Developmental dysplasia of the hip and ultrasound reading by pediatric orthopedic surgeons: a pilot study

Ultrasound is an imaging modality utilized for early detection and follow-up of developmental dysplasia of the hip (DDH) in infants. Traditionally, pediatric orthopedic surgeons have relied on radiologists to perform ultrasound examinations and interpret the imaging. Today, however, many orthopedic surgeons are performing and interpreting ultrasound themselves. The purpose of this paper was to evaluate the reliability of pediatric orthopedic surgeons in interpreting ultrasound imaging of infant hips. This was a prospective observational pilot study. After reading an instructional handout about the Graf method of hip ultrasonography, eight pediatric orthopedic surgeons measured 28 hip ultrasound images to determine the alpha angle and percent femoral head coverage. On the basis of cited intraclass correlation coefficient cutoff values, interrater reliability was found to be 'good' for percent femoral head coverage and 'fair' for alpha angle. These findings are equivalent to findings of similar studies using radiologists as examiners. Pediatric orthopedic surgeons can interpret ultrasound exams for diagnosing DDH.

Abstract LB518: Osteochondromas respond and its development is inhibited by retinoic acid nuclear receptor gamma agonist treatment

Osteochondromas (OC) are cartilage-capped tumors that arise near growing physis and are considered the most common benign bone tumor in children. They can lead to skeletal deformity, pain, loss of motion and neurovascular compression. Occasionally, malignant degeneration can occur. OC is thought to arise by mysregulation of chondrogenesis or chondrocyte differentiation, leading to ectopic cartilage formation. OC can occur as a solitary or multiple OC (MO). MO can occur from a hereditary cancer syndrome in which EXT1 and EXT2 are the major causative genes. Currently, treatment is limited to surgical resection only. There are no available FDA-approved therapies for MO. Previous translational research suggested that retinoic acid nuclear receptor gamma agonist (RARγ) suppresses ectopic cartilage formation including OC in rodent models. These preclinical studies led to a clinical trial to study the efficacy and safety of Palovarotene, a RARγ agonist, for the systemic treatment of MO (NCT03442985). The clinical trial was terminated due to concerns of skeletal toxicity observed in pediatric patients. To overcome this adverse action, we should elucidate the molecular action of RARγ agonists on osteochondromas and refine the treatment regimen. The purposes of our study are to examine the mechanism in which RARγ elicits osteochondroma growth and to determine whether the responsiveness to RARγ agonists is different between OC and growth plate. Treatment of RARγ agonists on mouse chondrocytes stimulated cell death induced by hydrogen peroxide (H2O2). In addition, human OC explants treated with RARγ agonists contained more apoptotic cells than vehicle-treated OC explants. OCs were induced in AcanCreER; Ext1e2neofl/e2neofl MO mouse model via tamoxifen induction at P5. After two weeks, mice were treated with Palovarotene (1.76 mg/Kg) or corn oil, and 24hrs after treatment, forelimbs were harvested. In-situ hybridization analysis revealed that Palovarotene-treated OC had much more transcripts of Cyp26b1 (retinoid target gene) as compared with the corn oil-treated OC and that OCs had significantly higher response to Palovarotene compared to the adjacent growth plate. When Palovarotene (1.76 mg/Kg, daily) treatment continued for 2 weeks, OC development was greatly suppressed compared to vehicle control in the wrists and ribs as determined by histological staining and radiological assessments, whereas the Palovarotene-treated growth plate did not show histological abnormality. Together, these findings indicate that OC have higher sensitivity to RARγ agonist compared to the growth plate and RARγ agonists rapidly inhibits OC development without a significant negative effect on growth plate and may exert anti-tumor function on OC by inducing cell death via apoptosis.

Citation Format: Sonia Garcia, Hongying Tian, John Herzenberg, Joshua Abzug, Vincent Ng, Ashley Cellini, Masahiro Iwamoto, Motomi Enomoto-Iwamoto. Osteochondromas respond and its development is inhibited by retinoic acid nuclear receptor gamma agonist treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB518.

