Aims

Despite the presence of screening programmes, infants continue to present with late developmental dysplasia of the hip (DDH), the impact of which is significant. The aim of this study was to assess infants with late presenting dislocation of the hip despite universal clinical neonatal and selective ultrasound screening.

Over a 15-year prospective period, 201 infants with a clinically unstable hip at neonatal screening were subsequently reviewed in a ‘one stop’ clinic where they were assessed clinically and sonographically. Their mean age was 1.62 weeks (95% confidence interval (CI) 1.35 to 1.89). Clinical neonatal hip screening revealed a sensitivity of 62% (mean, 62.6 95%CI 50.9 to 74.3), specificity of 99.8% (mean, 99.8, 95% CI 99.7 to 99.8) and positive predictive value (PPV) of 24% (mean, 26.2, 95% CI 19.3 to 33.0). Static and dynamic sonography for Graf type IV dysplastic hips had a 15-year sensitivity of 77% (mean, 75.8 95% CI 66.9 to 84.6), specificity of 99.8% (mean, 99.8, 95% CI 99.8 to 99.8) and a PPV of 49% (mean, 55.1, 95% CI 41.6 to 68.5). There were 36 infants with an irreducible dislocation of the hip (0.57 per 1000 live births), including six that failed to resolve with neonatal splintage.

Most clinically unstable hips referred to a specialist clinic are female and stabilise spontaneously. Most irreducible dislocations are not identified from this neonatal instability group. There may be a small subgroup of females with instability of the hip which may be at risk of progression to irreducibility despite early treatment in a Pavlik harness.

A controlled study is required to assess the value of neonatal clinical screening programmes.

Cite this article: Bone Joint J 2015;97-B:265-9.

Summary Statement. Differential expression of canonical and noncanonical Wnt signalling along cartilage canals and osteochondral junctions is dependent on age. Increased gene expression of PTHrP along cartilage canals and Ihh along osteochondral junctions suggests paracrine feedback in articular-epiphyseal cartilage. Introduction. Wnt signaling has been shown to regulate chondrocyte differentiation during pre-/post-natal cartilage development. In addition, parathyroid-related peptide(PTHrP) and Indian hedgehog(Ihh) create a negative feedback loop in growth cartilage, but less is known in articular cartilage. The objective of this study was to elucidate expression of regulatory molecules in chondrocytes surrounding cartilage canals and osteochondral junctions during neonatal and pre-adolescent development. We hypothesised there would be increased expression of canonical Wnt signalling molecules and Ihh in osteochondral junction chondrocytes compared to cartilage canal chondrocytes. In addition, we hypothesised that Wnt signaling and PTHrP expression would be greater in neonates than pre-adolescents. Patients & Methods. Osteochondral samples were obtained(IACUC-approved) from normal femoropatellar joints of 14 euthanised immature horses(6 neonates, 8 pre-adolescents). Samples were frozen in OCT for laser capture microdissection(LCM) or fixed in 4% paraformaldehyde and paraffin-embedded for immunohistochemistry. Chondrocytes surrounding cartilage canals and osteochondral junctions were captured using LCM. Following RNA isolation, equine-specific β-catenin, Wnt-4, Wnt-5b, Wnt-11, Dickkopf-1(Dkk-1), low-density lipoprotein receptor-related protein-4,-6(Lrp4, Lrp6), Axin1, Wnt inhibitory factor-1(WIF)-1, secreted Frizzled-related protein-1,-3,-5(sFRP), retinoic acid receptor gamma(RARG), RAR-inducible serine carboxypeptidase(SC-PEP), Ihh, PTHrP, VEGF, PDGF, MMP-13, and 18S mRNA expression levels were evaluated by two-step real-time qPCR. Following immunohistochemistry using rabbit polyclonal or mouse monoclonal primary antibodies (confirmed by Western blot), spatial tissue protein expression was scored (0–3). Statistical analysis included Wilcoxon signed rank test(paired samples) or rank sum test(unpaired samples)(P<0.05). Results. Gene expression in chondrocytes along cartilage canals was significantly higher for PTHrP, β-catenin, Lrp6, Axin1, sFRP5, RARgamma, and SC-PEP than osteochondral junctions. Conversely, gene expression of Ihh, Wnt4, Wnt11, sFRP3, and VEGF were higher in osteochondral junction chondrocytes than cartilage canals. There was higher protein expression of β-catenin, PDGF, VEGF, and MMP-13 along osteochondral junctions than cartilage canals of pre-adolescents. Neonates had higher gene expression of PTHrP, Wnt-5b, sFRP3, Lrp6, and RARG in cartilage canal chondrocytes than pre-adolescents, while Ihh, Wnt-11, Lrp4, and Dkk1 were significantly higher in pre-adolescents. Immunostaining was higher for β-catenin and Wnt-11 in pre-adolescent osteochondral junction cartilage than neonates. No differences were found between age groups for Wnt-4 immunostaining. Dkk1 protein expression was significantly higher in the middle cartilage layer of pre-adolescents than neonates. Immunostaining was greater for Ihh and PTHrP in the deep cartilage layer of pre-adolescents than neonates. PDGF, VEGF, and MMP13 protein expression was higher in the superficial cartilage layer of pre-adolescents than neonates. Discussion. Wnt/β-catenin and Ihh/PTHrP signaling regulate cartilage differentiation during development and are important in endochondral ossification. This study revealed cell-specific, age-related differences in gene/protein expression of both regulatory pathways. Cells surrounding cartilage canals typically appeared small/rounded compared to larger chondrocytes along osteochondral junctions, likely due to different developmental stages. Higher PTHrP gene expression along cartilage canals and Ihh expression along osteochondral junctions may reflect these stages, suggesting paracrine feedback in articular-epiphyseal cartilage. β-catenin signaling may induce chondrocyte hypertrophy, potentially by enhancing Ihh and MMP-13 expression. Differential expression of canonical(β-catenin, Wnt-4, Lrp4, Lrp6) and noncanonical Wnt signalling(Wnt-5b, Wnt-11) and Wnt inhibitors (Dkk1, Axin1, sFRP3, sFRP5, Wif-1) surrounding cartilage canals and osteochondral junctions provides evidence of age-related interactions during postnatal development

