Development of a defibrinated human blood hemolysis assay for rapid testing of hemolytic activity compared to computational prediction.

Cytotoxicity studies determining hemolytic properties of antimicrobial peptides or other drugs are an important step in the development of novel therapeutics for clinical use. Hemolysis is an affordable, accessible, and rapid method for initial assessment of cellular toxicity for all drugs under development. However, variability in species of red blood cells and protocols used may result in significant differences in results. AMPs generally possess higher selectivity for bacterial cells but can have toxicity against host cells at high concentrations. Knowing the hemolytic activity of the peptides we are developing contributes to our understanding of their potential toxicity. Computational approaches for predicting hemolytic activity of AMPs exist and were tested head-to-head with our experimental results. RESULTS: Starting with an observation of high hemolytic activity of LL-37 peptide against human red blood cells that were collected in EDTA, we explored alternative approaches to develop a more robust, accurate and simple hemolysis assay using defibrinated human blood. We found significant differences between the sensitivity of defibrinated red blood cells and EDTA treated red blood cells. SIGNIFICANCE: Accurately determining the hemolytic activity using human red blood cells will allow for a more robust calculation of the therapeutic index of our potential antimicrobial compounds, a critical measure in their pre-clinical development. CONCLUSION: We introduce a standardized, more accurate protocol for assessing hemolytic activity using defibrinated human red blood cells. This approach, facilitated by the increased commercial availability of de-identified human blood and defibrination methods, offers a robust tool for evaluating toxicity of emerging drug compounds, especially AMPs.

Is peak hamstrings muscle-tendon length criterion a sufficient indicator to recommend against surgical lengthening of hamstrings?

BACKGROUND: Excessive knee flexion during stance in children with cerebral palsy is often treated by surgical hamstrings lengthening. Pre-operative hamstrings muscle-tendon length can be estimated from kinematics and often used for decision making to rule out surgical lengthening if peak hamstrings muscle-tendon length is 'Not Short'. RESEARCH QUESTION: If peak hamstrings muscle-tendon length is within two standard deviations of typical, is that a sufficient indicator to rule out surgical hamstrings lengthening? METHODS: Three motion analysis centers retrospectively identified children with cerebral palsy, age 6-17 years, who had consecutive gait analyses with knee flexion at initial contact > 20° and popliteal angle > 35° at initial study. Three groups were considered: Medial Hamstrings Lengthening (MHL), Medial and Lateral Hamstrings Lengthening (MLHL), no surgical intervention (Control). Peak hamstrings muscle-tendon length at initial gait study was computed and categorized as 'Short' or 'Not Short'. Two outcomes variables were considered: change in peak knee extension (PKE) and change in pelvic tilt. Univariate comparisons of all variables were assessed along with a multivariate stepwise regression analysis to identify pre-operative characteristics that may predict post-operative improvement. RESULTS: 440 individuals met inclusion criteria. Percentage of individuals with improved PKE by grouping were- MHL-'Short': 60%, MHL-'Not Short': 65%, MLHL-'Short': 74%, MLHL-'Not Short': 74%, Control 'Short': 20%, Control 'Not Short': 19%. Percentage of individuals with worsened pelvic tilt were- MHL-'Short': 25%, MHL-'Not Short': 11%, MLHL-'Short': 42%, MLHL-'Not Short': 21% with significantly more individuals in MHL-'Short' subgroup compared to MHL-'Not Short'. Multivariate analysis suggested that pre-operative pelvic tilt and weak hip extensor strength have the largest effect on predicting post-operative increase in APT. Peak muscle-tendon length was not a significant predictor of post-operative knee kinematics or increase in APT. SIGNIFICANCE: This study suggests that hamstrings muscle-tendon length criteria by itself is not a sufficient indicator to recommend against hamstrings lengthening.

GATR-3, a Peptide That Eradicates Preformed Biofilms of Multidrug-Resistant Acinetobacter baumannii.

