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Biomedical subjects

J R Kasser

Publications and source records attributed to J R Kasser.

At least 19 recordsLinked to original sources
PubMed2001

Wagner multiple K-wire osteosynthesis to correct coxa vara in the young child: experience with a versatile 'tailor-made' high angle blade plate equivalent.

In 1978, Wagner described a technique using multiple Kirschner wires (K-wires) to stabilize an intertrochanteric osteotomy performed for the correction of coxa vara in small children. Multiple K-wires are used to create a custom high-angle blade plate for valgus osteotomy. The authors have evaluated a retrospective series of 17 Wagner intertrochanteric osteotomies that were performed in 10 children with coxa vara between the ages of 1 year and 8 years. The neck-shaft angle was corrected from 93.5 degrees to 129.5 degrees at long-term follow-up, and the Hilgenreiner epiphyseal angle was corrected from 71 degrees to 37.6 degrees at long-term follow-up. Revision surgery was performed on five hips with inadequate initial surgical correction. Complications included a single broken K-wire, a femur fracture after hardware removal, and one hip developed avascular necrosis postoperatively.

Bone Diseases, Developmental↗
PubMed2000

Massive subperiosteal hemorrhage and femoral shaft osteonecrosis: a complication of tissue plasminogen activator therapy for purpura fulminans.

We present the case of a child who developed a massive subperiosteal hemorrhage and subsequent osteonecrosis of her right femur after treatment with tissue plasminogen activator for post-varicella streptococcal purpura fulminans. Radiographs showed posteromedial translation of the capital femoral epiphysis on the necrotic shaft, and the hip was immobilized. The femur slowly remodeled and has continued to grow. The child is independently ambulatory with a 2.1-cm leg length discrepancy, a varus deformity of the hip, and a valgus distal femur.

Bone Remodeling↗
PubMed2000

Development of a virtual reality arthroscopic knee simulator.

The virtual reality arthroscopic knee simulator (VR-AKS) consists of a computer platform, a video display, and two force-feedback (haptic) interfaces which also monitor the position of the instruments in the user's hands. The forces that the user would normally apply to the lower limb during arthroscopy are directed through an instrumented surrogate leg. Proprietary software furnishes the mathematical representation of the physical world and replicates the visual, mechanical, and behavioral aspects of the knee while task-oriented programs monitor and record specific areas of user performance. A prototype has demonstrated the feasibility of the system and work on the first, fully functional simulator will begin soon.

Arthroscopy↗
PubMed1999

Legg-Calvé-Perthes disease: MR imaging evaluation during manual positioning of the hip--comparison with conventional arthrography.

PURPOSE: To evaluate the use of magnetic resonance (MR) imaging during manual positioning of the hip, or multipositional MR imaging, in an open-magnet configuration to study femoral head containment, articular congruency, and femoral head deformity in Legg-Calvé-Perthes disease. MATERIALS AND METHODS: In 12 children with advanced Legg-Calvé-Perthes disease, multipositional MR imaging and conventional arthrography were compared in the assessment of containment, femoroacetabular congruency, and femoral head deformity. Images of the hips in several positions were compared subjectively and objectively. RESULTS: MR imging correlated well with arthrography for overall subjective assessment of severity of disease (r = 0.71, P = .01), with good interobserver agreement (kappa = 0.65, P < .001). MR images demonstrated all cases of hinge abduction shown arthrographically. However, MR imaging failed to depict one case of femoral head flattening. MR imaging correlated well with arthrography in the objective evaluation of joint fluid and lateral subluxation (r = 0.80, P < .01). MR imaging correlated poorly with arthrography in the measurement of sphericity of the femoral head. CONCLUSION: Multipositional MR imaging with an open-magnet configuration was comparable to arthrography for demonstration of femoral head containment and congruency of the articular surfaces of the hip. In the evaluation of deformity, it performed less well.

Arthrography↗
PubMed1999

Differentiating between septic arthritis and transient synovitis of the hip in children: an evidence-based clinical prediction algorithm.

