Patient Characteristics and Postoperative Outcomes of Surgically Treated Inferior Pole Patellar Sleeve Fractures.

BACKGROUND: Despite representing over half of all pediatric patella fractures, inferior pole patellar sleeve fractures (PSFs) are a relatively uncommon pediatric injury. As a result, existing literature on PSFs is limited to case reports and small case series. The purpose of this study was to evaluate the radiographic and clinical characteristics of operatively treated PSFs as well as outcomes following surgical management. METHODS: A retrospective review of all inferior pole PSFs requiring surgery from 2007 to 2023 was performed at a single urban tertiary care children's hospital. Cases were identified using diagnostic and billing codes. Patient demographics, injury characteristics, surgical techniques, and postoperative rehabilitation practices were recorded. Regional skeletal maturity, fracture characteristics, and postreduction patellar height were recorded. Postoperative complications were recorded and categorized using the modified Clavien-Dindo Classification System (CDS). RESULTS: Thirty-eight inferior pole PSFs were identified meeting study criteria. The majority of patients were male (86.8%), and the mean age at injury was 11.0 years (range: 7.2 to 15.0). Mean BMI was 21.1. Radiographically, the majority of patients were Epiphyseal Fusion Stage 0 (nonunion), with a median postreduction Caton-Deschamps index (CDI) of 1.2 (IQR: 1.1 to 1.3). These fractures were predominantly treated with suture-based fixation (84%). Postoperative immobilization varied within the cohort, and the initiation of knee ROM was permitted at a median of 3.5 (IQR: 2.0 to 4.6) weeks. All patients regained full range of motion and straight leg raise without extensor lag, and return-to-sport was achieved by a median of 17.6 weeks (IQR: 12.8 to 30.3). Complications occurred in 10 (26.3%) patients, with 3 (7.9%) requiring a return to the OR (CDS Grade III). CONCLUSIONS: Inferior pole PSFs appear to occur most commonly among prepubertal males of normal BMI and normal patellar height. Despite variable rehabilitation protocols, operative management resulted in restoration of extensor mechanism function. Eight percent of patients experienced complications requiring unplanned surgery. This large series improves our understanding of the epidemiology, injury characteristics, and postoperative outcomes of an operatively treated cohort of a rare injury pattern. LEVEL OF EVIDENCE: Level IV.

Patellar osteochondritis dissecans: maturation-dependent patellofemoral joint characteristics.

BACKGROUND: The likelihood of healing of osteochondritis dissecans decreases with skeletal maturity and there are theories that abnormal biomechanical forces contribute to the development and progression of these lesions. OBJECTIVE: To characterize, according to regional skeletal maturity, the morphology and alignment indices of the patellofemoral joint on MRI in patients with patellar osteochondritis dissecans. MATERIALS AND METHODS: MRI examinations of patients with patellar osteochondritis dissecans obtained between January 2008 and May 2023 were retrospectively reviewed to determine regional skeletal maturity, osteochondritis dissecans lesion size and location, patellar and trochlear morphology (Wiberg/Dejour classifications), and to calculate trochlear sulcus angles, trochlear depth index, lateral trochlear inclination, Insall-Salvati index, Caton-Deschamps index, patellar tendon-lateral trochlear ridge, and tibial tubercle-trochlear groove distances. Values were compared between skeletally immature and mature groups. RESULTS: Sixty-eight children (22 girls, 46 boys, age: 14.0 ± 1.7 years) yielded 74 knees with patellar osteochondritis dissecans lesions, 14 (19%) of which were skeletally mature. The most common anatomic location was over the central patella [median ridge (34/74 - 46%) on the axial images and over the middle third (45/74 - 61%) on the sagittal images]. Overall, mean trochlear sulcus angle (high, 151 ± 11°), trochlear depth index (low, 2.8 ± 1.4 mm), and Insall-Salvati index (borderline, 1.3 ± 0.1) were abnormal for the entire sample. Skeletally mature knees were significantly more likely to have higher (more dysplastic) Dejour types when compared to skeletally immature knees (p < 0.01). Knees in the mature group, compared to immature, had significantly more abnormal mean lateral trochlear inclination (15 ± 8° vs. 19 ± 6°, p = 0.03) and patellar tendon-lateral trochlear ridge distance (5.55 ± 4.31 mm vs. 2.89 ± 4.69 mm, p = 0.04). Half of the knees had ≥ 4 abnormal features that predispose to patellofemoral maltracking; mature knees were significantly (p = 0.02) more likely to have a higher number of abnormal features (> 6 features, 7/14, 50.0%) versus immature knees (0-3 features, 33/60, 55.0%). CONCLUSION: In children with patellar osteochondritis dissecans, abnormal patellofemoral morphology and alignment indices were common in all patients and more severe in mature knees.

