- Orthopaedic Surgery
- Pediatric Orthopaedic Surgery
Clinical Assistant Professor, Orthopaedic Surgery
Clinical Assistant Professor of Orthopedic Surgery, Stanford University (2015 - Present)
Medical Education:University of Southern California Keck School of Medicine Registrar (2009) CA
Board Certification: Orthopaedic Surgery, American Board of Orthopaedic Surgery (2017)
Residency:Stanford University Orthopaedic Surgery Residency (2014) CA
Internship:UCSD Orthopaedic Surgery (2010) CA
Fellowship:Stanford University Pediatric Orthopaedics Fellowship (2015) CA
Fellowship, Stanford University, Pediatric Orthopaedic Surgery (2015)
Transepiphyseal (Type VII) Ankle Fracture Versus Os Subfibulare in Pediatric Ankle Injuries.
Journal of pediatric orthopedics
BACKGROUND: Pediatric ankle injuries are common, giving rise to 17% of all physeal injuries. An os subfibulare in a child with an ankle sprain may be confused with a type VII transepiphyseal fracture. Here, we evaluate the clinical and radiographic features of type VII transepiphyseal fractures to those of os subfibulare presenting with acute ankle trauma with the hypothesis that radiographs are necessary for final diagnosis and neither clinical history nor examination would be diagnostic.METHODS: We performed an internal review board-approved, retrospective chart review of patients identified with a traumatic os subfibulare or type VII ankle fracture over an 18-month period. Charts were reviewed for demographics, mechanism, and clinical findings on initial presentation. Radiographic measurements of the distal fibular fragment as well as epiphysis were made on presenting ankle series radiographs.RESULTS: A total of 23 patients were identified. Eleven patients had a traumatic type VII ankle fracture and 12 had trauma associated with an os subfibulare on initial radiographs. The history and clinical presentations were similar and were nondiagnostic. The ratio of the width of the fibula at its largest point on the anterior posterior view to the width of the fibular fragment was significantly larger in the type VII ankle fractures (P=0.05). All os subfibulare were located within the inferior third of the epiphysis, whereas all type VII fractures were either at the equator or within the middle third of the fibular epiphysis.CONCLUSIONS: Radiographs, not clinical presentation, can differentiate an os subfibulare from a type VII transepiphyseal fracture. Children with type VII fractures have a long, irregular fracture line within the middle third of the distal fibular epiphysis. Those with an ankle sprain and os subfibulare have a smooth-edged ossicle of relatively short length located within the inferior pole of the epiphysis. Furthermore, the radiographic width of the fragment in the type VII fractures is significantly larger in width than the os subfibulare.LEVEL OF EVIDENCE: Level II.
View details for PubMedID 30199459
Proximal Tibial Fractures in the Pediatric Population.
The journal of knee surgery
Injuries about the proximal tibia are quite common in children. Understanding the mechanisms of injury and treatment strategies is imperative for practitioners caring for these patients. Similarly, appreciating the anatomy of the proximal tibia and the adjacent neurovascular structures can assist a practitioner in recognizing the potential associated risks following fracture. Patients with injuries about the proximal tibia require long-term follow-up, and knowledge of the natural history of these fractures is imperative.
View details for DOI 10.1055/s-0038-1636911
View details for PubMedID 29514377
Pediatric Supracondylar Humerus Fractures: Does After-Hours Treatment Influence Outcomes?
