- Neuromuscular disorders
- Complex limb deformity
- Skeletal Dysplasia
- Pediatric hip reconstruction
- Leg length inequality
- Orthopaedic Surgery
Clinical Professor, Orthopaedic Surgery
Vice Chief Pediatric Orthopaedics, Stanford University School of Medicine (2012 - Present)
Director of Pediatric Orthopaedic Outreach Development, Lucile Packard Children's Hospital at Stanford (2012 - Present)
Medical Education:University of Michigan GME Training Verifications (1983) MI
Residency:Yale New Haven Hospital (1988) CT
Board Certification: Orthopaedic Surgery, American Board of Orthopaedic Surgery (1991)
Fellowship:UC Davis Medical Center (1989) CA
Internship:Yale New Haven Hospital (1984) CT
M.D., University of Michigan Medical School (1983)
Current Research and Scholarly Interests
Use of umbilical cord blood in treatment of neonates "at risk" for the development of static encephalophathy
Outcomes of hip reconstruction in children with cerebral palsy
- Independent Studies (5)
Mucopolysaccharidosis IVA (Morquio A syndrome) and VI (Maroteaux-Lamy syndrome): under-recognized and challenging to diagnose
2014; 43 (3): 359-369
Mucopolysaccharidosis IVA (MPS IVA, or Morquio A syndrome) and VI (MPS VI, or Maroteaux-Lamy syndrome) are autosomal recessive lysosomal storage disorders. Skeletal abnormalities are common initial presenting symptoms and, when recognized early, may facilitate timely diagnosis and intervention, leading to improved patient outcomes. Patients with slowly progressing disease and nonclassic phenotypes can be particularly challenging to diagnose. The objective was to describe the radiographic features of patients with a delayed diagnosis of MPS IVA or VI.This was a retrospective study. The records of 5 MPS IVA and 3 MPS VI patients with delayed diagnosis were reviewed. Radiographs were evaluated by a radiologist with special expertise in skeletal dysplasias.An important common theme in these cases was the appearance of multiple epiphyseal dysplasia (MED) with epiphyseal changes seemingly confined to the capital (proximal) femoral epiphyses. Very few patients had the skeletal features of classical dysostosis multiplex.Radiologists should appreciate the wide phenotypic variability of MPS IVA and VI. The cases presented here illustrate the importance of considering MPS in the differential diagnosis of certain skeletal dysplasias/disorders, including MED, some forms of spondylo-epiphyseal dysplasia (SED), and bilateral Perthes-like disease. It is important to combine radiographic findings with clinical information to facilitate early testing and accurate diagnosis.
View details for DOI 10.1007/s00256-013-1797-y
View details for Web of Science ID 000330622300012
View details for PubMedID 24389823
View details for PubMedCentralID PMC3901942
Rapid Remineralization of the Distal Radius After Forearm Fracture in Children
JOURNAL OF PEDIATRIC ORTHOPAEDICS
2011; 31 (2): 138-143
Bone mineral content (BMC) and density (BMD) have been shown to diminish after fracture and immobilization in adults. Distal radius fractures are common in children, and unlike adults, there is a low incidence of refracture. The primary aim of this study was to assess the change in radial BMC and BMD after upper extremity fracture and casting in healthy pediatric patients.Patients were recruited at the time of distal radius fractures casting. The nonfractured (non-Fx) distal radius was initially scanned by dual energy x-ray absorptiometry (baseline), and then both arms were scanned at the time of cast removal (CastOff), and 4, 8, 12, 24, and 52 weeks post CastOff.Twenty-one patients were enrolled (13 male, 13 Caucasian; 10.4±2.5 y) with an average length of casting of 38±11 days. Eighteen patients (86%) completed all protocol requirements. At CastOff, there was no significant difference in total BMC or BMD between the Fx and non-Fx arms. From CastOff to 24 weeks, the overall change in BMC and BMD for the non-Fx arm was +4.2% and +0.2%, respectively, whereas for the Fx arm, the change was +8.3% and +3.4%, respectively. By 24 weeks, the difference in the overall change in BMD between the Fx and non-Fx arms was statistically significant (greater than instrumental error; P<0.05). However, by 52 weeks, these differences were no longer significant. The increased mineralization was unrelated to age, sex, arm dominance, or calcium intake.These data show that there is rapid remineralization after a simple forearm fracture in children, with a transient elevation in BMD in the Fx arm after casting. This novel finding suggests that bone may be stronger around the site of fracture and could significantly change how we counsel young patients recovering from forearm fracture. Future research should focus on children immobilized for varying lengths of time and those with repeat fractures, using volumetric techniques of bone geometry and strength assessment.Case series: Therapeutic Studies-investigating the results of treatment, Level IV.