Pediatric foot fractures on radiographs: distribution and predictors of surgery.

PURPOSE: To examine the distribution and characteristics of pediatric foot fractures on radiographs with respect to age and skeletal maturation, and to identify predictors of surgery. METHODS: This retrospective study included children (≤ 18 years) with foot fractures, who underwent radiographic examinations (2020-2022). Electronic medical records were reviewed to obtain demographic and clinical data. Fracture characteristics, including anatomic location, presence of displacement, angulation, articular involvement, and, if skeletally immature, physeal involvement and Salter-Harris fracture pattern were collected. Logistic regression models were used to identify predictors of surgery. RESULTS: 1,090 (596-boys, 494-girls; mean age, 11.0 ± 4.0 years) patients with 1,325 (59.8% metatarsal, 33.8% phalangeal, and 6.4% tarsal) fractures were included. Fractures of 1st metatarsal were more common among younger children whereas fractures of 2nd-4th and 5th metatarsals were more common among older children (median ages: 5.9 years vs. 10.3 years and 12.4 years, p < 0.001). Intra-articular fractures were more common among maturing and mature than immature bones (25.3% and 20.4% vs. 9.9%, p < 0.001). Physeal involvement was uncommon (162/977, 16.6%) and the most common pattern was Salter-Harris type II (133/162, 82.1%). A minority (47/1090, 4.3%) of patients required surgery and independent predictors of surgery included physeal involvement (OR = 5.12, 95% CI: 2.48-10.39, p < 0.001), multiple fractures (OR = 3.85, 95% CI: 1.67-8.53, p = 0.001), fracture displacement (OR = 9.16, 95% CI:4.43-19.07, p < 0.001), and articular involvement (OR = 2.72, 95% CI:1.27-5.72, p = 0.008). Using these predictors, the likelihood for surgery ranged between 8.0% with 1 and 86.7% with 3 predictors. CONCLUSION: Pediatric foot fracture patterns differed based on age and regional skeletal maturation. Physeal involvement, multiple fractures, fracture displacement, and articular involvement were independent predictors of surgery in our study group.

Pediatric thrower's elbow: maturation-dependent MRI findings in symptomatic baseball players.

BACKGROUND: Elbow pain is common among youth baseball players and elbow MRI is increasingly utilized to complement the clinical assessment. OBJECTIVE: To characterize, according to skeletal maturity, findings on elbow MRI from symptomatic youth baseball players. MATERIALS AND METHODS: This IRB-approved, HIPAA-compliant retrospective study included pediatric (<18 years of age) baseball players with elbow pain who underwent MRI examinations between 2010 and 2021. Two radiologists, blinded to the outcome, independently reviewed examinations to categorize skeletal maturity and to identify osseous and soft tissue findings with consensus used to resolve discrepancies. Findings were compared between skeletally immature and mature patients and logistic regression models identified predictors of surgery. RESULTS: This study included 130 children (115 boys, 15 girls): 85 skeletally immature and 45 mature (12.8±2.3 and 16.2±1.0 years, respectively, p<0.01). Kappa coefficient for interobserver agreement on MRI findings ranged from 0.64 to 0.96. Skeletally immature children, when compared to mature children, were more likely to have elbow effusion (27%, 23/85 vs 9%, 4/45; p=0.03), medial epicondyle marrow edema (53%, 45/85 vs 16%, 7/45; p<0.01), avulsion fracture (19%, 16/85 vs 2%, 1/45; p=0.02), and juvenile osteochondritis dissecans (OCD, 22%, 19/85 vs 7%, 3/45; p=0.04), whereas skeletally mature children were more likely to have sublime tubercle marrow edema (49%, 22/45 vs 11%, 9/85; p<0.01) and triceps tendinosis (40%, 18/45 vs 20%, 17/85; p=0.03). Intra-articular body (OR=4.2, 95% CI 1.5-47.8, p=0.02) and osteochondritis dissecans (OR=3.7, 95% CI 1.1-11.9, p=0.03) were independent predictors for surgery. CONCLUSION: Differential patterns of elbow MRI findings were observed among symptomatic pediatric baseball players based on regional skeletal maturity. Intra-articular body and osteochondritis dissecans were independent predictors of surgery.

Patella and Trochlea Osteochondritis Dissecans: Demographics and Treatment Paradigms.

