Is a Three-component Video-based Version of the Foot Posture Index Valid for Assessing Pediatric Patients With Orthopaedic and Neurologic Foot Conditions?

BACKGROUND: The Foot Posture Index-6 (FPI6) is an assessment of foot position that can be useful for patients with orthopaedic complaints. The FPI6 rates six components of foot position from -2 to +2, resulting in a total score on a continuum between -12 (severe cavus or supination) to +12 (severe planus or pronation). The subscores are ratings made by the examiner and are subjective assessments of deformity severity. The FPI6 requires palpation of bony structures around the foot and therefore must be administered live during physical examination. Because it is sometimes impractical to perform these assessments live, such as for retrospective research, a valid and reliable video-based tool would be very useful. QUESTIONS/PURPOSES: This study examines a version of the FPI using three of the original six components to determine: (1) Are scores from the three-component version of the FPI (FPI3) associated with those from the original six-component version (FPI6)? (2) Is the three-component FPI3 as reliable as the original six-component FPI6? (3) Are FPI3 assessments done retrospectively from video as reliable as those done live? METHODS: A retrospective group of 155 participants (106 males; mean age 13 ± 4 years) was studied. All had undergone gait analysis including videotaping and in-person assessment using the FPI6. Ratings for three components (calcaneus inversion/eversion, medial arch congruence, and forefoot abduction/adduction) were extracted yielding an FPI3 score ranging from -6 to +6. The other three components of the FPI6 (talar head palpation, curves above and below the lateral malleolus, talonavicular joint bulge) were excluded from the FPI3. FPI6 and FPI3 scores and side-to-side asymmetry were compared for all participants and for diagnosis subgroups (cerebral palsy and Charcot-Marie-Tooth disease) using a Pearson correlation. Agreement for foot posture categorization between the FPI6 and FPI3 was assessed using weighted kappa. Intra- and interrater reliability of live and video-based assessments for the FPI3 and its components were examined using intraclass correlation coefficients (ICCs) and Bland-Altman analysis. RESULTS: Scores from the FPI3 and FPI6 are highly associated with each other, suggesting the FPI3 is an adequate substitute for the FPI6. FPI6 and FPI3 scores (r = 0.98) and asymmetry (r = 0.96) were highly correlated overall and within the cerebral palsy (r = 0.98 for scores; r = 0.98 for asymmetry) and Charcot-Marie-Tooth (r = 0.96 for scores; r = 0.90 for asymmetry) subgroups (all p < 0.001). Agreement between the FPI6 and FPI3 was high for foot posture categorization (weighted agreement = 95%, weighted κ = 0.88; p < 0.001). Interrater reliability for live ratings was similar for FPI3 and FPI6 and high for both measures (ICC = 0.95 for FPI6 and 0.94 for FPI3; both p < 0.001). High reliability was seen in video versus live ratings for the FPI3 total score and each of its components regardless of whether they were performed by the same (ICC = 0.98) or different (ICC = 0.97) raters (both p < 0.001), and interrater reliability remained high when the FPI3 was scored from video recordings (ICC = 0.96; p < 0.001). CONCLUSION: The FPI3 is valid and reliable when done live or from video or by the same or different examiners. It is suitable for retrospective and multicenter research studies, provided videos are done using standardized protocols. Further research is recommended investigating possible ceiling and floor effects in patients with pathologic conditions.Level of Evidence Level III, diagnostic study.

Pediatric Outcomes Data Collection Instrument Scores Within Gross Motor Function Classification Scale Levels and Functional Mobility Scale Ratings in Individuals With Cerebral Palsy.

