Mechanistic insights into the cellular effects of a novel FN1 variant associated with a spondylometaphyseal dysplasia.

Spondylometaphyseal dysplasia (SMD) is characterized by developmental changes in long bones and vertebrae. It has large phenotypic diversity and multiple genetic causes, including a recent link to novel variants in the extracellular matrix (ECM) protein fibronectin (FN), a regulator of ECM assembly and key link between the ECM and proper cell function. We identified a patient with a unique SMD, similar to SMD with corner fractures. The patient has been followed over 19 years and presents with short stature, genu varum, kyphoscoliosis, and pectus carinatum. Radiography shows metaphyseal changes that resolved over time, vertebral changes, and capitular avascular necrosis. Whole exome sequencing identified a novel heterozygous FN1 variant (p.Cys97Trp). Using mass spectroscopy, mutant FN was detected in plasma and in culture medium of primary dermal fibroblasts isolated from the patient, but mutant protein was much less abundant than wild-type FN. Immunofluorescence and immunoblotting analyses show that mutant fibroblasts assemble significantly lower amounts of FN matrix than wild-type cells, and mutant FN was preferentially retained within the endoplasmic reticulum. This work highlights the importance of FN in skeletal development, and its potential role in the pathogenesis of a subtype of SMD.

Delayed ossification and abnormal development of tarsal bones in idiopathic clubfoot: should it affect bracing protocol when using the Ponseti method?

PURPOSE: To point out the need to take into account the dysplastic nature of tarsal bones when treating idiopathic clubfoot (CF). METHODS: Review the published evidence on the developmental abnormalities of tarsal bones in idiopathic CF. RESULTS: The literature review provides abundant proof of the existence of delayed appearance and slower development of ossification centres of tarsal bones in idiopathic clubfoot. CONCLUSION: Gentle manipulations and casting are the cornerstone of the Ponseti method. The biological response of all foot elements is critical for a successful outcome. Delayed ossification and abnormal development of tarsal bones in idiopathic CF may affect the results. Development of a personalized tailored bracing protocol based on severity assessment and response to casting treatment will improve results and quality of care in CF management. LEVEL OF EVIDENCE: V.

The significance of foot length at the initiation of the Ponseti method: a prospective study.

OBJECTIVES: We sought to evaluate foot length (FL) and forefoot circumference (FC) and their impact on the severity of idiopathic clubfoot (CF) and results of treatment. We hypothesized that a smaller foot size at birth that represents a lesser than term newborn may affect the response of the CF to the treatment. METHODS: We conducted a prospective study documenting FL and FC of all neonates presented with idiopathic CF. Additional demographic information was collected. Outcome measures were number of casts needed for correction, need for recasting, additional surgery and functional score. RESULTS: In all, 52 children with 73 CF with a minimum mean follow-up of two years (2.0 to 5.6; sd 1.08) were evaluated. Mean gestational age was 38.63 weeks and mean birth weight (BW) was 3184 g. The mean FL at presentation was 74 mm (5.70 to 9.00), initial Pirani score was 5.5 (2.5 to 6.0) while number of casts was 6.9 (4.0 to 11.0). The FL was significantly correlated both to initial Pirani score (r = -0.35; p < 0.01) and number of casts (r = -0.33; p < 0.05). Positive correlation was found between the number of casts to Pirani score and number of additional procedures (r = 0.39; r = 0.36; p < 0.01, respectively). A foot size of up to 8 cm, needed 7.3 casts (4 to 7) compared with a FL of 8 cm or longer who needed 4.7 casts (4 to 6; t = 7.11; p < 0.001). CONCLUSION: FL is a simple approach to identify preterm babies. It can be used as part of the initial evaluation of CF and help in predicting the course of treatment. We recommend adding FL to the existing classification. LEVEL OF EVIDENCE: I - Prognostic study.

Congenital talipes equinovarus: a systematic review of relapse as a primary outcome of the Ponseti method.

