摘要:

Metaphyseal impingement limits motion in high-grade slipped capital femoral epiphysis (SCFE). A three-dimensional volume/surface computer model was used to study the geometry of impingement, which may take the form of impaction, which causes levering or requires compensatory alteration in motion, or inclusion that occurs after remodeling and may lead to acetabular cartilage damage. The majority of deformities seen clinically can be reproduced with posterior epiphyseal displacement in the plane of the physis. By using the 3-D movements of normal walking, this model predicts little anterior metaphyseal impingement in the normal hip. As posterior slip angle increases to 25°, minor impingement can be eliminated with as little as 20° of external rotation. High-grade posterior slips (75°) require external rotation of 50-60° during walking to minimize impaction. Sitting increases impingement for all slip geometries, requiring proportionately greater external rotation. As remodeling restores a more normal arc of motion, an increasing proportion of the femoral head is composed of the remodeled, included metaphyseal prominence. This study explores the potential role of contact between the acetabulum and the metaphysis in the production of abnormal range of motion after SCFE, and simulation estimates the correction needed by osteotomy to allow normal walking and sitting. The inclusion of significant metaphyseal surfaces in the remodeled hip may be one factor in subsequent degenerative changes associated with SCFE.

ISSN:0271-6798    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

We evaluated the anatomic and functional consequences of psoas lengthening during operative intervention for developmental dislocation of the hip (DDH). Possible anatomic changes were assessed by magnetic resonance imaging (MRI), and functional assessment included strength determination by an isokinetic dynamometer and gait analysis. Six girls and one boy, ranging in age from 15 to 20 months, had operative reduction of a unilateral DDH. One closed and six open reductions (three anteromedial and three anterolateral approaches) were performed. Follow-up ranged from 4 years 0 months to 9 years 2 months. The cross-sectional area determined by MRI of the lengthened psoas muscles was markedly reduced for all of the six open-reduction patients (three moderate and three severe). Atrophy of the iliacus muscle also was apparent by MRI in five of the six open-reduction patients. Maximum flexion torque, as determined by the isokinetic dynamometer, was diminished on the DDH side for the three patients whose hips were reduced open through the anteromedial approach. Average hip-flexion torque over the entire range of motion was decreased for both anteromedial and anterolateral groups on the operated-on side. Lengthening of the psoas tendon during open reduction of a DDH is associated with considerable atrophy of the psoas muscle.

ISSN:0271-6798    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

The preosseous femoral head is thought to be vulnerable to compressive ischemic injury during the treatment of developmental dysplasia of the hip. The ossific nucleus has been proposed to increase the mechanical strength of the capital femoral epiphysis (CFE) and to decrease the risk of avascular necrosis. Sixty mixed-breed fetal and postgestational femoral head specimens were evaluated for structural stiffness in relation to the size of the ossific nucleus within the CFE. The structural stiffness of the CFE in the porcine model was found to increase exponentially with the size of the ossific nucleus. A finite-element model revealed that the presence of an ossific nucleus occupying 40% of the epiphyseal volume reduced the compressive strain in the region of the posterior-superior branch of the medial circumflex artery by an average of 54%. The results of this study support the hypothesis that the presence of the ossific nucleus may protect the CFE from compressive ischemic injury in the treatment of DDH.

ISSN:0271-6798    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Acetabular anteversion was measured by using two-dimensional (2-D) computed tomography (CT) scans in 39 dysplastic and 27 normal hips (patient age range, 3-33 years), and averaged 19.7° in the dysplastic hips and 18.1° in the normal hips. There was no statistically significant difference between the two groups, with a wide range of acetabular anteversion values noted in both groups (8-32°). Although acetabular anteversion may be increased in some patients with developmental dysplasia of the hip (DDH), it is not a universal finding. We believe that assessment and understanding of acetabular anteversion is needed before performing corrective osteotomies for hip dysplasia to optimize results and avoid the complications of acetabular retroversion.

ISSN:0271-6798    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Ninety-three standing anteroposterior (AP) pelvis roentgenograms in 87 patients were measured for a total of 186 normal hips in children aged 1-17 years. For each hip, the physeal angle relative to the floor, the physeal angle relative to the pelvis, the cartilage thickness perpendicular to the floor, and the cartilage thickness perpendicular to the physis were measured and recorded. The physeal angle varied from ages 1-7 years, stabilizing at age 8 at a mean of 23°. Physeal angle is best measured relative to the floor because pelvic obliquity introduces significant variability to the measurements. Cartilage thickness ("joint space") declined after age 7 years, with measurements in three statistically distinct groups. There was a statistically significant difference between cartilage-thickness measurements of boys versus girls, with girls showing a slightly smaller cartilage thickness than boys. Cartilage thickness measured perpendicular to the floor was not statistically significantly different from that measured perpendicular to the physis. We describe and recommend standard measurement techniques for physeal angle and cartilage thickness. These established normal values may be helpful in the diagnosis and evaluation of coxa vara and chondrolysis, and in identifying the head at risk for slipped capital femoral epiphysis or Legg-Calvé-Perthes disease.

