Presence and magnitude of anterior physeal separation in slipped upper femoral epiphysis helps identifying those at high risk for avascular necrosis.

AIMS: We sought to determine if the magnitude of anterior physeal separation (APS) in slipped upper femoral epiphysis was a predictor for the subsequent development of avascular necrosis (AVN). Anterior Physeal Separation (APS) is defined as the distance between the anterior lip of the bony capital epiphysis and the lateral corresponding point of the adjacent bony metaphysis on the Lauenstein radiographic view. It represents hinging of the posterior aspect of the metaphysis with the anterior epiphysis lifting away from its adjacent metaphysis, indicating instability and potential vulnerability of the vessels. PATIENTS AND METHODS: A retrospective review of all patients treated regionally for slipped upper femoral epiphysis over a 9 year period (2010-2018 inclusive) were identified. Data regarding demographics, radiological parameters and outcomes was recorded. APS was measured on a Launestein radiograph view, with the patient supine, the hip and knee are flexed to 40°, and the hip externally rotated 45°, with film-focus distance of 100 cm. Analysis of the APS was performed to validate a threshold above which AVN occurs. RESULTS: We identified 147 hips in 142 patients, of which 5 had bilateral slips at the time of presentation. Average anterior physeal separation was 3.8 ± 1.8 mm, with higher grade slips having significantly greater APS values. Increased APS values were seen with Loder "unstable" slips. Seven hips (4.8%) developed AVN, and in these cases the APS was significantly larger than those who did not (8.5 ± 1.4 Vs 3.9 ± 1.7; p < 0.001). Receiver operator curve analysis demonstrated a critical value of 7.5 mm was associated with a 100% sensitivity and 98.6% specificity for AVN. We identified some grade II/moderate slips with high APS values had similar outcomes to grade III/severe slips, and therefore suggest that APS may serve to alert the surgeon on counselling patients on the risk of developing AVN and to consider strategies to minimise the risk of AVN. CONCLUSIONS: APS is sensitive, specific, accurate and reliable for the association with AVN in SUFE. Its values closely reflect the high AVN rates seen in acute and unstable SUFE. This risk is greatest if the magnitude of APS exceeds the critical value of 7.5 mm.

Temporal changes in slipped upper femoral epiphysis at a regional level: a declining incidence and literature review.

PURPOSE: Slipped upper femoral epiphysis (SUFE) is one of the most common adolescent hip pathologies in children with potential for life-long morbidity secondary to avascular necrosis (AVN). The primary aim is to determine an up-to-date demographic of SUFE, as well as current trends in presentation and radiological characteristics. Secondary aims are to quantify prophylactic fixation and subsequent contralateral SUFE. METHODS: Between 01 January 2013 and 31 December 2015, all cases of SUFE were identified in Northern Ireland. Patient demographics, slip characteristics and outcomes are presented and the incidence rates were calculated using census data. Temporal changes in incidence, compared with a previous cohort, are demonstrated. RESULTS: A total of 56 patients (80 hips) were identified. Based on census data, SUFE incidence has declined from 7.14 to 4.69/100,000 population aged < 16 years. Male cases predominated by > 2:1 ratio, and tended to be older than female cases. Approximately 75% of patients were above the 75th centile for age-sex adjusted body weight. Knee pain as a presenting symptom led to a delay in diagnosis. Prophylactic fixation was performed in 25.9%, with contralateral slips occurring in 27.5%. AVN occurred in 7.4% and remained static. CONCLUSION: The incidence of SUFE has declined ~34% in our region. When SUFE occurs, knee pain often results in a delay in definitive diagnosis, and commands clinical vigilance to avoid delays in diagnosis. Patients in our region should be aware of a 1-in-4 contralateral slip rate. Overall, AVN rates remain static and are acceptable, despite the declining incidence of SUFE. LEVEL OF EVIDENCE: Level III - Retrospective Cohort Study.

Delayed diagnosis of developmental dysplasia of the hip in Northern Ireland: can we do better?