View details for DOI 10.1097/BPO.0b013e3182093ddd
View details for Web of Science ID 000287190800008
View details for PubMedID 21307706
Retention of flexible intramedullary nails following treatment of pediatric femur fractures
ARCHIVES OF ORTHOPAEDIC AND TRAUMA SURGERY
2007; 127 (7): 509-514
Flexible intramedullary nails are commonly used for the treatment of diaphyseal femur fractures in children. Although, their removal after fracture healing is advocated by some, there are no definitive studies to support the routine removal of these implants. The purpose of this study is to determine the natural history of children with diaphyseal fractures of the femur treated with flexible intramedullary nails and no scheduled nail removal.We performed a retrospective case series of 24 consecutive children treated at our tertiary pediatric referral center for closed diaphyseal femur fractures. All children had intramedullary fixation with flexible titanium nails. The main outcomes measured are fracture healing, incidence of hardware removal, and pain assessment with the use of a follow-up telephone questionnaire.All the patients healed their fractures. The average follow-up time was 3.6 years. A total of six patients had removal of nails for any reason at an average of 15 months post-injury. The survivorship free of revision due to persistent pain was 72% at 5 years of follow-up. Twenty-two patients were reached by phone for a final follow-up questionnaire. There was no difference in reports of residual symptoms of pain among those who did have nails removed and those who did not (P = 0.626).Among children with femur fractures treated with flexible intramedullary nailing without scheduled implant removal, about a quarter may ultimately require a second procedure for nail removal due to persistent discomfort. Moreover, up to half of patients can have residual non-debilitating pain at 2-5 years post-injury regardless of presence or absence of the implant. Whether this is a previously unrecognized adverse outcome of this injury or treatment approach, or due to routinely leaving nails in will have to be assessed in future controlled trials.
View details for DOI 10.1007/s00402-007-0286-y
View details for Web of Science ID 000248628500003
View details for PubMedID 17237933
Scooter injuries: A new pediatric morbidity
2001; 108 (1)
To describe types of injuries, mechanisms of injury, and treatment of injuries caused by scooter use in children, and to discuss issues of injury prevention in children who use scooters.Data were collected from 14 children seen by a general pediatrician and an orthopedic surgeon over a 3-month period in the summer of 2000. Detailed histories were obtained from patients and their families, and medical records were reviewed.Eleven of the 14 patients suffered fractures. The injuries in the other 3 patients were a large abrasion, a laceration, and a septic knee. Half (7) of the children were injured within the first day of riding their scooter, and 13 of the 14 injuries occurred within the first month of scooter use. Only 5 patients used protective gear at the time of their injuries, and those patients were injured in unprotected parts of their bodies.The popularity of scooters presents a new cause of pediatric injuries and a significant health hazard to children. In our study, most injuries occurred shortly after children began scooter use, and younger children suffered the most severe injuries. Additional studies are needed to determine how scooter-related injuries can be prevented or minimized. scooters, injuries.
