Session 10: Pediatrics
17. November
09:30 - 11:00
Lokale: Vingsal 3
Chair: Marie Fridberg and Julie L. Erichsen
71. Stryde - the Danish Experience
Jan Duedal Rölfing ¹, Søren Kold ², Tobias Nygaard ³, Mindaugas Mikuzis ², Michael Brix 4 , Christian Faergemann 4, Martin Gottliebsen ¹, Michael Davidsen ¹, Juozas Petruskevicius ¹, Ulrik Kähler Olesen ³
¹ Orthopaedic Reconstruction and Children’s Orthopaedics, Aarhus University
Hospital
² Department of Orthopaedics, Interdisciplinary Orthopaedics, Aalborg University
Hospital
³ Department of Orthopaedics, Limb Lengthening and Bone Reconstruction Unit,
Rigshospitalet
4 Department of Orthopaedics, Odense University Hospital
Background: Observing serious adverse
events during treatment with the Precice Stryde
bone lengthening nail (NuVasive, San Diego,
CA, USA), we conducted a nationwide cross-
sectional study.
Aim: To report the prevalence of adverse events from
all 30 lengthened bone segments of the 27
patients treated in Denmark.
Materials and Methods: Radiographs of all bone segments
were evaluated regarding radiographic changes
in February 2021. We determined the number of
bone segments with late onset of pain and/or
radiographically confirmed osteolysis, periosteal
reaction, or cortical hypertrophy in the junctional
area of the nail.
Results: In 30 bone segments of 27 patients we
observed radiographic changes in 21/30
segments of 20/27 patients, i.e., 19/30
osteolysis, 12/30 periosteal reaction (most often
multi-layered), and 12/30 cortical hypertrophy
in the area of the junction between the
telescoping nail parts. Late onset of pain was a
prominent feature in 8 patients. This is likely to
be a prodrome to the bony changes.
Discoloration (potential corrosion) at the nail
interface was observed in multiple removed
nails. 15/30 nails were still at risk of developing
complications, i.e., were not yet removed.
Interpretation / Conclusion: All Stryde nails should be monitored
at regular intervals until removal. Onset of pain
at late stages of limb lengthening, i.e.,
consolidation of the regenerate,
should warrant immediate radiographic
examination regarding osteolysis, periosteal
reaction, and cortical hypertrophy, which may be
associated with discoloration (potential
corrosion) of the nail. We recommend removal
of Stryde implants as early as possible after
consolidation of the regenerate.
72. A novel plate concept for rotational guided growth of the femur – An experimental porcine pilot study
Ahmed Abood ¹, Ahmed Halloum ¹, Søren Kold ¹, Marie Arildsen ¹, Ole Rahbek ¹, Jan Duedal Rölfing ²
¹ Department of Orthopaedics, Aalborg University Hospital
² Department of Orthopaedics, Aarhus University Hospital
Background: The use of guided growth to correct
rotational lower limb deformities in children
has been increasingly investigated.
Alternative use of eight-plates and cable
connected cannulated screws suggest the
possibility of applying guided growth to
correct rotational deformities. Still, there is
no commercially available device for this
purpose. We have developed a novel plate
concept for rotational guided growth, which
has proven effective in a cadaverous model,
however large animal studies are lacking.
Aim: To proof the concept of the novel plate by
rotating porcine femora through guided
growth.
Materials and Methods: Six female porcines (n = 6) with a mean
weight of 43 kg (38 - 47) were included in a
paired design. The 3D printed titanium
plates were inserted at baseline on the
medial and lateral aspect of the left distal
femoral physis. Each plate was attached
using two 4.5 mm titanium screws. The
animals were housed for 12 weeks before
undergoing MRI, radiographs, and
euthanasia. Change in femoral version and
length between the right femur and left
femur was determined on MRI. Clinical
torsion was assessed using standardized
photographs with the animal placed supine
on a levelled table.
Results: The surgery was well tolerated by all
animals, and they were ambulatory on the
first post-operative day. A torsional
difference was created in all operated
femora. Mean change in femoral version
was 12.5 degrees (9 - 16). Mean length of
the operated femur was 2.9 mm (0 - 7)
shorter than the non-operated. Mean clinical
change in rotation was 10.3 degrees (7 -
14).
Interpretation / Conclusion: The plates were able to rotate all operated
femora as intended. However, a decrease in
axial growth due to the rotational guided
growth cannot be ruled out. We did not
assess possible changes in joint
morphology. More comprehensive large
animal studies investigating the precision of
rotational potential of the plates in addition
to detailed growth analyses including
alignment in the coronal and sagittal plane
are planned.