BACKGROUND AND OBJECTIVE: The Pediatric Outcomes Data Collection Instrument (PODCI) is a patient/parent-reported outcome measure used in children with cerebral palsy (CP). PODCI score variability has not been widely examined in patients of Gross Motor Function Classification System (GMFCS) level IV or using the Functional Mobility Scale (FMS). The purpose of this study is to examine the distribution of PODCI scores within patients with CP GMFCS levels I-IV and FMS levels 1-6. METHODS: Retrospectively identified patients with CP whose parent/caregiver had completed the PODCI at their visit were grouped based on GMFCS and FMS level. One-way ANOVA with pairwise Bonferroni-adjusted post hoc tests was performed to compare the effect of GMFCS and FMS levels (1, 2-4, 5, or 6) on PODCI scores. RESULTS: Three hundred sixty-seven patients were included (128 female, 11.7 years, SD 3.6). Global, Sports, Transfer, and Upper Extremity scores differed among all GMFCS levels ( P ≤0.056) and were significantly lower for GMFCS IV compared with all other levels. Happiness, Expectations, and Pain scores did not differ significantly among GMFCS levels including level IV ( P >0.06). Similar trends were seen at all FMS distances (5, 50, and 500âm). At 50âm, Global, Sports, Transfer, and Upper Extremity scores differed significantly among all FMS levels ( P <0.001) except that Upper Extremity Scores were similar between levels 2-4 and level 5 ( P =1.00). Happiness and Pain scores were not different between FMS levels ( P >0.27). Expectations scores differed only between FMS 1 and FMS 6 with FMS 6 being higher at the 50-m distance only ( P =0.03). CONCLUSIONS: Parent-reported outcome measures are important for providing patient-centered care. Providers can examine these measures alongside functional classification systems to create a more complete clinical picture of the patient. Providers should be aware of the score trends seen in our results when evaluating the PODCI for individuals with CP to improve shared decision-making and better monitor their need for future care. LEVEL OF EVIDENCE: Level III-retrospective study.

Update on the reliability of gait analysis interpretation in cerebral palsy: Inter-institution agreement.

BACKGROUND: Studies have shown good reliability for gait analysis interpretation among surgeons from the same institution. However, reliability among surgeons from different institutions remains to be determined. RESEARCH QUESTION: Is gait analysis interpretation by surgeons from different institutions as reliable as it is for surgeons from the same institution? METHODS: Gait analysis data for 67 patients with cerebral palsy (CP) were reviewed prospectively by two orthopedic surgeons from different institutions in the same state, each with > 10 years' experience interpreting gait analysis data. The surgeons identified gait problems and made treatment recommendations for each patient using a rating form. Percent agreement between raters was calculated for each problem and treatment, and compared to expected agreement based on chance using Cohen's kappa. RESULTS: For problem identification, the greatest agreement was seen for equinus (85% agreement), calcaneus (88%), in-toeing (89%), and out-toeing (90%). Agreement for the remaining problems ranged between 66-78%. Percent agreement was significantly higher than expected due to chance for all issues (p ≤ 0.01) with modest kappa values ranging from 0.12 to 0.51. Agreement between surgeons for treatment recommendations was highest for triceps surae lengthening (89% agreement), tibial derotation osteotomy (90%), and foot osteotomy (87%). Agreement for the remaining treatments ranged between 72-78%. Percent agreement for all treatments was significantly higher than the expected values (p ≤ 0.002) with modest kappa values ranging from 0.22 to 0.52. SIGNIFICANCE: Previous research established that computerized gait analysis data interpretation is reliable for surgeons within a single institution. The current study demonstrates that gait analysis interpretation can also be reliable among surgeons from different institutions. Future research should examine reliability among physicians from more institutions to confirm these results.

Anterior Distal Femoral Hemiepiphysiodesis Does Not Change Pelvic Tilt in Children With Cerebral Palsy.

BACKGROUND: Anterior distal femoral hemiepiphysiodesis (ADFH) is a surgical treatment choice to correct flexed knee gait and fixed knee flexion deformities in children with cerebral palsy who are skeletally immature. Increased anterior pelvic tilt has been reported after surgeries that correct knee flexion deformities, including hamstring lengthening (HSL) and distal femoral extension osteotomies, but anterior pelvic tilt has not been studied after ADFH. We hypothesized that anterior pelvic tilt would increase after ADFH, especially when combined with HSL, and it would correlate with the change in minimum knee flexion in stance and dynamic hamstring lengths. METHODS: Thirty-four eligible participants (age: 13.0, SD: 2.0) were included. Change in mean pelvic tilt across the gait cycle was compared as a function of clinical and gait parameters using linear mixed models. The relationship of change in pelvic tilt to change in other variables was examined using Pearson correlation. RESULTS: Overall, anterior pelvic tilt increased significantly after ADFH by 4.4 degrees ( P = 0.02). Further, the analysis revealed anterior pelvic tilt only increased significantly in the group that had concurrent HSL (11.1 degrees, P < 0.001). Overall, minimum knee flexion significantly decreased (increase in knee extension) in stance (-19.1 degrees, P < 0.001) and there was an increase in maximum normalized dynamic hamstring lengths (0.03, P < 0.001). The anterior pelvic tilt increased significantly in Gross Motor Function Classification System levels III to IV (5.9 degrees, P = 0.02) but did not change significantly in Gross Motor Function Classification System I to II (2.5 degrees, P = 0.37). Change in pelvic tilt was correlated with change in maximum dynamic hamstring lengths ( r = 0.87, P < 0.0001) and change in minimum knee flexion in stance ( r = -0.71, P < 0.0001). CONCLUSIONS: Anterior distal hemiepiphysiodesis without concurrent HSL for flexion knee deformities does not result in increased anterior pelvic tilt. Surgeons should consider anterior distal hemiepiphysiodesis in patients with cerebral palsy and flexed knee gait, who preoperatively have long dynamically modeled hamstrings, are skeletally immature, and when maintenance of pelvic tilt is desired. LEVEL OF EVIDENCE: Level III-retrospective comparative study.