Journal of orthopaedic trauma
2018; 32 (6): e215–e220
To compare the outcomes of pediatric supracondylar humerus fractures treated during daytime hours to those treated after-hours.Retrospective.Academic Level I trauma center.Two hundred ninety-eight pediatric patients treated with surgical reduction and fixation of closed supracondylar fractures were included.Seventy-seven patients underwent surgery during daytime hours (06:00-15:59 on weekdays). One hundred eighty-six patients underwent surgery after-hours (16:00-05:59 on weekdays and any surgery on weekends or holidays).Surgeon subspecialty, operative duration, and radiographic and clinical outcomes, including range of motion and carrying angle, were extracted from the patient medical records.There were no patient-related demographic differences between the daytime hours and after-hours groups. Daytime surgery was more likely to be performed by a pediatric orthopaedic surgeon than after-hours surgery. Fractures treated after-hours had more severe injury patterns. After-hours surgery was not independently associated with rate of open reduction, operative times, complications, achievement of functional range of motion, or radiographic alignment. A late-night surgery subgroup analysis demonstrated an increased rate of malunion in patients undergoing surgery between the hours of 23:00 and 05:59.There is no difference in the operative duration or outcomes after surgical treatment of pediatric supracondylar humerus fractures performed after-hours when compared with daytime surgery. However, late-night surgery performed between 23:00 and 05:59 may be associated with a higher rate of malunion. Surgeons can use these data to make better-informed decisions about the timing of surgery in this patient population.Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
View details for PubMedID 29432316
Local versus distal transplantation of human neural stem cells following chronic spinal cord injury
2016; 16 (6): 764-769
Previous studies have demonstrated functional recovery of rats with spinal cord contusions after transplantation of neural stem cells adjacent to the site of acute injury.The purpose of the study was to determine if the local or distal injection of neural stem cells can cause functional difference in recovery after chronic spinal cord injury.Twenty-four adult female Long-Evans hooded rats were randomized into four groups, with six animals in each group: two experimental and two control groups. Functional assessment was measured after injury and then weekly for 6 weeks using the Basso, Beattie, and Bresnahan locomotor rating score. Data were analyzed using two-sample t test and linear mixed-effects model analysis.Posterior exposure and laminectomy at the T10 level was used. Moderate spinal cord contusion was induced by the Multicenter Animal Spinal Cord Injury Study Impactor with 10-g weight dropped from a height of 25 mm. Experimental subjects received either a subdural injection of human neural stem cells (hNSCs) locally at the injury site or intrathecal injection of hNSCs through a separate distal laminotomy 4 weeks after injury. Controls received control media injection either locally or distally.A statistically significant functional improvement in subjects that received hNSCs injected distally to the site of injury was observed when compared with the control (p=.042). The difference between subjects that received hNSCs locally and the control did not reach statistical significance (p=.085).The transplantation of hNSCs into the contused spinal cord of a rat led to significant functional recovery of the spinal cord when injected distally but not locally to the site of chronic spinal cord injury.
View details for DOI 10.1016/j.spinee.2015.12.007
View details for Web of Science ID 000378201100035
View details for PubMedID 26698654
The Inadequacy of Pediatric Fracture Care Information in Emergency Medicine and Pediatric Literature and Online Resources.
Journal of pediatric orthopedics
2015; 35 (7): 769-773
Emergency medicine and pediatric physicians often provide initial pediatric fracture care. Therefore, basic knowledge of the various treatment options is essential. The purpose of this study was to determine the accuracy of information commonly available to these physicians in textbooks and online regarding the management of pediatric supracondylar humerus and femoral shaft fractures.The American Academy of Orthopaedic Surgeons Clinical Practice Guidelines for pediatric supracondylar humerus and femoral shaft fractures were used to assess the content of top selling emergency medicine and pediatric textbooks as well as the top returned Web sites after a Google search. Only guidelines that addressed initial patient management were included. Information provided in the texts was graded as consistent, inconsistent, or omitted.Five emergency medicine textbooks, 4 pediatric textbooks, and 5 Web sites were assessed. Overall, these resources contained a mean 31.6% (SD=32.5) complete and correct information, whereas 3.6 % of the information was incorrect or inconsistent, and 64.8% was omitted. Emergency medicine textbooks had a mean of 34.3% (SD=28.3) correct and complete recommendations, 5.7% incorrect or incomplete recommendations, and 60% omissions. Pediatric textbooks were poor in addressing any of the American Academy of Orthopaedic Surgeons guidelines with an overall mean of 7.14% (SD=18.9) complete and correct recommendations, a single incorrect/incomplete recommendation, and 91.1% omissions. Online resources had a mean of 48.6% (SD=33.1) complete and correct recommendations, 5.72% incomplete or incorrect recommendations, and 45.7% omissions.This study highlights important deficiencies in resources available to pediatric and emergency medicine physicians seeking information on pediatric fracture management. Information in emergency medicine and pediatric textbooks as well as online is variable, with both inaccuracies and omissions being common. This lack of high-quality information could compromise patient care. Resources should be committed to ensuring accurate and complete information is readily available to all physicians providing pediatric fracture care. In addition, orthopaedic surgeons should take an active role to ensure that nonorthopaedic textbooks and online resources contain complete and accurate information.Level IV.
View details for DOI 10.1097/BPO.0000000000000357
View details for PubMedID 25393570
Proximal femur shape differs between subjects with lateral and medial knee osteoarthritis and controls: the Osteoarthritis Initiative
OSTEOARTHRITIS AND CARTILAGE
2014; 22 (12): 2067-2073
This study examined the association of proximal femur shape with ipsilateral medial and lateral compartment knee osteoarthritis (OA).Radiographs were obtained from the NIH-funded Osteoarthritis Initiative (OAI). Cases of isolated radiographic lateral compartment knee OA were defined on baseline radiographs as Kellgren/Lawrence (K/L) Grade ≥ 2 and joint space narrowing (JSN) > 0 in the lateral compartment and JSN = 0 in the medial compartment; isolated medial compartment knee OA had K/L ≥ 2 and JSN > 0 medially with JSN = 0 in the lateral compartment. Controls had K/L < 2 and JSN = 0 in both compartments. Controls were frequency matched to cases by sex and 10-year age intervals. We characterized the shape of the proximal femurs on radiographs using Active Shape Modeling (ASM) and determined the association of proximal femur shape with knee OA using logistic regression.There were 168 lateral compartment knee OA cases (mean body mass index (BMI) 29.72 ± 5.26), 169 medial compartment knee OA cases (mean BMI 29.68 ± 4.83) and 168 controls (mean BMI 26.87 ± 4.2). Thirteen modes were derived for femur shape which described 95.5% of the total variance in proximal femur shape in the population. Modes 6, 8 and 12 were associated with prevalent lateral compartment knee OA. Medial compartment knee OA was associated with proximal femur modes 1, 5, 8, and 12.Prevalent lateral and medial compartment knee OA are associated with different ipsilateral proximal femur shapes. Additional studies are needed to better define how the shape of the proximal femur influences compartment-specific knee OA.
