A Shadow of Doubt: Is There Implicit Bias Among Orthopaedic Surgery Faculty and Residents Regarding Race and Gender?

BACKGROUND

Orthopaedic surgery continues to be one of the least diverse medical specialties. Recently, increasing emphasis has been placed on improving diversity in the medical field, which includes the need to better understand existing biases. Despite this, only about 6% of orthopaedic surgeons are women and 0.3% are Black. Addressing diversity, in part, requires a better understanding of existing biases. Most universities and residency programs have statements and policies against discrimination that seek to eliminate explicit biases. However, unconscious biases might negatively impact the selection, training, and career advancement of women and minorities who are underrepresented in orthopaedic surgery. Although this is difficult to measure, the Implicit Association Test (IAT) by Project Implicit might be useful to identify and measure levels of unconscious bias among orthopaedic surgeons, providing opportunities for additional interventions to improve diversity in this field.

QUESTIONS/PURPOSES

(1) Do orthopaedic surgeons demonstrate implicit biases related to race and gender roles? (2) Are certain demographic characteristics (age, gender, race or ethnicity, or geographic location) or program characteristics (geographic location or size of program) associated with the presence of implicit biases? (3) Do the implicit biases of orthopaedic surgeons differ from those of other healthcare providers or the general population?

METHODS

A cross-sectional study of implicit bias among orthopaedic surgeons was performed using the IAT from Project Implicit. The IAT is a computerized test that measures the time required to associate words or pictures with attributes, with faster or slower response times suggesting the ease or difficulty of associating the items. Although concerns have been raised recently about the validity and utility of the IAT, we believed it was the right study instrument to help identify the slight hesitation that can imply differences between inclusion and exclusion of a person. We used two IATs, one for Black and White race and one for gender, career, and family roles. We invited a consortium of researchers from United States and Canadian orthopaedic residency programs. Researchers at 34 programs agreed to distribute the invitation via email to their faculty, residents, and fellows for a total of 1484 invitees. Twenty-eight percent (419) of orthopaedic surgeons and trainees completed the survey. The respondents were 45% (186) residents, 55% (228) faculty, and one fellow. To evaluate response biases, the respondent population was compared with that of the American Academy of Orthopaedic Surgeons census. Responses were reported as D-scores based on response times for associations. D-scores were categorized as showing strong (≥ 0.65), moderate (≥ 0.35 to < 0.65), or slight (≥ 0.15 to < 0.35) associations. For a frame of reference, orthopaedic surgeons' mean IAT scores were compared with historical scores of other self-identified healthcare providers and that of the general population. Mean D-scores were analyzed with the Kruskal-Wallis test to determine whether demographic characteristics were associated with differences in D-scores. Bonferroni correction was applied, and p values less than 0.0056 were considered statistically significant.

RESULTS

Overall, the mean IAT D-scores of orthopaedic surgeons indicated a slight preference for White people (0.29 ± 0.4) and a slight association of men with career (0.24 ± 0.3), with a normal distribution. Hence, most respondents' scores indicated slight preferences, but strong preferences for White race were noted in 27% (112 of 419) of respondents. There was a strong association of women with family and home and an association of men with work or career in 14% (60 of 419). These preferences generally did not correlate with the demographic, geographic, and program variables that were analyzed, except for a stronger association of women with family and home among women respondents. There were no differences in race IAT D-scores between orthopaedic surgeons and other healthcare providers and the general population. Gender-career IAT D-scores associating women with family and home were slightly lower among orthopaedic surgeons (0.24 ± 0.3) than among the general population (0.32 ± 0.4; p < 0.001) and other healthcare professionals (0.34 ± 0.4; p < 0.001). All of these values are in the slight preference range.

CONCLUSION

Orthopaedic surgeons demonstrated slight preferences for White people, and there was a tendency to associate women with career and family on IATs, regardless of demographic and program characteristics, similar to others in healthcare and the general population. Given the similarity of scores with those in other, more diverse areas of medicine, unconscious biases alone do not explain the relative lack of diversity in orthopaedic surgery.

CLINICAL RELEVANCE

Implicit biases only explain a small portion of the lack of progress in improving diversity, equity, inclusion, and belonging in our workforce and resolving healthcare disparities. Other causes including explicit biases, an unwelcoming culture, and perceptions of our specialty should be examined. Remedies including engagement of students and mentorship throughout training and early career should be sought.

Comparison of nonoperative versus operative management in pediatric gustilo-anderson type I open tibia fractures

BACKGROUND

Recent studies suggest pediatric Gustilo-Anderson type I fractures, especially of the upper extremity, may be adequately treated without formal operative debridement, though few tibial fractures have been included in these studies. The purpose of this study is to provide initial data suggesting whether Gustilo-Anderson type I tibia fractures may be safely treated nonoperatively.

METHODS

Institutional retrospective review was performed for children with type I tibial fractures managed with and without operative debridement from 1999 through 2020. Incomplete follow-up, polytrauma, and delayed diagnosis of greater than 12 h since the time of injury were criteria for exclusion. Data including age, sex, mechanism of injury, management, time-to-antibiotic administration, and complications were recorded.

RESULTS

Thirty-three patients met inclusion criteria and were followed to union. Average age was 9.9 ± 3.7 years. All patients were evaluated in the emergency department and received intravenous antibiotics within 8 h of presentation. Median time-to-antibiotics was 2 h. All patients received cefazolin except one who received clindamycin at an outside hospital and subsequent cephalexin. Three patients (8.8%) received augmentation with gentamicin. Twenty-one patients (63.6%) underwent operative irrigation and debridement (I&D), and of those, sixteen underwent surgical fixation of their fracture. Twelve (36.4%) patients had bedside I&D with saline under conscious sedation, with one requiring subsequent operative I&D and intramedullary nailing. Three infections (14.3%) occurred in the operative group and none in the nonoperative group. Complications among the nonoperative patients include delayed union (8.3%), angulation (8.3%), and refracture (8.3%). Complications among the operative patients include delayed union (9.5%), angulation (14.3%), and one patient experienced both (4.8%). Other operative group complications include leg-length discrepancy (4.8%), heterotopic ossification (4.8%), and symptomatic hardware (4.8%).

CONCLUSION

No infections were observed in a small group of children with type I tibia fractures treated with bedside debridement and antibiotics, and similar non-infectious complication rates were observed relative to operative debridement. This study provides initial data that suggests nonoperative management of type I tibial fractures may be safe and supports the development of larger studies.

Pediatric fractures following implant removal: A systematic review

OBJECTIVES

To evaluate the available literature for postoperative fracture rates following implant removal in the pediatric population.

METHODS

A systematic review of articles in the PubMed and Embase computerized literature databases from January 2000 to June 2022 was performed using PRISMA guidelines. Randomized controlled trials, case-control studies, cohort studies (retrospective and prospective), and case series involving pediatric patients that included data on fracture rate following removal of orthopedic implants were eligible for review. Two authors independently extracted data from selected studies for predefined data fields for implant type, anatomic location of the implant, indication for implantation, fracture or refracture rate following implant removal, mean time to implant removal, and mean follow-up time.

RESULTS

Fifteen studies were included for qualitative synthesis. Reported fracture rates following implant removal vary based on several factors, with an overall reported incidence of 0%-14.9%. The available literature did not offer sufficient data for conduction of a meta-analysis.

CONCLUSION

Our systematic review demonstrates that fracture following implant removal in pediatric patients is a relatively frequent complication. In children, the forearm and femur are the most commonly reported sites of fracture following removal of implants. Traumatic fractures treated definitively with external fixation have the highest reported aggregate rate of refracture. Knowledge of the incidence of this risk is important for orthopedic surgeons. There remains a need for well-designed studies and trials to further clarify the roles of the variables that contribute to this complication.

Analysis of risk factors for nonunion in pediatric lateral column lengthening

The lateral column lengthening procedure is a commonly used osteotomy for correction of pes planus performed by inserting a graft in the anterior aspect of the calcaneus through a transverse osteotomy. Though nonunion and calcaneo-cuboid subluxation have been previously reported, these complications have not been extensively studied in pediatric patients. After IRB approval, 111 patients (151 feet) who underwent lateral column lengthening at a single institution were identified. Fifty-three females (70 feet) and 58 males (81 feet) with an average age of 11.4 years (2.6 SD; range 5-17) were analyzed. The primary outcome was nonunion defined as a lack of radiographic evidence of osteotomy healing by 9 months. Underlying diagnosis, pre and postoperative radiographic measurements, age, operative technique, fixation, calcaneo-cuboid subluxation, graft material and concomitant procedures were analyzed for their relationship to nonunion. Nonunion occurred in 7 of 151 feet (4.6%). Patient age at the time of surgery and calcaneo-cuboid subluxation trended toward a significant association with nonunion ( P  = 0.053, 0.054, respectively). The degree of surgical correction, as determined by radiographic analysis, and the use of calcaneo-cuboid fixation were not significantly associated with nonunion. None of the other factors evaluated were significantly associated with nonunion. There were three cases of postoperative infections (2.0%), two were superficial and 1 (0.7%) was deep. Thirty-five of 151 feet disclosed radiographic evidence of subluxation. Excluding subluxation, the overall complication rate was 8.6%. Nonunion occurred in 4.6% of pediatric feet undergoing lateral column lengthening. Fixation type was not significantly associated with nonunion. Older age at the time of surgery and calcaneocuboid subluxation trended towards significance. The placement of a calcaneo-cuboid pin was not found to be a significant factor in preventing calcaneo-cuboid subluxation or nonunion.