Acinetobacter baumannii is a gram-negative bacterium that causes hospital-acquired and opportunistic infections, resulting in pneumonia, sepsis, and severe wound infections that can be difficult to treat due to antimicrobial resistance and the formation of biofilms. There is an urgent need to develop novel antimicrobials to tackle the rapid increase in antimicrobial resistance, and antimicrobial peptides (AMPs) represent an additional class of potential agents with direct antimicrobial and/or host-defense activating activities. In this study, we present GATR-3, a synthetic, designed AMP that was modified from a cryptic peptide discovered in American alligator, as our lead peptide to target multidrug-resistant (MDR) A. baumannii. Antimicrobial susceptibility testing and antibiofilm assays were performed to assess GATR-3 against a panel of 8 MDR A. baumannii strains, including AB5075 and some clinical strains. The GATR-3 mechanism of action was determined to be via loss of membrane integrity as measured by DiSC3(5) and ethidium bromide assays. GATR-3 exhibited potent antimicrobial activity against all tested multidrug-resistant A. baumannii strains with rapid killing. Biofilms are difficult to treat and eradicate. Excitingly, GATR-3 inhibited biofilm formation and, more importantly, eradicated preformed biofilms of MDR A. baumannii AB5075, as evidenced by MBEC assays and scanning electron micrographs. GATR3 did not induce resistance in MDR A. baumannii, unlike colistin. Additionally, the toxicity of GATR-3 was evaluated using human red blood cells, HepG2 cells, and waxworms using hemolysis and MTT assays. GATR-3 demonstrated little to no cytotoxicity against HepG2 and red blood cells, even at 100 µg/mL. GATR-3 injection showed little toxicity in the waxworm model, resulting in a 90% survival rate. The therapeutic index of GATR-3 was estimated (based on the HC50/MIC against human RBCs) to be 1250. Overall, GATR-3 is a promising candidate to advance to preclinical testing to potentially treat MDR A. baumannii infections.

Terminal Syme Amputation of the Great Toe in the Pediatric Population.

BACKGROUND: In the pediatric population, chronic ingrown toenails (onychocryptosis) can cause infection (paronychia), debilitating pain, and may be unresponsive to conservative treatments. Following multiple failed interventions, a terminal Syme amputation is one option for definitive treatment of chronic onychocryptosis. This procedure involves amputation of the distal aspect of the distal phalanx of the great toe with complete removal of the nail bed and germinal center, preventing further nail growth and recurrence. METHODS: A retrospective review was performed to determine outcomes of a terminal Syme amputation in the pediatric population. Inclusion criteria included treatment of onychocryptosis involving terminal Syme amputation with a minimum follow-up of 1 year. The medical record was reviewed to assess previous failed treatment efforts, perioperative complications, radiographic outcomes, and the need for additional procedures. RESULTS: From 1984 to 2017, 11 patients (13 halluces) with onychocryptosis were treated with a terminal Syme amputation. There were no intraoperative complications. One hallux had a postoperative infection requiring antibiotics as well as partial nail regrowth following the terminal Syme procedure that required subsequent removal of the residual nail. Following partial nail ablation, the patient had no further nail growth. An additional patient also developed a postoperative infection requiring oral antibiotic treatment. All patients returned to full weight-bearing physical activities within 6 weeks of surgery. CONCLUSIONS: Terminal Syme amputation was successful in treating pediatric patients who have recalcitrant onychocryptosis and paronychia. There was little functional consequence following terminal Syme amputation of the great toe in this patient population, making it an effective salvage procedure. LEVEL OF EVIDENCE: Level IV-retrospective comparative study.

Patient-Reported Outcome Measurement Information System (PROMIS) Scores in Pediatric Patients With Arthrogryposis.

BACKGROUND: Arthrogryposis multiplex congenita (AMC) is a clinical term that is used to describe congenital contractures that lead to childhood deformities. Treatment aims are to maximize function while minimizing pain and disability. Few studies have explored patient-reported outcomes in the pediatric arthrogrypotic population, particularly concerning mobility. The aim of this study was to report scores for the Patient-Reported Outcome Measurement Information System (PROMIS) questionnaire for pediatric patients with arthrogryposis with regards to mobility, upper extremity (UE) function, pain interference, and peer relationships. METHODS: A retrospective chart review of 76 patients with AMC aged 5 to 17 who completed the PROMIS questionnaire between January 1, 2017 to March 24, 2020 was performed. Results were collected for four domains: mobility, UE function, pain interference, and peer relationships. Outcomes were stratified by type of arthrogryposis: Amyoplasia (Am), Distal Arthrogryposis (DA), and Other Diagnoses (OD). Results of subjects with isolated upper or lower extremity involvement were compared with subjects with involvement of upper and/or lower extremities. Outcomes were correlated with history of surgical intervention. RESULTS: Children with Am and OD demonstrated moderate impairment of mobility (average: 35.2 and 35.9, respectively), while those with DA reported only mild impairment (average: 44.9). UE function was severely impaired for children with Am (average: 23.0), moderately impaired for OD (average: 33.0), and mildly impaired for DA (average: 43.4). All patient groups reported normal ranges of pain interference, as well as good peer relationships. A moderate negative correlation between number of surgical interventions and mobility scores, and a weak negative correlation between number of surgeries and pain interference scores were found. CONCLUSIONS: Children with AMC experience limited mobility and UE function, but normal levels of pain interference and good peer relationships. The average values provided in this study will serve as a baseline from which to evaluate the efficacy of both nonoperative and surgical interventions. LEVEL OF EVIDENCE: Level II-prognostic study; retrospective study.