View details for DOI 10.1016/j.joca.2014.08.013
View details for Web of Science ID 000345149100012
View details for PubMedID 25194496
Functional task kinematics of the thumb carpometacarpal joint.
Clinical orthopaedics and related research
2014; 472 (4): 1123-1129
Abnormal biomechanical loading has been identified as an associated risk factor of osteoarthritis in the wrist and hand. Empirical data to date are insufficient to describe the role of altered biomechanics in thumb carpometacarpal (CMC) arthritis.This is a pilot study to evaluate motion analysis of the upper extremity while performing functional tasks. We wished to describe the in vivo kinematics of the thumb and hand in relation to the larger joints of the upper extremity in subjects without arthritis in functional positions at rest and while loading the CMC joint. If reproducible, we then planned to compare kinematics between these subjects and a subject with advanced thumb CMC arthritis.In vivo kinematics of the hand and upper extremity during the functional tasks of grasp, jar opening, and pinch with and without loading of the CMC joint were evaluated using cameras and a motion-capture system in four asymptomatic female subjects and one female subject with advanced radiographic (Eaton Stage IV) osteoarthritis.Kinematics of the hand and upper extremity can be reliably quantified. Loading of the CMC joint did not alter the hand and forearm kinematics in control subjects. In the subject with osteoarthritis, the adduction-extension deformity at the CMC joint resulted in kinematic alterations as compared with the four control subjects.This study represents preliminary steps in defining thumb CMC position, motion, and loading associated with activities of daily living. These findings enhance our understanding of motion at the CMC joint and how it differs in arthritic patients.Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.
View details for DOI 10.1007/s11999-013-2964-0
View details for PubMedID 23549712
View details for PubMedCentralID PMC3940744
Active Shape Modeling of the Hip in the Prediction of Incident Hip Fracture
JOURNAL OF BONE AND MINERAL RESEARCH
2011; 26 (3): 468-474
The objective of this study was to evaluate right proximal femur shape as a risk factor for incident hip fracture using active shape modeling (ASM). A nested case-control study of white women 65 years of age and older enrolled in the Study of Osteoporotic Fractures (SOF) was performed. Subjects (n = 168) were randomly selected from study participants who experienced hip fracture during the follow-up period (mean 8.3 years). Controls (n = 231) had no fracture during follow-up. Subjects with baseline radiographic hip osteoarthritis were excluded. ASM of digitized right hip radiographs generated 10 independent modes of variation in proximal femur shape that together accounted for 95% of the variance in proximal femur shape. The association of ASM modes with incident hip fracture was analyzed by logistic regression. Together, the 10 ASM modes demonstrated good discrimination of incident hip fracture. In models controlling for age and body mass index (BMI), the area under receiver operating characteristic (AUROC) curve for hip shape was 0.813, 95% confidence interval (CI) 0.771-0.854 compared with models containing femoral neck bone mineral density (AUROC = 0.675, 95% CI 0.620-0.730), intertrochanteric bone mineral density (AUROC = 0.645, 95% CI 0.589-0.701), femoral neck length (AUROC = 0.631, 95% CI 0.573-0.690), or femoral neck width (AUROC = 0.633, 95% CI 0.574-0.691). The accuracy of fracture discrimination was improved by combining ASM modes with femoral neck bone mineral density (AUROC = 0.835, 95% CI 0.795-0.875) or with intertrochanteric bone mineral density (AUROC = 0.834, 95% CI 0.794-0.875). Hips with positive standard deviations of ASM mode 4 had the highest risk of incident hip fracture (odds ratio = 2.48, 95% CI 1.68-3.31, p < .001). We conclude that variations in the relative size of the femoral head and neck are important determinants of incident hip fracture. The addition of hip shape to fracture-prediction tools may improve the risk assessment for osteoporotic hip fractures.
View details for DOI 10.1002/jbmr.254
View details for Web of Science ID 000287827600006
View details for PubMedID 20878772