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Dive into the research topics where Joseph Krzak is active.

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Featured researches published by Joseph Krzak.


Journal of Pediatric Orthopaedics | 2010

Long-Term Outcome Evaluation in Young Adults Following Clubfoot Surgical Release

Adam Graf; Sahar Hassani; Joseph Krzak; Jason T. Long; Angela Caudill; Ann Flanagan; Daniel Eastwood; Ken N. Kuo; Gerald F. Harris; Peter A. Smith

Background The aim of this study was to evaluate the long-term outcome of a comprehensive surgical release for congenital talipes equinovarus (CTEV). Methods Gait, strength, segmental foot motion, and outcomes questionnaire data were collected on 24 adults (21.8±2.3 y) who were surgically treated for CTEV as infants. These data were statistically compared with of 48-age group matched controls (23.2±2.4 y). Results The clubfoot group was functional in activities of daily living, although most patients did experience foot pain after a day of typical activities, such as walking, standing, using stairs and doing exercise. Lower extremity gait kinematics was similar to the control group. There were differences in segmental foot motion with the hindfoot in a more plantarflexed position relative to the tibia and the forefoot dorsiflexed, and adducted relative to the hindfoot. Ankle plantarflexion and inversion strength and range of motion was reduced in the clubfoot group in association with an increase in hip power generation during the preswing and initial swing phases of the gait cycle. Conclusions Surgical correction of CTEV was successful in providing a functional plantigrade foot as the patients reached adulthood. However, limitations included foot pain, limited foot range of motion, and weakness. Level of Evidence Level III.


Pediatric Physical Therapy | 2009

Evaluation of Short-Term Intensive Orthotic Garment Use in Children Who Have Cerebral Palsy

Ann Flanagan; Joseph Krzak; Mary Peer; Patricia Johnson; Michelle Urban

Purpose: To evaluate the effectiveness of an orthotic undergarment on gait, balance, and life skills of children who have diplegic cerebral palsy (CP). Methods: Five subjects (ages 7–13 years) with CP at Gross Motor Function Classification Scale level I wore a TheraTog™ undergarment for 12 weeks. Data collection included Vicon® Motion Analysis, Bruininks-Oseretsky Test of Motor Proficiency, and Canadian Occupational Performance Measure at baseline; in and out of the garment after 12 weeks of wear; 2 months and 4 months after garment wear. Results: Kinematic data indicated increased peak hip extension and correction of anterior pelvic tilt in stance during wear time. Composite gross motor scores on the Bruininks-Oseretsky Test of Motor Proficiency and Canadian Occupational Performance Measure scores improved significantly at the end of wear time. Conclusion: When worn for a 12-week time frame, an individualized orthotic garment can improve gait and functional skills in some children with CP.


Journal of Bone and Joint Surgery, American Volume | 2014

Behavior of scoliosis during growth in children with osteogenesis imperfecta.

Alireza K. Anissipour; Kim W. Hammerberg; Angela Caudill; Theodore Kostiuk; Sergey Tarima; Heather S. Zhao; Joseph Krzak; Peter A. Smith

BACKGROUND Spinal deformities are common in patients with osteogenesis imperfecta, a heritable disorder that causes bone fragility. The purpose of this study was to describe the behavior of spinal curvature during growth in patients with osteogenesis imperfecta and establish its relationship to disease severity and medical treatment with bisphosphonates. METHODS The medical records and radiographs of 316 patients with osteogenesis imperfecta were retrospectively reviewed. The severity of osteogenesis imperfecta was classified with the modified Sillence classification. Serial curve measurements were recorded throughout the follow-up period for each patient with scoliosis. Regression analysis was used to determine the effect of disease severity (Sillence type), patient age, and bisphosphonate treatment on the progression of scoliosis as measured with the Cobb method. RESULTS Of the 316 patients with osteogenesis imperfecta, 157 had associated scoliosis, a prevalence of 50%. Scoliosis prevalence (68%) and mean progression rate (6° per year) were the highest in the group of patients with the most severe osteogenesis imperfecta (modified Sillence type III). A group with intermediate osteogenesis imperfecta severity, modified Sillence type IV, demonstrated intermediate scoliosis values (54%, 4° per year). The patient group with the mildest form of osteogenesis imperfecta, modified Sillence type I, had the lowest scoliosis prevalence (39%) and rate of progression (1° per year). Early treatment-before the patient reached the age of six years-of type-III osteogenesis imperfecta with bisphosphonate therapy decreased the curve progression rate by 3.8° per year, which was a significant decrease. Bisphosphonate treatment had no demonstrated beneficial effect on curve behavior in patients with other types of osteogenesis imperfecta or in patients of older age. CONCLUSIONS The prevalence of scoliosis in association with osteogenesis imperfecta is high. Progression rates of scoliosis in children with osteogenesis imperfecta are variable, depending on the Sillence type of osteogenesis imperfecta. High rates of scoliosis progression in type-III and type-IV osteogenesis imperfecta contrast with a benign course in type I. Bisphosphonate therapy initiated before the patient reaches the age of six years can modulate curve progression in type-III osteogenesis imperfecta.