Outcomes of Patellar Tendon Imbrication With Distal Femoral Extension Osteotomy for Treatment of Crouch Gait.

BACKGROUND: Crouch gait is a frequent gait abnormality observed in children with cerebral palsy. Distal femoral extension osteotomy (DFEO) with the tightening of the extensor mechanism is a common treatment strategy to address the pathologic knee flexion contracture and patella alta. The goal of this study was to review the results of a patellar tendon imbrication (PTI) strategy to address quadriceps insufficiency in the setting of children undergoing DFEO. METHODS: After institutional review board approval, all patients with crouch gait treated at a single institution with DFEO and PTI were identified. Clinical, radiographic, and instrumented gait analysis data were analyzed preoperatively and at 1 year following surgery. RESULTS: Twenty-eight patients (54 extremities) with a diagnosis of cerebral palsy and crouch gait were included. Significant improvements were appreciated in the degree of knee flexion contracture, quadriceps strength, knee extensor lag, and popliteal angle (P<0.01). Knee flexion at initial contact and during mid-stance improved significantly (P<0.0001), and knee moments in late stance were significantly reduced (P<0.01). The anterior pelvic tilt, however, significantly increased postoperatively (P<0.0001). Radiographic improvements were seen in the knee flexion angle and patellar station as assessed by the Koshino Sugimoto Index (P<0.0001). Four patients (14.2%) developed a recurrence of knee flexion contracture requiring further intervention. CONCLUSIONS: PTI is a simplified and safe technique to address quadriceps insufficiency when performing DFEO. The short-term results of patients who underwent DFEO with PTI demonstrated improvements in clinical, radiographic, and gait analysis variables of the knee. Investigating long-term outcomes, comparing techniques, and assessing quality of life measures are important next steps in research. LEVEL OF EVIDENCE: Level IV-case series.

Surgical Outcomes for Severe Idiopathic Toe Walkers.

BACKGROUND: Idiopathic toe walking (ITW) is a diagnosis of exclusion and represents a spectrum of severity. Treatment for ITW includes observation and a variety of conservative treatment methods, with surgical intervention often reserved for severe cases. Previous studies reviewing treatment outcomes are often difficult to interpret secondary to a mixture of case severity. The goal of this study was to review surgical outcomes in patients with severe ITW who had failed prior conservative treatment, as well as determine differences in outcomes based on the type of surgery performed. METHODS: After IRB approval, all patients with surgical management of severe ITW at a single institution were identified. Zone II or zone III plantar flexor lengthenings were performed in all subjects. Clinical, radiographic, and motion analysis data were collected preoperatively and at 1 year following surgery. RESULTS: Twenty-six patients (46 extremities) with a diagnosis of severe ITW from 2002 to 2017 were included. Zone II lengthenings were performed in 25 extremities (mean age=9.9 y) and zone III lengthenings were performed in 21 extremities (mean age=8.6 y). At the most recent follow-up, 100% of zone III lengthening extremities and 88% of zone II lengthening demonstrated decreased severity of ITW. Six extremities required additional treatment, all of which were initially managed with zone II lengthenings. CONCLUSIONS: Severe ITW or ITW that has not responded to conservative treatment may benefit from surgical intervention. More successful outcomes, including continued resolution of toe walking, were observed in subjects treated with zone III lengthenings. LEVEL OF EVIDENCE: Level III-case series.

Outcomes of knee arthrodesis in proximal femoral focal deficiency.