AIMS: The Ponseti method is the benchmark treatment for the correction of clubfoot. The primary rate of correction is very high, but outcome further down the treatment pathway is less predictable. Several methods of assessing severity at presentation have been reported. Classification later in the course of treatment is more challenging. This systematic review considers the outcome of the Ponseti method in terms of relapse and determines how clubfoot is assessed at presentation, correction, and relapse. PATIENTS AND METHODS: A prospectively registered systematic review was carried out according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies that reported idiopathic clubfoot treated by the Ponseti method between 1 January 2012 and 31 May 2017 were included. The data extracted included demographics, Ponseti methodology, assessment methods, and rates of relapse and surgery. RESULTS: A total of 84 studies were included (7335 patients, 10 535 clubfeet). The relapse rate varied between 1.9% and 45%. The rates of relapse and major surgery (1.4% to 53.3%) and minor surgery (0.6% to 48.8%) both increased with follow-up time. There was high variability in the assessment methods used across timepoints; only 57% of the studies defined relapse. Pirani scoring was the method most often used. CONCLUSION: Recurrence and further surgical intervention in idiopathic clubfoot increases with the duration of follow-up. The corrected and the relapsed foot are poorly defined, which contributes to variability in outcome. The results suggest that a consensus for a definition of relapse is needed. Cite this article: Bone Joint J 2019;101-B:639-645.

Does idiopathic congenital talipes equinovarus have an impact on attainment of developmental milestones? A multicentre international study.

PURPOSE: The Ponseti method is a well-established approach to treating clubfoot. Potentially, both the underlying pathology and adherence to post-correction bracing can affect lower limb function and age of independent standing and walking. This cohort study investigates the age at which infants with idiopathic clubfoot treated using the Ponseti method achieved three selected developmental milestones and whether or not this correlated with treatment compliance. METHODS: A prospectively collected database from four centres was visited. Inclusion criteria were patients with idiopathic clubfoot with no comorbidities or prior treatment. Age at attainment of independent standing, walking, nocturnal continence was compared across three groups: I) congenital talipes equinovarus (CTEV) children compliant with treatment; II) CTEV children non-compliant with treatment; and III) typically-developed siblings. Minimum follow-up was five years. RESULTS: In all, 130 patients (198 feet) fitted the inclusion criteria: 43:87 (F:M). Standing was achieved by a mean 12.0 months in group I (sd 2.50); 12.0 months (sd 2.0) in II and ten months (sd 3.0) in III. Walking was achieved by a mean 15 months (sd 4.0) in group I, 14 months (sd 1.75) in II and 12 months (sd 3) in III, respectively. Both the compliant and non-compliant CTEV children were significantly slower at achieving standing and walking compared to sibling controls (p < 0.0001). There was no significant difference between age of nocturnal continence between the three groups. CONCLUSION: Infants with idiopathic clubfoot treated according to the Ponseti method achieve independent standing and walking approximately two months later than their typically-developed siblings. The delay is not related to the use of the foot abduction brace. LEVEL OF EVIDENCE: III.

Growth modulation in idiopathic angular knee deformities: is it predictable?

PURPOSE: To evaluate the temporal and spatial sequence of events following temporal hemiepiphysiodesis in idiopathic knee varus/valgus. METHODS: This is a retrospective multicentre study on 372 physes in 206 patients. The average rate of correction (ROC) was calculated; univariate and multivariate analysis were performed. RESULTS: In all, 92% of the femoral physes were followed for more than one year/reached skeletal maturity. Of those, 93% were corrected to a mechanical lateral distal femoral angle (mLDFA) of 85° to 89°; 2% did not, while 5% were over-corrected. A total of 92% of the tibial physes were followed for more than one year/reached skeletal maturity. Of those, 92% were corrected to a mechanical medial proximal tibial angle (mMPTA) of 85° to 89°; 2% did not, while 6% were over-corrected. Factors significantly influencing success and ROC were age, direction and magnitude of deformity. Femoral ROC was significantly faster than tibial ROC: 0.85° versus 0.78°/month, respectively (p = 0.05). Femoral valgus ROC was significantly faster than varus ROC: 0.90° versus 0.77°/month, respectively (p = 0.04). A constant was derived to calculate the amount of correction. Significant correlation was found between calculated and actual mLDFA in valgus deformity during the first year (r = 0.58 to 0.87, p < 0.01). Calculated mLDFA of varus deformity did not correlate with actual mLDFA. Significant correlation was found when calculating mMPTA correction in all deformities. CONCLUSIONS: Femur corrects faster than tibia; valgus femoral deformities are corrected faster than varus. Valgus correction in the distal femur/proximal tibia as well as varus correction in the tibia in idiopathic patients is highly predictable. The constant derived is the first tool which enables predicting and monitoring amount of correction in hemiepiphysiodesis when correcting angular deformities around the knee. LEVEL OF EVIDENCE: IV.