BACKGROUND: A child who has an acutely irritable hip can pose a diagnostic challenge. The purposes of this study were to determine the diagnostic value of presenting variables for differentiating between septic arthritis and transient synovitis of the hip in children and to develop an evidence-based clinical prediction algorithm for this differentiation. METHODS: We retrospectively reviewed the cases of children who were evaluated at a major tertiary-care children's hospital between 1979 and 1996 because of an acutely irritable hip. Diagnoses of true septic arthritis, presumed septic arthritis, and transient synovitis were explicitly defined on the basis of the white blood-cell count in the joint fluid, the results of cultures of joint fluid and blood, and the clinical course. Univariate analysis and multiple logistic regression analysis were used to compare groups. A probability algorithm for differentiation between septic arthritis and transient synovitis on the basis of independent multivariate predictors was constructed and tested. RESULTS: Patients who had septic arthritis differed significantly (p < 0.05) from those who had transient synovitis with regard to the erythrocyte sedimentation rate, serum white blood-cell count and differential, weight-bearing status, history of fever, temperature, evidence of effusion on radiographs, history of chills, history of recent antibiotic use, hematocrit, and gender. Patients who had true septic arthritis differed significantly (p < 0.05) from those who had presumed septic arthritis with regard to history of recent antibiotic use, history of chills, temperature, erythrocyte sedimentation rate, history of fever, gender, and serum white blood-cell differential. Four independent multivariate clinical predictors were identified to differentiate between septic arthritis and transient synovitis: history of fever, non-weight-bearing, erythrocyte sedimentation rate of at least forty millimeters per hour, and serum white blood-cell count of more than 12,000 cells per cubic millimeter (12.0 x 10(9) cells per liter). The predicted probability of septic arthritis was determined for all sixteen combinations of these four predictors and is summarized as less than 0.2 percent for zero predictors, 3.0 percent for one predictor, 40.0 percent for two predictors, 93.1 percent for three predictors, and 99.6 percent for four predictors. The chi-square test for trend and the area under the receiver operating characteristic curve indicated excellent diagnostic performance of this group of multivariate predictors in identifying septic arthritis. CONCLUSIONS: Although several variables differed significantly between the group that had septic arthritis and the group that had transient synovitis, substantial overlap in the intermediate ranges made differentiation difficult on the basis of individual variables alone. However, by combining variables, we were able to construct a set of independent multivariate predictors that, together, had excellent diagnostic performance in differentiating between septic arthritis and transient synovitis of the hip in children.

Acute Disease↗
PubMed1997

Accuracy of leg length prediction in children younger than 10 years of age.

In this study, the authors attempted to predict the ultimate leg length in normal children with normally growing legs, using Green-Anderson and Moseley techniques with chronologic and skeletal age. The predictions were based on serial growth studies of children between 5 and 10 years of age. Using skeletal age for prediction, the absolute mean error in predicting the ultimate leg length was 2.4 cm using the Green-Anderson method and 2.58 cm using the Moseley method. Using the Moseley method for length prediction in boys, the mean error was 3.8 cm using skeletal age and 1.5 cm using chronologic age. For girls, using the Moseley method of leg length prediction, the mean error was 1.55 cm with skeletal age and 2.46 cm with chronologic age. The significance of this study is that skeletal age, as determined by the Gruelich and Pyle Atlas, does not improve the accuracy of prediction of ultimate leg length in children younger than 10 years of age, except in girls with advanced bone age.

Age Determination by Skeleton↗
PubMed1997

Protrusio acetabuli and bilateral basicervical femoral neck fractures in a patient with Marfan syndrome.

A 22-year-old man with Marfan syndrome and bilateral protrusio acetabuli presented with bilateral femoral neck stress fractures after vigorous stretching exercises for hip "stiffness." Fifteen years later, his fractures, which were treated with internal fixation, have healed, his acetabular protrusion has not worsened, and his perceived hip "stiffness" persists. This case demonstrates a rare manifestation of Marfan syndrome, protrusio acetabuli, and a possible side effect of vigorous stretching in the face of abnormal joint mechanics.

Acetabulum↗
PubMed1996

MR imaging in congenital lower limb deformities.

Treatment for children with congenital deformities of the lower extremities may vary, depending on the state of the unossified skeletal structures and surrounding soft tissues. The purpose of our study was to demonstrate the spectrum of the osteochondral and extrasosseous abnormalities as depicted with MR imaging. We retrospectively reviewed MR examinations of 13 limbs of ten children (aged 1 month-9 years, mean 2.1 years) with longitudinal and transverse deformities of the lower extremities. The lesions imaged were fibular hemimelia (n = 5), tibial hemimelia (n = 5), and congenital constriction bands (n = 3). Each examination was assessed for abnormalities in the osteocartilaginous and extraosseous (articular or periarticular components such as ligaments, tendons, and menisci; the muscles and the arteries) structures. Abnormalities were seen in all patients. Osteocartilaginous abnormalities in the patients with longitudinal deformities included abnormal distal femoral epiphyses, abnormal proximal tibial physes, hypertrophied and dislocated proximal fibular epiphyses, unsuspected fibular and tibial remnants, and absence or coalition of the tarsal bones. No osteocartilaginous abnormalities were seen in the patients with congenital constriction bands. Articular abnormalities about the knee in patients with either form of hemimelia included absent cruciate ligaments and menisci, dislocated or absent cartilaginous patellae, absent patellar tendons, and abnormal collateral ligaments. All but one limb imaged had absent or attenuated muscle groups. Of the nine MR arteriograms performed at the level of the knee, eight were abnormal. The normal popliteal trifurcation was absent or in an abnormal location. We conclude that MR imaging of children with congenital lower extremity deformities shows many osteochondral and extraosseous abnormalities that are not depicted by conventional radiography. This information can help to plan early surgical intervention and prosthetic rehabilitation.

