATERIALS AND METHODS: Bone healing was evaluated on standard radiographs after 197 lower limb fractures (132 femur and 65 tibia) in 82 patients (age at fracture, 0.0-19.9 years) and 200 intramedullary rodding procedures in 79 patients (age at surgery, 1.2-19.8 years). Delayed healing was diagnosed when a fracture or osteotomy line was at least partially visible 12 months after the event. RESULTS: Delayed fracture healing was observed more frequently during than before pamidronate treatment. However, the effect of pamidronate was no longer significant when age differences were taken into account (odds ratio [OR], 1.76; 95% CI, 0.61-5.10). Better mobility status was a strong independent predictor of delayed healing after fractures that occurred during pamidronate treatment. After osteotomies, delayed healing was more frequent when pamidronate had been started before surgery (OR, 7.29; 95% CI, 2.62-20.3), and this effect persisted after adjustment for multiple confounders. During pamidronate treatment, older age (OR per year of age, 1.25; 95% CI, 1.06-1.47) and osteotomy of the tibia (OR, 3.51; 95% CI, 1.57-7.82) were independent predictors of delayed healing. CONCLUSIONS: This study suggests that pamidronate therapy is associated with delayed healing of osteotomy sites after intramedullary rodding procedures. Better mobility status, but not pamidronate treatment, seems to be predictive of delayed healing after fractures.

Total hip arthroplasty in patients younger than 21 years: a minimum, 10-year follow-up.

INTRODUCTION: To evaluate the function, radiographic results and implant survival in patients younger than 21 years at the time of operation and with at least a 10-year follow-up, we reviewed the course of young adults who underwent total hip arthroplasty at McGill University Health Centre. PATIENTS AND METHODS: Twelve patients (16 hips) met the criteria for inclusion in this study. They ranged in age from 10-20 years (median 16.5 yr). One patient (1 hip) died 5 years after the index surgery and was excluded from the study. Functional results were measured by the Harris hip score, and radiographs of surviving implants were assessed for radiolucencies, osteolysis and eccentric polyethylene wear. RESULTS: Eleven arthroplasties were cementless, 2 were hybrid and 2 were cemented. At follow-up ranging from 10 to 25 years (mean 13.6 yr), the Harris hip score ranged from 34.2-97.2 (mean 64.5). Four (26%) acetabular components were revised and (at the time of writing) 1 required revision. Only 1 (7%) femoral stem was revised. Radiographically, there was a high prevalence of eccentric polyethylene wear, but none of the surviving implants were found to be loose. Overall, 67% (10 of 15) of the total hip arthroplasties continued to function well at a mean of 13.6 years postoperatively. CONCLUSIONS: Total hip arthroplasty remains a reasonable option in adolescence and early adulthood in selected patients with severe debility from multiple joint disease. Polyethylene wear is a particularly significant problem in this group of active young people.