OBJECTIVE: Previous research on patellar and trochlear groove osteochondritis dissecans (OCD) is limited by small sample sizes. This study aims to describe the presentation of patients with OCD lesions of the patella and trochlea and characterize the outcomes of operative and nonoperative treatments. METHODS: This retrospective cohort study identified all patients from a single institution from 2008 to 2021 with patellar and/or trochlear OCD lesions. Patients were excluded from the study if surgical records were unavailable or if the patient had knee surgery for a different injury at index surgery or in the 12 months postoperative. Minimum follow-up was 12 months. Outcomes included a return to sports (RTS), pain resolution, radiographic healing, and treatment "success" (defined as full RTS, complete pain resolution, and full healing on imaging). RESULTS: A total of 68 patients (75 knees) were included-45 (60%) with patellar OCD and 30 (40%) with trochlear. Of the patients, 69% were males. The median age at knee OCD diagnosis was 14 years. At the final follow-up, 62% of knees (n = 44) recovered sufficiently to allow a full RTS and 54% of knees (n = 39) had full pain resolution. Of the 46 knees with radiographic imaging at least 1 year apart, 63% had full healing of the lesion. There was no significant difference in RTS, pain resolution, radiographic healing, or overall success when comparing treatments. CONCLUSIONS: This study provides valuable epidemiologic demographic and outcome data regarding the scarcely reported patellar and trochlear OCD. While over half of patients fully returned to sports and reported full pain resolution, a large proportion continued to experience symptoms over a year after presentation. Future research should aim to better define the treatment algorithms for these OCD subtypes. LEVEL OF EVIDENCE: Level III.

Maturation-dependent patterns of knee injuries among symptomatic pediatric soccer players on MRI.

OBJECTIVE: To systematically investigate the prevalence of knee MRI findings among symptomatic pediatric soccer players with respect to skeletal maturity and to identify predictors of surgery. METHODS: This IRB-approved, HIPAA-compliant retrospective study included soccer players (< 18 years of age) who underwent MRI examinations in the past 5 years (2018-2023). Two radiologists retrospectively and independently reviewed all examinations to categorize skeletal maturity and to identify osseous and soft tissue findings. Findings were compared between maturation groups, and logistic regression models were used to identify predictors of surgery. RESULTS: Ninety-seven players (45 boys, 52 girls) included 39 skeletally immature, 21 maturing, and 37 mature knees. Kappa coefficient for interobserver reliability ranged between 0.65 and 1.00. Osgood-Schlatter disease (OSD) was more common among immature than maturing and mature knees (25% vs 14% and 5%, p = 0.04); anterior cruciate ligament (ACL) injury was more common among maturing and mature than immature knees (59% and 48%, vs 15%, p < 0.01); and meniscal tears were more common among mature than immature and maturing knees (medial, 41% vs 18% and 14%, p = 0.03; lateral, 43% vs 21% and 19%, p = 0.04). Players in the mature group were more likely to undergo surgery (p = 0.01). The presence of an effusion (OR = 19.5, 95% CI 2.8-240.9, p = 0.01), ACL injury (OR = 170.0, 95% CI 1.3-6996.9, p < 0.01), and lateral meniscal tears (OR = 10.8, 95% CI 1.8-106.1, p = 0.02) were independent predictors of surgery. CONCLUSION: Differential patterns of injury were found among symptomatic pediatric soccer players; the presence of an effusion, ACL injury, and lateral meniscal tears were independent predictors of surgery, likely contributing to the higher rates of surgery among skeletally mature players.

Diffusion tensor imaging of the physis: the ABC's.

The physis, or growth plate, is the primary structure responsible for longitudinal growth of the long bones. Diffusion tensor imaging (DTI) is a technique that depicts the anisotropic motion of water molecules, or diffusion. When diffusion is limited by cellular membranes, information on tissue microstructure can be acquired. Tractography, the visual display of the direction and magnitude of water diffusion, provides qualitative visualization of complex cellular architecture as well as quantitative diffusion metrics that appear to indirectly reflect physeal activity. In the growing bones, DTI depicts the columns of cartilage and new bone in the physeal-metaphyseal complex. In this "How I do It", we will highlight the value of DTI as a clinical tool by presenting DTI tractography of the physeal-metaphyseal complex of children and adolescents during normal growth, illustrating variation in qualitative and quantitative tractography metrics with age and skeletal location. In addition, we will present tractography from patients with physeal dysfunction caused by growth hormone deficiency and physeal injury due to trauma, chemotherapy, and radiation therapy. Furthermore, we will delineate our process, or "DTI pipeline," from image acquisition to data interpretation.

Outcomes following Free Fibula Physeal Transfer for Pediatric Proximal Humerus Reconstruction: An International Multi-Institutional Study.