Increased open fracture complications following pediatric all-terrain vehicle accidents

BACKGROUND

ATV (All-Terrain Vehicle) related open fractures are often high energy and may be highly contaminated. We asked whether they were more complicated than other open fractures in pediatric patients.

METHODS

A retrospective chart review was performed comparing ATV associated open fractures to open fractures sustained in non-ATV related accidents. 97 pediatric open fractures from 2015 to 2021 were identified based on ICD-10 codes. Of these fractures, 62 were non-ATV related and 35 were ATV related. Charts were reviewed to collect basic demographics, fracture pattern, Gustilo-Anderson classification, procedures performed, operative findings, and complications.

RESULTS

Our cohort was predominantly male (71% in the ATV group and 76% in the non-ATV group). White race was more common in both the ATV (28 (80%)) and non-ATV (50(78%)) groups. The distribution of AO/OTA fractures was significantly different (p = 0.046), with humerus fractures being more common in the ATV group (8 (22%)) vs. non-ATV group (6 (9.3%)). The ATV group had a higher proportion of more severe type II and III open fractures with 77.1% (n = 27), versus 56% (n = 35) in the non-ATV group (p = 0.020).. Revision and reoperation were more likely in the ATV group (16 (23%)) vs. the non-ATV group (12 (15%)), as was malunion (ATV group 3 (4.3%) Vs. non-ATV 0 (0%)).

CONCLUSION

Open fractures resulting from ATV injuries tend to be more complex and have higher rates of revision and malunion. This information supports the large body of evidence on the dangers of ATVs to children and can help guide expectations of both clinicians and family members of patients presenting with these injuries.

Radiographic pseudosubluxation of the shoulder in pediatric proximal humeral fractures

This study was undertaken to determine the incidence, need for intervention, and time to resolution of pseudosubluxation of the shoulder in pediatric proximal humerus fractures. One hundred and ninety-nine radiographs (199 x-rays) were analyzed for pseudosubluxation of the shoulder following pediatric proximal humeral fractures. Pseudosubluxation occurs when the center of the humeral head aligns with the inferior one-fourth of the glenoid. Fourteen patients met the inclusion criteria for pseudosubluxation. The nonoperative cohort consisted of 100 females and 93 males and the operative cohort consisted of 3 males and 3 females. Total 14 children out of 199 had pseudosubluxation. Ten pseudosubluxations were seen 7 days postinjury and four were noted immediately after injury. Pseudosubluxation was seen in nine boys (64%) and five girls (36%) in the nonoperative group. Increased relative risk (RR) was associated with: fall >3 m (RR = 25.7; 95% CI, 2.7-244.0), motorized transport (RR = 11.7; 95% CI, 1.41-96.03) and sports injuries (RR = 11.0, 95% CI, 1.2-100). No statistical analysis was conducted on the operative group given the small sample. This study establishes incidence, risk factors and expected clinical course for pseudosubluxation following proximal humerus fractures. The overall incidence in the nonoperative cohort was 7.3%, radiographic evidence of pseudosubluxation resolution was available for (n = 10) patients with 100% resolution by 6 weeks. There were no readmissions or complications in the 14 patients. Pseudosubluxation occurrence was significantly increased in four mechanisms: falls >3 m, sports trauma and motor transportation. This study provides the natural history and risk factors for pseudosubluxation following proximal humerus fractures. Pseudosubluxation is more likely to occur in higher energy fracture mechanisms and will resolve without treatment. Level of Evidence: Level III, retrospective cohort.

Caffeine intake does not appear to impair tendon-to-bone healing strength in a rat rotator cuff repair model

Background

Tendon-to-bone (TtB) healing is essential for successful rotator cuff repair (RCR). This study aimed to investigate if caffeine intake impaired TtB healing in a rat RCR model.

Methods

Seventy-two rats were randomized into a caffeinated group or a noncaffeinated group. Specimens received one week of oral caffeine solution or normal saline before RCR. All rats then underwent bilateral RCR. Caffeination or saline gavages continued until rats were sacrificed at 2, 4, and 8 weeks postoperatively. Load-to-failure (primary outcomes measure), maximum stress, and stiffness of the TtB interface were measured for one shoulder of each specimen. Six random shoulders from each group underwent histological assessment of TtB healing.

Results

Load-to-failure and maximum stress of RCR did not appear to differ between groups at any time point. No difference in RCR stiffness was found between groups at 2 and 4 weeks; however, stiffness in the caffeinated group did appear to lower at 8 weeks (P = .04).

Conclusion

Perioperative caffeine intake did not appear to affect load-to-failure strength of RCR in an animal model. Although our secondary outcome measures of maximum stress and stiffness also did not appear to be influenced by perioperative caffeine intake, there did appear to be a trend toward decreased RCR stiffness at 8 weeks postoperatively in specimens that received caffeine.

Comparing complications of outpatient management of slipped capital femoral epiphysis and Blount’s disease: A database study

BACKGROUND

Currents trends in pediatric orthopaedics has seen an increase in surgeries being successfully completed in an outpatient setting. Two recent examples include slipped capital femoral epiphysis (SCFE) and Blount’s disease. Surgical indications are well-studied for each pathology, but to our knowledge, there is an absence in literature analyzing safety and efficacy of inpatient vs outpatient management of either condition. We believed there would be no increase in adverse outcomes associated with outpatient treatment of either conditions.

AIM

To investigate whether outpatient surgery for SCFE and Blount’s disease is associated with increased risk of adverse outcomes.

METHODS

The 2015-2017 American College of Surgeons National Surgical Quality Improvement Program Pediatric Registries were used to compare patient characteristics, rates of complications, and readmissions between outpatient and inpatient surgery for SCFE and Blount’s disease.

RESULTS

Total 1788 SCFE database entries were included, 30% were performed in an outpatient setting. In situ pinning was used in 98.5% of outpatient surgeries and 87.8% of inpatient surgeries (P < 0.0001). Inpatients had a greater percent of total complications than outpatients 2.57% and 1.65% respectively. Regarding Blount’s disease, outpatient surgeries constituted 41.2% of the 189 procedures included in our study. The majority of inpatients were treated with a tibial osteotomy, while the majority of outpatients had a physeal arrest (P < 0.0001). Complications were encountered in 7.4% of patients, with superficial surgical site infections and wound dehiscence being the most common. 1.6% of patients had a readmission. No differences in complication and readmission risks were found between inpatients and outpatients.

CONCLUSION

The current trend is shifting towards earlier discharges and performing procedures in an outpatient setting. This can be safely performed for a large portion of children with SCFE and Blount’s disease without increasing the risk of complications or readmissions. Osteotomies are more commonly performed in an inpatient setting where monitoring is available.

Is it necessary to fuse to the pelvis when correcting scoliosis in cerebral palsy?

BACKGROUND

Neuromuscular scoliosis is commonly associated with a large pelvic obliquity. Scoliosis in children with cerebral palsy is most commonly managed with posterior spinal instrumentation and fusion. While consensus is reached regarding the proximal starting point of fusion, controversy exists as to whether the distal level of spinal fusion should include the pelvis to correct the pelvic obliquity.

AIM

To assess the role of pelvic fusion in posterior spinal instrumentation and fusion, particularly it impact on pelvic obliquity correction, and to assess if the rate of complications differed as a function of pelvic fusion.

METHODS

This was a retrospective, cohort study in which we reviewed the medical records of children with cerebral palsy scoliosis treated with posterior instrumentation and fusion at a single institution. Minimum follow-up was six months. Patients were stratified into two groups: Those who were fused to the pelvis and those fused to L4/L5. The major outcomes were complications and radiographic parameters. The former were stratified into major and minor complications, and the latter consisted of preoperative and final Cobb angles, L5-S1 tilt and pelvic obliquity.

