Effects of static exercises on hip muscle fatigue and knee wobble assessed by surface electromyography and inertial measurement unit data.

Hip muscle weakness can be a precursor to or a result of lower limb injuries. Assessment of hip muscle strength and muscle motor fatigue in the clinic is important for diagnosing and treating hip-related impairments. Muscle motor fatigue can be assessed with surface electromyography (sEMG), however sEMG requires specialized equipment and training. Inertial measurement units (IMUs) are wearable devices used to measure human motion, yet it remains unclear if they can be used as a low-cost alternative method to measure hip muscle fatigue. The goals of this work were to (1) identify which of five pre-selected exercises most consistently and effectively elicited muscle fatigue in the gluteus maximus, gluteus medius, and rectus femoris muscles and (2) determine the relationship between muscle fatigue using sEMG sensors and knee wobble using an IMU device. This work suggests that a wall sit and single leg knee raise activity fatigue the gluteus medius, gluteus maximus, and rectus femoris muscles most reliably (p < 0.05) and that the gluteus medius and gluteus maximus muscles were fatigued to a greater extent than the rectus femoris (p = 0.031 and p = 0.0023, respectively). Additionally, while acceleration data from a single IMU placed on the knee suggested that more knee wobble may be an indicator of muscle fatigue, this single IMU is not capable of reliably assessing fatigue level. These results suggest the wall sit activity could be used as simple, static exercise to elicit hip muscle fatigue in the clinic, and that assessment of knee wobble in addition to other IMU measures could potentially be used to infer muscle fatigue under controlled conditions. Future work examining the relationship between IMU data, muscle fatigue, and multi-limb dynamics should be explored to develop an accessible, low-cost, fast and standardized method to measure fatiguability of the hip muscles in the clinic.

Exome sequencing of 1190 non-syndromic clubfoot cases reveals HOXD12 as a novel disease gene.

BACKGROUND: Clubfoot, presenting as a rigid inward and downward turning of the foot, is one of the most common congenital musculoskeletal anomalies. The aetiology of clubfoot is poorly understood and variants in known clubfoot disease genes account for only a small portion of the heritability. METHODS: Exome sequence data were generated from 1190 non-syndromic clubfoot cases and their family members from multiple ethnicities. Ultra-rare variant burden analysis was performed comparing 857 unrelated clubfoot cases with European ancestry with two independent ethnicity-matched control groups (1043 in-house and 56 885 gnomAD controls). Additional variants in prioritised genes were identified in a larger cohort, including probands with non-European ancestry. Segregation analysis was performed in multiplex families when available. RESULTS: Rare variants in 29 genes were enriched in clubfoot cases, including PITX1 (a known clubfoot disease gene), HOXD12, COL12A1, COL9A3 and LMX1B. In addition, rare variants in posterior HOX genes (HOX9-13) were enriched overall in clubfoot cases. In total, variants in these genes were present in 8.4% (100/1190) of clubfoot cases with both European and non-European ancestry. Among these, 3 are de novo and 22 show variable penetrance, including 4 HOXD12 variants that segregate with clubfoot. CONCLUSION: We report HOXD12 as a novel clubfoot disease gene and demonstrate a phenotypic expansion of known disease genes (myopathy gene COL12A1, Ehlers-Danlos syndrome gene COL9A3 and nail-patella syndrome gene LMX1B) to include isolated clubfoot.

Aponeurosis structure-function properties: Evidence of heterogeneity and implications for muscle function.

Aponeurosis is a sheath-like connective tissue that aids in force transmission from muscle to tendon and can be found throughout the musculoskeletal system. The key role of aponeurosis in muscle-tendon unit mechanics is clouded by a lack of understanding of aponeurosis structure-function properties. This work aimed to determine the heterogeneous material properties of porcine triceps brachii aponeurosis tissue with materials testing and evaluate heterogeneous aponeurosis microstructure with scanning electron microscopy. We found that aponeurosis may exhibit more microstructural collagen waviness in the insertion region (near the tendon) compared to the transition region (near the muscle midbelly) (1.20 versus 1.12, p = 0.055), which and a less stiff stress-strain response in the insertion versus transition regions (p < 0.05). We also showed that different assumptions of aponeurosis heterogeneity, specifically variations in elastic modulus with location can alter the stiffness (by more than 10x) and strain (by approximately 10% muscle fiber strain) of a finite element model of muscle and aponeurosis. Collectively, these results suggest that aponeurosis heterogeneity could be due to variations in tissue microstructure and that different approaches to modeling tissue heterogeneity alters the behavior of computational models of muscle-tendon units. STATEMENT OF SIGNIFICANCE: Aponeurosis is a connective tissue found in many muscle tendon units that aids in force transmission, yet little is known about the specific material properties of aponeurosis. This work aimed to determine how the properties of aponeurosis tissue varied with location. We found that aponeurosis exhibits more microstructural waviness near the tendon compared to near the muscle midbelly, which was associated with differences in tissue stiffness. We also showed that different variations in aponeurosis modulus (stiffness) can alter the stiffness and stretch of a computer model of muscle tissue. These results show that assuming uniform aponeurosis structure and modulus, which is common, may lead to inaccurate models of the musculoskeletal system.