Prevalence of Ulnar Artery Thrombosis in Orthopedic Surgeons

Ulnar artery thrombosis (UAT) occurs most commonly in athletes and manual laborers who repeatedly use their palm in high-impact activities. Anecdotal evidence has shown an increased prevalence of UAT in orthopedic surgeons, especially in joint arthroplasty surgeons, compared with the general population. This study sought to determine the prevalence of UAT among orthopedic surgeons and to identify risk factors for developing UAT. Eighty orthopedic surgeons and residents were included in the study. Participants completed a demographic questionnaire, and a timed Allen test was performed on each hand with the radial artery occluded. A reperfusion result greater than 6 seconds was considered abnormal. Participants with a positive Allen test and UAT-associated symptoms were deemed to have UAT. Statistical analysis was performed using the Fisher exact and Wilcox-on rank-sum tests. The prevalence of UAT was 11% (9 of 80) in the study population compared with 1.6% (21 of 1300) in the general population (P<.0001). For surgeons with 15 years or more of practice, the UAT rate was 24% (8 of 33) compared with 2% (1 of 47) for surgeons with less than 15 years of practice (P=.0030). The prevalence of UAT in adult reconstruction surgeons trended toward significance at 40% (2 of 5) compared with 9% (7 of 75) in the other subspecialties (P=.095). Orthopedic surgeons have an increased risk for developing UAT compared with the general population. The risk of UAT is significantly correlated with advancing years in clinical practice and may be associated with the number of arthroplasty cases performed. [Orthopedics. 2019; 42(5):e415-e422.].

A Five-year Review of the Designated Leadership Positions of Pediatric Orthopaedic Society of North America: Where Do Women Stand?

Despite the growing number of women entering medical school, female representation among orthopedic surgery is the lowest compared with all areas of medicine. In 2014, 47.7% of students entering medical school were women, but only 13.7% of orthopedic residents were women. Pediatric orthopedics have been successful in enrolling women compared with other orthopedic subspecialties. This is an investigation of female representation among the Pediatric Orthopaedic Society of North America membership roster, providing insight into the effect on the increased gender diversity in the membership of an organization and its correlation with leadership positions at different levels within the organization.

Avoiding Errors in the Management of Pediatric Polytrauma Patients

Management of pediatric polytrauma patients is one of the most difficult challenges for orthopaedic surgeons. Multisystem injuries frequently include complex orthopaedic surgical problems that require intervention. The physiology and anatomy of children and adolescent trauma patients differ from the physiology and anatomy of an adult trauma patient, which alters the types of injuries sustained and the ideal methods for management. Errors of pediatric polytrauma care are included in two broad categories: missed injuries and inadequate fracture treatment. Diagnoses may be missed most frequently because of a surgeon's inability to reliably assess patients who have traumatic brain injuries and painful distracting injuries. Cervical spine injuries are particularly difficult to identify in a child with polytrauma and may have devastating consequences. In children who have multiple injuries, the stabilization of long bone fractures with pediatric fixation techniques, such as elastic nails and other implants, allows for easier care and more rapid mobilization compared with cast treatments. Adolescent polytrauma patients who are approaching skeletal maturity, however, are ideally treated as adults to avoid complications, such as loss of fixation, and to speed rehabilitation.

Pediatric Monteggia Fracture-Dislocations: Avoiding Problems and Managing Complications

Monteggia fracture-dislocations typically involve a dislocation of the radial head with an associated fracture of the ulnar shaft. The prompt diagnosis and treatment of these acute injuries result in excellent outcomes. Unfortunately, a Monteggia fracture-dislocation is often missed during diagnostic testing and results in a chronic Monteggia fracture-dislocation. The subsequent timing and treatment of chronic Monteggia fracture-dislocations are debatable because outcomes are suboptimal. Therefore, it is critical that the initial injury be correctly diagnosed and treated as close to the time of injury as possible to ensure excellent outcomes.

Open Reduction Techniques for Supracondylar Humerus Fractures in Children

Supracondylar humerus fractures are the most common elbow fractures in children. Displaced supracondylar humerus fractures that are associated with neurologic and/or vascular injuries should be treated with timely reduction via closed techniques. If closed reduction fails, reduction via open techniques is indicated. There is controversy about which surgical approach yields the best cosmetic and functional outcomes while minimizing postoperative complications. Open reduction, if indicated, has been reported to yield good outcomes in patients in whom closed reduction fails.