V osteotomy and Ilizarov technique for residual idiopathic or neurogenic clubfeet.

PURPOSE: To report the treatment outcomes of V osteotomy and Ilizarov technique for residual idiopathic or neurogenic clubfeet. METHODS: 13 patients (14 feet) aged 8 to 18 years underwent V osteotomy via the calcaneus and talus, followed by gradual distraction of soft tissue and bone for foot reconstruction. Eight of the clubfeet were idiopathic and had undergone previous surgeries. The remaining 6 were neurogenic and their pathologies were: Charcot-Marie-Tooth disease (n=2), myelomeningocele (n=2), neurofibromatosis (n=1), and distal arthrogryposis (n=1). Three of them had undergone previous surgeries. The Ilizarov frames were retained for 3 to 6 months and the patients were followed up for 1.8 to 8.9 years. Range of movement of the ankle and foot, appearance and position, gait, pain, function, and patient satisfaction were assessed according to the modified clubfoot grading system. The talo-1st metatarsal angle was measured on anteroposterior radiographs. RESULTS: Scores associated with the appearance and position of the foot, and thus patient satisfaction were significantly improved, but not for range of movement, pain, and function. The mean preoperative and final talo-1st metatarsal angles were 39.7 and 8.7 degrees, respectively (p<0.01). Ten feet achieved the plantigrade position, one had residual equinus, and 3 had residual adduction and supination. CONCLUSION: Patient satisfaction improved significantly despite no major improvement in pain, function, and range of movement of the ankle and foot. This reflects the importance of the appearance and position of the foot, and justifies the decision to undergo this long and demanding procedure.

T1-weighted MR imaging of bone marrow pattern in children with adolescent idiopathic scoliosis: a preliminary study.

PURPOSE: Distinct normal physiological patterns of fat conversion in vertebrae were described both for children and adults. Our aim was to evaluate the T1-weighted bone marrow pattern of the vertebral bodies in various sites along the scoliotic spine of children with adolescent idiopathic scoliosis (AIS). METHODS: We retrospectively evaluated spine MRI studies of children with AIS. Scoliosis radiographs were assessed for type of curvature according to the Lenke classification. A paediatric neuroradiologist assessed the T1-weighted signal of vertebral bodies in comparison with the adjacent disc and distinct patterns of fatty conversion within the apical and stable vertebral bodies. Statistical assessment was performed. RESULTS: MRI study of the spines of 75 children with AIS were assessed, 59 (79%) of whom were female, with an age range of nine to 19 years. The relative overall T1-weighted signal intensity of the vertebral body bone marrow relative to the intervertebral disc was hyperintense in 76% and isointense in 24%. Fatty conversion grade of the stable vertebra was higher than the apex vertebra (p = 0.0001). A significant tendency to have more advanced fat conversion patterns in the apex vertebra up to age 13.5 years old compared with adolescents above that (p = 0.015) was seen. CONCLUSION: This preliminary study suggests a different pattern of bone marrow conversion in AIS from the normal physiologic pattern described in the literature. Whether these changes are secondary to the biomechanics of the curved spine or may suggest that bone marrow maturation rate and content have a role in the pathogenesis of AIS remains to be further researched. LEVEL OF EVIDENCE: Level III (Diagnostic Study).

Guided growth: preliminary results of a multinational study of 967 physes in 537 patients.