View details for Web of Science ID 000169571400002
View details for PubMedID 11433081
Intramedullary nailing of femoral shaft fractures in children via the trochanter tip
CLINICAL ORTHOPAEDICS AND RELATED RESEARCH
Closed rigid intramedullary nailing of femoral shaft fractures in children has been associated with avascular necrosis of the femoral head. Avascular necrosis of the femoral head is thought to result from damage to the medial femoral circumflex artery by placing the nail through the piriformis fossa. The authors describe the early results of a technique in which the nail is placed through the tip of the greater trochanter, thus avoiding the piriformis fossa and possible damage to the medial circumflex artery. Between 1988 and 1995, the authors performed this procedure on 34 patients, who ranged in age from 10 years 2 months to 17 years 6 months. Followup time ranged from 1 month to 120 months. There were no infections, nonunions, rotational deformities, or implant failures. Twenty patients with open physes had a followup of 2 years or more. To date, no patient had avascular necrosis of the femoral head develop. The trochanteric tip entry point is recommended for closed rigid intramedullary nailing of femoral shaft fractures in children and adolescents.
View details for Web of Science ID 000087915800017
View details for PubMedID 10906865
Early versus delayed reduction and pinning of type III displaced supracondylar fractures of the humerus in children: A comparative study
JOURNAL OF ORTHOPAEDIC TRAUMA
1999; 13 (1): 51-55
To determine whether children with Type III displaced supracondylar fractures of the humerus that were pinned in a delayed fashion, defined as more than eight hours after fracture, had a greater need for open reduction than patients with similar fractures pinned more urgently, within eight hours after the trauma. Also, to determine whether those patients treated later fared any worse than patients treated earlier.Retrospective review of consecutive patients.Level I pediatric trauma center at a tertiary children's hospital.Fifty-eight consecutive patients, twenty-three with early pinning and thirty-five with delayed pinning. A subgroup of sixteen patients was followed for detailed clinical outcome.Closed or open reduction and percutaneous pinningNeed for open reduction in either group. A separate subgroup was examined for carrying angle and evidence of low-grade compartment syndrome (such as grip strength and range of motion).There was no difference in the need for open reduction in the group that was delayed and pinned more than eight hours following fracture. Follow-up examination showed no clinical difference between the two groups in any parameter measured.These results indicate that many supracondylar fractures of the humerus can be treated safely in a delayed manner with an excellent clinical result and without unduly prolonging the hospital stay (such as with traction). This allows the patient to be NPO and the surgeon to operate in daylight hours, saving time, hospital resources, and fatigue.
View details for Web of Science ID 000077709700012
View details for PubMedID 9892127
Overgrowth and outcome after femoral shaft fracture in children younger than 2 years
CLINICAL ORTHOPAEDICS AND RELATED RESEARCH
Twenty-one children younger than 2 years with a fractured femur were evaluated retrospectively to determine limb overgrowth, efficacy, and outcome after treatment with immediate spica casting. All children had spica casts placed without general anesthesia within 24 hours of admission. Followup averaged 51 months (range, 24-110 months). Average shortening in the spica cast at initial application was 0.5 cm (range, 0-1.8 cm). The average length of hospitalization was 2.2 days. Three patients went home the same day, and seven were discharged after a single overnight stay in the hospital. No patients underwent closed manipulation or a cast change for malalignment of the fracture. Child abuse was identified as the mechanism of injury in eight of 12 (67%) children younger than 1 year of age and in only one of nine (11%) children between 1 and 2 years of age. Leg lengths were determined by measurement with tape and graduated blocks. At followup, the average limb length inequality was 0 cm, with an average net growth of 0.5 cm (range, -0.5-1.8 cm). Only one child had a limb length inequality of more than 1 cm as measured with tape (20 months of age), and no child had a limb length inequality of more than 1 cm as measured with blocks. No child or parent reported any residual pain, limp, or limitation of activity. The results of this study suggest that overgrowth does occur in children younger than 2 years. Additionally, immediate spica casting with early discharge to home is associated with few complications, no functional limitations, and minimal limb length inequality.