Short-term vancomycin and buffer soaking does not change rabbit achilles tendon tensile material properties.

BACKGROUND: Allograft tendons are commonly used during orthopedic surgery to reconstruct tissue that is severely damaged. Soaking the tendon in an antibiotic solution, specifically vancomycin, has been shown to lower the risk of post-operative infections. While some material properties of tendon and ligament after antibiotic soaking have previously been characterized, extensive sub-failure allograft tendon material properties after soaking in antibiotic solutions have not. METHODS: Forty tendons were dissected from rabbits and soaked in either a phosphate buffered saline (PBS) only solution or vancomycin and PBS solution for five or 30 min. Immediately after soaking, quasi-static tensile experiments were performed in a materials testing system. FINDINGS: Tissue nominal stress, Lagrange strain, toe-region properties and elastic modulus were characterized. For all forty tendons, the average elastic modulus was found to be 455 ± 37 MPa, the average transition strain (from toe-region to linear elastic region) was 0.0487 ± 0.0035, and the average transition stress was 9.71 ± 0.79 MPa. No statistically significant differences in any of these material properties were found across soaking medium or soaking time. INTERPRETATION: From these results, we conclude that soaking an allograft tendon in antibiotic solution for up to 30 min prior to implantation does not change the tensile material properties of tendons, supporting current clinical practice.

Patellofemoral joint load and knee abduction/adduction moment are sensitive to variations in femoral version and individual muscle forces.

Torsional profiles of the lower limbs, such as femoral anteversion, can dictate gait and mobility, joint biomechanics and pain, and functional impairment. It currently remains unclear how the interactions between femoral anteversion, kinematics, and muscle activity patterns contribute to joint biomechanics and thus conditions such as knee pain. This study presents a computational modeling approach to investigating the interactions between femoral anteversion, muscle forces, and knee joint loads. We employed an optimal control approach to produce actuator and muscle-driven simulations of the stance phase of gait for femoral anteversion angles ranging from -8° (retroversion) to 52° (anteversion) with a typically developing baseline of 12° of anteversion and implemented a Monte Carlo analysis for variations in lower limb muscle forces. While total patellofemoral joint load decreased with increasing femoral anteversion, patellofemoral joint load alignment worsened, and knee abduction/adduction magnitude increased with both positive and negative changes in femoral anteversion (p < 0.001). The rectus femoris muscle was found to greatly influence patellofemoral joint loads across all femoral anteversion alignments (R > 0.8, p < 0.001), and the medial gastrocnemius was found to greatly influence knee abduction/adduction moments for the extreme version cases (R > 0.74, p < 0.001). Along with the vastus lateralis, which decreased with increasing femoral anteversion (R = 0.89, p < 0.001), these muscles are prime candidates for future experimental and clinical efforts to address joint pain in individuals with extreme femoral version. These findings, along with future modeling efforts, could help clinicians better design treatment strategies for knee joint pain in populations with extreme femoral anteversion or retroversion.

Risk of reoperation after primary anterior cruciate ligament reconstruction in children and adolescents.

