Prevalence of Femoroacetabular Impingement Morphology in Asymptomatic Adolescents.

BACKGROUND: Femoroacetabular impingement (FAI) can lead to acetabular chondrolabral damage and has been theorized as a causative factor in the development of osteoarthritis. The pathogenesis of FAI is unknown. The purpose of this study was to determine the prevalence of FAI morphology in asymptomatic adolescents. METHODS: We identified children 10 to 18 years of age who had undergone a pelvic CT between 2007 and 2012. Exclusion criteria included hip pain, any hip pathology, bone tumor, long-term steroid use, history of chemotherapy or radiation therapy, nonambulatory status, neuromuscular disorder, chromosomal abnormality, and metabolic bone disease. Multiplanar reformatted images were created from axial images to calculate α angles and lateral center-edge angles (LCEA). Cam morphology was defined as an α-angle ≥55 degrees and pincer morphology as a LCEA≥40 degrees. RESULTS: We analyzed 558 patients (1116 hips). There were 276 males and 282 females. The average age was 14.4 years (range, 10.0 to 18.2 y). The mean α-angle was 47.9 degrees (range, 25.7 to 78 degrees) and the mean LCEA was 34.4 degrees (range, 3.9 to 58.6 degrees). Males had a significantly higher mean α-angle (49.7 vs. 46.0 degrees) (P<0.0005) and females had a significantly higher mean LCEA (35.7 vs. 33.0 degrees) (P<0.0005). Ninety-four adolescents (16.8%) had an α-angle ≥55 degrees. Cam morphology was significantly more common in males (23.9% vs. 9.9%) (P<0.001). A total of 181 adolescents (32.4%) had a LCEA≥40 degrees. Pincer morphology was equally common in males and females (29.7% vs. 35.1%) (P=0.17). Thirty-four adolescents (6.1%) had mixed morphologies. Mixed morphologies were found in 21 males (7.6%) and 13 females (4.6%) (P=0.19). The prevalence of pincer morphology increased significantly with increased age in males (P<0.001). CONCLUSIONS: The prevalence of cam-type FAI morphology in asymptomatic adolescents is similar to the reported prevalence in asymptomatic adults. Pincer morphology may be more common than cam morphology in adolescents. Cam morphology is more prevalent in males, whereas pincer and mixed morphologies are equally prevalent in both sexes. LEVEL OF EVIDENCE: Level III-diagnostic.

Comparison of Effective Dose of Radiation During Pedicle Screw Placement Using Intraoperative Computed Tomography Navigation Versus Fluoroscopy in Children With Spinal Deformities.

BACKGROUND: We compared the effective dose of radiation associated with pedicle screw placement in posterior spinal fusion in children using intraoperative computed tomography (CT) navigation versus intraoperative fluoroscopy (C-arm). METHODS: In this review of posterior spinal fusion patients, height, weight, local density function, dose area product, body region, number of views, and part of the body were used to calculate the effective dose to the patient in millisieverts (mSv) in 37 children in whom pedicle screw placement was aided by intraoperative CT versus 44 children in whom pedicle screw placement was aided by C-arm. Both groups had posterior spinal fusions during the same time period by 3 surgeons between November 2012 and August 2013. Calculation of the radiation dose was made by the following method: for the C-arm, and the fluoroscopic/digital acquisitions part of the CT examinations, we estimated the effective dose using the program PCXMC 2.0. For the cross-sectional imaging part of the CT examinations, we used the dose-length product from the radiation dose reports of the CT unit and published dose-length product to effective dose conversion factors. The overall effective dose for the CT group was the total of the cross-sectional imaging dose and the fluoroscopic/digital acquisition imaging dose. An unpaired T test was used to determine significant difference between the C-arm and CT navigation groups. RESULTS: The average effective dose was 1.48±1.66 mSv for the CT patients and 0.34±0.36 mSv for the C-arm patients. These values for the 2 groups are significantly different (P=0.0012). Obese children had very high mSv values in the CT group. CONCLUSIONS: Intraoperative CT for navigational instrumentation placement associated with spinal fusion in children results in significantly more radiation to the child than C-arm. Families need to be counseled about radiation exposure associated with intraoperative CT, especially in obese children. Intraoperative CT use should be tailored to placing instrumentation where the benefit is the highest. LEVEL OF EVIDENCE: Level II.

Vitamin D Deficiency in Children Undergoing Vertical Expandable Prosthetic Titanium Rib Treatment.