BACKGROUND: Vascularized fibula epiphyseal flap was first described in 1998 for proximal humeral reconstruction in children/infants. The authors aim to review their international, multi-institutional, long-term outcomes. METHODS: An international, multi-institutional review (2004 to 2020) was conducted of patients younger than 18 years undergoing free vascularized fibula epiphyseal transfer for proximal humeral reconstruction. Donor- and recipient-site complications, pain, and final ambulatory status were reviewed. Growth of the transferred bone was assessed under the guidance of a pediatric musculoskeletal radiologist. RESULTS: Twenty-seven patients were included with a median age of 7 years (range, 2 to 13 years). Average follow-up was 120 ± 87.4 months. There were two flap failures (7.4%). Recipient-site complications included fracture [ n = 11 (40.7%)], avascular necrosis of the fibula head [ n = 1 (3.7%)], fibular head avulsion [ n = 1 (3.7%)], infection [ n = 1 (3.7%)], and hardware failure [ n = 1 (3.7%)]. Operative fixation was necessary in one patient with a fracture. The case of infection necessitated fibula explantation 2 years postoperatively, and ultimately, prosthetic reconstruction. Sixteen patients developed peroneal nerve palsy (59.3%): 13 of these cases resolved within 1 year (81% recovery), and three were permanent (11.1%). One patient (3.7%) complained of upper extremity pain. Longitudinal growth was confirmed in all but three cases [ n = 24 (88.9%)] at an average rate of 0.83 ± 0.25 cm/year. CONCLUSIONS: The vascularized fibula epiphysis for proximal humerus reconstruction in children preserves the potential for future growth and an articular surface for motion. Peroneal nerve palsy is common following harvest, although this is often transient. Future efforts should be geared toward reducing postoperative morbidity. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

MRI findings of growth plate fractures of the knee: are there age- and fracture-dependent differences?

OBJECTIVE: To investigate MRI findings in children with physeal fractures of the knee with respect to age, location, and articular involvement. METHODS: Children with physeal fractures who underwent knee MRI between 2008 and 2021 were included. Two radiologists retrospectively reviewed all examinations to determine articular involvement, findings of physeal instability (perichondral disruption, periosteal entrapment), and internal derangement (cruciate ligament injury, meniscal tear, chondromalacia). Independent samples t, Mann-Whitney U, Pearson's chi-square, and Fisher's exact tests were used to compare findings. RESULTS: Fifty-six patients (37 boys, 19 girls; mean age: 12.2 ± 2.5 years; 32 distal femur, 24 proximal tibial fractures) included 24(43%) intraarticular fractures. Fractures were more common in the tibia than the femur (67% versus 25%, p = 0.004) and intraarticular fractures were more common in older than younger children (13.1 ± 2.0 versus 11.5 ± 2.7 years, p = 0.01), to associate with chondromalacia (46% versus 12%, p = 0.02) and undergo surgery (33% versus 10%, p = 0.04) when compared to extraarticular fractures. Perichondral disruption (n = 44, 79%) and periosteal entrapment (n = 13, 23%) did not significantly differ based on location or articular involvement (p > 0.05). At a median follow-up of 17.5 months (interquartile range: 1.25-34), 3 patients (2 intraarticular, 1 extraarticular fractures) developed osteoarthritis, osteochondral lesion, and leg-length discrepancy from growth arrest, which required additional surgery. CONCLUSION: Intraarticular physeal fractures were more common with older children, associate with chondromalacia, and underdo surgical intervention when compared to extraarticular fractures of the knee. While MRI findings of physeal instability were common, no significant differences were found between fractures based on anatomic location or fracture pattern.

Distribution of pediatric hand fractures: age- and bone maturation-dependent differences.

PURPOSE: To investigate the distribution and characteristics of fractures of bones of the hand on radiographs with respect to age and skeletal maturity of the fractured bone, and to identify predictors of surgery. METHODS: This cross-sectional, retrospective study included children (≤ 18 years) with hand fractures who underwent radiographic examinations (2019-2021). Fracture location, presence of displacement (≥ 2 mm), angulation (≥ 10°), articular extension, and if skeletally immature, then physeal involvement and Salter-Harris grade were recorded. Mann-Whitney U, Kruskal-Wallis, Fisher's exact, and chi-square tests as well as logistic regression analyses were used. RESULTS: Study group of 508 (350 boys, 158 girls; median age, 11.9 years) included 575 (63% phalangeal, 37% metacarpal, and 0.3% carpal) fractures. Younger children were more likely to sustain phalangeal and older children carpal and metacarpal fractures (median ages: 10.8 vs 12.3 and 13.8 years, p < 0.001); and fractures of the small finger accounted for 50% of metacarpal and 43% of phalangeal fractures. Fracture displacement (12% vs 22%, p = 0.02) and angulation (25% vs 49%, p < 0.001) were more common with mature than immature bones. A third of immature bones had physeal involvement and the most common pattern was Salter-Harris type II (89%). Surgical intervention was uncommon (11%) and independent predictors were displacement (OR = 3.99, 95% CI 1.95-8.19, p < 0.001) and articular extension (OR = 5.11, 95% CI 2.00-13.07, p < 0.001). CONCLUSION: While younger children were more likely to sustain phalangeal than metacarpal fractures and less likely to have displacement and angulation when compared to older children; only displacement and articular extension were significant independent predictors of surgery.