OBJECTIVE: To examine the incidence and risk factors of any-cause reoperation after primary ACLR in children and adolescents. DESIGN: Retrospective Cohort. SETTING: Electronic medical records from a large tertiary care, single institution integrated healthcare delivery system. PATIENTS: Patients were under the age of 18 years and had anterior cruciate ligament reconstruction. They were excluded if they had a multi-ligamentous knee injury or <1 year follow-up. INTERVENTIONS: Patients were further identified to have undergone a subsequent knee operation ipsilaterally or contralateral ACLR. MAIN OUTCOME MEASURES: The rate of any-cause reoperation was our primary outcome measure. RESULTS: The median age was 16. There were 208 females (53.9%) and 178 males (46.1%) included. The median follow-up was 25 months with a minimum of 12 months (interquartile range: 16.0, 46.0). The rate of any-cause reoperation was 34.7%. There was no statistically significant difference between those who underwent reoperation versus those who did not undergo reoperation relative to age, sex, BMI, graft type, or the presence of concomitant meniscal injury. The rates of ipsilateral ACLR and contralateral ACLR at any time during the study period was 8.0% and 10.9% respectively. There was no statistically significant difference for rate of reoperation between graft types, between various concomitant injuries, between those who underwent meniscus repair or no repair. CONCLUSIONS: This study reflects a 34.7% rate of a subsequent knee operation after ACLR in patients younger than 18 years. These findings can be used to inform pediatric patients undergoing primary ACLR on their risk of returning to the operating room.

Orthopaedic Management of Loeys-Dietz Syndrome: A Systematic Review.

INTRODUCTION: Loeys-Dietz syndrome (LDS) is an autosomal dominant connective tissue disorder associated with aortic aneurysm/dissection in children. However, LDS may also present with a host of orthopaedic conditions. This study aimed to elucidate the management of orthopaedic conditions and associated outcomes in patients with LDS. METHODS: PubMed, Ovid MEDLINE, and Cochrane Library were systematically searched for primary articles regarding the management of orthopaedic conditions in patients with LDS. The goals and findings of each included study were described. Data regarding demographics, conditions studied, treatment modalities, and outcomes were extracted and analyzed. RESULTS: Three hundred sixty-two unique articles were retrieved, 13 of which were included, with 4 retrospective cohort studies and 9 case reports representing 435 patients. In total, 19.8% of patients presenting with orthopaedic conditions received surgical treatment;54.3% of them experienced adverse outcomes, and 44.4% required revision surgery. The mean age at surgery was 9.0 ± 2.1 years. CONCLUSION: Patients with LDS may require early surgical intervention for a variety of orthopaedic conditions and may be at an increased risk for surgical complications. The current LDS literature is primarily focused on spinal conditions with a relative paucity of data on the management of hip deformity, joint subluxation, clubfoot, and trauma. Additional research is required regarding orthopaedic management for this unique population.

Teaching the Basics: Development and Validation of a Distal Radius Reduction and Casting Model.

BACKGROUND: Approximately one-third of reduced pediatric distal radius fractures redisplace, resulting in further treatment. Two major modifiable risk factors for loss of reduction are reduction adequacy and cast quality. Closed reduction and immobilization of distal radius fractures is an Accreditation Council for Graduate Medical Education residency milestone. Teaching and assessing competency could be improved with a life-like simulation training tool. QUESTIONS/PURPOSES: Our goal was to develop and validate a realistic distal radius fracture reduction and casting simulator as determined by (1) a questionnaire regarding the "realism" of the model and (2) the quantitative assessments of reduction time, residual angulation, and displacement. METHODS: A distal radius fracture model was created with radiopaque bony segments and articulating elbows and shoulders. Simulated periosteum and internal deforming forces required proper reduction and casting techniques to achieve and maintain reduction. The forces required were estimated through an iterative process through feedback from experienced clinicians. Embedded monofilaments allowed for quantitative assessment of residual displacement and angulation through the use of fluoroscopy. Subjects were asked to perform closed reduction and apply a long arm fiberglass cast. Primary performance variables assessed included reduction time, residual angulation, and displacement. Secondary performance variables consisted of number of fluoroscopic images, casting time, and cast index (defined as the ratio of the internal width of the forearm cast in the sagittal plane to the internal width in the coronal plane at the fracture site). Subject grading was performed by two blinded reviewers. Interrater reliability was nearly perfect across all measurements (intraclass correlation coefficient range, 0.94-0.99), thus disagreements in measurements were handled by averaging the assessed values. After completion the participants answered a Likert-based questionnaire regarding the realism of simulation. Eighteen participants consented to participate in the study (eight attending pediatric orthopaedic surgeons, six junior residents, four senior residents). The performances of junior residents (Postgraduate Year [PGY] 1-2), senior residents (PGY 3-5), and attending surgeons were compared using one-way ANOVA with Tukey's-adjusted pairwise comparisons. RESULTS: The majority of participants (15 of 18) felt that the model looked, felt, and moved like a human forearm. All participants strongly agreed that the model taught the basic steps of fracture reduction and should be implemented in orthopaedic training. Attending surgeons reduced fractures in less time than junior residents (60 ± 27 seconds versus 460 ± 62 seconds; mean difference, 400 seconds; 95% CI, 335-465 seconds; p < 0.001). Residual angulation was greater for junior residents when compared with attending surgeons on AP (7° ± 5° versus 0.7° ± 0.9°; mean difference, 6.3°; 95% CI, 3°-11°; p = 0.003) and lateral (27° ± 7° versus 7° ± 5°; mean difference, 20°; 95% CI, 13°-27°; p = 0.001) radiographs. Similarly, residual displacement was greater for junior residents than either senior residents (mean difference, 16 mm; 95% CI, 2-34 mm; p = 0.05) or attending surgeons (mean difference, 15 mm; 95% CI, 3-27 mm; p = 0.02) on lateral images. There were no differences identified in secondary performance variables (number of fluoroscopic images, casting time, and cast index) between groups. CONCLUSIONS: This is the first distal radius fracture reduction model to incorporate an elbow and shoulder and allow quantitative assessment of the fracture reduction. This simulator may be useful in an orthopaedic resident training program to help them reach a defined minimum level of competency. This simulator also could easily be integrated in other accreditation and training programs, including emergency medicine. LEVEL OF EVIDENCE: Level II, therapeutic study.