Child↗
PubMed1995

Cartilaginous abnormalities and growth disturbances in Legg-Calvé-Perthes disease: evaluation with MR imaging.

PURPOSE: To evaluate the magnetic resonance (MR) imaging appearance of cartilaginous abnormalities in Legg-Calvé-Perthes (LCP) disease and their association with growth arrest. MATERIALS AND METHODS: Twenty-seven MR images and radiographs of 25 hips in 23 patients were reviewed for epiphyseal, physeal, and metaphyseal abnormalities. Follow-up radiographs (mean time, 20.5 months) were evaluated for growth arrest. RESULTS: Epiphyseal abnormality seen in 74% of cases was not related to growth disturbances. Transphyseal bone bridging on MR images, the strongest predictor of abnormal growth (P < .01), was found in 63% of femurs. MR imaging helped detect physeal abnormalities with greater sensitivity (94%), specificity (89%), and positive predictive value (94%) than radiography. Metaphyseal extension of physeal cartilage seen in 81% of cases was associated with growth abnormality (P < .01), particularly when detected at radiography. CONCLUSION: Cartilaginous physeal and metaphyseal abnormalities in LCP disease are common and frequently result in growth arrest.

Adolescent↗
PubMed1995

Osteomyelitis and septic arthritis in children: appropriate use of imaging to guide treatment.

Modern imaging techniques have become essential components of the management of acute osteomyelitis and septic arthritis in children. This article addresses the role of these techniques, based on clinical practice guidelines recently developed at a children's hospital by an interdisciplinary group. The recommendations reflect a review of the literature and an analysis of our own experience with 84 children treated for musculoskeletal sepsis during the past 3 years. We attempt to optimize imaging resources by analyzing the unique aspects of these infections in the pediatric skeleton, the clinical needs at different stages of the disease, and the relative strengths and weaknesses of the various imaging procedures. Our goal was to define the use of imaging in cases of osteomyelitis and septic arthritis in children in specific clinical scenarios in which additional information is likely to lead to management modification.

Acute Disease↗
PubMed1994

Spinal deformity associated with neurenteric cysts in children.

STUDY DESIGN: Neurenteric cysts are uncommon lesions originating from the primitive foregut that may involve adjacent vertebrae and spinal cord. Little is known regarding the natural history of these cysts and associated spinal deformity in children. Five patients with these cysts managed at the authors' institution from 1955 to 1993 were reviewed. OBJECTIVES: The goal of this retrospective review was to determine the natural history of these cysts in children, and to assess the surgical management in each of the five patients. METHODS: Medical charts and radiographic records were reviewed and, when possible, the patients were re-evaluated clinically. RESULTS: All patients had significant anterior vertebral defects, and four had severe kyphosis at presentation. Major complications occurred in three of the four patients treated surgically. CONCLUSIONS: Iatrogenic complications of surgical management of these cysts can be limited by combined anterior and posterior approaches, providing the most complete exposure and maximal stabilization of the associated deformity.

Child↗
PubMed1994

Osteochondroma formation after a Salter II fracture.

Osteochondromas are one of the most commonly observed benign bone tumors. Although there have been a number of experimental studies carried out to determine the origin of osteochondromas, their etiology remains a controversial issue. A well-documented case is presented in which a displaced Salter-Harris type II physeal fracture preceded the development of an osteochondroma.

Child↗
PubMed1993

The function of the quadriceps muscle after a fracture of the femur in patients who are less than seventeen years old.

Thirty-three patients who had been managed for an isolated, closed fracture of the femoral shaft when they were less than seventeen years old were examined at an average of thirty-three months (range, eighteen to fifty-six months) after the injury. Thirteen patients (39 per cent) had a persistent deficit in the strength of the quadriceps of the fractured limb, as identified on testing with a Cybex-II isokinetic dynamometer. Six patients (18 per cent) had a deficit according to the one-leg-hop for distance test, fourteen (42 per cent) had an average loss of ten millimeters in the circumference of the thigh, and sixteen (48 per cent) had an average loss of 10 degrees of flexion of the knee. The etiological factors that were thought to possibly be responsible for the weakness of the quadriceps were evaluated. The amount of maximum displacement of the fracture, as seen on the initial radiographs, was the only factor that was significant for the prediction of weakness of the quadriceps (p = 0.006) at both test speeds of the Cybex dynamometer and in all statistical analyses. Despite the persistent weakness of the quadriceps, none of the patients had a clinical problem at the latest follow-up examination. A subclinical deficit in the strength of the quadriceps may be related to damage sustained by the muscle at the time of the fracture. On the basis of the results of this study, we do not recommend a change from the traditional methods of treatment, which involve early application of a spica cast or use of traction followed by application of a spica cast.

Adolescent↗