George Gorton

Outcome tools used for ambulatory children with cerebral palsy: responsiveness and minimum clinically important differences

This prospective longitudinal multicenter study of ambulatory children with cerebral palsy (CP) examined changes in outcome tool score over time, tool responsiveness, and used a systematic method for defining minimum clinically important differences (MCIDs). Three hundred and eighty‐one participants with CP (Gross Motor Function Classification System [GMFCS] Levels I–III; age range 4–18y, mean age 11y [SD 4y 4mo]; 265 diplegia, 116 hemiplegia; 230 males, 151 females). At baseline and follow‐up at least 1 year later, Functional Assessment Questionnaire, Gross Motor Function Measure, Pediatric Quality of Life Inventory, Pediatric Outcomes Data Collection Instrument, Pediatric Functional Independence Measure, temporal–spatial gait parameters, and oxygen cost were collected. Adjusted standardized response means determined tool responsiveness for nonsurgical (n=292) and surgical (n=87) groups at GMFCS Levels I to III. Most scores reaching medium or large effect sizes were for GMFCS Level III. Nonsurgical group change scores were used to calculate MCID thresholds for ambulatory children with CP. These values were verified by examining participants who changed GMFCS levels. Tools measuring function were responsive when a change large enough to cause a change in GMFCS level occurred. MCID thresholds assess change in study populations over time, and serve as the basis for designing prospective intervention studies.

Efficacy of clinical gait analysis: A systematic review

The aim of this systematic review was to evaluate and summarize the current evidence base related to the clinical efficacy of gait analysis. A literature review was conducted to identify references related to human gait analysis published between January 2000 and September 2009 plus relevant older references. The references were assessed independently by four reviewers using a hierarchical model of efficacy adapted for gait analysis, and final scores were agreed upon by at least three of the four reviewers. 1528 references were identified relating to human instrumented gait analysis. Of these, 116 original articles addressed technical accuracy efficacy, 89 addressed diagnostic accuracy efficacy, 11 addressed diagnostic thinking and treatment efficacy, seven addressed patient outcomes efficacy, and one addressed societal efficacy, with some of the articles addressing multiple levels of efficacy. This body of literature provides strong evidence for the technical, diagnostic accuracy, diagnostic thinking and treatment efficacy of gait analysis. The existing evidence also indicates efficacy at the higher levels of patient outcomes and societal cost-effectiveness, but this evidence is more sparse and does not include any randomized controlled trials. Thus, the current evidence supports the clinical efficacy of gait analysis, particularly at the lower levels of efficacy, but additional research is needed to strengthen the evidence base at the higher levels of efficacy.

Assessment of the kinematic variability among 12 motion analysis laboratories

Variability of kinematic measurements among sites participating in a collaborative research investigation is a primary factor in determining number of subjects, level of detectable difference and statistical power of a multi-site research study. In this study, one subject was evaluated by 24 examiners at 12 motion analysis laboratories and the observed variability of nine kinematic parameters are reported. Following implementation of a standardized gait analysis protocol the same subject returned for another evaluation at each of the 12 laboratories. Additionally, system accuracy and variability of the subject within and between test days are included as factors that may affect between site variability. Marker placement among examiners is identified as the largest source of variability. A 20% decrease in variability was noted following implementation of the standardized protocol.

Gross motor function classification System and outcome tools for assessing ambulatory cerebral palsy: a multicenter study

The relationships between different levels of severity of ambulatory cerebral palsy, defined by the Gross Motor Function Classification System (GMFCS), and several pediatric outcome instruments were examined. Data from the Gross Motor Function Measure (GMFM), Pediatric Orthopaedic Data Collection Instrument (PODCI), temporal-spatial gait parameters, and oxygen cost were collected from six sites. The sample size for each assessment tool ranged from 226 to 1047 participants. There were significant differences among GMFCS levels I, II, and III for many of the outcome tools assessed in this study. Strong correlations were seen between GMFCS level and each of the GMFM sections D and E scores, the PODCI measures of Transfer and Mobility, and Sports and Physical Function, Gait Velocity, and Oxygen Cost. Correlations among tools demonstrated that the GMFM sections D and E scores correlated with the largest number of other tools. Logistic regression showed GMFM section E score to be a significant predictor of GMFCS level. GMFM section E score can be used to predict GMFCS level relatively accurately (76.6%). Study data indicate that the assessed outcome tools can distinguish between children with different GMFCS levels. This study establishes justification for using the GMFCS as a classification system in clinical studies.