Utility of Postoperative Antibiotics After Percutaneous Pinning of Pediatric Supracondylar Humerus Fractures.

BACKGROUND: Pediatric supracondylar humerus fractures are common injuries that are often treated surgically with closed reduction and percutaneous pinning. Although surgical-site infections are rare, postoperative antibiotics are frequently administered without evidence or guidelines for their use. With the increasing prevalence of antibiotic-resistant organisms and heightened focus on health care costs, appropriate and evidence-based use of antibiotics is needed. We hypothesized that postoperative antibiotic administration would not decrease the rate of surgical-site infection. METHODS: A billing query identified 951 patients with operatively treated supracondylar humerus fractures at our institution over a 15-year period. Records were reviewed for demographic data, perioperative antibiotic use, and the presence of surgical-site infection. Exclusion criteria were open fractures, open reduction, pathologic fractures, metabolic bone disease, the presence of other injuries that required operative treatment, and follow-up <2 weeks after pin removal. χ and Fisher exact test were used to compare antibiotic use to the incidence of surgical-site infection. RESULTS: Six hundred eighteen patients met our inclusion criteria. Two hundred thirty-eight patients (38.5%) received postoperative antibiotics. Eleven surgical-site infections were identified for an overall rate of 1.8%. The use of postoperative antibiotics was not associated with a lower rate of surgical-site infection (P=0.883). Patients with a type III fracture (P<0.001), diminished preoperative vascular (P=0.001) and neurological status (P=0.019), and postoperative hospital admission (P<0.001) were significantly more likely to receive postoperative antibiotics. CONCLUSIONS: Administration of postoperative antibiotics after closed reduction and percutaneous pinning of pediatric supracondylar humerus fractures does not decrease the rate of surgical-site infection. LEVEL OF EVIDENCE: Level III-therapeutic.

Pediatric Lyme Arthritis of the Hip: The Great Imitator?

BACKGROUND: Lyme arthritis (LA) of the hip can present similarly to septic arthritis (SA) and transient synovitis (TS). The primary purpose of this study was to determine clinical and laboratory parameters differentiating LA of the hip from SA or TS among children who had undergone hip aspiration during the evaluation of hip pain. METHODS: This was a retrospective review of all patients who underwent hip aspiration for the evaluation of hip pain at a tertiary care children's hospital in a Lyme endemic area. Clinical and laboratory data were reviewed and comparative analyses were performed between those diagnosed with LA, SA, and TS. Independent samples t test, ANOVA, and χ test were used to compare clinical and laboratory variables as appropriate. Multivariable logistic regression was used to elucidate independent predictors of LA. Statistical significance was set at P<0.05. RESULTS: Ninety-three hip aspirations (93 patients) were included in the final analysis. Seventeen patients were diagnosed with LA, 40 with SA, and 36 with TS. Multivariable logistic regression revealed febrile history (OR=16.3; 95% CI, 2.35-113.0) and increased peripheral white blood cell (WBC) count (OR=1.26; 95% CI, 1.01-1.58) to be significantly associated with increased odds of being diagnosed with SA versus LA. Increased erythrocyte sedimentation rate (ESR) was significantly associated with increased odds of being diagnosed with LA versus TS (OR=1.06; 95% CI, 1.02-1.10), whereas febrile history (OR=0.06; 95% CI, 0.01-0.49) and increased peripheral WBC count (OR=0.8; 95% CI, 0.65-0.98) were associated with decreased odds of LA. CONCLUSIONS: Children presenting in a Lyme endemic area with an isolated hip effusion are more likely to have LA versus SA if they have no history of fever and a decreased peripheral WBC count. Compared with TS, patients with LA are more likely to have an elevated ESR. This study adds to existing knowledge because there are few investigations examining isolated LA of the hip. LEVEL OF EVIDENCE: Level III-retrospective case-control study.