Treatment options for patients with severe forms of proximal femoral focal deficiency include limb salvage procedures or foot ablation and use of a prosthesis. In patients with amputation, an ipsilateral knee arthrodesis can provide an efficient lever arm that is easy to contain in a prosthetic socket. We performed a retrospective review of proximal femoral focal deficiency patients treated at a single institution with knee arthrodesis. From 1986 to 2018, 26 patients (18 males, eight females) met study inclusion criteria (mean follow-up 13.2 years). Aitken C or D deformities were present in 65% of extremities. Ten patients had concomitant knee fusion with foot ablation (mean age 4.3 years). Fifteen patients had staged procedures with initial foot ablation (mean age 1.3 years) followed by a knee arthrodesis (mean age 4.7 years). One patient was managed with knee arthrodesis and retention of a three-ray foot. Subsequent realignment osteotomies were required in six patients to correct progressive malalignment with growth, often due to retained physis or incomplete physeal resection during the arthrodesis. In severe forms of proximal femoral focal deficiency, a straight residual limb can be achieved with foot ablation and knee arthrodesis to improve weight-bearing alignment in an above knee prosthesis. Progressive deformity, which may interfere with prosthetic fitting and require repeat osteotomy, may occur if complete excision of the physis is not achieved.

Calcaneocuboid distraction arthrodesis for children with symptomatic pes planovalgus: does fixation improve outcomes?

Lateral column lengthening is a common surgical procedure for addressing symptomatic pes planovalgus foot deformity. For more severe cases, the use of a calcaneocuboid distraction arthrodesis (CCDA) can allow for more powerful correction. Previous reports have cited an increased risk of graft collapse with loss of correction when this procedure is performed without supplemental hardware fixation. The purpose of this study was to assess the outcomes of CCDA in children with and without supplemental locking fixation. A retrospective review from 2008 to 2016 of CCDA procedures with and without supplemental fixation was performed. The primary endpoint was graft collapse. Secondary objectives included evaluation of radiographic loss of correction, hardware failure, pain at 1-year follow-up, reoperations, and changes in the foot loading pattern foot per pedobarography. Twenty-nine feet in 24 patients were eligible for review. Supplemental locked fixation was used in 18 feet [hardware (HW)], with the remaining 11 feet managed without fixation [no hardware (NoHW)]. The overall failure rate on the basis of graft collapse and loss of correction was 55% (56% for the HW group, 55% for the NoHW group). Eleven patients (61%) in the HW group experienced hardware failure, with six (33%) of these requiring hardware removal. Fifty-six percent of the HW group and 45% of the NoHW group reported continued pain at 1-year follow-up. One patient from each group underwent revision arthrodesis. Supplemental locked fixation did not provide additional benefit in preventing graft collapse and loss of correction in this cohort. Alternative strategies should be considered to improve the outcomes for this procedure.

Outcomes of Naviculectomy for Severe Recurrent Clubfoot Deformity.

BACKGROUND: Naviculectomy was originally described for resistant congenital vertical talus deformity but was later expanded to use in rigid cavus deformity. This study reviews the operative outcomes of complete excision of the navicular for recurrent deformity in the talipes equinovarus (TEV) population. METHODS: After institutional review board approval, all patients undergoing naviculectomy at a single institution were identified. Clinical, radiographic, and pedobarographic data (minimum 2 years' follow-up) were reviewed. RESULTS: Twelve patients (14 feet) with TEV from 1984 to 2019 were included. All feet had minimum 1 prior operative intervention on the affected foot (mean age = 4.0 years, range 0.2-14.5), with 8/14 having at least 3 prior operative procedures. Complete navicular excision with concomitant procedures was performed in all patients (mean age = 11.7 years, range 5.5-16.1). Mean clinical follow-up from naviculectomy was 5.1 years (range, 2.2-11.2). During follow-up, 6 patients required subsequent surgery, most often secondary to pain and progressive deformity. One patient underwent elective below-knee amputation of the affected extremity. Of the remaining 11 patients, 7 of 11 reported continued pain and 8 of 11 maintained adequate range of motion at the ankle at the most recent follow-up. CONCLUSION: Clinical follow-up demonstrated deteriorating results in a large percentage of patients. The high rate of additional procedures and continued pain in the current series suggests that even as a salvage procedure, naviculectomy may not provide adequate results for patients. LEVEL OF EVIDENCE: Level IV, case series.