An eight-week-old boy developed severe thoracic spondylodiscitis following pneumonia and septicaemia. A delay in diagnosis resulted in complete destruction of the T4 and T5 vertebral bodies and adjacent discs, with a paraspinal abscess extending into the mediastinum and epidural space. Antibiotic treatment controlled the infection and the abscess was aspirated. At the age of six months, he underwent posterior spinal fusion in situ to stabilise the spine and prevent progressive kyphosis. At the age of 13 months, repeat imaging showed lack of anterior vertebral body re-growth and he underwent anterior spinal fusion from T3 to T6 and augmentation of the posterior fusion. At the age of five years, he had no symptoms and radiographs showed bony fusion across the affected levels.

Spondylodiscitis should be included in the differential diagnosis of infants who present with severe illness and atypical symptoms. Delayed diagnosis can result in major spinal complications with a potentially fatal outcome.

Introduction. Neonatal fractures are often quite distressing to parents and medical teams involved. Their management can be daunting due to the small size of the patient, the concern of the new parents and the fear of the obstetric staff about litigation and deformity or long term disability of the neonate. Aim. This study assesses the radiological and functional outcome of neonatal fractures up to two years post injury. Methods. We reviewed the notes of neonates at our hospital who sustained fractures spanning a 4 year period. Clavicle and humeral fractures were treated in a swaddling bandage for 3 weeks. Femoral fractures were treated in a gallows traction for 2–3 weeks. Xrays were taken once weekly. Patients were examined two years following their injury and function of the affected limb was assessed and compared with the unaffected side. Radiographs of the previously fractured bones were also taken at the 2 years follow up. Results. Eighteen (18) neonates sustained fractures predominantly due to birth trauma. There were four clavicle fractures, one fracture of a humerus, three femoral and 10 skull fractures. All seven (7) patients extremity fractures healed satisfactorily clinically and radiologically, with no residual deformity, limb length discrepancy or functional impairment at 2 years follow up. All parents were very satisfied with the outcome. Discussion and Conclusion. Neonatal fractures occur in <1% of births. Causes include birth trauma and congenital bone disease. Neonates with fractures are referred for Orthopaedic management which can be intimidating due to the infrequency of management of this cohort of patients. In our study all of our neonates with long bone fractures had good radiological results and no functional deficit when reviewed after 2 year. Clinicians can be reassured that neonatal fractures have a propensity to heal rapidly without residual functional or radiological abnormality as long as alignment is grossly maintained initially

Clinical prediction algorithms are used to differentiate transient synovitis from septic arthritis. These algorithms typically include the erythrocyte sedimentation rate (ESR), although in clinical practice measurement of the C-reactive protein (CRP) has largely replaced the ESR. We evaluated the use of CRP in a predictive algorithm.

The records of 311 children with an effusion of the hip, which was confirmed on ultrasound, were reviewed (mean age 5.3 years (0.2 to 15.1)). Of these, 269 resolved without intervention and without long-term sequelae and were considered to have had transient synovitis. The remaining 42 underwent arthrotomy because of suspicion of septic arthritis. Infection was confirmed in 29 (18 had micro-organisms isolated and 11 had a high synovial fluid white cell count). In the remaining 13 no evidence of infection was found and they were also considered to have had transient synovitis. In total 29 hips were categorised as septic arthritis and 282 as transient synovitis. The temperature, weight-bearing status, peripheral white blood cell count and CRP was reviewed in each patient.

A CRP > 20 mg/l was the strongest independent risk factor for septic arthritis (odds ratio 81.9, p < 0.001). A multivariable prediction model revealed that only two determinants (weight-bearing status and CRP > 20 mg/l) were independent in differentiating septic arthritis from transient synovitis. Individuals with neither predictor had a < 1% probability of septic arthritis, but those with both had a 74% probability of septic arthritis. A two-variable algorithm can therefore quantify the risk of septic arthritis, and is an excellent negative predictor.