BACKGROUND: Vitamin D deficiency is prevalent in the pediatric population and multiple risk factors have been identified. Low vitamin D levels can result in poor bone mineralization and have been associated with a significantly higher risk of forearm fracture in children. Vitamin D deficiency has also been associated with pediatric critical illness. The purpose of this study was to determine whether children undergoing vertical expandable prosthetic titanium rib (VEPTR) treatment have low vitamin D levels. METHODS: Patients undergoing VEPTR treatment at a single institution were prospectively enrolled (VEPTR). All patients either had a diagnosis of thoracic insufficiency syndrome (TIS), or were at risk of developing TIS secondary to progressive scoliosis or chest wall deformity. Exclusion criteria were patients with rickets and patients receiving vitamin D supplementation at the time of VEPTR insertion. A group of healthy children who presented with fractures during the winter season were used as controls (FX). Vitamin D status and risk factors for vitamin D deficiency were evaluated. Vitamin D deficiency was defined as serum 25-hydroxyvitamin D (25-OH-D) <20 ng/mL and vitamin D insufficiency as serum 25-OH-D between 20 and 29 ng/mL. RESULTS: Twenty-eight VEPTR and 25 FX patients were compared. The average age was 8.6 years in the VEPTR group and 9.1 years in the FX group. Twenty VEPTR patients (71%) and 19 FX patients (76%) demonstrated low vitamin D levels. The average 25-OH-D level was 27.3 ng/mL in the VEPTR group and 25.4 ng/mL in the FX group. Patient characteristics and vitamin D levels were similar between the groups. No association was found between vitamin D status and sex, race, obesity, or multivitamin use. CONCLUSIONS: Low vitamin D levels are common in children undergoing VEPTR treatment. In our series, the prevalence of vitamin D deficiency in this patient population was similar to reported rates in the general pediatric population. Vitamin D status should be routinely monitored in children undergoing VEPTR treatment and supplementation should be initiated if necessary.

Osteochondromas after radiation for pediatric malignancies: a role for expanded counseling for skeletal side effects.

BACKGROUND: A relationship has been reported between total body irradiation (TBI) and later development of osteochondromas in children who receive radiation therapy as conditioning before hematopoietic stem cell transplantation (HSCT). The goal of this study was to better characterize osteochondromas occurring in these children. METHODS: We identified all children (0 to 18 y) who received an allogeneic HSCT and TBI from 2000 to 2012 from a blood and marrow transplant (BMT) database. Thereafter, we identified those who developed osteochondromas through a chart review. In addition, we searched for diagnosis and operative codes from 1996 to 2012 in our pediatric orthopaedic clinical records, isolating osteochondroma patients with a history of radiation exposure. RESULTS: Four patients who underwent allogeneic HSCT and were later diagnosed with osteochondromas were identified from the BMT database (N=233 children); all 4 were among a group of 72 patients who received TBI. Three patients were identified from orthopaedic records. The cohort included 5 boys and 2 girls with acute lymphoblastic leukemia (N=5) or neuroblastoma (N=2), diagnosed at a median age of 2.0 years. Therapy for all patients included chemotherapy, radiation therapy (TBI, N=5; abdominal, N=2), and HSCT. A diagnosis of osteochondroma was made at a median age of 11.7 years (range, 5 to 16 y), on average 8.6 years after radiation therapy. Diagnosis was incidental in 2 patients and secondary to symptoms (pain or genu valgum) in 5. Locations of osteochondromas were the proximal tibia (N=3), distal tibia, distal femur, distal ulna, and the distal phalanx (N=1 each). Three patients underwent surgical resection. CONCLUSIONS: Children may be more likely to develop osteochondromas after early exposure to radiation therapy, which may cause pain and require surgical resection. To the best of our knowledge, this is the first reported case of a radiation-induced osteochondroma causing lower extremity malalignment. Patients typically present to the pediatric orthopaedist's attention when symptomatic, but there may be an expanded role for counseling for potential for long-term skeletal effects in this group. LEVEL OF EVIDENCE: Level IV, case series.

Congenital scoliosis SRS-22 outcomes in children treated with observation, surgery, and VEPTR.

STUDY DESIGN: Prospective, nonrandomized study of children with congenital scoliosis. OBJECTIVE: To determine the outcomes of children with congenital scoliosis using SRS-22. SUMMARY OF BACKGROUND DATA: Outcome measures in children with congenital scoliosis are unreported. Novel treatments such as VEPTR (vertical expandable prosthetic titanium rib) must show positive patient-reported outcomes during treatment because improvement in pulmonary function has not been demonstrated. METHODS: Patients with congenital scoliosis were prospectively enrolled and divided into 3 groups: children under observation (OBSERVATION), children who had surgery (SURGICAL), and children treated with VEPTR (VEPTR). The SRS-22 questionnaire reports 6 domains: Total, Function, Mental Health, Image, Satisfaction, and Pain. SRS-22 questionnaires were prospectively collected from 184 OBSERVATION patients, 27 SURGICAL patients, and 22 VEPTR patients. Because of repeated measurement on each patient, the observations cannot be assumed to be independent. To account for this dependence, linear mixed models were used. RESULTS: OBSERVATION scores were near normal in all domains. Initial postoperative scores for Function and Pain decreased for the SURGICAL group and subsequently Total, Function, Image, and Satisfaction scores increased. Initial postoperative VEPTR scores in Mental Health and Pain decreased and Total, Function, and Image scores increased during subsequent visits. CONCLUSION: Children with congenital scoliosis had SRS-22 scores that compare favorably with scores reported in the literature for adolescent idiopathic scoliosis. For SURGICAL and VEPTR patients with congenital scoliosis, SRS-22 Total, Function, and Image scores increased over time. Function, Image, and Pain require focus in children with congenital scoliosis. This is the first study that documents improvement in outcomes of VEPTR patients while in treatment. LEVEL OF EVIDENCE: 2.