RESULTS

The study included 47 patients. The correction of the L5 tilt was 60% in patients fused to the pelvis and 67% in patients fused to L4/L5 (P = 0.22). The pelvic obliquity was corrected by 43% and 36% in each group, respectively (P = 0.12). Regarding complications, patients fused to the pelvis had more total complications as compared to the other group (63.0% vs 30%, respectively, P = 0.025). After adjusting for differences in radiographic parameters (lumbar curve, L5 tilt, and pelvic obliquity), these patients had a 79% increased chance of developing complications (Relative risk = 1.79; 95%CI: 1.011-3.41).

CONCLUSION

Including the pelvis in the distal level of fusion for cerebral palsy scoliosis places patients at an increased risk of postoperative complications. The added value that pelvic fusion offers in terms of correcting pelvic obliquity is not clear, as these patients had similar percent correction of their pelvic obliquity and L5 tilt compared to children whose fusion was stopped at L4/L5. Therefore, in a select patient population, spinal fusion can be stopped at the distal lumbar levels without adversely affecting the surgical outcomes.

Catching Fire: Are Operating Room Fires a Concern in Orthopedics?

OBJECTIVE

Operating room (OR) fires are considered "never events," but approximately 650 events occur annually in the United States. Our aim was to detail fires occurring during orthopedic procedures via a questionnaire because of the limited information present on this topic.

METHODS

A 25-question survey on witnessing surgical fires, hospital policies on surgical fires, and surgeons' perspective on OR fires was sent to 617 orthopedic surgeons in 18 institutions whose residency program is a member of the Collaborative Orthopaedic Educational Research Group. The response rate was 28%, with 172 surgeons having completed the survey.

RESULTS

Twelve of the 172 orthopedic surgeons surveyed reported witnessing at least 1 surgical fire in an OR setting. Electrocautery was the leading ignition source, causing fires in 7 events. A saw, laser, and light source were reported to have caused 1 fire each. Regarding fuel source for the fires, bone cement was a common culprit (n = 4), followed by gauze (n = 3). Oxygen delivery to patients was via a closed system in most cases (n = 9). No patient harm was reported in any of these cases.Just under half of the respondents (47.7%) reported not receiving any formal OR fire prevention or response training. The most common answer for frequency of concern about a surgical fire was "never" (42.4%).

CONCLUSIONS

Fires pose a risk in surgery, even in an orthopedics setting. Room oxygen can supply enough oxidizing power for a fire to occur, especially with the ubiquitous nature of ignition sources and fuels in the OR. Prevention is key with these events. Operating room personnel education must be sought, and surgeons should be mindful of the fire components in the OR.

Co-occurrence of Blount's disease and Legg-Calvé-Perthes disease: is obesity a factor?

Legg-Calvé-Perthes disease (LCPD) and Blount's disease share a similar presenting age in addition to similar symptoms such as limp or knee pain. A little overlap is mentioned about both diseases. We sought to present cases of children having both conditions to discuss the implications of this co-occurrence on diagnosis and management. After institutional review board approval, we retrospectively reviewed records of four children who developed both Blount's disease and LCPD. Patient details and outcomes were analyzed. Radiographs were evaluated for the lateral pillar classification, Stulberg classification, tibial metaphyseal-diaphyseal angle and tibiofemoral angle. Two of the cases were initially diagnosed with Blount's disease and subsequently developed Perthes, one case presented initially with both disorders and the final case had Perthes followed by Blount's. Three children were obese and one was overweight. The common symptom to all patients was an abnormal gait, which was painless in two children and painful in two. Blount's disease required surgery in three children. Radiographs showed Lateral Pillar B, B/C border and C hips, and the final Stulberg was stage II (n = 2) or stage IV (n = 2). Obesity is associated with Blount's disease and LCPD, so obese children can be at an increased risk of developing both disorders. Therefore, a child with Blount's disease who has persistent, recurrent or worsening symptoms such as gait disturbance or thigh or knee pain might benefit from a careful physical exam of the hips to prevent a delayed or even missed LCPD diagnosis.

Reliability and Validity of Visual Estimation of Femoral Head Hypoperfusion on Perfusion MRI in Legg-Calve-Perthes Disease

BACKGROUND

Assessing the severity of Legg-Calve-Perthes disease is important for treatment decision-making and determining prognosis. Perfusion magnetic resonance imaging (MRI) scans have improved our ability to assess femoral head hypoperfusion, and the use of an image analysis software called HipVasc (Scottish Rite for Children, Dallas TX) has allowed precise quantification for research purposes. In the clinical setting, using HipVasc software is not practical, and visual estimation is used to assess hypoperfusion. Currently, the reliability of visual estimation is unknown. The purpose of this study was to determine the reliability and validity of visual estimation of hypoperfusion on perfusion MRI and compare the results to measurements obtained with the HipVasc software.

METHODS

Fourteen pediatric orthopaedic surgeons, divided into 4 groups, participated in this study. Each surgeon completed a 30-minute in-person training on HipVasc before proceeding. Stratified by category of severity, 122 MRIs were randomly assigned to 1 of the 4 groups so that each group member measured the same set of ∼30 MRIs. Each surgeon documented their visual estimation of hypoperfusion first, then used HipVasc to measure the hypoperfusion and recorded their results. Interobserver reliability was assessed at the group level by calculating the intraclass correlation coefficient.

RESULTS

Good correlation and reliability was found between the visual estimate and HipVasc measurements with an overall mean intraclass correlation coefficient of 0.87 and mean Pearson coefficient of 0.90. The mean interobserver reliability of visual estimation was 0.84. Observers had a tendency to overestimate hypoperfusion with visual estimation.

CONCLUSIONS

This study demonstrates the reliability and validity of visual estimation as a clinically applicable method for determining femoral head hypoperfusion. Our study is the first to measure the reliability of visual estimation and HipVasc with a large cohort of clinicians, specifically pediatric orthopaedic surgeons with varied experience in graphical software analysis. We recommend using visual estimation as a clinically applicable method to make treatment decisions, and its accuracy is comparable to HipVasc software analysis.

LEVEL OF EVIDENCE

Level III-diagnostic.

COVID-19 Impact on Orthopedic Surgeons: Elective Procedures, Telehealth, and Income

OBJECTIVES

The purpose of this study was to investigate the response in orthopedic surgery to the coronavirus disease 2019 (COVID-19) pandemic across the United States by surveying surgeons about their care setting, timing of restrictions on elective surgery, use of telehealth, and estimated economic impact.

METHODS

A survey was distributed via REDCap through state orthopedic organizations between April and July 2020. The 22-question digital survey collected information regarding restrictions on elective procedures, location of care, utilization of telehealth, and estimated reductions in annual income.

RESULTS

In this study, 192 participants responded to the survey (average age 49.9 ± 11.0 years, 92.7% male). Responses primarily originated from Alabama (30.2%), Georgia (30.2%), and Missouri (16.1%). The remainder of the responses were grouped into the category "other." Respondents did not vary significantly by state in operative setting or income type (salary, work relative value units, or collections). Most of the participants documented elective procedure restrictions in hospital and ambulatory settings. The highest frequency of closures occurred between March 18 and 20 (47% in hospital, 51% in ambulatory). Of the participants, financial loss estimates varied across states (P = 0.005), with 50% of physicians claiming >50% losses of income in Alabama (24% Georgia, 10% Missouri, 31% other). Regarding telehealth, practices set up for these services before 2020 varied across states. None of the orthopedic practices in Alabama had telehealth before the COVID-19 pandemic (Missouri 25%, Georgia 9%, other 8%, P = 0.06); however, respondents generally were split when considering the anticipation of implementing telehealth into routine practice.

CONCLUSIONS

Most practices did implement restrictions for elective clinic visits and procedures early during the pandemic. COVID-19 ultimately will result in a large revenue loss for elective orthopedic practices. Services such as telehealth may help offset these losses and help deliver orthopedic care to patients remotely.

Blount Disease and Obstructive Sleep Apnea: An Under-recognized Association?

BACKGROUND

Obesity is strongly associated with both Blount disease and obstructive sleep apnea (OSA). Obesity increases risks for anesthetic and postoperative complications, and OSA can further exacerbate these risks. Since children with Blount disease might have both conditions, we sought to determine the perioperative complications and the prevalence of OSA among these children.

METHODS

Patients younger than 18 years undergoing corrective surgery for Blount disease were identified from 2 sources as follows: a retrospective review of records at a single institution and querying of the Kids' Inpatient Database, a nationally representative database.

RESULTS

At our institution, the prevalence of OSA among patients surgically treated for Blount disease was 23% (42/184). Blount patients were obese (100%), and predominately African American (89%), and male (68%). Patients were treated for OSA before surgery, and 2 patients (1%) had postoperative hypoxemia. In contrast, of 1059 cases of Blount disease from the Kids' Inpatient Database, 3% were diagnosed with OSA. In total, 4.4% of all the Blount children experienced complications, including hypoxemia, respiratory insufficiency, atelectasis, and arrhythmias. Complications were associated with 4.3 additional days of hospitalization (P<0.0001) and 39% additional hospital charges (P=0.002).