Cost Savings From Utilization of an Ambulatory Surgery Center for Orthopaedic Day Surgery.

INTRODUCTION: Healthcare providers are increasingly searching for ways to provide cost-efficient, high-quality care. Previous studies on evaluating cost used estimated cost-to-charge ratios, which are inherently inaccurate. The purpose of this study was to quantify actual direct cost savings from performing pediatric orthopaedic sports day surgery at an ambulatory surgery center (ASC) compared with a university-based children's hospital (UH). METHODS: Custom-scripted accounting software was queried for line-item costs for a period of 3 fiscal years (fiscal year 2012 to fiscal year 2014) for eight day surgery procedures at both a UH and a hospital-owned ASC. Hospital-experienced direct costs were compared while controlling for surgeon, concomitant procedures, age, sex, and body mass index. RESULTS: One thousand twenty-one procedures were analyzed. Using multiple linear regression analysis, direct cost savings at the ASC ranged from 17% to 43% for seven of eight procedures. Eighty percent of the cost savings was attributed to time (mean, 64 minutes/case; P < 0.001) and 20% was attributed to supply utilization (P < 0.001). Of the time savings in the operating room, 73% (mean, 47 minutes; P < 0.001) was attributed to the surgical factors whereas 27% (17 minutes; P < 0.001) was attributed to anesthesia factors. CONCLUSIONS: Performing day surgery at an ASC, compared with a UH, saves 17% to 43% from the hospital's perspective, which was largely driven by surgical and anesthesia-related time expenditures in the operating room. LEVEL OF EVIDENCE: Level II.

Femoral Deformity May Be More Predictive of Hip Range of Motion Than Severity of Acetabular Disease in Patients With Acetabular Dysplasia: An Analysis of the ANCHOR Cohort.

BACKGROUND: It is generally believed that acetabular dysplasia (AD) is associated with increased hip range of motion (ROM). The purpose of this study was to investigate the associations between dysplasia severity and hip ROM in a large multicenter cohort. METHODS: A prospective registry of patients undergoing periacetabular osteotomy for symptomatic AD by 1 of 13 surgeons was used to analyze 1,051 patients (mean age, 26 ± 10 years). Multivariable linear regression modeling was used to investigate for associations between dysplasia severity (severe, <5°; moderate, 5° to 15°; mild, >15°), α angle, and hip ROM. RESULTS: When controlling for age, sex, body mass index, and α angle, only internal (α = 1.94; P = 0.005) and external (α = -2.63; P < 0.001) rotation in extension were significantly different between groups with increasing dysplasia severity. Alpha angle was greater for those with severe AD compared with subjects with mild disease (60° ± 16° versus 57° ± 15°; P = 0.038). Alpha angle was also significantly correlated with rotational ROM parameters (internal and external rotation in flexion and extension) (Pearson r, range: -0.077 to -0.216; P < 0.05 for all), but not with linear motion. CONCLUSIONS: Internal rotation in extension was directly associated with dysplasia severity, whereas external rotation in extension was inversely associated. Furthermore, α angle was greater with increasing dysplasia severity and predictive of rotational ROM parameters. Taken together, these data suggest that femoral-sided deformity, including α angle and possibly femoral version, may be responsible for differences in ROM based on dysplasia severity. LEVEL OF EVIDENCE: Level III, Prognostic.

Change in Size of Hamstring Grafts During Preparation for ACL Reconstruction: Effect of Tension and Circumferential Compression on Graft Diameter.

