Imaging of Disease and Normal Variant Patterns in Pediatric Hips

The pediatric hip undergoes significant changes from infancy through adolescence. Proper maturation is crucial for the development of a stable and functional hip joint. Imaging interpretation of the pediatric hip requires distinguishing normal variants and maturation patterns from pathology. We review femoral ossification centers, variants, and conditions that affect the proximal femur, such as Legg-Calvé-Perthes disease; the acetabulum, such as developmental hip dysplasia; the acetabular labrum, such as femoroacetabular impingement; and synovial pathology in children through adolescence. Understanding the spectrum of hip conditions and using advanced imaging techniques are essential for the accurate diagnosis and effective management of pediatric hip disorders.

[Possibilities of orthopedic technical care for extremity lengthening and reconstruction]

BACKGROUND

Orthopedic technical care plays a crucial role in improving function and mobility for patients undergoing limb lengthening and reconstruction. The treatment strategy is based on a precise classification of the defect, taking into account factors such as joint instability, muscle pathology and limb length discrepancy.

CHOICE OF AIDS

The selection of orthopedic aids depends on the specific deformity, its classification and the individual needs of the patient. Through interdisciplinary decision-making and customized adaptations of prostheses and orthoses, optimal function and aesthetically pleasing outcomes can be achieved. The utilization of custom-made technical components, such as traction devices combined with elastic liners, is essential for long-term treatment success and can support surgical interventions. The treating physician's expertise is crucial in selecting the appropriate orthopedic technical device following limb lengthening and reconstruction.

Feasibility of Computer-Aided Design in Limb Lengthening Surgery: Surgical Simulation and Guide Plates

Objective

To evaluate the feasibility and utility of computer‐aided design (CAD) in surgical treatment of leg length discrepancy (LLD) using monorail external fixators.

Methods

In the present case series, we retrospectively analyzed seven patients diagnosed with LLD who were surgically treated using a monorail external fixator between June 2018 and August 2020. A personalized surgical emulation of each patient was designed using CAD based on preoperative CT scans to measure limb parameters. Through reverse engineering, a surgical guide plate was then designed to assist with correcting the limb deformity. Patient general information and clinical history, leg length, mechanical lateral distal femoral angle (mLDFA), anatomical anterior distal tibial angle (aADTA), and surgical parameters were recorded during the perioperative period. Three months after external fixator removal, distraction‐consolidation time (DCT), healing index (HI), and lower extremity function score (LEFS) were calculated, and statistically analyzed by paired T‐test.

Results

The mean limb lengthening achieved was 6.41 ± 2.54 (range, 3.30–10.54) cm with either varus or valgus correction. The mean operative duration was 151 ± 41.87 (84–217) minutes and mean blood loss was 53.58 ± 22.51(25–87) ml. The mean distraction‐consolidation time was 3.67 ± 1.13 (range, 2.5–6.0) months and mean external fixator duration was 11 ± 2.45 (range, 8–14) months. The mean healing index (HI) was 18.11 ± 3.58 (range, 12.8–22.7) days/cm. Mean LEFS scores improved postoperatively from 32.17 ± 8.57 (range, 24–45) to 61.17 ± 6.68 (range, 50–67) with a significant difference (T = –14.26,P < 0.001).

Conclusions

Simultaneous length and angular correction can be achieved by incorporating CAD into the surgical treatment of patients with LLD, without compromising postoperative lower limb function. CAD demonstrates utility in the surgical treatment of LLD by improving the functionality of monorail external fixators.

Congenital musculoskeletal anomalies - key radiographic findings

Although radiographs are generally performed in the neonatal period to evaluate for causes of respiratory distress or to evaluate line placement, close attention to the osseous structures can provide important clues to an underlying diagnosis. Although segmentation anomalies can be random, they are frequently associated with more complex entities such as VACTERL association. A butterfly vertebral body can hint at a possible diagnosis of Alagille syndrome even before jaundice develops in an infant with a murmur. Close evaluation of the sacrum can identify abnormalities that point to caudal regression or Currarino triad. Other classic musculoskeletal abnormalities in the extremities are readily apparent on physical exam but require radiographic evaluation to define anatomy. Diagnoses such as congenital pseudoarthrosis of the clavicle, Apert syndrome, constriction band syndrome, and proximal focal femoral deficiency have pathognomonic imaging findings. Given that treatment for these is usually delayed until later in life, extremity imaging might not occur in the neonatal period.