CONCLUSIONS

Data from the national database showed a low rate of OSA prevalence but high respiratory and OSA-associated complications, perhaps indicating that OSA may be underdiagnosed in children with Blount disease. Affected patients, especially ones with untreated OSA, sustain increased surgical morbidity. A high index of suspicion and preoperative planning helps alleviate the burden of OSA among these patients.

LEVEL OF EVIDENCE

Level III-case-control study.

Leg Compartment Syndrome Complicating Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis: A Case Report

Patient: Male, 15-year-old

Final Diagnosis: Compartment syndrome

Symptoms: Pain

Medication: —

Clinical Procedure: —

Specialty: Orthopedics and Traumatology

Combined antegrade femur lengthening and distal deformity correction: a case series

Background

Leg length discrepancy is often associated with distal femur angular deformities such as valgus or flexion. This study aims to report a new technique for simultaneous limb lengthening and acute distal femoral angular correction.

Methods

A retrospective chart review of patients undergoing a single procedure was conducted. Patients included had a single operation where they underwent distal femur osteotomy stabilized with a plate followed by antegrade nailing with a magnetically controlled intramedullary lengthening nail (PRECICE, Ellipse Technologies, Inc., Irvine, CA, USA) using a trochanteric entry.

Results

Seven femurs from 7 patients were included. The average age at operation was 13.6 years, and the leg length difference was 51 mm (range 30–105 mm). Associated deformities were valgus (4), knee flexion contracture (2), and both valgus and flexion contracture (1). Lengthening achieved was 43 mm (P = 0.0036), with a consolidation index of 27 days/cm and reliability of 0.87 (6/7). The 5 patients with angulation had an improvement of valgus from 12 to 4° (P = 0.006) and of the mechanical axis deviation from 34 to 3 mm (P = 0.0001). The range of motion also improved in the 3 patients with contractures. Preoperative gait disturbance, hip and knee pain, and functional scoliosis resolved after the limb deformities were corrected.

Conclusion

Combining a magnetic internal lengthening nail with a second distal osteotomy stabilized with a plate can successfully correct limb length and distal femur deformity acutely without altering the expected result of each procedure.

DOCK3 is a dosage-sensitive regulator of skeletal muscle and Duchenne muscular dystrophy-associated pathologies

DOCK3 is a member of the DOCK family of guanine nucleotide exchange factors that regulate cell migration, fusion and viability. Previously, we identified a dysregulated miR-486/DOCK3 signaling cascade in dystrophin-deficient muscle, which resulted in the overexpression of DOCK3; however, little is known about the role of DOCK3 in muscle. Here, we characterize the functional role of DOCK3 in normal and dystrophic skeletal muscle. Utilizing Dock3 global knockout (Dock3 KO) mice, we found that the haploinsufficiency of Dock3 in Duchenne muscular dystrophy mice improved dystrophic muscle pathologies; however, complete loss of Dock3 worsened muscle function. Adult Dock3 KO mice have impaired muscle function and Dock3 KO myoblasts are defective for myogenic differentiation. Transcriptomic analyses of Dock3 KO muscles reveal a decrease in myogenic factors and pathways involved in muscle differentiation. These studies identify DOCK3 as a novel modulator of muscle health and may yield therapeutic targets for treating dystrophic muscle symptoms.

Length unstable femoral fractures: A misnomer?

BACKGROUND

Flexible intramedullary nailing (FIMN) is relatively contraindicated for pediatric length unstable femoral fractures.

AIM

To evaluate FIMN treatment outcomes for pediatric diaphyseal length unstable femoral fractures in patients aged 5 to 13 years.

METHODS

This retrospective study includes pediatric patients (age range 5-13 years) who received operative treatment for a diaphyseal femoral fracture at a single institution between 2013 and 2019. Length unstable femur fractures treated with FIMN were compared to treatment with other fixation methods [locked intramedullary nailing (IMN), submuscular plating (SMP), and external fixation] and to length stable fractures treated with FIMN. Exclusion criteria included patients who had an underlying predisposition for fractures (e.g., pathologic fractures or osteogenesis imperfecta), polytrauma necessitating intensive care unit care and/or extensive management of other injuries, incomplete records, or no follow-up visits. Patients who had a length stable femoral fracture treated with modalities other than FIMN were excluded as well.

RESULTS

Ninety-five fractures from ninety-two patients were included in the study and consists of three groups. These three groups are length unstable fractures treated with FIMN (n = 21), length stable fractures treated with FIMN (n = 45), and length unstable fractures treated with either locked IMN, SMP, or external fixator (n = 29). P values < 0.05 were considered statistically significant. Patient characteristic differences that were statistically significant between the groups, length unstable with FIMN and length unstable with locked IMN, SMP, or external fixator, were average age (7.4 years vs 9.3 years, respectively), estimated blood loss (29.2 mL vs 98 mL, respectively) and body mass (27.8 kg vs 35.1 kg, respectively). All other patient characteristic differences were statistically insignificant. Regarding complications, length unstable with FIMN had 9 total complications while length unstable with locked IMN, SMP, or external fixator had 10. Grouping these complications into minor or major, length unstable with locked IMN, SMP, or external fixator had 6 major complication while length unstable with FIMN had 0 major complications. This difference in major complications was statistically significant. Lastly, when comparing patient characteristics between the groups, length unstable with FIMN and length stable with FIMN, all characteristics were statistically similar except time to weight bearing (39 d vs 29 d respectively). When analyzing complication differences between these two groups (9 total complications, 0 major vs 20 total complications, 4 major), the complication rates were considered statistically similar.

CONCLUSION

FIMN is effective for length unstable fractures, having a low rate of complications. FIMN is a suitable option for length stable and length unstable femur fractures alike.

The Introduction of a Preoperative MRI Protocol Significantly Reduces Unplanned Return to the Operating Room in the Treatment of Pediatric Osteoarticular Infections

BACKGROUND

Pediatric osteoarticular infection can cause severe morbidity. Some infectious loci may be difficult to identify clinically, and there may be more than one. There is little agreement regarding the appropriate use of preoperative magnetic resonance imaging (MRI) in this setting. After noting an unacceptably high rate of unplanned returns to the operating room for recurrent infection, clinicians at a tertiary care children's hospital noticed many patients had adjacent foci of infection on postoperative MRI. As a result, patients experienced prolonged treatment courses and multiple surgeries. An interdisciplinary team instituted practice guidelines whereby all patients with suspected osteoarticular infection underwent MRI for planned debridement during a reserved morning slot with a surgical suite on hold to proceed directly to surgery if indicated. Images were reviewed in real time to form the surgical plan. Young patients that required sedation for MRI were taken to surgery under the same anesthetic used for MRI without being awakened. The purpose of our retrospective study is to determine if implementing the practice guidelines for acute management of osteoarticular infection reduced unplanned returns to the operating room.

METHODS

A total of 93 patients with osteoarticular infection were included in this study. A total of 40 cases, group A, were treated before implementing practice guidelines; 53 cases, group B, were treated after implementing practice guidelines. Our primary outcomes of interest were the identification of adjacent infections prior to surgery and need for repeat surgery, either planned or unplanned.

RESULTS

Implementation of these guidelines reduced repeat surgery from 50% of patients to <27% (P=0.0099). Of patients requiring repeat surgery, 85% (n=17) were unplanned in group A versus 60% (n=9) in group B (P=0.0099). Adjacent infections were identified in 47.5% (n=19) of patients in group A, versus 60% (n=32) in group B. Adjacent infections were known before surgery in 32% (n=6) of patients in group A versus 72% (n=23) in group B. There were no statistically significant differences in initial patient characteristics or sites of infection.

CONCLUSIONS

Implementing these guidelines reduced the need for repeat surgery in this population. It is difficult to predict with sufficient accuracy which patients need preoperative MRI. While resource intensive, preoperative MRI appears to offer substantial benefit in preoperative planning.

RPL13 Variants Cause Spondyloepimetaphyseal Dysplasia with Severe Short Stature

Variants in genes encoding ribosomal proteins have thus far been associated with Diamond-Blackfan anemia, a rare inherited bone marrow failure, and isolated congenital asplenia. Here, we report one de novo missense variant and three de novo splice variants in RPL13, which encodes ribosomal protein RPL13 (also called eL13), in four unrelated individuals with a rare bone dysplasia causing severe short stature. The three splice variants (c.477+1G>T, c.477+1G>A, and c.477+2 T>C) result in partial intron retention, which leads to an 18-amino acid insertion. In contrast to observations from Diamond-Blackfan anemia, we detected no evidence of significant pre-rRNA processing disturbance in cells derived from two affected individuals. Consistently, we showed that the insertion-containing protein is stably expressed and incorporated into 60S subunits similar to the wild-type protein. Erythroid proliferation in culture and ribosome profile on sucrose gradient are modified, suggesting a change in translation dynamics. We also provide evidence that RPL13 is present at high levels in chondrocytes and osteoblasts in mouse growth plates. Taken together, we show that the identified RPL13 variants cause a human ribosomopathy defined by a rare skeletal dysplasia, and we highlight the role of this ribosomal protein in bone development.

