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.

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.

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.

The Detection of 8-Oxo-7,8-Dihydro-2'-Deoxyguanosine in Circulating Cell-Free DNA: A Step Towards Longitudinal Monitoring of Health.

Chronic stress appears to accelerate biological aging, and oxidative damage is an important potential mediator of this process. Many chronic diseases are accompanied by an increase in overall oxidation of genomic DNA. In course of exposure to daily environmental insults, DNA accumulates oxidative damage, which is, in part, repaired, while the cells with the most damaged DNA die either by necrosis or by apoptosis. The oxidized DNA released from the dying cells contributes to the pool of cell-free/extracellular DNA present in plasma and other biological fluids. This cell-free DNA contains a great deal of 8-oxodG bases. The ratio of 8-oxo-dG and unmodified guanine may serve as a cumulative biomarker of stress encountered by a human body within a previous 24 h-period. This true end-point biomarker may outperform other short-lived molecules that reflect only the most current state of oxidant stress. Patient-specific baselines for oxidative damage may be established by measuring of 8-oxo-dG in circulating DNA. Longitudinal profiling of oxiDNA may aid in reliable quantification of the effects of various self-administered nutraceutical and lifestyle based health interventions. Development of wearable electrochemical sensor patches that will quantify oxiDNA in near real-time is warranted to produce life- and health-modifying event awareness feedback.

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.

The Role of MRI in Children With Congenital Limb Deficiencies With Associated Scoliosis.

BACKGROUND: The association of scoliosis and congenital limb deficiency has been well described. However, the incidence of neural axis abnormalities in this population is not known. The ability to assess the neural axis by physical examination may be limited in patients with a limb deficiency. Although mobility of the spine is important for all children, it can be especially so in children with a limb deficiency. As spinal fusion in children with limb deficiency potentially has more functional impact, detecting reversible forms of scoliosis seems particularly important. METHODS: Retrospective review of children treated at 1 institution between 1990 and 2017 with both a diagnosis of a congenital limb deficiency, upper or lower, and scoliosis. Children were excluded if they had any neurological difference on history or physical examination, if they had sacral agenesis or spina bifida, or if their limb deficiency was related to trauma or early amniotic rupture sequence. RESULTS: Twenty-four children were identified, 11 with lower extremity deficiency, 14 with upper extremity deficiency with 1 having both. Fifteen children demonstrated neural axis abnormalities, 6 (40%) required neurosurgery. Five (45%) of 11 lower extremity deficiency children had MRI findings, 3 of these needing neurosurgery. Of the 14 upper extremity deficiency children, 10 had MRI changes, and 3 required neurosurgery. Eight children with congenital scoliosis, 5 had MRI findings, with 4 children requiring neurosurgery. The other 16 children had scoliosis without vertebral abnormalities, 10 had MRI findings, and 2 required neurosurgery. CONCLUSIONS: There is a high incidence of neural axis abnormalities (63%) in children with congenital limb deficiencies and scoliosis. A large portion of these require neurosurgical intervention. MRI should be considered soon after presentation in this population of children. LEVEL OF EVIDENCE: Level IV. DESIGN: Retrospective cohort.

Patella Alta in Ambulatory Children With Cerebral Palsy: Prevalence and Functional Significance.

