Chan Hee Jo

The clinical usefulness of polymerase chain reaction as a supplemental diagnostic tool in the evaluation and the treatment of children with septic arthritis

Introduction: Culture-negative septic arthritis occurs frequently in children. The supplemental use of polymerase chain reaction (PCR) techniques improves the detection of bacteria in the joint fluid. This study evaluates the clinical utility of PCR at a tertiary pediatric medical center. Methods: Children with septic arthritis were studied prospectively from 2012 to 2014. Culture results and clinical infection parameters were recorded. PCR was performed whenever sufficient fluid was available from the joint aspiration. A statistical comparison was made for the rates of identification of the causative organism by these methods. A subgroup analysis was performed to assess the correspondence of clinical and laboratory parameters with the results of joint fluid culture and PCR. Results: Ninety-nine children with septic arthritis were enrolled consecutively. A broad range of parameter results was identified among these children with an average of 3.6 of 6 parameters per child that met thresholds of infection. Joint fluid cultures were positive in 34 of 97 (35.1%) children from whom they were sent. Among the 68 children from whom the material was sent for PCR, the result was positive in 32 (47.1%). The combination of blood culture, joint fluid culture, and PCR resulted in bacterial detection in 49 of 97 (50.5%) children. PCR improved the rate of detection of Kingella kingae markedly when compared with joint fluid culture. PCR results were available at an average of 14.6 days after the acquisition of joint fluid. 16S PCR results were reported at an average of 17.5 days, whereas Kingella PCR took 5.1 days. Discussion: PCR provides supplemental information for diagnostic confirmation through an increased rate of detection of bacteria. The timing of results and the inability to provide antibiotic sensitivity are factors that limit its clinical usefulness currently. Level of Evidence: Level II—diagnostic study (consecutive patients with universally applied reference gold standard).

Lengthening in Congenital Femoral Deficiency: A Comparison of Circular External Fixation and a Motorized Intramedullary Nail.

BACKGROUND Circular external fixation for limb-lengthening is associated with frequent and numerous complications. Intramedullary lengthening devices represent a potential advance in limb-lengthening. The purpose of this study was to compare the outcomes of femoral lengthening in pediatric patients treated by either circular external fixation or a motorized intramedullary nail. METHODS All patients with a diagnosis of congenital femoral deficiency who had undergone femoral lengthening with either circular external fixation or a motorized intramedullary nail were identified. The motorized intramedullary nail (FITBONE) was used with approval of the U.S. Food and Drug Administration on an individual compassionate-use basis. RESULTS Fourteen skeletally mature patients underwent fourteen femoral lengthening sessions using circular external fixation, and thirteen patients underwent fifteen lengthening sessions using the motorized nail. The amount lengthened was similar, with a mean of 4.8 cm (range, 1.0 to 7.4 cm) in the circular fixation group and 4.4 cm (range, 1.5 to 7.0 cm) in the motorized nail group. Complications occurred in all lengthening sessions in all fourteen patients managed with the circular external fixation and in 73% of fifteen lengthening sessions in the thirteen patients managed with the motorized nail. The circular external fixation group averaged 2.36 complications per lengthening session compared with 1.2 per session in the motorized nail group. Twenty-nine percent of the circular fixation group failed to achieve a lengthening goal of at least 4 cm compared with 27% of the motorized nail group who failed to reach the goal. Eight patients had undergone eleven femoral lengthening sessions with circular external fixation prior to undergoing ten lengthening sessions by motorized nail. These patients had a comparable rate of complications with both types of lengthening, but the total number of complications averaged 2.6 per lengthening session with circular external fixation compared with 1.6 per lengthening session with the motorized nail. CONCLUSIONS A decreased number of complications was noted with use of a motorized intramedullary nail compared with circular external fixation in pediatric patients undergoing femoral lengthening for congenital femoral deficiency. LEVEL OF EVIDENCE Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Microbiological culture methods for pediatric musculoskeletal infection: a guideline for optimal use.