Radiographic Evaluation of Pediatric Patients with Patellofemoral Instability.

PURPOSE OF REVIEW: The purpose of this review is to highlight the radiographic assessments of utility in the evaluation of a pediatric patient with patellofemoral instability to facilitate a thorough work-up. Understanding of these measures is useful in understanding evolving research in this field, providing accurate patient risk assessment, and appropriately directing surgical decision-making. RECENT FINDINGS: Recent literature has broadened the radiographic characterization of the pediatric patellar instability and its anatomic risk factors. Knee MRI can inform the assessment of skeletal maturity and novel axial alignment measurements may enhance our identification of patients at increased risk of recurrent instability. Additional improvements have been made in the objective measurement and classification of trochlear dysplasia. Knee MRI-based skeletal age assessments may obviate the need for hand bone age assessments in growing children with patellofemoral instability. Novel objective measures exist in the evaluation of pediatric patellar instability both in the assessment of axial alignment and trochlear dysplasia. Future work should focus on how these measures can aid in guiding surgical decision-making.

Pediatric Osteosarcoma: Correlation of Imaging Findings with Histopathologic Features, Treatment, and Outcome.

Osteosarcoma is the most common primary bone sarcoma in children. Imaging plays a pivotal role in diagnostic workup, surgical planning, and follow-up monitoring for possible disease relapse. Survival depends on multiple factors, including presence or absence of metastatic disease, chemotherapy response, and surgical margins. At diagnosis, radiography and anatomic MRI are used to characterize the primary site of disease, whereas chest CT and whole-body bone scintigraphy and/or PET are used to identify additional sites of disease. Treatment starts with neoadjuvant chemotherapy, followed by en bloc tumor resection and limb reconstruction, and finally, adjuvant chemotherapy. Preoperative planning requires precise tumor delineation, which traditionally has been based on high-spatial-resolution anatomic MRI to identify tumor margins (medullary and extraosseous), skip lesions, neurovascular involvement, and joint invasion. These findings direct the surgical approach and affect the options for reconstruction. For skeletally immature children, the risk of cumulative limb-length discrepancy and need for superior longevity of the reconstruction have led to the advent and preferential use of several pediatric-specific surgical techniques, including rotationplasty, joint preservation surgery, autograft or allograft reconstruction, and extendible endoprostheses. A better understanding of the clinically impactful imaging features can directly and positively influence patient care. Online supplemental material is available for this article. ©RSNA, 2022.

MRI Predictors of Residual Dysplasia in Developmental Dysplasia of the Hip Following Open and Closed Reduction.

BACKGROUND: Following open or closed reduction for children with developmental dysplasia of the hip, there remains a significant risk of residual acetabular dysplasia which can compromise the long-term health of the hip joint. The purpose of this study was to use postoperative in-spica magnetic resonance imaging (MRI) data to determine factors predictive of residual acetabular dysplasia at short-term follow-up. METHODS: We retrospectively reviewed 63 hips in 48 patients which underwent closed or open reduction and spica casting for developmental dysplasia of the hip. MRI performed in-spica at ∼3-week follow-up were used to assess 11 validated metrics and 2 subjective factors. Acetabular index (AI) was measured on anteroposterior pelvic radiographs at 2-year postoperative follow-up. Binary logistic regression was then used to identify variables predictive of residual dysplasia, defined as an AI greater than the 90th percentile for age based on historic normative data. RESULTS: Average age at surgical reduction was 9.3±3.2 months. 58.7% (37/63) of reductions were open. A total of 43 (68.3%) hips demonstrated residual acetabular dysplasia at 2 years postoperatively based on normative values. In those with persistent dysplasia, patients were on average older at the time of reduction (10.0 mo±3.2 vs. 8.0 mo±2.8, P=0.010) and more likely female (88.4% vs. 60.0%, P=0.010). Patients with residual dysplasia were more likely to have mild subluxation on postoperative MRI (40.0% vs. 10.5%, P=0.022). Hips with a cartilaginous acetabular index (CAI) of >23 degrees were 7.6 times more likely to develop residual dysplasia. Type of reduction (ie, closed vs. open) did not appear to influence the rate of residual dysplasia (P=0.682). CONCLUSION: In this series, the rate of residual dysplasia after surgical reduction was higher than most previous reports, with no appreciable difference between closed and open reductions. Older age, female sex, and a higher CAI were associated with a greater risk of persistent radiographic dysplasia. In particular, hips with a CAI >23 degrees were 7.6 times more likely to be dysplastic at 2-year follow-up. LEVEL OF EVIDENCE: Level III.

MRI evaluation of pediatric tibial eminence fractures: comparison between conventional and "CT-like" ultrashort echo time (UTE) images.