Musculoskeletal imaging in neonates: use of ultrasound

High-resolution US is a practical, cost-effective modality to evaluate the musculoskeletal system in neonates. US can be performed portably in the neonatal intensive care unit so that the critically ill infant can be evaluated with minimal distress. Sonography is noninvasive and does not require sedation; typical questions that might require the use of MRI or CT in older children can be rapidly resolved with US. Dynamic imaging can be used in real time to stress joints and see how articular structures relate. Given the advantages of US within the neonatal population, it has been widely used to evaluate for neonatal fractures, congenital joint abnormalities, limb deficiencies as well as muscular and soft-tissue abnormalities.

Pediatric Hip Disorders: Imaging Guidelines and Recommendations

Hip disorders are a wide range of conditions commonly affecting patients in the pediatric age group. Reaching an accurate diagnosis of these conditions in children may be challenging. The optimal use of image modalities in the approach of a child with possible hip pathology is essential, which allows radiologists and clinicians to narrow the differential diagnosis and reach a definitive diagnosis, which can consequently result in early and appropriate interventions leading to improved outcomes. Therefore, this article aims to provide practicing radiologists and clinicians with up-to-date and evidence-based imaging spectrum guidelines and recommendations for common pediatric hip disorders.

Overview and Spinal Implications of Leg Length Discrepancy: Narrative Review

Leg length discrepancy (LLD) is an underrecognized and prevalent condition among the U.S. population, with effects varying depending on the cause and size of the discrepancy. LLD occurs when the paired lower extremities are unequal in length and can be etiologically classified as functional or structural. Length differences are typically less than 10 mm and asymptomatic or easily compensated for by the patient through self-lengthening or shortening of the lower extremities. Literature review of the etiology, diagnostic modalities, clinical complications, and treatment option for patients with LLD. LLD can be assessed directly through tape measurements or indirectly through palpation of bony landmarks. Imaging modalities, specifically radiography, are more precise and help identify coexistent deformity. Once LLD has been diagnosed, evaluation for potential adverse complications is necessary. Discrepancies greater than 20 mm can alter biomechanics and loading patterns with resultant functional limitations and musculoskeletal disorders, such as functional scoliosis. Functional scoliosis is nonprogressive and involves a structurally normal spine with an apparent lateral curvature, which regresses fully or partially when the LLD is corrected. Long-standing LLD and functional scoliosis often result in permanent degenerative changes in the facet joints and intervertebral discs of the spine. Further understanding of the contribution of LLD in the development of scoliosis and degenerative spine disease will allow for more effective preventative treatment strategies and hasten return to function.

Embryology of the lower limb demonstrates that congenital absent fibula is a radiologic misnomer

The congenitally shortened limb (CSL) with fibular deficiency or absence has historically been graded by plain radiography, while associated cartilaginous and arterial soft tissue anomalies have been comparatively neglected. Consistent pathological evidence of remnant cartilaginous bodies in place of the fibula presupposes earlier existence of a preformed cartilaginous template of the fibula. In complete fibular radiographic absences, often associated with midline metatarsal deficiencies, the two usual nutrient arteries to the fibula fail to form, as they normally would have, around the (16-18 mm stage) sixth embryonic week. The histopathology of fallow persisting fibular anlagen, in association with missing arteries and retained primitive arteries, suggests the anlage is a dystrophic, but otherwise normally prefigured, cartilaginous scaffold of the fibula. Thus, the widely employed term absent fibula, which has been grounded in plain radiography, is a misnomer. Additionally, since the metatarsals missing in congenitally shortened limb are midline, the related term, fibular hemimelia, is similarly inaccurate. A new taxonomy, based on embryological principles rather than radiographic appearance alone, will promote limb dystrophism as a more accurate term combining arrested embryonic vascular development and congenitally shortened limb of the lower extremity.