BACKGROUND: There is good consensus that anterior cruciate ligament (ACL) grafts should be pretensioned to remove creep prior to implantation, but the literature contains little information on the influence of graft preparation or circumferential compression on graft size. The purpose of this study was to investigate how the size of hamstring allografts changes as they are prepared for ACL reconstruction. We hypothesized that grafts decrease in diameter as they are prepared with both tension and circumferential compression. We also investigated the interrater reliability of graft diameter measurements during each step of graft preparation. METHODS: Twenty pairs of fresh-frozen human hamstring tendons obtained from an allograft supplier were prepared in a standardized fashion for ACL reconstruction (suturing followed by longitudinal tensioning followed by circumferential compression followed by relaxation). Four blinded raters measured each graft in a sequential manner after each graft preparation step. Interrater reliability was assessed using the intraclass correlation coefficient ICC(2,1). The mean allograft diameter at each time point was calculated and compared across all time points using repeated-measures analysis of variance (ANOVA). RESULTS: Subjecting the grafts to both tension and circumferential compression significantly decreased their mean diameter (to 7.38 mm compared with 8.28 mm at baseline; p = 0.044). Interrater reliability revealed almost perfect agreement at each measurement interval, with the ICC ranging from 0.933 to 0.961. CONCLUSIONS: The average diameter of hamstring ACL grafts decreases by almost 1 mm after they are subjected to both tension and circumferential compression within a standard cylindrical sizing block. CLINICAL RELEVANCE: Because ACL bone tunnels are drilled in 0.5-mm increments, preparing soft-tissue grafts with circumferential compression in addition to tension may allow creation of tunnels that are one to two incremental sizes smaller. This could permit less bone removal, which may be particularly applicable for certain reconstruction techniques such as pediatric, double-bundle, or revision ACL reconstruction, in which limited space is available for tunnel drilling.

Prevalence of acetabular labral tears in asymptomatic children.

PURPOSE: Magnetic resonance imaging (MRI) is a sensitive, non-invasive modality to diagnose acetabular labral pathology, and the normal variants of the acetabular labrum have been characterized in adults. However, the prevalence of labral pathology in the asymptomatic pediatric population is unknown. METHODS: All pelvic MRIs performed at a large tertiary-care children's hospital were reviewed during one calendar year (2014). Only patients aged between 2 and 18 years were included, and scans were excluded for hip pain/pathology or technical inadequacy. A blinded pediatric musculoskeletal radiologist read all eligible scans for the presence or absence of a labral tear. RESULTS: Three hundred and ninety-four pelvic MRIs were screened, and patients were excluded for hip pain/pathology (85 subjects), or technical inadequacy (190 subjects). One hundred and eight subjects (216 hips) met the inclusion criteria and were technically adequate for analysis. Labral tears were visualized in three of 216 (1.4 %) hips (two of the 110 subjects; 1.9 %). CONCLUSIONS: There is a low rate of asymptomatic labral pathology by MRI in pediatric patients. The clinical history remains the means of differentiating real labral pathology from spurious imaging findings. LEVEL OF EVIDENCE IV: Case series (prevalence).

Core Concepts: Orthopedic Intern Curriculum Boot Camp.

Orthopedic surgical interns must gain a broad array of clinical skills in a short time. However, recent changes in health care have limited resident-patient exposures. With the reported success of simulation training in the surgical literature, the American Board of Orthopaedic Surgery (ABOS) and Residency Review Committee for Orthopaedic Surgery have required that surgical simulation training be a component of the intern curricula in orthopedic surgical residencies. This study examined the short-term effectiveness of an orthopedic "intern boot camp" covering 7 of 17 simulation training concept modules published by the ABOS. Eight orthopedic post-graduate year 1 (PGY-1) residents (study group) completed a structured 3-month curriculum and were compared with 7 post-graduate year 2 (PGY-2) residents (comparison group) who had just completed their orthopedic surgical internship. Seven core skills were assessed using both task-specific and global rating scales. The PGY-1 residents demonstrated a statistically significant improvement in all 7 modules with respect to their task-specific pre-test scores: sterile technique (P=.001), wound closure (P<.001), knot tying (P=.017), casting and splinting (P<.001), arthrocentesis (P=.01), basics of internal fixation (P<.001), and compartment syndrome evaluation (P=.004). After the camp, PGY-1 and -2 scores in task-specific measures were not significantly different. A 3-month simulation-based boot camp instituted early in orthopedic internship elevated a variety of clinical skills to levels exhibited by PGY-2 residents.