OBJECTIVE: UTE MRI offers a radiation-free alternative to CT for bone depiction, but data on children is lacking. The purpose of this study was to determine whether UTE images improve detection and characterization of pediatric tibial eminence fractures. METHODS: Fifteen MRIs with UTE from 12 children (10 boys, 2 girls; mean age: 12.6 ± 3.3 years) with tibial eminence fractures (2018-2020) and 15 age-matched MRIs without fractures were included. After randomization, 5 readers reviewed images without and with UTE, at least 1 month apart, and recorded the presence of fracture and preferred images. If fracture is present, radiologists also recorded fragment size, number, and displacement; surgeons assigned Meyers-McKeever grade and management. Disagreements on management were resolved through consensus review. Kappa and intra-class correlation (ICC), sensitivity, and specificity were used to compare agreement between readers and fracture detection between images without and with UTE. RESULTS: For fracture detection, inter-reader agreement was almost perfect (κ-range: 0.91-0.93); sensitivity and specificity were equivalent between images without and with UTE (range: 95-100%). For fracture characterization, UTE improved agreement on size (ICC = 0.88 to 0.93), number (ICC = 0.52 to 0.94), displacement (ICC = 0.74 to 0.86), and grade (ICC = 0.92 to 0.93) but reduced agreement on management (κ = 0.68 to 0.61), leading to a change in consensus management in 20% (3/15). Radiologists were more likely to prefer UTE for fracture and conventional images for non-fracture cases (77% and 77%, respectively, p < 0.001). CONCLUSION: While UTE did not improve diagnosis, it improved agreement on characterization of pediatric tibial eminence fractures, ultimately changing the preferred treatment in 20%.

Primary Periphyseal Stress Injuries in Young Athletes: A Systematic Review.

BACKGROUND: Overuse injuries are common in sporting children and adolescents. These injuries are a particular concern when they involve the epiphyseal-physeal-metaphyseal (EPM) complex given their potential to disturb skeletal growth. Specifically, the limits of mechanical tolerance of the EPM complex to repetitive stress may be exceeded by the intense and continuous training characteristic of many youth sports today. OBJECTIVE: This article describes the present status of knowledge on the occurrence and outcome of primary periphyseal stress injuries (PPSIs) affecting the EPM complex in the extremities of children and adolescents involved in youth sports. METHODS: A comprehensive review of the sports medicine literature was conducted to determine the nature and extent of PPSIs affecting the EPM complex of the extremities among youth sports participants and the potential for consequent skeletal growth disturbance and resultant limb deformity associated with these injuries. RESULTS: Our initial search uncovered 128 original published scientific articles reporting relevant data on PPSIs. There were 101 case reports/series, 19 cross-sectional, 1 case-control, and 7 cohort studies with relevant data. The case reports/series studies reported 448 patients with PPSIs involving the extremities. Children and adolescents representing a variety of high impact repetitive youth sports activities-including baseball, badminton, climbing, cricket, dance, gymnastics, rugby, soccer, swimming, tennis, and volleyball-may sustain PPSIs involving the shoulder, elbow, hand and wrist, knee, and ankle and foot. Although incidence data from prospective cohort studies are lacking, data arising from cross-sectional studies suggest that PPSIs may be common in select groups of youth athletes-including the shoulder in baseball players (0-36.6%), wrist in gymnasts (10-83%) and platform divers (52.6%), and fingers in rock climbers (5-58%). Notably, not all stress-related skeletal changes detected on imaging were symptomatic in these studies. When diagnosed and treated with an appropriate period of rest and rehabilitation, most patients studied were able to return to their sport activities. However, our data also show that 57/448 PPSIs (12.7%) produced growth disturbance, and that 28/448 patients (6.2%) underwent surgery for their injuries. Absence of treatment, delayed presentation and diagnosis, and non-compliance with a rest regimen were common in cases that produced growth disturbance. CONCLUSIONS: PPSIs may affect the extremities of children and adolescents engaged in a variety of youth sports, especially at advanced levels of training and competition. Most skeletally immature patients with PPSIs respond well to timely treatment; however, in extreme cases, PPSIs can progress to produce skeletal growth disruption which may necessitate surgical intervention. Clearly, establishing the early diagnosis of PPSIs and providing timely treatment of these injuries are needed to ensure the skeletal health of youth sports participants. Rigorous prospective longitudinal epidemiological and imaging studies designed to provide incidence rates of PPSIs and to determine the effect of PPSIs on long-term skeletal health are also necessary.

Descriptive Epidemiology From the Research in Osteochondritis Dissecans of the Knee (ROCK) Prospective Cohort.