Developmental dysplasia of the hip (DDH) should be diagnosed as early as possible to optimise treatment. The current United Kingdom recommendations for the selective screening of DDH include a clinical examination at birth and at six weeks. In Northern Ireland babies continue to have an assessment by a health visitor at four months of age. As we continue to see late presentations of DDH, beyond one year of age, we hypothesised that a proportion had missed an opportunity for earlier diagnosis. We expect those who presented to our service with Tonnis grade III or IV hips and decreased abduction would have had clinical signs at their earlier assessments. We performed a retrospective review of all patients born in Northern Ireland between 2008 and 2010 who were diagnosed with DDH after their first birthday. There were 75 856 live births during the study period of whom 645 children were treated for DDH (8.5 per 1000). The minimum follow-up of our cohort from birth, to detect late presentation, was four years and six months. Of these, 32 children (33 hips) were diagnosed after their first birthday (0.42 per 1000). With optimum application of our selective screening programme 21 (65.6%) of these children had the potential for an earlier diagnosis, which would have reduced the incidence of late diagnosis to 0.14 per 1000. As we saw a peak in diagnosis between three and five months our findings support the continuation of the four month health visitor check. Our study adds further information to the debate regarding selective versus universal screening.

Pelvic kinematics and their relationship to gait type in hemiplegic cerebral palsy.

While there is general clinical consensus that children with Unilateral Spastic Cerebral Palsy (USCP) walk with an increased anterior pelvic tilt and the affected hemipelvis retracted, there is less agreement to observations in the coronal plane. Furthermore, the relationship of 3D pelvic kinematic parameters to the Winters, Gage and Hicks (WGH) hemiplegic gait classification has not been reported in the literature. Valid 3-D kinematic gait data were obtained in a representative population of 91 children with hemiplegia (56 M, mean age 10.8 yrs, age range 5-18 yrs; WGH classification Type I n=32, II n=5, III n=7, IV n=9, unclassified n=38). Deviations of symmetry and range of movement from our normative data set (n=48; 26F; mean age 9.9 yrs; age range 5-18 yrs) for mean tilt, tilt range, and difference between affected and unaffected sides for obliquity and rotation were defined as normal, mild, moderate or severe (<1 standard deviation (SD); >1<2 SD; >2<3 SD; >3 SD, respectively). Increased pelvic tilt range (>1 SD) was observed in 60.4% and pelvic retraction (>1 SD) was observed in 61.5% of USCP children in this study. Weak but significant correlations were found between WGH gait type and pelvic obliquity (ρ=0.29; p<0.01). No other correlations were found. Factors such as leg length discrepancy modify the functional leg length throughout the gait cycle contributing to the deviations observed. The evaluation of gait abnormalities in USCP should not be limited to the use of classifications based on sagittal plane kinematics but should seek to include 3D kinematics of the pelvis.

Further evidence of validity of the Gait Deviation Index.

In this paper, the relationship of the Gait Deviation Index (GDI) to gross motor function and its ability to distinguish between different Gross Motor Function Classification System (GMFCS) levels was determined. A representative sample of 184 ambulant children with CP in GMFCS levels I (n=57), II (n=91), III (n=22) and IV (n=14) were recruited as part of a population-based study. Representative gait cycles were selected following a 3D gait analysis and gross motor function was assessed using the Gross Motor Function Measure (GMFM). GDI scores were calculated in Matlab. Valid 3D kinematic data were obtained for 173 participants and both kinematic and GMFM data were obtained for 150 participants. A substantial relationship between mean GDI and GMFM-66 scores was demonstrated (r=0.70; p<0.001) with significant differences in mean GDI scores between GMFCS levels (p<0.001) indicating increasing levels of gait deviation in subjects less functionally able. The relationship between the GDI, GMFM and GMFCS in a representative sample of ambulators, lends further weight to the validity of the GDI scoring system. Furthermore it suggests that the subtleties of gait may not be wholly accounted for by gross motor function evaluation alone. Gait specific tools such as the GDI more likely capture both the functional and aesthetic components of walking.