BACKGROUND: Guided growth by tension band plating is commonly used to correct coronal plane deformity. The purpose of this study was to measure the effect and further define parameters that influence results in coronal plane deformity around the knee. METHODS: The retrospective multicentre study included data on 967 physes in 537 patients, with an average follow-up of 16 months after plate insertion. Alignment analysis was compared preoperatively and in at least two measurements postoperatively, as well as with parameters that influence the rate and amount of correction. RESULTS: Average age at plate implantation was 11.35 years (SD 3.29).Of those with femoral deformities, 85% of the patients finished the treatment and of those, 70% were corrected to standard alignment, while 14% have not yet achieved correction, and are still growing.Of those with tibial deformities, 75% of the patients finished the treatment and of those 80% were corrected to standard alignment, while 25% have not yet achieved correction and are still growing.The calculated rate of correction was 0.77°/month for the femur and 0.79°/month for the tibia.In terms of complications, the overall rate of infection was 1.48%. In three patients (0.55%) screw breakage was recorded.Factors found to significantly influence the amount of correction were age at plate implantation and direction of deformity. CONCLUSION: Temporary hemiepiphysiodesis takes the advantage of physiological physeal growth to effectively treat angular deformities. Success of treatment is influenced by the age of the patient at plate implantation and direction of deformity. LEVEL OF EVIDENCE: IV.

Camurati-Engelmann disease: review of the clinical, radiological, and molecular data of 24 families and implications for diagnosis and treatment.

Camurati-Engelmann disease (CED) is a rare autosomal dominant type of bone dysplasia. This review is based on the unpublished and detailed clinical, radiological, and molecular findings in 14 CED families, comprising 41 patients, combined with data from 10 other previously reported CED families. For all 100 cases, molecular evidence for CED was available, as a mutation was detected in TGFB1, the gene encoding transforming growth factor (TGF) beta1. Pain in the extremities was the most common clinical symptom, present in 68% of the patients. A waddling gait (48%), easy fatigability (44%), and muscle weakness (39%) were other important features. Radiological symptoms were not fully penetrant, with 94% of the patients showing the typical long bone involvement. A large percentage of the patients also showed involvement of the skull (54%) and pelvis (63%). The review provides an overview of possible treatments, diagnostic guidelines, and considerations for prenatal testing. The detailed description of such a large set of CED patients will be of value in establishing the correct diagnosis, genetic counselling, and treatment.

A combined use of a free vascularised flap and an external fixator for reconstruction of lower extremity defects in children.

PURPOSE: To describe a combined use of a free vascularised flap and an external fixator for reconstruction of lower extremity defects in children, and correction of equinus contracture developed after removal of the external fixator using a circular dynamic frame. METHODS: Seven children (4 males) aged 4 to 12 (mean, 8) years were treated with 9 free vascularised flaps for 8 limbs (bilaterally in one patient and for a failed flap in another). Patient pathologies included: 3 soft tissue degloving injuries, one soft tissue and bone avulsion, one severe burn contracture, one resurfacing of soft tissue and bone necrosis, and one osteosarcoma resection defect. Free flap reconstruction was delayed in 6 patients (range, 3 weeks to 4 years). Static external fixators were used to stabilise the free vascularised flaps at the time of reconstruction, with the ankle in a neutral position. RESULTS: The mean follow-up was 5 (1-10) years. All flaps but one survived; the failed one was immediately reconstructed with a contralateral, latissimus dorsi flap. One anastomosis following a Kirschner-wire injury was successfully revised. Six patients had pin tract infections and were treated with oral antibiotics. Two patients developed equinus contracture 6 and 3 years later, after removal of the external fixator, and were corrected by distraction, using a dynamic Ilizarov frame. CONCLUSION: The combined use of a free flap and an external fixator for salvage of lower extremities is useful in children. Late development of equinus contracture can be safely corrected by distraction, without compromising flap viability.

Raloxifene-mediated increase in matrix metalloproteinase-1 production by activated monocytes.

Matrix metalloproteinases (MMPs), proteolytic enzymes produced by monocytes, may contribute to atherosclerotic arterial wall remodeling and to plaque rupture. Because estrogen influences the synthesis of MMPs, we examined the effect of raloxifene, a selective estrogen receptor modulator, on monocyte MMP production. Human primary blood monocytes treated with raloxifene (10 micromol/L) in the presence of lipopolysaccharide (LPS) or tumor necrosis factor-alpha and granulocyte-macrophage colony-stimulating factor induced a 2- to 3-fold increase in MMP-1 production by monocytes. The enhancement of MMP-1 production by raloxifene in LPS-activated monocytes occurred through a cyclooxygenase-2- and prostaglandin E(2)-independent mechanism. Additionally, compared with monocytes acquired during the placebo phase, peripheral blood monocytes from 5 of 6 healthy postmenopausal women treated with raloxifene (60 mg daily for 1 month) in a clinical trial produced significantly higher levels of MMP-1 when the monocytes were activated with LPS. Furthermore, serum obtained during the raloxifene phase from 4 of these subjects, when added to control monocytes, significantly enhanced LPS-induced MMP-1 production compared with that from serum obtained during the placebo phase. In summary, raloxifene increases the production of MMP-1 in activated monocytes; this effect may be favorable in atherosclerotic arterial wall remodeling but unfavorable for plaque stability.