BACKGROUND: Osteochondritis dissecans (OCD) occurs most commonly in the knees of young individuals. This condition is known to cause pain and discomfort in the knee and can lead to disability and early knee osteoarthritis. The cause is not well understood, and treatment plans are not well delineated. The Research in Osteochondritis Dissecans of the Knee (ROCK) group established a multicenter, prospective cohort to better understand this disease. PURPOSE: To provide a baseline report of the ROCK multicenter prospective cohort and present a descriptive analysis of baseline data for patient characteristics, lesion characteristics, and clinical findings of the first 1000 cases enrolled into the prospective cohort. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Patients were recruited from centers throughout the United States. Baseline data were obtained for patient characteristics, sports participation, patient-reported measures of functional capabilities and limitations, physical examination, diagnostic imaging results, and initial treatment plan. Descriptive statistics were completed for all outcomes of interest. RESULTS: As of November 2020, a total of 27 orthopaedic surgeons from 17 institutions had enrolled 1004 knees with OCD, representing 903 patients (68.9% males; median age, 13.1 years; range, 6.3-25.4 years), into the prospective cohort. Lesions were located on the medial femoral condyle (66.2%), lateral femoral condyle (18.1%), trochlea (9.5%), patella (6.0%), and tibial plateau (0.2%). Most cases involved multisport athletes (68.1%), with the most common primary sport being basketball for males (27.3% of cases) and soccer for females (27.6% of cases). The median Pediatric International Knee Documentation Committee (Pedi-IKCD) score was 59.9 (IQR, 45.6-73.9), and the median Pediatric Functional Activity Brief Scale (Pedi-FABS) score was 21.0 (IQR, 5.0-28.0). Initial treatments were surgical intervention (55.4%) and activity restriction (44.0%). When surgery was performed, surgeons deemed the lesion to be stable at intraoperative assessment in 48.1% of cases. CONCLUSION: The multicenter ROCK group has been able to enroll the largest knee OCD cohort to date. This information is being used to further understand the pathology of OCD, including its cause, associated comorbidities, and initial presentation and symptoms. The cohort having been established is now being followed longitudinally to better define and elucidate the best treatment algorithms based on these presenting signs and symptoms.

Magnetic resonance imaging findings of synovial sarcoma in children: location-dependent differences.

BACKGROUND: While overall survival for children is greater than that for adults, synovial sarcoma remains an aggressive neoplasm with a potentially poor prognosis, and its magnetic resonance imaging (MRI) findings in children are not well described. OBJECTIVE: We aimed to characterize the spectrum of MRI findings of synovial sarcoma in children with respect to anatomical location and outcome. MATERIALS AND METHODS: Children with histologically confirmed synovial sarcoma and preoperative MRI performed within the past 11 years (2009-2020) were included. Two radiologists retrospectively reviewed each MRI to categorize location, signal characteristics and associated findings. Chi-square and Fisher exact tests were used to assess associations with locations and outcomes. RESULTS: This study included 23 children (13 girls, 10 boys; mean age: 12.7±4.2 years) with 7 axial, 8 proximal and 8 distal appendicular lesions. Kappa ranged from 0.53 to 1. MRI findings differed significantly between locations with axial lesions measuring larger (P=0.01) and more likely to contain fluid levels (P=0.02), triple sign (P=0.02), inhomogeneous signal (T1-weighted images, P=0.003; T2-weighted images, P=0.02, contrast-enhanced images, P=0.03) with all lesions containing partially solid composition (P=0.03). At a median follow-up of 14 months (interquartile range: 7-33 months), 39% relapsed. Predictors of relapse (P<0.05) included metastasis at presentation, larger lesions, axial lesions and MRI findings of fluid level, T1-weighted hyperintensity, inhomogeneous signal (T1- and T2-weighted images) and poorly circumscribed margins. CONCLUSION: A significant association was found between location and MRI findings in our cohort of children with synovial sarcoma. Axial lesions were more likely to be larger, appear heterogeneous and be associated with a worse outcome.

Does Surgical Experience Decrease Radiation Exposure in the Operating Room?

