Retrospective validation of a rapid Lyme fluorescent immunoassay in differentiating Lyme arthritis from other musculoskeletal presentations in children in a Lyme-endemic region.

Lyme arthritis can present similarly to other causes of joint pain and swelling including septic arthritis and other acute and chronic arthropathies of childhood. Septic arthritis, although rare, constitutes an orthopedic emergency and requires early surgical intervention to reduce the risk of permanent joint damage. Currently, results of standard serologic tests to diagnose Lyme disease take days to weeks, which is unhelpful in acute clinical decision-making. Thus, some children with Lyme arthritis are treated empirically for septic arthritis undergoing unnecessary invasive procedures and hospital admission while on inappropriate antibiotic therapy. We retrospectively validated the Quidel Sofia Lyme Fluorescent Immunoassay, a rapid serologic assay that can detect IgG and/or IgM antibodies to Borrelia burgdorferi in 10 minutes, in residual serum samples collected from 51 children who had Lyme arthritis and 55 children with musculoskeletal presentations who were Lyme negative. The sensitivity and specificity of the Sofia IgG to identify cases of Lyme arthritis in children were 100% (95% confidence interval [CI] of 93.0%-100%) and 96.4% (95% CI: 87.5%-99.6%), respectively. The positive likelihood ratio (LR) was 27.5 (95% CI 7-107), and the negative LR was 0.00 (95% LR 0.00-0.15). We propose that the Sofia IgG, a rapid method for identifying Lyme arthritis, may be useful in differentiating Lyme arthritis from other forms of arthritis. Used in conjunction with readily available clinical and laboratory variables, it could help to rapidly identify children who are at low risk of septic arthritis in Lyme-endemic regions. IMPORTANCE: Lyme arthritis is a common manifestation of Lyme disease in children, with clinical features overlapping with other causes of acute and chronic joint pain/swelling in children. We have demonstrated that the Sofia IgG is a reliable test to rule in and rule out the diagnosis of Lyme arthritis in children with musculoskeletal presentations in a Lyme-endemic region. When used in conjunction with clinical and laboratory variables routinely considered when differentiating Lyme arthritis from other diagnoses, the Sofia IgG has the potential to fill an important gap in care, especially when acute decision-making is necessary. The Sofia IgG should be included in prospective research studies examining clinical prediction tools to identify children at low risk of septic arthritis.

Are 2 Radiographic Views As Good as 3 Views to Diagnose Ankle Fractures in Children and Adolescents?

OBJECTIVES: Ankle radiographs are among the most commonly obtained trauma images in the pediatric population, with the standard 3 views (AP/mortise [M]/lateral [L]) routinely ordered in the emergency department. The purpose of this study was to compare the diagnostic accuracy, sensitivity, and specificity of sets of 2 views (AP/L or M/L) with the standard 3 views. METHODS: One hundred twenty sets of ankle radiographs of skeletally immature patients obtained in the emergency department of a level 1 pediatric trauma center were used. These included sets with and without fractures. Sets of 3 and 2 views were reviewed by pairs of pediatric-trained orthopedic surgeons, radiologists, and emergency physicians. Each completed 3 randomized viewing sessions where all possible combinations for each set of radiographs were reviewed. Diagnoses for the 3 sets of views were compared for accuracy, sensitivity, and specificity. RESULTS: Overall accuracy, sensitivity, and specificity for all reviewers were as follows: AP/M/L 74%, 94%, and 90%, AP/L 71%, 90%, and 94%, as well as M/L 69%, 90%, and 91%. P values for accuracy, sensitivity, and specificity of AP/L and M/L compared with 3 views were 0.34, 0.04, and 0.52, as well as 0.04, 0.004, and 1.00, respectively. CONCLUSIONS: In skeletally immature patients, statistically significant differences in accuracy were obtained when comparing the standard 3 AP/M/L views with more limited M/L views, suggesting that this set of 2 views is not as accurate. Differences in sensitivity of limited views were also statistically significant. Conversely, differences in accuracy between the standard 3 views and AP/Lateral views were not statistically significant. While more limited AP/L views may be comparable in accuracy and specificity and lead to dramatically decreased radiation and costs, this can be at the expense of less diagnostic sensitivity and increased risk of misdiagnosing or missing certain fractures. LEVEL OF EVIDENCE: Level III.