Usual Presentation Has Odds: Unilateral Tibial Hemimelia in One of Dizygotic Twins

Tibial hemimelia is a relatively rare congenital tibial longitudinal deficiency (approximately 1 per 1 million live births), unilateral or bilateral, with a relatively intact fibula. Hemimelia results from a disruption of the lower limb developmental field during embryogenesis due to slow or even abort of chondrification process, which results in leg length discrepancy. Affected leg commonly appears short and deformed with knee, ankle, and foot involvement. It may present with a variety of associated anomalies. Surgical treatment varies according to the type and degree of deformity, and reconstructive interventions are still limited. Reported cases of tibial hemimelia are very infrequent, especially tibial hemimelia in twins. Usually, the cases were in single embryo or less frequently in one of the monozygotic twins, but no reported cases regarding tibial hemimelia in one of the dizygotic twins as this article reports.

Ultrasound Evaluation of Pediatric Orthopaedic Patients

Ultrasonography is a valuable tool that can be used in many capacities to evaluate and treat pediatric orthopaedic patient. It has the capability to depict bone, cartilaginous and soft-tissue structures, and provide dynamic information. This technique can be readily applied to a wide range of pediatric conditions, including developmental dysplasia of the hip, congenital limb deficiencies, fracture management, joint effusions, and many other musculoskeletal pathologies. There are many benefits of implementing ultrasonography as a regular tool. It is readily accessible at most centers, and information can be quickly obtained in a minimally invasive way, which limits the need for radiation exposure. Ultrasonography is a safe and reliable tool that pediatric orthopaedic surgeons can incorporate into the diagnosis and management of a broad spectrum of pathology.

Missing Midline Metatarsals Conform to Plantar Arterial Arch Dysgenesis

Midline metatarsal ray deficiencies, which occur in approximately half of congenital short limbs with fibular deficiency, provide the most distal and compelling manifestation of a fluid spectrum of human lower-extremity congenital long bone reductions; this spectrum syndromically affects the long bone triad of the proximal femur, fibula, and midline metatarsals. The bony deficiencies correspond to sites of rapid embryonic arterial transitioning. Long bones first begin to ossify because of vascular invasions of their respective mesenchymal/cartilage anlagen, proceeding in a proximal-to-distal sequence along the forming embryonic limb. A single-axis artery forms initially in the embryonic lower limb by means of vasculogenesis. Additional arteries evolve in overlapping transitional waves, in proximity to the various anlagen, during the sixth and seventh weeks after fertilization. An adult pattern of vessels presents by the eighth week. Arterial alterations, in the form of retained primitive embryonic vessels and/or reduced absent adult vessels, have been observed clinically at the aforementioned locations where skeletal reductions occur. Persistence of primitive vessels in association with the triad of long bone reductions allows a heuristic estimation of the time, place, and nature of such coupled vascular and bony dysgeneses. Arterial dysgenesis is postulated to have occurred when the developing arterial and skeletal structures were concurrently vulnerable to teratogenic insults because of embryonic arterial instability, a risk factor during arterial transition. It is herein hypothesized that flawed arterial transitions subject the prefigured long bone cartilage models of the rapidly growing limb to the risk of teratogenesis at one or more of the then most rapidly growing sites. Midline metatarsal deficiency forms the keystone of this developmental concept of an error of limb development, which occurs as a consequence of failed completion of the medial portion of the plantar arch. Therefore, the historical nomenclature of congenital long bone deficiencies will benefit from modification from a current reliance on empirical physical taxonomies to a developmental foundation.

Congenital fibular dystrophisms conform to embryonic arterial dysgenesis

The congenital short limb (CSL) with fibular deficiency has traditionally been graded by plain radiography. The most popular orthopedic classification sorts the fibular dysmorphologies into three radiographic groupings: IA (thinned), IB (proximally truncated), or II (absent). In contrast, the soft tissues have been relatively neglected. Since bone formation of the fibula progresses from the anlage, a scaffolding cartilage mold intermediate, cartilage transformation to bone is dependent upon timely embryonic arterial invasion. Absences of the requisite arteries predicate specific skeletal dysmorphologies. The usual arterial supply of the fibula is comprised primarily of the anterior tibialis artery (ATA), which uniquely supplies the proximal portion of the fibula, and also joins the peroneal artery (PA) in supplying the mid to distal fibular shaft. Combinations of the two nutrient arteries allow four potential variations of fibular vascular supply, among which the ATA and PA conjoin to supply the normal fibula and variably supply the three dysmorphic fibular models. The IA and IB deformities conform, respectively, to the absences of the PA and the ATA. Combined ATA and PA absences present in the radiographically "absent" fibula. Thus, each of the four fibular (dys)morphologies conforms to a specific embryonic pattern of arterial development. The term "dystrophism" most accurately characterizes such malformed long bones.