Establishment of the hematopoietic microenvironment in the marrow of matrix-induced endochondral bone.

Implantation of demineralized diaphyseal bone matrix (DBM) into subcutaneous sites in allogeneic Long-Evans rats results in new endochondral bone formation accompanied by hematopoietic bone marrow differentiation in the newly formed ossicles. In the present study, we investigated the relationship between the time of appearance of hematopoietic stem cells (CFU-S) and those of certain postulated elements of the hematopoietic microenvironment, i.e., fibroblast colony-forming cells (CFC-F), colony-stimulating factors (CSF), and collagen types. CFU-S were first detected at 16 days' postimplantation in the developing ossicle. Their numbers increased exponentially until day 24, decreased slightly between days 27 and 33, and then slowly increased in number again until day 36. CFC-F were present at day 10, and their numbers increased exponentially until day 15, decreased dramatically until day 24, and then remained constant till day 35. Thus, the transient growth of CFC-F preceded the appearance and growth of CFU-S in the ossicle by two or three days.

Prolonged use of foot abduction brace reduces the rate of surgery in Ponseti-treated idiopathic club feet.

PURPOSE: There is conflicting evidence related to factors affecting the rates of recurrence of idiopathic club feet using the Ponseti method. We attempt to evaluate the predictors of success and failure in our physiotherapy-led Ponseti club foot clinic. METHODS: We evaluated 189 children with 279 club feet with a mean follow-up of 6.3 years for the following: Pirani score at presentation, number of casts for correction, indication for Achilles tenotomy, and the duration of foot abduction brace (FAB) use, in relation to outcome. Outcome measures were the need for additional surgery and functional scores. Based on the pattern and rate of ossification of the tarsal bones in idiopathic club foot, a much longer FAB weaning protocol was designed and practiced since 2000. The objective of this study was to answer the question of whether a prolonged period of FAB use reduces the need for surgery in Ponseti-treated idiopathic club foot. RESULTS: Thirty-six feet (12.9 %) underwent additional surgery. The Pirani score and the number of cast changes had no influence on the rate of surgery. The duration of FAB use had a significant effect on the outcome, i.e., the rate of surgery and functional scoring. Operated children used the FAB for 28 months versus 33 months in the non-operated group (p < 0.05). Only a minor delay in the attainment of walking age was noted (average 15 months). CONCLUSIONS: The duration of FAB treatment was found to be the most influential on the functional results and on rate of surgery. Close follow-up and longer FAB weaning program reduced the rates of recurrence.

Monoclonal antibodies recognize antigen expressed by osteoblasts.

A marrow stromal osteogenic cell line (MBA-15) was used to create monoclonal antibodies (MoAbs). In this study, we describe a series of MoAbs for mouse marrow stroma (MMS) (MMS-25/17, MMS-85/12, MMS-302/40, and MMS-319/4) that recognized antigens expressed by stromal cells including osteoblastic cells. The MoAbs were screened against various cell and tissue types. MMS-85/12 was positive in detecting an antigen that was highly abundant in osteoblastic cells and primary adherent bone marrow cultures (BMC) but was negative for the marrow adipocytes copartner. The MMS-85/12 MoAb is an IgGl immunoglobulin. The immunohistochemical staining pattern is suggestive of the antigen being associated with the osteoblasts' plasma membrane and with the extracellular matrix constituent secreted by these cells. Western blotting and immunoprecipitation indicated that the antigen that was recognized by MMS-85/12 apparently had a molecular weight of 84 dD.

Bone formation by marrow osteogenic cells (MBA-15) is not accompanied by osteoclastogenesis and generation of hematopoietic supportive microenvironment.