Persistent increase in anterior pelvic tilt after hamstring lengthening in children with cerebral palsy.

BACKGROUND: Hamstring lengthening has traditionally been the surgical treatment of choice to correct flexed knee gait in children with cerebral palsy (CP). Improved passive knee extension and knee extension during gait are reported post hamstring lengthening, but concurrent increased anterior pelvic tilt also occurs. RESEARCH QUESTION: Does anterior pelvic tilt increase after hamstring lengthening in children with CP both in the short-term and mid-term, and what predicts increased post-operative anterior pelvic tilt? METHODS: 44 participants were included (age 7.2, SD 2.0 years; 5 GMFCS I, 17 GMFCS II, 21 GMFCS III, 1 GMFCS IV). Mean pelvic tilt was compared between visits, and the effect of potential predictors of change in pelvic tilt was examined using linear mixed models. The relationship of change in pelvic tilt to change in other variables was examined using Pearson correlation. RESULTS: Anterior pelvic tilt increased significantly post-operatively by 4.8° (p < 0.001). It remained significantly higher by 3.8° at 2-15 years follow-up (p < 0.001). Change in pelvic tilt was not affected by sex, age at surgery, GMFCS level, assistance during walking, time since surgery, or baseline values of hip extensor strength, knee extensor strength, knee flexor strength, popliteal angle, hip flexion contracture, step length, walking speed, maximum hip power in stance, or minimum knee flexion in stance. Pre-operative dynamic hamstring length was associated with greater anterior pelvic tilt at all visits but did not affect amount of change in pelvic tilt. Patients in GMFCS I-II showed a similar pattern of change in pelvic tilt to GMFCS III-IV. SIGNFICANCE: When considering hamstring lengthening for ambulatory children with CP, surgeons should weigh increased mid-term anterior pelvic tilt post-operatively with the desired outcome of improved knee extension in stance. Patients with neutral or posterior pelvic tilt and short dynamic hamstring lengths pre-operatively have lowest risk of excessive post-operative anterior pelvic tilt.

Variation in Functional Mobility Within Gross Motor Function Classification System Levels.

BACKGROUND AND OBJECTIVE: Variation in walking performance within Gross Motor Function Classification System (GMFCS) levels for patients with cerebral palsy (CP) is often unrecognized. The Functional Mobility Scale (FMS) rates mobility at household, school, and community distances. This study evaluated the variability of walking performance within GMFCS levels as measured by the FMS. METHODS: Retrospective review of gait analysis records for ambulatory patients with CP. FMS rating distribution at each distance was examined for GMFCS levels I-IV within age groups (below 12 or above 12 y) and compared among levels using χ2 tests. RESULTS: A total of 788 patients (499 male; age 11.2, SD 3.9 y) were included. FMS score distribution differed significantly among GMFCS levels for all distances (P<0.001). GMFCS LEVEL: I-Children walked independently on all surfaces at home and school distances at all ages. In all, 5% to 7% used wheeled mobility in the community. II-Most walked at home and school distances. Some younger children crawled at home, and 5% to 8% of all subjects used walls and furniture. Approximately 50% of subjects in both age groups used some form of walking aids or a stroller/wheelchair in the community. III-Twenty-five percent to 30% walked unaided at home, requiring walking aids or wheeled mobility at school or in the community. Forty-five percent of younger and 18% of older subjects crawled at home. Eight percent of younger and 28% of older subjects used wheelchairs at school. Seventy-three percent to 75% of all subjects used strollers/wheelchairs in the community. IV-Sixty-two percent of younger and 43% of older subjects crawled at home. Approximately 15% of all subjects did some aided walking at home. Twenty-seven percent of younger children did some aided walking at school, while only 1 older subject did so. All used strollers/wheelchairs in the community. CONCLUSION: Mobility function varies within each GMFCS level with the most variability in GMFCS II at school and community distances and GMFCS III at household distances. These findings highlight the importance of using both the GMFCS and FMS when assessing functional mobility in children with CP. LEVEL OF EVIDENCE: Level III-retrospective study.