Pediatric femoral shaft fractures secondary to tombstone uprooting - Two case reports.

CASE: Two cases are reported of femoral shaft fractures involving tombstones. A four and six year old child had similar histories of uprooting of tombstones during play, toppling them and causing injury. Treatment included non-operative and operative approaches, with both patients yielding bony union at the three month follow up. CONCLUSION: We present the involvement of tombstones as a unique mechanism of injury for femoral shaft fractures in two pediatric cases. From our review of the literature, we believe this to be a first report. We hope to highlight the associated safety implications for the primary prevention of a similar traumatic injury.

Femoral Neck Growth and Remodeling With Free-Gliding Screw Fixation of Slipped Capital Femoral Epiphysis.

BACKGROUND: Treatment of stable slipped capital femoral epiphysis (SCFE) most commonly involves in situ fixation with a standard cannulated screw, leading to physeal arrest. Recently, Pega Medical (Laval, Canada) introduced the free-gliding (FG) SCFE screw, which employs a growth-friendly, telescopic design. This study examines femoral neck growth and remodeling over the first 2 postoperative years in stable SCFE treated with FG versus standard screws. METHODS: We retrospectively reviewed 32 hips (19 SCFE, 13 prophylactic) in 16 patients treated with FG screws for stable SCFE. We also reviewed 102 hips (63 SCFE, 19 prophylactic, 20 controls) in 55 patients treated with standard screws. Immediate postoperative radiographs were compared with 1- and 2-year follow-up images. RESULTS: For the overall study cohort, mean age at surgery was 12.2±1.9 years, with a mean slip angle of 26.9±18.0 degrees. In FG SCFE hips, the alpha angle remodeled 12.9±19.2 degrees in the first postoperative year (P=0.018) and articulotrochanteric distance decreased by 4.2±4.6 mm at 2 years (P=0.018). In standard SCFE hips, the alpha angle remodeled 4.3±11.3 degrees at 1 year (P=0.014), while articulotrochanteric distance decreased by 4.5±3.2 mm at 2 years (P<0.001). By 2 years, FG screws lengthened more in prophylactic (4.8±3.4 mm) than SCFE hips (1.7±1.8 mm, P=0.027). CONCLUSIONS: Greater remodeling of femoral neck cam deformity occurs when treating SCFE using an FG screw. Further research is required to measure the impact of this finding on femoroacetabular impingement and degenerative arthritis. In addition, FG screws allow ongoing growth of prophylactically treated hips, while standard screws promote coxa breva. LEVEL OF EVIDENCE: Level III-retrospective comparative, therapeutic study.

Distraction-based surgeries increase thoracic sagittal spine length after ten lengthening surgeries for patients with idiopathic early-onset scoliosis.

STUDY DESIGN: Retrospective, comparative, multicenter. OBJECTIVES: To determine if the choice of proximal anchor affects thoracic sagittal spine length (SSL) for children with idiopathic early-onset scoliosis (EOS). Debate exists as to whether spine growth is maintained during treatment for EOS. As rib- (RB) and spine-based (SB) distraction procedures may be kyphogenic, the traditional measurement of spine growth on coronal radiographs may not identify out-of-plane increase in spine length. A measure of SSL, along the spine's sagittal arc of curvature, has been validated to reliably assess the length of the thoracic spine. METHODS: Patients with idiopathic EOS treated with distraction-based systems (minimum 5-year follow-up, five lengthening surgeries) with radiographic analysis preoperatively, postimplant (L1), and during lengthening periods (L2-L5, L6-L10) were evaluated with primary outcome of T1-T12 SSL. RESULTS: We identified 34 patients (14 RB, 20 SB) with preoperative age 4.9 years (4.2 RB vs. 5.4 SB), scoliosis 72° (60° RB vs. 77° SB; p < 0.05), kyphosis 39° (50° RB vs. 34° SB; p < 0.05), and SSL 17.8 cm (15.5 RB vs. 18.5 SB; p < 0.05). After initial scoliosis correction from implantation, scoliosis remained constant over time. RB patients had greater kyphosis than SB patients: L1, 46° RB vs. 19° SB (p < 0.05); L2-L5, 50° RB vs. 27° SB (p < 0.05); L6-L10, 56° RB vs. 26° SB (p < 0.05). SSL increased for both groups from preoperative to the tenth lengthening (p < 0.05). As compared with RB patients, SB patients had higher SSL preoperatively and maintained this difference to the tenth lengthening (p < 0.05). After ten lengthening surgeries, when normalized to preoperative SSL, relative thoracic growth was greater for RB (27%) than for SB patients (19%) (p < 0.05). CONCLUSION: Regardless of proximal anchor choice, thoracic length continued to increase during the distraction phase of treatment for idiopathic EOS. LEVEL OF EVIDENCE: Level III.