This study was aimed at elucidating the relationship between osteogenic activity of marrow stromal cells and their ability to support hematopoiesis followed by the bone-remodeling process. We used the MBA-15 cell line, which expresses osteoblastic phenotype in vitro and forms bone in diffusion chamber. We have compared bone formation and hematopoietic responses elicited in vivo by these cells with the implantation of freshly isolated bone marrow cells (BMC) or demineralized tooth matrix (DTM). Both MBA-15 cells and BMC, implanted under the kidney capsule, yielded intramembraneous bone, but DTM, implanted subcutaneously, elicited endochondral bone. MBA-15 formed primary bone, mimicking only the initial sequential stages of the ossification process. Neither histologic signs of bone resorption and remodeling nor tartrate-resistant acid phosphatase (TRAP)-positive cells and marrow formation were observed. Bone formation was monitored biochemically. Functions for hematopoietic stem and committed cell content were measured by GM-CFU and BFU-E assays that confirmed the morphologic observations. In both BMC and DTM implantation, bone formation was followed by hematopoietic activity, osteoclastogenesis, and remodeling. We conclude that MBA-15 osteoprogenitor cells, despite their extensive bone formation ability, are unable to form a microenvironment supportive for hematopoiesis and osteoclastogenesis or to initiate bone remodeling.

Gnathodiaphyseal dysplasia: a syndrome of fibro-osseous lesions of jawbones, bone fragility, and long bone bowing.

We report an unusual generalized skeletal syndrome characterized by fibro-osseous lesions of the jawbones with a prominent psammomatoid body component, bone fragility, and bowing/sclerosis of tubular bones. The case fits with the emerging profile of a distinct syndrome with similarities to previously reported cases, some with an autosomal dominant inheritance and others sporadic. We suggest that the syndrome be named gnathodiaphyseal dysplasia. The patient had been diagnosed previously with polyostotic fibrous dysplasia (PFD) elsewhere, but further clinical evaluation, histopathological study, and mutation analysis excluded this diagnosis. In addition to providing a novel observation of an as yet poorly characterized syndrome, the case illustrates the need for stringent diagnostic criteria for FD. The jaw lesions showed fibro-osseous features with the histopathological characteristics of cemento-ossifying fibroma, psammomatoid variant. This case emphasizes that the boundaries between genuine GNAS1 mutation-positive FD and other fibro-osseous lesions occurring in the jawbones should be kept sharply defined, contrary to a prevailing tendency in the literature. A detailed pathological study revealed previously unreported features of cemento-ossifying fibroma, including the participation of myofibroblasts and the occurrence of psammomatoid bodies and aberrant mineralization, within the walls of blood vessels. Transplantation of stromal cells grown from the lesion into immunocompromised mice resulted in a close mimicry of the native lesion, including the sporadic formation of psammomatoid bodies, suggesting an intrinsic abnormality of bone-forming cells.

Renal phosphate wasting in fibrous dysplasia of bone is part of a generalized renal tubular dysfunction similar to that seen in tumor-induced osteomalacia.

Fibrous dysplasia (FD) of bone is characterized by focal replacement of normal bone and marrow with abnormal bone and fibrous tissue. It arises from postzygotic activating mutations of the GNAS1 gene. Hypophosphatemia due to renal phosphate wasting has been reported in association with FD as a part of the McCune-Albright Syndrome (MAS), which is characterized by FD, skin hyperpigmentation, and precocious puberty. To date, the prevalence and mechanism of phosphate wasting has not been well studied. We evaluated 42 patients with FD/MAS. Serum and urine samples were tested for indices of mineral metabolism, amino acid handling, and markers of bone metabolism. Twenty (48%) patients had some degree of renal phosphate wasting. Nephrogenous cyclic adenosine monophosphate (cAMP) was normal in FD patients, suggesting that the underlying cause of phosphate wasting is not the presence of activating GNAS1 mutations in the kidney. In addition, there was evidence of a more generalized renal tubulopathy as represented by the presence of abnormal vitamin D metabolism, proteinuria in 36 (86%) patients, and aminoaciduria in 39 (94%) patients. Renal phosphate wasting significantly correlated with the degree of bone involvement, as assessed by serum and urine markers of bone metabolism, suggesting that a circulating factor produced by FD bone and impacting on the kidney may be the mechanism. These data show that phosphaturia as part of a generalized renal tubulopathy represents the most common extraskeletal manifestation of FD and that the observed tubulopathy is similar to that seen in tumor-induced osteomalacia (TIO).