73. Midwives can measure the pubo-femoral distance reliably in ultrasound screening for developmental dysplasia of the pediatric hip.
Hans-Christen Husum, Michel Bach Hellfritszch, Mads Henriksen, Natallia Lapitskaya, Bjarne Møller-Madsen, Rikke Damkjær Maimburg, Ole Rahbek
Interdisciplinary Orthopaedics, Aalborg University Hospital; Department of Radiology, Aarhus University Hospital; Department of Children's Orthopaedics, Aarhus University Hospital; Danish Paediatric Orthopaedic Research; Department of Gynaecology and Obstetrics, Aarhus University Hospital
Background: Ultrasound screening for developmental dysplasia of the hip (DDH) is conventionally based on the Graf ultrasound technique which necessitates an experienced ultrasound user to be interpreted correctly.
The pubo-femoral distance (PFD) has been proposed as a highly sensitive ultrasound screening tool for DDH, with low variability.
Aim: The aim of this study was to examine if midwives undergoing minimal training, could reliably perform pediatric hip ultrasound and measure PFD and to evaluate the learning curve of the midwives.
Materials and Methods: We recruited eight midwives with no prior experience in hip ultrasound for training in PFD measurements. They participated in a two-hour theoretical seminar on DDH screening and the PFD measurement. All midwives performed two rounds of independent blinded measurements on 15 static ultrasound images seven days apart and participated in four supervised live scanning sessions over two weeks. The midwives were compared to a group of three experienced musculoskeletal radiologists. Reliability and agreement were evaluated using interrater correlation coefficients (ICC) and Bland Altman plots. Linear regression was used to quantify the learning curve of the midwives as a group with absolute difference between midwife and radiologist as a function of number of scans.
Results: There was near complete intra- and interrater agreement (ICC > 0.89) on static ultrasound images across both rounds of rating and across both groups of raters.
The midwives scanned a mean of 29 hips (range 24-35). Mean difference between midwife and supervising radiologists was 0.36mm 95% CI (0.12-0.61) for the first session which decreased to 0.2mm 95% CI (0.04-0.37) in the final session.
ICC for PFD measurements between radiologist and midwives increased from 0.59 95% CI (0.37;0.75) to 0.78 95% CI (0.66;0.86) across sessions.
The mean absolute difference between midwife and radiologist PFD measurements decreased by 0.1mm (95% CI 0.02-0.17) for every ten scans the midwives gained in experience (p=0.008).
Interpretation / Conclusion: Midwives reliably perform PFD measurements of pediatric hips, with minimal training, and with clinically insignificant differences compared to experienced musculoskeletal radiologists.
74. Preparing an automatic pin site infection detection tool with machine learning for home-based surveillance
Marie Fridberg ¹ , Sowmya Annadatha ², Qirui Hin ², Tobias Jensen ², Jianan Liu ², Søren Kold ², Søren Rahbek ², Ming Shen ²
1. Interdisciplinary Orthopaedics, Aalborg University Hospital, Denmark
2. Department of Electronic Systems, Aalborg University,Denmark
Background: To detect early signs of pin site infection infrared
thermography has been suggested to provide
quantitative information of clinical signs of pin
site infection.
Aim: Our vision is to invent a pin site infection
thermographic surveillance tool for patients at
home. A preliminary step to this goal, is to
automate the process of locating the pin and
detecting the pin sites in thermographic images
efficiently, exactly, and reliably for extracting the
pin site temperatures.
Materials and Methods: Images (digital conventional and thermographic)
were obtained in a controlled clinical setting and
in an uncontrolled home setting. The total
number of images of pin-sites used for
developing the machine learning algorithm
(images of pin sites) before augmentation was
n=1708. The images was augmented, in to
totally n=10.409. Randomly divided into a
training set (n=8325), a validation set (n=1040)
and a test set (n=1044) of images. The Pin
Detection Model (PDM) was developed as
follows: A You Only Look Once (YOLOv5) based
object detection model with a Complete
Detection Intersection over Union (CDIoU) was
pre-trained by the hospital dataset and fine
tuned by the home dataset through transfer
learning. The performance was compared with
other conventional models (FCOS and YOLOv4)
for deep and transition learning to improve
performance and precision. Maximum
Temperature Extraction (MTE) Based on Region
of Interest (ROI) for all pin sites was generated
Results: An automatic tool that can identify and annotate
pin sites on digital images using bounding
boxes was established. An obstacle was
shifting, solved by calibration and image
registration with a transformation matrix that
converted every pixel on the digital images to a
coordinate system of the thermographic image.