Relationship of muscle morphology to hip displacement in cerebral palsy: a pilot study investigating changes intrinsic to the sarcomere.

BACKGROUND: Cerebral palsy (CP) is the most common cause of childhood disability, typified by a static encephalopathy with peripheral musculoskeletal manifestations-most commonly related to spasticity-that are progressive with age. Hip displacement is one of the most common manifestations, observed to lead to painful degenerative arthritis over time. Despite the key role that spasticity-related adductor muscle contractures are thought to play in the development of hip displacement in CP, basic science research in this area to date has been limited. This study was initiated to correlate hip adductor muscle changes intrinsic to the sarcomere-specifically, titin isoforms and sarcomere length-to the severity of hip displacement in children with spastic cerebral palsy. METHODS: Single gracilis muscle biopsies were obtained from children with CP (Gross Motor Function Classification System (GMFCS) III-V; n = 10) who underwent adductor muscle release surgery for the treatment of hip displacement. Gel electrophoresis was used to estimate titin molecular weight. Sarcomere lengths were measured from muscle fascicles using laser diffraction. The severity of hip displacement was determined by measuring by Reimers migration percentage (MP) from anteroposterior pelvic x-rays. Correlation analyses between titin, sarcomere lengths, and MP were performed. RESULTS: The mean molecular weight of titin was 3588 kDa. The mean sarcomere length was 3.51 µm. Increased MP was found to be associated with heavier isoforms of titin (R2 = 0.65, p < 0.05) and with increased sarcomere lengths (R2 = 0.65, p < 0.05). Heavier isoforms of titin were also associated with increased sarcomere lengths (R2 = 0.80, p < 0.05). CONCLUSIONS: Our results suggest that both larger titin isoforms and sarcomere lengths are positively correlated with increased severity of hip displacement and may represent adaptations in response to concomitant increases in spasticity and muscle shortening. TRIAL REGISTRATION: As this study does not report the results of a health care intervention on human participants, it has not been registered.

Stiffness of hip adductor myofibrils is decreased in children with spastic cerebral palsy.

Cerebral palsy (CP) is the result of a static brain lesion which causes spasticity and muscle contracture. The source of the increased passive stiffness in patients is not understood and while whole muscle down to single muscle fibres have been investigated, the smallest functional unit of muscle (the sarcomere) has not been. Muscle biopsies (adductor longus and gracilis) from pediatric patients were obtained (CP n = 9 and control n = 2) and analyzed for mechanical stiffness, in-vivo sarcomere length and titin isoforms. Adductor longus muscle was the focus of this study and the results for sarcomere length showed a significant increase in length for CP (3.6 µm) compared to controls (2.6 µm). Passive stress at the same sarcomere length for CP compared to control was significantly lower in CP and the elastic modulus for the physiological range of muscle was lower in CP compared to control (98.2 kPa and 166.1 kPa, respectively). Our results show that CP muscle at its most reduced level (the myofibril) is more compliant compared to normal, which is completely opposite to what is observed at higher structural levels (single fibres, muscle fibre bundles and whole muscle). It is noteworthy that at the in vivo sarcomere length in CP, the passive forces are greater than normal, purely as a functional of these more compliant sarcomeres operating at long lengths. Titin isoforms were not different between CP and non-CP adductor longus but titin:nebulin was reduced in CP muscle, which may be due to titin loss or an over-expression of nebulin in CP muscles.