Computer-Simulated Arthroscopic Knee Surgery: Effects of Distraction on Resident Performance.

Orthopedic surgeons cite "full focus" and "distraction control" as important factors for achieving excellent outcomes. Surgical simulation is a safe and cost-effective way for residents to practice surgical skills, and it is a suitable tool to study the effects of distraction on resident surgical performance. This study investigated the effects of distraction on arthroscopic knee simulator performance among residents at various levels of experience. The authors hypothesized that environmental distractions would negatively affect performance. Twenty-five orthopedic surgery residents performed a diagnostic knee arthroscopy computer simulation according to a checklist of structures to identify and tasks to complete. Participants were evaluated on arthroscopy time, number of chondral injuries, instances of looking down at their hands, and completion of checklist items. Residents repeated this task at least 2 weeks later while simultaneously answering distracting questions. During distracted simulation, the residents had significantly fewer completed checklist items (P<.02) compared with the initial simulation. Senior residents completed the initial simulation in less time (P<.001), with fewer chondral injuries (P<.005) and fewer instances of looking down at their hands (P<.012), compared with junior residents. Senior residents also completed 97% of the diagnostic checklist, whereas junior residents completed 89% (P<.019). During distracted simulation, senior residents continued to complete tasks more quickly (P<.006) and with fewer instances of looking down at their hands (P<.042). Residents at all levels appear to be susceptible to the detrimental effects of distraction when performing arthroscopic simulation. Addressing even straightforward questions intraoperatively may affect surgeon performance.

Does Perfusion MRI After Closed Reduction of Developmental Dysplasia of the Hip Reduce the Incidence of Avascular Necrosis?

BACKGROUND: Gadolinium-enhanced perfusion MRI (pMRI) after closed reduction/spica casting for developmental dysplasia of the hip (DDH) has been suggested as a potential means to identify and avoid avascular necrosis (AVN). To date, however, no study has evaluated the effectiveness of pMRI in clinical practice or compared it with other approaches (such as postreduction CT scan) to show a difference in the proportion of AVN. QUESTIONS/PURPOSES: (1) Can a pMRI-based protocol be used immediately post closed reduction to minimize the risk that AVN would develop? (2) What are the overall hip-related outcomes after closed reduction/spica casting using this protocol? (3) Do any patient-specific factors at the time of closed reduction predict future AVN? METHODS: This was a retrospective cohort study at a large tertiary care children's hospital. Between 2009 and 2013 we treated 43 patients with closed reduction/spica casting for DDH, of whom 33 (77%) received a postreduction pMRI. All patients were indicated for pMRI per treating surgeon preference. A convenience sample totaling 25 hips in 22 patients treated with pMRI was then established using the following exclusion criteria: DDH of neuromuscular/syndromic origin, failed initial closed reduction, less than 1 year of clinical and radiographic followup, and subsequent open reduction. Next, the 40 patients treated with closed reduction between 2004 and 2009 were screened until the chronologically most recent 25 hips (after applying the previously mentioned exclusion criteria) were identified in 21 of the first 34 patients (62%) screened. Although termed the CT group, specific postreduction imaging was not a defined inclusion criterion in this group with the majority (21 of 25 [84%]) receiving postreduction CT and the remainder (four of 25 [16%]) receiving only postreduction radiographs. All hips with globally decreased femoral head perfusion on postreduction pMRI were treated with immediate cast removal followed by repeat closed reduction or open reduction, as per surgeon preference, with two of 33 (6%) requiring such further interventions. Salter criteria were then used to determine the proportion of AVN on radiographs at 1-year and final followup. Secondary outcomes including residual dysplasia and the need for further corrective surgery were ascertained through radiographic and retrospective chart review. RESULTS: At 1-year followup there was no difference in the proportion of AVN in the historical CT group as compared with the pMRI group (six of 25 [24%] versus one of 25 [4%]; odds ratio [OR], 7.6; 95% confidence interval [CI], 0.8-363; p = 0.098). However, by final followup there was a statistically higher proportion of AVN in the CT group (seven of 25 [28%] versus one of 25 [4%]; OR, 9.3; 95% CI, 1.0-438; p = 0.049). No patient with normal perfusion on postreduction pMRI went on to develop AVN. In those pMRI patients in whom a successful reduction was initially obtained, two of 25 (8%) went on to require further corrective surgery and one of 25 (4%) had a redislocation event. With the numbers available, no patient-specific factors at the time of closed reduction were predictive of future AVN, including the patient's age/weight, the presence of an ossific nucleus, history of previous bracing treatment, or the abduction angle in spica cast. CONCLUSIONS: A pMRI-based protocol immediately after closed reduction/spica casting may decrease the risk of AVN by helping the surgeon to evaluate femoral head vascularity. Although preliminary in nature, this study could serve to guide further investigation into the potential role of pMRI for the treatment of patients who require closed reduction/spica casting for DDH. LEVEL OF EVIDENCE: Level III, therapeutic study.