Transphyseal Distal Humerus Fracture

Transphyseal distal humerus fractures typically occur in children younger than 3 years secondary to birth trauma, nonaccidental trauma, or a fall from a small height. Prompt and accurate diagnosis of a transphyseal distal humerus fracture is crucial for a successful outcome. Recognizing that the forearm is not aligned with the humerus on plain radiographs may aid in the diagnosis of a transphyseal distal humerus fracture. Surgical management is most commonly performed with the aid of an arthrogram. Closed reduction and percutaneous pinning techniques similar to those used for supracondylar humerus fractures are employed. Cubitus varus caused by a malunion, osteonecrosis of the medial condyle, or growth arrest is the most common complication encountered in the treatment of transphyseal distal humerus fractures. A corrective lateral closing wedge osteotomy can be performed to restore a nearly normal carrying angle.

Current Strategies for the Management of Pediatric Supracondylar Humerus Fractures: Tips and Techniques for Successful Closed Treatment

Pediatric supracondylar humerus fractures are the most commonly encountered type of elbow fractures in children that require surgical fixation. Many pediatric supracondylar humerus fractures can be treated with closed reduction and percutaneous skeletal fixation. In difficult fractures, adjunct pin techniques, such as joystick wires and leverage pins, can be used to help attain a satisfactory and stable reduction before an open approach is used. After the fracture is reduced, optimal pinning, with the use of either crossed or lateral-entry techniques, and fixation that achieves maximal spread at the fracture site as well as bicortical engagement in both fragments are essential to maintain reduction and avoid complications that are associated with malunion. A practical approach as well as several tips and techniques may help surgeons attain and maintain stable closed reduction of pediatric supracondylar humerus fractures.

The Difficult Supracondylar Humerus Fracture: Flexion-Type Injuries

Although flexion-type supracondylar humerus fractures account for a minority of all supracondylar humerus fractures, they warrant special attention because of their relatively high rate of requirement for open reduction and their potential for ulnar nerve injury or entrapment. The severity of flexion-type supracondylar humerus fractures may be difficult to appreciate on initial radiographs; therefore, surgeons must have a high index of suspicion in the evaluation of a patient who has a suspected flexion-type supracondylar humerus fracture. Nondisplaced or minimally displaced flexion-type supracondylar humerus fractures can be treated with long arm casting. Displaced flexion-type supracondylar humerus fractures require surgical reduction and stabilization. The unique instability of and reduction position for flexion-type supracondylar humerus fractures make reduction and pinning more of a challenge compared with the more common extension-type supracondylar humerus fractures; therefore, special considerations are required in the surgical setup and planning for flexion-type supracondylar humerus fractures.

Common Errors in the Management of Pediatric Supracondylar Humerus Fractures and Lateral Condyle Fractures

Supracondylar humerus fractures and lateral condyle fractures are the two most common pediatric elbow fractures that require surgical intervention. Although most surgeons are familiar with supracondylar humerus fractures and lateral condyle fractures, these injuries present challenges that may lead to common errors in evaluation and management and, thus, compromise outcomes. It is well agreed upon that nondisplaced supracondylar fractures (Gartland type I) are best managed nonsurgically with cast immobilization. Errors may be made, however, in the treatment of type II fractures because the extent of displacement and instability are difficult to assess. Although some type II fractures are stable after closed reduction, many are not and benefit from closed reduction and percutaneous pinning to prevent late displacement and cubitus varus deformity. Stable fixation must be achieved and errors related to pin placement must be avoided to prevent the failure of type III fractures after closed reduction and percutaneous pinning. Many potential errors and pitfalls also are seen in the management of lateral condyle fractures. Radiographic assessment of displacement can be improved by obtaining an internal oblique view of the elbow. Surgical treatment with closed reduction and percutaneous pinning may be indicated for minimally displaced fractures (2 to 4 mm) that show evidence of increasing displacement over time or demonstrate intra-articular extension on an arthrogram. Displaced fractures are best treated with open reduction and internal fixation. Errors in surgical dissection, fracture reduction, and fixation are common and may result in osteonecrosis, malunion, and nonunion.