BACKGROUND: Gait dysfunction associated with patella alta (PA) in subjects with cerebral palsy (CP) has been presumed but not objectively established clinically or through biomechanical modeling. It is hypothesized that PA is associated with increasing level of motor impairment, increasing age, obesity, and worse stance phase knee kinematics and kinetics in children with CP. METHODS: Retrospective case series of 297 subjects with CP studied in our Motion Analysis Center. Data analyzed included patient demographics (age, body mass index, CP classification), patella height (Koshino-Sugimoto Index), and knee kinematics and kinetics. RESULTS: PA was present in 180 of 297 subjects (61%), in 68 of the 146 (47%) with unilateral CP, and 112 of 151 subjects (74%) with bilateral CP. For unilateral CP, the prevalence of PA was not significantly different between Gross Motor Function Classification System (GMFCS) I and II (P=0.357). For bilateral CP, the prevalence of PA in GMFCS III was significantly greater than in GMFCS I and II (P=0.02). Regression analysis showed a significant trend between increasing age and PA in unilateral and bilateral groups (P<0.001 and 0.001, respectively). The prevalence of PA was not significantly different across body mass index categories for either unilateral or bilateral groups. There were only 2 of 10 significant correlations between PA and gait parameters for subjects with unilateral CP functioning at the GMFCS I and II levels. There were 8 of 12 significant correlations between PA and gait parameters for subjects with bilateral CP functioning at the GMFCS I, II, and III levels. CONCLUSIONS: PA is common in ambulatory children with CP across topographic types and motor functional levels. PA is well tolerated with respect to gait dysfunction in unilateral CP, but may contribute to crouch gait in bilateral CP. Gait dysfunction cannot be inferred from the radiographic assessment of patellar height, and radiographic evidence of PA by itself does not justify surgical correction with patellar tendon advancement or shortening. LEVEL OF EVIDENCE: Level III-prognostic, retrospective 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.

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.

Influence of viral infection on the relationships between airway cytokines and lung function in asthmatic children.

BACKGROUND: Few longitudinal studies examine inflammation and lung function in asthma. We sought to determine the cytokines that reduce airflow, and the influence of respiratory viral infections on these relationships. METHODS: Children underwent home collections of nasal lavage during scheduled surveillance periods and self-reported respiratory illnesses. We studied 53 children for one year, analyzing 392 surveillance samples and 203 samples from 85 respiratory illnesses. Generalized estimated equations were used to evaluate associations between nasal lavage biomarkers (7 mRNAs, 10 proteins), lung function and viral infection. RESULTS: As anticipated, viral infection was associated with increased cytokines and reduced FVC and FEV1. However, we found frequent and strong interactions between biomarkers and virus on lung function. For example, in the absence of viral infection, CXCL10 mRNA, MDA5 mRNA, CXCL10, IL-4, IL-13, CCL4, CCL5, CCL20 and CCL24 were negatively associated with FVC. In contrast, during infection, the opposite relationship was frequently found, with IL-4, IL-13, CCL5, CCL20 and CCL24 levels associated with less severe reductions in both FVC and FEV1. CONCLUSIONS: In asthmatic children, airflow obstruction is driven by specific pro-inflammatory cytokines. In the absence of viral infection, higher cytokine levels are associated with decreasing lung function. However, with infection, there is a reversal in this relationship, with cytokine abundance associated with reduced lung function decline. While nasal samples may not reflect lower airway responses, these data suggest that some aspects of the inflammatory response may be protective against viral infection. This study may have ramifications for the treatment of viral-induced asthma exacerbations.

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.

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.

Role of renal urothelium in the development and progression of kidney disease.

The clinical and financial impact of chronic kidney disease (CKD) is significant, while its progression and prognosis is variable and often poor. Studies using the megabladder (mgb -/- ) model of CKD show that renal urothelium plays a key role in modulating early injury responses following the development of congenital obstruction. The aim of this review is to examine the role that urothelium has in normal urinary tract development and pathogenesis. We discuss normal morphology of renal urothelium and then examine the role that uroplakins (Upks) play in its development. Histologic, biochemical, and molecular characterization of Upk1b RFP/RFP mice indicated Upk1b expression is essential for normal urinary tract development, apical plaque/asymmetric membrane unit (AUM) formation, and differentiation and functional integrity of the renal urothelium. Our studies provide the first evidence that Upk1b is directly associated with the development of congenital anomalies of the urinary tract (CAKUT), spontaneous age-dependent hydronephrosis, and dysplastic urothelia. These observations demonstrate the importance of proper urothelial differentiation in normal development and pathogenesis of the urinary tract and provide a unique working model to test the hypothesis that the complex etiology associated with CKD is dependent upon predetermined genetic susceptibilities that establish pathogenic thresholds for disease initiation and progression.

Uroplakin 1b is critical in urinary tract development and urothelial differentiation and homeostasis.