Guided Growth for Ankle Valgus Deformity: The Challenges of Hardware Removal.

BACKGROUND: Ankle valgus deformity is associated with conditions such as clubfoot, cerebral palsy, and myelodysplasia. Guided growth strategies using a transphyseal screw provide effective correction of ankle valgus deformity. When correction occurs before skeletal maturity, screw removal is required to prevent overcorrection in the coronal plane. In this study, we reviewed the outcomes of guided growth procedures for correction of ankle valgus and related difficulty with hardware extraction. METHODS: A retrospective review of patients with ankle valgus managed with transphyseal screw placement was performed. Clinical and radiographic data, including the lateral distal tibial angle (LDTA), type of screw placed, and time to correction was recorded. At hardware removal, we reviewed elements associated with difficult extraction defined as requiring the use of specialized screw removal/extraction sets or inability to remove the entirety of the screw. RESULTS: One hundred nineteen patients (189 extremities) with a mean age of 11.7 years at time of screw placement met study inclusion criteria. Following correction of the valgus deformity, hardware removal occurred at an average of 18.4 months after placement of the screw. Preoperatively, the mean LDTA for the entire cohort was 81.3 degrees, and was corrected to a mean LDTA of 91.1 degrees. Complicated hardware removal occurred in 69 (37%) extremities. These 69 extremities had hardware in place an average of 1.8 years compared with an average of 1.4 years in extremities without difficult extraction (P<0.01). Six (9%) screws were unable to be removed in their entirety. Rebound valgus deformity occurred in 5 extremities (3%). CONCLUSIONS: Extraction of transphyseal screws in the correction of ankle valgus can be problematic. Specialized instrumentation was required in approximately one third of cases. Longevity of screw placement may be a factor that affects the ease of extraction. Additional exposure, access to specialized instrumentation, and additional operative time may be required for extraction. LEVEL OF EVIDENCE: Level IV-case series.

Management of Tibial Bow in Fibular Deficiency.

BACKGROUND: Deformity of the tibia, including shortening and angulation, may accompany severe forms of postaxial hypoplasia (fibular deficiency). The current literature reflects varying opinions on the appropriate management for tibial deformity in the setting of fibular deficiency. METHODS: We performed a retrospective review to determine outcomes of tibial deformity correction in patients with a primary diagnosis of fibular deficiency. Clinical and radiographic outcomes of patients treated with foot ablation were reviewed to establish indications for tibial deformity correction, identify occurrence of additional surgical procedures related to limb alignment or deformity, and characterize difficulties with prosthetic wear potentially related to residual or recurrent tibial deformity. RESULTS: From 1989 to 2016, 51 patients (57 extremities) with fibular deficiency were managed with a foot ablation procedure. Twenty-five (44%) had simultaneous correction of the tibial deformity. The initial tibial deformity measured 42.5 degrees, was corrected to 5.6 degrees intraoperatively, and measured 18.6 degrees at follow-up, suggesting recurrent deformity. In follow-up, approximately half of the patients complained of redness and one third complained of a continued prominence along the anterior tibia. Thirty-two extremities had an isolated foot ablation procedure without tibial osteotomy. Radiographic review demonstrated mild tibial bowing at the time of amputation with a mean angular deformity of 15.4 degrees and remained unchanged during the follow-up period (mean, 12.7 degrees). Similar to the osteotomy group, approximately half of the patients complained of redness and erythema over the anterior bow, with one fourth noting prominence, and only 2 reporting significant pain. CONCLUSIONS: Tibial osteotomies in patients with more significant degrees of angular deformity can be safely performed at the same setting as foot ablative procedures for fibular deficiency. Recurrent deformity with growth may occur. Patients and their caregivers should be aware that rebound deformity may occur, but typically can be managed with prosthetic adjustment and without significant disruption to the child's daily activities. LEVEL OF EVIDENCE: Level IV (case series).

Correction of Genu Valgum in Patients With Congenital Fibular Deficiency.