ISSN:0271-6798    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Idiopathic chondrolysis of the hip is characterized by the destruction of the articular cartilage due to an unknown cause, principally affecting women during adolescence and producing premature degeneration of the hip. Twelve cases (11 patients) were reviewed at our hospital, with an average follow-up period of 13.2 years, during which a clinical and radiologic study was performed. Despite the treatment implemented, idiopathic chondrolysis of the hip causes progressive degeneration of the joint with the appearance of almost constant pain, stiffness, and anomalous positions. Radiologic studies show concentric narrowing of the articular space, decrease in the width of the femoral head and neck, and shortening of the affected member due to alteration in the growth physis of the upper extremity of the femur.

ISSN:0271-6798    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

A retrospective review was performed of 106 patients to determine the effect of knee pain as the initial complaint of slipped capital femoral epiphysis (SCFE). Sixteen (15%) patients had a primary complaint of distal thigh or knee pain or both at initial presentation to our institution or to a referring physician. Ninety (85%) patients described primarily hip, groin, or proximal thigh discomfort. Of the 106 patients with SCFE, 65 patients received no operative treatment before being evaluated at our institution and were the subject of the remainder of the study. Of these, 15 (23%) patients had distal thigh or knee pain or both as their chief complaint (group I), and 50 (77%) patients had hip, groin, or proximal thigh pain (group II). There was no difference between the groups with respect to age, gender, or slip stability. Group I patients were more likely to receive a misdiagnosis (p< 0.05) and undergo unnecessary or uninformative radiographs (p< 0.05). Additionally, patients in group I were found to have slips of greater radiographic severity (p< 0.05). Although not statistically significant, there was a trend for group I patients to experience a longer delay to diagnosis and to require a proximal femoral osteotomy as treatment for their slips. We conclude that isolated distal thigh or knee pain or both is a common presentation of SCFE. Furthermore, this symptom complex, when compared with the more classic presentation of SCFE, leads to higher rates of unnecessary radiographs, misdiagnoses, and severe slips, potentially increasing long-term morbidity.

ISSN:0271-6798    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Surgical management of toe-walking gait in children with cerebral palsy currently favors simultaneous, multilevel soft-tissue and bony interventions. Formulation of such a surgical plan is based on our ability to determine which of the gait deviations present are primary and which are secondary or compensatory. To evaluate this issue further, 32 normal children, walking normally and voluntarily toe-walking, were compared to 15 children with cerebral palsy walking in an obligatory toe-walking gait pattern. Computer-based analysis of gait was performed for each child, including time-distance, kinematic, kinetic, and electromyographic analyses. Significant deviations common to both normal and cerebral palsy toe-walking groups were determined to be due, at least in part, to the biomechanical constraints associated with a toe-walking gait pattern. Deviations unique to the cerebral palsy group were thought to represent primary gait deviations related to the underlying injury to the central nervous system. This study identifies the need to develop more sophisticated techniques of data collection and analysis and supports the inclusion of more varied and demanding functional activities for distinguishing between primary and secondary gait deviations in children with cerebral palsy.

ISSN:0271-6798    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Twenty-one subjects with spastic diplegic cerebral palsy were studied to quantify the effects of fixed and articulated ankle-foot orthoses (AFOs) on gait and delineate criteria for their use. Children underwent gait analysis under three conditions, fixed AFOs (FAFOs), articulated AFOs (AAFOs), and shoes alone. Greater dorsiflexion occurred at initial contact with both FAFOs and AAFOs than shoes alone. Dorsiflexion at terminal stance was greatest in AAFOs. Plantarflexor power generation at preswing was preserved in AAFOs. No differences were found in knee position during stance. Knee-extensor strength was positively related to knee extension during stance. No relationships were found between dorsiflexion range of motion, calf spasticity and strength, and peak dorsiflexion during stance. AAFOs are appropriate for subjects with varying degrees of calf spasticity, as long as adequate passive range of motion is available. These findings can be applied primarily to children who do not have a preexisting tendency to crouch.

ISSN:0271-6798    

出版商:OVID    

年代:1999

数据来源: OVID

摘要:

Kinetic data have become an important adjunct to kinematic and electromyography data in the interpretation of gait data and in the clinical decision making for children with pathologic gait patterns. A normative database is essential for comparison with the patterns of walking in children with gait abnormalities. Gait analyses of 23 able-bodied children (ages 4-10 years) were compared with those of five able-bodied adults. The patterns and amplitudes of the normal able-bodied children's kinetics showed five significant differences from those of the adults: (a) diminished hip-abduction moment, (b) diminished plantar-flexion moment, (c) diminished A2 power generation, (d) diminished knee-extensor moment, and (e) pattern of knee-power data. The data indicated a progression toward the adult normals because differences were more significant in the youngest group (4- to 5-year-olds) than in the older groups (6- to 7- and 8- to 10-year-olds).

ISSN:0271-6798    

出版商:OVID    

年代:1999

数据来源: OVID