Guided growth for angular correction in children: a comparison of two tension band plate designs.

This retrospective cohort study examined 20 patients (48 physes), 11 boys and nine girls, who were treated with hinge-plate or eight-plate. The mean age of the patients at surgery was 11.9±2.6 years. The mean follow-up duration was 13±2.7 months. The radiographic measurement of both distal femoral and proximal tibial deformity showed significant correction, with no difference between the hinge-plate and the eight-plate. Both screw divergence angle and the hinge angle showed significant changes at the last follow-up. The deformity correction of the distal femoral physis was quicker than the proximal tibial physis. The rate of mechanical femoral-tibial angle correction was 0.97°/month if both femoral and tibial physes were treated. LEVEL OF EVIDENCE: III.

Three-dimensional True Spine Length: A Novel Technique for Assessing the Outcomes of Scoliosis Surgery.

BACKGROUND: Current assessment of spine growth for patients undergoing growth friendly surgical treatment for early-onset scoliosis (EOS) is the use of serial, 1-dimensional standard-of-care coronal vertical spine height (SoCVH) measurements. Any growth of the spine out of the coronal plane is missed by the SoCVH, which may underestimate the actual growth of the spine. This study set to validate the novel 3-dimensional true spine length (3DTSL) radiographic measurement technique for measuring growth of EOS patients. METHODS: 3DTSL measurement accuracy, reliability, and repeatability was assessed using 10 physical model configurations. In addition, interrater and intrarater reliabilities (IRRs) were assessed using interclass coefficient (ICC) analyses of 23 retrospective EOS patient clinical radiographs. 3DTSL measurements were compared with SoCVH measurements. RESULTS: The model assessment showed excellent accuracy with a mean error of 1.2 mm (SD=0.9; range, 0.0 to 3.0) and mean ICC of 0.999.IRR ICCs of the clinical radiographs averaged 0.952 for the 3DTSL and 0.975 for the vertical height whereas IRRs averaged 0.944 and 0.965, respectively (all P<0.001).Mean clinical 3DTSL curve lengths were 193.9 mm (SD=30.0; range, 142.8 to 276.8), whereas the SoCVH averaged 156.1 mm (SD=29.7; range, 74.7 to 207.3). The mean difference between the matched 3DTSL and SoCVH measurements was 37.8 mm (SD=21.4; range, 1.3 to 95.4) and was statistically significant (P<0.0001). On average, the 3DTSL of the measured spines was 124.2% of the measured SoCVH, with a progressive difference as the Cobb or kyphosis angles increased. CONCLUSIONS: The novel 3DTSL measurement is accurate, repeatable, and complements the current growth assessments for EOS treatments. LEVEL OF EVIDENCE: Level II-diagnostic study-development of a diagnostic criteria on basis of consecutive patients, with gold standard.

The 'trampoline ankle': severe medial malleolar physeal injuries in children and adolescents secondary to multioccupant use of trampolines.

The purpose of this study was to describe a series of patients presenting with medial malleolus Salter-Harris types III and IV fractures (MacFarland fractures) related to trampoline use. In total, 11 patients were reviewed retrospectively (mean age: 11.8 years; four boys and seven girls). Salter-Harris type III fractures were more commonly seen (n=7). Undisplaced fractures were more prevalent (n=6). Six children underwent surgical treatment. Average follow-up time was 17.8 months. A medial physeal bar with subsequent growth arrest and ankle deformity was observed in two patients. More than one user was present on the trampoline at the time of the injury in nine of the reported cases. Medial malleolus growth-plate injuries can be seen after trampoline injuries where multiple users were involved. Potential complications including growth arrest can occur.

Reliability of Proximal Junctional Kyphosis Measurements for Young Children With Scoliosis.