BACKGROUND Culture results affect the diagnosis and treatment of children with musculoskeletal infection. To our knowledge, no previous large-scale study has assessed the relative value of culture methods employed during the evaluation of these conditions. The purpose of this study was to identify an optimal culture strategy for pediatric musculoskeletal infection. METHODS Children with musculoskeletal infection were retrospectively studied to assess culture results from the infection site or blood; culture type, including aerobic, anaerobic, fungal, and acid-fast bacteria (AFB); antibiotic exposure history; and clinical history of children with positive culture results. RESULTS We studied 869 children, including 353 with osteomyelitis, 199 with septic arthritis, forty-two with pyomyositis, and 275 with abscess. The 4537 cultures processed included 1303 aerobic, 903 anaerobic, 340 fungal, 289 AFB, and 1702 blood. Of 3004 specimens sent during initial work-up, positive results occurred in 677 of 1049 aerobic cultures (64.5%), 140 of 763 blood cultures (18.3%), eighteen of 722 anaerobic cultures (2.5%), five of 251 fungal cultures (2.0%), and two of 219 AFB cultures (0.9%). Staphylococcus aureus was the most common pathogen isolated, from 428 (50.7%) of 844 children for whom blood or infection-site culture material was sent (methicillin-resistant S. aureus, 252; and oxacillin-sensitive S. aureus, 176). Cultures were negative in 206 (29.0%) of the 710 children for whom culture material from the site of infection was sent. Children with true-positive anaerobic, fungal, or AFB cultures had a history of immunocompromise, penetrating inoculation, or failed primary treatment. Antibiotic exposure prior to culture-sample acquisition did not interfere with aerobic culture results from the site of infection. CONCLUSIONS Our findings suggest that anaerobic, fungal, and AFB cultures should not be routinely performed during the initial evaluation of children with hematogenous musculoskeletal infection. These cultures should be performed for children with immunocompromise, clinical suspicion of penetrating inoculation, or failed primary treatment.

Interobserver and intraobserver reliability of the modified waldenström classification system for staging of legg-calvé-perthes disease

BACKGROUND The absence of a reliable classification system for Legg-Calvé-Perthes disease has contributed to difficulty in establishing consistent management strategies and in interpreting outcome studies. The purpose of this study was to assess interobserver and intraobserver reliability of the modified Waldenström classification system among a large and diverse group of pediatric orthopaedic surgeons. METHODS Twenty surgeons independently completed the first two rounds of staging: two assessments of forty deidentified radiographs of patients with Legg-Calvé-Perthes disease in various stages. Ten of the twenty surgeons completed another two rounds of staging after the addition of a second pair of radiographs in sequence. Kappa values were calculated within and between each of the rounds. RESULTS Interobserver kappa values for the classification for surveys 1, 2, 3, and 4 were 0.81, 0.82, 0.76, and 0.80, respectively (with 0.61 to 0.80 considered substantial agreement and 0.81 to 1.0, nearly perfect agreement). Intraobserver agreement for the classification was an average of 0.88 (range, 0.77 to 0.96) between surveys 1 and 2 and an average of 0.87 (range, 0.81 to 0.94) between surveys 3 and 4. CONCLUSIONS The modified Waldenström classification system for staging of Legg-Calvé-Perthes disease demonstrated substantial to almost perfect agreement between and within observers across multiple rounds of study. In doing so, the results of this study provide a foundation for future validation studies, in which the classification stage will be associated with clinical outcomes.