Since September 1964, neonates born in New Plymouth have undergone clinical examination for instability of the hip in a structured clinical screening programme. Of the 41 563 babies born during this period, 1639 were diagnosed as having unstable hips and 663 (1.6%) with persisting instability were splinted, five of which failed. Also, three unsplinted hips progressed to congenital dislocation, and there were four late-presenting (walking) cases, giving an overall failure rate of 0.29 per 1000 live births, with an incidence of late-walking congenital dislocation of the hip of 0.1 per 1000 live births.

This study confirms that clinical screening for neonatal instability of the hip by experienced orthopaedic examiners significantly reduces the incidence of late-presenting (walking) congenital dislocation of the hip.

We reviewed 600 children with 640 sites of acute haematogenous osteomyelitis treated between 1983 and 2002. Neonates and patients with septicaemia were excluded. The mean age of the children was 7 years (3 months to 13 years). The male to female ratio was 2.3:1. The diagnosis was made clinically and with the help of special investigations. The while cell count was elevated in 75% and the ESR in 98%. Blood cultures were positive in 79%. Radiographs showed metaphyseal rarefaction and/or periosteal reaction in 19% and isotope scan was positive in 43%. No aspiration was done to establish the diagnosis. In nine sites (1.5% of operated sites) the diagnosis was regarded as incorrect (no growth or subsequent bony changes on radiographs). The distal femur was the most common site (25%), followed by the distal tibia (20%), proximal tibia (19%), proximal femur (7%), proximal humerus (5%), forearm (5%), distal fibula (4%), pelvis (4%), calcaneum (3%) and other (8%). Staphylococcus aureus was cultured in 89% of sites. Treatment was with intravenous cloxacillin, followed by oral flucloxacillin for 6 weeks. Surgery was performed at 94.5% of sites. The 5.5% sites that were not operated upon were in the pelvis or were early limb sites with no swelling. At surgery, 21% of sites were found to have intra-osseous pus. In the remaining 79%, there was subperiosteal pus at 41% of sites and extraperiosteal pus at 38%. Patients were followed up until adequate bone stock was present on radiographs and no sinus or sequestrum was present. Poor results (sequestrum and/ or pathological fracture) occurred in 8.3% (53 sites). Poor results were not site-specific, but 99% occurred in patients with subperiosteal or extraperiosteal pus

We reviewed 821 children with 869 sites of septic arthritis treated from 1983 to 2002. Neonates and patients with septicaemia and penetrating injuries were excluded. There were two age groups: 46% of the children were two years or younger (mean 1.1 years) and 54% were between 3 and 12 years (mean 6.8 years). The male to female ratio was 1.7:1. The diagnosis was made clinically and with the help of special investigations. The white cell count was elevated in 67% and the ESR in 96%. Blood culture was positive in 28%. Radiographs demonstrated widening of joint spaces in 19% and isotope bone scan was positive in 11% of sites, mainly in the hip. No diagnostic joint aspiration was done. In 42 sites (4.6%) the diagnosis was regarded as incorrect because there was no growth or white cells. The most common site of septic arthritis was the knee (37%), followed by the hip (30%), ankle (14%), elbow (10%), shoulder (5%), wrist (3%) and subtalar joint (1%). Treatment was with open arthrotomy and antibiotics (cloxacillin and/or ampicillin). Bacteriologically the most common finding was no growth (50% in each age group). In the younger group the most common finding was Haemophilus influenzae (24.5%). Staphylococcus aureus was found in 37% of the older group. From 2000 the incidence of H. influenzae declined, probably owing to the introduction of vaccine in 1998. Results at 30 sites (3.5%) were poor. There was avascular necrosis in 18 hips, chondrolysis in five hips and three ankles, and stiffness in two knees, an ankle and a subtalar joint. Further analysis showed that poor results were more likely to occur in older patients with S. aureus and where there was a delay in treatment. Where good results were achieved, the mean delay was 3.5 days. It was 9.3 days where results were poor

Of the 34 723 infants born between 1 June 1992 and 31 May 2002, the hips of 2578 with clinical instability or at-risk factors for developmental dysplasia of the hip were imaged by ultrasound.

Instability of the hip was present in 77 patients, of whom only 24 (31.2%) had an associated risk factor. From the ‘at-risk’ groups, the overall risk of type-III dysplasia, instability and irreducibility was 1:15 when family history, 1:27 when breech delivery and 1:33 when foot deformity were considered as risk factors. Of those hips which were ultrasonographically stable, 88 had type-III dysplasia.

A national programme of selective ultrasound screening of at-risk factors for the diagnosis of hip dislocation or instability alone cannot be recommended because of its low predictive value (1:88). However, the incidence of type-III dysplasia and hip dislocation or dislocatability in the groups with clinical instability, family history, breech position and possibly postural foot deformity as risk factors could justify a programme of selective ultrasound imaging.