BACKGROUND: Intraoperative fluoroscopy facilitates minimally invasive surgery, and although it is irreplaceable in terms of intraoperative guidance, it results in substantial radiation exposure to the patient and surgical team. Although the risk of radiation exposure because of equipment factors has been described, there is little known about the impact of surgeon experience on radiation exposure. The aim of this study was to determine whether there is a relationship between years of surgical experience and total dose of radiation used for an archetypal pediatric orthopaedic surgical procedure that requires intraoperative fluoroscopy. METHODS: This was a retrospective cohort study of children undergoing closed reduction and percutaneous pinning for supracondylar humerus fractures at a level I pediatric trauma center. Information pertaining to radiation dosage was gathered including fluoroscopic time, total images acquired, magnification use, and dose area product (DAP). Regression analysis was used to evaluate the effect of surgeon experience on the outcome variables. RESULTS: A total of 759 pediatric patients treated by 17 attending surgeons were included. The median surgeon experience was 8.94 years (interquartile range, 5.9 to 19.8). Increased number of pins was associated with increased DAP (P<0.001) and lower years of experience (P=0.025). There was significantly higher fluoroscopy time in seconds (56.9 vs. 42.1 s, P=0.001), DAP (179.9 vs. 110.3 mGy-cm2, P=0.001), use of magnification (39.5 vs. 31.9 s, P=0.043), and total number of images obtained (74.5 vs. 57.6, P=0.008) in attending surgeons with <1 year of experience compared with those with greater experience. An operator extremity was visible in at least 1 saved image in 263 of 759 (35%) cases. CONCLUSION: Increased surgical experience was significantly associated with decreased fluoroscopy usage, including time, number of images, and dose. Surgeon inexperience increases radiation exposure for patients and staff by over 60% when treating supracondylar humerus fractures. This study clearly identifies methods to reduce radiation exposure, including use of pulsed fluoroscopy instead of continuous fluoroscopy, decreasing use of magnification, removing the operator's extremity from the field, and judicious use and placement of each additional pin. LEVEL OF EVIDENCE: Level III.

Nonossifying Fibroma of the Distal Tibia: Predictors of Fracture and Management Algorithm.

BACKGROUND: Nonossifying fibroma (NOF) is a common benign lesion in children and adolescents. This study investigated the risk of pathologic fracture in NOF lesions of the distal tibial based on anatomic location, clinical symptomatology, and imaging features, in order to propose an algorithm for the management of such lesions. METHODS: In an IRB-approved retrospective case-control study, all patients diagnosed with NOF between 2010 and 2017 were extracted from our database. Patients below 18 years of age at the time of diagnosis and with lesions involving the distal tibia were included. Demographic data, the reason for visit, and the mechanism of injury were recorded. Radiographs were reviewed to record the size (absolute and relative to bone width) and location of each lesion. Computed tomography and magnetic resonance imaging examinations were also reviewed when available. Two authors graded all lesions using the Ritschl classification and determined the presence of 2 novel signs: the syndesmosis sign and the Pac-Man sign. RESULTS: A total of 84 patients were included in the final analysis, of which 25 were in the fracture group and 59 in the nonfracture group. None of the patients in the fracture group was previously diagnosed with NOF, but nine (36%) patients had symptoms for >6 months preceding the fracture. Ankle sprain was the most common reason for visit in the nonfracture group. The lateral location of the lesion in the distal tibia (P=0.001), size (P<0.001 for both absolute and relative values), Ritschl stage (P=0.003), syndesmosis sign (P=0.005), and the Pac-Man sign (P=0.002) were significant predictors of fracture. All measurements had almost-perfect to perfect inter-rater agreements. CONCLUSIONS: The most significant imaging risk factors for fracture are a larger size, Ritschl stage B, and the presence of cortical thinning on anteroposterior or lateral radiographs. We introduced 2 signs for these distal tibial NOFs, a scoring system, and a management algorithm that is based on radiographs alone but incorporates advanced imaging findings in equivocal cases. LEVEL OF EVIDENCE: Therapeutic Level III-case-control study.

Do Not Miss the Tumor: A Novel Presentation of Osteosarcoma.

Antalgic gait is a common clinical presentation among pediatric patients and can have many different etiologies, with rare life-threatening etiologies including primary bone malignancies. Osteosarcoma is the most common primary malignancy of bone in pediatric and adolescent patients. The incidence rate of osteosarcoma has been reported as high as 5 to 7 per million among patients 19 years old or younger with males slightly more affected than females and African-Americans more than other racial groups. This report describes the case of a five-year-old African-American female who presented with an antalgic gait secondary to osteosarcoma in the left distal femur and follows her through treatment. In this case, the age is atypical as the peak incidence for osteosarcoma is around 16 years of age and is postulated to coincide with growth spurts. Osteosarcoma can have a range of presentations making it difficult to diagnose, which can cause delays in treatment and potential poor patient outcomes. Due to this, such a diagnosis must be included in the differential for patients presenting with antalgic gait. Because primary-care physicians and pediatricians may be the first medical providers to encounter patients with osteosarcoma, it is imperative that such clinicians are familiar with the signs and symptoms associated with osteosarcomas in order to reduce the risk of metastasis and disease progression and prevent treatment delays. Additionally, we believe these clinicians should have a low threshold to refer patients to orthopedists or oncologic specialists in the cases of persistent pain or inconsistencies with history, physical exam, and diagnostic studies. Finally, direct communication and discussion between radiologists and referring clinicians helps decrease delays in diagnosing of osteosarcoma and other life-threatening conditions.