BACKGROUND: Patients with congenital fibular deficiency often develop genu valgum secondary to lateral femoral condylar hypoplasia. Guided growth strategies are often performed to correct limb alignment when adequate skeletal growth remains. METHODS: A retrospective review of patients with postaxial hypoplasia of the lower extremity managed with an amputation strategy and who had a guided growth procedure for coronal plane limb malalignment during their course of treatment was performed. Clinical and radiographic data, including measures of coronal plane deformity and alignment, type of amputation, subsequent operative procedures, and complications were recorded. RESULTS: Seventeen patients (20 extremities) met study inclusion criteria (mean follow-up 8.8 y). Foot ablation and hemiepiphysiodesis for valgus deformity of the knee was performed in all extremities. The average age at the time of initial hemiepiphysiodesis was 11.2 years at an average of 8.8 years from the initial amputation procedure. The mean preoperative mechanical axis deviation was 26.5 mm, which was corrected to a mean mechanical axis deviation of 7.0 mm. Fifteen (75%) of the extremities had correction of the deformity to neutral alignment after the initial procedure. Lack of correction occurred in 3 extremities, and overcorrection occurred in 2 extremities. Additional procedures were required in 5 extremities for rebound valgus deformity after hardware removal. CONCLUSIONS: In patients with postaxial hypoplasia, regular monitoring of the residual limb for growth-related changes must occur to ensure optimal function and prosthetic fit. Timing of the guided growth procedure is critical, as younger patients may be more likely to experience rebound deformity. Families and patients should be made aware that growth might be unpredictable in this population with risks of both overcorrection and undercorrection. LEVEL OF EVIDENCE: Level IV-case series.

3D Modeling of Lower Extremities With Biplanar Radiographs: Reliability of Measures on Subsequent Examinations.

BACKGROUND: Biplanar radiography with 3-dimensional (3D) modeling (EOS) provides a comprehensive assessment of lower limb alignment in an upright weight-bearing position with less radiation than conventional radiography. A study was performed to assess the consistency and reliability of 2 lower extremity 3D biplanar radiograph models created at least 1 year apart in a pediatric population. METHODS: All patients who had 2 lower extremity radiographic evaluations with EOS performed at visits a minimum of 1 year apart were reviewed. Digital radiographs, of lower extremities in both frontal and sagittal planes, were acquired simultaneously, using the EOS system. The 3D reconstruction of the images was achieved utilizing the SterEOS software. Pelvic position, femoral and tibial anatomy, and the torsional profile were evaluated and compared using t tests. RESULTS: In total, 53 patients with a mean age of 11.7 years (range, 6.1 to 18.9 y) met inclusion criteria. When comparing 3D models between visits, minimal differences were noted in proximal femoral anatomy and pelvic alignment (pelvic incidence, sacral slope, sagittal tilt, neck shaft angle). Expected differences in femoral and tibial length corresponded with normal longitudinal growth between visits. Sagittal plane knee position varied widely between examinations. Femoral and/or tibial rotational osteotomies were performed in 37% of extremities between examinations. After femoral derotational osteotomy, a significant difference in femoral anteversion was appreciated when comparing preoperative and postoperative 3D models. However, this difference was less than the expected difference based on the anatomic correction achieved intraoperatively. No differences were noted in tibial torsion measures after tibial derotational osteotomy. CONCLUSIONS: The 3D modeling based on biplanar radiographs provides consistent and reliable measures of pelvic and hip joint anatomy of the lower extremity. Patient positioning may influence the reproducibility of knee alignment. The torsional profile assessment did not accurately reflect changes obtained by derotational osteotomy. LEVEL OF EVIDENCE: Level III.

Optimization of Casting in Early-onset Scoliosis.

BACKGROUND: Early-onset scoliosis is a spine deformity that presents before the age of 3 years. When compared with age-matched controls, children with the condition are known to be at risk for significant morbidity and mortality. Although many works support the use of casting for this condition, the key technical factors to optimize the outcomes of casting are not clear. This work was designed to evaluate the role of frequency of radiographic imaging and over the shoulder straps in the outcomes of casting. METHODS: Two surgeons at 2 centers followed nearly identical protocols for applying casts for early-onset scoliosis. At center A, the surgeon hoped to improve outcomes by obtaining radiographs after each cast and by reinforcing the cast with shoulder straps. At center B, the surgeon did not use shoulder straps and limited radiographs to once every 6 months. Children were included if they were 3 years or below of age and had a curve of ≥50 degrees at the time of the first cast and had a minimum of 3 years of follow-up. Center was used as a variable in a multivariable regression that also included: age at first cast, initial curve magnitude, and presence of a syrinx or genetic syndrome with the outcome of curve resolution. RESULTS: There were 40 children at center A, 9 of whom experienced resolution of their scoliosis. There were 36 children at center B, and 11 demonstrated scoliosis resolution. At center A, 2 of 10 children with a syrinx or genetic syndrome demonstrated curve resolution while 7 of 30 without these comorbidities did. At center B 3 of 10 children with a syrinx or genetic syndrome had curve resolution while 8 of 26 children without these comorbidities did. CONCLUSIONS: The children in group A demonstrated results very similar to the children of group B. Thus, the extra burden of shoulder straps and frequent radiographs are unnecessary. LEVEL OF EVIDENCE: Level III.