Proximal femoral focal deficiency - a rare congenital entity: two case reports and a review of the literature

BACKGROUND

Proximal femoral focal deficiency is an extremely rare congenital anomaly with an incidence of 1.1-2.0 in 100,000 live births. It is a dysplastic phenomenon with predilections for the proximal two-thirds of the femur leading to limb length discrepancies. We report two cases of proximal femoral focal deficiency, which is a rare entity.

CASE PRESENTATIONS

Case 1 A 4.5-month-old baby Annang tribe girl was referred in April 2019 to our Radiology Department, University of Uyo Teaching Hospital, Nigeria for lower limb radiographs. This was on account of her shortened left lower limb from birth despite uneventful antenatal history. An examination revealed bulky left thigh with abduction of her left hip joint. Radiographic evaluations showed absent left femoral capital epiphysis, with deficient proximal left femur. A diagnosis of proximal femoral focal deficiency was made. Sadly, the parents and baby failed to honor future orthopedic consultations on intimation of sequential management protocols. Case 2 A 4-month-old baby Ibibio tribe girl was similarly referred in August 2019 to the same Radiology Department for lower limb conventional radiographs due to short left lower limb that was noticed from birth. An examination showed shortened left lower limb in external rotation. Her right and left lower limbs measured 27 cm and 23 cm, respectively, with landmark taken from anterior superior iliac spine to tip of medial malleolus. A diagnosis of proximal femoral focal deficiency was made. Corroborating radiographs showed shortened and hypoplastic left femoral shaft but preserved femoral capital epiphysis. Coincidentally, the parents have not brought back their baby to our orthopedic clinic.

CONCLUSIONS

The discovery of two cases of proximal femoral focal deficiency, a rare entity, from referrals for conventional radiography in our Radiology Department encourages literature documentation. Such recognition will facilitate early institution of management, thus ensuring meaningful childhood growth.

Unilateral Isolated Proximal Femoral Focal Deficiency in an Egyptian Infant and Review of Literature

Proximal femoral focal deficiency (PFFD) is a rare congenital anomaly of the femur ranging from mild shortening to total agenesis. If left untreated, it could lead to impaired child growth, abnormal gait, vertebral abnormalities, cosmetic problems, and behavioral changes. We report on an Egyptian female, presenting to us at the age of 15 days with a short left lower limb. Both upper limbs and the right lower limb were normal and she was not dysmorphic. The skeletal survey showed an isolated short left femur. At the age of 11 months, clinical reexamination confirmed left femur shortening. Echocardiogram and abdominal sonography revealed no abnormality. Magnetic resonance imaging (MRI) of the pelvis and lower limbs revealed isolated left proximal femoral focal deficiency. Her developmental milestones were normal. She was referred to pediatric orthopaedics for early intervention and proper management. To our knowledge and after reviewing the literature, this patient represents the first case of unilateral isolated proximal focal femoral deficiency in Egypt. In conclusion, PFFD diagnosis needs a systemic skeletal–facial–genital phenotyping to differentiate from overlapping genetic disorders. Early diagnosis and radioimaging are highly important for proper management.

Bilateral fibular hemimelia associated with hip dislocation and femoral head necrosis

We describe a case of association of congenital bone abnormalities. It will allow clinicians to look systematically for other skeletal malformations and teach them how to evaluate these cases for the first time. This early screening will enable appropriate treatment to avoid complications and to preserve functional prognosis.

Postaxial limb hypoplasia (PALH): the classification, clinical features, and related developmental biology

Postaxial limb hypoplasia (PALH) is a group of nonhereditary diseases with congenital lower limb deficiency affecting the fibular ray, including fibular hemimelia, proximal femoral focal deficiency, and tarsal coalition. The etiology and the developmental biology of the anomaly are still not fully understood. Here, we review the previous classification systems, present the clinical features, and discuss the developmental biology of PALH.