The effects of industry standard averaging and filtering techniques in kinematic gait analysis.

INTRODUCTION: Conventional methods for determining normative gait patterns consist of filtering marker trajectories prior to processing with subsequent averaging of individual normalized data. This may result in temporal shifts of key parameters and potentially distort normative datasets. Nevertheless, this is the standard method employed by state of the art motion analysis systems. This study compared two different methods of averaging filtered and unfiltered kinematic data. METHODS: Forty-eight non-impaired children (22M, 26F, mean age 9.85 years, range 4.2-17 years) underwent three-dimensional gait analysis using a Vicon system (Vicon, Oxford, UK). Gait data were processed with and without the Woltring filtering routine, commonly used to minimize marker trajectory noise. Filtered data were imported into Matlab (MathWorks, Natick, MA) where a representative gait cycle (RGC) for each leg of all participants was selected. Mean and standard deviation values for left and right limbs (n=96) for filtered and unfiltered data were calculated for seven different parameters within the RGC, without respect to timing. Similar values were obtained using the standard method. The values from the different averaging methods with and without filtering were compared. RESULTS: Differences of up to 2.2 degrees were found between averaging methods and up to 3.31 degrees between filtered and unfiltered data. DISCUSSION: Both the Woltring filtering routine and the standard averaging method cause signal dampening. While a Matlab-based tool may afford greater scope when analysing kinematic gait data, the standard averaging method still returns representative values when utilising data from able-bodied subjects.

Arthrodiastasis in Perthes' disease. Preliminary results.

We have examined the effect of arthrodiastasis on the preservation of the femoral head in older children with Perthes' disease. We carried out a prospective trial in boys over the age of eight years and girls over seven years at the time of the onset of symptoms. The patients had minimal epiphyseal collapse and were compared with a conventionally treated, consecutive, historical control group. Arthrodiastasis was applied for approximately four months. The primary outcome measure was the extent of epiphyseal collapse at the end of the fragmentation phase. One of the 15 treated hips and nine of the 30 control hips showed a loss of height of 50% or more of the lateral epiphyseal column on the anteroposterior radiographs (Herring grade-C classification). On a Lauenstein view, one of the treated hips and 19 of the control hips showed at least a loss of height of 50% of the anterior epiphyseal column. The complications of arthrodiastasis included pin-site infection in most hips, transient joint stiffness in two, and breakage of a pin in two. The final outcome will be known when all the patients and the control group reach skeletal maturity.

Primary care anticoagulant management using near patient testing.

BACKGROUND: Indications for anticoagulant treatment are increasing and new approaches to anticoagulant services require a shift from hospital to primary care. AIM: To pragmatically test the validity and effectiveness of primary care anticoagulant management using near patient testing. METHODS: Twelve CoaguCheck monitors were supplied to 16 rural practices that had previously provided supervision of anticoagulant therapy. Practices were required to record data for eligible patients from September 1998 to April 1999 and to forward one blood sample per week to the regional hospital laboratory for parallel testing. RESULTS: Nine practices returned data on 122 patients. Indications for anticoagulation Included atrial fibrillation (n = 56), valve replacement (n = 12) and deep venous thrombosis or pulmonary embolus (n=12). Regression of the mean of 185 paired readings against their difference confirmed the validity of the CoaguCheck monitor (r2 = 0.00 [95% CI -0.38 to 0.38]). There were 692 International Normalised Ratio (INR) tests performed representing an average of 5.7 tests per patient. The desired therapeutic range was provided for 609 (88%) of these tests; 294 (48.3%) were within the desired therapeutic range. Results differed significantly between practices. CONCLUSIONS: This study confirmed the validity of anticoagulant management using the CoaguCheck monitor in primary care.

Anterior physeal separation. A sign indicating a high risk for avascular necrosis after slipped capital femoral epiphysis.