View details for Web of Science ID 000077850700025
View details for PubMedID 9917716
Skeletal traction versus external fixation for pediatric femoral shaft fractures: A comparison of hospital costs and charges
JOURNAL OF ORTHOPAEDIC TRAUMA
1998; 12 (8): 563-568
To compare the hospital costs, charges, and reimbursement for treatment of pediatric femur fractures by two treatment methods: external fixation and 90-90 traction with spica casting.Retrospective clinical review.Department of Orthopaedic Surgery, Children's Hospital Oakland, regional pediatric trauma center.Twenty-nine consecutive patients between the ages of five and ten with a fracture of the femoral shaft were treated by one of two methods: external fixation (sixteen patients) or 90-90 skeletal traction followed by spica casting (thirteen patients).External fixation or 90-90 traction followed by spica casting.Hospital billing data including costs, charges, reimbursement for the initial inpatient hospitalization, and outpatient financial data until fracture union and cessation of treatment.There was no difference in age, total treatment time, mechanism of injury, or number of associated injuries between the two groups. The average charge for treatment with skeletal traction and spica casting was $32,094 per patient versus $21,439 for external fixation (p < 0.001). The average cost for treatment with traction and spica casting was $22,396 per patient versus $11,520 for external fixation (p < 0.001); reimbursement was $30,846 and $7,490, respectively (p < 0.001). The number of days in the hospital was larger for the traction group than for the external fixation group (22.3 days versus 4.7 days, p < 0.0001).External fixation of pediatric femoral shaft fractures results in decreased hospital costs and length of hospitalization, but produces significantly less income for the hospital when compared with skeletal traction followed by spica casting.
View details for Web of Science ID 000076982000006
View details for PubMedID 9840790
Evaluation and management of pediatric foot deformities
PEDIATRIC CLINICS OF NORTH AMERICA
1996; 43 (5): 1091-?
There are myriad diagnoses that can occur in children's feet, and this article presents only a handful. Systematic evaluation beginning with a detailed history and careful physical examination, together with a knowledge of the natural history of these conditions, allows the primary care physician to be a much-needed resource for the family and provide cost-effective, efficient care while referring patients that need pediatric orthopedic intervention.
View details for Web of Science ID A1996VL38500007
View details for PubMedID 8858075
THE ROLE OF SELECTIVE DORSAL RHIZOTOMY IN CEREBRAL-PALSY - CRITICAL-EVALUATION OF A PROSPECTIVE CLINICAL-SERIES
DEVELOPMENTAL MEDICINE AND CHILD NEUROLOGY
1994; 36 (9): 755-769
This is a prospective observational study of a consecutive series of 34 children with spastic cerebral palsy treated at a single center. 10 had spastic quadriplegia and 24 had spastic diplegia. All were followed for at least one year. After selective dorsal rhizotomy (SDR), all children received one month of physical therapy at the center and were prescribed a program of physical therapy in their community. The children were assessed before and one year after SDR and physical therapy, using the Ashworth Scale, deep tendon reflex response, range of motion and the Gross Motor Function Measure. The results show that there is often a decrease in lower-extremity spasticity and functional improvement after SDR with physical therapy, but that there is considerable variability in outcome. Randomized prospective clinical trials with masked objective outcome measures are needed to determine the efficacy of SDR.
View details for Web of Science ID A1994PC85100002
View details for PubMedID 7926327
HAMSTRINGS IN CEREBRAL-PALSY CROUCH GAIT
JOURNAL OF PEDIATRIC ORTHOPAEDICS
1993; 13 (6): 722-726
After observing patients with increased anterior pelvic tilt following medial hamstring lengthening in cerebral palsy crouch gait, we became concerned that the hamstrings may be functionally important hip extensors. To evaluate this, we studied the three-dimensional motion of the hip and knee, calculated hamstring muscle length, and evaluated dynamic electromyography (EMG) of the medial hamstrings in 16 patients with diplegic cerebral palsy and crouch gait to determine if the hamstrings were extending the hip. Twelve of 16 patients exhibited marked prolongation of electrical activity in the medial hamstrings, and in eight of these 12, the hamstrings were contracting concentrically, thus aiding in hip extension during gait. Hamstrings may be important hip extensors in some cerebral palsy patients with crouch gait; however, other deformities contributing to crouch (such as hip flexion contracture) need to be considered before isolated hamstring lengthening is performed in these patients.