Risk Factors for Readmission After Surgical Treatment of Slipped Capital Femoral Epiphysis

Slipped capital femoral epiphysis (SCFE) is a common, surgically treated adolescent hip condition. This study sought to evaluate postoperative complications and factors associated with hospital readmission using a nationally representative database. The 2013 Healthcare Cost and Utilization Project's Nationwide Readmissions Database was queried to analyze the incidence of acute readmission and complications for all patients with SCFE. Patients were separated based on 3 different operative approaches (open procedures, closed procedures, or both) and were compared based on choice of procedure, clinical characteristics, patient demographics, comorbidities, and complications. Univariate and multivariate techniques were used to predict readmission and complications. A total of 1082 patients with SCFE were identified; 58 (5.9%) were readmitted within 90 days of the index surgery, and 47 (73.4%) underwent a "closed" surgery, including 18 bilateral (27.4%). Increasing age and shorter primary length of stay were protective against readmission. Patients with the comorbidity of hypothyroidism were 47.4 times more likely to be readmitted. Obesity, sex, and median household income were not predictive of readmission. Patients readmitted were more likely to have undergone an index procedure of closed reduction or both an open and closed reduction procedure. This study is the first to report national SCFE readmission and complication rates and allows pediatric orthopedic surgeons to have a better understanding of associated risk factors. [Orthopedics. 2019; 42(6):e507-e513.].

Do We Need Postoperative Chest Radiographs After Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis?

STUDY DESIGN

The question was addressed in three ways: (1) a query of Kids' Inpatient Database (KID) to obtain nationally representative data; (2) retrospective review of cases at a single institution; (3) survey of Scoliosis Research Society (SRS) spine surgeons.

OBJECTIVES

Evaluate the rate of immediate postoperative pulmonary complications, risk factors, and relevant surgeon practice patterns, to determine the usefulness of routine postoperative chest radiographs after posterior spinal instrumentation and fusion (PSIF) for adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

Routine postoperative chest radiography after PSIF for AIS is performed in many institutions to evaluate for acute pulmonary complications, particularly pneumothorax (PTX). The incidence of pneumothorax and its effect on management is unknown.

METHODS

The frequency of PTX and surgical intervention were recorded. We evaluated associations between PTX and patient demographics or comorbidities, as well as survey respondent demographics and their practice patterns.

RESULTS

In the KID data sets, the risk of PTX after PSIF for AIS patients was 0.3% (30/9,036), with intervention required in 13.3% (4/30) of PTX-positive patients (0.04% of all cases). Review of cases at our institution revealed a PTX rate of 3.3% (8/244) by radiology report. No surgical intervention was required. Patients with PTX had, on average, an increased number of vertebrae fused (p = .012), a proximal thoracic scoliosis curve location (p = .009), and/or an intraoperative blood transfusion (p = .002). SRS respondents reported a PTX risk of 0.8% (87/11,318), and 32.2% (89/276) of respondents indicated routine use of postoperative chest radiographs. Of those, 46.1% (41/89) specified willingness to change practice patterns if provided evidence of low PTX rates.

CONCLUSIONS

Pneumothorax is uncommon after PSIF for AIS. The need for intervention is even less common. Routine postoperative chest radiographs are of questionable value after PSIF for AIS.

LEVEL OF EVIDENCE

Level III.

Psychomotor Testing for Orthopedic Residency Applicants: A Pilot Study

OBJECTIVE

The purpose of this study was to develop an objective motor skills testing system to aid in the evaluation of potential orthopedic residents.

DESIGN

Participants attempted a battery of 5 motor skills tests (4 novel tests and the Grooved Pegboard [GPT] Test) in one 10-minute session. A percentile-based scoring system was created for each test based on raw scores. One-way analysis of variance was used to compare testing scores among 3 cohorts. Each novel test and overall scores were compared with GPT scores as a relative measure of validity.

SETTING

The 2015 orthopedic surgery residency interview season at an academic institution.

PARTICIPANTS

Thirty orthopedic residents and 72 nonresidents (15 community volunteers and 57 orthopedic surgery residency applicants).

RESULTS

Overall, residents performed better than nonresidents (p < 0.0001) and applicants performed worse than residents or volunteers (p < 0.0001). There were positive correlations between the GPT score and overall battery score (r = 0.63), screw and nut test (r = 0.40), and mimic a structure test (r = 0.26). The fracture reduction test and drilling test scores did not correlate to performance on the GPT.

CONCLUSIONS

Psychomotor testing for surgical applicants is an area in need of study. This investigation successfully piloted a novel battery of tests, which is easily reproducible and thus may be feasible for use in the orthopedic surgery residency interview setting. Longitudinal evaluation is required to explore correlation with future operative skill.

Immature myeloid cells are critical for enhancing bone fracture healing through angiogenic cascade

Bone fractures heal with overlapping phases of inflammation, cell proliferation, and bone remodeling. Osteogenesis and angiogenesis work in concert to control many stages of this process, and when one is impaired it leads to failure of bone healing, termed a nonunion. During fracture repair, there is an infiltration of immune cells at the fracture site that not only mediate the inflammatory responses, but we hypothesize they also exert influence on neovasculature. Thus, further understanding the effects of immune cell participation throughout fracture healing will reveal additional knowledge as to why some fractures heal while others form nonunions, and lead to development of novel therapeutics modulating immune cells, to increase fracture healing and prevent nonunions. Using novel femoral segmental and critical-size defect models in mice, we identified a systemic and significant increase in immature myeloid cell (IMC) infiltration during the initial phase of fracture healing until boney union is complete. Using gemcitabine to specifically ablate the IMC population, we confirmed delayed bone healing. Further, adoptive transfer of IMC increased bone growth in a nonunion model, signifying the role of this unique cell population in fracture healing. We also identified IMC post-fracture have the ability to increase endothelial cell migration, and tube formation, signaling the essential communication between the immune system and angiogenesis as a requirement for proper bone healing. Based on this data we propose that IMC may play a significant role in fracture healing and therapeutic targeting of IMC after fracture would minimize the chances of eventual nonunion pathology.

A bio-inspired hybrid nanosack for graft vascularization at the omentum

For three-dimensional tissue engineering scaffolds, the major challenges of hydrogels are poor mechanical integrity and difficulty in handling during implantation. In contrast, electrospun scaffolds provide tunable mechanical properties and high porosity; but, are limited in cell encapsulation. To overcome these limitations, we developed a "hybrid nanosack" by combination of a peptide amphiphile (PA) nanomatrix gel and an electrospun poly (ε-caprolactone) (ePCL) nanofiber sheet with porous crater-like structures. This hybrid nanosack design synergistically possessed the characteristics of both approaches. In this study, the hybrid nanosack was applied to enhance local angiogenesis in the omentum, which is required of tissue engineering scaffolds for graft survival. The ePCL sheet with porous crater-like structures improved cell and blood vessel penetration through the hybrid nanosack. The hybrid nanosack also provided multi-stage fibroblast growth factor-2 (FGF-2) release kinetics for stimulating local angiogenesis. The hybrid nanosack was implanted into rat omentum for 14days and vascularization was analyzed by micro-CT and immunohistochemistry; the data clearly demonstrated that both FGF-2 delivery and porous crater-like structures work synergistically to enhance blood vessel formation within the hybrid nanosack. Therefore, the hybrid nanosack will provide a new strategy for engineering scaffolds to achieve graft survival in the omentum by stimulating local vascularization, thus overcoming the limitations of current strategies.

STATEMENT OF SIGNIFICANCE

For three-dimensional tissue engineering scaffolds, the major challenges of hydrogels are poor mechanical integrity and difficulty in handling during implantation. In contrast, electrospun scaffolds provide tunable mechanical properties and high porosity; but, are limited in cell encapsulation. To overcome these limitations, we developed a "hybrid nanosack" by combination of a peptide amphiphile (PA) nanomatrix gel and an electrospun poly (ε-caprolactone) (ePCL) nanofiber sheet with porous crater-like structures. This design synergistically possessed the characteristics of both approaches. In this study, the hybrid nanosack was applied to enhance local angiogenesis in the omentum, which is required of tissue engineering scaffolds for graft survival. The hybrid nanosack was implanted into rat omentum for 14days and vascularization was analyzed by micro-CT and immunohistochemistry. We demonstrate that both FGF-2 delivery and porous crater-like structures work synergistically to enhance blood vessel formation within the hybrid nanosack. Therefore, the hybrid nanosack will provide a new strategy for engineering scaffolds to achieve graft survival in the omentum by stimulating local vascularization, thus overcoming the limitations of current strategies.