A study of 78 children (110 hips) was undertaken in an attempt to assess the risk of avascular necrosis (AVN) after slipped capital femoral epiphysis based on the radiological appearances of the hip at the time of presentation. Physeal separation, which was defined as the amount of separation of the anterior lip of the epiphysis from the metaphysis on the frog lateral view, was assessed. Of the eight hips which developed AVN, seven had anterior physeal separation. We conclude that anterior physeal separation is associated with a high incidence of subsequent AVN after slipped capital femoral epiphysis and that screw fixation may not be appropriate in these patients.

Botulinum toxin treatment of spasticity in diplegic cerebral palsy: a randomized, double-blind, placebo-controlled, dose-ranging study.

This study evaluated the efficacy and safety of three doses of botulinum toxin A (BTX-A; Dysport) in 125 patients (mean age 5.2 years, SD 2; 54% male)with dynamic equinus spasticity during walking. Participants were randomized to receive Dysport (10, 20, or 30 units/kg) or placebo to the gastrocnemius muscle of both legs. Muscle length was calculated from electrogoniometric measurements and the change in the dynamic component of gastrocnemius shortening at four weeks was prospectively identified as the primary outcome measure. All treatment groups showed statistically significant decreases in dynamic component compared with placebo at 4 weeks. Mean improvement in dynamic component was most pronounced in the 20 units/kg group, being equivalent to an increase in dorsiflexion with the knee extended at 19 degrees, and was still present at 16 weeks. The safety profile of the toxin appears satisfactory.

Clinical screening for developmental dysplasia of the hip in Northern Ireland.

PROBLEM: The incidence of late diagnosed developmental dysplasia of the hip requiring surgery in Northern Ireland is high. The reported incidence was 1.14 per 1000 children born during 1983-7. DESIGN: Comparative retrospective study. BACKGROUND AND SETTING: Clinical screening programme in Northern Ireland. Key measure for improvement: Reduced rate of operative intervention in children with developmental dysplasia of the hip detected after 6 months of age. STRATEGIES FOR CHANGE: Increased emphasis on staff training, introduction of a centralised nurse led clinic to improve access to orthopaedic surgeons, and increased use of ultrasonography. EFFECTS OF CHANGE: The incidence of developmental dysplasia of the hip diagnosed after 6 months in children born between January 1991 and December 1997 fell to 0.59 per 1000, presumably due to improved early detection. Nevertheless, 29 (16%) of the affected hips were not diagnosed when the child was first referred in the first 3 months of life. In addition, for 27 affected hips in children diagnosed after the age of 6 months there was a known risk factor (family history or breech delivery). LESSONS LEARNT: Improvements to screening processes can reduce late incidence of developmental dysplasia of the hip. Further steps to improve detection in children with known risk factors and rate of detection at first referral could reduce late presentation further.

Effect of a rigid ankle-foot orthosis on hamstring length in children with hemiplegia.

Eighteen children with hemiplegia, mean age 8 years 5 months, underwent gait analysis and musculoskeletal modelling using specially designed software. The maximum lengths of the hamstrings were determined for each child walking in and out of an ankle-foot orthosis (AFO). The muscles were deemed to be short if shorter than the normal average -1SD. In bare feet 8 participants had short medial hamstrings with a higher proportion of these in the less involved individuals. All participants showed an increase in maximum hamstring length when wearing an AFO. In all but one child this was sufficient to restore hamstring length to within normal limits. These finding suggest that hamstring pathology in hemiplegic gait is usually secondary to more distal lower limb pathology.

Opinion statement on the minimal acceptable standards of healthcare in cerebral palsy.