The PDM algorithm was built on YOLOv5 with
CDIoU and has a precision of 0.976 and it offers
the pin site detection in 1.8 milliseconds. The
PDM algorithm enabled MTE at an automatically
detected ROI on the skin surface.
Interpretation / Conclusion: These results enable automatic pin site
annotation on thermography with a precision of
0.976 in 1.8 milliseconds. This work, paves the
way for future research on infection assessment
using thermography.
75. Reliability of thermography in a clinical setting to detect skin temperatures at pin sites. A test-retest study
Marie Fridberg¹, Malene Engesgaard Christensen², Mathias Sørensen², Bente Madsen², Ole Rahbek¹ , Søren Kold¹
Interdisciplinary Orthopaedics, Aalborg University Hospital, Denmark; Department
of Health Science and Technology, Aalborg University, Denmark.
Background: Thermography has been suggested to objectify
clinical signs of pin site infection by measuring
skin surface temperatures.
Aim: The aim was to test the reliability of
thermography by investigating reproducibility in
a test retest setup and the intra- and inter-rater
reliability using two different temperature
extraction methods (TEM).
Materials and Methods: Thermography was obtained of 216 pin sites in
a test-retest setup using a FLIR T540 infrared
camera. Session A (n=216) and B (n=216) were
conducted in a standardized realistic clinical
setting with 30 min. in between. The test-retest
setup was similar according to photographer,
patient, position, acclimatization, pins and
environmental conditions. Minor variations in
angle (random) and distance (40-60cm) to the
pin site reflected the realistic random variations
introduced by the photographer. All images
(n=432) were analyzed using two different TEM
in FLIR tools software: The 3-point method and
the MaxROI method. Intra-rater reliability: 20
pins were analyzed twice by the same rater with
one week in between. Inter-rater: 20 pins were
analyzed by 3 raters blinded. ICC was
calculated using a two-way mixed effects model
with absolute agreement and 95% confidence
intervals.
Results: Test -retest reliability of the 216 pin sites: 3-point
(ICC=0.9, CI 0.88-0.93) and MaxROI method
(ICC=0.91CI 0.88-0.93). The intra-rater
reliability test of the two different TEM of 20 pin
sites: 3-point (ICC=0.65 CI 0.30-0.84) and
MaxROI method (ICC=0.91CI 0.78-0.96). The
inter-rater reliability test performed by using
three different raters extracting temperatures of
20 pin sites: 3-point (ICC=0.86 CI 0.76-0.92)
and MaxROI method (ICC=1,00 (0.996) CI 0.99-
0.99).
Interpretation / Conclusion: Thermographic imaging used to measure skin
temperatures at pin sites using a FLIR T540
infrared camera was found reproducible in a
realistic clinical setting. We found an excellent
test-retest reliability for both TEM despite minor
variations in distance and angle. The MaxROI
had the best intra-and inter-rater reliability.
76. Pubo femoral distances in hip ultrasound do not vary between lateral and supine examination positions in newborns.
Hans-Christen Husum, Christian Klitt Jensen, Mads Henriksen, Michel Bach Hellfritszch, Bjarne Møller-Madsen, Ole Rahbek
Interdisciplinary Orthopaedics, Aalborg University Hospital; Department of Radiology, Aarhus University Hospital; Department of Children's Orthopaedics, Aarhus University Hospital; Danish Paediatric Orthopaedic Research
Background: Ultrasound screening for developmental dysplasia of the hip (DDH) is conventionally based upon the method developed by Graf. In 2013 the pubo-femoral distance (PFD) was proposed as a new ultrasound screening measurement, defined as the minimally measurable distance between the medial aspect of the femoral head and the pubic bone with a PFD above 6.0 mm considered pathological. No consensus exists on the positioning of the child when performing the PFD examination.
Aim: Our aim was to examine the agreement of the PFD when measured with the child in the lateral versus supine position.
Materials and Methods: We included a consecutive series of children referred for hip ultrasound suspect of DDH during a period of two months.
The PFD measurement was obtained for each child for both hips in the lateral position, afterwards the child was placed in the supine position and the PFD measurement was repeated on both sides.
Ultrasound examinations were performed by two experienced pediatric musculoskeletal radiologists
Mean PFD values for lateral and supine positioning were compared using Student’s paired t-test and agreement was analyzed using Bland Altman plot.
Results: We included 30 children (15 boys), mean age at examination was 34 days (range 13-83). Mean PFD in lateral position was 3.5 mm 95%CI (3.2; 3.7) and mean PFD in supine position was 3.6 95%CI (3.4 ; 3.9). Mean difference in PFD between examination positions was 0.16 mm 95% CI(-0.01 ;0.31) p=0.04. Inspection of the Bland Altman plot did not reveal a systematic difference in PFD between examination positions with increasing average PFD value.