Journal of Orthopaedic Research | 2009

Gait characteristics and functional assessment of children with Type I Osteogenesis Imperfecta

Adam Graf; Sahar Hassani; Joseph Krzak; Angela Caudill; Ann Flanagan; Ruta Bajorunaite; Gerald F. Harris; Peter A. Smith

The purpose of this study was to improve the evaluation process of children with type I Osteogenesis Imperfecta (OI) by providing a quantitative comparison of gait and selected functional assessments to age‐matched controls. A 14‐camera Vicon Motion Analysis System was used for gait analysis along with selected functional assessments (Pediatric Outcomes Data Collection Instrument [PODCI], Functional Assessment Questionnaire [FAQ], Faces Pain Scale‐Revised [FPS‐R]) conducted on 10 subjects with type I OI and 22 age‐matched healthy controls. The results of the OI group demonstrated abnormal gait parameters including increased double support, delayed foot off, reduced ankle range of motion and plantarflexion during third rocker, along with greater ankle power absorption during terminal stance and reduced ankle power generation during push off. The functional assessment scores of the OI group were similar to the control group for basic mobility and function, but were lower than their peers in the sports and physical function category. The evaluation of individuals with OI by means of gait analysis and selected functional assessments, along with an accurate biomechanical model of the lower extremities, is proposed to better understand and predict OI disability and improve quality of life.


Developmental Medicine & Child Neurology | 2014

One-Minute Walk and modified Timed Up and Go tests in children with cerebral palsy: performance and minimum clinically important differences.

Sahar Hassani; Joseph Krzak; Barbara Johnson; Ann Flanagan; George Gorton; Anita Bagley; Sylvia Õunpuu; Mark Romness; Chester Tylkowski; Donna Oeffinger

This prospective multicenter study assessed performance and changes over time, with and without surgical intervention, in the modified Timed Up and Go (mTUG) and One‐Minute Walk tests (1MWT) in children with bilateral cerebral palsy (CP). Minimum clinically important differences (MCIDs) were established for these tools.


Gait & Posture | 2015

Kinematic Foot Types in Youth with Equinovarus Secondary to Hemiplegia

Joseph Krzak; Daniel M. Corcos; Diane L. Damiano; Adam Graf; Donald Hedeker; Peter A. Smith; Gerald F. Harris

BACKGROUND Elevated kinematic variability of the foot and ankle segments exists during gait among individuals with equinovarus secondary to hemiplegic cerebral palsy (CP). Clinicians have previously addressed such variability by developing classification schemes to identify subgroups of individuals based on their kinematics. OBJECTIVE To identify kinematic subgroups among youth with equinovarus secondary to CP using 3-dimensional multi-segment foot and ankle kinematics during locomotion as inputs for principal component analysis (PCA), and K-means cluster analysis. METHODS In a single assessment session, multi-segment foot and ankle kinematics using the Milwaukee Foot Model (MFM) were collected in 24 children/adolescents with equinovarus and 20 typically developing children/adolescents. RESULTS PCA was used as a data reduction technique on 40 variables. K-means cluster analysis was performed on the first six principal components (PCs) which accounted for 92% of the variance of the dataset. The PCs described the location and plane of involvement in the foot and ankle. Five distinct kinematic subgroups were identified using K-means clustering. Participants with equinovarus presented with variable involvement ranging from primary hindfoot or forefoot deviations to deformtiy that included both segments in multiple planes. CONCLUSION This study provides further evidence of the variability in foot characteristics associated with equinovarus secondary to hemiplegic CP. These findings would not have been detected using a single segment foot model. The identification of multiple kinematic subgroups with unique foot and ankle characteristics has the potential to improve treatment since similar patients within a subgroup are likely to benefit from the same intervention(s).


Journal of Pediatric Orthopaedics B | 2012

Comprehensive review of the functional outcome evaluation of clubfoot treatment: a preferred methodology.

Adam Graf; Kuan-Wen Wu; Peter A. Smith; Ken N. Kuo; Joseph Krzak; Gerald F. Harris

Treatment outcome has been a focus of interest in those who manage clubfeet. Because of a lack of a common evaluation protocol, it has become necessary to establish a universally recognized quantitative measurement to compare and better understand the treatment outcome. The outcome is not merely morphological and radiographic, but it should also include functional and quality-of-life measurements. In this article, we will outline the most commonly used methods of long-term evaluation for congenital clubfeet and recommend the data collection parameters that are most appropriate for a comprehensive functional analysis. This will begin with pretreatment classifications that are important in prognosticating the results. The physical examinations and plain radiographs in standing position are also two fundamental evaluations of clubfoot. Several outcome evaluations have been published in the literature and may be useful depending on the desired metrics. Gait analysis is an additional useful technical tool for analyzing the motion of the foot and ankle and its relation to the whole body function; pedobarography added to the dynamics of the evaluation. Functional quality-of-life questionnaires are increasing in popularity for measuring the total body functional status and the quality of life.