Medial Epicondyle Fractures in Children and Adolescents: Shifting Care from General Hospitals to Children's Hospitals?

OBJECTIVES: To determine if there is a shift in the treatment of children with medial epicondyle fractures toward children's hospitals, and to explore potential confounders of any observed effect. STUDY DESIGN: The Healthcare Cost and Utilization Project Kids' Inpatient Database was used to examine the epidemiology of medial epicondyle fractures, particularly with attention to whether they were admitted to a general hospital or a children's hospital (defined as free-standing children's hospitals, specialty children's hospitals, and children's units within general hospitals). Age and insurance payer status were also collected and evaluated as potential confounders. RESULTS: The proportion of medial epicondyle hospital discharges from children's hospitals increased (from 29%-46%; P < .001), and the proportion of discharges from general hospitals declined over the study period (from 71%-42%; P < .001). Age and insurance payer status both remained consistent throughout the study period and did not contribute to this finding. CONCLUSIONS: This study demonstrates an increase in the proportion of discharges for pediatric medial epicondyle fractures from children's hospitals. Although this finding is likely multifactorial, it may represent increasing subspecialization and increasing medical liability when treating children. Children's hospitals should identify those conditions which will continue to increase in number and consider constructing clinical pathways in order to optimize delivery of care and resource utilization.

The presentation of Legg-Calvé-Perthes disease in females.

PURPOSE: Legg-Calvé-Perthes disease (LCPD) is uncommon in girls. The presentation of LCPD in female patients has been reported as later in onset and associated with certain high-impact activities. Our aim is to characterize the presentation of female LCPD at a large center, with particular attention to the clinical and radiographic features of late-onset disease (>ten years of age). We perceived an increasing burden of late-onset disease with adult-like radiographic features. METHODS: All patients presenting to a single large urban children's hospital from 1990-2014 with a diagnosis of LCPD were reviewed. Demographic, clinical, and radiographic data for all female patients were examined and compared to historical norms. RESULTS: Four-hundred and fifty-one patients presented with LCPD in the study period, of which 82 (18.2 %) were female. The average age at presentation was 6.58 years in girls, which is similar to the classically reported mean age. Fourteen patients participated in high-impact repetitive activities or those with deep flexion and abduction, although few were late presenters. There were four female patients who presented for initial diagnosis >ten years of age. CONCLUSIONS: There was a paucity of late-onset LCPD in girls in the study population, and the females with LCPD had a very similar age and character to their presentation as did males. Although their presentation is infrequent, three of four older females with LCPD were engaged in high-level physical activity, and their disease may be attributed to high-impact, repetitive athletics. LEVEL OF EVIDENCE: Case series, Level IV.

Positional Occlusion of an Interposition Vein Graft for Brachial Artery Reconstruction Following Open Elbow Dislocation in a Pediatric Patient: A Case Report.

CASE: We present a case of positional occlusion of the brachial artery after open elbow dislocation and vein graft reconstruction in a pediatric patient. Two years after reconstruction, arterial Doppler studies demonstrated occlusion of the artery; however, an angiogram revealed a widely patent artery. Given the clinical findings of pain and cold intolerance, the patient underwent surgical exploration. Arterial occlusion was found to coincide with elbow flexion. The redundant segment of the basilic vein graft was resected and repaired end-to-end. CONCLUSIONS: Vein graft reconstruction of the brachial artery should be checked for patency in flexion prior to closing the incision. Vein grafts with lengths in excess of a defect may kink in flexion due to redundant graft and the relatively thin walls of veins compared to arteries. This case report emphasizes that an understanding of routine tests is invaluable when eliciting the etiology of contradictory test results.