The Effect of the Risser Stage on Bracing Outcome in Adolescent Idiopathic Scoliosis

BACKGROUND To determine the influence of the Risser sign on the need for surgery in children wearing orthoses for the treatment of adolescent idiopathic scoliosis (AIS), data on compliance with brace wear were collected and analyzed. METHODS One hundred and sixty-eight patients were prospectively enrolled at the time that brace wear had been prescribed and were followed until the cessation of bracing or the need for surgery. Inclusion criteria were a curve magnitude between 25° and 45°; a Risser stage of 0, 1, or 2; and, if female, <1 year post menarche at the time of brace prescription. Compliance was measured using thermal monitors. RESULTS The prevalence of surgery, or progression to a curve magnitude of ≥50°, was 44.2% for patients at Risser stage 0 (n = 120), 6.9% for patients at Risser stage 1 (n = 29), and 0% for patients at Risser stage 2 (n = 19). Brace wear averaged 11.3, 13.4, and 14.2 hours per day for the Risser stage-0, 1, and 2 groups, respectively. While the groups had no difference in initial curve magnitude (p = 0.11), more patients at Risser stage 0 had progression to surgery than did patients at Risser stage 1 or stage 2 despite bracing (p < 0.0001). Twenty-six (41.9%) of 62 Risser stage-0 patients who wore braces ≥12.9 hours per day had progression to surgery. Ten patients at Risser stage 0 with closed triradiate cartilage wore braces ≥18 hours per day, and none underwent surgery. In comparison, 7 of 10 patients at Risser stage 0 with open triradiate cartilage and similar daily brace wear underwent surgery. Of 9 patients at Risser stage 0 with open triradiate cartilage who wore braces ≥12.9 hours daily for curves measuring <30°, 7 had a nonsurgical outcome. CONCLUSIONS Patients at Risser stage 0 are at risk for surgery despite brace wear. In these patients, 12.9 hours of daily wear-the number of hours linked with a successful outcome in the BRAIST (Bracing in Adolescent Idiopathic Scoliosis Trial)-did not prevent surgery. Patients with open triradiate cartilage were at highest risk, especially those with curves of ≥30°. Risser stage-0 patients should be prescribed a minimum of 18 hours of brace wear. Bracing should be initiated for curves of <30° in patients at Risser stage 0, especially those with open triradiate cartilage. LEVEL OF EVIDENCE Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Patient-Reported Health Outcomes After in Situ Percutaneous Fixation for Slipped Capital Femoral Epiphysis: An Average Twenty-Year Follow-up Study

BACKGROUND Percutaneous in situ fixation is the gold-standard treatment for stable slipped capital femoral epiphysis (SCFE). While numerous studies have documented good to excellent long-term clinical and radiographic outcomes, few have documented long-term patient-reported outcomes of patients with this condition. METHODS This retrospective study was performed to document long-term patient-reported outcomes of a cohort of sixty-four patients with SCFE (ninety-one affected hips) and determine whether the slip angle was associated with poorer health outcomes as measured with the Short Form-12 (SF-12) Physical Component Summary (PCS) and Mental Component Summary (MCS) scores, modified Harris hip score (mHHS), and University of California at Los Angeles (UCLA) Activity Scale. RESULTS The mean age at presentation was 12.6 years, and the mean duration of follow-up was 19.6 years. At the time of follow-up, the cohort reported higher rates of diabetes, obesity, and hypertension than the general U.S. POPULATION The mean body mass index (BMI) had increased by 10.2 kg/m(2), with 72% of the subjects meeting the criteria for obesity (BMI > 30 kg/m(2)) at the time of follow-up. The mean age and sex-adjusted PCS and MCS scores were 49.6 and 50.0, respectively, and the mean mHHS was 84.9. Multivariable general linear modeling revealed no association between the initial slip angle and the PCS, MCS, mHHS, or UCLA Activity Scale score. Male sex and a lower BMI were the only predictors of better long-term PCS, mHHS, and UCLA Activity Scale scores. Subjects with a bilateral slip had outcomes similar to those with unilateral disease. CONCLUSIONS The general self-reported health of this cohort was poor compared with that of the general population. The slip angle on presentation did not correlate with any patient-reported outcome measure collected for this study. Higher BMI was one of the only clinical predictors of patient-reported outcomes.

Brace Success Is Related to Curve Type in Patients with Adolescent Idiopathic Scoliosis.