Proper development and maintenance of urothelium is critical to its function. Uroplakins are expressed in developing and mature urothelium where they establish plaques associated with the permeability barrier. Their precise functional role in development and disease is unknown. Here, we disrupted Upk1b in vivo where its loss resulted in urothelial plaque disruption in the bladder and kidney. Upk1b(RFP/RFP) bladder urothelium appeared dysplastic with expansion of the progenitor cell markers, Krt14 and Krt5, increased Shh expression, and loss of terminal differentiation markers Krt20 and uroplakins. Upk1b(RFP/RFP) renal urothelium became stratified with altered cellular composition. Upk1b(RFP/RFP) mice developed age-dependent progressive hydronephrosis. Interestingly, 16% of Upk1b(RFP/RFP) mice possessed unilateral duplex kidneys. Our study expands the role of uroplakins, mechanistically links plaque formation to urinary tract development and function, and provides a tantalizing connection between congenital anomalies of the kidney and urinary tract along with functional deficits observed in a variety of urinary tract diseases. Thus, kidney and bladder urothelium are regionally distinct and remain highly plastic, capable of expansion through tissue-specific progenitor populations. Furthermore, Upk1b plays a previously unknown role in early kidney development representing a novel genetic target for congenital anomalies of the kidney and urinary tract.

Ribonucleases 6 and 7 have antimicrobial function in the human and murine urinary tract.

Recent evidence suggests antimicrobial peptides protect the urinary tract from infection. Ribonuclease 7 (RNase 7), a member of the RNase A superfamily, is a potent epithelial-derived protein that maintains human urinary tract sterility. RNase 7 expression is restricted to primates, limiting evaluation of its antimicrobial activity in vivo. Here we identified ribonuclease 6 (RNase 6) as the RNase A superfamily member present in humans and mice that is most conserved at the amino acid level relative to RNase 7. Like RNase 7, recombinant human and murine RNase 6 has potent antimicrobial activity against uropathogens. Quantitative real-time PCR and immunoblot analysis indicate that RNase 6 mRNA and protein are upregulated in the human and murine urinary tract during infection. Immunostaining located RNase 6 to resident and infiltrating monocytes, macrophages, and neutrophils. Uropathogenic E. coli induces RNase 6 peptide expression in human CD14(+) monocytes and murine bone marrow-derived macrophages. Thus, RNase 6 is an inducible, myeloid-derived protein with markedly different expression from the epithelial-derived RNase 7 but with equally potent antimicrobial activity. Our studies suggest RNase 6 serves as an evolutionarily conserved antimicrobial peptide that participates in the maintenance of urinary tract sterility.

Guinea pig ciliary muscle development.

PURPOSE: The purpose of this study was to develop a method for quantifying guinea pig ciliary muscle volume (CMV) and to determine its relationship to age and ocular biometric measurements. METHODS: Six albino guinea pigs' eyes were collected at each of five ages (n = 30 eyes). Retinoscopy and photography were used to document refractive error, eye size, and eye shape. Serial sections through the excised eyes were made and then labeled with an α-smooth muscle actin antibody. The ciliary muscle was then visualized with an Olympus BX51 microscope, reconstructed with Stereo Investigator (MBF Bioscience), and analyzed using Neurolucida Explorer (MBF Bioscience). Full (using all sections) and partial (using a subset of sections) reconstruction methods were used to determine CMV. RESULTS: There was no significant difference between the full and partial volume determination methods (p = 0.86). The mean (±SD) CMV of the 1-, 10-, 20-, 30-, and 90-day-old eyes was 0.40 (±0.16) mm, 0.48 (±0.13) mm, 0.67 (±0.15) mm, 0.86 (±0.35) mm, and 1.09 (±0.63) mm, respectively. Ciliary muscle volume was significantly correlated with log age (p = 0.001), ocular length (p = 0.003), limbal circumference (p = 0.01), and equatorial diameter (p = 0.003). It was not correlated with refractive error (p = 0.73) or eye shape (p = 0.60). Multivariate regression determined that biometric variables were not significantly associated with CMV after adjustment for age. CONCLUSIONS: Three-dimensional reconstruction was an effective means of determining CMV. These data provide evidence that ciliary muscle growth occurs with age in tandem with eye size in normal albino guinea pigs. Additional work is needed to determine the relationship between CMV and abnormal ocular growth.

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.