Outcome assessments in children with cerebral palsy, Part I: descriptive characteristics of GMFCS Levels I to III

This prospective cross‐sectional multicenter study assessed the relationships between Gross Motor Function Classification System (GMFCS) level and scores on outcome tools used in pediatric orthopedics. Five hundred and sixty‐two participants with cerebral palsy (CP; 339 males, 223 females; age range 4‐18y, mean age 11y 1mo [SD 3y 7mo]; 400 with diplegia, 162 with hemiplegia; GMFCS Levels I‐III;) completed the study. The Functional Assessment Questionnaire (FAQ), Gross Motor Function Measure (GMFM) Dimensions D and E, Pediatric Quality of Life Inventory (PedsQL), the Pediatric Outcomes Data Collection Instrument (PODCI), Pediatric Functional Independence Measure (WeeFIM), temporal‐spatial gait parameters, and O2 cost were collected during one session. Descriptive characteristics are reported by GMFCS level clinicians can use for comparison with individual children. Tools with a direct relationship between outcome scores and GMFCS levels were the PODCI Parent and Child Global Function, Transfers & Basic Mobility, and Sports and Physical Function; PODCI Parent Upper Extremity Function; WeeFIM Self‐care and Mobility; FAQ Question 1; GMFM Dimensions D and E; GMFM‐66; O2 cost; and temporal‐spatial gait parameters. Child report scores differed significantly higher than Parent scores for six of eight PODCI subscales and three of four PedsQL dimensions. Children classified into different GMFCS levels function differently.

Relationships among functional outcome measures used for assessing children with ambulatory CP

In ambulatory children with cerebral palsy (CP), practitioners often examine outcomes using measures related to functions necessary for daily life. The Gross Motor Function Measure (GMFM) Dimensions D and E, Pediatric Outcomes Data Collection Instrument (PODCI) Parent and Child versions, Gillette Functional Assessment Questionnaire (FAQ) Walking subscale, Functional Independence Measure for Children (WeeFIM), Pediatric Quality of Life Inventory (PedsQL), temporal‐spatial gait parameters, and O2 cost during ambulation were selected for study. Cross‐sectional data were collected in a prospective multicenter study of 562 participants with CP (339 males, 223 females), between 4 and 18 years of age (mean age 11y 1mo). There were 240 classified as Gross Motor Function Classification System Level I, 196 as Level II, and 126 as Level III. The tools that had the best interrelationships and underlying constructs predominately measured changes in physical function. These included portions of the FAQ, Parent PODCI, WeeFIM, and GMFM. GMFM Dimensions D and E exhibited a very strong relationship. Temporal‐spatial gait parameters and O2 cost measures represented a different construct of physical function. The Child PODCI reports and both the Parent and Child PedsQL reports did not relate well to other measures, suggesting a pattern of answers not related to question content. The Parent PODCI, the FAQ Walking subscale, and GMFM Dimension E were found to be an appropriate minimum set of instruments for assessment of functional outcomes in patients with ambulatory CP.

Comparing functional profiles of children with hemiplegic and diplegic cerebral palsy in GMFCS Levels I and II: are separate classifications needed?

The goal was to compare children with hemiplegia with those with diplegia within Gross Motor Functional Classification System (GMFCS) levels using multiple validated outcome tools. Specifically, we proposed that children with hemiplegia would have better gait and gross motor function within levels while upper extremity function would be poorer. Data were collected on 422 ambulatory children with cerebral palsy: 261 with diplegia and 161 with hemiplegia, across seven centers. Those with hemiplegia in each level performed significantly and consistently better on gait or lower extremity function and poorer on upper extremity and school function than those with diplegia. In GMFCS Level II, the group with hemiplegia walked faster (p = 0.017), scored 6.6 points higher on Dimension E of the Gross Motor Function Measure (p = 0.017), 6.7 points lower on Upper Extremity subscale of the Pediatric Outcomes Data Collection Instrument, and 9.1 points lower on WeeFIM self-care (p = 0.002). Basing motor prognosis on GMFCS level alone may underestimate lower extremity skills of children with hemiplegia, and overestimate those of children with diplegia.