View details for Web of Science ID A1993MB55700006
View details for PubMedID 8245195
MAGNETIC-RESONANCE EVALUATION OF METAPHYSEAL CHANGES IN LEGG-CALVE-PERTHES DISEASE
JOURNAL OF PEDIATRIC ORTHOPAEDICS
1993; 13 (5): 602-606
Twenty involved hips in 16 patients with Legg-Calvé-Perthes disease (LCP) were studied with both plain radiographs and magnetic resonance imaging (MRI) scans to better evaluate the existence of "metaphyseal" changes. Thirty-four sets of radiographs and MRI scans were reviewed in a blinded fashion and compared for the presence and location of these changes. Of 23 hips with plain radiographic metaphyseal changes, 11 showed no such changes on MRI scans (48%). Twelve hips did show MRI changes located in the anterior metaphysis. One hip studied three times had a discrete cystic change located in the central metaphysis. Of 11 hips with no plain radiographic changes in the metaphysis, five showed metaphyseal changes on MRI. Metaphyseal changes in LCP remain poorly understood. Even with use of MRI, fine distinction between physis and metaphysis still proved difficult. It appears that most metaphyseal changes are physeal and epiphyseal irregularities. A few hips have truly metaphyseal lesions. The significance of these "cysts" is unclear.
View details for Web of Science ID A1993LT34000009
View details for PubMedID 8376560
METAPHYSEAL CYSTS IN LEGG-CALVE-PERTHES DISEASE
JOURNAL OF PEDIATRIC ORTHOPAEDICS
1991; 11 (3): 301-307
Radiographic changes in the femoral metaphysis in Legg-Calve-Perthes' (LCP) remain poorly understood. Our hypothesis was that these "cysts" are not truly metaphyseal but are metaphyseal changes radiographically projected onto the metaphysis. Surface epiphyseal changes were made on a normal hip and a hip with LCP. These "lesions" appeared metaphyseal on radiograph, and in the specimen with LCP, projected deep within the metaphysis due to flattening and three-dimensional distortion. "Metaphyseal" cysts in LCP may be epiphyseal changes superimposed on the metaphysis. This would explain the correlation between the presence of a "metaphyseal" lucency and final result, since it is simply another indicator of the extent of epiphyseal involvement.
View details for Web of Science ID A1991FG79400005
View details for PubMedID 1824031
PRIMARY CERAMIC HIP-REPLACEMENT - A PROSPECTIVE-STUDY OF 119 HIPS
1991; 14 (5): 523-531
A prospective study of 119 consecutive primary ceramic total hip arthroplasties (Autophor, Smith & Nephew) was performed. Follow up was 100% at a minimum of 3 years. Six hips were revised during the course of the study (5%). Harris hip scores were 29.0 preoperatively, 78.7 at 6 weeks, and 92.6 at 3.4 years (range: 62 to 100). Ninety-one percent of the 107 surviving hips at follow up had a good or excellent hip score. The clinical results matched those of Mittelmeier. Thigh pain was a frequent finding, but rarely presented a clinical problem. Our incidence of thigh pain may be higher than that of others because no patients were lost to follow up. The ceramic portion of the Autophor Ceramic Hip was well tolerated clinically and radiographically. The femoral component was responsible for 2% to 4% of the revisions, and we have now replaced it with a stem designed for bony stabilization.
View details for Web of Science ID A1991FL72200002
View details for PubMedID 2062729