Background: Curve magnitude and skeletal maturity are important factors in determining the efficacy of bracing for the treatment of adolescent idiopathic scoliosis, but curve morphology may also affect brace success. The purpose of this study was to determine the influence of curve morphology on the response to bracing with a thoracolumbosacral orthosis (TLSO). Methods: A retrospective review of patients managed with an orthosis for the treatment of adolescent idiopathic scoliosis who were prospectively enrolled at the initiation of brace wear and followed through completion of bracing or surgery was performed. Inclusion criteria were main curves of 25° to 45° and a Risser stage of 0, 1, or 2 at the time of brace prescription. Compliance with bracing was measured with Maxim Integrated Thermochrons. Radiographs made at brace initiation, brace cessation, and final follow-up were used to retrospectively categorize curves with use of the modified Lenke (mLenke) classification system and more broadly to categorize them as main thoracic or main lumbar. The effect of morphology on outcome was evaluated using chi-square and Fisher exact tests. Results: One hundred and sixty-eight patients were included. There was no difference in curve magnitude at the time of brace initiation (p = 0.798) or in average hours of daily brace wear (p = 0.146) between groups. The rate of surgery or progression of the curve to ≥50° was 34.5% (29 of 84) in mLenke-I curves, 54.5% (6 of 11) in mLenke-II curves, 29.4% (10 of 34) in mLenke-III curves, 17.6% (3 of 17) in mLenke-V curves, and 13.6% (3 of 22) in mLenke-VI curves. There were no mLenke-IV curves at the time of brace initiation. The rate of surgery or progression to ≥50° was 34.1% (44 of 129) in the combined thoracic group and 15.4% (6 of 39) in the combined lumbar group (p = 0.0277). In brace-compliant patients (>12.9 hours/day), the rate of surgery or progression to ≥50° was 30.3% (20 of 66) in main thoracic curves and 5.3% (1 of 19) in main lumbar curves (p = 0.0239). One-tenth of curves changed morphology during bracing. The rate of surgery or progression to ≥50° was 35.8% (43 of 120) in persistent main thoracic curves, 20.0% (6 of 30) in persistent main lumbar curves, 12.5% (1 of 8) in main thoracic curves that became main lumbar curves, and 0% (0 of 9) in main lumbar curves that became main thoracic curves (p = 0.0383). Conclusions: Thoracic curves are at greater risk for brace failure than lumbar curves are despite similar initial curve magnitudes and average amount of daily brace wear. A change in curve pattern may imply flexibility and is associated with brace success. Patients with thoracic curves should be counseled accordingly. Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Sequential Parenteral to Oral Clindamycin Dosing in Pediatric Musculoskeletal Infection: A Retrospective Review of 30 mg/kg/d Versus 40 mg/kg/d

Background: Children with musculoskeletal infection in methicillin-resistant Staphylococcus aureus (MRSA) prevalent communities are often treated with oral clindamycin. Current guidelines recommend approximately 40 mg/kg/d for MRSA infections. This study investigates the clinical practice of using 30 mg/kg/d of clindamycin as an alternative for outpatient dosing. Methods: Children with musculoskeletal infection treated with outpatient clindamycin from 2009 to 2014 were studied by retrospective review. The amount of clindamycin administered was determined from dose, interval and duration of outpatient treatment. Hospital readmission, surgeries and sequelae were assessed. Severity of illness was determined for children with osteomyelitis. The readmission rate of 25 children treated with 40 mg/kg/d was compared with that of 190 children treated with 30 mg/kg/d. The reason for readmission was evaluated to consider whether antibiotic dosing strategy was a potential factor. Results: Among 215 children studied, the average outpatient duration of treatment was 32.8 days. There was no significant difference in the rate of readmission between dosing cohorts. Severity of illness scores (0–10 scale) was significantly higher among readmitted children with osteomyelitis (mean 9.8 ± 0.4) than among those with osteomyelitis who were not readmitted (mean 2.9 ± 3.2), P = 0.001. Sequelae were more common in the high-dose group and were noted in 3 children (12%) in that cohort compared with 6 children (3.2%) in the low-dose cohort (P > 0.05). Conclusion: Oral dosing of 30 mg/kg/d was effective for musculoskeletal infection in children in an MRSA prevalent community. Illness severity appeared to have greater impact on readmission and sequelae than did antibiotic dosing.