Outcome assessments in children with cerebral palsy, Part II: discriminatory ability of outcome tools

Discriminatory ability of several pediatric outcome tools was assessed relative to Gross Motor Function Classification System (GMFCS) level in patients with cerebral palsy. Five hundred and sixty‐two patients (400 with diplegia, 162 with hemiplegia; 339 males, 223 females; age range 4‐18y, mean 11y 1mo [SD 3y 7mo]), classified as GMFCS Levels I to III, participated in this prospective multicenter, cross‐sectional study. All tools were completed by parents and participants when appropriate. Effect size indices (ESIs) for parametric variables and odds ratios for non‐parametric data quantified the magnitude of differences across GMFCS levels. Binary logistic regression models determined discrimination, and receiver operating characteristic curves addressed sensitivity and specificity. Between Levels I and II, the most discriminatory tools were Gross Motor Function Measure (GMFM‐66), velocity, and WeeFIM Mobility. Between Levels II and III, the most discriminatory tools were GMFM Dimension E, Pediatric Functional Independence Measure (WeeFIM) Self‐Care and Mobility, cadence, and Gillette Functional Assessment Questionnaire Question 1. Large ESIs were noted for Parent and Child reports of Pediatric Outcomes Data Collection Instrument (PODCI) Sports & Physical Function, Parent report of PODCI Global Function, GMFM Dimension E, and GMFM‐66 across all GMFCS level comparisons. The least discriminatory tools were the Quality of Life and cognition measures; however, these are important in comprehensive assessments of treatment effects.

A prospective cohort study of the effects of lower extremity orthopaedic surgery on outcome measures in ambulatory children with cerebral palsy.

Background Lower-extremity musculotendinous surgery is standard treatment for ambulatory children with deformities such as joint contractures and bony torsions resulting from cerebral palsy (CP). However, evidence of efficacy is limited to retrospective, uncontrolled studies with small sample sizes focusing on gait variables and clinical examination measures. The aim of this study was to prospectively examine whether lower-extremity musculotendinous surgery in ambulatory children with CP improves impairments and function measured by gait and clinical outcome tools beyond changes found in a concurrent matched control group. Methods Seventy-five children with spastic CP (Gross Motor Function Classification System levels I to III, age 4 to 18 y) that underwent surgery to improve gait were individually matched on the basis of sex, Gross Motor Function Classification System level, and CP subtype to a nonsurgical cohort, minimizing differences in age and Gross Motor Function Measure Dimension E. At baseline and at least 12 months after baseline or surgery, participants completed gait analysis and Gross Motor Function Measure, and parents completed outcome questionnaires. Mean changes at follow-up were compared using analysis of covariance adjusted for baseline differences. Results Surgery ranged from single-level soft tissue release to multilevel bony and/or soft tissue procedures. At follow-up, after correcting for baseline differences, Gillette Gait Index, Pediatric Outcomes Data Collection Instrument Expectations, and Pediatric Quality of Life Inventory (PedsQL) Physical Functioning improved significantly for the surgical group compared with the nonsurgical group, which showed minimal change. Conclusions On the basis of a matched concurrent data set, there was significant improvement in function after 1 year for a surgical group compared with a nonsurgical group as measured by the Gillette Gait Index, with few significant changes noted in outcome measures. Changes over 1 year are minimal in the nonsurgical group, supporting the possibility of ethically performing a randomized controlled trial using nonsurgical controls. Level of Evidence Therapeutic level 2. Prospective comparative study.

Quantifying Changes in Standing Body Segment Alignment Following Spinal Instrumentation and Fusion in Idiopathic Scoliosis Using an Optoelectronic Measurement System

STUDY DESIGN Longitudinal case studies before and after posterior spinal instrumentation and fusion (PSIF) in idiopathic scoliosis (IS). OBJECTIVES To quantitate the changes in body segment alignment following PSIF using standard radiographic techniques and an optoelectronic measurement system. SUMMARY OF BACKGROUND DATA Evaluation of surgical correction following PSIF is traditionally performed radiographically. Radiographic film cannot reliably document transverse and coronal plane pelvic, torso, and shoulder orientation resulting from the global effect of vertebral malalignment. METHODS Thirty-three subjects with IS were evaluated radiographically and with an optoelectronic measurement system before and 13 months after PSIF. All subjects had a primary right thoracic curve pattern. Thirteen subjects without scoliosis were evaluated as controls. Symmetry measures and transverse and frontal plane orientation relationships were measured and compared preop, postop, and with controls. RESULTS The major curve decreased from 60 degrees to 24 degrees after surgery. The magnitude of C7 decompensation from the sacrum decreased following PSIF. Control subjects demonstrated neutral coronal and transverse plane alignment. Preoperatively, patients had an elevated and protracted right shoulder. Postoperative data showed correction in both the coronal and transverse planes. Ten out of 33 subjects were within 5 degrees of neutral shoulder protraction before surgery. Twenty-six out of 33 were within 5 degrees of neutral following surgery. CONCLUSIONS Optoelectronic measurement of body segment alignment may be a useful noninvasive technique in the evaluation of scoliotic deformity. This is a new method of evaluating the global effect of vertebral malalignment on body segment alignment and can be used to quantify changes following PSIF.