Avascular Necrosis of Trochlea After Supracondylar Humerus Fractures in Children

Avascular necrosis (AVN) is a rare but important complication after supracondylar humerus fractures. Posttraumatic humerus deformity was first reported in 1948 and sporadically thereafter. AVN deformity has been classified as type A (AVN of the lateral ossification center) and type B (AVN of the entire medial crista and a metaphyseal portion). In this article, we present 5 cases of AVN after supracondylar humerus fracture, discuss the importance of late clinical findings, and postulate a mechanism of AVN in nondisplaced fractures. Five cases of AVN after supracondylar humerus fracture were reviewed from the Children's of Alabama database. Four of the 5 patients were female. Four patients sustained a Gartland type III fracture, and 1 patient sustained a nondisplaced Gartland type I fracture. Age at time of injury ranged from 5 years to 10 years. All patients had an asymptomatic clinical period after treatment and re-presented 6 months to 7 years later with elbow pain or loss of motion. All patients were treated symptomatically. AVN of the trochlea has a late clinical presentation. The cause of this complication is interruption of the trochlea blood supply. In displaced fractures, the medial and/or lateral vessels are injured, leading to type A or type B deformity. In nondisplaced fractures, the lateral vessels are interrupted by tamponade because of encased fracture hematoma; this presents as a type A deformity. Both type A and type B deformities can be clinically significant. AVN of the trochlea should be considered in patients with late presentation of pain or loss of motion after treatment of supracondylar humerus fractures.

BMI and magnitude of scoliosis at presentation to a specialty clinic

OBJECTIVE

To determine whether curve magnitude of scoliosis at presentation correlates with BMI.

METHODS

Retrospective chart review of 180 patients presenting with scoliosis was performed. Curve pattern and magnitude, Risser status, occurrence of surgery, zip code, height and weight, race, and insurance status were recorded. Relationships were examined by Spearman rank and Pearson correlations, and logistic regression analysis was used to determine odds ratios.

RESULTS

For both thoracic and lumbar curve patterns, there was a correlation between BMI and curve magnitude. Spearman rank correlation was 0.19 for thoracic (P = .03) and 0.24 for lumbar curves (P = .02). Overweight or obese patients were not more likely, however, to present with curves at higher risk of progression or more likely to have surgical intervention. With respect to potential confounding socioeconomic variables, thoracic curve magnitude was negatively correlated with median family income (Spearman rank correlation -0.17, P = .04). Curve magnitude was not correlated with race, distance, or insurance payer.

CONCLUSIONS

Patients with high BMI and scoliosis are more likely to present with larger curves, but not more likely to require surgery. This is concerning because of the national trend of increasing childhood obesity and because scoliosis treatment may be more complicated in larger curves. Socioeconomic factors may also be barriers to access.

The Use of Chewing Gum Postoperatively in Pediatric Scoliosis Patients Facilitates an Earlier Return to Normal Bowel Function

PURPOSE

In surgical correction of scoliosis in pediatric patients, gastrointestinal complications including postoperative ileus can result in extended hospital stays, poorer pain management, slower progression with physical therapy, and overall decreased patient satisfaction. In patients undergoing gastrointestinal, gynecological, and urological surgery, gum chewing has been shown to reduce time to flatus and passage of feces. The authors hypothesized that chewing gum could also speed return to normal bowel function in pediatric patients undergoing surgical correction of scoliosis.

METHODS

The researchers obtained institutional review board approval for a prospective, randomized, controlled trial. Eligible patients included all adolescent idiopathic scoliosis patients undergoing posterior spinal fusion. Exclusion criteria included previous gastrointestinal surgery or preexisting gastrointestinal disease. Patients were randomized by coin flip. The treatment group chewed sugar-free bubble gum 5 times a day for 20 to 30 minutes beginning on postoperative day 1; the control group did not chew gum. Patients were asked a series of questions regarding subjective gastrointestinal symptoms each day. Time to flatus and first passage of feces were recorded as indicators of return to normal bowel function. Normality of data was assessed using normal probability plots.

RESULTS

A total of 83 patients completed the study (69 females and 14 males; mean age, 14.4 years). Of the 42 patients in the chewing gum group, 8 elected to stop chewing gum regularly before discharge for to a variety of reasons. Patients who chewed gum experienced first bowel movement on average 145.9 hours after surgery, 30.9 hours before those who did not chew gum (p = .04). Gum-chewing patients first experienced flatus an average of 55.2 hours after surgery, compared with 62.3 hours for controls. This trend did not reach statistical significance (p = .12). No difference was noted in duration of hospital stay, medications administered as required, or subjective symptoms.

CONCLUSION

Chewing gum after posterior spinal fusion for scoliosis is safe and may speed return of normal bowel function. Chewing gum after surgical correction of scoliosis facilitates an earlier return to normal bowel function, which may improve patient satisfaction in the early postoperative period.

Contaminated open fracture and crush injury: a murine model

Modern warfare has caused a large number of severe extremity injuries, many of which become infected. In more recent conflicts, a pattern of co-infection with Acinetobacter baumannii and methicillin-resistant Staphylococcus aureus has emerged. We attempted to recreate this pattern in an animal model to evaluate the role of vascularity in contaminated open fractures. Historically, it has been observed that infected bones frequently appear hypovascular, but vascularity in association with bone infection has not been examined in animal models. Adult rats underwent femur fracture and muscle crush injury followed by stabilization and bacterial contamination with A. baumannii complex and methicillin-resistant Staphylococcus aureus. Vascularity and perfusion were assessed by microCT angiography and SPECT scanning, respectively, at 1, 2 and 4 weeks after injury. Quantitative bacterial cultures were also obtained. Multi-bacterial infections were successfully created, with methicillin-resistant S. aureus predominating. There was overall increase in blood flow to injured limbs that was markedly greater in bacteria-inoculated limbs. Vessel volume was greater in the infected group. Quadriceps atrophy was seen in both groups, but was greater in the infected group. In this animal model, infected open fractures had greater perfusion and vascularity than non-infected limbs.

An evaluation of carrier agents for desferoxamine, an up-regulator of vascular endothelial growth factor

Avascularity and hypoxia result in avascular necrosis and play a negative role in fracture healing. The FDA-approved iron chelating agent, desferoxamine (DFO) in a liquid form, has been shown to induce angiogenesis and improve fracture healing through upregulation of the vascular endothelial growth factor. We were concerned that local injection of DFO would either fail to adequately deliver sufficient drug to the desired site or lead to undesired delivery to adjacent sites. Therefore, a sustained release delivery system was desirable to direct DFO to the intended site. Calcium sulfate pellets, collagen sponges, and demineralized cortical bone matrix were all evaluated as potentially controlled release systems for DFO using a fetal mouse metatarsal angiogenesis assay. Angiogenesis was analyzed using a vascularity grading scale, by measuring the mean vessel length of the 5 longest vessels, and by counting the mean number of vessels per metatarsal. Although there was some evidence of angiogenesis with all three carriers, DFO loaded CaSO4 pellets increased vascularity grading, the mean length of the five longest vessels, and the mean number of vessels, all by statistically significant margins versus the control. These results suggest that CaSO4 pellets could be used as a viable, nontoxic, controlled release system for DFO in clinical situations where increased angiogenesis and bone growth are desirable.

Biphasic peptide amphiphile nanomatrix embedded with hydroxyapatite nanoparticles for stimulated osteoinductive response

Formation of the native bone extracellular matrix (ECM) provides an attractive template for bone tissue engineering. The structural support and biological complexity of bone ECM are provided within a composite microenvironment that consists of an organic fibrous network reinforced by inorganic hydroxyapatite (HA) nanoparticles. Recreating this biphasic assembly, a bone ECM analogous scaffold comprising self-assembling peptide amphiphile (PA) nanofibers and interspersed HA nanoparticles was investigated. PAs were endowed with biomolecular ligand signaling using a synthetically inscribed peptide sequence (i.e., RGDS) and integrated with HA nanoparticles to form a biphasic nanomatrix hydrogel. It was hypothesized the biphasic hydrogel would induce osteogenic differentiation of human mesenchymal stem cells (hMSCs) and improve bone healing as mediated by RGDS ligand signaling within PA nanofibers and embedded HA mineralization source. Viscoelastic stability of the biphasic PA hydrogels was evaluated with different weight concentrations of HA for improved gelation. After demonstrating initial viability, long-term cellularity and osteoinduction of encapsulated hMSCs in different PA hydrogels were studied in vitro. Temporal progression of osteogenic maturation was assessed by gene expression of key markers. A preliminary animal study demonstrated bone healing capacity of the biphasic PA nanomatrix under physiological conditions using a critical size femoral defect rat model. The combination of RGDS ligand signaling and HA nanoparticles within the biphasic PA nanomatrix hydrogel demonstrated the most effective osteoinduction and comparative bone healing response. Therefore, the biphasic PA nanomatrix establishes a well-organized scaffold with increased similarity to natural bone ECM with the prospect for improved bone tissue regeneration.