A Longitudinal Review of Gait Following Treatment for Idiopathic Clubfoot: Gait Analysis at 2 and 5 Years of Age.

Background: Initial correction following nonoperative (NonOp) treatment for idiopathic clubfoot has been reported in 95% of feet by age 2; however, by age 4, approximately one third of feet undergo surgery due to relapse. The purpose of this study was to assess the longitudinal effect of growth and surgical (Sx) intervention on gait following NonOp and Sx treatment for clubfoot. Methods: Children with idiopathic clubfoot were seen for gait analysis at 2 and 5 years of age. Kinematic data were collected at both visits, and kinetic data were collected at age 5 years. Group comparisons were made between feet treated with the Ponseti casting technique (Ponseti) and the French physical therapy method (PT) and between feet treated nonoperatively and surgically. Comparisons were made between feet treated with a limited release or tendon transfer (fair) and those treated with a full posteromedial release (poor). The &agr; was set to 0.05 for all statistical analyses. Results: Gait data from 181 children with 276 idiopathic clubfeet were collected at both age 2 and 5 years. Each foot was initially treated with either the Ponseti (n=132) or PT (n=144) method but by the 5-year visit, 30 Ponseti and 61 PT feet required surgery. Gait outcomes showed limitations primarily in the Sx clubfeet. Normal ankle motion was only present in 17% of Ponseti and 21% of PT feet by age 5 following Sx management. Sx PT feet showed persistent intoeing at age 2 and 5. Within the Sx group, feet initially treated with PT had a clinically significant reduction in ankle power compared with those treated initially by the Ponseti method. Feet treated with posteromedial releases had significantly less ankle power than those treated with limited surgery or that remained NonOp at 5 years. Conclusions: This longitudinal study shows subtle changes between 2 and 5 years, and continues to support a NonOp approach in the treatment of clubfoot. Level of Evidence: Level II—therapeutic.

Improved Magnetic Resonance Imaging Utilization for Children with Musculoskeletal Infection

BACKGROUND Magnetic resonance imaging (MRI) with sedation is an important resource used to evaluate children with musculoskeletal infection. This study assesses the impact of multidisciplinary guidelines and continuous process improvement on MRI utilization at a tertiary pediatric medical center. METHODS A multidisciplinary team developed a guideline for MRI with sedation, and it was implemented at our institution. Scan duration, anatomic regions imaged, sequences performed, timing of surgical intervention, length of hospital stay, and readmissions for these children were compared with these measures among a cohort of similar children who had been treated prior to guideline implementation. Comparative data were gathered for the subsequent cohort to determine any impact of the continued process improvement program on MRI utilization. Statistical comparison was performed to determine significant differences between groups. RESULTS Children evaluated prior to the guideline implementation had 9.0 MRI sequences per scan, an MRI scan duration of 111.6 minutes, and a hospital stay of 7.5 days. In comparison, children in the initial MRI guideline cohort had 7.5 sequences per scan, a scan duration of 76.1 minutes, and a hospital stay of 5.4 days. Children in the subsequent guideline cohort had 6.5 sequences per scan, a scan duration of 56.3 minutes, and a hospital stay of 5.0 days. The rate of immediate surgical procedure under continued anesthesia was 16.7% prior to the guideline, 50.5% among children in the initial guideline cohort, and 64% among children in the subsequent guideline cohort. Differences between cohorts were significant (p < 0.0001). In aggregate, 264 hours of MRI scan time and 809 hospital bed-days were conserved for more than thirty months. CONCLUSIONS This initiative promoted improvement in diagnostic efficiency, therapeutic consistency, and patient safety for children with musculoskeletal infection. CLINICAL RELEVANCE The findings of this study illustrate the beneficial impact of interdisciplinary coordination of care on clinical outcomes for children with musculoskeletal infection. Tangible improvements occurred for both length of stay and resource utilization.