Interpretation / Conclusion: Shifting from lateral to supine examination positions during hip ultrasound had no clinically significant impact on PFD measurements. These findings underline the versatility of the PFD measurement as a screening tool for DDH.
77. Complications of Orthopedic Treatment in Patients Diagnosed with X-linked Hypophosphatemic Rickets.
Søren Kold, Carl Paludan, Kristoffer Thomsen, Ole Rahbek
Department of Orthopaedics, Aalborg University Hospital
Background: X-linked Hypophosphatemic Rickets (XLHR) in
children with a Rickets Severity Score = 2 can
now be treated with the new fibroblast growth
factor 23 (FGF23) antibody drug which prevents
bone deformities and increases gait endurance.
This study illustrates the extend and
complications in the traditional orthopedic
treatment in XLHR patients. The impact of
surgery and severity of complications in this
patient population has not been systematically
assessed before. These data are needed to
justify the very expensive antibody treatment
Aim: This study reviews systematically the
complications of orthopedic treatment in XLHR
patients
Materials and Methods: The search strategy resulted in 215 studies in
which data were collected from 19 eligible
studies and complications were categorized.
Results: XLHR patients without FGF23 antibody
treatment undergo multiple surgeries. 168
complications were reported in 172 patient. One
complication occurred in average per surgical
procedure for XLHR in the published literature.
The 168 reported complications were
categorized as follows: Type 1 (n=79):
Complications with minimal intervention required
and treatment goal still achieved, Type II (n=41):
Complications with substantial change in
treatment plan and treatment goal still achieved,
Type IIIA (n=23): Complications with failure to
achieve treatment goal and no new pathology or
permanent sequelae, Type IIIB (n=25):
Complications with failure to achieve treatment
goal and/or new pathology or permanent
sequelae
Interpretation / Conclusion: In average one complication occurred per
surgery and the severity of complications was
remarkable. The treatment goal was not
achieved in 28 % of surgeries whereof half of
these resulted in permanent sequalae or new
pathology. Complications were possibly
underreported in current literature and
complications of surgery in XLHR may therefore
be underestimated. Our findings support the use
of FGF23 antibody for treatment of the skeletal
changes in XLHR instead of surgery as the
reported side effects of antibody treatment is
negligible compared to the impact of surgeries
and related complications
78. The incidence of physeal fractures in the lower limb and the frequency of premature physeal closure, limb length discrepancy, and angular deformity: A cohort study of 236 physeal fractures.
David Alexander Lukas Wang Cant, Christian Færgemann
Section for Pediatric Orthopaedics, Department for Orthopaedic Surgery and
Traumatology, Odense University Hospital.
Background: Pediatric fractures is a common injury among
children and adolescents. Physeal fractures
constitute a particular concern because of the risk of
accompanying growth disturbances.
Aim: The aim of this study was to estimate incidence
rates (IR) of physeal fractures in the lower limb and
the frequency of premature physeal closure (PPC)
leading to limb length discrepancy (LLD) and
angular deformity (AD).
Materials and Methods: This retrospective cohort evaluated 236 children
between 2013-2020 treated for a physeal fracture in
either tibia, distal femur, or distal fibula. All medical
records and radiographs/CT-scans were reviewed to
obtain information regarding type of physeal fracture
and the development of growth disturbances.
Furthermore, we investigated relevant predictive risk
factors.
Results: The total incidence rate of physeal fractures was
36.4 (CI:30.3-39.3) per 100.000 person-years,
with 1.2 (CI:0.50-23.1) of distal femur, 5.7
(CI:3.1-7.8) of proximal tibia, 14.1 (CI:11.4-17.2)
of distal tibia, and 13.6 (CI:11.0-16.7) of distal
fibula. The overall frequency of growth
disturbance was 9.7%. Within distal femur,
proximal tibia, distal tibia, and distal fibula the
frequency of growth disturbance was 37.5%,
15.4%, 13.5%, and 1.1%, respectively. The
highest frequency of growth disturbances was in
Salter-Harris type II and IV fractures (60.9 % and
34.9%). We found a significant higher risk of
developing growth disturbances if the patient
was treated operatively (p<0.001), sustained the
fracture from a high-energy injury (p=0.02), or if
the initial displacement was = 3 mm (p=0.01).
Interpretation / Conclusion: Despite a relatively low incidence of physeal
fractures, we found that a recognizable part
eventually develops growth disturbance, particularly
children presenting with certain risk factors. We
accentuate the importance of consistent and uniform
growth evaluations after sustaining a physeal
fracture.