Discovery of a new molecular probe ML228: an activator of the hypoxia inducible factor (HIF) pathway

Hypoxia and ischemia are linked to several serious public health problems that affect most major organ systems. Specific examples include diseases of the cardiovascular, pulmonary, renal, neurologic, and musculoskeletal systems. The most significant pathway for cellular response to hypoxia is the hypoxia inducible factor (HIF) pathway. HIFs are transcription factors responsible for the activation of genes which encode proteins that mediate adaptive responses to reduced oxygen availability. A high-throughput cell-based HIF-mediated gene reporter screen was carried out using the NIH's Molecular Libraries Small Molecule Repository to identify activators of the HIF pathway. This communication describes the subsequent medicinal chemistry optimization of a triazine scaffold that led to the identification of the new molecular probe ML228. A discussion of HIF activation SAR within this chemotype as well as detailed in vitro characterization of the probe molecule is presented here.

Role of HIF-1alpha in skeletal development

Angiogenesis and osteogenesis are tightly coupled during bone development and regeneration. Mesenchymal cells in the developing stroma elicit angiogenic signals to recruit new blood vessels into bone. Reciprocal signals, likely emanating from the incoming vascular endothelium, stimulate mesenchymal cell specification through additional interactions with cells within the vascular stem cell niche. The hypoxia-inducible factor-1 alpha (HIF-1) pathway has been identified as a key component in this process. We demonstrated that overexpression of HIF-1 in mature osteoblasts through disruption of the von Hippel-Lindau protein profoundly increases angiogenesis and osteogenesis; these processes appear to be coupled by cell nonautonomous mechanisms involving the action of vascular endothelial growth factor (VEGF) on the endothelial cells. The same occurred in the model of injury-mediated bone regeneration (distraction osteogenesis). Surprisingly, manipulation of HIF-1 does not influence angiogenesis of the skull bones, where earlier activation of HIF-1 in the condensing mesenchyme upregulates osterix during cranial bone formation.

Prolyl hydroxylase inhibitors increase neoangiogenesis and callus formation following femur fracture in mice

Skeletal trauma and impaired skeletal healing is commonly associated with diminished vascularity. Hypoxia inducible factor alpha (HIF-1) is a key transcription factor responsible for activating angiogenic factors during development and tissue repair. Small molecule inhibitors of the prolyl hydroxylase enzyme (PHD), the key enzyme responsible for degrading HIF-1, have been shown to activate HIF-1, and are effective in inducing angiogenesis. Here we examined the effects of several commercially available PHD inhibitors on bone marrow mesenchymal stromal cells (MSCs) in vitro and in a stabilized fracture model in vivo. Three PHD inhibitors [Desferrioxamine (DFO), L-mimosine (L-mim), and Dimethyloxalylglycine (DMOG)] effectively activated a HIF-1 target reporter, induced expression of vascular endothelial growth factor (VEGF) mRNA in vitro, and increased capillary sprouting in a functional angiogenesis assay. DFO and DMOG were applied by direct injection at the fracture site in a stabilized murine femur fracture model. PHD inhibition increased the vascularity at 14 days and increased callus size as assessed by microCT at 28 days. These results suggest that HIF activation is a viable approach to increase vascularity and bone formation following skeletal trauma.

Hypoxia and HIF-1alpha expression in the epiphyseal cartilage following ischemic injury to the immature femoral head

HIF-1alpha has been shown to be a central mediator of cellular response to hypoxia. The role it plays after ischemic injury to the immature femoral head is unknown. The purpose of this study was to determine the region of the femoral head affected by hypoxia following ischemic injury to the immature femoral head and to determine the site of HIF-1alpha activation and revascularization. We hypothesize that the epiphyseal cartilage, rather than the bony epiphysis, is the site of HIF-1alpha activation following ischemic osteonecrosis and that the epiphyseal cartilage plays an important role in the revascularization process.

MATERIALS AND METHODS

Femoral head osteonecrosis was surgically induced in 56 immature pigs. Hypoxyprobe staining, cell viability assay, HIF-1alpha western blot, RT-qPCR of HIF-1alpha, VEGF, VEGFR2, and PECAM, and micro-CT assessments of microfil-infused femoral heads were performed.

RESULTS

Severe hypoxia was present in the bony epiphysis and the lower part of the epiphyseal cartilage following ischemia. In the bony epiphysis, extensive cell death and tissue necrosis was observed with degradation of proteins and RNAs which precluded further analysis. In the epiphyseal cartilage, the loss of cell viability was limited to its deep layer with the remainder of the cartilage remaining viable. Furthermore, the cartilage from the ischemic side showed a significant increase in HIF-1alpha protein level and HIF-1alpha expression. VEGF expression in the cartilage was dramatically and significantly increased at 24 h, 2 and 4 weeks (p<0.05 for all) with 5 to 10 fold increase being observed on the ischemic side compared to the normal side. PECAM and VEGFR2 expressions in the cartilage were both significantly decreased at 24 h but returned to the normal levels by 2 and 4 weeks, respectively. Micro-CT showed revascularization of the cartilage on the ischemic side with the vessel volume/total volume equaling the normal side by 4 weeks.

CONCLUSIONS

Acute ischemic injury to the immature femoral head induced severe hypoxia and cell death in the bony epiphysis and the deep layer of the epiphyseal cartilage. Viable chondrocytes in the superficial layer of the epiphyseal cartilage showed HIF-1alpha activation and VEGF upregulation with subsequent revascularization occurring in the cartilage.

Oxygen sensing and osteogenesis

Osteogenesis and angiogenesis are tightly coupled during bone formation and repair. Blood vessels not only carry oxygen and nutrients to the developing bone, but also play an active role in bone formation and remodeling by mediating the interaction between osteoblasts, osteocytes, osteoclasts, and vascular cells at a variety of levels. Tissue hypoxia is believed to be a major stimulus for angiogenesis by activating hypoxia-inducible factor alpha (HIFalpha) pathway, which is a central regulator of hypoxia adaptation in vertebrates. HIFalpha remains inactive under normoxic conditions through pVHL-mediated polyubiquitination and proteasomal degradation. Activation of the HIFalpha pathway by hypoxia triggers hypoxia-responsive gene expression, such as vascular endothelial growth factor (Vegf), which plays a critical role in angiogenesis, endochondral bone formation, and bone repair following fracture. Recent work from our laboratory has shown that osteoblasts use the HIFalpha pathway to sense reduced oxygen tension and transmit signals that impinge on angiogenic and osteogenic gene programs during bone formation. Using a genetic approach, we have demonstrated that overexpression of HIFalpha in mouse osteoblasts through disruption of Vhl results in profound increases in angiogenesis and osteogenesis, which appear to be mediated by cell nonautonomous mechanisms involving VEGF. These studies suggest that VEGF exerts many of its actions on bone indirectly by stimulation of angiogenesis. Whether or to what extent this angiogenic factor functions independent of endothelial cells remains to be determined.

The hypoxia-inducible factor alpha pathway couples angiogenesis to osteogenesis during skeletal development

Skeletal development and turnover occur in close spatial and temporal association with angiogenesis. Osteoblasts are ideally situated in bone to sense oxygen tension and respond to hypoxia by activating the hypoxia-inducible factor alpha (HIF alpha) pathway. Here we provide evidence that HIF alpha promotes angiogenesis and osteogenesis by elevating VEGF levels in osteoblasts. Mice overexpressing HIF alpha in osteoblasts through selective deletion of the von Hippel-Lindau gene (Vhl) expressed high levels of Vegf and developed extremely dense, heavily vascularized long bones. By contrast, mice lacking Hif1a in osteoblasts had the reverse skeletal phenotype of that of the Vhl mutants: long bones were significantly thinner and less vascularized than those of controls. Loss of Vhl in osteoblasts increased endothelial sprouting from the embryonic metatarsals in vitro but had little effect on osteoblast function in the absence of blood vessels. Mice lacking both Vhl and Hif1a had a bone phenotype intermediate between those of the single mutants, suggesting overlapping functions of HIFs in bone. These studies suggest that activation of the HIF alpha pathway in developing bone increases bone modeling events through cell-nonautonomous mechanisms to coordinate the timing, direction, and degree of new blood vessel formation in bone.