PURPOSE: Recent studies have shown a marked variation in the standards of healthcare for young people with disabilities in different regions of the UK and even within the same health district. Equity in the provision of healthcare is a fundamental principle of the NHS. However, this can only be measured against an agreed minimal standard of healthcare that serves as a benchmark for healthcare purchasers and providers. The aim of the present document is to develop a set of minimum standards of healthcare for children and adults with cerebral palsy (CP). METHODS: The document was developed in two stages by a multi-professional and multi-disciplinary group of practitioners in the field of CP. Initially, members of the panel jointly formulated a statement of what they believed should be the minimal acceptable standards of healthcare in CP drawing on their own experience and the published scientific evidence. In the second stage the views of some of the relevant professional bodies and voluntary organizations on the draft statement were sought. The responses of these organizations were incorporated into the final document if agreed by the panel. RESULTS AND CONCLUSIONS: Twenty-two recommendations were made. These were considered the minimum standards of care in a district general hospital. The emphasis was on the organisation and delivery of healthcare for children with CP. The statement is intended to stimulate debate especially in relation to the equity of service provision throughout the country and may be used to inform purchasers of healthcare. Similarly, it may also be useful to providers of healthcare as an audit tool.

Relevance of the popliteal angle to hamstring length in cerebral palsy crouch gait.

The popliteal angle is a widely used clinical means of assessing hamstring length in cerebral palsy patients. The relevance of the popliteal angle as a measure of hamstring length was assessed in this prospective study. Sixteen patients with cerebral palsy with crouch gait had their conventional and modified popliteal angles measured by nine observers on two separate occasions. With use of the conventional and modified forms of the test, 74 and 70%, respectively, of the observed variability was inter-and intraobserver related. The range of SDs for each observer using the conventional test was 7.1-13.6 degrees (average 10.9 degrees ), and with use of the modified form of the test, the range was 6.3-4.2 degrees (average 10.5 degrees ). The maximum hamstring length of each subject during gait was determined by three-dimensional modelling of their lower limbs. The modified popliteal angle measurements of the most repeatable observer demonstrated an inverse relationship between modified popliteal angle and maximum hamstring length (p < 0.01) and muscle excursion (p < 0.01). Only 10 of 32 limbs had short medial hamstrings.

Safety profile and efficacy of botulinum toxin A (Dysport) in children with muscle spasticity.

Botulinum toxin A (BTX-A) is widely used in the management of muscle spasticity in children. However, at present the dose of BTX-A for a given patient is selected empirically. The aim of this study is to provide dosage guidelines that are based on risk/benefit assessment. This was a multicentre retrospective study of the safety profile and efficacy of BTX-A in children with chronic muscle spasticity. Data in 758 patients who received a total of 1594 treatments were analysed (mean age 7.2 years; 429 males, 329 females). Spastic cerebral palsy (CP) was the most common diagnosis (94% of the study sample). Of all treatments 7% resulted in adverse events; incidence was related to the total dose rather than the dose calculated on the basis of body weight. The highest incidence of adverse events was observed in patients who received >1000 IU of BTX-A per treatment session. The odds of an adverse event was 5.1 times greater for this group of patients than for those who had 250 IU or less (p<0.001). A good overall response to treatment was reported in 82% and treatment goals were fully or partially achieved in 3% and 94% of participants respectively. More patients in the highest dose group reported functional deterioration. Interestingly, multilevel treatments resulted in a better response than single-level treatments (odds ratio 1.7, 95% CI 1.3 to 2.2,p=0.001).

The role of coagulation abnormalities in the development of Perthes' disease.

Recent reports have suggested an association between Perthes' disease and an underlying thrombophilic or hypofibrinolytic tendency. In Northern Ireland there is a high incidence of Perthes' disease (11.7 per 100,000 or 1 in 607 children) in a stable paediatric population. We reviewed 139 children with Perthes' disease and compared them with a control group of 220 aged- and gender-matched healthy primary schoolchildren with similar racial and ethnic backgrounds. There were no significant deficiencies of antithrombotic factors protein C, protein S, antithrombin III or resistance to activated protein C. A total of 53 (38.1%) of the children with Perthes' disease had a prolonged activated partial thromboplastin time (>38) compared with 13 (5.9%) of the control group (p < 0.001). Our findings have shown that using standard assays, thrombophilia secondary to antithrombotic factor deficiency or resistance to activated protein does not appear to be an aetiological factor for Perthes' disease. The cause of the prolonged activated partial thromboplastin time, usually associated with a clotting factor deficiency, is under further investigation.