DESIGN: Retrospective comparison. OBJECTIVES: To determine whether the choice of proximal junctional kyphosis (PJK) definition affects reported rates and reliability of measurement of PJK for the same group of children treated with growth-friendly surgery. BACKGROUND: Distraction-based surgery has been associated with the development of PJK, which may lead to premature implant failure and may affect the upper instrumented level. Proximal junctional kyphosis has not been clearly defined in the literature and recent studies have used various definitions, resulting in widely varying rates of PJK. As a first step toward defining risk factors that may lead to clinically significant PJK, an evaluation of definitions of PJK should be performed. METHODS: The researchers analyzed radiographs of 36 children who were treated with growth-friendly surgery. The rates of PJK were determined using 3 recently described definitions. Five observers each measured the radiographs 2 weeks apart. Reliability was measured using the kappa statistic and intraclass correlation. RESULTS: At 2-year follow-up, rates of PJK varied between 6% and 42% depending on the definition used. Interobserver agreement for PJK at time 1 yielded fair agreement for definition 1 (κ = 0.31), moderate for definition 2 (κ = 0.40), and fair for definition 3 (κ = 0.38). Interobserver agreement for junctional angle at time 1 was fair (intraclass correlation coefficient [ICC], 0.48) for definition 1, good (ICC, 0.71) for definition 2, and fair (ICC, 0.55) for definition 3. Intra-observer agreement between times 1 and 2 for junctional angle was good (ICC, 0.61) for definition 1, excellent (ICC, 0.82) for Definition 2, and good (ICC, 0.69) for definition 3. CONCLUSIONS: When assessed with the same group of children, rates of PJK varied depending on the definition used. Interobserver reliability was fair to moderate; however, better interobserver and intra-observer agreement were noted with definition 2.

Perioperative Neurologic Injury Associated With Rib-Based Distraction Surgery.

STUDY DESIGN: Retrospective, comparative case series from the study group database. OBJECTIVES: The primary objective was to report the neurologic injury rate for rib-based distraction surgery and determine whether preoperative diagnosis affects this rate. The secondary objective was to describe these injuries and outcome. SUMMARY OF BACKGROUND DATA: Posterior distraction-based systems are commonly used to treat early-onset scoliosis. General complication rates for these surgeries are high; however, there are few reports in the literature on neurologic injury after rib-based distraction surgery. METHODS: This was a retrospective review of the Children's Spine Study Group database from 2004 to 2013. The researchers used the chi-square test to compare the distributions of proportions between diagnoses. RESULTS: A total of 524 patients were identified and treated with rib-based distraction surgery. The preoperative diagnoses consisted of 222 congenital/structural, 163 neuromuscular, 63 syndromic, 67 idiopathic, and 9 unknown. There were 9 neurologic injuries (7 clinical and 2 neuromonitoring alerts) for a neurologic injury rate of 1.7%. Using the Classification for Early-Onset Scoliosis, 8 patients were classified as congenital and 1 as neuromuscular. The neurologic injury rate in the congenital curves group was 3.6% and was 0.34% in non-congenital curves (p = .005). The proportion of injured patients with an additional secondary diagnosis was 3.82%, compared with 0.82% patients with only a primary diagnosis (p = .01). Eight injuries occurred at initial implantation and 1 at revision surgery. Most were brachial plexus (n = 5) with no complete spinal cord injuries. Four patients required return to surgery and 1 needed intraoperative intervention. At 4.2 years' follow-up, 7 of 9 patients had full resolution of symptoms and 2 patients had residual upper extremity weakness. CONCLUSIONS: The rate of neurologic injury for patients treated with rib-based distraction surgery was 1.7%. Most injuries occurred with congenital diagnoses and they were more likely in patients with additional secondary diagnoses. These injuries were predominantly to the brachial plexus and generally resolved.

Late transection of the sciatic nerve in association with an acetabular reconstruction cage.

We report a case of a late-onset sciatic nerve palsy that occurred in association with an acetabular reconstruction cage. On surgical exploration, the nerve was found to be completely transected secondary to abrasion over the posterior flange of the reconstruction cage.