Altered skeletal maturation in moderate to severe cerebral palsy

Abnormalities of growth and development are prevalent in children with cerebral palsy (CP). The purpose of this study was to assess skeletal maturation ('bone age') in this population and to identify those factors related to alterations in this aspect of development. The study group was a convenience sample of 80 participants (47 males, 33 females; age range 2 y 6 mo to 21 y 1 mo; mean age 10 y 10 mo, SD 4 y 2 mo). All had moderate to severe spastic or mixed spastic CP at Gross Motor Function Classification System level III (n=8, 10%); level IV (n=21, 26%); or level V (n=51, 64%). Skeletal maturation was assessed by the detailed Fels method of scoring hand-wrist radiographs. Each evaluation included clinical and anthropometric assessments, Tanner staging, bone density measurements, and the Children's Health Status Questionnaire. Follow-up evaluations were obtained for 41 participants, providing a total of 143 evaluations. Median interval between first and last evaluations was 24.7 months (range 11.9 to 45mo). For the study group as a whole there was no significant difference between a child's skeletal age and chronological age. However, there was a high prevalence of individual participants in whom skeletal age was advanced (7%) or delayed (10%), relative to chronological age, by more than 2 years. In multivariant analyses it was found that diminished linear growth (height), low lumbar-spine bone density, and low body fat as measured by triceps skinfolds were all independently associated with delays in skeletal maturation. Multiple aspects of skeletal growth and development, including skeletal maturation, are frequently altered in children with moderate to severe CP.

Skeletal maturation in children with quadriplegic cerebral palsy

Skeletal growth abnormalities, including diminished linear growth and osteoporosis, are well recognized in children with severe cerebral palsy (CP). The purpose of this study was to examine skeletal bone age, another aspect of skeletal growth, in this severely handicapped population. The study consisted of two parts, each assessing skeletal maturation but using different methods on different cohorts of children with CP: 133 hand-wrist radiographs were scored using the Fels method and 241 pelvis radiographs were scored using the Oxford method. The Oxford method has not been validated against contemporary normal children; therefore, 114 recently obtained pelvis radiographs of otherwise normal children being evaluated for trauma were included as controls. On average, there was not a statistically significant difference between the chronological age of the child with CP and the skeletal age based on hand-wrist x-rays. Similarly, average pelvic skeletal maturity scores did not differ between the CP children and age-matched contemporary controls. While averages did not differ, wide individual variation was noted in the CP cohorts, with a high prevalence of both delayed and advanced skeletal maturity. Of note, pelvic maturity scores in the contemporary controls significantly differed from those reported in the original Oxford series from over 50 years ago.

Primary synovial osteochondromatosis of the hip: report of two cases with long-term follow-up after synovectomy and a review of the literature

Primary synovial osteochondromatosis of the hip joint is rare. Two cases treated successfully by open synovectomy of the hip joint and removal of loose bodies, with a follow-up of 7 years in one case and 5 years in the other, are described. A review of all published case reports in the English language suggests that an open synovectomy of the hip will relieve pain and may prevent or delay the progression of degenerative changes.

The relationship between alveolar macrophage TNF, IL-1, and PGE2 release, alveolitis, and disease severity in sarcoidosis

A mononuclear cell alveolitis, comprised in part of activated macrophages, is thought to precede granuloma formation and fibrosis in pulmonary sarcoidosis. Tumor necrosis factor-alpha (TNF), interleukin 1-beta (IL-1), and prostaglandin E2 (PGE2) are potent mediators released by activated alveolar macrophages. To determine if alveolar macrophage TNF, IL-1, and PGE2 release was associated with clinically progressive pulmonary sarcoidosis, we obtained alveolar macrophages from bronchoalveolar lavage of 68 patients with biopsy specimen-confirmed sarcoidosis, cultured the macrophages in the presence and absence of lipopolysaccharide (10 mg/L) for 24 h, and measured TNF (enzyme-linked immunosorbent assay), IL-1 (enzyme-linked immunosorbent assay), and PGE2 (radioimmunoassay) release. Alveolar macrophages from most patients with sarcoidosis spontaneously released TNF, IL-1, and PGE2. The amounts of these mediators released (either spontaneously or following lipopolysaccharide stimulation) did not positively correlate with the numbers of any of the cells in bronchoalveolar lavage fluid, the clinical status of disease (stable vs deterioration), steroid usage, or cigarette smoking. The relative release of each of the individual mediators, however, was highly correlated with the release of the other mediators. The studies suggest that these markers of alveolar macrophage activation from a single bronchoalveolar lavage are poor indicators of clinically progressive disease.

Outcome of subjects with idiopathic pulmonary fibrosis who fail corticosteroid therapy. Implications for further studies

To evaluate the outcome of subjects with idiopathic pulmonary fibrosis (IPF) whose conditions clinically deteriorate while receiving corticosteroid therapy, we studied 12 of these subjects (7 male, 5 female) who received subsequent therapy with intravenous (IV) pulse cyclophosphamide (CPX). Seven of the 12 study subjects died during the course of therapy. Six of these subjects died of respiratory failure, and one died of cholecystitis. Among those who died, the mean age at diagnosis was 63 years compared with 57 years in those who have continued to survive (p = 0.29). Smoking status and pack-years of cigarette smoking were similar between those subjects who died and those who continue to survive. However, subjects who died received CPX for a mean of 6 months, while subjects still living have received CPX for a mean of 16 months (p = 0.01). Subjects who died were given a CPX a mean of 64 months after the onset of symptoms, compared with a mean of 50 months for subjects who are still alive (p = 0.57). Interestingly, there were no significant differences in measures of pulmonary function between living and dead subjects. In fact, measures of lung function and gas exchange remained stable in both groups throughout the period of observation. These data suggest that (1) measures of lung function may not be a reliable indicator of patient mortality in end-stage IPF, and (2) while not statistically significant, these data raise the possibility that duration of symptomatic disease may play a role in the outcome of IPF patients receiving alternative therapeutic agents after failure of corticosteroid therapy. In future intervention trails, controlling entry criteria for duration of disease may prove helpful in determining the effects of these agents on the disease process. These data do not permit a determination of the effect of CPX in patients with IPF.

The influence of cigarette smoking on lung function in patients with idiopathic pulmonary fibrosis

The purpose of this investigation was to quantify the effect of cigarette smoking on standard measures of lung function in patients with idiopathic pulmonary fibrosis (IPF). Our study population consisted of 73 patients in whom IPF had been clinically diagnosed; in 67% the diagnosis was confirmed by open lung biopsy. The average age was 63 yr; 62% were men, and 70% were either former or current cigarette smokers. Current cigarette smokers were found to have a greater percent predicted residual volume. Interestingly, in a univariate analysis, pack-years of cigarette smoking was found to be directly associated with increased measures of lung volumes (TLC, FRC, and RV) and diminished gas exchange (DLCO). Linear multivariate regression models demonstrated that current cigarette smokers have greater measures of RV and FRC and that increasing pack-years of cigarette smoking is associated with diminished gas exchange. Importantly, the FEV/FVC ratio was not significantly related to either smoking status or pack-years of cigarette smoking. Results from our study indicated that among patients with IPF, current cigarette smokers will tend to trap air (higher RV and FRC), and that cigarette smoking appears to adversely alter gas exchange. Moreover, IPF appears to reduce the likelihood of developing physiologic correlates of airflow obstruction among cigarette smokers. However, this does not imply that IPF prevents the development of cigarette-induced lung disease. In fact, the association between cigarette smoking and both increased lung volumes and diminished gas exchange suggests the presence of both emphysema and interstitial fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Localization of adrenal and extra-adrenal pheochromocytomas by magnetic resonance imaging

We found magnetic resonance imaging helpful in the localization of both an adrenal and an extra-adrenal pheochromocytoma, since these tumors produced a high-intensity "light bulb" image. MRI is an excellent method for localizing pheochromocytomas because it detects adrenal and extra-adrenal pheochromocytomas missed by computerized tomography and adrenal-renal ultrasonography, and because the high-intensity MRI signal generated by pheochromocytomas is useful in differentiating them from nonfunctioning adrenal masses in hypertensive patients.

Appendicitis in children

Six hundred and fifty-one patients with appendicitis were reviewed and an over-all perforation rate of 36.5 per cent accompanied by a major complication rate of only 3.38 per cent and an over-all complication rate of 9.06 per cent was reported. This low complication rate despite a high level of perforation can be attributed to the use of antibiotic regimens effective against both aerobic and anaerobic organisms. A thorough irrigation and flushing of debris and exudate from the abdominal cavity of patients with ruptured appendicitis may improve these rates.