79. Surgical procedures in infants with early diagnoses of developmental dysplasia of the hip. A prospective 4-year follow-up study.
Ingebrigt Grimstad Holstad , Christian Færgemann
Section for Pediatric Orthopaedics, Department of Orthopaedics and Traumatology,
Odense University Hospital, Odense, Denmark
Background: To detect unstable dysplastic hips early,
neonatology specialists routinely screen all new-
borns in Denmark. Infants with detectable risk
factors or clinical signs of dysplasia are referred
to a combined pediatric orthopaedic and
radiologic examination. A previous study has
shown that 17% of all infants referred for this
combined examination meet the diagnostic
criteria of dysplasia. Four per cent have unstable
hips that need treatment. Dysplastic hips may
normalize spontaneously without any
intervention due to the natural growth. However,
some infants need one or more surgical
intervention to achieve stable and non-dysplastic
hips.
Aim: To determine the proportion of infants with early
dysplasia of the hips undergoing surgical procedures
and to determine the type and number of surgical
procedures.
Materials and Methods: A prospective and consecutive study of all infants
aged 0-6 months diagnosed with dysplasia of the
hips in the combined pediatric orthopaedic and
radiologic examination in the Region of Southern
Denmark 2013-2017. From medical records, we
obtained information about all surgical procedures in
the hips including open or closed reductions,
arthrographies, tenotomies, and pelvic osteotomies
before the age of 4 years.
Results: Overall, 281 infants with hip dysplasia were
included. The median age at first examination was
48 days. In 254 (90%) of the infants, the hips
resolved spontaneously, and 27 (10%) needed one
or more surgical interventions. Overall, the 27
infants had 47 surgical interventions as 12 infants
had more than one intervention. One infants had five
surgical interventions. The most frequent surgical
procedures were closed reduction and arthrography
with or without adductor tenotomy (58 %) and pelvic
osteotomy (27%). Among infants with surgical
interventions, 23 (8.2%) had unstable hips, and four
(1.4 %) had stable hips. All four infants with stable
hips had an arthrography and none required a pelvic
osteotomy.
Interpretation / Conclusion: This study supports the propensity for spontaneous
normalization of early dysplasia of the hips in
infants. Only a small proportion of the infants
needed surgical interventions to achieve stable and
non-dysplastic hips.
80. The proportion of hip dysplasia in infants referred for combined pediatric orthopedic and radiologic examination in Region of Southern Denmark 2013-2019
Simon Norlén , Christian Færgemann
Section for Pediatric Orthopaedics, Department of Orthopaedics and Traumatology,
Odense University Hospital.
Background: To detect developmental hip dysplasia (DDH)
early, all newborns in Denmark are examined
postnatally by a pediatrician and by a primary
care physician at 5 weeks and 5 months of age.
Suspect findings are referred to a combined
pediatric orthopedic examination and
ultrasonography. This combined examination is
resource demanding, and studies have found
variating effects of the screening. Previous
studies have described variating proportions of
DDH among infants referred for the combined
examination. Furthermore, only few studies have
examined which causes most commonly lead to
referral and the association between different
causes of referral and DDH.
Aim: To determine the proportions of infants with DDH
and hip dislocation in infants referred for a combined
pediatric orthopedic and radiologic assessment, and
to describe the association between DDH and
different reasons of referral.
Materials and Methods: A prospective study of all infants aged 0-6 months
referred for a combined pediatric orthopedic and
radiologic examination of the hips at Odense
University Hospital or Kolding Hospital 2013-2019.
We calculated the overall proportion of DDH and hip
dislocations and the proportions stratified by
different reasons of referral. We considered an
acetabular index > 30° on radiographs or Graf Type
2b or worse on ultrasonographies diagnostic of
DDH.
Results: Of the 1,989 infants included, 334 (17%) were
diagnosed with DDH and 94 (4.7%) had hip
dislocations. The proportions of infants with DDH
among infants with a single reason of referral were
36% for breech position, 25% for familial disposition,
14% for hip click, 8% for asymmetry, and 3% for
twins. The proportions of infants with unstable hip(s)
were 14% for familial disposition, 12% for breech
position, 3% for hip click, 3% for twins, and 1% for
asymmetry.
Interpretation / Conclusion: The study demonstrates that a considerable
proportion of infants referred for the combined
examination have DDH and that some reasons of
referral are clinically more important. The study
showed that in infants with hip click and asymmetry,
a considerable proportion had DDH. We recommend
that infants with hip click or asymmetry should be
referred for a the pediatric orthopedic and radiologic
examination.