Amputation Outcomes in Congenital Pseudarthrosis of the Tibia.

BACKGROUND: Successful radiographic union in the treatment of congenital pseudarthrosis of the tibia (CPT) may be complicated by persistent pain, recurrent fracture, and poor function necessitating further intervention, including amputation. The long-term functional, radiographic, and clinical outcomes of patients who have undergone amputation as treatment for CPT are unknown. METHODS: A retrospective study of patients with a diagnosis of CPT secondary to neurofibromatosis and eventual treatment with amputation were included. Clinical and radiographic data, including initial Crawford classification, type of amputation, subsequent operative procedures, and evidence of radiographic healing were collected. RESULTS: A total of 17 patients with a mean age of 4.5 years (range, 0.7 to 9.2 y) at the time of amputation met inclusion criteria. Clinical follow-up averaged 11.1 years (range, 2.1 to 18.4 y), with radiographic follow-up averaging 9.1 years (range, 2.1 to 16.4 y). The mean number of surgeries before amputation was 2.2 procedures. Four patients underwent amputation as the primary procedure (3 Boyd, 1 below knee amputation (BKA)). At the time of amputation, a Boyd amputation was performed in 13 patients with stabilization of the pseudoarthrosis achieved with retrograde Rush rodding of the tibia and local autograft. A transtibial amputation (BKA) was performed in 4.After the Boyd procedure, 4 of the 13 patients (31%) demonstrated persistent nonunion of the pseudoarthrosis and required secondary procedures to gain union. At the most recent follow-up, 12 of 13 patients demonstrated successful radiographic healing of the pseudoarthrosis. Two patients, one for persistent pain and the other for refracture, were later converted to a BKA during the late teen years. All patients functioned well with the use of prosthetic devices. CONCLUSIONS: Union of the pseudoarthrosis occurred in >90% of cases following amputation. However, secondary procedures were required in 13 of the 17 patients (76%). Early amputation in the treatment of CPT provides a stable extremity and potential for a high level of function with the use of an adequate prosthesis. LEVEL OF EVIDENCE: Level IV-case series.

Results of Casting in Severe Curves in Infantile Scoliosis.

BACKGROUND: Previous work has demonstrated best results for casting in infantile scoliosis when the curves are small and the child begins casting under 2 years of age. This study examines if casting can delay the need for growth friendly instrumentation in severe curves (50 to 106 degrees) and how the comorbidities of syrinx or genetic syndromes affected outcomes. METHODS: All children undergoing casting for scoliosis at a single institution over an 8-year period were examined. Inclusion criteria included initial curve at first casting of ≥50 degrees, age ≤3 years at the start of casting, and a minimum follow-up of 3 years. Of 148 children undergoing casting during this period, 44 met our inclusion criteria. All children underwent magnetic resonance imaging. Ten children with a syrinx were identified. Ten children had known genetic syndromes (2 who also had a syrinx). The 26 children without these comorbidities were considered idiopathic. Curve magnitude ranged from 50 to 106 degrees. RESULTS: Nine of the 26 (35%) children in the children with idiopathic curves demonstrated resolution of their curves, while only 3 of the remaining 18 (17%) did. Of the children that did not have resolution of their curves, 14 were maintained over the entire follow-up period to within 15 degrees of their initial curve and 13 were improved 15 degrees or more. Only 5 children had an increase of 15 degrees or more over the follow-up period and 4 of these have undergone growth friendly instrumentation after a mean delay from initial cast of 71 months (range, 18 to 100 mo). CONCLUSION: This study demonstrates that even in severe curves, casting was effective in delaying instrumentation in all cases, and led to curve resolution of the curves in 12 of 44 children. LEVEL OF EVIDENCE: Level III-case control study.