Spine deformity | 2014

Effect of Lowest Instrumented Vertebra on Trunk Mobility in Patients With Adolescent Idiopathic Scoliosis Undergoing a Posterior Spinal Fusion

Ubong I. Udoekwere; Joseph Krzak; Adam Graf; Sahar Hassani; Sergey Tarima; Mary Riordan; Peter F. Sturm; Kim W. Hammerberg; Purnendu Gupta; Alireza K. Anissipour; Gerald F. Harris

STUDY DESIGN Prospective. OBJECTIVES The goal of this study was to evaluate the effect of posterior spinal fusion surgery terminating at different lowest instrumented vertebrae (LIV) on trunk mobility in individuals with adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA Posterior spinal fusion with instrumentation is the standard surgical technique employed in AIS for correcting spine deformities with Cobb angles exceeding 50°. Surgical correction of curve deformity reduces trunk mobility and range of motion. However, conflicting findings from previous studies investigating the impact of different LIV levels on the reduction in trunk mobility after surgery have been reported. METHODS The study was designed as a prospective study with 47 patients (7 males and 40 females) with AIS who underwent posterior spinal fusion. Patients were classified into 5 groups based on their surgical LIV level (ie, T12, L1, L2, L3, and L4). Trunk flexion-extension (sagittal plane), lateral bending (coronal plane), and axial rotation (transverse plane) kinematics were assessed during preoperative, 1 year postoperative, and 2 years postoperative evaluation visits. RESULTS There were postoperative reductions of 41%, 51%, and 59% in trunk range of motion in the sagittal, coronal, and transverse planes, respectively (p < .0001). A trend toward greater postoperative reductions in peak forward flexion at more distal LIVs was observed (p = .04). CONCLUSIONS Fusion reduces trunk mobility in the sagittal, coronal, and transverse planes. More distal LIV fusions limit peak forward flexion to a greater extent which is considered clinically significant. After fusion, the reductions seen in axial rotation, lateral bending, and backward extension do not differ significantly at more distal LIVs.


international conference of the ieee engineering in medicine and biology society | 2008

Application of a bi-planar postural stability model in children with cerebral palsy

K.D. Bustamante Valles; Jason T. Long; Susan A. Riedel; Adam Graf; Joseph Krzak; Sahar Hassani; Peter A. Smith; Gerald F. Harris

This study presents initial results from a bi-planar model used to investigate the neurological factors affecting balance deficits in children with diplegic cerebral palsy (CP). The model uses an inverted pendulum to describe sway in both the anteroposterior (AP) and mediolateral (ML) planes. The study presents Center of Pressure (COP) data from 17 children diagnosed with spastic diplegic CP using two standard AMTI force plates. Sway metrics in the time and frequency domains in the AP and ML planes were calculated and compared to simulations produced by the model. The proposed bi-planar model successfully reproduced sway signals acquired from experimental (clinical) data.


international conference of the ieee engineering in medicine and biology society | 2011

Upper extremity wheelchair kinematics in children with Spinal Cord Injury

Brooke A. Slavens; Adam Graf; Joseph Krzak; Lawrence C. Vogel; Gerald F. Harris

Current methods for the evaluation of upper extremity dynamics during wheelchair mobility in children are limited. The goal of this study was to characterize upper extremity joint kinematics during wheelchair mobility. A 3-D biomechanical model of the upper extremities is presented for kinematic assessment of manual wheelchair propulsion in children with Spinal Cord Injury (SCI). The bilateral upper extremity model consists of the thorax, upper arms, forearms, and hands. The model was applied to thirteen (13) children with SCI. Joint angles and joint ranges of motion of the shoulders, elbows, and wrists were quantified. Peak joint motions during the stroke cycle were compared between right and left sides for further insight to mobility patterns. This work will provide insight to be used in future kinetic studies of wheelchair mobility.

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Adam Graf

Shriners Hospitals for Children

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Peter A. Smith

Shriners Hospitals for Children

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Sahar Hassani

Shriners Hospitals for Children

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Ann Flanagan

Shriners Hospitals for Children

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Angela Caudill

Shriners Hospitals for Children

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Haluk Altiok

Shriners Hospitals for Children

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Ken N. Kuo

Taipei Medical University

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Lawrence C. Vogel

Shriners Hospitals for Children

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Brooke A. Slavens

University of Wisconsin–Milwaukee

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