The influence of ankle-foot orthoses on gait and energy expenditure in spina bifida.

We examined the effect of ankle-foot orthoses (AFOs) on gait and energy expenditure in children with spina bifida. Nine boys and three girls, 6 to 16 years of age, took part in the study. There were four children each with L4, L5, and sacral level lesions. Each child underwent gait analysis and energy consumption studies with and without AFOs. Walking speed was faster with AFOs (mean, 58 m/min) than without (mean, 50 m/min, p < 0.01). Stride length improved significantly (p < 0.001) from 0.89 m barefoot to 1.08 m with AFOs. Double support time was decreased from 0.32 seconds barefoot to 0.28 seconds with AFOs (p < 0.05). The oxygen cost of walking was significantly better with (0.33 mL/kg/m) than without AFOs (0.41 mL/kg/m, p < 0.001). Hip flexion at initial contact was increased. Ankle kinematics were unchanged, but ankle power generation showed a significant improvement; from 0.5 W/kg barefoot to 1.3 W/kg with AFOs. Increased ankle power generation results in improved hip flexion and stride length, which contributes to increased walking speed and reduced oxygen cost. The stability conferred by the AFOs is reflected in the reduced time spent in double support.

Deprivation, urbanisation and Perthes' disease in Northern Ireland.

It has been suggested that Perthes' disease is more prevalent in urban areas, and that the risk increases with deprivation. We present the findings of a preliminary analysis of Perthes' disease in Northern Ireland, which is shown to have one of the highest national annual rates of incidence in the world (11.6 per 100000). Of the 313 children diagnosed over a seven-year period, 311 were allocated to the enumeration districts of the 1991 census, thus allowing the incidence to be calculated using both spatial and non-spatial aggregation. The cases were grouped according to the size of the settlement from highly urbanised to open countryside and by level of area deprivation. While the incidence of Perthes' disease was found to be associated with indicators of the level of deprivation for areas, there was no evidence to suggest that there was an increased risk in urban areas; the highest rate was found in the most deprived rural category.

Botulinum toxin A in hamstring spasticity.

Hamstring injection of Botulinum toxin A (BtA) may have a role in the conservative management of flexed knee gait in cerebral palsy or in simulating the effect of surgery. Ten children who were likely to require future hamstring lengthening were injected. Short term outcome was assessed by clinical examination and 3-D gait analysis. Mean popliteal angle decreased by 16 degrees and maximum knee extension in stance increased by 8 degrees, the latter relapsing by 12 weeks. Mean pelvic tilt tended to increase suggesting that isolated hamstring weakening be approached with caution. Energy cost of walking was not significantly changed in six of the ten patients. A small increase in knee extension in stance was often associated with patient satisfaction. There are theoretical grounds for expecting an associated increased longitudinal muscle growth after BtA injection.

The effect of botulinum toxin A on gastrocnemius length: magnitude and duration of response.

Thirty-nine ambulant children (22 with hemiplegia, 17 with diplegia) with spastic cerebral palsy receiving isolated gastrocnemius muscle injection with botulinum toxin A were studied prospectively. The children had a mean age of 6 years (range 3 to 13 years). Measurement of gastrocnemius muscle length was used to estimate the dynamic component of each child's spasticity and to quantify the response. There was a strong correlation between the dynamic component of spasticity before injection and the corresponding magnitude of the response after injection. Children undergoing repeated injections showed similar correlations. A strong correlation was found between the duration of response and the dynamic component. Children with hemiplegia showed twice the duration for a given dynamic component compared with those with diplegia when injected with the same total dose per unit body weight. Long-term lengthening did not occur for the cohort, although some patients showed a response at a 12-month follow-up. By delaying shortening, the injections may have a role in delaying the need for surgery. Injections were well tolerated with few side effects.